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Chemical engineering education

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Title:
Chemical engineering education
Alternate Title:
CEE
Abbreviated Title:
Chem. eng. educ.
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American Society for Engineering Education -- Chemical Engineering Division
Place of Publication:
Storrs, Conn
Publisher:
Chemical Engineering Division, American Society for Engineering Education
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Frequency:
Quarterly[1962-]
Annual[ FORMER 1960-1961]
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English
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v. : ill. ; 22-28 cm.

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Chemical engineering -- Study and teaching -- Periodicals ( lcsh )

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Chemical abstracts
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Also issued online.
Dates or Sequential Designation:
1960-June 1964 ; v. 1, no. 1 (Oct. 1965)-
Numbering Peculiarities:
Publication suspended briefly: issue designated v. 1, no. 4 (June 1966) published Nov. 1967.
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Title from cover.
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Place of publication varies: Rochester, N.Y., 1965-1967; Gainesville, Fla., 1968-

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University of Florida
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70013732 ( LCCN )
0009-2479 ( ISSN )
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660/.2/071 ( ddc )

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Chemical Engineering Documents

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CEI
VOLUM 40NMER2SRIG20










INVITED GUEST EDITORIAL


For the sake of argument-


If the conventional lecture is dead,

why is it alive and thriving?


Don Woods, CEE Publications Board


Straight lecturing is the least effective way to im-
prove student learning. Students tend to remember 10
to 50% from "passive" involvement in the learning
process (we remember about 10% of what we read;
20% of what we hear; 30% of what we see; and 50%
of what we hear and see). Students remember 70 and
90%, however, if they are "actively" involved (we re-
member about 70% of what we say and 90% of what
we say and do). Also, students in learning environ-
ments where lecturing dominates become more "rote
learners"; students learning in problem-based or co-
operative learning environments become more
"deep learners."
Recently, research was done on the effectiveness of
updating courses for medical doctors. Those courses
that were lectures produced no change in practice.
Courses that included active learning components did
produce a change in practice.
Since we usually want to help students remember
and since we want graduates who are deep learners
instead of rote learners, why do faculty still give 50-
minute lectures of teacher talk? Why do universities
build more lecture auditoriums-instead of flat-floor
learning environments with movable chairs and tables
that are more conducive to cooperative and active
learning? Why do courses in teacher training focus on
"how to lecture," and "how to lecture to large classes,"
instead of "how to use active learning, cooperative
learning, or problem-based learning?" Why are fac-
ulty called "lecturers"?
Perhaps the answer is that lecturing is relatively easy,
most of us "learned" from lectures (so what's wrong
with the lecture?), and each of us gets a sense of power
and usefulness when we walk into a "lecture hall" and
all eyes look at us and wait to write down our every


thoughts. Perhaps that's the only way that we see that
we can cover the material-but our role is to uncover
material so that students learn. Perhaps we don't want
to stop lecturing even though we know there are other
options available.
So if I currently use straight lectures, what might I
do? One simple way to change from straight lecturing
to more effective learning environments is to never
have more than 20 minutes of teacher talk. Boredom
sets in after 20 minutes. A suggestion is to use a timer
set for 20 minutes to remind you to shift from "teacher
talk" to some activity.
Examples of "active" activities include:
Ask individuals to write reflections (2 min.)
then discuss with a neighbor (90 sec.)
Have students turn to their neighbor and say:
"Did you understand that?"
"Do you believe that?"
"The key point so far is ..
"A practical application of this
stuff is ...."
Ask students to compare or rework notes
Use Talk Aloud Pairs Problem Solve, or
TAPPS

Other options include using "rounds" (where stu-
dents sit in circles of about four or five and each com-
ments for about 30 seconds on a topic you pose) or
using cooperative learning groups.
The straight lecture with 50 minutes of teacher talk
really doesn't improve student learning. It's time to
change. 1













EDITORIAL AND BUSINESS ADDRESS:
Chemical Engineering Education
Department of Chemical Engineering
University of Florida Gainesville, FL 32611
PHONE and FAX : 352-392-0861
e-mail: cee@che.ufl.edu

EDITOR
Tim Anderson

ASSOCIATE EDITOR
Phillip C. Wankat

MANAGING EDITOR
Lynn Heasley

PROBLEM EDITOR
James 0. Wilkes, U. Michigan

LEARNING IN INDUSTRY EDITOR
William J. Koros, Georgia Institute of Technology

-PUBLICATIONS BOARD
CHAIRMAN *
E. Dendy Sloan, Jr.
Colorado School of Mines
VICE CHAIRMAN
John P. O'Connell
University of Virginia

MEMBERS
KristiAnseth
University of Colorado
Pablo Debenedetti
Princeton University
Dianne Dorland
Rowan University
Thomas F. Edgar
University of Texas at Austin
Richard M. Felder
North Carolina State University
Bruce A. Finlayson
University of Washington
H. Scott Fogler
University of Michigan
Carol K. Hall
North Carolina State Universit'
William J. Koros
Georgia Institute of Technology
Steve LeBlanc
University of Toledo
Ronald W. Rousseau
Georgia Institute of Technology
Stanley I. Sandler
University of Delaware
C. Stewart Slater
Rowan University
Donald R. Woods
McMaster University


Chemical Engineering Education


Volume 40


Number 2


Spring 2006


> DEPARTMENT
80 Tulane: Katrina and its Aftermath,
Brian S. Mitchell, John A. Prindle, Henry S. Ashbaugh, Vijay T. John


> EDUCATOR
74 Eric M. Stuve of the University of Washington, Bruce A. Finlayson


> CURRICULUM
88 Design Projects of the Future,
Joseph A. Shaeiwit:, Richard Turton

132 Energy Consumption vs. Energy Requirement,
L.T. Fan, Tengyan Zhang, John R. Schlup


> CLASS AND HOME PROBLEMS
140 Gas Permeation Computations with Mathematica,
Housam Binous


> RANDOM THOUGHTS
96 A Whole New Mind for A Flat World, Richard M. Felder


> THE NEXT MILLENNIUM IN CHEMICAL ENGINEERING
99 Introduction,
Christine M. Hrenya, H. Scott Fogler

104 A Vision of the Curriculum of the Future,
Robert C. Armstrong

110 Teaching Engineering in the 21st Century with a 12th-Century
Teaching Model: How Bright Is That?
Richard M. Felder

114 A Different Chemical Industry,
E.L. Cussler

116 Crystal Engineering: From Molecules To Products,
Michael F. Doherty

126 Inside the Cell: A New Paradigm for Unit Operations and Unit
Processes?
Jerome S. Schultz


CHEMICAL ENGINEERING EDUCATION (ISSN 0009-2479) is published quarterly by the Chemical Engineering
Division, American Society for Engineering Education, and is edited at the University of Florida. Correspondence
regarding editorial matter, circulation, and changes of address should be sent to CEE, Chemical Engineering Department,
University of Florida, Gainesville, FL 32611-6005. Copyright 2006 by the Chemical Engineering Division, American
Society for Engineering Education. The statements and opinions expressed in this periodical are those of the writers and not
necessarily those of the ChE Division, ASEE, which body assumes no responsibility for them. Defective copies replaced if
notified within 120 days of publication. Write for information on subscription costs andfor back copy costs and availability.
POSTMASTER: Send address changes to Chemical Engineering Education, Chemical Engineering Department, University
of Florida, Gainesville, FL 32611-6005. Periodicals Postage Paid at Gainesville, Florida, and additional post offices.


Spring 2006










educator


Eric M. Stuve


of the University of Washington



BRUCE A. FINLAYSON i
University of Washington -
Seattle, WA 98195-1750 as .


watches the Indianapolis 500 race. That's
a legacy from growing up in Indiana.
He was born in Montana, but soon afterward
his parents moved the family to the Midwest, liv-
ing in Michigan, Wisconsin, and Indiana. It's
typical of Eric that he retained his affection for
that down-home pastime even as he embraced the
intellectual challenges of studying the sciences and
pursuing a professorial career. Eric has always been
one to run his own race.


Since he was living in Milwaukee as a high-
school senior, attending the University of Wis-
consin, Milwaukee, was a natural choice. After
one year, and upon the advice of Charles G. Hill,
he transferred to the Madison campus, where he
excelled. In preparing for graduate school, Eric
was fortunate to receive good advice from the
Wisconsin professors. Ed Lightfoot reviewed fac-
ulty at a number of schools and Hill, for whom
Eric was doing an undergraduate research project,
cautioned about getting involved in surface science as it was
a lot of ultrahigh vacuum physics. It was good advice, but
Eric had other plans.
Eric's research began at Stanford, where he worked with
Bob Madix on surface reactions in ultrahigh vacuum on plati-
num and silver. He found the physics was fun. Following his
Ph.D. (1984) he went to Berlin with an Alexander von
Humboldt Fellowship in the Fritz-Haber-Institut der Max-
Planck-Gesellschaft, and it was in Berlin that he met Monika,
who was born and raised in East Germany. They wed in 1985,
which was also the year Eric came to the University of Wash-


ington, where he is now chair of the Department of Chemical
Engineering.
Eric is committed to involving students in innovative
projects in both design and research, and he brings consider-
able enthusiasm, humor, and a fundamental understanding to
all his interactions with the students.

TEACHING AND RESEARCH
With Eric, teaching and research are inseparable. Learning
by teaching has served him well. He reports that, in his first
year teaching the process design course, he learned to put


Copyright ChE Division of ASEE 2006
Chemical Engineering Education



































into perspective what he did at the molecular level, helping
him as an educator and researcher. Likewise, teaching his
first course in graduate thermodynamics challenged him to
make the homework problems relevant-and he suddenly saw
how he could bring electrical engineering and chemical en-
gineering to the course. Furthermore, he says, he had one of
those eureka moments: "I could do this."
Thus spawned his work on high electric fields, which ran
for 10 years and provided important data no one else had: A
field ion microscope was used to study field-induced surface
chemistry at very high electric fields (100 MV/cm); adsorp-
tion and reaction of water on sharp (10-100 nm) field emitter
tips elucidated the basic ionization of water to hydronium
ions and hydroxide ions induced by the electric field and the
structure of water at the interface. This information is useful
for rational catalyst design for fuel cells, understanding ice
chemistry in oceanic and atmospheric environments (ozone
hole chemistry), and development of ultra-capacitors for high-
energy/high-power electrical devices.
As he began his research at the University of Washington,
Eric branched out into electrochemical problems as well, pro-
viding the underlying support for his later work on fuel cells.
While in Berlin, he had learned how to apply electrochemi-
cal concepts to surface reactions on metal electrodes immersed
in liquids. He then built equipment that enabled comparison
of electrochemical and gas-solid surface phenomena under
nearly identical conditions. This helped elucidate the impor-
tance of potential in reactions at the fluid-solid interface. The
electrode surfaces could be analyzed using thermal desorp-
tion, low-energy electron diffraction, Auger and X-ray photo-
electron spectroscopy, and secondary ion mass spectrometry.
For his work, Eric was chosen as an NSF Presidential Young
Spring 2006


Eric and three very happy grads
let loose with some leis follow-
ing commencement ceremonies
on campus.







Investigator. Since his work was mostly
done under high vacuum, he joined the
American Vacuum Society (AVS) and, over
time, became a director, trustee, and chair
of the Investment Advisory Committee. In
his work with investments, he taught the
other scientists the concept of net present
value, which-fittingly for Eric-he had
learned by teaching the undergraduate de-
sign course. He is currently a fellow of the AVS.

FUEL CELL LOCOMOTIVE
One day Eric and a professor from Aeronautics and Astro-
nautics (Reiner Decher) came to see me in the chair's office.
They proposed making a fuel-cell driven locomotive, amuse-
ment park size.
Eric's interest was in the fuel cell, and Reiner's passion
was with trains. They explained that combining the efficiency
of a train for transporting goods with the efficiency of a fuel
cell would make an ideal system. As we talked, the image of
having a small train circle Frosh Pond during Engineering
Open House came to mind as a great crowd pleaser. Ex-
cept the thought of inexperienced undergraduates han-
dling hydrogen in a venue with thousands of middle school
kids was a scary one, to say the least.
But Eric was undeterred, and had other ideas as well. Thus
through his determination and vision was born one of the
country's best centers for fuel cell education, now encom-
passing several professors and several courses-undergradu-
ate and graduate, one of which is delivered as televised dis-
tance learning.
The goal of the Fuel Cell Locomotive Project (which be-
gan in 1996) was to produce a fuel cell system, fully con-
tained, that could provide 10 kW of power at 100 V to a pro-
ton exchange membrane system. The fuel cell would be the
prime mover for an 18-inch-gauge locomotive (one-third size)
that would pull two passenger coaches.
Eric's plan to demonstrate the train setup at an Engineer-
ing Open House got the green light, and it became a com-
bined project involving students and faculty from many dis-
75








































ciplines and two universities: the fuel cell chemistry inter-
ested chemical engineers; the special materials interested ma-
terials science students; the manufacturability interested me-
chanical engineers; and the applications interface interested
electrical engineers. Through an NSF program, students at
Penn State were also involved (in the 1997-98 school year).
The students worked in groups, which required the develop-
ment of communication skills and experience with teamwork.
It marked probably the first time these students had been ex-
posed to peer evaluation. It was also the first time most chemi-
cal engineering students came in close contact with students
in other disciplines, at least at a high, working level. A key
driving force that made the project fun was that it required
the "hands-on" design of a complex system.
The chemical engineering and materials science students
learned how to make and optimize a single cell, and then the
chemical engineering students joined the mechanical engi-
neering students to make a "stack," or several single cells
connected in electrical series. This task required designing
the flow field plates and seals, and dealing with the ever-
present safety concerns. Along the way students built sev-
eral versions of fuel cell test stands, ranging from small
to large scale.
Eric's role as project leader was to integrate all these disci-
plines and coordinate with faculty in other departments. It
involved a degree of risk since the outcome wasn't certain at
the beginning, but Eric kept a global view and ensured that
students learned something at each stage. While the mechani-
76


cal engineers were way ahead in building the rolling stock
for the train, the chemical engineers were learning that it is
hard to build a fuel cell. The fuel cells worked, but they didn't
provide enough power. Eric had the foresight to have stu-
dents each quarter build on what was learned the previous
quarter and improve it. In that way, progress was consistent
and the students had a feeling of success in achieving their
team goals.
As to my imagined fears at the outset, it turns out there was
only one explosion (no injuries). And for good measure, the
students were led through subsequent safety procedures to
see that there was never another.
On top of his success in bringing the idea to fruition, Eric
also learned how to guide such a project and avoid the end-
of-quarter rush, which is very important to those schools still
on a 10-week quarter system. In evaluating the experience,
Eric says, "Students are over-confident and under-experi-
enced." He notes the biggest problems were communication
(as in the real world) and time management (as in the real
world), but he was surprised at what they could do. The course
is definitely good preparation for work after school!
By 1999, under Eric's steady steering, the little train project
had gone from "I think I can, I think I can," to "I know I can,
I know I can."

FUEL CELL COURSES
The classroom program began to blossom when Eric asked
to teach his new fuel cell course on TV. I had been encourag-
ing faculty to present more of their specialty courses on TV
so that they could be taken by engineers who couldn't come
to campus. When Eric committed to giving it a try, we had to
rearrange the teaching schedule, with some faculty doubling
up to cover his previously assigned load, but we managed
and the course was a great success. Engineers in fuel cell
Chemical Engineering Education















As evidence of Eric's inner
drive, he insists on maintaining
his regimen of bicycling to work
even in one of the rainiest
months in Seattle's history. It
takes more than a few rain-
drops and puddles to steer
these wheels off course.


companies on both coasts took the course on TV, and ap-
proximately 160 University of Washington students and 85
distance-learning students have taken the course since 1998. It
also has been offered as a professional short course at three
national meetings of the Electrochemical Society.
With all this experience to bank on, Eric was able to part-
ner with colleague Dan Schwartz and get funding from the
Dreyfus Foundation to integrate fuel cells into the chemical
engineering curriculum. They put a fuel cell in the unit op-
erations laboratory and created new courses. Eric had already
partnered with Chevron, Apple Computer, and Boeing to pro-
vide a high-vacuum device for the undergraduate unit opera-
tions laboratory, where the students investigated Knudsen flow
in conditions pertinent to the electronics industry. But Eric
isn't satisfied with having students make things without also
understanding them.
Two classes were developed, one a course for juniors in
science and engineering (and for fuel cell professionals) and
the second a more rigorous course for seniors. As with all his
courses, Eric makes good use of PowerPoint slides that are
colorful and appeal to students for later viewing. They also
make it possible for Eric's graduate students to teach the class
as a distance-learning course (as part of a Huckabay Teach-
ing Fellowship).
Students frequently take the courses because of their de-
sire to contribute to improving society. They often report that
after the course, they appreciate how hard it is to make a fuel
cell system work, and they also are perceptive in seeing the
potential of fuel cells and recognizing that the public doesn't
understand where the hydrogen is coming from. Since Eric


attends conferences during the quarter, he comes back with
real-life examples of fuel cells that demonstrate to the stu-
dents that these are current topics and not just classroom les-
sons. As one student put it, "They are cool, very modern."
Lessons learned in the Fuel Cell Locomotive Project are
applied in the fuel cell courses, too: design projects involve
working with professors and other students, and developing
a fuel cell system that incorporates constraints of size and
functionality for real-life situations. As the courses proceed
from year to year, the projects change to reflect what was
learned previously. Since Eric is also now chair of the de-
partment, he shares the teaching load with Professors Dan
Schwartz and Stuart Adler. The fuel cell curriculum has grown
to include three faculty members and several courses. At the
undergraduate level are Introduction to Fuel Cells, Fuel Cell
Engineering, and Solid Oxide Fuel Cells. Courses at the gradu-
ate level are oriented to the scientific questions raised by fuel
cells and other reactions on surfaces: Thin Film Science, En-
gineering, and Technology; Reactions at Solid Surfaces; and
Electrons at Surfaces.
For Eric, the education program is a big part of his driving
force. He says, "If we can't work with students, I don't see
why we're here."
As a result of their experience in fuel cell projects, designs,
and courses, many of our graduates have gone to work for
fuel cell companies. Some were apprehensive about inter-
viewing with such companies, saying, "But our fuel cell didn't
work very well." In the course of their interviews, they found
out that the companies' fuel cells didn't always work well
either-and were hired!


Spring 2006










REACHING OUT TO GRADUATE STUDENTS
Befitting his individualist nature, when graduate students
start to work in Eric's lab, the first assignment he gives them is
to watch the film Dr. Strangelove. It's his habit to advise his
students on books to read, music to listen to, and movies to see.
After broadening the students' outlook on research, it's time
to get down to work. New students quickly learn Eric's man-
tra for reading a technical
paper is to read from left
to right, stop at the end of
each line, then see that you
understand it before going
on to the next one. He has
new students read three to
four papers, discuss them,
and write a research pro-
posal. This exercise sharp-
ens their critical thinking
skills and illustrates that the
generation of new knowl-
edge requires thought and
hard work.
Students then begin
working on a problem in
his lab, possibly using the A look inside
high-vacuum surface sci-
ence equipment. As the work nears the point of publication, a
draft is submitted, but it comes back covered in red ink. The
laboratory holds a copy of Fowler's Modern English Usage,
and students are expected to use it. Papers from Eric's labo-
ratory don't have author lists as long as the abstract; you are
expected to do the work yourself. As you might expect, some
of his graduate students are getting a chemistry degree, and
he teaches those students chemical engineering principles,
too; he thinks everyone should know them! Eric believes in
thorough preparation. His students are prepared for the fu-
ture by writing and rewriting papers, and by presenting the
work at conferences, always with a fundamental look at the
problem. As you'd expect, Eric's Ph.D. students work pre-
dominately in companies dealing with fuel cells, electrochem-
istry, and surface science (see Table 1).

LAUNCHING A LAB
Sometimes a researcher will look around for a problem that
can be solved with techniques and instruments he/she has
available. Not Eric. He sees a problem and thinks how best
to solve it, then proceeds. It was in this fashion that he built
up his laboratory equipment to be the extensive lab that it is
today (see Table 2). The philosophy does require creativity,
though, since it often means learning a new area that one
hasn't formally studied. Thus, the effects of high electric
fields, ceramics (and solid oxide fuel cells), and linear
density functional theory were things he learned in re-
78


e Er


sponse to particular problems.
One example of this philosophy in action is how Eric's
group was able to resolve a scientific argument. The back-
ground involves a focus of current research: namely, to de-
termine the reaction mechanisms that occur at surfaces. A
major application is direct methanol fuel cells (DMFC) for
portable power and low-power applications. Teasing out the
mechanism for the oxidation of
methanol on platinum and plati-
num plus ruthenium requires
careful work, often under high
vacuum. Yet, the understanding
is essential if DMFCs are to
become widespread. Begin-
ning with the Langmuir-
Hinshelwood surface reac-
tions, mechanisms are proposed
and then experiments designed
to determine the rate-controlling
steps. Some researchers felt the
reaction followed a parallel path,
while others insisted it was a
serial path. By elucidating four
different controlling rates of re-
action, Eric's group was able to
ic's lab. determine that the previous find-
ings in favor of the series path
were the result of reaction conditions and catalyst modifiers
(e.g., ruthenium). Both sets of reactions are necessary, but
local conditions determine which ones apply in any given
situation.
Since fuel cells operate at temperatures above room tem-
perature, Eric conducts studies at higher temperatures, too.
More recently, work on solid-oxide-supported platinum cata-
lysts supports the goal of fuel cells that run on diesel or other
hydrocarbon fuels without having to reform the fuel to pro-
duce hydrogen. Copper-ceria electrocatalysts minimize car-
bon formation, thus avoiding the problems of nickel-based
electrocatalysts. Solid oxide fuel cells have strong potential
for use in transportation, defense, and industrial and residen-
tial applications.
The fundamentals of surface science have widespread ap-
plication in other fields, too. The power of fundamentals was
brought home to me one day when I was reading a paper
about how polymers slip while being extruded, but the phe-
nomena seemed to depend upon the type of surface. I asked
Eric about that, and described some of the surfaces mentioned
briefly in the paper. He proceeded to line them up for me,
explaining which ones would allow slip at the lowest pres-
sure drop, etc. Impressed, I called the author (at an industrial
laboratory); the paper had not been completely forthcoming,
but the author confirmed that the sequence Eric provided was
exactly what was found in the laboratory.

Chemical Engineering Education











ERIC AS CHAIR
Eric was appointed acting chair of chemical engineering in
1999 and soon became the permanent chair. One of the high-
lights of his chairmanship has been the preparation and ex-
ecution of the department's Centennial, a celebration of the
beginning of the department in 1904. It involved hundreds of
people to organize, and Eric seems to have tapped into his
student experience as an actor and techie to pull off the pag-
eantry to the last detail. With Eric in the driver's seat, the
event was carefully crafted to show off the department to
alumni, the university, and ourselves. He reports he had the
usual "opening night" jitters, but all the planning made for a
memorable event. In the end, even his planning for contin-
gencies got tested, as a thunderstorm erupted just as we were
about to leave the luncheon to walk to the laboratories.
Eric enjoys hearing stories from retired alumni and values
their friendships. In turn, alumni have been very generous to
the department, and Eric loves the stories they tell about
chemical engineering in the "early days." Chuck Matthaei
(of Roman Meal Bread) has shown great interest in educa-
tion and recently endowed a professorship. Neil Duffie (of
Willamette Industries) knows what is important and chal-
lenges Eric to think strategically; Neil has been a longtime
supporter of graduate fellowships.

PERSONAL CHARACTERISTICS
I have always valued Eric's creative side. If there is an idea
to explore "outside the box," Eric is one of the people I want
in the group. In addition to his comprehensive knowledge,
his willingness to forge his own path means he has a knack
of looking at problems in different, sometimes quirky, ways,
and this spawns new ideas.
Eric is not all fuel cells and surface reactions, though. Well-
known for his love of Gary Larson's Far Side cartoons, he
has an endearing sense of humor that can defuse tense situa-
tions. His love of music is also well known: He and his wife
Monika attend the opening night of Seattle Opera every year.
Eric even drew upon his theatrical side at the departmental


TABLE 1
Stuve's Ph.D. Graduates

Naushad Kizhakevariam Varian in Portland
Rod Borup Los Alamos National Laboratories
David Sauer Intel
Thomas Jarvi UTC Fuel Cells
Timothy Pinkerton Intel
Dawn Scovell Intel
Suresh Sriramulu Tiax Consulting (formerly Arthur D. Little)
Seng-Woon (David) Lim UW Chemistry Dept.
Thomas H. Madden United Technologies Research Center
Chris Rothfuss U.S. Department of State
Nallakkan Arvindan Symyx Corp.

Spring 2006


holiday party in December 2005, when he serenaded the at-
tendees by singing "O Tannenbaum."
Further evidence of his well-developed nonscientific side
is his practiced penmanship: Eric's mother was artistic, and
Eric learned calligraphy-so well, in fact, that his wife re-
quires a card done in the elegant writing style for birthdays
and special events. The artistic streak carries over to Monika,
as well, who has achieved "teacher" status in Ikebana flower
arranging. She quickly learned the Japanese art and has even
displayed her accomplishments at a Seattle show along with
a Japanese master and his entourage.
The Stuves also enjoy traveling, and one benefit of Eric's
fuel cell research has been an increase in opportunities to do
so. A repeat destination is Bangkok, Thailand, as part of an
exchange program Eric participates in with Dow Chemical
and the Chemical Technology Department of Chulalongkom
University. During their last visit, they encountered a situa-
tion we all hope to avoid. As the plane took off from Bangkok,
a bird flew into an engine and the pilot aborted the takeoff. In
the process, a wheel caught fire, and the plane was evacuated
at the end of the runway. While the plane was quickly empty-
ing, Eric was concerned about his wife and son Kurt, who
were also onboard. As if sliding down the chute weren't
enough excitement, it took some time for the family to re-
unite. Then, more problems appeared. Since everyone had
left their carry-on baggage on the plane, no one had their
passport. Thus, they could not enter Thailand again while
waiting for another plane the next day! Eventually, sanity
occurred among the authorities, and the passengers were taken
to a nearby hotel to spend the night. The next day the plane
took off without incident, and Eric and his family returned to
Seattle safe and sound, and none the worse for wear. Leave it
to Eric to take such an unplanned "pit stop" in stride.

CONCLUSION
With his commitment to keeping students on the right track
and his fundamental approach to problems, you might say Eric
is the kind of chemical engineering educator who helps set the
pace for our profession. Not bad for an Indy fan. 1


TABLE 2
Equipment in Stuve's Laboratory
Differential Electrochemical Mass Spectrometer
Ultra-high vacuum (UHV) analysis chamber (4)
Potential step chronoamerometry
Linear and nonlinear electrochemical impedance spectroscopy (EIS and NLEIS)
Field Ionization/Emission Microscopy (FIM/FEM)
X-ray photoelectron spectroscopy (XPS or ESCA)
Low energy electron diffraction (LEED)
Thermal desorption spectroscopy (TDS)
Time-of-flight mass spectrometer (TOF-MS)
Auger electron spectroscopy (AES)
Contact potential difference (CPD)
Electron stimulated desorption ion angular distribution (ESDIAD)










] department


Some exhausted members of the Tulane University Uptown recovery team on Sept. 15, 2005-two weeks after
Hurricane Katrina. Left to right: Greg Potter (chemistry, Washington Univ.), James Peel (Bruker Instruments), Russell
Schmehl (chemistry), David Mullin (cell and molecular biology), Scott Grayson (chemistry), Qi Zhao (chemistry),
Gary McPherson (chemistry), W Godbey (CBE), Brian Mitchell (CBE), Vijay John (CBE), and Bob Garry (microbiology).



From Survival to Renewal


Katrina and its Aftermath

at Tulane's Chemical and Biomolecular Engineering Department



BRIAN S. MITCHELL, JOHN A. PRINDLE, HENRY S. ASHBAUGH, AND VIJAY T. JOHN
Tulane University New Orleans, LA 70118


he Chemical and Biomolecular Engineering Depart-
ment at Tulane University has a rich tradition dating
back to 1894, as the first established program in chemi-
cal engineering in the South and the third program in the coun-
try.'" Tulane University faced a struggle for survival in the
fall of 2005 when the city of New Orleans was devastated in
the wake of the flooding from Hurricane Katrina. This article
chronicles the experiences of the department and its efforts
not just to maintain viability but also to look to the future
with a renewed sense of purpose. In keeping with the


university's approach to describing the events of the period
between Aug. 29, 2005, and the present, the article is divided
into three sections: survival, recovery, and renewal.
As background, we give the reader an idea of the depart-
ment. At the time of Katrina, there were nine full-time fac-
ulty (Professors O'Connor, Papadopoulos, Law, Mitchell,
Ashbaugh, Godbey, Lu, De Kee, and John), two staff mem-
bers (Dr. Prindle who serves as a senior instructor and labo-
ratory supervisor, and Ms. Lacoste, the departmental admin-
istrative secretary), and Professor Emeritus Gonzalez, who


Copyright ChE Division of ASEE 2006
Chemical Engineering Education










participates in teaching graduate courses and in collabora-
tive research. The department had about 30 graduate students
studying toward their Ph.D., and about five part-time M.S.
students. Undergraduate enrollment was about 80 with gradu-
ating classes between 15 and 20 students. Undergraduate in-
terest in the program, and enrollment numbers along with it,
saw a steady increase as a result of the recent emphasis and
inclusion of biomolecular engineering into the curricu-
lum in 2003.

SURVIVAL
Residents in the New Orleans area are accustomed to threats
from hurricanes, but there had been none to hit the city since
Betsy in 1965. The horrendous traffic jams and inconve-
niences of evacuation that were experienced when Hurricanes
Georges and Ivan came close but missed the city convinced
many that evacuation was unnecessary. A
sense of complacency had set in. But
Katrina was no mere threat. By Aug. 25, it It was pc
was clear the storm was zeroing in on the heartwa
New Orleans area. Some 300 miles off
shore, the hurricane strengthened to a Cat- the g
egory 5 status, giving sufficient reason for students
the university to initiate evacuation plans helping u
for students. Ironically enough, the week- labor
end of Aug. 27 was supposed to be the resume
faculty's annual welcoming of the latest activity
batch of freshmen, but hasty departures though
were being urged instead. President Scott damage
Cowen called a meeting of all students and mnts,
ments, th
requested that they all return home or
evacuate to Jackson on buses the univer- up and
sity had arranged. Temporary housing had livable
also been arranged for evacuating students opened t
at Jackson State University. Our faculty and hem
made individual plans for the storm while wit
making sure their graduate students had
concrete evacuation plans. Two of our fac-
ulty decided not to evacuate prior to Katrina, but the conse-
quent flooding and the infrastructure and security issues in
the city mandated they leave a few days after the hurricane.
Most faculty and students first evacuated toward the Baton
Rouge, Houston, and Jackson areas.
The events of Hurricane Katrina have been well docu-
mented. We all watched the disaster in real time with acute
sadness, for we could clearly identify with all the locations
in the images. The stress was heightened by the fact that
phones were not working and we were unable to get in touch
with our colleagues and students. Tulane's information tech-
nology services were disrupted and university e-mail ad-
dresses were useless. Communication was slowly established
through text-messaging and the use of temporary e-mail ad-
dresses. It was at this time that Hank Ashbaugh got through


to colleagues in the chemical engineering community with
his request for help in placing our students (see box on page
82 for his personal recollections). Vijay John followed up
with a separate e-mail. The department will forever be grate-
ful for the outpouring of help for our students and faculty.
The major ChE departments geographically closest to
Tulane-in Houston and in Baton Rouge (Rice, the Univer-
sity of Houston, and LSU) took in many of our students and
offered our faculty laboratory and office space-we are so
tremendously thankful.
Katrina wrought significant damage to Tulane. Two-thirds
of our picturesque campus in the historic Uptown neighbor-
hood of New Orleans had flooded. Winds from Katrina dam-
aged the roofs of several buildings. The computer systems
were down, with the university backup tapes located safely
yet inaccessibly in high-rise buildings downtown near the
Superdome, the site of so much trauma and
sadness. The upper administration was op-
cularly rating from Tulane's Executive Business
S School campus in Houston-the saga of
g to see how they brought back function to opera-
late tions and coordinated the recovery is an
ck and interesting story in itself (see
ean the ). The breakdown in
ies to payroll systems was the first major crisis,
earch since the university had no idea how to is-
Even sue paychecks or even a way to identify
le had those on its payroll. We were dealing with
part- emergency financial personnel who had to
teamed be educated that a graduate stipend simply
meant salary. With the help of the deans,
-e with department chairs, and faculty members, all
Itments employees and graduate students were
r doors identified and paychecks issued through
o those direct deposit. Professor Dan De Kee, who
it. also serves as the associate dean for gradu-
ate studies, was invaluable as he kept the
pressure on payroll administration from his
evacuation location of Gaithersburg, Md. In many instances,
the university simply took the word of the deans that indi-
viduals belonged on the payroll and issued paychecks. It is to
the credit of the university that all employees and graduate
students were paid during the entirety of the period be-
tween Sept. 1 and Dec. 31, 2005, while the university re-
mained closed.
Within a couple of weeks following Katrina, faculty mem-
bers Brian Mitchell and Vijay John-who live to the north
and to the west of the city-had returned to their homes, grate-
ful to find minimal damage. John Prindle, who lives near
Baton Rouge and had not evacuated, served as a communi-
cations conduit (see his personal account in box on page 83).
Hank Ashbaugh slowly traveled from Jacksonville, Fla., up
the eastern seaboard to Troy, N.Y. (Rensselaer) where he even-


Spring 2006


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Professor Hank Ashbaugh's recollections of
connecting with his research group and
the chemical engineering community

After Hurricane Katrina hit on Aug. 29, 2005, a sense
of helplessness grew in me as I watched the perpetual
coverage of the flooding of New Orleans from my father's
house in Jacksonville, Fla. The storm had knocked out
the phone network for anyone with a New Orleans area
code, so communications with the faculty in my depart-
ment were spotty at best. Foremost on my mind was where
my research group had scattered in the wake of Katrina.
I quickly located one postdoc who still had a New York
area code on his cell phone, and learned that he'd safely
evacuated with Professor Yunfeng Lu's group to Shreve-
port, La. More worrisome were the two graduate students
from India who had just arrived in the United States to
join my group the week before the storm. How do you
locate two newcomers to this country who had scattered
in a panic? Then I remembered that I had recruited these
two students from UICT with the help of Professor VG.
Pangarkar. I e-mailed him at 11 p.m. and by 2 a.m. my
two students had contacted me to say they were safely on
their way to Texas.
My success in locating my far-flung group gave me the
idea that we should try to reconstitute the department over
the Internet. The first step was to locate the individual
faculty members. The Internet servers for Tulane had been
shut down before the storm, so using campus e-mail ad-
dresses was out. Instead, on Sept. 1, I wrote an open e-
mail to the chemical engineering community-copying
every department chair-to tell our story and request the
whereabouts of any Tulane faculty. The response was
phenomenal. Over the course of the next three days I re-
sponded to over 400 e-mails wishing us well, volunteer-
ing support, and, more importantly, giving me clues as to
where our faculty had evacuated. Within a week and a
half I managed to locate all our faculty, get alternate con-
tact information for each, and begin to reassemble the
department. Two weeks after the storm I sent a second e-
mail to the ChE community providing news ofourfaculty's
whereabouts. As faculty members were being located, we
started to compile lists of graduate and undergraduate
students to expand our "virtual" department. Using the
contacts we had developed outside the department, we
were able to connect students with departments and uni-
versities that had volunteered to host them during our
semester in exile. To facilitate interdepartmental commu-
nications, we created a blog ( TulaneCBE/>) to disseminate information on support for
students, student registration, communications from our
chair, and miscellaneous tidbits. Moreover, the blog pro-
vided a window for our friends outside the department to
keep updated on our status. I


tually spent the rest of the semester. During his travels, he
stopped in at universities along the way (North Carolina, Dela-
ware, Princeton) where he had studied. Kyriakos
Papadopoulos also evacuated to New York (Columbia) after
a two-week stay in Lafayette, La. W Godbey ended up in
Houston (Rice) by way of Huntington, W.Va., Dallas, Texas,
Grapevine, Texas, and Fort Smith, Ark. Kim O'Connor went
to Houston (Baylor Medical School); Yunfeng Lu to Albu-
querque (University of New Mexico) by way of Houston;
Richard Gonzalez to Jackson, Miss.; and Ms. Lacoste to rela-
tives who live north of the city. Victor Law went to Angleton,
Texas, and had to evacuate a second time due to Hurricane
Rita. Our students were scattered all over the country and
were welcomed in at all universities. We had survived the
hurricane. The next step was to plan our recovery.

RECOVERY
The early days following the hurricane, when the campus
and surrounding Uptown neighborhood were without elec-
trical power, are detailed in Brian Mitchell's account of the
recovery efforts (see box on page 85). The university hired
Belfor, an international disaster-recovery corporation, and the
campus was teeming with Belfor employees. Huge power
generators and trailers were scattered across campus as Belfor
set about draining water from building basements (note: base-
ments in New Orleans = bad idea!), gutting damaged floors,
and reinstalling utilities. By early to mid-October, electrical
power had been restored to the neighborhood and most of the
campus had power, with the notable exception of the science
building where electrical transformers and other utilities
placed in the basement had been destroyed. The university's
senior administration had returned to the city and had started
operations in the main administration building (Gibson Hall).
From there they monitored the recovery and began the strat-
egy for renewal.
From the department's perspective, this was a time to take
stock of our losses. Brian Mitchell, Vijay John, and John
Prindle were among a handful of faculty and staff cleared for
regular entry into the engineering building. All other employ-
ees had to get clearance to enter the building (usually by call-
ing Brian or Nick Altiero, the dean) and were escorted into
the engineering building by Brian to recover computer hard
drives, etc. There were significant safety issues, as the build-
ing ventilation systems had not yet been decontaminated.
During the months of October and November, the computer
and communication systems at Tulane returned to normal
operation and we slowly transitioned back to our university
e-mail addresses. It was an interesting time, as Brian, John,
and Vijay came in almost every day to man the phones, keep-
ing in touch with our colleagues and our students. We had to
balance these duties with our personal lives, in which Katrina
had impacted school openings for our children, job condi-
tions for our spouses, and much more. There was very little


Chemical Engineering Education










time for intellectual work. It was a time in which we all real-
ized the frailty of the human condition and learned to act
with newfound compassion. Three of our colleagues had suf-
fered such damage to their homes that they needed tempo-
rary housing. Overall at Tulane, 25-40 percent of the employ-
ees had homes significantly damaged by flooding. There was,
and continues to be, a resounding spirit of helping one another.
We learned several lessons from our experiences in sur-
vival and recovery that are useful to pass on. When planning
for disasters, science and engineering departments should al-
ways take into account the consequences of electrical power
and communication failures
for extended periods. It is wise
to maintain extra supplies of
liquid nitrogen to preserve bio-
logical samples. Personnel and
graduate students should have
alternative e-mails that can be
accessed anywhere through
the Internet. Inventories of
chemicals, instruments, and
general property must be
maintained by the department.
Access to buildings under re-
pair should be tightly con-
trolled even to employees-a
faculty member paying a nos-
talgic visit to the medical
school building before the
power had been restored is
said to have caused significant
water damage by using the
plumbing while the system
was under repair. Even if
thawed biologicals (e.g., tissue
samples) have been removed,
decontamination of the entire W Godbey contempt
building must be performed his dewarfull of


under professional supervision.
By early December, most buildings were functional and
the campus was being spruced up for the return of the stu-
dents. Faculty members throughout the university were ex-
cited about returning to work. President Cowen and the up-
per administration had done a wonderful job in maintaining
student morale by presenting Tulane as a unique institution
where rigorous education would be combined with excep-
tional opportunities to participate in public service to rebuild
a great city. Early registration rates were high and the faculty
was looking forward to the future. We knew that the univer-


lates the whoosh of liquid nitrogen vapors that indicated
biological samples was still cold-evidence that years
of research were still safe.


Dr. John Prindle's recollections of maintaining connections with the undergraduates
Students are any chemical engineering department's lifeblood. They challenge ihe faculty to continually improve teaching
skills. Their tuition pays for a portion of the department's expenses. And with each freshmen class comes a distinctive
view of the world and how to improve it. In many ways, students are a department's primary legacy. So, it is not surprising
that a strong personal connection forms between faculty members and each student they instruct.
In the aftermath of Hurricane Katrina, this personal connection was severely tested. For more than a month after the
event, the university's network servers were down, rendering the familiar student e-mail addresses useless. Shortly after
Tulane announced it was canceling the fall semester, students began calling faculty at home to discuss their options.
Student concerns ranged from whether they should attend another university for the semester to whether they should
register for chemical engineering coursework at that university. During these discussions, the faculty realized most
students simply wanted to be reassured that we would assist them any way we could. With each call, students were
See Maintaining Connections with Undergraduates,
continued on page 98

Spring 2006 8





































Members of the faculty and instructional staff in less stressful times. From left, standing: W T. Godbey,
Daniel De Kee, Vijay John, Yunfeng Lu, Kim O'Connor, Kyriakos Papadopoulos, Brian Mitchell,
and John Prindle. Seated: Richard Gonzalez, Hank Ashbaugh, Victor Law.


sity, as with all employers in the New Orleans region, would
be in a difficult financial situation. But there was a conta-
gious spirit to get the students back, work hard, build up re-
search, and try to recover. It was particularly heartwarming
to see the graduate students back and helping us clean the
laboratories to resume research activities. Even though some
had damaged apartments, they teamed up and those with liv-
able apartments opened their doors and hearts to those with-
out. Yunfeng Lu, who lives a block from campus, feverishly
worked to repair his damaged home so his sizable group of
graduate students could have a place to stay if they were un-
able to find appropriate accommodations.

RENEWAL
On Dec. 8, the Board of Administrators at Tulane Univer-
sity announced a renewal plan as a consequence of the finan-
cial exigency. The plan has turned out to be the largest re-
structuring of an American institution of higher education on
record. Under the plan, some 230 faculty members were ter-
minated, including 35 members of the School of Engineer-
ing. The Departments of Civil and Environmental Engineer-
ing, Mechanical Engineering, Electrical Engineering, and
Computer Science have been slated for elimination by the
fall of 2007. The university has been reorganized with the
formation of a School of Liberal Arts and a School of Sci-
ence and Engineering, in addition to the professional schools,
to fully constitute a comprehensive university. Chemical and


Biomolecular Engineering is one of only two surviving engi-
neering departments; Biomedical Engineering is the other.
Both were merged into the School of Science and Engineer-
ing, which has been further divided into academic divisions.
Biomedical Engineering is now part of the Division of Bio-
logical Sciences and Engineering. Chemical and Biomolecu-
lar Engineering and the Department of Chemistry form the
Division of Chemical Science and Engineering. The entire
renewal plan makes for fascinating reading for those inter-
ested in academic organization, strategy, and administration.
It can be found at . Long-term
goals of the plan as stated by the Board of Administrators
are: (1) diligence in retaining our institutional quality and
working to heighten that quality; (2) dedication to providing
an unparalleled, holistic undergraduate experience for our
students; (3) continued strengthening of core research areas
and graduate programs that build on our strengths and can
achieve world-class excellence; and (4) an absolute commit-
ment to using the lessons learned from Katrina to help re-
build the city of New Orleans and to then extend those les-
sons to other communities.
We mourn the breakup of the School of Engineering, an
institution that existed for over a century. We also mourn the
departure of our colleagues who have worked tirelessly to
improve the school. It is sufficient to say that we will con-
tinue to work hard toward enhancing the reputation of the
department. The current dean of the engineering school, Nick
Chemical Engineering Education










Altiero, has been appointed the new dean of the School of
Science and Engineering. We believe his appointment indi-
cates the university's recognition that engineering is still a
significant and continuing component of Tulane, and we look
forward to working with him to renew, reconstitute, and ex-
pand engineering as opportunities present themselves. He has
been clearly told that the Board of Administrators will be
receptive to new ideas for engineering at Tulane upon return
to financial stability.
What is the future of the department? The university is ex-
pected to return to financial stability within a couple of years,
with the bond market expressing confidence in the strong
management team at Tulane.2'1 Our student body has returned
and we are back to high intensity in both research and educa-
tion. Our informal merger with chemistry is a seamless fit.
Over the years, the two departments have formed strong
bonds, with research collaborations and an environment of
mutual support. The atmosphere of cooperation has led to
the establishment of superb instrumentation facilities in ad-
vanced spectroscopy, electron microscopy, and organic and
inorganic analysis. We are especially proud of our high-reso-
lution electron microscopy and confocal microscopy facili-
ties wherein we are instituting a full range of cryoimaging
techniques for biological imaging. Collaborations with the
Medical School have been set up and we are considered a
vital player in Tulane's objective to become world-class in
health sciences research. Such collaborations are in stem-cell
culture, gene delivery to cancer cells, and vaccine develop-
ment and delivery technologies. The department has signifi-
cant strengths in the areas of computational chemistry, self-
assembly, nanostructured materials, colloid science, and poly-
mer and ceramics processing. The university has clearly stated
its intent to bring every Ph.D.-granting department up to na-
tional prominence, and we expect significant investments to
our department as the university returns to financial viability.
The next couple of years will be difficult. In addition to
their intellectual lives, faculty and students will worry about


rebuilding their personal lives, which must come first. Kind-
ness and compassion will be the order of the day in the de-
partment in dealing with such issues. It will also be terribly
exciting to witness and participate in the rebuilding of the
city. It is incredibly heartening to see students mobilizing on
all kinds of public service projects, from involvement in public
school education, to gutting destroyed houses so that resi-
dents can return to rebuild and establish communities, to pro-
viding meals to the thousands of laborers who are working to
rebuild the city.
We are determined to persevere. Please wish us well ..
and come visit.

ACKNOWLEDGMENTS
W T. Godbey made very helpful suggestions to the article.
The faculty, staff, and students of the Department of Chemi-
cal and Biomolecular Engineering express our deepest grati-
tude to our colleagues in the chemical engineering commu-
nity for their many gestures of kindness in the wake of Hur-
ricane Katrina, and for their numerous forms of support in
helping us to re-attain our prestorm level of excellence.
Department chair's note: I am privileged to work with my
faculty and staff colleagues who showed so much courage
and dedication to restoring the department to viability. The
three coauthors of this article (Prindle, Ashbaugh, and
Mitchell) were especially helpful with their efforts to contact
every undergraduate and graduate student and their efforts to
restore the research infrastructure. They were always avail-
able to help, and Professor Mitchell coordinated the entire re-
covery aspects of the engineering school. To rebuild the depart-
ment with such colleagues is the best job I could hope for.

REFERENCES
1. Westwater, J.W., "The Beginnings of Chemical Engineering in the
USA," Adv. Chem. Setr, 190 141 (1980)
2. Chronicle of Higher Education, Jan. 27 (2006)
3. Walz, J.Y., Chem. Eng. Ed., 246, Fall (1995) 0


Professor Brian Mitchell's narrative on the recovery of our physical facilities
Two weeks after Hurricane Katrina, the department's personnel situation was still critical, but much more stable. All
faculty and staff had been located and were in communication, most undergraduates had been advised which courses to
take at their host institutions, and graduate students were in contact with their advisors. While many continued to struggle
with personal issues related to assessment of their home damage, FEMA, the Red Cross, insurance, accommodations,
and informingfriends and family of their whereabouts, it became clear that it was time to give some attention to the status
of departmental facilities, especially those related to research. The concern for research facilities was uniform through-
out Tulane's research community, but the urgency in engineering was associated primarily with biological samples that had
now been in unreplenished liquid nitrogen (LN)-cooled dewars for two weeks in the sweltering New Orleans summer heat.
Laura Levy, senior vice president for research, authorized a convoy for Sept. 15 to the Tulane campuses to assess
damage. The convoy, led by John Clements, professor and chair of microbiology and immunology, departed early that
Thursday morningfrom the Tulane University Regional Primate Center in Covington, which is located on the Northshore
See Recovery of Physical Facilities
continued on page 86

Spring 2006 8.











Recovery of Physical Facilities
Continued from page 85


of Lake Pontchartrain and had not received any significant
damage from the storm. The eight-vehicle convoy consisted
of researchers from both Uptown (Engineering and Science)
and Downtown (Medical School) campuses, and traversed
the 24-mile Lake Pontchartrain Causeway bridge in record-
setting time with the assistance of a police escort. Its entrance
into the city marked for many of the recovery-team members
their first views of Metairie and New Orleans since the hur-
ricane. The sights, sounds, and smells did not bode well for
finding facilities intact.


Upon arriving at the Uptown campus, the
Downtown team continued on to the more
heavily damaged Medical School campus,
while the representatives from Science and
Engineering set to work. The team from the
Chemical and Biomolecular Engineering
Department consisted of Professor and
Chair Vijay T. John, Assistant Professor W
T. Godbey, and Professor Brian S. Mitchell.
Flashlights in hand, the team entered the
Lindy Claiborne Boggs Center for Energy
and Biotechnology around 9 a.m., and
trudged up the back stairs to the third and
fourth floors that comprise the bulk of the
department's research facilities.
An initial scan of the department showed
it to be in relatively good condition: no


blown-out windows, no water damage, and no indications of
unauthorized entry, save for one broken interior window in
the department's Electronic Classroom. A keypad on the door
and no missing equipment in the classroom soon led to the
conclusion that security personnel had broken the glass sim-
ply to gain entry and evaluate damage. As doors were opened
and each lab inspected, hope grew that the department had
evaded major damage. Lab benches looked as if students had
simply left for lunch. Only one lab had minor damage, the
result of a window being left partially open and the hurri-
cane-force winds toppling some glassware.
The team then concentrated its efforts on two general ar-
eas: securing biological samples and recovering research
data. W Godbey was elated to find that his LN, dewar full of
biological samples-including rare cells and tissue specimens
that were collected over years of research--was still cold.
(One can equate his joy at seeing the cold, white cloud rise
from his liquid nitrogen storage freezer with the emotions
exhibited by JPL engineers when a probe successfully lands
on Mars.) He quickly replenished the dewar with LN, from a
pre-Katrina storage tank in his lab, and did the same with


Professor Kim O'Connor's samples in an adjacent labora-
tory. The team then collected biological samples from dew-
ars in the Biomedical Engineering Department, consolidated
the samples into one 25 1 dewar with wheels, and placed the
dewar by a service elevator to facilitate future refilling op-
erations. Some thought was given to carrying the portable
dear down the stairs and placing it on the first floor since
there was no power in the building, but there were indica-
tions that power to the elevators could be restored on a tem-
porary basis, if necessary. Unfortunately, biological samples
that had been frozen in a refrigerator freezer were no longer
cold and had begun to decompose. DNA samples that had
been placed in a freezer to slow decomposition could with-
stand room temperatures for moderate time periods, so they
were still salvageable and were therefore re-
trieved.


Similar operations related to the collection
and consolidation of biological samples were
conducted in the chemistry and biochemistry
departments, as well as at the Downtown cam-
pus. For example, a recent Public Broadcast-
ing NOVA segment documents the heroic efforts
of Tulane researcher Tyler Curiel to save irre-
placeable sinonasal undifferentiated carcinoma
(SNUC) samples from his laboratory ( www.pbs.org/wgbh/nova/sciencenow/3302/
08.html>). LN, is also critical to the operation
of some advanced analytical tools, such as
Nuclear Magnetic Resonance Spectrometers
(NMRs). Gary McPherson and Russell
Schmehl, our colleagues from chemistry, dili-
gently worked to ensure that the NMR magnets


in both the Department of Chemistry and Tulane's Coordi-
nated Instrumentation Facility (CIF) did not quench. Even-
tually, these units also required that their liquid helium res-
ervoirs be recharged, a task which involved several other
dedicated individuals from both chemistry and CIF.
The recovery of research data consisted primarily of re-
trieving laboratory notebooks and computers fiom investi-
gators' offices and labs. It was unknown at that point how
long the university would remain closed, and some investi-
gators had not decided whether to relocate to other universi-
ties for the semester. Many opted to leave their computers for
the time being. As it turned out, Tulane would be closed for
the entire semester, and many faculty members did indeed
relocate to continue their research, if only out of their homes.
As a result, many computers and hard drives were retrieved
during subsequent recovery trips. The retrieval and shipping
of computers for faculty, staff, and graduate students proved
to be problematic. Some requested only hard drives, which
required opening computers, and some requested not only
computers, but monitors and other peripherals as well. Ship-
ment of large pieces of equipment required travel to neigh-


Chemical Engineering Education


As doors were
opened and each
lab inspected, hope
grew that the
department had
evaded major
damage. Lab
benches looked as
if students had
simply left for
lunch.









































boring communities where postal facilities were open (and
packed with people trying to get their mail). In some cases,
computers and supplies were driven to their final destina-
tions by faculty or staff members. Much of this effort could
have been avoided with proper data storage practices. Though
there are certainly security and accessibility issues with off-
site data storage, in a case like this, in which faculty is forced
to scatter to various locations without sufficient warning to
retrieve or back up data, the ability to retrieve important in-
formation from a neutral site would be invaluable. One such
resource currently under development is the Louisiana Opti-
cal Network Initiative (LONI)- LONI2005/)>-which will provide a high-speed optical net-
work for researchers at a number of Louisiana universities,
including Tulane. But until such networks are in place and
easily accessible to the research community, individual in-
vestigators must accept the responsibility for ensuring that
their research data are secure and readily retrievable. A list
of other "Lessons Learned" is shown in Table 1. An area for
further research is listed in Table 2.
By Sept. 26, residents were being allowed back into Or-
leans Parish on a limited basis, so police escorts and con-
voys were no longer necessary. Recovery trips to the campus
continued, and it was during the ensuing six- to eight-week
period that the majority of computers and research equip-
ment were removed to allow investigators to continue their
research at external sites. In most instances, the investiga-
tors, or their representatives, were escorted onto the Uptown
campus by either the dean of engineering or his designee. All


TABLE 2
More Information Needed

There is an issue with vapor phase vs. liquid phase storage of
biologicals: There is a high probability that fungal spores will be
floating in LN,, and if the storage tubes are submerged in the liquid
then there is a chance of sample contamination. On the other hand, a
full dewar. if left unopened, can keep samples cold for months. Some
kind of study would help clarify whether liquid phase storage is
indeed safe for biologicals.

visitors to campus had to be cleared with the Office of Public
Safety prior to their visits, and random identification checks
from armed security officers were the norm. A system was
established for recording institutional identification numbers
for all equipment removed from the campus. Investigators
were allowed to remove equipment for research purposes,
but were informed that doing so could have insurance impli-
cations; i.e., if there was hurricane-related damage, they may
not be able to prove it since insurance adjustors had not yet
arrived on campus. A few investigators moved their labs-
equipment, graduate students, and all-to host universities
for the semester. Some chose to remain at Tulane and carry
out their research with graduate students who had either re-
mained behind or returned. By mid-November, escorted vis-
its had virtually ceased, cleanup operations were well under
way, and the Department of Chemical and Biomolecular
Engineering was gearing up for the spring term. Tulane
University officially opened to faculty and staff on Dec.
19, 2005, and the spring 2006 term began Jan. 16, 2006,
right on schedule. O


Spring 2006


TABLE 1
Some Lessons Learned

For brief power interruptions, a chest freezer is preferable to an upright freezer for storage of biologicals at -80 because it will remain
cold for longer periods of time.
If space and funds permit, store biological samples in LN, rather than a freezer, because
a full LN, dewar will stay cold for months, even in 100 F heat, if unopened: however...
Biological the storage of tissue samples with bacterial samples creates a potential contamination issue, so ...
a a transform bacteria and lyophilize the modified culture broths with bacteria in them, for storage at room temperature for
indefinite periods of time.
Keep an adequate supply of LN, on hand.
Consolidate LN, samples into one container whenever amenable, even if that means sharing one between laboratories, subject to the
constraints described above.

Back up your electronic data on a regular basis to an easily retrievable location.
Research Consider replacing your desktop computer with a laptop and docking station so data is easily portable in an emergency.
Data Have students store research notes, laboratory notebooks, and samples in a predefined location so critical nonelectronic data can be
easily located in their absence.
Store flammable research notebooks in a fireproof and waterproof container.

Place all electrical devices on appropriately sized battery backups with surge protection to guard against short-term power interruptions.
Electrical
Equipment For longer power interruptions, if time permits, shut down all electrical devices and turn off electrical breakers to prevent damage due
to power surges upon being re-energized.











re curriculum


DESIGN PROJECTS OF THE FUTURE






JOSEPH A. SHAEIWITZ AND RICHARD TURTON
West Virginia University Morgantown, WV 26506-6102


It is generally accepted that the chemical engineering pro-
fession is in a state of change. Fewer graduates from U.S.
chemical engineering departments are entering the pe-
troleum, petrochemical, and chemical industries, since most
expansion in these industries is not in the United States. More
graduates from U.S. chemical engineering departments are
entering product-based industries (e.g., pharmaceutical, food,
new materials) rather than the traditional commodity-chemi-
cal-based industries (ethylene oxide, benzene, sulfuric
acid)."' 2 Therefore, changes in the undergraduate chemical
engineering curriculum-which has been static for about 40
years (not counting advances in computing)-are imminent,
if not already in progress.
Three significant changes in the chemical engineering cur-
riculum are under way.13' First of all, biology is now consid-
ered to be an "enabling" science, along with chemistry and
physics. Some education in the life sciences will soon be re-
quired for accreditation.[4] Secondly, chemical engineers need
to be taught about product design, either instead of or in ad-
dition to process design. It will become more important to
teach batch operations, since the manufacture of new chemi-
cal products will certainly involve batch rather than continu-
ous operations. Finally, over the past generation, advances in
chemical engineering research have involved the ability to
understand and to manipulate phenomena at the colloidal,
nano, molecular, and atomic scales. A key issue is the effect
on macroscopic properties of colloidal-, nano-, molecular-,
and atomic-scale phenomena, i.e., structure-property relations.
It is time these advances became part of the undergraduate
curriculum.
Radical changes to the traditional chemical engineering
curriculum have been proposed.'' Changes are on the hori-
zon, although the speed and degree of implementation of these
changes is not yet obvious. It could also be argued, however,
that traditional chemical process engineering must still be
taught, because the soon-to-retire baby boom generation must
88


be replaced by newcomers equally capable of operating, main-
taining, and updating existing chemical plants.
Given the importance of the capstone experience in the
undergraduate education process, a question that arises when
considering curriculum changes is: What will the capstone
chemical engineering design project of the future look like?
It is virtually certain that the capstone chemical engineering
project of the future will not involve sulfuric acid or ethylene
oxide production. Instead, it may have a life science basis. It
may involve design of a product. It may involve multiscale
phenomena, i.e., the effect of nano- or molecular-scale inter-
actions on the performance of the product. It is more likely to
involve batch processing than continuous processing. And, it
is also possible that manufacture of items and unit packag-
ing-two concepts far removed from traditional chemical
engineering-will be included.


Joseph A. Shaeiwitz received his B.S. de-
gree from the University of Delaware and his
M.S. and Ph.D. degrees from Carnegie
Mellon University His professional interests
are in design, design education, and out-
comes assessment. Joe is an associate edi-
tor of Journal of Engineering Education, and
he is a co-author of the text Analysis, Syn-
thesis, and Design of Chemical Processes
(2nd Ed.), publishedby Prentice Hall in 2003.


Richard Turton received his B.S. degree
from the University of Nottingham and his
M.S. and Ph.D. degrees from Oregon State
University. His research interests are in flu-
idization and particle technology and their
application to particle coating for pharma-
ceutical applications. Dick is a co-author of
the text Analysis, Synthesis, and Design of
Chemical Processes (2nd Ed.), publishedby
Prentice Hall in 2003.

Copyright ChE Division of ASEE 2006
Chemical Engineering Education











In an effort to initiate a new capstone-design paradigm, the
yearlong capstone design project at West Virginia University
for 2003-04 and 2004-05 involved biologically oriented,
multiscale product designs. These two projects are described
in this paper. More details are available elsewhere'"5 and from
the authors.

CLASS ORGANIZATION
In the senior year of chemical engineering at West Virginia
University, the entire class works on a large project for two
semesters under the direction of a student chief engineer. More
details are presented elsewhere.161 Briefly, faculty members
play roles: one is the client, for whom the students are "hired"
to complete a design project; another is the "vice president"
of the students' company, who helps the students with tech-
nical matters. The student chief engineer divides the class
into groups, each headed by a group leader. The role of the
chief engineer is to represent the entire team to the client and
to provide leadership from the "big picture" perspective. The
group leaders receive assignments from the chief engineer
and are responsible for completing the work within their
groups. Assignments are deliberately vague and open ended.
One goal is to force students to define their own work state-
ment, with input from faculty members. Another is to learn
material not normally taught in class. The exact topics stu-
dents must learn are a function of the project. A further goal


is to make students realize that they will have to continue
learning new material throughout their careers, and that they
have the ability to do so.
In the fall semester, the project involves researching alter-
natives and a feasibility study. For example, in ice cream pro-
duction, the assignment was to identify, screen, and recom-
mend food products for production, with attention focused
on products that have low-fat and/or low-carbohydrate alter-
natives. Students set their own direction with a minimum of
input from the instructors. The client chooses one alternative
for design in the spring semester. This is really the only op-
portunity for the instructors to influence the direction of the
project; however, the client's choice is always one of the top
two student recommendations.


ICE CREAM PRODUCTION
This project was completed by 26 students over the course
of the entire 2004-05 academic year. It started with a very
open-ended assignment: to investigate opportunities in food
processing, particularly those involving low-fat and low-car-
bohydrate alternatives. The market for these foods was to be
analyzed, and the issues associated with producing the low-
fat and low-carbohydrate alternatives were to be identified.
A summary of the colloidal- and molecular-scale issues iden-
tified by students is shown Table 1. Production of any of these


TABLE 1
Examples of Colloidal- and Molecular-Scale Processing Challenges in Food Manufacturing

Product Processing Challenge

Ice Cream Ice crystal formation must be kept to a minimum. Otherwise, the ice cream has a grainy texture.
Nut and fruit size must be controlled to control the rheology. Processing conditions must be controlled to prevent nuts and fruit
additives from becoming soggy.

One method for making low-fat ice cream have the same mouth feel as regular ice cream is slow churning, a proprietary process of
Edy/Dreyers.'1 By churning the ice cream at higher pressures and lower temperatures, smaller, more dispersed fat globules are
formed that have similar mouth feel to regular ice cream.

Cookies Almond flour is often substituted for wheat flour in low-carbohydrate cookies. Since almond flour contains more fat, the result is a
chewier cookie.

Granulated sugar is required in cookie manufacture so that the sugar will spread throughout the cookie during baking. Coarse sugar
results in cracking. This has implications as to which sugar substitute can be used in low-carbohydrate cookies.

Reduced-fat cookies require longer baking times to allow the existing fat to coat the flour and sugar particles.

For sandwich cookies to stick together, the surface energy of the solid must be higher than that of the filling. One way to accom-
plish this is to raise the temperature of the filling and add more fat to the filling, both of which reduce its surface energy. (This is
also true for ice cream sandwiches.)

Bread Protein and fiber are often substituted for wheat flour in low-carbohydrate bread. Binding agents are required to hold these
ingredients together. Dough conditioners are added for strength.

Cereal Bars Binders are added to hold the cereal pieces together. They crosslink to form a flow-resistant structure. There are two common
binders. One involves dipolar interactions between OH groups on glucose molecules in the binder and the cereal pieces. The other
involves COO- groups bonding covalently with the cereal pieces.

Spring 2006 89










products would make a good design project. Each involves
batch processing of a product as well as manipulation at the
molecular or colloidal levels to obtain desired macroscopic
properties. Another feature involved, but traditionally unfa-
miliar to chemical engineers, is packaging.
Students used product screening methods to rank the alter-
natives.[71 Ultimately, ice cream production to capture 1% of
the domestic market was chosen for a complete design. Pro-
duction of 1.75-quart containers plus some novelties (pops
and bars, in this case) were included in the design. Ice cream
production involves traditional chemical engineering, prod-
uct design, and multiscale analysis. It involves application of
principles of chemical engineering at scales from the mo-
lecular level to the process level.
Ice Cream Science. There are three categories of ingredi-
ents in the ice cream mix: dairy, sweeteners, and additives.
Milk, cream, and nonfat milk solids make up the dairy por-
tion of ice cream. Sucrose or Splenda is used to sweeten the
mix, and stabilizers and emulsifiers are added to give the ice
cream the desired body and mouth feel. Significant quanti-
ties of air are also present in finished ice cream. Standard ice
cream contains an equal volume of mix and air, or an "over-
run" of 100%. Premium ice cream, however, has an overrun
of only 80% to give it a richer, more-creamy,
mouth feel.


Stabilizers and emulsifiers are essential in the production
of ice cream products. Both components help to give ice cream
a smooth body and texture and help to improve the overall
mouth feel of the ice cream. Stabilizers work by reducing the
amount of free water in the ice cream mixture. This retards
ice-crystal growth during storage and also provides resistance
to melting. Stabilization is accomplished through two mecha-
nisms, depending on the type of stabilizer used, and both
mechanisms may be involved depending on the structure of
the gum used. Charged gums, such as carageenan, help to
reduce the amount of free water because the charged groups
interact with water to restrict the movement of water mol-
ecules within the mixture. Branched gums, such as guar gum,
also reduce free water within the system. This is accomplished
because the branched side chains contain hydroxyl groups
that hydrogen-bond with water, a reaction that also reduces
the amount of free water. Similarly, emulsifiers help to re-
duce fat-globule coalescence by stabilizing the fat globules
within the ice cream matrix. Mono- and diglycerides are the
most commonly used emulsifying agents. The addition of sta-
bilizers and emulsifiers is particularly important for ice
cream base mixes that are lower in fat content, because
whole milk already contains natural stabilizing and emul-
sifying materials.


Milk is a colloidal suspension of water,
fat, and milk solids. Fat particles in the sus-
pension range in size from 0.8 to 20 pm. The
sugar-lactose-is also present in milk, at a
concentration of about 4.9%. In "lactose-
free" ice creams, the milk is treated with
the enzyme lactase, which breaks lactose
down into the simpler sugars glucose and
galactose.
In this design, regular table sugar, or su-
crose, is used as a sweetener in all the ice
cream mixes except the low-carbohydrate ice
cream. Sucralose is used to sweeten the low-
carbohydrate ice cream because it is indigest-
ible but still sweetens the mix.


0

0
S,
> 5 -

A I
^,


0 5 10 15 20 25
Shear Rate (1/sec)


*Atkins Low-Carb
* Kroger Standard
A Haagen-Dazs@ Premium


30 35 40


Figure 1. Viscosity of different ice cream products.


Mixing Pasteurization & AgngFlavor
-' Ingredients Homogenization Aging Mixing





-- Freezing Cartoning Hardening



Chemical Engineering Education


Figure 2.
Block flow diagram
for ice cream
production.










The viscosity of ice cream varies with the type. During a
class tour of a local ice cream production facility, the host
remarked that production of low-carbohydrate ice cream was
"difficult on the equipment," which had been placed into
operation before low-carbohydrate ice cream was developed.
Further investigation revealed that many ice creams, particu-
larly the low-carbohydrate vanillas, contain TiO, pigments
to make the ice cream look whiter. It is possible that the TiO,
colloidal particles cause erosion of process equipment. Stu-
dents also wondered whether there was a variation between
viscosities of different ice cream types. One student, who was
doing research in the polymer research laboratory of our col-
league Rakesh Gupta, measured the viscosity of three types of
ice cream. The results are shown in Figure 1. Low-carbohy-
drate ice cream is clearly more viscous than standard ice cream.
Facility Design. A facility to manufacture, store, and ship
ice cream was designed. Production volumes were 52 mil-
lion 1.75-quart ice cream containers (varying flavors), 2.3
million six-packs of sandwiches, and 4.3 million six-packs
of pops (ice cream bars with sticks). The manufacturing pro-
cess of the ice cream facility is broken down into seven steps,
as illustrated in Figure 2. A 5400-m2 warehouse for ice cream
storage was also designed. It was designed to hold three
months of production. Because of the need to refrigerate the
warehouse, the construction requires special insulation, and
the capital investment for this part of the process (>80%)
dominates the overall fixed capital investment (almost $100
million)-a result that was not anticipated.


Refrigeration Cycle. Refrigeration (600 tons) is required
three places: in the warehouse, in the hardening step in ice
cream production, and for cooling the milk at the front end of
the process. An ammonia refrigeration-cycle design, used for
the warehouse, is displayed in Figure 3. The refrigeration cycle
is a traditional chemical engineering component of this de-
sign. Using the number of interstate coolers on the compres-
sors and the type of cooling medium used in E-101 through
E-104 as decision variables, students optimized the refrig-
eration process.

Steam Generation. In the facility, low-pressure steam is
used for pasteurization, for jacketed heating of the mixing
equipment, and for heating water for equipment cleaning.
These steps are necessary to ensure that there is no product
contamination by bacteria, which is part of "good manufac-
turing processes" in food production. Therefore, a typical
steam-production facility was designed.

Wastewater. A system was designed to process wastewater
from the ice cream manufacturing facility. There were two
reasons for this. First, it was assumed that the ice cream plant
would produce too much additional wastewater for an exist-
ing municipal wastewater facility. Second, based on infor-
mation from the local water authority, having a water treat-
ment facility in-house appeared to be the less-expensive op-
tion. Wastewater treatment is needed because the equipment
must be cleaned daily, generating significant amounts of
wastewater. The operation plan involves production on two







C-103


Figure 3.
CW C-104 PFD for the
optimized
16 ammonia
refrigeration
cw E-102 system
Wf n\n, unit 1.


Spring 2006













Figure 4.
Block flow diagram
for transdermal
drug delivery patch
manufacture.


shifts per day followed by a cleaning shift. Most
of the cleaning is done using hot water.
Economics. It costs approximately $0.56 to
produce a 1.75-quart container of ice cream, in-
cluding the initial capital investment. Even with
the markup associated with the food distribu-
tion chain, the process is very profitable. The
net present value (NPV) was found to be $97
million, assuming a 10-year plant lifetime and
a 15% before-tax rate of return. A Monte Carlo
analysis showed that there is only an 8% chance
of losing money, i.e., an NPV less than zero.
Remarks from an ice cream expert at the final
student presentation indicated that prices for
milk products could vary over a wide range,
leading to significantly greater variation in the
NPV. These factors were not considered in
the students' analysis but could easily be in-
corporated.

DESIGN OF A TRANSDERMAL
DRUG DELIVERY SYSTEM


Patch Stratum
Corneum


This project was completed by 11 students
over the course of the entire 2003-04 academic
year. It also started with a very open-ended as-
signment: to investigate alternative forms of
drug delivery, and to suggest a product to be
manufactured. Within the transdermal patch
category, students learned the properties that
make a drug suitable for use in a transdermal
Pa
patch, which are: (1) low molecular weight, (2)
high potency, so low dosage required, (3) resis-
tance to enzymes in skin layers, and (4) desire
to have constant dosage in body over time. Item
number 4 means that a transdermal patch would
not be used to treat a simple headache, because,
for a headache, rapid entry of the drug into the
blood is desired. Students used product-
screening methods to choose between alternative drugs."'
Ultimately, production of a contraceptive transdermal
patch for females was chosen for a complete design.


Epidermis


K,

C1


C2



Patch Stratum
Corneum


Dermis Capillary Blood
Wall


C2.





c2,=o C3=0

Blood


Figure 5. Model for diffusion through skin layers.


Figure 6. Two-compartment pharmacokinetic model.

Patch Design. The patch contains norelgestromin and ethinyl
estradiol. The proposed size of the patch is 10 cm2, manufac-
tured as a single-layer, matrix system.


Chemical Engineering Education


Weighing
- & Coating Drying Laminatio-
Mixing



Cutting
SInspection ----- & Cartoning
1 Packaging


Co


M, M,










Pressure-sensitive adhesives are the common form of ad-
hesive used in transdermal systems. They are permanently
tacky at room temperature, they are easily applied with light
pressure, and they do not require solvents for activation.
Polyisobutylene was chosen because it provides excellent
adhesion in high-moisture environments and because of its low
cost. Polyisobutylene has a surface tension of 30-32 dyne/cm,
which is lower than the critical surface tension of skin of 38-
56 dyne/cm, depending on humidity and temperature. There-
fore, the adhesive will wet the skin-a requirement for adhe-
sion. This is an example of colloid-scale considerations in
the transdermal patch design.
Skin penetration enhancers increase the mass flux of a drug
across the desired surface area. The driving force for the drug
is the concentration gradient between the patch and the skin.
The enhancer used in this patch is crospovidone, which draws
water to the surface of the skin. This in turn causes swelling,
which provides more surface area for diffusion.
Excipients are ingredients within a drug product that are
considered inactive, from a pharmacological perspective. In
this case, there is one excipient used, propylene glycol
monolaurate, which acts as an emollient.
Manufacturing. The block flow diagram for manufacture
of the transdermal patch is shown in Figure 4. It is a batch
operation. First, the ingredients must be weighed and mixed.
The drugs are mixed with the adhesive. The appropriate mix-
ing time and impeller arrangement are estimated using typi-
cal chemical engineering principles.'8' Then, the mixture is
coated on the backing. Hexane is used as a solvent to help
lower the viscosity of the solution and to ensure a well-mixed
product. After coating, the hexane is evaporated and is sub-
sequently incinerated, because it was determined that there
was not enough hexane present to justify a recovery system.
Next, the release liner is added to sandwich the drug/adhe-
sive mixture. After inspection (as required by law) large sheets
are cut into 10 cm2 patches, packaged individually, and then
packaged again, three per carton. Finally, cartons of the three-
packs are packaged for distribution.
Part of the design involved identifying "good manufactur-
ing practices" in the pharmaceutical industry, which ensure
that the product is pure and free of contamination.
Economics. Students determined that the cost of manufac-
turing one patch is between $0.28 and $0.30, depending on
employee salaries and the plant location. The U.S. pharmacy
price for a similar, brand-name product is approximately $15
per patch. Since this product is to be a generic version, it was
assumed that its price would be about half of the brand-name
product. The markup at the pharmacy is assumed to be twice
the price for which it was purchased. Therefore, the estimated
manufacturer's patch price is $3.75. Selling the patches for
$3.75 per patch yields a net present value of $684 million
assuming a 10-year plant lifetime and a 15% before-tax rate


A ... goal is to make students realize that
they will have to continue learning new
material throughout their careers, and that
they have the ability to do so.


of return. No information was available from industry sources
to verify these assumptions or the resulting NPV estimate.
Mathematical Modeling. In the design of a transdermal
patch, the dose is a key factor to consider. The drug is deliv-
ered from the patch to the body by diffusion through the
multiple layers of skin, so students were required to model
diffusion through multiple, immiscible layers. The flux of a
given drug from a transdermal system into the body can be
modeled as shown in Figure 5a. The result is

Cn
Co n
j C MJ (1)
1 x-,n 1


K


n( n
Ku M
Sj-1 )


where CO is the concentration of the drug in the patch, K is
the inverse of the resistance to diffusion of the drug provided
by each skin layer, and M. is the partition coefficient of the
drug between a layer and the subsequent layer (M = Cj/C.).
It was found that the rate-limiting step is diffusion through
the stratum corneum layer. So, if it is assumed that the con-
centration in the blood is zero (Cn = 0), the model reduces to
Figure 5b, and Equation (1) becomes
j=CoKiM1 (2)
A pharmacokinetic model was also developed, which can
be used to predict the concentration of the active ingredients
in the blood. The model is illustrated in Figure 6, and the
equations are

dC1 -k1C1
dt V,

dC2 kC, -k2C2
dt V2
where C, is the concentration of an active ingredient in the
patch, k, is the elimination rate constant from the patch, V, is
the volume of the patch, C, is the concentration of the active
ingredient in the blood, k, is the elimination rate constant
from the blood, and V, represents the volume of blood in
which the drug is distributed. Students fit this model to pub-
lished data to determine the values of k, and k.[9, 10]
Multiscale Design. In terms of multiscale analysis, design
of a transdermal drug delivery system requires design from
the molecular scale through the macroscopic scale. These


Spring 2006










items are summarized in Table 2. At the molecular scale, the
drug itself is designed. This is beyond the scope of this project.
At either the molecular or nano scales, one finds the pres-
ence of excipients and/or enhancers in the patch. The adhe-


sive to hold the transdermal patch
to the skin could involve design
at multiple scales. Since the drug
is mixed with the adhesive, if there
were a molecular interaction be-
tween the drug and adhesive, it
would have to be understood. For
an adhesive to stick, it must wet
the skin, so an understanding of
colloid-scale wetting phenomena
is required. The patch must be re-
moved without significant dis-
comfort, yet not become detached
in the shower or during physical


DISCUSSION
One of the advantages of a project such as ice cream pro-
duction is that it has traditional chemical engineering com-
ponents (e.g., refrigeration cycle, wastewater treatment, steam


TABLE 2
Length Scales and their Application to
the Transdermal Patch Problem

nano scale the action of enhancers and excipients at
a molecular level on the skin surface
colloid scale mechanism of adhesion
transdermal transport phenomena
micro scale
pharmacokinetics
macro scale product manufacture


activity that causes sweating-both macro-scale phenomena.
At the microscopic scale, the mechanism of transport of the
drug through the skin must be understood. Modeling drug
transport through the skin layers is standard transport phe-
nomena. Similarly, there is system modeling, in which the
pharmacokinetics of the drug in the body can be modeled.
Finally, at the macroscopic scale, the components must
be combined appropriately, manufactured into the desired
product, and packaged for sale.

ASSESSMENT
Two assessment measures were used. In one, the two in-
structors use a rubric to evaluate, separately, all aspects of
the final design report and oral presentation submitted by the
students each semester. This rubric was developed in the con-
text of more traditional chemical engineering design prob-
lems. For example, since biology is not (yet) required in our
curriculum, it is not listed as a science that students are ex-
pected to demonstrate an ability to apply. The ability to learn
and to apply biological concepts as needed is evaluated un-
der the ability to learn new material not taught in class. The
complete rubric is available on the Web."" Table 3 shows the
results, averaged for the two instructors, for both projects.
The score of three indicates meets expectations, and the score
of four indicates exceeds expectations. Clearly, our assess-
ment of the students suggests that they exhibited superior
performance in the ability to teach themselves new material.
In our student evaluation of instruction, it is possible for
the instructor to add an individually defined question. Table
4 shows several such questions and the student responses.
The responses are on a 5-point Likert Scale, thus indicating
student responses were all between "agree" and "strongly
agree." Therefore, we conclude that the students involved in
these projects believed them to be beneficial.


the design. For example,


production) along with multiscale
considerations, product design and
manufacture, and packaging. De-
sign of a transdermal drug patch has
a stronger life science component
and involves more transport phe-
nomena-oriented mathematical
modeling (i.e., systems analysis)
than a traditional chemical pro-
cess design.
While the multiscale aspects of
these projects have been identified,
the molecular-scale phenomena
have not yet been incorporated into
we do not believe that we are in a


position to design a new drug or to manipulate the micro-
structure of ice cream. If, however, a product design assign-
ment were based on a faculty member's research, it might be
possible to include molecular-, nano-, or colloidal-scale de-
sign aspects, especially if students were in a position to per-
form experiments.
A reasonable question is what other design projects of this
type are envisioned. The list of potential life science-related
projects is long and could include innovative drug-delivery
devices (e.g., drugs on a chip) or tissue growth. Our class of
2003 designed a facility for the batch production of amino
acids.i'' Design of a microprocessor production facility would
involve multiscale phenomena and could also involve tradi-
tional chemical engineering in the production of ultra-pure
water and in wastewater treatment. Design of an advanced
material based on its micro- or nano-structure is also pos-
sible. The importance of multiscale phenomena in paper
manufacture was recently presented,'121 so manufacture of fine
paper products is a possibility.
More detailed synopses of these projects are available on
our design project Web site.'51 The final reports are also avail-
able to faculty members by contacting the authors.

CONCLUSIONS
As the profession of chemical engineering moves toward
product development and design and away from process de-
velopment and design, a new paradigm for chemical engi-
neering education is evolving, requiring a new generation of
capstone design projects. Two examples have been presented
here. In ice cream manufacture, multiscale considerations are
important, yet there are traditional chemical engineering com-
ponents included. Production of other food products involves


Chemical Engineering Education











many of the same considerations. In design of a transdermal
drug delivery patch, life science considerations, multiscale
factors, and systems modeling are required. Both involve as-
pects of product design. They also require manufacture and
packaging of unit items-topics traditionally foreign to chemi-
cal engineering education. As the chemical engineering cur-
riculum changes in response to the changes in our profes-
sion, similar design projects will find their way into capstone
experiences.

ACKNOWLEDGMENTS

The following students worked on the transdermal patch:
Matthew Anderson, Jeffrey Bickar, Gregory Hackett, Joseph
Kitzmiller, Lindsay Kruska, John Ramsey, Samuel Smith,
Craig Travis, Ugochi Umelo, Jennie Wheeler, and Clayton
Williams.
The following students worked on ice cream production:
Jess Arcure, Jon Baldwin, Benjamin Banks, Adam Byrd,
Timothy Daniel, Mariana Esquibel, Kyle Gallo, Lina Galvis,
Joseph Jones, Matthew Kayatin, Dennis Lebec, Daniel
Malone, Jonathan Miller, Joshua Mounts, David Newcomer,
Rebecca Orr, Coleen Pell, Michael Pfund, James Rhoades,
Joshua Rhodes, Rebecca Seibert, James Sims, Michael Velez,
William White, Jason Williams, and Joanne Winter.


Portions of this paper were presented at the 2004 ASEE
Annual Meeting, Salt Lake City, UT, session 3413
transdermall patch) and at the 2005 ASEE Annual Meeting,
Portland, OR, session 3113 (ice cream).

REFERENCES
1. Cussler. E.L.. and J. Wei. "Chemical Product Engineering." AIChE J.
49, 1072-1075 (2003)
2. Cussler. E.L., "Do Changes in the Chemical Industry Imply Changes
in Curriculum?" Chem. Eng. Ed.. 33(1) 12 (1999)
3.
4. Criteria forAccrediting Engineering Programs (2006-07 cycle), ABET,
Inc., Baltimore, p. 27
5.
6. Shaeiwitz, J.A., W.B. Whiting, and D. Velegol, "A Large-Group Se-
nior Design Experience: Teaching Responsibility and Lifelong Learn-
ing." Chem. Eng. Ed., 30(1), 70 (1996)
7. Turton. R., R.C. Bailie, W.B. Whiting, and J.A. Shaeiwitz, Analysis,
Synthesis, and Design of Chemical Processes, 2nd Ed., Chapter 24.
Prentice Hall PTR, Upper Saddle River, NJ (2003)
8. Oldshue, J., Fluid Mixing Technology, Chapter 15, McGraw Hill, New
York (1983)
9. Kydonieus, A.F, and B. Bemer, Transdermal Delivery of Drugs, Vol-
ume II. CRC Press, Boca Raton, FL (1987)
10. OrthoEvra Full Prescribing Information, Ortho-McNeil Pharmaceu-
ticals. Raritan, NJ (May 2003)
11.
12. Hubbe. M.A.. and O.J. Rojas, "The Paradox of Papermaking," Chem.
Eng. Ed.. 39(2). 146 (2005) 7


TABLE 3
Assessment Results for Design Projects

Assessment Patch Ice Cream

Design of equipment, understand interrelationship between equipment in process 3.0 3.0
Apply chemistry, math, physics. engineering science 3.5 3.5
Resolve complex problem into components 3.0 3.5
Apply economic, physical constraints, and optimization methods to obtain solution 3.0 3.0
Use of computer-based and other information systems 3.0 3.0
Demonstrate ability to learn new material not taught in class 4.0 4.0
Demonstrate ability to function in assigned role 3.0 3.0
Demonstration of ethical behavior 3.0 3.0
Demonstrate understanding of societal impact and need for assigned design 3.0 3.0


TABLE 4
Student Evaluation of Instruction Results

Result Group Out of
Asked 5.0

Tackling the nontraditional problem posed in the large-group project enhanced my confidence in solving new problems. Patch 4.90
I feel that my experience with the group design taught me the importance of and the need for continuously learning new material. Patch 4.17
In my career, I will be required to solve problems appearing to be outside the mainstream of chemical engineering, Ice cream 4.17
such as food processing.
I feel confident that I can apply my chemical engineering knowledge to any application. Ice cream 4.40
The teamwork experience in this class will be valuable in my future career. Ice cream 4.57


Spring 2006











Random Thoughts...




A WHOLE NEW MIND

FOR A FLAT WORLD



RICHARD M. FIELDER
North Carolina State University


Interviewer: "Good morning, Mr. Allen. I'm Angela
Macher-project engineering and human services at Con-
solidated Industries. "
Senior: "Good morning, Ms. Macher-nice to meet you."
I: "So, I understand you're getting ready to graduate in
May and you're looking for a position with Consolidated...
and I also see you've got a 3.75 GPA coming into this semes-
ter-vely impressive. What kind of position did you have in
mind?"
S: "Well, I liked most of my engineering courses but espe-
cially the ones with lots of mnali and computer applications-
I've gotten pretty good at Excel and Matlab and I also know
some Visual Basic. I was thinking about control systems or
design.
I: "I see. To be honest, we have very few openings in those
areas-we've moved most of our manufacturing and design
work to China and Romania and most of our programming
to India. Got any foreign languages?"
S: "Um, a couple of years of Spanish in high school but I
couldn't take any more in college-no room in the curricu-
lum."
I: "How would you feel about taking an intensive language
course for a few months and moving to one of our overseas
facilities? If you do well you could be on a fast track to man-
agement."
S: "Uh...I was really hoping I could stay in the States. Aren't


Richard M. Felder is Hoechst Celanese Pro-
fessor Emeritus of Chemical Engineering at
North Carolina State University. He received his
B.ChE. from City College of CUNYandhis Ph.D.
from Princeton. He is coauthor of the text El-
ementary Principles of Chemical Processes
(Wiley, 2005) and codirector of the ASEE Na-
tional Effective Teaching Institute.



Copyright ChE Division of ASEE 2006


any positions left over here?"
I: "Sure, but not like 10 years ago, and you need different
skills to get them. Let me ask you a couple of questions to see
if we can find a fit. First, what do you think your strengths
are outside of math and computers?"
S: "Well, I've always been good in physics."
I: "How about social sciences and humanities?"
S: "I did all right in those courses-mostly A's-but I can't
honestly say I enjoy that stuff."
I: "Right. And would you describe yourself as a people
person?"
S: "Um...I get along with most people, but I guess I'm kind
of introverted."
I: "I see ." (Stands up.) OK, Mr. Allen-thanks. I'll
forward your application to our central headquarters, and if
we find any slots that might work we'll be in touch. Have a
nice day."


This hypothetical interview is not all that hypothetical. The
American job market is changing, and to get and keep jobs
future graduates will need skills beyond those that used to be
sufficient. This message is brought home by two recent
books-Thomas Friedman's The World is Flat' and Daniel
Pink's A Whole New Mind--that I believe should be required
reading for every engineering professor and administrator.
The books come from different perspectives-the first eco-
nomic, the second cognitive-but make almost identical
points about current global trends that have profound impli-
cations for education.
An implication for engineering education is that we're
teaching the wrong stuff. Since the 1960s, we have concen-
trated almost exclusively on equipping students with analyti-


TA. Friedman, The World is Flat, New York, Farrar, Straus, & Giroair,
2005.
SD.H. Pink, A Whole New Mind, New York, Riverhead Books, 2005.


Chemical Engineering Education










cal (left-brain) problem-solving skills. Both Friedman and
Pink argue convincingly that most jobs calling for those skills
can now be done better and/or cheaper by either computers
or skilled foreign workers-and if they can be, they will be.3
They also predict that American workers with certain differ-
ent (right-brain) skills will continue to find jobs in the new
economy:
El creative researchers, developers, and entrepreneurs
who can help their companies stay ahead of the
technology development curve;
El designers capable of creating products that are
attractive as well as functional;
El holistic, multidisciplinary thinkers who can recognize
complex patterns and opportunities in the global
economy and formulate strategies to capitalize on
them;
El people with strong interpersonal skills that equip them
to establish and maintain good relationships with
current and potential customers and commercial
partners;
E people with the language skills and cultural awareness
needed to build bridges between companies and
workers in developing nations (where many manufac-
turing facilities and jobs are migrating) and developed
nations (where many customers and consumers will
continue to be located);
E self-directed learners, who can keep acquiring the new
knowledge and skills they need to stay abreast of
rapidly changing technological and economic
conditions.

Those are the attributes our students will need to be em-
ployable in the coming American engineering job market.
The question is, are we helping them to develop those at-
tributes? With isolated exceptions, the answer is no. We still
spend most of our time and effort teaching them to "Derive
an equation relating A to B" and "Calculate Z from specified
values of X and Y." We also offer them one or two lab courses
that call on them to apply well-defined procedures to well-
designed experiments, and we give them a capstone design
course that may require a little creativity but mostly calls for
the same calculations that occupy the rest of the curriculum.
Nowhere in most engineering curricula do we provide sys-
tematic training in the abilities that most graduates will need
to get jobs-the skills to think innovatively and holistically
and entrepreneurially, design for aesthetics as well as func-
tion, communicate persuasively, bridge cultural gaps, and
periodically re-engineer themselves to adjust to changing
market conditions.


Why don't we? It's because people as a rule don't want to
leave their comfort zones, and engineering professors are as
subject to that rule as anyone else. We are all comfortable
deriving and solving equations for well-structured single-dis-
cipline systems, but most of us are not so sure about our abil-
ity to handle ill-defined open-ended multidisciplinary prob-
lems or to teach creative thinking or entrepreneurship. So,
despite a crescendo of headlines and best-sellers about the
growing exodus of traditional skilled jobs to developing coun-
tries (including high-level research and development jobs,
which are increasingly moving to India and China4), many
engineering faculty members vigorously resist suggestions
to make room in the curriculum for multidisciplinary courses
and projects or anything that might be labeled "soft." Even
though most of our alumni in industry-95%? 99%?-as-
sure us (as they have done for decades) that they haven't seen
a derivative or integral since they graduated, the traditional-
ists still insist that we can only produce competent engineers
by devoting almost every course in the curriculum to deriv-
ing and solving equations, analytically and with Matlab. The
same professors are no less resistant to efforts to move them
away from the traditional "I talk, you listen" pedagogy toward
the active, cooperative, problem-based approaches that have
been repeatedly shown to equip students with the skills Fried-
man and Pink are talking about. (See bibliography on p. 113.)
So far we've gotten away with it, although sharply declin-
ing engineering enrollments in recent years should be a red
flag. We can't count on getting away with it much longer,
however. The relentless movement of industry to computer-
based design and operation and offshoring of skilled func-
tions and entire manufacturing operations is not about to go
away. On the contrary, as computer chips get faster and de-
veloping countries acquire greater expertise and better infra-
structure, the movement will inevitably accelerate. The Ameri-
can engineering schools that respond by shifting toward more
multidisciplinary problem- and project-based instruction-
the way Olin, Rowan, Rose-Hulman, the Colorado School of
Mines, and a number of others have already started to do-
will survive. The schools that try to stick with business as
usual may not. I

Ifyou don't think this is already happening in engineering, check out
a 2005 NAE Report called "Offshoring and the Future of U.S. Engi-
neering: An Overview," weblinkslMKEZ-6G6R4D?OpenDocument>.
e S. Lohr; "Outsourcing is Climbing Skills Ladder," New York Times,
Feb. 16, 2006. This article reports that of200 multinational corpo-
rations surveyed, 38% said they planned to "change substantially"
the worldwide distribution of their R&D work in the next three years
.. and this particular trend is still in its infancy.


Spring 2006


All of the Random Thoughts columns are now available on the World Wide Web at
http://www.ncsu.edu/effective_teaching and at http://che.ufl.edu/~cee/













Maintaining Connections with Undergraduates

Continued from page 83


requested to provide contact information for classmates
(e-mail addresses, cell phone numbers, etc.). If they were
uncomfortable doing this, they were asked to contact
classmates themselves and encourage them to contact
one of the faculty. This approach, along with posting a
request on the department's blog (see Professor
Ashbaugh's account), still only allowed direct contact
information to be gathered for about 50 percent of our
students. The junior and senior classes, however, had
set up their own Yahoo groups prior to the storm, which
meant departmental e-mails ultimately reached more
students. In one instance, a student posted faculty mes-
sages to a Web site the student had built specifically for
sharing department information with classmates. In ret-
rospect, gathering alternate contact information prior
to Katrina as a regular part of getting acquainted with
students would have allowed department outreach ef-
forts to be more effective after the hurricane.
Studentfeedback from phone conversations led to the
realization that our core course curriculum was aligned
with only a fraction of other chemical engineering pro-
grams. Our unique Practice School program during the
senior year'3' requires that most core courses be offered
a semester earlier than other programs. As a result, stu-
dents found it challenging to find the chemical engi-
neering courses they needed. Ofparticular concern were
the seniors and their need to complete a capstone de-
sign course before graduation. Within a day of recog-
nizing this issue, the consensus from the faculty was that
our process design course would be offered during the
spring semester. This information was quickly commu-
nicated to the seniors. The speed with which decisions
of this type were made and communicated ultimately
affected the options our students had during fall regis-
tration. Since Katrina made landfall the weekend be-
fore the semester started, however, even the best efforts
meant students began attending classes at other uni-
versities two to three weeks late.
Many students evacuated New Orleans without their
textbooks or notes. Because of the broad scope of most
capstone design courses, the most affected group was
those seniors who managed to enroll in this course. As
a result, the faculty member who would have taught this
course within our department during the fall semester
offered to provide supporting information from books
that the students owned but left in New Orleans.


Those students who attended other universities in the
fall were requested to send us the name of the university
and the courses for which they were registered. This pro-
vided a means of double checking what the student
thought was an equivalent core course. If the course was
not adequately equivalent, the student was quickly noti-
fied. Under the difficult circumstances, many students
pragmatically chose to take their remaining non-ChE
courses during the fall.
Near the end of September, the faculty began discuss-
ing the course schedule for the spring and Lagniappe
semesters. From the fall registration information pro-
vided by our students, it became evident that offering
all core courses during these two semesters would be a
requirement in order to keep the students on track. By
mid-October, a course schedule for both semesters had
been established which met this objective.
Registration for the spring semester at Tulane began
in early November Two weeks prior to registration, all
students were sent an e-mail requesting they update their
fall course-enrollment information. In this e-mail, stu-
dents were also informed that they would be able to con-
tact three departmental advisors (Drs. Mitchell, John,
and Prindle) by phone for advising assistance over the
five-day period just prior to the beginning of registra-
tion. This call center setup provided the students with
assistance in addressing their registration questions.
Since the university Internet and e-mail servers were
restored in mid-October, there was no problem contacting
all of our students using their university e-mail addresses.
The response to this request was substantially higher.
Several challenges had to be overcome in manning
the call center. Since the campus was closed and secu-
rity was tight, department offices could not be entered
without special permission. In addition, service to de-
partment phones was not activated until the second day.
Despite obstacles, the call center was ultimately suc-
cessful in providing students with assistance in address-
ing their concerns prior to registration.
All of these efforts in establishing and maintaining
the faculty-student connection were difficult under the
challenging conditions. We believe, however, that they
have forged even stronger ties between both groups. As
a result of these experiences, some students feel more
comfortable discussing problems with faculty. Faculty
interest in our students and their well-being has in-
creased as well. While both groups looked forward to
the start of the spring semester and a return to a sense
of normalcy, that normal state will be distinctly differ-
ent. And, in many ways, better. O


Chemical Engineering Education










INTRODUCTION
TO A SPECIAL SECTION ON THE

Patten Centennial Scientific Workshop:




THE NEXT MILLENNIUM


IN CHEMICAL ENGINEERING




CHRISTINE M. HRENYA
University of Colorado Boulder, CO 80309-0424
H. SCOTT FOGLER
University of Michigan Ann Arbor, MI 48109-2136


Over the past several years, a number of chemical
engineering programs around the country have been
honoring the 100-year anniversaries of their origins. The
2004-05 academic year marked a similar time at the
University of Colorado. In 1904-05, coursework for a
B.S. in chemical engineering included Slide Rule, Sur-
veying, Oil and Fuel Laboratory, and Heat Treatment
of Steel, whereas today's curriculum includes courses
such as Engineering Computing, Environmental Sepa-
rations, Polymer Science, Particle Technology, Tissue
Engineering, and Pharmaceutical Biotechnology. Simi-


lar-if not greater-
changes to the chemical
engineering discipline
are expected during the
next century.
To commemorate the
centennial year, a scien-
tific workshop dedicated
to discussions on the fu-
ture of the discipline was
hosted by the Department
of Chemical and Biologi-
cal Engineering at the
University of Colorado
on Feb. 3 and 4, 2005.
The participants included
Professors Kristi Anseth
(Univ. Colorado), Bob


Armstrong (MIT), Arup Chakraborty (UC Berkeley),
Ed Cussler (Univ. Minnesota), Mike Doherty (UC Santa
Barbara), Richard Felder (NC State), and Jerry Schultz
(UC Riverside)-see Figure 1, next page. The work-
shop consisted of two parts, namely oral presentations
and panel discussions. This feature section is intended to
share these exchanges with the greater ChE community.
In the first portion of the workshop, each of the seven
participants was asked to give an oral presentation on a
topic of his or her choice, with a theme that is both
broad in scope and forward thinking. An ordered list-
ing of the talks is given
4. Hrenya is an associate profes- in Table 1, next page.
ical and biological engineering at Corresponding written
ity of Colorado. She joined the fac-
eceiving her B.S. from The Ohio perspectives were re-
rsity and her Ph.D. from Carnegie quested of each partici-
'ersity. She has given over 50 in- prsptiv
is on her research in particle tech- pant; these perspectives
current emphasis of which is granu- are contained in the ac-
uidization, aerosol dynamics, and companying group of
iputational methods.
articles. The manu-
.D. from scripts cover pedagogi-
the Uni- cal issues (Professors
ntly the Armstrong and Felder),
guished
0e is au- a view on the current
reaction chemical industry (Pro-
rests are
kinetics, fessor Cussler), and
pharma- outlooks on emerging
aduated areas (Professors
areas.rty and S
Doherty and Schultz).


D Copyright ChE Division of ASEE 2006


Spring 2006 9


Christine f
sor of chen
the Universi
ulty after re
State Unive
Mellon Univ
vited lecture
nology, the
lar flows, fli
related conf

H. Scott Fogler. After receiving his Ph
the University of Colorado, he joined
versity of Michigan where he is curre
Ame and Catherine Vennema Distin
Professor of Chemical Engineering. H
thor of the text Elements of Chemical F
Engineering. His current research inter
in the areas of colloids, wax gellation
dissolution kinetics of zeolites, and the
cokinetics of acute toxicology. He has gr
36 Ph.D. students in these and related


Copyright ChE Division oj ASEE 2006











The Next Millennium in ChE


Figure 1.
Participants in the
Patten Centennial
Scientific Workshop-
University of Colo-
rado, February 2005.
Top row:
Arup Chakraborty,
Jerry Schultz,
Kristi Anseth.
Bottom Row:
Bob Armstrong,
Richard Felder,
Mike Doherty,
Ed Cussler.
Q AND A
The second portion of the workshop comprised two panel discussions, both of which were driven by questions from
the attending faculty and graduate students. A paraphrased overview of this exchange, grouped according to topic, is
given below. The respondents are indicated according to their initials (see Table 1). Since these discussions took place
after individual presentations, the reader may choose to read this portion after the ensuing manuscripts to keep the
chronology of the interactions intact.
Curriculum
Question (to BA): How do you envision the curriculum change you have proposed occurring (see related
perspective by Bob Armstrong)?
BA: I think we should start with a clean slate and start by adding back in the most important areas and then stop
adding when four years are full. I think the approach should not include adding more classes than we currently
have, as that will lead to an overcrowding of schedules and then the students would have no time to think about
what they are learning.

We have not changed the curriculum in the last 40 years due to the large research engine created after World
War II. Faculty were too busy with research to improve significantly the content in the classroom. Faculty have
to take time from research, for example to write textbooks or Web modules. We need to do this together as a
community of universities. You have got to reward faculty for implementing change.

EC: There is no way that we could possibly do what Bob is saying. Also, committee books are really bad
usually. I think modifications need to be done one course at a time. Let me liken it to the past when periodic
tables were put on the classroom walls. At that time, boiling points were the only important properties we

TABLE 1
Presentation Listing

Participant Title
Prof. Richard Felder (RF) Teaching Engineering in the 21st Century with a 12th-Century Teaching Model: How Bright is That?
Prof. Bob Armstrong (BA) A Vision of the Chemical Engineering Curriculum of the Future
Prof. Arup Chakraborty (AC) Quantitative Cellular and Molecular Immunology: A New Opportunity for Chemical Engineering
Prof. Jerry Schultz (JS) In Vivo Biolmaging: Advances and Challenges
Prof. Ed Cussler (ECY A Different Chemical Industry
Prof. Mike Doherty (MD) Crystal Engineering: From Molecules to Products
Prof. Kristi Anseth (KA) Chemical Engineering in 2020: Return of the J.E.D.I.?


100 Chemical Engineering Education










The Next Millennium in ChE


needed to know because everything was petrochemicals. Now, chemical engineers are using the information on the
periodic table.
Question: With all the changes and additions that have been suggested, do you think there will need to be a five-
year undergraduate degree? Or is it time that we separate the curriculum into new majors (e.g., tissue engineering,
metabolic engineering)?
RF: We cannot put in all the content, since the content is always changing. We have to emphasize how to learn,
skills, flexibility.
BA: You need to learn a good way of thinking-the courses are just vehicles. I think it is a mistake to fractionate
into subareas at the undergraduate level. As a career evolves you are always introduced to new areas, so you learn
to augment knowledge. Incidentally, the renaming of many departments that has occurred recently-to include
"bio" in their name-is very different than the splitting into subareas we are talking about. The inclusion of "bio" in
a department name reflects the change in our underlying molecular core science from chemistry alone to a combi-
nation of chemistry and biology.
EC: If you put in new material, you have to chop out fluff. We can do that by compressing courses (e.g., transport
phenomena). But we also need to adapt to what is relevant. For example, I think it is a tragedy that at Minnesota we
teach thermodynamics without covering the topic of ionic solutions, which has tremendous biological relevance.
KA: It is important to consider which industries we want to serve when implementing changes into our curriculum.
Textbooks
Question: A number of the items discussed thus far have been about modifying courses and teaching new courses.
One problem set I foresee is: Where are the textbooks, when will they come, and how will authors be rewarded?
MD: Scholars are responsible for writing research papers, books, patents, and grants. There is a need to de-
emphasize papers and make a global contribution like writing texts. It's so hard to write a book. Role models are
key-if role models write books then others will be written; if they don't, then there will be no books. A large
problem is that there is insufficient reward for writing texts. Nevertheless, academics should do it as part of their
job.
RF: It is hard to write books-hard and time consuming. Don't write a book before you have tenure. Rewards?
Don't do it for rewards. A book only counts as a publication and the effort it takes is the same as for 25-50 publica-
tions. Write it because you want to write it-it will be a better book if it's a labor of love.
BA: People need to step forward and do it-or at least convince others to do it. One reward is that the reputation of
the school gets better when books are written by faculty. The rewards are not well-translated to individual rewards.
One answer may be to get teams of faculty to write books. The books become much more interesting and have
broader perspective if they are done as truly collaborative efforts, and there's less work per person.
Role of Biology
Question (to JS): What do you see as the future for division of labor between materials science and bioengineering?
JS: We will have some aspects of materials science tailored to bioengineering. Why should a name be changed to
Biochemical Engineering? There was no change to Plastic Chemical Engineering when plastics were the popular
topic in chemical engineering. To be successful, engineering programs must collaborate with true biology pro-
grams. Also, engineers design new products based on physics, chemistry, and biology. Now that we can manipulate
biology, biology is becoming more quantitative.
Question (to AC): Did basic biology prepare you for the biological research you are undertaking?
AC: The curriculum Bob talked about is exactly what is required. Learn the general idea and work from the
molecular up to the macroscopic.


Spring 2006 101











The Next Millennium in ChE


Teaching Methods
Question (to RF): Do you believe distance learning is better? I'm asking about isolationism vs. learning in the
presence of other students?
RF: Compared with an active-learning class, distance learning is not better. There are some things technology can
never replace. I don't believe software will ever be able to motivate students. That's not to say we can't supple-
ment an active-learning classroom with technology.
Question: How should industry perspectives be incorporated into the undergrad classroom?
RF: Take industry problems and bring them into the classroom. Use a problem-solving method and let students
take the lead in making decisions.

JS: Bring in industry representatives to be a part of the design team and problem-solving effort. Use real corpo-
rate resources and financial support to solve real, relevant, industrial problems.
MD: From real-world consulting experience with DuPont, I understand that engineers typically have very short
windows in which to make decisions with limited information. It is important to develop skills to quickly and
hierarchically make these decisions. Each result should yield a "yes" or "no" response for continuing or changing
paths.
EC: Define complex problems and have some process for judging if a commercial product is likely to work.
Expose students to situations where they have to make decisions with limited data.
Enrollments / Future of the Discipline
Question: What is happening with ChE enrollments?
EC: Although we are seeing decreasing enrollments, we should look at the bigger picture. There has been an
increase of 50% in ChE programs and a decrease in enrollment-that makes sense. On my way here, I was doing
a little research and did you know that there are 11 Ph.D. programs in the state of Ohio-that's silly! I think it is
time to start killing programs for undergraduates and graduates.
BA: Undergraduate enrollment is on the increase again. In 2000, there were 6,000 undergraduates enrolling per
year. Enrollment since 1973 can be fit with a sine wave and seems to follow job growth. Times change. It is up to
educators to know what industries are growing/shrinking and make students aware of it. My concern is not so
much at the B.S. level as it is to where are all the Ph.D.s are going to go for jobs?
AC: Ph.D. enrollment is flat during the same time.
JS: In ChE, enrollment varies up to about 10% a year. The amount of high school graduates going into the field of
engineering, however, is about the same. It's all dependent on jobs.
Question: Say I am a high school senior who is really good at math and science. How would you convince me to
be a chemical engineer?
JS: Out of all engineering, chemical engineering has the widest range of basic science. Chemical engineering
offers students a good systems base for the next 30-50 years.
BA: Chemical engineering is preparation for a diverse range of career types.
MD: Our primary asset is that we can provide quantitative solutions. This differentiates us from chemists,
biologists, etc. With a ChE B.S., one can go out into the real world with a good-paying job. Chemists and biolo-
gists tend to have a more difficult time finding more challenging, higher-paying jobs at the B.S. level.
RF: This is the only discipline that can put together so many sciences. Chemical engineers can be found in many,
if not most, technical fields in industry. Also, most students don't know what they are interested in, so it keeps
doors open (e.g., environmental, heath care).


102 Chemical Engineering Education











The Next Millennium in ChE


Global Competition
Question: With the battle for global economy and our standard of living in jeopardy, what are your thoughts on
lower-cost plants and research moving to other countries? How do we innovate and bring new products/technolo-
gies to market quickly to win? What can faculty do?
BA: We need to teach our students marketing, how to identify real needs, and how to solve problems to meet
those needs. We can only succeed if we innovate-not by becoming a service-based country. One minus for the
United States is that our culture is not one that tends to save money. There are concerns that we will not have
money required for investment in R&D.
MD: There is a natural progression in history that the same main group of countries innovates, and the new
technologies/products become more commodity and move to other places, e.g., steel. In the 1880s, the 20 richest
places in the world included North America, Europe, and Australia. In the 1980s the list had not changed much,
with few exceptions, including the addition of Japan to the list. It is fairly hard to screw things up! Well-estab-
lished systems and stable governments lead me to believe things will remain the same.
Energy and Water Research
Question: In the next 50 years, what will be the biggest problem of the world and what role will chemical engi-
neers play in solving it?
EC: Energy and water. I do not think ChEs will dominate health care or food. Regarding water, ultrafiltration to
remove viruses is needed. Regarding energy, gas will cost $6 a gallon in 10 years. Because of that there will be a
renaissance to energy research. A hydrogen economy is controversial and nonsensical. Fuel cells will need a major
breakthrough, and one which is more applied in nature than universities are used to. Thus, universities won't
dominate fuel-cell research.
MD: Energy is a huge problem-a national strategic problem. The developing world, including India and China,
will increase the demand for energy. Two million cars were sold in China last year. In 10 years, there will be more
cars in China than in the United States. India will be much the same as China. Bombay today is wall-to-wall cars.
There will be a massive demand for energy, and not all will come from fossil fuels due to CO, problems. An H,
economy does not change that because H, is also from fossil fuels. The best prospect is nuclear energy. Also,
methane is a big area that needs research funding. Currently, nothing can be done with methane unless it is
compressed to LNG (liquefied natural gas). Right now, 4 billion cubic feet of methane is flared per year. That
amount of energy is equivalent to 300 million barrels of oil. If it were liquefied and consumed by offshore units,
the energy produced would be very useful. Methane can also be changed to other forms for transport but it is not a
priority to the government so success is slow coming. National governments need to make priorities, balancing
CO, generation, global warming, and the risks of nuclear energy. A succession of U.S. governments have had their
heads in the sand, which is a strategic mistake for this country.
BA: Hydrogen is only a carrier-the energy must come from some primary source such as nuclear. There is a
huge need for energy carriers for automobiles. Other areas of energy research include biomass and carbon seques-
tration so that CO, problems can be alleviated. There are, of course, many alternative energy sources including
solar (most expensive now), wind (farms are unpleasing aesthetically, but most economically sound right now),
and biomass (two times the cost of wind). We need a government willing to admit that energy is a problem and
then federal research money will be available. One really good way to get revenue for research is to tax gasoline at
something on the order of 10 to 50 cents per gallon.

ACKNOWLEDGMENTS
We are grateful to the numerous graduate students at the Department of Chemical and Biological Engineering at the
University of Colorado who volunteered their time and helped make this workshop possible. O




Spring 2006 103










SThe Next Millennium in ChE






A Vision of


THE CURRICULUM

OF THE FUTURE




ROBERT C. ARMSTRONG
Massachusetts Institute of Technology Cambridge, MA 02139


Over the past 40 years, the discipline of chemical en-
gineering has undergone dramatic changes. We are
no longer a discipline largely coupled to a single
industry, namely the petrochemical industry. Rather our gradu-
ates go to a wide variety of industries including chemicals,
fuels, electronics, food and consumer products, materials, and
biotechnology and pharmaceuticals.11
Moreover, the character of the chemical industry has
changed significantly, particularly in recent years:
F the chemical industry is today very much a global
enterprise;
F companies have been reshaped by a series of mergers,
acquisitions, and spin-offs;
l some major chemical companies have become life
science companies and spun off their chemical units;
F and the time-to-market for new products has been
significantly shortened.
Similarly, the research enterprise in chemical engineering
has exploded over the past 40 years both in dollar volume
and in breadth. The exciting research opportunities that we
explore today as a discipline were well illustrated in the "Fu-
ture of Chemical Engineering Research" sessions at the 2004
Annual Meeting of AIChE. Particularly notable shifts in re-
search over this period include much more biologically re-
lated research and a much stronger molecular perspective in
the research.
Over this same 40-year period the undergraduate curricu-
lum in chemical engineering has remained nearly unchanged.
The stagnation in the curriculum is well illustrated by Figure
1, which is taken from a paper by Olaf Hougen.121 The flow
chart in the figure shows the evolution of the curriculum de-
cade by decade from 1905 to 1965. In each decade, new con-


tent entering the curriculum is shown as well as material that
was removed in order to "conserve mass." The center of each
box defines a core themes) for the decade.
I would like to make two observations about this figure.
First, over the 60 years shown, the curriculum was very dy-
namic with significant changes in each decade. Second, by
1965 we had developed a curriculum for undergraduate edu-
cation that is very nearly the same as today's. Why is this? It
is possible that after 60 years of hard work on the curriculum
the discipline arrived at a more or less timeless implementa-
tion. But this seems hard to believe in the face of all of the
change that has taken place over the past 40 years outside of
the curriculum. On the other hand, it is possible that we have
simply not paid the attention we should to curriculum devel-
opment over this period. This is what I believe has happened.
This same period has seen an enormous growth in federal
research funding in universities, and this growth is reflected
in the large number of doctoral research programs in chemi-
cal engineering around the country. This research has created
valuable intellectual growth in our community, but it con-
sumes an enormous fraction of the time of our faculty mem-
bers just to keep the research engine running, with grant pro-


Robert C. Armstrong is Chevron Professor and head of the Depart-
ment of Chemical Engineering at the Massachusetts Institute of Tech-
nology. He received a B.ChE. from the Georgia Institute of Technol-
ogy in 1970, and a Ph.D. in chemical engineering from the University
of Wisconsin in 1973. His research interests lie in the areas of poly-
mer molecular theory, polymer fluid mechanics, rheology, multiscale
process modeling, transport phenomena, and applied mathematics.
He is co-author of the two-volume text Dynamics of Polymeric Liq-
uids, which has been named a Citation Classic.


Copyright ChE Division of ASEE 2006


Chemical Engineering Education














The Next Millennium in ChE)


INFLOW

TRANSPORT PHENOMENA
PHYSICAL MEASUREMENTS
DIFFERENTIAL EQUATIONS
COMPUTER PROGRAMMING

APPLIED KINETICS
PROCESS DESIGN
REPORT WRITING
SPEECH
INCREASE IN
PHYSICAL CHEMISTRY
UNIT OPERATIONS
ORGANIC CHEMISTRY
ChE THERMONDYNAMICS
PROCESS MEASUREMENTS
AND CONTROL
INCREASE IN
PHYSICAL CHEMISTRY
UNIT OPERATIONS
GENERAL CHEMISTRY
MATERIAL & ENERGY BALANCES
FUNDAMENTALS


UNIT OPERATIONS


INDUSTRIAL CHEMISTRY
METALLOGRAPHY
APPLIED ELECTROCHEMISTRY
TECHNICAL ANALYSIS
PYROMETRY
SHOPWORK
STEAM AND GAS TECHNOLOGY
CHEMICAL MANUFACTURE


PRINCIPAL
DEVELOPMENTS
ADE VI
TRANSPORT PHENOMENA
PROCESS DYNAMICS
PROCESS ENGINEERING
COMPUTER TECHNOLOGY

DECADE V

APPLIED KINETICS
PROCESS DESIGN
1945
DECADE IV

ChE THERMODYNAMICS
PROCESS CONTROL

DECADE III
MATERIAL AND
ENERGY BALANCES
DECADE II

UNIT OPERATIONS


DECADE I

INDUSTRIAL CHEMISTRY

I 9UO


OUTFLOW

GRAPHICS
[ SHOPWORK
REDUCTION IN
UNITOPERATIONS
MATERIAL AND
ENERGY BALANCES
INDUSTRIAL CHEMISTRY
METALLOGRAPHY
MACHINE DESIGN
STEAM AND GAS
TECHNOLOGY
REDUCTION IN
SSHOPWORK
INDUSTRIAL CHEMISTRY
- MECHANICS
STEAM AND GAS
A TECHNOLOGY
APPLIED
ELECTROCHEMISTRY
CONTRACTS AND
SPECIFICATIONS
--* REDUCTION IN
MECHANICS
MACHINE DESIGN
DESCRIPTIVE
GEOMETRY

HYDRAULICS
SSURVEYING
GAS MANUFACTURE &
DISTRIBUTION
FOREIGN LANGUAGES
REDUCTION IN MECHANICS &
QUANTITATIVE CHEMISTRY


Figure 1.
Changes
in a typical
undergraduate
chemical
engineering
curriculum
during 60 years.
The initial
curriculum
in 1905
consisted of
separate courses
in chemistry and
conventional
engineering.',3


posals, contractors' meetings, review panels, annual
reports, etc. The price has been neglect of the curricu-
lar content in chemical engineering and a widening
gap between the research done in modem chemical
engineering and the content taught in our undergradu-
ate programs.

The opportunities for chemical engineering today Che
are great (see Figure 2). We are uniquely positioned at
the interface between molecular sciences and engi-
neering, and this affords us many opportunities in a
broad range of technologies that lie at the interface
between chemical engineering and other science and
engineering fields. This image of chemical engineer-
ing creates a number of tensions in our curriculum.
There is a strong outward pull on our curriculum to- Fi
ward the many disciplines with which we interact at
the interfaces in Figure 2. The opportunity to teach
our students more about these particular areas of technology
is exciting educationally, but it does tend to have a fragment-
ing effect on the discipline. Opposing the strong outward pull
is an equally compelling need to look inward at the core of
chemical engineering. Some departments have dealt with this
tension by developing curriculum tracks in specialized ar-
eas. Students begin by taking a common core in chemical
engineering and then specialize in a number of technology
areas, e.g., biotechnology, materials. An alternative approach,


Materials
Science


Physics


Structured


Mathematics Computer
Science


Electrical
Engineering
Ironic


ion Mechanical
Engineering


Biology


Civil Engineering


chemistry A~
Cho


'gure 2. Chemical engineering has a special position between
the molecular sciences and engineering.


proposed here, is to refocus on the core content of chemical
engineering. Thinking clearly about what constitutes the core
of chemical engineering that will make our future graduates
key contributors in interdisciplinary problems is essential. It
is important to remember that the current core we teach was
developed when chemical engineering was described by the
horizontal axis in Figure 2. That is, chemical engineering was
dominated by the intersection of chemistry and mechanical
engineering. We need to reexamine whether that core is the


Spring 2006


S





WI











The Next Millennium in ChE


appropriate core for the two-dimensional image in Figure 2.
The broad range of applications of chemical engineering can
be included in the curriculum by way of examples, problems,



It is possible that after 60 years of hard
work on the curriculum the discipline
arrived at a more or less timeless imple-
mentation. But this seems hard to believe
in the face of all of the change that has
taken place over the past 40 years outside
of the curriculum.



case studies, and laboratories. In this way we maintain a com-
mon education for all chemical engineers that demonstrates
the versatility of the degree to all of our students.

CCR/NSF FRONTIERS IN CHEMICAL
ENGINEERING EDUCATION WORKSHOPS
The opportunities for reform in chemical engineering cur-
ricula are so compelling and broad that an appropriate re-
sponse requires wide-ranging participation across the entire
discipline. This is important for a number of reasons. First,
the opportunities/frontiers are too broad for any one depart-
ment or several departments to address effectively. Second,
the costs-time and money-of developing new educational
materials are too high for any of us to absorb alone. Finally,
the coherence resulting from a joint effort will serve the dis-
cipline well in maintaining a clear identity to the world (po-
tential students, industry, and government), ensuring good
manpower supply to industry and to our graduate programs,
and ensuring that curriculum developments are used.
Nearly 100 faculty members from 53 universities along with
industrial representatives from five different companies met
in a series of three workshops sponsored by the Council for
Chemical Research and the National Science Foundation to
discuss curricular opportunities and to map out a path for-
ward. Below I will highlight some of the key findings of the
workshops. I encourage you to look at the detailed work prod-
uct and proceedings from these workshops, which can be
found at .r 3
Before I begin with the summary of the workshop results,
I would like to relate an interesting observation made by many
of us at the workshops: if we think about the curriculum in
the large blocks we usually use-thermodynamics, transport
106


phenomena, kinetics, etc. -then change will be difficult or
impossible. The reason is very simple. The current curricu-
lum is full (or overflowing); if we take these large units to be
givens in a new curriculum, then there is simply no room for
new content. Hence we felt it worthwhile and important to
put everything on the table and to start with a clean slate in
thinking about the future. We asked ourselves, what should a
"Decade XI" box covering the years 2005 to 2015 look like
if we were to extend the Hougen analysis?
Principles
The first valuable lesson to emerge from the workshops
was a set of principles that captured well the consensus of
the group. These included:
F Changes in science and the marketplace call for
extensive changes to the chemical engineering
curriculum
B The enabling sciences are: biology, chemistry, physics,
mathematics
B There is a core set of organizing chemical engineering
principles
Molecular transformations, multiscale
analysis, systems
0 Molecular-level design is a new core
organizing principle
] Chemical engineering contains both product and
process design
B There is agreement on the general attributes of a
chemical engineer
Two of these elements need elaboration: the core organiz-
ing principles and the attributes of a chemical engineer.
Organizing principles
In order to arrive at a picture of the curriculum we began
by enumerating the content-rather than the labels-that
chemical engineering graduates should understand and be able
to use. By then looking at the linkages and interconnections
among these content elements, three organizing principles
for the chemical engineering curriculum emerged. These are
molecular transformations, multiscale analysis, and systems
analysis and synthesis.
At the heart of chemical engineering is the manipulation of
molecules to produce desired processes and products. This is
encompassed by the organizing principle of molecular trans-
formations. Our students must recognize by both qualitative
reasoning and quantitative computation that properties can
be changed by changing structure. Molecular changes can be
architectural, for example by forming or breaking covalent
bonds or by secondary or tertiary interactions to form super-

Chemical Engineering Education











The Next Millennium in ChE
s.__________________________________________


structures. Or molecular changes can be conformational, for
example in the orientation and stretching of polymer mol-
ecules to change mechanical properties or in the folding of
proteins. Chemical engineers need to understand the equilib-
rium properties of these molecular systems and the rates of
reaction or structural changes. Finally our graduates should
be equally comfortable with the manipulation of biological
molecules as with the small organic and large synthetic poly-
mer molecules that have been the traditional domain of chemi-
cal engineering.
It is not sufficient for chemical engineers to manipulate
matter at the molecular level. In addition we must be able to
connect behavior at the small scale with that at the large scale.


entire globe or large regions of the globe in which we desire
to regulate sources of emissions in order to control concen-
trations of undesirable chemical species.
In summary, chemical engineers leverage knowledge of mo-
lecular processes across multiple-length scales in order to
synthesize and manipulate complex systems comprising pro-
cesses and the products they produce. These new principles
are summarized in Figure 3.

Attributes
Engineers are fundamentally problem solvers, seeking to
achieve some objective of design or performance among tech-
nical, social, economic, regulatory, and environmental con-


For example, we
need to be able to
take the molecu-
lar-level under-
standing of the ki-
netics of a chemi-
cal reaction and
use this to design
an appropriate re-
actor for commer-
cial use. Or we
need to be able to
exploit the under-
standing of poly-
mer conformation
on properties in or-
der to design a
commercial spin-


* Molecular Scale Transformations
chemical & biological
physical: phase change, adsorption, etc
* Multi-Scale Descriptions
from sub-molecular through "super-macro"
for physical, chemical and biological
processes
* Systems Analysis & Synthesis
at all scales
tools to address dynamics, complexity,
uncertainty, external factors


Old core does
not integrate
molecular
concepts


Old core covers only
macro to continuum,
physical and
chemical


Old core primarily
tied to large scale
chemical processes


Figure 3. New organizing core principles for use in integrating the curriculum.


ning process to make high-strength fibers. The organizing prin-
ciple of multiscale analysis addresses the application of chem-
ical engineering principles over many scales of length and time.
It is not the goal of multiscale analysis to have students work
from the atomic or molecular level up to the macroscopic
level in every problem. Rather, it is important that students
develop the ability to recognize, in any given problem,
what the important length and time scales are for analysis
and design.
Ultimately chemical engineers cannot be successful unless
we can take the knowledge of molecular processes and the
ability to manipulate these across appropriate scales and in-
tegrate these into functional systems. The organizing prin-
ciple of systems analysis and synthesis deals with the tools
for synthesis, analysis, and design of processes, units, and
combinations of these. The systems of importance to chemi-
cal engineers cover a range of scales. They could be single
cells in which we manipulate and control metabolic pathways
to produce desired chemical products, or they could be the


straints. Chemical
engineers bring par-
ticular insights to
problems in which
the molecular na-
ture of matter is im-
portant. As educa-
tors we cannot teach
students everything
that might be en-
countered; instead
we aim to equip
graduates with a
confident grasp of
fundamentals and
engineering tools,
enabling them to
specialize or diver-


sify as opportunity and initiative allow. We seek in our cur-
riculum to develop critical thinking and problem solving
skills, especially for open-ended problems and those with
noisy data or uncertain parameters; to cultivate professional
attributes including oral and written communications skills;
to broaden the technical base of the students by including
examples from a variety of industries; and to cultivate an in-
stinct for lifelong learning and an awareness of the social
impacts of engineering and technology. The need for agile,
inquisitive, and fearless engineers is strongly reinforced in
the Molecular Frontier report on chemical sciences and en-
gineering,'4' which points out that the cutting-edge knowl-
edge of chemical engineering practice across industries is
changing constantly, as are global networks of technology
development.
In working to create a curriculum for the future, it is our
challenge to set a national vision for chemical engineer-
ing graduate practice beyond the norm, at the level de-
scribed by several national commissions on engineering


Spring 2006











The Next Millennium in ChE


education that envision engineering graduates who are
able to use fundamental knowledge of science and engi-
neering in a flexible and creative manner. The Molecular
Frontier report141 envisioned future graduates who can
meet the following challenges:
F Understand the basic chemistry of traditional
chemical processes, living systems, advanced
materials, and environmental control.
] Synthesize and manufacture any new substance that
can have scientific or practical interest, using
compact synthetic schemes and processes with high
selectivity for the desired product, and with low
energy consumption and benign environmental effects.
] Revolutionize design of chemical processes to make
them safe, compact, flexible, energy efficient,
environmentally benign, and conducive to the rapid
commercialization of new products.
F Understand and control, to the limits of current
knowledge and tools, how molecules react over all
time scales and the full range of molecular size.
F Develop unlimited and inexpensive energy, with new
ways of energy generation, storage, and transporta-
tion to pave the way to a truly sustainable future.
B Communicate effectively to the general public the
contributions that chemical engineering makes to
society.
F Be able to work in an interdisciplinary team of
scientists, engineers, and production personnel to
bring new substances from lab to production to
market.

A Draft Curriculum


The curriculum must engage stu-
dents in the subject matter of chemi-
cal engineering and its use, and culti-
vate along the way that mix of at-
tributes that characterizes the engineer.
To accomplish these goals we envision
a four-year structure that emphasizes
the themes of chemical engineering, in-
tegrates the contents of these themes
into a flexible and strong understand-
ing, and exercises the skills we want
to develop. This structure is versatile,
admitting a variety of materials and
modes of presentation, and is thus
adaptable to a range of cultures, re-
sources, and facilities found among
chemical engineering departments.
I do not have a finished structure of


Freshman


a curriculum to present; we are not yet that far along. At the
third workshop held on Cape Cod, however, we developed a
draft curriculum as a "proof of concept" to convince our-
selves that this was possible. Shown in Figure 4 is the layout
for a curriculum that develops the three organizing prin-
ciples-molecular transformations, multiscale analysis, and
systems analysis and synthesis-in parallel throughout the
undergraduate years, and shows how the three themes are
integrated in chemical engineering practice.
The content must also be integrated horizontally through
time, so that each principle is clearly developed. It is impor-
tant to provide many opportunities for repetition of key
ideas, concepts, and tools as the students move through
the four years of curriculum. The reinforcement of these
key elements should also be accompanied by a systematic
movement from simple to complex topics as the curriculum
proceeds. Content must also be integrated vertically at given
times in order to avoid compartmentalization. One way to
achieve this vertical integration is to use part of each year
for case studies, projects, or laboratories that cut across
the three themes. For example, each theme in the core
curriculum could be presented in one-and-a-half-semes-
ter subjects. In the latter half of the spring semester each
year, students could work in teams on intensive, integrated
laboratory or design projects that enable them to take the ma-
terial learned that year and apply it in projects developed by
industry/academic project members. In this way, both the
teaching and learning of the integrated core would be ad-
dressed. Integration could be further enhanced by a small-
group seminar series (possibly appended to an existing sub-
ject) that develops important abilities of social awareness,


Soph


Junior


Senior


Enabling Molecular-Scale Transformations
Courses Molecular Basis Molecular Basis of Reactions Special Topics
of Thermo Molecular Basis of Properties (Electives)
- Physics Classfctn of Molecules and Constitutive Eqns
- Chemistry
- Biology :
-Math Multi-Scale Analysis Beaker to Plant:
- Mat'ls Sci Interfaces and Assemblies Multi-Scale Descriptions Principles of Product &
- Eng/Comm Homogeneous Reactor Eng of Reactive Systems Process Des.
- Bus/Mgt


Chem Eng: Intro to Systems
The Frosh


Systems
Intro to Molecular Systems


Systems &
The Marketplace


Experience l

Figure 4. An example layout of a curriculum.


Chemical Engineering Education











The Next Millennium in ChE


professional ethics, communication, business development
and professional practice, and economics. By focusing each
seminar series on these important nontechnical abilities, stu-
dents would hone these skills and be better able to apply them
as part of their spring semester integrated project work.
In summary, the material within an academic term, as well
as across the four years, must proceed from simple to com-
plex. Fundamentals must be illustrated with applications, and
examples must range from the simple demonstration to the
challenge of complex design or system manipulation. Finally,
students must be engaged actively with this material. At the
end, the curriculum must add up to a complete picture of
chemical engineering. The detail given in each principle block
suggests an order of topics. Detailed definition of these blocks
is the subject of ongoing workshops.

CONCLUDING REMARKS
This paper proposes a vision for chemical engineering edu-
cation for the future-for 2015 and beyond. To return to the
Hougen analysis of the chemical engineering curriculum
shown in Figure 1, I am suggesting a structure and focus for
Decade XI as illustrated in Figure 5. Because we have not
engaged in substantial curriculum revision in 45 years, I be-
lieve that we are best served by beginning with a clean slate.
For outflow, I suggest the entire current curriculum. This is
not to say that there are not key elements of what we teach
today that should be retained, but rather everything in the
existing curriculum must compete with new ideas to win a
spot in the new curriculum. As illustrated in the figure, the
Decade XI curriculum would be organized around the orga-
nizing principles of molecular transformations, multiscale
analysis, and systems analysis and synthesis.


INFLOW


Molecular
engineering
Systems analysis [
Biology
Product


PRINCIPAL
DEVELOPMENTS

2015

DECADE XI

Molecular transformations
Multi-scale analysis
Systems view

2005


OUTF


Figure 5. The proposed extension to Hougen's chart.


This radically different curriculum would produce more
versatile chemical engineers, who are needed to meet the chal-
lenges and opportunities of creating products and processes,
manipulating complex systems, and managing technical op-
erations in industries increasingly reliant on molecular un-


The opportunities for reform
in chemical engineering curricula are
so compelling and broad that

an appropriate response requires

wide-ranging participation
across the entire discipline.


derstanding and manipulation. Another benefit of the new
curriculum is that it reconnects undergraduate education with
ongoing research in chemical engineering in a way that has
not been present for the past 40 years. This reconnection will
serve us well as an engineering discipline in attracting the
best and brightest students and in reopening the path to con-
tinual renewal of the curriculum.

ACKNOWLEDGMENTS
In writing this paper I have drawn very heavily on the col-
lective thinking at the Frontiers Workshops. It is impossible
to emphasize too strongly how much we have to learn from
one another as we move forward in this great adventure. I
want to give special thanks to the participants who synthe-
sized summary reports at each of these workshops-Nick
Abbott, Jeff Reimer, Jim Rawlings, Mike Thien, Greg McRae,
and Bill Green-and to Barry Johnston, who pre-
pared all of the material for the Frontiers Web site
including the excellent executive summaries. Finally
I thank Jeannette Gerzon who has ably helped or-
ganize and facilitate these workshops to help us
LOW be productive.

REFERENCES
1. AIChE Career Services, Initial Placement Survey. Data
shown are from 2003; similar data for 2002 are accessible at
placement.htm> (2003)
2. Hougen, O.A., "Seven decades of chemical engineering,"
Chem. Eng. Prog. (1977)
3. Proceedings of CCR/NSF Workshops on Frontiers in
Chemical Engineering Education, riculum/> (2003, 2005)
4. NRC, National Research Council, Board on Chemical Sci-
ences and Technology, Beyond the Molecular Frontier;
Challenges for Chemistry and Chemical Engineering, Na-
tional Academies Press (2003) 0


0
.2
co
c-
a
0- c
E o



CD
a C


Spring 2006










SThe Next Millennium in ChE












TEACHING ENGINEERING

IN THE 21ST CENTURY

WITH A 12TH-CENTURY TEACHING MODEL:



HOW BRIGHT IS THAT?







RICHARD M. FIELDER
North Carolina State University Raleigh, NC 27695-7905


If you took a stroll down a hall of the University of Bolo-
gna in the 12th century and looked into random door-
ways, you would have seen professors holding forth in
Latin to rooms full of bored-looking students. The profes-
sors would be droning on interminably in language few of
the students could understand, perhaps occasionally asking
questions, getting no responses, and providing the answers
themselves. You might see a few students jotting down notes
on recycled parchment, a few more sneaking occasional bites
of the cold pizza slices concealed in their academic robes,
some sleeping, and most just staring vacantly, inwardly curs-
ing the fact that iPods would not become readily available
for another 800 years. Toward the end of the lecture, one stu-
dent would ask "Professore, siamo responibili per tutta questa
roba nell'esame?" and that would be the only active student
involvement in the class. Eventually the class would be re-
leased, and the students would leave grumbling to each other
about the 150 pages of reading assigned for the next pe-
riod and expressing gratitude for the CliffsNotes version
of the text.


American engineering education doesn't exactly follow that
model. For one thing, the only engineering professor in the
Western Hemisphere-and maybe in the world-who could
lecture in Latin was Rutherford Aris, and he's deceased. Hard
drives have replaced parchment, baseball caps and jeans have
replaced caps and gowns, and (this is a huge difference) stu-
dents in Bologna actually had a lot of power, including the
responsibility of hiring professors and the right to fire them
if their performance was considered unsatisfactory. Leaving
those differences aside, however, the fact is that things haven't
changed all that much since the 12th century. If you walk
down the hall of an early 21st-century engineering school
and look into random doorways, there's a good chance you'll
see the descendants of those Bolognesi staring vacantly,

Richard M. Felder is Hoechst Celanese Professor Emeritus of Chemi-
cal Engineering at North Carolina State University. He received his
B.ChE. from City College of CUNY and his Ph.D. from Princeton. He
is coauthor of the text Elementary Principles of Chemical Processes
(Wiley, 2005) and codirector of the ASEE National Effective Teach-
ing Institute.


Copyright ChE Division of ASEE 2006
Chemical Engineering Education










The Next Millennium in ChE


snacking, and sleeping as their professors drone on inces-
santly in what might as well be Latin and fill the board or
projector screen with Latin and Greek symbols that have little
or no obvious relevance to anything the students know or
care about.
Twenty years ago that's all you would have seen in those
classrooms, with very few exceptions. Now, however, in some
departments at some schools you can find a significant num-
ber of classrooms in which other things are happening. You
might get the first signal of a difference before you ever get
to the doorway, when from down the hall you hear things
that are never heard in a traditional engineering classroom-


sounds of conversation, discussion, and argu-
ment, possibly punctuated by laughter, alter-
nating with periods of silence. If you look into
the room for awhile you would see traditional
classroom moments alternating with brief pe-
riods in which students are doing things indi-
vidually or in pairs or small groups-answer-
ing questions, completing the next steps of
derivations or problem solutions, troubleshoot-
ing, predicting, estimating, critiquing, inter-
preting, modeling, designing, formulating
questions, and summarizing. At any given mo-
ment the professor might be in front of the class
lecturing and answering questions, or quietly
observing the activity, or wandering around
the room interacting with individual students
and student groups. Unlike the situation in the
traditional classroom, many people-includ-
ing the professor-would appear to be enjoy-


only occur when the students had established a need to know
something to progress with their work.
So why the change? What is the answer to the traditional
professor's traditional defense of tradition: "It's been done
this way for decades or centuries and has worked fine," or
implicitly, "This is how I was taught, and look how well I
turned out!"
There are several answers, which would take much longer
to present completely than I have in this little piece, so I'll
only give brief suggestions of what they are and point to ref-
erences where the whole story can be found. First, if "work-


If you
have been
firmly
entrenched
in the
traditional
paradigm
I would
encourage
you to try
branching out,
but I would also
suggest taking
it easy.


ing themselves. Also unlike the traditional classroom, most
of the students enrolled in the course would actually be there.
If you inquired further into how courses are run in that de-
partment, you would see further evidence of two competing
models-one that would seem familiar to our 12th-century
scholars and one dramatically different. In one set of courses,
the professor would spend a great deal of class time lecturing
on the basic facts, formulas, and problem-solving algorithms
that comprise the course material, and would then give as-
signments and tests calling on the students to demonstrate
their ability to recite the facts, execute the formulas, and imple-
ment the algorithms. In the other courses, the students would
be presented with problems before they are told everything
they need to know to determine the solutions. They would
then work-sometimes individually and sometimes in
teams-to identify what they know and what they need to
find out, do research, formulate and test hypotheses, and ar-
rive at solutions. The professor would still be there to pro-
vide information and guidance, but formal instruction would


ing fine" means turning out excellent engineers
who have made brilliant creative contributions
to industry and society, that has certainly hap-
pened over the centuries. The issue, however, is
whether it happened because of traditional higher
education or despite it. There is compelling evi-
dence that the latter may be the case. Take Eu-
rope, for example. In the traditional European
system of higher education that has prevailed for
centuries, the professor is a godlike figure who
lectures to students and has little or nothing more
to do with them. The students may or may not
choose to attend the lectures-if the professor is
a particularly skilled lecturer they attend, other-
wise most don't.
You might argue that this system led to the
wondrous scientific advances of the Renaissance
and the Enlightenment and the giant technologi-
cal leaps of the industrial revolution, but I would


quarrel with that argument. If you admit only the cream of
the crop of a nation's youth (which universities in Europe
and America did until fairly recently), it almost doesn't mat-
ter what you do or don't do in the classroom. You could sim-
ply hand out syllabi and lists of references and tell the stu-
dents that they will be examined at the end of the year, and
then do nothing else-no lectures, no homework, no tests
except the final exam-and most students would manage to
learn the material and pass the exam, and the few geniuses
among them would go on to make their brilliant contribu-
tions, especially if they were clever enough to apprentice
themselves to masters from the previous generation.
In short, professors who provide only traditional lecture-
based instruction are largely irrelevant to the real learning
process for top students. Good lecturers can certainly enrich
their classroom experience, but they will learn with or with-
out that enrichment. On the other hand, if you are trying to
educate a broad segment of the population-as we are now
doing in the United States-many students can't make it with


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The Next Millennium in ChE


only the support that traditional instruction provides, and the
consequence is the attrition of 50% and higher that we rou-
tinely see in engineering.
Another argument for change is that unlike our anteced-
ents in the Middle Ages, we now know a lot from cognition
research about how people learn and the instructional condi-
tions that facilitate learning [see the reference by Bransford,
et al., in the bibliography], and everything we know supports
the proposition that the traditional lecture-homework-test
paradigm of engineering education is simply ineffective-
good students learn despite it, and weaker students who could
make excellent engineers frequently cannot survive it. The
alternative instructional environment supported by the re-
search is quite different. Here are some of the things teachers
do in that environment, contrasted with what they do in the
traditional approach.
T T: (Traditional) Establish a syllabus assuming
that all necessary prerequisite knowledge is
known, and march through it.
A: (Alternative) Find out at the beginning of a
course what most of the students know and don't
know and what misconceptions they have about
the subject, and start teaching from that point.
(This approach is known as constructivist
teaching.)

F T: Assume all students with the ability to
succeed in the profession for which they are
being educated are basically alike (specifically,
like the professor) and learn in the same way,
and teach accordingly.
A: Recognize that good students vary consider-
ably in motivation, cultural background, inter-
ests, and learning style, and teach accordingly.

I T: Focus on facts, formulas, and algorithms for
solving well-structured closed-ended single-
discipline problems.

A: Supplement the traditional content with
training in critical and creative thinking, meth-
ods of solving ill-structured open-ended multi-
disciplinary problems (which tend to be what
practicing engineers spend most of their time
dealing with), and professional skills such as
communication, teamwork, and project manage-
ment.

I T: Cover basic knowledge (facts, algorithms,
and theories) in lectures, then assign problems


that call for implementation of the knowledge,
then illustrate the knowledge in laboratories.

A: Recognize that students learn best when they
perceive a need to know the material being
taught. Start with realistic complex problems, let
students establish what they know and what they
need to find out, and then guide them in finding
it out by providing a combination of resources
(which may include mini-lectures and integrated
hands-on or simulated experiments) and guid-
ance on performing library and Internet research.
This is inductive teaching and has a number of
variations, including problem-based learning,
project-based learning, guided inquiry, discovery
learning, and just-in-time teaching.

I T: In class, present information, derive formulas,
and illustrate problem-solving procedures in
lectures, boardwork, and overheads or
PowerPoint images, occasionally asking
questions and responding to questions stu-
dents might ask.
A: In addition to lecturing, have students work
individually and in small groups on brief course-
related activities, such as answering questions,
setting up problem solutions, completing steps in
derivations, interpreting observations or experi-
mental data, estimating, predicting, brainstorm-
ing, troubleshooting .... Call on several
students for responses at the conclusion of each
activity, then invite volunteers to provide more
responses to open-ended questions, and proceed
with the lesson when the desired points have
been made. This is active learning.

I T: Require students to do all of their work
individually.

A: Assign a combination of individual work and
teamwork, structuring the latter to provide
assurances of individual accountability for all the
work done and following other procedures
known to promote good teamwork skills
(including communication, leadership, project
management, time management, and conflict
resolution skills). This is cooperative learning.

I T: Tell the students they are responsible for
everything in the text, lectures, and homework,
and make up exams that draw on those sources,
including some problems with twists that the


Chemical Engineering Education











The Next Millennium in ChE


students have not seen before and have to figure
out on the spot. (Those problems are there to see
if the students "know how to think.") It is up to
the students to guess what the instructor thinks is
important enough to include on a test.

A: Write comprehensive instructional objectives
that list the things the students should be able to
do (identify, explain, calculate, model, design,
critique ... ) to demonstrate that they have
satisfactorily mastered the knowledge and skills
the instructor wants them to master, including
high-level thinking and problem-solving skills.
Make the objectives available to the students,
ideally in the form of study guides for tests.
Design in-class activities and homework to
provide practice in the desired skills, and make
the tests specific instances of a subset of the
instructional objectives.

Instructors who are unfamiliar with the latter approach
imagine that they will have to list thousands of objectives
to be comprehensive, but this is not the case-a two-sided
sheet of paper is normally sufficient to list all of the ob-
jectives that might be drawn upon to construct a
midsemester test.

Entire articles and books can be-and have been-written
on each of the given alternative teaching methods, describ-
ing how to implement them and summarizing the research
base that demonstrates their superiority to the traditional ap-
proach. The bibliography at the conclusion of this paper sug-
gests starting points for interested readers.

If you have been firmly entrenched in the traditional para-
digm I would encourage you to try branching out, but I would
also suggest taking it easy. Going directly from a traditional
teaching model to a full-bore active/cooperative/problem-
based learning paradigm starting next Monday is probably
not a good idea-the amount of preparation required and the
student resistance that might erupt could be overwhelming.
Better approach is to make the change gradually, perhaps
by doing a few small-group exercises in lectures, using a
problem-based approach to teach one or two topics, and
writing instructional objectives for one midterm test. In
subsequent courses, increase your use of the new meth-
ods, never departing too much from your comfort zone,
and you should see your students' learning steadily increas-
ing. After all, it took us 800 years to get from Bologna to
where we are now; if it takes you a few years to get where
you want to be, the sky won't fall.


BIBLIOGRAPHY
Effective Teaching Methods and the Research that
Supports Them
1. Bransford, J.D., A.L. Brown, and R.R. Cocking, eds., How
People Learn: Brain, Mind, Experience, and School, Wash-
ington, DC: National Academy Press, 2000. Online at www.nap.edu/html/howpeoplel/>
2. Felder, R.M., D.R. Woods, J.E. Stice, and A. Rugarcia, "The
Future of Engineering Education: 2. Teaching Methods that
Work," Chem. Eng. Ed., 34(1), 26-39 (2000). Online at /www.ncsu.edu/felder-public/Papers/Quartet2.pdf>
3. Woods, D.R., R.M. Felder, A. Rugarcia, and J.E. Stice, "The
Future of Engineering Education: 3. Developing Critical
Skills," Chem. Eng. Ed., 34(2), 108-117 (2000). Online at

Active Learning
4. Felder, R.M., "Random Thoughts" columns in Chemical En-
gineering Education:
(a) "Learning by Doing," public/ColumnslActive.pdf>
(b) "It Goes Without Saying," felder-public/Columns/WithoutSaying.pdf>
See also CooperativeLearning.html>
5. Prince, M., "Does Active Learning Work? A Review of the
Research," J. Engr. Ed., 93(3), 223-231 (2004)
Cooperative Learning
6. Felder, R.M., and R. Brent, Cooperative Learning in Techni-
cal Courses: Procedures, Pitfalls, and Payoffs, www.ncsu.edu/felder-public/Papers/Coopreport.html>. See
also < h ttp : // w w w. n csu edu fielder -p ubic
Cooperative Learning.html>
7. Two meta-analyses of research on cooperative learning vs. tra-
ditional instruction can be found at
(University of Minnesota) and

(University of Wisconsin)
8. A Web site with links to CL-related papers and many CL sites
is Ted Panitz's
Problem-Based Learning
9. Prince, M.J., and R.M. Felder, "Inductive Teaching and Learn-
ing Methods: Definitions, Comparisons, and Research Bases,"
J. Engr. Ed., in press (2006)
10. Duch, B.J., S.E. Groh, and D.E. Allen, The Power of Problem-
Based Learning, Sterling, VA: Stylus (2001)
11. University of Delaware Problem-Based Learning Clearing-
house, . Ted Panitz's site
() and Deliberations, a site
managed by London Metropolitan University ( www.londonmet.ac.uk/deliberations/problem-based-learning/>)
are good sources of both information about PBL and links to
other PBL-related sites. O


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The Next Millennium in ChE


A DIFFERENT


CHEMICAL INDUSTRY





E.L. CUSSLER
University of Minnesota Minneapolis, MN 55455


An Altered Industry. The chemical industry today is
completely different from the chemical industry of
25 years ago. The clearest evidence comes from the
jobs taken by graduating chemical engineers. Twenty-five
years ago, 80 percent of these graduating students went to
the commodity chemical industry, exemplified by Dupont,
Exxon, Shell, and Dow. Occasionally they went to interna-
tional companies such as Bayer and ICI, though this was less
common. The remaining 20 percent were roughly divided
into equal groups. Some, perhaps 10 percent, went to prod-
uct-oriented businesses such as PPG, Upjohn, or 3M. A simi-
lar number, perhaps another 10 percent, went to everything
else, including consulting, government, and academia. This
older chemical industry, dominated by large-commodity
chemical companies, was very familiar and dependable.
Today, as Figure 1 shows, the situation is completely dif-
ferent. The percentage of graduates going to the commodity
chemical companies has dropped dramatically, perhaps to a
quarter of the total. Simultaneously, the percentage going to
consulting has risen to around another quarter. This consult-
ing includes functions such as process engineering, now con-
tracted out rather than performed within the engineering labo-
ratories of the commodity chemical companies.
The bulk of new graduates, however, now goes to indus-
tries where products are most important. Some of these prod-
ucts, such as pharmaceuticals, are familiar; others, such as
foods, have existed previously but have not involved signifi-
cant numbers of chemical engineers; still others such as elec-
tronics represent new efforts.

WHAT PRODUCTS ARE IMPORTANT
In this altered chemical industry, we must first ask what
are the products that we are going to produce. I believe there
are three types of these products, each with different charac-
teristics. The first and most obvious are the familiar com-


modities-the same products which used to dominate the
chemical engineering enterprise. The key for producing these
new products is their cost. Styrene produced by Dow and
styrene produced by BASF are chemically identical; the
issue is who can produce large quantities at the lowest
possible price.
The second and third types of products may be less famil-
iar. The second type involves molecules with molecular
weights of 500-700 and with specific social benefits. The most
obvious examples are pharmaceuticals. The key to the pro-
duction of pharmaceuticals is not their cost but rather their
time to market, i.e., the speed of their discovery and produc-
tion. The first-to-market tends to get at least two-thirds of the
eventual sales for the molecule, even after patents on the par-
ticular molecule expire. These products are normally not made
in dedicated equipment but rather in whatever reactors are
available at that specific time. Thus, process optimizations
tend to be less important than questions of scheduling: If the
equipment is being used for many different products, when
can you get in to make yours?
The third product type includes those for which the value
is added by processing to make a specific nanostructure. The
key to these products is their function. For example, I don't


Edward L. Cussler, currently distinguished institute professor at the
University of Minnesota, received the B.E. with honors from Yale
University in 1961, and his M.S. and Ph.D. in chemical engineering
from the University of Wisconsin in 1963 and 1965, respectively
Soon after, he went to teach in the Department of Chemical Engi-
neering at Carnegie Mellon University. In 1980, Cussler joined the
faculty at the University of Minnesota. He is the author of Multicom-
ponent Diffusion, published in 1976, and Diffusion, published in
1984 with a second edition published in 1997 He is the co-author of
Membrane Separation Systems, Bioseparations, and most recently,
Chemical Product Design, the English edition of which was published
in 2001.

Copiright ChE Division of ASEE 2006


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The Next Millennium in ChE


care why my shoes shine after I have applied polish; I only
care that they do shine. It is the shine, not the molecule that
produces the shine, that is important. Customers are often
willing to pay a premium for such a function, be it in a coat-
ing, in a food, or in a cleaner.
I find it helpful to think about these three types of products
using the summary shown in Table 1. For commodity prod-
ucts, the key factor as stated previously is the cost of the prod-
uct. The basis for producing the product will continue to be
unit operations-unit ops-the familiar core of chemical en-
gineering. Our action in this area should be to sustain the
commodity industry. We are certainly not currently carrying
out unit operations in the best way possible, but we are prob-
ably close to the limit of what is economically attractive.
With the key factor of the second type of molecular prod-
ucts being time to market, the major cost of products of this
type, such as drugs, is not the process engineering but the
cost of their discovery. At best, only one in a thousand drug
candidates is commercially successful. This enormous drop-
out rate is the reason drugs are expensive. The key to discov-
ery normally comes from chemistry and microbiology, not
from chemical engineering. As a result, it is not clear whether
traditional process engineering has a major role to play in
molecular products.
For nanostructured products, the third type, whose key fac-
tor comes from their superior function, the added value comes
from the process rather than from the chemical synthesis.
Their desired function is the shine of the polish or the clean-
ing of the detergent. Studies in this area seem to lack any
unifying intellectual core. Flavor release in food science takes
no advantage of what is known about controlled drug release
in pharmaceutics. Micelle formation in latex paint is an inde-
pendent topic from micelle formation in detergents. I believe
there is a genuine need for a general theory of nanostructured
products. Such a theory could be part of a required course
common to departments including chemical engineering, food
science, and pharmacy.

IMPLICATIONS FOR EDUCATION
Faced with this altered chemical industry, we must ask
whether the skill set currently mastered by chemical engi-
neers is appropriate for the future. This skill set consists of
three roughly equal parts, based in physics and mechanics, in
chemistry and biology, and in chemical engineering. I don't
think this skill set is inappropriate for the future. The ideas of
reaction engineering and separation processes will continue
to be central to what chemical engineers do. Within these
areas, some topics will recede and other topics will become
more important, but the core will remain.


E Commodities 0 Products ] Consult



Figure 1. Where the jobs are in chemical engineering.

I do think that there may be a partial problem with the
courses that present these topics. At the moment, these courses
are biased heavily toward the commodity chemical industry.
This bias includes such classical chemical engineering courses
as transport phenomena and thermodynamics. In the future,
new courses, including those based on biology, on polymer
science, and on product design, must become more central to
the chemical engineering curriculum. We require three such
courses at the University of Minnesota precisely because we
believe the content of those courses will better prepare our
students for the new chemical industry.
Some may find this description of a changed chemical in-
dustry depressing. I don't. I think it is simply different. For
example, it means that we may now work more on crystalli-
zation and less on fugacity, but I don't think that is a prob-
lem. In many ways, the reemergence of an emphasis on prod-
ucts and the corresponding de-emphasis of a few commodity
chemicals suggests a broader intellectual challenge for chemi-
cal engineering. That challenge is interesting. I welcome it. I
think it is exciting. And I think all of us will discover that
excitement together. O


TABLE 1
Three Kinds of Products
Different strategies are appropriate for different kinds of products.


Key Cost Speed Function
Basis Unit Ops Discovery f (Properties)
Action Sustain Chemistry Key Unified Theory


Spring 2006


Where the Jobs Are




Lh 1


2003


1975


Nanostructures


ICommodities IMolecules











The Next Millennium in ChE






CRYSTAL ENGINEERING:

From Molecules To Products


Preamble According to many contemporary scientists, engineers, policy-makers, and
business leaders, the future belongs to biotechnology, nanotechnology, and information technol-
ogy. Chemical engineering research and teaching are being changed by these fields, as dis-
cussed in this series of articles and elsewhere. Change is happening at a measured pace, and
biology has joined chemistry, physics, and mathematics as a fourth foundation discipline of the
chemical engineering curriculum. I have little to offer that has not already been said about bio,
nano, and info. However, there are other subjects that are of vital interest to society that are
squarely in the domain of chemical engineering and that have received less attention than their
worth. Among these, energy and crystalline solids rank high. I would like to say something
about both these topics, but I will confine myself to crystalline solids-particularly organic
materials. My goal is to highlight the importance of the solid state and to show how easily it can
be incorporated into the chemical engineering curriculum.




MICHAEL F. DOHERTY
University of California Santa Barbara, CA 93106-5080


Crystalline organic solids are ubiquitous as either fi-
nal products or as intermediates in the specialty
chemical, pharmaceutical, and home and personal-
care industries. Virtually all small molecular-weight drugs
are isolated as crystalline materials,"' and more than 90% of
all pharmaceutical products are formulated in particulate, gen-
erally crystalline, form.[21 Crystalline chemical intermediates,
such as adipic acid, are produced in large amounts to make
polymers and specialty products. Skin creams and other per-
sonal-care product formulations contain crystalline solids. In
most cases the properties of the crystalline solid have a ma-
jor impact on the functionality of the product as well as the
design and operation of the manufacturing process.
Crystal size (or size distribution), shape, enantiomorph, and
polymorph all influence product functionality. For example,
even a 50 micron particle in a hand cream makes the cream
feel gritty.'3' Size distribution is important in the manufacture
of beta-carotene, which is virtually insoluble in water and
only sparingly soluble in vegetable oils, and is used as a food
colorant. The color shade given to the food is determined by
the narrow size distribution, which must be in the submicron
range.'31 Crystal shape and polymorph influence solubility,
dissolution rate (which influences bioavailability), compress-


ibility (important for tabletting), and stability. The crystal
enantiomorph is of vital importance in the manufacture of
chiral materials, which has become a $150 billion industry in
recent years. The choice of solvent, along with the design
and operation of the manufacturing process, determines the
crystal properties. Moreover, crystal size, distribution, and
shape have a major impact on the design of the manufactur-
ing process since small crystals are difficult to separate from
solution, and needle-like crystals or plate-like crystals can be
difficult to filter and dry.

Michael F Doherty is a professor of chemical engineering at the Univer-
sity of California, Santa Barbara. He received his B.Sc. in chemical engi-
neering from Imperial College, University of London, in 1973, and his Ph.D.
in chemical engineering from Trinity College, University of Cambridge, in
1977 His research interests are in process design together with the asso-
ciated chemical sciences necessary to support the design activity. He has
published extensively on design and synthesis of nonideal separation sys-
tems, especially the coupling of separation with simultaneous chemical
reaction, and crystallization of organic materials from solution. He is the
holder of four patents, has published more than 150 technical papers and
one textbook, and has delivered more than 180 invited lectures. He has
served as a consultant for many multinational companies in the area of
process design and separations technology, and has served on the Cor-
porate Technical Advisory Boards for The Dow Chemical Company and
Rhone-Poulenc.


Copyright ChE Division of ASEE 2006
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The Next Millennium in ChE


Many important compounds exhibit polymorphism, i.e., the
existence of more than one crystal structure. Different poly-
morphs can have very different physical properties, includ-
ing color, hardness, and stability. Therefore, control of which
polymorph crystallizes in an industrial system is of vital im-
portance. For example, since bioavailability can vary greatly
among polymorphs of the same drug,"1 the U.S. Food and
Drug Administration requires the registration of each drug
polymorph and the strict production of only that form. It can
be difficult to control which polymorph crystallizes, even to
the extent that production output can change unexpectedly
from one form to another. This can be catastrophic, e.g., halt-
ing production until the process can be altered to produce the
original polymorph.151 Many in industry, particularly the phar-
maceutical industry, are now undertaking exhaustive poly-
morph screening to identify all possible/likely polymorphs
before beginning to scale up crystallization processes.[6'
The importance of crystal shape to processing and product
quality/functionality has been discussed in the context of
ibuprofen.'71 The primary interest in this system is the exist-
ence of high-aspect ratio needles when grown from nonpolar
hydrocarbon solvents such as hexane or heptane. Equant (i.e.,
low aspect ratio crystals with roughly equal sides) are formed
when grown from polar solvents such as methanol or etha-
nol. This was discovered by researchers at the Upjohn Com-
pany,'71 who patented the change in solvent as a process im-
provement.
The structure of this article is as follows. It begins by high-
lighting some of the advances made in the fundamentals of
crystallization during the last decade, together with recom-
mendations for where these topics can be inserted into the
curriculum. Next is a brief review of recent improvements in
CFD and population balance modeling for crystallizers. Third
are descriptions of new methods for process synthesis of flow-
sheets containing crystallization steps. Last are some recom-
mendations for incorporating crystal engineering into the core
of chemical engineering education and research.

FUNDAMENTALS OF CRYSTAL ENGINEERING
Crystal Structure
A crystal is an ordered three-dimensional array of mol-
ecules, and represents one of nature's most remarkable ex-
amples of self-assembly. This definition contains the con-
cept of periodicity. A solid material that has disordered struc-
ture, or that displays no long-range order (although it may
possess short-range order) is called amorphous.
All crystals have translational symmetry, i.e., repetition of
motifs by translational displacement in space. Each crystal
can be decomposed into a collection of unit cells, which are
the smallest structural units that re-create the entire three-
Spring 2006


A crystal is an ordered

three-dimensional array of

molecules, and represents one of

nature's most remarkable

examples of self-assembly.



dimensional crystal structure when they are repeated in space
by simple translation in every direction. Unit cells are paral-
lelepipeds, the vertices of which constitute a grid of points
called a lattice with its own periodicity and symmetry. The
unit cell also defines three sets of planes in space, each set
being parallel and equally spaced-the distance between the
planes in each set is called the interplanar spacing, which is
an important concept in crystal growth models. Within the
cell, symmetry operations relate the molecules that consti-
tute the contents of the cell. An asymmetric unit is the small-
est structural unit (e.g., a nonsymmetrical dimer, a single mol-
ecule, or part of a molecule) within which no symmetry ele-
ments operate. The collection of symmetry elements belong-
ing to a crystal structure is called a space group. Therefore, a
space group is the set of geometrical symmetry operations
that brings a three-dimensional periodic crystal into itself.
There are a total of 230 unique space groups. The number of
symmetry elements in a space group must be equal to the
number of asymmetric units in the cell.
It is important to realize that unit cells do not physically
exist in a lattice and the lattice does not physically exist in
the solid. These are mental constructs to help visualize the
solid structure. There are several different lattice arrangements
and unit cells that can be constructed-but only 14 possible
lattices that fill three-dimensional space. These lattices can
be further divided into seven crystal systems; each has a fixed
relationship between the cell's spatial dimensions and angles.
The seven systems are: cubic, tetragonal, orthorhombic, hex-
agonal, trigonal, monoclinic, and triclinic. Most organic mol-
ecules have uneven molecular shape that leads to low-sym-
metry crystal systems. The crystallographic systems with
uneven unit-cell parameters are the monoclinic, triclinic, and
orthorhombic. The majority of organic structures reported (ap-
proximately 95%) belong to these systems.
Molecules arrange themselves in crystals in such a way
that the whole spatial arrangement must belong to one of the
14 Bravais lattices. The total number of independent ways in
which molecules can decorate these lattices is 230 (corre-
sponding to the total number of independent space groups).











The Next Millennium in ChE


Fortunately, only a few of these space groups are important
in solid state chemistry. A more in-depth view of crystallog-
raphy is available from many sources, including Cullity,'81
Stout and Jensen,'9' and the International Tables for X-Ray
Crystallography.
Crystal structure and x-ray crystallography are well suited
for inclusion in the undergraduate physical chemistry se-
quence. Gavezzottil'Il has created an excellent visual intro-
duction to crystal symmetry, written in a tutorial style suit-
able for undergraduates.
Nucleation
Crystals are born by nucleation, which may be defined as
the formation of molecular solute clusters in solution that are
in dynamic contact with the solute molecules dissolved in
the solution. When the clusters reach a critical viable size
they become a crystalline particle that grows by the addition
of solute material on the crystal faces. Faces may appear or
disappear during growth depending on the relative growth
velocities of adjacent faces.
Nucleation can be divided into two types: primary and sec-
ondary. Primary nucleation is the formation of nuclei in solu-
tion whether or not suspended crystals are present. It is fur-
ther subdivided into homogeneous and heterogeneous. Ho-
mogeneous nucleation is the formation of nuclei in previ-
ously crystal-free solution. Primary heterogeneous nucleation
requires the preexistence of foreign bodies or catalytic sur-
faces in the solution. Foreign bodies can be dust particles,
nuclei of substances different from the solute, etc. Catalytic
surfaces may be roughness on the vessel walls, or a surface
that was designed specifically for this purpose, such as a com-
pressed surfactant monolayer (Langmuir) film or a self-as-
sembled monolayer. Secondary nucleation is used to describe
any nucleation mechanism that requires the presence of sus-
pended solute crystals. Secondary nucleation may take place
by several mechanisms: seeding, breakage, attrition due to
collision (collision nucleation), or removal of surface layers
through surface shear. Collision nucleation is the dominant
mechanism of secondary nucleation, whereby growing crys-
tals collide with the container walls, with a stirrer, or with
other crystals.
Homogeneous nucleation from clear solution is of special
interest because it is an important pathway in which the crys-
tal polymorph (crystalline packing structure) is created-see
the section below on Solution Mediated Polymorphism. The
classical view of this process is that it occurs from the solute
species clustering together in solution and then adopting the
ordered arrangement of the crystalline state to minimize the
free energy. The Gibbs-Thomson theory for the critical clus-
ter size, re, is also based on free energy minimization. Clus-
ters larger than r must grow in order to reduce the free en-
118


ergy of the total system solutee cluster + solution) while clus-
ters smaller than the critical size dissolve in order to reduce
the free energy of the system.
In the Gibbs-Thomson theory, it is assumed that only sol-
ute transfers to the nucleus from a supersaturated solution
(the composition of which is located in the metastable region
of the phase diagram). It is also supposed that the mass of the
nucleus phase is so small that the composition of the solution
phase is constant during the nucleation event. The total free
energy change, AG, consists of three terms: a change in bulk
free energy of the solution, a change of bulk free energy of
the nucleus, and a change of surface free energy of the nucleus.
The resulting expression for a spherical nucleus is

AG=-4-nr3 Aslute +47r2y (7)
3 vsolute

where lsolute is the difference in chemical potential of the
solute in the supersaturated solution and in the nucleus (this
term is always positive); vsolute is the molar volume of pure
solute in the nucleus phase. The chemical potential differ-
ence can be written

Absolute= RT In(l+o) (2)
where a represents the relative supersaturation (Csu"Pe"t-Csa')/Cs'.
The major assumption in Eq. (2) is that the activity coeffi-
cient of the supersaturated solution is equal to that in the satu-
rated solution-a reasonable approximation in most cases.
The leading term in Eq. (1) is always negative and represents
the decrease in bulk free energy due to phase change. The
second term in this equation contains the quantity y, which
is the surface free energy per unit area of nucleus (always a
positive quantity) and represents the increase in free energy
due to surface formation. The sum of these two terms pro-
duces a free energy plot with a single maximum that defines
the size of a critical nucleus, as shown in Figure 1 for the
alpha polymorph of the simplest amino acid, glycine, nucle-
ated from aqueous solution at room temperature.
The critical nucleus size is given by

rc= (3)
Ap solute
This theory predicts that typical values for a characteristic
length (diameter) of a critical nucleus are in the size range of
hundreds of nanometers. For a-glycine, the critical diam-
eter is approximately 600 nm. Recent computer simulations
on small molecules predict critical nucleus sizes of 3-6 nm.
The reason for the large discrepancy is currently unknown.
Using atomic-force microscopy in situ during the crystalli-
zation of the protein apoferritin from its aqueous solution,
Yau and Vekilov'" "12 have directly measured the crystalline
Chemical Engineering Education











The Next Millennium in ChE


packing structure and critical nucleus size of this material.
They found critical nucleus sizes in the range of a few tens of
nanometers (depending on the level of supersaturation). A
typical value is 40 nm for the cluster shown in Figure 2-
two orders of magnitude smaller than expected from tradi-
tional nucleation theory for large molecules. The molecular
arrangement within the nuclei were observed to be similar to
that in the bulk crystal, indicating that the crystal polymorph
is already established at these small length scales. Moreover,
the authors state, "Contrary to the general belief, the observed
nuclei are not compact molecular clusters, but are planar ar-
rays of several rods of 4-7 molecules set in one or two mono-

3D Nucleation of c-glycine
SAG (kJ) -
4*10


2"10

Sr(nm)
100 200 300 400 500

-2 10 '


Figure 1. Change in free energy as a function of nucleus
size for a -glycine grown from aqueous solution at room
temperature, where Vglycine= 46.71 cm3/mol, y= 148.1
erg/cm2, o = 0.02, and RT = 2.5 kJ/mol.


Figure 2. A flat, near-critical-sized cluster consisting of
approximately 20 apoferritin molecules.t121

Spring 2006


molecular layers. Similarly unexpected nuclei structures might
be common, especially for anisotropic molecules. Hence, the
nucleus structure should be considered as a variable by ad-
vanced theoretical treatments."
Using small-angle neutron scattering, Lefebvre, et al.,"3'
determined the critical length scales in phase separating poly-
mer blends of polymethylbutylene-polyethylbutylene. They
obtained results similar to those reported for proteins, namely,
critical diameters in the range of 20-50 nm.
Therefore, the current status of classical nucleation theory
is that it predicts critical nucleus sizes that are about two or-
ders of magnitude too high compared to the most recent mea-
surements by Balsara's group at UC Berkeley and Vekilov's
group at the University of Houston. Moreover, classical theory
does not provide the molecular arrangement within the
nucleus-this is an "input to" rather than an "output from"
the theory. There are opportunities here for major improve-
ments in nucleation theory that could have significant impact
on crystal engineering.
Nucleation is an excellent topic to include in the under-
graduate Solution Thermodynamics course. I like to teach
the two-dimensional theory in which the solid nucleus is taken
to be a rectangular lozenge of fixed thickness with variable
length and width (the number of dimensions in the theory is
equal to the number of independent lengths that are needed
to characterize the shape and size of the nucleus). This model
is much richer than the traditional one-dimensional spherical
nucleus described above, which is characterized by only one
spatial variable: diameter. In the two-dimensional nucleation
theory, the critical nucleus corresponds to a saddle-point in
the Gibbs free energy surface, which is easy to calculate and
visualize for undergraduates. Therefore, the expected nucle-
ation path corresponds to a trajectory through the free energy
landscape over a saddle-point barrier. This provides a nice
analogy to transition state theory and the reaction coordinate
over a saddle-point barrier in chemical reaction rate theory.
Moreover, it is easy to show that the shape of the critical
two-dimensional nucleus satisfies the Wulff construction for
a two-dimensional equilibrium shape. That is, the two-dimen-
sional critical nucleus attains a shape that minimizes its total
surface energy for the given (faceted) volume. Teaching this
material to undergraduates also provides a good vehicle for
explaining the difference between surface energy' and sur-
face stress." In the case of liquids, all processes of interest

SThe reversible work per unit area needed to create a siuface-if the
variation in surface area does not change the siuface density of
molecules, then the specific surface work is smiface energy.
The reversible work per unit area needed to elastically stretch a
preexisting stuface-if the variation in simface area changes the
stuface density of molecules, then the specific surface work is sur-
face stress.











The Next Millennium in ChE


involve variations in area without varying the surface den-
sity, and the surface work represents a surface-free energy.
The traditional processes involving surface energy are creat-
ing a soap bubble and cleaving a solid into two parts, while
the traditional example of a process involving surface stress
is blowing up a rubber balloon. Both types of energy are ex-
pected to play a part in creating a solid nucleus, yet there is
no theory that accounts for this. Finally, a good reason for
teaching this material to undergraduates is to show them that
not all is known, even in traditional areas of science that have
been studied for a long time.
Growth Models
Evidence suggests that crystal faces grow by one of three
mechanisms: a screw dislocation mechanism, a two-dimen-
sional nucleation mechanism, or by rough growth. It is also
known that different faces of a crystal may grow by different
mechanisms, according to the solute-solvent interactions at
the interface (surface-free energy) and the level of supersatu-
ration. At low supersaturation levels, or large surface-free en-
ergies, the screw dislocation mechanism is normally opera-
tive. The original theory, developed by Burton, Cabrera, and
Frank,"14' proposed that screw dislocations, which exist on
real crystal faces at all supersaturation levels, provide an in-
finite source of steps onto which oncoming particles can be
incorporated. According to this theory, growth occurs by the
flow of steps across the surface, which forms a spiral. Spirals
have been observed on many faces of many crystals"5"17 (see
Figure 3). At moderate levels of supersaturation, the two-
dimensional nucleation mechanism may apply. Above a criti-
cal level of supersaturation, the face is roughened and growth
proceeds at a high rate.
The BCF expression for the rate of growth normal to a sur-
face is:

Rhkl V hklhhkl (4)
RhkI ----- (4)
Yhkl
where vhkl is the lateral step velocity, hhkl is the step height,
which can be approximated by d. (the interplanar spacing)
for monolayer height, and yhk1 is the distance between steps.
Since growth occurs at kink sites (vacancies in steps where
solute growth units can incorporate-see Figure 1 in Chen
and Vekilov1I 8 for a beautiful image of kink sites on a step of
crystallized ferritin), the lateral step velocity depends mainly
on the density of kink sites. In the simplest case, molecules
along the edges of a spiral are found in one of three
microstates: a positive kink site, a negative kink site, and no
kink site. The energy for each of these microstates can be
calculated, and if we assume that they occur in their most
probable configuration, then the probability of finding a kink
site along an edge is given by the Boltzman distribution. This


Figure 3. Four consecutive images of a spiral growing
from a screw dislocation on a calcite crystal face.t17


Figure 4. Reported and predicted morphologies for
a -glycine crystallized from aqueous solution.
(a) Experimentally grown crystal from Boek, et al.1271
(b) Predicted shape using the form of the BCF model in
Eq. (4) with a dimer growth unit. (c) Shape predicted by
Eq. (4) using a modified monomer growth unit.1261


Chemical Engineering Education


(120) ii

(110


4020)
(c)











The Next Millennium in ChE
^__________ _________________________


result provides a nice link between elementary statistical
mechanics and the kinetics of crystal growth. (In my experi-
ence, if you want to teach undergraduates the methods of sta-
tistical mechanics so that they understand, use the textbook
by Kittel and Kroemer."91)
Crystal Shape
It is well known that crystals grow in a variety of shapes in
response to both internal and external factors. Some of these
factors can be manipulated (e.g., solvent type, solution tem-
perature, and supersaturation) by crystal engineers to steer
crystals toward a target shape or away from undesired shapes.
Experiments performed on the growth of crystals from
spherical seeds have shown that flat faces appear during
growth. Some of the faces that appear eventually disappear,
while others grow in size, eventually leading to a fully facet-
ted stationary (steady state) shape. The shape of crystals at
thermodynamic equilibrium can be determined using Gibbs'
approach of minimality of the total surface-free energy per
unit volume. This thermodynamic equilibrium condition leads
to the Wulff construction to determine crystal shape

Yi
--constant, i= 1,...,N (5)
hi

where yi is the specific surface-free energy of face i, hi is the
perpendicular distance between the origin and face i, and N is
the number of faces. Only very small particles (nanoparticles)
can undergo rapid shape change to reach equilibrium, during
which the size change is not substantial. For larger particles,
however, the number of elementary transport processes that
have to occur to achieve significant changes in shape is so
large compared with the lowering of the surface-free energy
that the rate of equilibration becomes negligible.1201 For crys-
tals grown from seeds, steady state shapes (that have self-
similar growth) are therefore observed more often than the
equilibrium shapes. Wulff's condition was modified by
Chernov 11 (also see Cahn, et al., '22) to determine the crystal
shape at steady state, given as:


constant, i=l,...,N


where R, is the perpendicular growth velocity of face i. As
noted in the previous subsection, many mechanisms and mod-
els are available to estimate the perpendicular growth veloci-
ties of facets, but in most solution crystallizations only one
model-the screw dislocation model [BCF model, Eq. (4)]-
has the proven capability to correctly estimate the relative
growth rates of crystals grown from solution. A comprehen-
sive validation of this modeling approach is given by Liu, et


al.,'213 Winn and Doherty,r24'25' and Bisker-Leib and Doherty.[26]
The shapes of many organic crystals have been successfully
predicted with this approach, e.g., urea grown from aqueous
solution, ibuprofen grown from methanol and from hexane,
adipic acid grown from water. Figure 4 compares the experi-
mental and predicted steady state growth shapes of a glycine
crystallized from aqueous solution. This is a particularly sen-
sitive test of the approach due to the complex network of
hydrogen bonds that are formed in the solid state. Although
there are many aspects of this modeling approach that need
improvement, such as a priori identification of the nature of
the growth units that incorporate into the growing crystal
faces, the approach is already sufficiently well developed
for immediate application to engineering design.
Although significant progress has been made recently on
predicting the steady state shapes of organic materials crys-
tallized from solution, there is less to report on the important
related matter of predicting shape evolution from an initial
seed or nucleus shape through to the final steady state shape.
The only evolution models reported in the literature are for
two-dimensional crystals, which apply to materials that crys-
tallize in flat plate-like shapes, such as succinic acid grown
from water (flat hexagonal crystals), and L-ascorbic acid (vi-
tamin C) grown from water (flat rectangular crystals). The
dynamics of shape evolution for three-dimensional crys-
tals are quite complicated as faces, edges, and vertices
appear or disappear during growth. The definitive study
is yet to be done.
Although some may disagree with me, I think the topic of
crystal growth and crystal shape as outlined above is good
material for inclusion in an undergraduate transport course.
Solution Mediated Polymorphism
The phenomenon of polymorphism-a solid crystalline
phase of a given compound resulting from the possibility of
at least two crystalline arrangements and/or conformations
of the molecules of that compound in the solid state-has
been known to exist for over two centuries.[J28 Despite this,
its prevalence presents one of the greatest obstacles to the
solids-processing industry today. To obtain the desired prop-
erties of the product, the correct polymorph must be obtained
since they have different physical properties: melting points,
solubilities, bioavailabilities, enthalpies, color, and many
more. Differences between polymorphs are crucial for indus-
tries such as the pharmaceutical industry, where differences
in dissolution rates between two polymorphs may mean that
one polymorph is a potential product because of its high dis-
solution rate (high efficacy) while another is not due to its
negligible dissolution. A dramatic example of this phenom-
enon is provided by the Ritonavir polymorphs.[51


Spring 2006











The Next Millennium in ChE


Paracetamol (acetaminophen) is an analgesic drug that is
used worldwide as a pain reliever. Due to its commercial
importance, acetaminophen has been subject to many crys-
tallization experiments and, in particular, polymorph studies.
Paracetamol has three known polymorphs. Monoclinic
paracetamol is the thermodynamically stable form at room
temperature and, therefore, it is the commercially used form.
Unfortunately, it is not suitable for direct compression into
tablets, since it lacks slip planes in its structure, which are
necessary for the plastic deformation that occurs during com-
paction. Consequently, it has to be mixed with binding agents,
which is costly in both time and material. Crystallization of
the orthorhombic polymorph (form II) of paracetamol from
solution is more desirable since it undergoes plastic defor-
mation and is therefore suitable for direct compression. In
addition, it is believed to be slightly more soluble than form
I. Until 1998 there was no reproducible experimental proce-
dure available for the crystallization of form II from solu-
tion. The only method that
had been reported for bulk
preparation of form II was to
grow it as polycrystalline
material from fused form I.
In 1998, Gary Nichols
from Pfizer and Christopher
Frampton from RocheE291 de-
scribed a laboratory-scale
process to crystallize form II
from solution. They found
that the orthorhombic poly-
morph of paracetamol could
be crystallized from super-
saturated solution of indus-
trial methylated spirits (etha-
nol with approximately 4%
methanol) by nucleation
with seeds of form II, main-
taining crystallization at a
low temperature of 0 oC and polymorphs
Figure 5. Two polymorphs
collecting the crystals within solution: alpha-glycine (sh
one hour after nucleation glycine (n
began. The typical yield
achieved was less than 30%,
but they proposed that when the process was optimized, a
commercial application was possible. By having better con-
trol over the crystallization process, they managed to crystal-
lize only the orthorhombic polymorph and to have the de-
sired crystal shape.
Ostwald noted in his Rule of Stages describing phase tran-
sitions that it is not the most thermodynamically stable state
that will normally appear first but that which is the closest, in
122


ofgl
aped
eedl


free energy, to the current state.1 3""3 In accordance with this
rule, crystallization of a compound having two polymorphs
will often proceed first with the growth of the metastable form
until the solution composition achieves the equilibrium solu-
bility of this form. When the saturation concentration of the
metastable form is reached it will stop growing. The stable
form may have nucleated at any point, determined by rela-
tive kinetics, up to and including when the saturation of the
metastable form is reached. The stable form will then grow,
thus causing the solution to be undersaturated with respect to
the metastable form, causing it to begin to dissolve. Once the
metastable form has completely dissolved at the expense of
the growing stable form, the stable form will grow until the
solution reaches its equilibrium solubility with respect to the
stable form.3'21 For example, a snapshot of the polymorphic
transformation of glycine crystallized from a water/ethanol
mixture is shown in Figure 5. At the beginning of the crystal-
lization, beta-glycine (needle) crystals form first. This is the
less stable polymorph. After 10
minutes, the more stable poly-
morph, alpha-glycine (shaped as
a coffin), grows at the expense
of the beta-glycine, which dis-
solves.
A more complete understanding
of solution-mediated polymor-
phism will involve appropriate
integration of nucleation, growth,
and dissolution, with the thermo-
dynamic equilibrium phase dia-
gram for the polymorphs.13i]

Crystallizer Design
Crystallization processes are
designed to achieve specific ma-
terial properties in the final solid
product, which are normally de-
termined by the crystal purity,
ycine in water-ethanol polymorph, mean particle size,
as a coffin) and beta- size distribution, and crystal
es). 1'3 habit. The design decisions that
influence these material charac-
teristics include: choice of sol-
vent, tailor-made surface-active modifiers,'1-71 fines removal
system, and the temperature and supersaturation fields in-
side the crystallizer (which are determined by the solute feed
concentration and temperature, crystallizer temperature, ves-
sel volume and geometry, agitation rate, and/or antisolvent
feed rate or evaporation rate, as appropriate). Buildup of im-
purities in the recycle streams also has the potential to sig-
nificantly influence crystalline material properties.
Chemical Engineering Education










The Next Millennium in ChE


Considering the fundamentals of crystallization, it is tempt-
ing to envision crystals growing quietly in a uniform me-
dium. This is an ideal seldom if ever realized in industrial
crystallization. In most industrial crystallization processes,
crystals grow suspended with myriad similar crystals in large,
vigorously agitated vessels. Frequently, the solution compo-
sition in the vessel is nonuniform both temporally and spa-
tially. Growing crystals are subject to collisions with other
crystals, the vessel agitator, wall, and internals. These phe-
nomena have a significant, sometimes profound, effect on
the properties of the resulting crystals. Crystallizer and crys-
tallization process design attempt to reconcile and man-
age these competing effects to produce adequate, even
superior crystals.
Modeling crystallizer flows is critically important and pre-
sents many difficulties, such as concentrated two-phase flows,
turbulent flow, complicated geometries, and a particle phase
that is changing in concentration and properties over time.
Despite these challenges, advances in closure modeling, nu-
merical solution techniques, and computational power are
beginning to make computational fluid dynamics (CFD) a
useful tool for characterizing crystallizer flows. Advances
have also been made incorporating the effect of the suspended
particles on the flow field.
Currently, there is great hope for Lattice Boltzmann tech-
niques to simplify the computational treatment of the equa-
tions of motion, making numerical solution much more effi-
cient. The techniques are also amenable to including the ef-
fect of solidsi'38 and are becoming commonly used. Because
they are so much more efficient than traditional solution tech-
niques, significantly more complicated and consequently
more realistic problems can now be solved. It remains a chal-
lenge to incorporate changing particle size distribution (PSD)
into these models, but this is an area of current research and
progress is being made.'39
The ultimate goal is to combine transport and population
balance modeling. Only then will realistic PSD predictions
be possible for a wide variety of nonideal systems. Progress
has been made, but a model applicable to a wide variety of
conditions remains elusive.

SYSTEMS DESIGN / PROCESS SYNTHESIS
Normally, large amounts of dissolved solute remain in so-
lution in the effluent stream of a continuous crystallizer, or at
the end of a batch crystallization. In either case, the crystals
are separated from the solution, and the liquor is recycled.
The crystallizer, therefore, is part of a larger flowsheet, which
may involve reactors, dissolvers, additional crystallizations,
various kinds of separators, heaters and coolers, etc. Both the
structure of the flowsheet and the devices and their operating
Spring 2006


Considering the fundamentals of

crystallization, it is tempting to

envision crystals growing quietly in

a uniform medium. This is an ideal

seldom if ever realized

in industrial crystallization.



policies influence the recycle flow rate and composition,
which in turn influence the performance of the crystallizer.
Surface active impurities and their buildup in recycle loops
can have a major impact (often adverse) on crystallizer
performance.
In recent years geometric methods have proven to be use-
ful for the systematic generation of process flowsheets. One
such tool, the crystallization path map, is useful for finding
feasible flowsheets in which crystallization steps occur. These
maps are closely related to residue curve maps for the syn-
thesis of azeotropic distillation systems.'40' The crystalliza-
tion paths are trajectories of the liquid composition in a crystal-
lizer as the solid is formed and removed from solution.!4 421
The presence of eutectics and compounds causes the pres-
ence of crystallization boundaries, which divide the map into
distinct crystallization regions. These regions are
nonoverlapping and mutually exclusive; that is, a liquid tra-
jectory that starts in one region cannot cross a boundary (ex-
cept by noncrystallization means) into an adjacent region.
Within each region there is one and only one crystal product,
which may be a pure component, a eutectic, or a compound.
Crystallization maps are useful for synthesizing flowsheets
for adductive crystallization (where a compound is the de-
sired crystal product), extractive crystallization, and many
other embodiments.'43-41 Although these maps are valuable
for laying out process flowsheets, the accumulation of impu-
rities associated with process recycle and the effect on crys-
tal properties both remain difficult to predict. Therefore, in-
tegrated pilot-scale testing including all recycle streams is
still required for confident system design, but there are sig-
nificant modeling opportunities here that will enable more
reliable and rapid development of process flowsheets.

SUMMARY AND CONCLUSIONS
During the last decade there have been significant advances
made in every aspect of crystal engineering. New experimen-
tal techniques, such as atomic force microscopy, allow us to
123












The Next Millennium in ChE


explore crystal surfaces and embryonic nuclei to learn about
their formation and growth, infrared and Raman spectros-
copy allow us to follow supersaturation changes and poly-
morphic transformations in situ while crystallization is tak-
ing place. New models have been developed to predict the
influence of both internal and external factors on crystal poly-
morph and shape. Molecular templates are being developed
to control crystal form and structure. Advances in fluid me-
chanics and transport phenomena have added greatly to our
understanding of mixing patterns and particle trajectories in-
side crystallizer vessels of realistic geometry. These and other
advances not mentioned or not yet even anticipated, are ex-
pected to continue.
Most of these advances are not being made by chemical
engineers, however. And moreover, they are taking place in
isolation. There is a large disconnect, for example, between
the microscopic models for growth of individual crystal faces
and the macroscopic models for CFD and PSD prediction.
Perhaps the larger question is, "How do we incorporate our
rapidly advancing knowledge and modeling capability to
make better products?"
There are major opportunities here for chemical engineers
who must be encouraged to take up the challenge. Specific
recommendations for incorporating crystal engineering into
chemical engineering research and undergraduate education
include:
Education
(1) Crystalline solids should be one of the core themes
throughout the chemical engineering curriculum.
Topics include: Thermodynamics course- thermody-
namics of solid-liquid phase diagrams and solubility
curves, spinodal curve and metastable zone curve,
traditional nucleation theory. Transport course-
diffusion of solute through a solution to a growing
crystal surface, estimates of characteristic times for
bulk diffusion, surface diffusion and integration of
solute at kink sites on a crystal surface, models for
flow of steps across crystal surfaces. Reaction
Engineering course- simultaneous reaction and
crystallization (i.e., precipitation). Separation course-
design of batch and continuous crystallizers. Design
course- simultaneous product and process design for
crystalline products (e.g., a dye, a pigment, or a
simple pharmaceutical such as paracetamol-trade
name Tylenol).

(2) Solid state chemistry should be part of the under-
graduate chemistry sequence. Topics include: crystal
structure and crystallography, nucleation (both
traditional and statistical mechanics models), solid
state bonding and bond chains, and surface growth
models-especially the spiral dislocation model.


There are numerous useful monographs and textbooks avail-
able on the subject of crystallization that may be used for
teaching undergraduates. These include: Randolph and
Larson,t461 Mullin,1471 and Davey and Garside.14s' The last of
these is short, inexpensive, and extremely well written. Un-
dergraduates should be happy to purchase this book.
Research Topics

(3) New models and experiments for understanding,
directing, and controlling nucleation and polymorph
selection
(4) Models for understanding and predicting polymorphic
phase transitions-both solution mediated and solid
state transformations
(5) Models and experiments for predicting the effect of
additives and impurities on crystal properties (e.g.,
crystal shape, size, polymorph)
(6) Improved models for CFD of dense suspensions of
crystals that are growing inside a solution crystallizer
(7) Improved procedures for simultaneous product and
process design for crystalline particulate products;
application and testing of the procedures in such
product sectors as: chiral and pharmaceutical
products, home and personal care (e.g., skin creams,
suntan lotions), food (e.g., margarine, chocolate, ice
cream), dyes and pigments, bulk chemicals (e.g.,
adipic acid), and specialty chemicals

ACKNOWLEDGMENT
I would like to acknowledge helpful discussions with Dr.
Daniel Green of the DuPont Company who influenced my
thinking about this subject, particularly in the area of CFD
modeling.

REFERENCES
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to Drug Substance and Drug Product Development," Foundations of
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"Dealing with the Impact of Ritonavir Polymorphs on the Late Stages
of Bulk Drug Process Development," Org. Process Res. Dev., 4 413-
417(2000)
6. Desikan, S., S.R. Anderson, P.A. Meenan, and P.H. Toma, "Crystalli-
zation Challenges in Drug Development: Scale-up for Laboratory to


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The Next Millennium in ChE


Pilot Plant and Beyond," Current Opinion in Drug Disc. & Develop-
ment, 3 6. 723 (2000)
7. Gordon, R.E., and S.I. Amin, "Crystallization of Ibuprofen," U.S.
Patent Number 4, 4 76, 248 (1984)
8. Cullity, B.D., Elements ofX-Ray Diffraction. 2nd Ed., Addison-Wesley.
Reading. MA (1978)
9. Stout. G.H.. and L.H. Jensen. X-Ray Structure Determination. John
Wiley, New York (1989)
10. Gavezzotti, A. "Crystal Symmetry and Molecular Recognition." Chap-
ter 1 in Theoretical Aspects and Computer Modeling of the Molecular
Solid State, A. Gavezzotti, ed.. John Wiley, New York (1997)
11. Yau, S.-T., and P.G. Vekilov, "Quasi-Planar Nucleus Structure inApo-
ferritin Crystallization," Nature, 406 494 (2000)
12. Yau, S.-T., and P.G. Vekilov, "Direct Observation of Nucleus Struc-
ture and Nucleation Pathways in Apoferritin Crystallization." J. Am.
Chem. Soc., 123 1080 (2001)
13. Lefebvre, A.A.. J.H. Lee, N.P. Balsara, and C. Vaidyanathan, J. Chem.
Phys.. 117 9063 (2002)
14. Burton, W.K.. N. Cabrera, and FC. Frank. "The Growth of Crystals
and the Equilibrium Structure of Their Surfaces." Phil. Trans. Roy.
Soc., A243 299 (1951)
15. Geil, P., Polymer Single Crystals. Interscience (1963)
16. Land, T.A., A.J. Malkin, Y.G. Kutznesov. A. McPherson, and J.J. De
Yoreo. J. Crystal Growth, 166 893 (1996)
17. Paloczi, G.T., B.L. Smith, P.K. Hansma, D.A. Walters, and
M.A.Wendman, "Rapid Imaging of Calcite Crystal Growth Using
Atomic Force Microscopy with Small Cantilevers." Applied Physics
Letters. 73 1658 (1998)
18. Chen, K.. and P.G. Vekilov. "Evidence for the Surface-Diffusion
Mechanism of Solution Crystallization from Molecular-Level Obser-
vations with Ferritin," Phys. Rev. E. 66 021606 (2002)
19. Kittel, C., and H. Kroemer, Thermal Physics, W.H. Freeman. New
York (1980)
20. Herring. C.. "The Use of Classical Macroscopic Concepts in Surface
Energy Problems," in Structure and Properties of Solid Surfaces, R.
Gomer and C.S. Smith, eds., University of Chicago Press, Chicago
(1953)
21. Cherov, A.A., "The Kinetics of the Growth Forms of Crystals," Sov.
Phys. Cryst., 7728 (1963)
22. Cahn, J.W., J.E. Taylor, and C.A. Handwerker, "Evolving Crystal
Forms: Frank's Characteristics Revisited," Sir Charles Frank, OBE.
FRS, An Eightieth Birthday Tribute. R.G. Chambers, J.E. Enderby and
A. Keller, eds., Hilger, New York (1991)
23. Liu, X.Y., E.S. Boek, W.J. Briels, and P. Bennema, "Prediction of Crys-
tal Growth Morphology Based on Structural Analysis of the Solid-
Fluid Interface." Nature, 374 342 (1995)
24. Winn, D., and M.F. Doherty, "A New Technique for Predicting the
Shape of Solution-Grown Organic Crystals," AIChEJ. 44 2501 (1998)
25. Winn, D.. and M.F. Doherty, "Modeling Crystal Shapes of Organic
Materials Grown from Solution," AIChEJ. 46 1348 (2000)
26. Bisker-Leib, V., and M.F. Doherty, "Modeling Crystal Shape of Polar
Organic Materials: Applications to Amino Acids," Crystal Growth &
Design. 3 221 (2003)
27. Boek, E.S., D. Feil, W.L. Briels, and P.J. Bennema, Cryst. Growth,
114 389-410(1991)


28. Bernstein, J., Polymorphism in Molecular Crystals, Oxford Univer-
sity Press, Oxford, UK (2002)
29. Nichols. G., and C.S. Frampton, "Physicochemical Characterization
of the Orthorhombic Polymorph of Paracetamol Crystallized from So-
lution." J. Pharmaceutical Sciences, 87 684 (1998)
30. Ostwald. W.F., "Studien uber Die Bilding und Umwandlung fester
Korper (Studies on the Formation and Transformation of Solid mate-
rials)." Z. Phys. Chem.. 22 289 (1897)
31. Grant. D.J.W., "Theory and Origin of Polymorphism," in Polymor-
phism in Pharmaceutical Solids, H.G. Brittain, ed., Vol. 95 of Drugs
and the Pharmaceutical Sciences, Marcel Dekker, New York (1997)
32. Cardew, PT., and R.J. Davey, "The Kinetics of Solvent-Mediated Phase
Transformations," Proc. R. Soc., A398 415 (1985)
33. Ferrari, E.S., R.J. Davey, W.I. Cross, A.L. Gillon, and C.S. Towler,
"Crystallization in Polymorphic Systems. The Solution-Mediated
Transformation of Beta to Alpha Glycine," Crystal Growth and De-
sign. (3) 53 (2003)
34. Garcia, E., C. Hoff, and S. Veesler, "Dissolution and Phase Transition
of Pharmaceutical Compounds," J. Crystal Growth, 237-239, 2233
(2002)
35. Michaels, A.S., and A.R. Colville, "The Effect of Surface Active Agents
on Crystal Growth Rate and Crystal Habit," J. Phys. Chem., 64 13
(1960)
36. Klug, D., and J.H. Van Mil. "Adipic Acid Purification," U.S. Patent
Number 5,296, 639(1994)
37. Weissbuch, I., L. Addadi, L. Lahav, and L. Leiserowitz, "Molecular
Recognition at Crystal Interfaces," Science. 253 637 (1991)
38. Seta. T., K. Kono, and S. Chen, "Lattice Boltzmann Method for Two
Phase Flow," Int. J. Modern Phys. B. 17 169 (2003)
39. Brown, D.B.. S.G. Rubin, and P. Biswas. "Development and Demon-
stration of a Two/Three Dimensional Coupled Flow and Aerosol
Model," Proceedings of the 13th AIAA Applied Aerodynamics Confer-
ence, American Institute of Aeronautics and Astronautics (1995)
40. Doherty, M.F., and M.F. Malone, Conceptual Design of Distillation
Systems, McGraw-Hill, New York (2001)
41. Ricci, J.E., The Phase Rule and Heterogeneous Equilibrium, D. Van
Nostrand Co., New York (1951)
42. Slaughter, D.W.. and M.E Doherty, "Calculation of Solid-Liquid Equi-
librium and Crystallization Paths for Melt Crystallization Processes,"
Chem. Engng Sci., 50 1679 (1995)
43. Rajagopal, S., K.M. Ng, and J.M. Douglas, "Design and Economic
Trade-Offs of Extractive Crystallization Processes," AIChE Journal,
37437(1991)
44. Wibowo, C.. L. O'Young, and K.M. Ng, "Streamlining Crystalliza-
tion Process Design," CEP. 100, 1 30 (2004)
45. Lashanizadegan, A., D.T.M. Newsham, and N.S. Tavare, "Separation
of Chlorobenzoic Acids by Dissociation Extractive Crystallization,"
Chem. Engng Sci., 56 2335 (2001)
46. Randolph, A.D., and M.A. Larson, Theory of Particulate Processes,
Academic Press, San Diego (1988)
47. Mullin, J.W., Crystallization, Butterworth-Heinemann, Oxford, UK
(1993)
48. Davey, R.J., and J. Garside, From Molecules to Crystallizers, Oxford
University Press, Oxford, UK (2000) 1


Spring 2006











The Next Millennium in ChE


INSIDE THE CELL

A New Paradigm for Unit Operations

and Unit Processes?







JEROME S. SCHULTZ
University of California Riverside, California


Traditionally the chemical engineering paradigm for de-
signing industrial plants has been to separately con-
sider unit operations and unit processes. Although
these terms are not prevalent in current curricula, courses in
separations, reaction engineering, polymer engineering, etc.,
reflect this traditional view.
The usual scheme of process development starts at the labo-
ratory bench. And with experimentation and exploration, con-
ditions are optimized and then the process goes through a
scale-up procedure to reach commercial production needs.
Recent advances in MEMS technologies, however, have led
to the implementation of Lab-On-a-Chip devices such as the
integrated DNA analysis chip developed by Bums, et al.'"
(see Figure 1). These analytical devices bring together vari-
ous elements of unit processes such as separation steps, reac-
tion steps, and process control (detection and sensing proce-
dures). The capability for miniaturization and integration has
led some chemical engineers (e.g., Klavs Jensen) to envision
an entirely new paradigm for production methods, i.e., scaling
down instead of scaling up. Figure 2 from Professor Jensen's
Web site succinctly illustrates this contrast in paradigms.
Given the immense efforts in MEMS and nanotechnology
toward miniaturization and integration, one can readily specu-
late about potential future methods for carrying out chemical
processes through the application of these technologies. The


organizational structure of biological cells could have im-
portant lessons and impact in this regard. As the extensive
structural and operational characteristics of the biological cell
are being revealed, it is becoming clear that biological sys-
tems have evolved with a much more integrated design para-
digm of processes and operations than the traditional chemi-
cal engineering approach.


Jerome Schultz received his B.S. and M.S in chemical engineer-
ing from Columbia University, and his Ph.D. in biochemistry from
the University of Wisconsin in 1958. He started his career in the
pharmaceutical industry (Lederle Laboratories) then joined the
University of Michigan, where he was chairman of the Department
of Chemical Engineering. He spent two years at the National Sci-
ence Foundation as deputy director of the Engineering Centers
Program. In 1987 he joined the University of Pittsburgh as director
of the Center for Biotechnology and Bioengineering, and was the
founding chairman of the Department of Bioengineering-a nation-
ally ranked degree program in bioengineering. He recently spent a
year at NASA's Ames Research Center as a senior scientist in their
Fundamental Biology Program. In 2004 Dr. Schultz joined the fac-
ulty at the UC Riverside as the director of the newly formed Bioengi-
neering Program and the Center for Bioengineering.
He is a member of the National Academy of Engineering, a Fel-
low of the American Association for the Advancement of Sci-
ences, Editor of Biotechnology Progress, and was a founding
Fellow and President of the American Institute for Medical and
Biological Engineering.


Copyright ChE Division of ASEE 2006
Chemical Engineering Education











The Next Millennium in ChE


New advances in genomics, proteomics, metabolomics, cell
signaling, and control have allowed the documentation of the
thousands of species and interactions that comprise the inter-
nal milieu of cells. This vast amount of information has al-
lowed the harnessing of biological cells for many purposes
such as preparation of many biologics (e.g., insulin and EPO
[erythropoietin, monoclonal antibodies]), as well as the use


SAMPLE DROP MN THERMAL GEL GEL
LOADING METERNG MIXING REACTION LOADING ELECTROPHORESIS
L---i r "-i ,- R- -




S-- m-- ^< UID ENTRY D ET E I RUNNING BUFFER
5mm PORTS PHOTOOTECTORS PORTS

Figure 1. An example of a Lab-On-a-Chip device. This is
a DNA analysis system devised by Mark Burns and
associates.1'1 Various "unit operations" including meter-
ing, mixing, reactions, separations, and detection are
combined in a single device.


Microchemical Systems Scale Down and Out


Figure 2. Klavs Jensen's concept for a new paradigm
in chemical process development that utilizes the
multiplexing capabilities of MEMS technology to carry
out integrated synthesis and separation operations
in the same unit.


of cells for detoxification of herbicides.
Much of our thinking related to the future of biotechnol-
ogy is based on our appreciation of biological systems de-
duced from the dissection and separation of the components
of cells such as enzymes, signaling proteins, antibodies, RNA,
and DNA. Much of the richness of biological systems, how-
ever, resides in the structural features of cells. To date, many
of the structural elements that have been deduced from elec-
tron micrographs are categorized as organelles. Some of the
classes of organelles that have been identified include the
nucleus, mitochondria, lysosomes, peroxisomes, vesicles,
chloroplasts, and golgi (Figure 3). It is clear that cells are not
a bag of enzymes and substrates, i.e., a CSTR.
Although the morphology of these structural elements is
fairly well characterized by electron microscopic methods,
the functional and dynamic biological/chemical processes that
are taking place in these structures are not well understood at
all. Early hints from the study of some of these organelles
have revealed that biology does not separate unit processes
from unit operations, but rather integrates them. For example,
in chloroplasts the capture of photons and fixation of carbon
dioxide into carbohydrates simultaneously results in photoly-
sis-the separation of protons and oxygen evolution. Ribo-
somes integrate the genetic code and protein synthesis.
Most organelles are known to be complex multi-membra-
nous structures, but the composition and detailed organiza-
tion of these units are not known. One reason for the lack of
detailed understanding is that the typical dimensions of these
structures is on the order of nanometers and thus below the
resolution of optical microscopes. So they cannot be visual-
ized in detail while in a normal functional mode. This lack of


Figure 3. Diagramatic illustration of the various struc-
tures within a cell illustrating the complex structures
inside of cells that are responsible for much of the
biosynthetic activities of living systems.


Spring 2006


Not to scale







































Figure 4. Operational characteristics of near field microscopy (left). Close-up of the optical scanning probe (right). This is
one of the devices that will allow the visualization of structures within living cells and their behavior.


Ex=395 nm


Em=527 nm


+Glucose

-Glucose


GFPuv






(b)


Ex=395 nm


Em=527 nm


GFPuv


I YP Thr-Ser- GBP Gly-Thr-I GFP

Figure 5. Glucose-responsive protein engineered from a glucose
binding protein from E. coli, and two different green fluorescent
proteins. This type of structure can be introduced into a cell via a
plasmid to result in the biosynthesis of the sensor protein within
the cell. (a) In the absence of glucose the two fluorophores are in
close proximity and exhibit fluorescent energy transfer (FRET)
(left). In the presence of glucose the protein opens, and FRET is
reduced. (b) Structure of the fusion protein.110l


knowledge has hampered our ability to mimic these biologi-
cal systems for chemical processes.
Hope is on the way, however. To deal with this issue, indi-
rect methods are under active development to elucidate
mechanisms of the functioning of organelles.


Figure 6. Confocal image of a yeast cell containing
a maltose responsive protein similar to that
illustrated in Figure 5. The intensity of fluores-
cence is indicative of the concentration of maltose
in various regions of the cell. By incorporating
various indicator proteins of this type within cells,
one could monitor the dynamics of biosynthesis of
specific biomolecules in space and time. Vis a
vacule. (Bar = 1 micron). "'1


Many new instrumental techniques are being developed to
provide some real-time measurements of the behavior of sub-
cellular structures. These techniques include confocal micros-
copy,[2] two-photon microscopy,1 3 and optical coherence to-
mography.[41 Near field microscopy,151 Figure 4, allows the


Chemical Engineering Education


Incident light
X=500 nm


Light wavelength (X) 500 nm
Probe:
aperture size (a) 25-100 nm
evanescent field ain
tip-sample gap 5-50 inm
Sample:
feature size <
skin depth 0- co
Optics:
Far-field detector 1-100 mm
Interference effects )/4


The Next Millennium in ChE











( The Next Millennium in ChE

a) visualization of structural elements near the surface of the
I cell. Basically an optical fiber is drawn down to diameters
less than the wavelength of light and placed in contact with
the cell's outer membrane. The probe is scanned across the
(a) cell membrane to provide a map of structures just beneath
the membrane surface.
Several clever concepts based on various reporter tech-
niques have also been described recently that are beginning
to give specific dynamic data on intracellular events. The rap-
(b) idly expanding knowledge base on the structure and proper-
ties of green fluorescent proteins has opened up many oppor-
itunities for the protein engineering of intracellular probes. A
multitude of techniques is available for incorporating plas-
mids for these proteins into cells. These reporter indicators
(C) can be either freely mobile within the cell or localized in spe-
cific structures.6 71
Roger Tsien and his group'8 9] have pioneered the use of
6oO mo 1000 14o 1600 o) green fluorescent proteins as functional probes for
Raman Shift (cm ')
(S) biomolecules within cells based on the technique of fluores-
0.22 cence energy transfer (FRET). One recent application of this
0.20- approach has been to monitor sugar concentrations within
0.18- cells. Wel'l engineered a fusion protein consisting of a glu-
0.16- cose-binding protein and two different green fluorescent pro-
0 0.14- teins as shown in Figure 5. The sugar-binding moiety under-
0.12- goes a conformational change when glucose binds, such that
S0 10 it changes the distance between the GFP and YFP in a man-
0.08- ner that results in a change in FRET. Fehr, et al.,"" incorpo-
0.06- rated a similar maltose-binding protein into yeast cells. Us-
0.04 ing confocal microscopy, they were able to monitor the dis-
0.02- tribution of maltose throughout the cell, Figure 6.
0.00oo- Other techniques for monitoring the concentration of ma-
45 50 55 60 65 70 75 80 85 trials within cells are based on inserting tiny "biosensor"
pH Bulk Solution particles within cells. Raoul Kopelman and colleaguesE"12 have
( designed various materials called "PEBBLES" for measur-
ing oxygen, sugars, and pH within cells by optical techniques.
Talley, et al.,[13] have extended this approach by inserting
functionalized gold particles within cells that showed changes
in the Raman spectrum with local pH changes. Again, these
particles could be placed within cells to measure the distri-
bution in acidity within cells, Figure 7. In order to measure


Figure 7. Use of particles placed within cells to monitor
intracellular analyte concentrations by surface-enhanced
Raman spectroscopy. In this example of intracellular
monitoring, a compound that shows different Raman
spectra in its two ionic forms, is used to monitor the pH
distribution within cells."J' (a) Structure of the probe
particle and Raman spectra at different pH's. (b) The pH
behavior of Raman spectra. (c) Distribution of
nanoparticles within cells.

Spring 2006 129











The Next Millennium in ChE


local enzyme activity within cells, Weissleder, et al.,'14] in-
corporated a probe polymer with an enzyme hydrolysable
link between two fluorophores (see Figure 8).
With the increased amount of information afforded by these
imaging techniques, software to manage and display this data
in a meaningful fashion has become important. Several groups
are developing appropriate software for this purpose.15-1'
Government agencies are targeting technologies for im-
provement in intracellular imaging sensitivity. For example,
the NIH recently funded nine centers to develop cellular im-
aging techniques. Descriptions of these research efforts as
reported on the NIH Web site ( cellularimaging/index.html>) are quoted below.

OVERVIEW
The Exploratory Centers for the Development of High
Resolution Probes for Cellular Imaging support multi-
investigator teams to develop new technologies that enable
higher-sensitivity biological imaging in living cells. Each of
the nine centers willfocus on different strategies for probe
development, cellular delivery, probe targeting, and signal
detection to improve detection schemes by a factor of 10 to
100. A major emphasis of this initiative is to apply novel,
high-risk approaches to create fundamentally new probes
with enhanced spectral characteristics. The ultimate goal is
to develop probes and imaging systems that can be used to
routinely achieve single-molecule sensitivity for imaging
dynamic processes in living cells.
The centers are funded in conjunction with the NIH
Roadmap for Medical Research as part of the "New
Pathways to Discovery," an effort to advance our knowl-
edge of biological systems by building a better toolbox for
medical research. This initiative originated in NIGMS and
was later adopted by the Roadmap. NIGMS currently
supports seven of the centers as Roadmap-affiliated grants.
Funding for all nine centers is expected to total approximately
$25 million over four years ($6.8 million the first year).
1. Fluorescent Probes for Multiplexed Intracellular
Imaging. Kevin Burgess, Ph.D., Principal Investiga-
tor, Texas A&M University
Researchers from Texas A&M University and the
University of Pennsylvania plan to create novel
probe sets composed of multiplexed "through-bond
energy transfer cassettes," using multiple, linked,
donor-acceptor dye pairs that are optimized for
cellular imaging. These probes, which efficiently
absorb light at one wavelength, emit amplified
fluorescent signals at different, resolvable wave
lengths close to the red-infrared region, far removed
from cellular autofluorescence. The dye cassettes
will be specifically adapted for tracking interactions


of proteins in cells, ultimately with single-molecule
detection.
2. Sub-nm Dendrimer-Metal Nanoclusters as
Ultrabright, Modular Targeted in vivo Single
Molecule Raman and Fluorescence Labels *
Robert M. Dickson, Ph.D., Principal Investigator,
Georgia Institute of Technology
Metal nanoclusters, composed of silver and gold
atoms stabilized on organic dendrimers, exhibit
strong, size-dependent emission throughout the
visible and near-infrared spectrum. The spectral
characteristics of these clusters-their small size
(< 1 nm) and short and highly radiative


A No signal Signal *




Target
interaction






I o -

PEG P6E
S HNI NH HN



H 0 H


MI NlHa NH

PEG PE n

Figure 8. Example of a polymer probe to determine
enzyme activity within a cell. In this case the purpose
was to monitor the activity of a proteolytic enzyme
within cells. A special polymer substrate was created
that contained the peptide bond that the enzyme
cleaves and fluorophores (indicated by the circles) that
self-quench when in close proximity. When the peptide
bond is cleaved by the enzyme of interest, the
fluorophores are separated and quenching is prevented.
Thus, monitoring the appearance of fluorescence gives a
measure of local enzyme activity. Upper panel: Sche-
matic of the concept. Lower Panel: Example structure of
the probe polymer to measure enzyme activity.[14'


Chemical Engineering Education


130












The Next Millennium in ChE


lifetimes-create signals that have the potential
to be several orders of magnitude higher than
conventional labels. Grantees from the Georgia
Institute of Technology and Emory University
plan to finctionalize the nanoclusters for
attachment to different biological targets and to
develop single molecule imaging methods to
facilitate detection of the signal inside cells.

3. Single-Molecule Fluorophores for Cellular
Imaging William E. Moerner, Ph.D., Principal
Investigator, Stanford University

A group from Stanford and Kent State University
plans to synthesize and characterize a new class of
highly emissive (dicyanodihydrofuran) fluorophores
that exhibit large increases in signal when bound to
rigid surfaces. The strategy for incorporating the
probes into cells will be based upon the genetically
encoded tetracysteine-biarsenical targeting system
and then tested for single molecule specificity and
detection in bacteria.

4. Bioaffinity Nanoparticle Probes for Molecular/
Cellular Imaging Shuming Nie, Ph.D., Principal
Investigator, Emory University and Georgia Tech

A collaborative group will develop a new class of
polymer-encapsulated bioconjugated luminescent
nanoparticles with enhanced optical properties,
cellular delivery, and targeting/binding functions for
real-time and multicolor imaging in living cells. The
focus will be on core-shell semiconductor quantum
dots because of their improved brightness, resistance
against photobleaching, and simultaneous
nulticolor excitation. The researchers will test the
probes and their ability to detect them in studies
aimed at finding the subcellilar locations of p53,
nuclear factor B, and androgen receptor in living
cells.

5. Probes for Quantitative Optical and Electron
Microscopy David W. Piston, Ph.D., Principal
Investigator; Vanderbilt University Medical Center

A group from Vanderbilt will develop new fluores-
cent probes in the visible and infrared spectral
regions based on three approaches: genetically
encoded proteins, lanthanide chelates, and
nanocrystals (quantum dots). Each approach will be
tested for imaging of a protein in the plasma
membrane as well as an intracellular target.
Subcellular resolution fluorescence imaging by
widefield, deconvolution, confocal, and multi-photon
excitation microscopy will be used to implement and
test the new detection schemes based on spectral
and time-gated resolution. To reach the highest
resolution, the researchers will determine the utility


and limitations of using the new probes for direct
detection by electron microscopy for correlative
imaging.

6. Imaging Single Proteins in vivo with Quantum
Dots Sanford Simon, Ph.D., Principal Investiga-
tor, Rockefeller University

Researchers from the Rockefeller University plan to
extend and optimize an in vivo trans-splicing and
expressed-protein ligation approach to ligate
quantum dot derivatives to cytosolic or integral
membrane proteins. Their strategy includes
development of a conditional protein trans-splicing
approach that will allow probes to he ligated to the
targetfollowing a designated functional interaction.
The cellular fate of "activated" proteins will thus be
monitored by a change in the signal emitted by the
probe. The team intends to use these tools to study
exocytosis and transport through nuclear pores.

7. Light-Activated Gene Expression in Single Cells *
Robert H. Singer; Ph.D., Principal Investigator,
Albert Einstein College of Medicine

Investigators from the Albert Einstein College of
Medicine will develop a photoactivatable gene that,
upon exposure to light, begins transcription of
visible nascent chains of RNA. The ecdysone
response element and a caged, photoactivatable
ecdysone gene into which an RNA reporter has been
inserted, will be used. Gene expression will be
initiated by uncaging the ecdysone in vivo by
conventional and two-photon microscopy. The
system will be engineered into cancer cells and then
imaged intravitallv in tumors. The dynamics of
single RNA molecule movements and distribution
will be monitored.

8. Library-Based Development of New Optical
Imaging Probes Alice Ting. Ph.D., Principal
Investigator, Massachusetts Institute of Technology

The investigators plan three parallel approaches to
generate small-molecule and genetically encoded
probes that can be targeted to specific RNA or
protein sequences inside living cells. In the first,
libraries offluorophores will by synthesized in a
combinatorial fashion and then screened for their
ability to label small peptide motifs or RNA
aptamers with high specificity. In the second
approach, the natural bacterial enzyme biotin
transferase will be re-engineered to catalyze
covalent labeling of fluorescent probes to peptides
inside cells. Third, a systematic approach using a

See Inside the Cell
continued on page 139


Spring 2006











] l curriculum


ENERGY CONSUMPTION

VS. ENERGY REQUIREMENT







L.T. FAN, TENGYAN ZHANG, AND JOHN R. SCHLUP
Kansas State University Manhattan, KS 66506-5102

Today, the phrase "energy consumption" is popularly
spoken and written.111 Nevertheless, caution should L. T. Fan is University Distinguished Professor,
Holds the Mark H. and Margaret H. Hulings Chair
Sbe exercised for its continued use, especially in the in engineering, and is director of the Institute of
instruction of not only thermodynamics but also various Systems Design and Optimization at Kansas
other co s in e, i g in cmicl State University. He served as department head
other courses in engineering, including those in chemical of chemical engineering between 1968 and
engineering. 1998. He received his B.S. from National Tai-
wan University, his M.S. from Kansas State Uni-
The first law of thermodynamics teaches that energy is al- versity, and his Ph.D. from West Virginia Uni-
ways conserved in an isolated (or closed) system; it is neither versity, all in chemical engineering, in addition
to an M.S. in mathematics from West Virginia
created nor destroyed by any process, system, or phenom- University.
enon.[2-5] In contrast, the available energy analysis, which is Tengyan Zhang is a research associate in
the combination of the first and second laws of thermody- the Department of Chemical Engineering at
Kansas State University. She received her
namics, indicates that in the real world the available energy B.S. and M.S. from Tianjin University, and her
is never conserved, even in an isolated (or closed) system. Ph.D. from Kansas State University, all in
chemical engineering, in addition to a B.S. in
Even though in ideal circumstances available energy is only system engineering from Tianjin University,
theoretically conserved, the reality is that it is incessantly con- and an M.S. in computer science from Kan-
sumed, or dissipated, by any process, system, or phenom- sas State University.
enon.[6151] John R. Schlup is
presently a pro-
This consumption of available energy-or exergy- is ac- fessor in the Department of Chemical Engi-
companied by an increase in entropy, signifying the dissipa- neering at Kansas State University He ob-
tained B.S. degrees in both chemistry and
tion of available energy (or exergy) to the surrounding envi- chemical engineering from Kansas State
ronments. The dissipation of this available energy (exergy) University and a Ph.D. degree in chemical en-
r it tti r i iit tgineering from the California Institute of Tech-
reduces its potential or availability to perform useful work. nology. His current research interests include
the application of chemical engineering prin-
Similar to enthalpy, exergy is a state property of any sys- the applicatio n of chemical e engineering prin-
tem. The enthalpy as well as exergy contents of materials are of new materials from biomass.


Copyright ChE Division of ASEE 2006


Chemical En gineering Education










measured relative to the dead state, i.e., the extended stan-
dard state. It is defined by the environmental temperature,
the environmental pressure, and the datum-level substances.
Any element is part of the corresponding datum-level substance,
which is defined as being thermodynamically stable, existing
in abundance, and containing no available energy.'8 16-19] The
environmental temperature and pressure, which vary accord-
ing to time and place, are usually adopted as the datum-
level temperature and pressure; despite this, they are of-
ten specified as 298 K and 1 atm, respectively, for conve-
nience and also to be consistent with the conventionally
defined standard state.

MASS, ENERGY, AND AVAILABLE ENERGY
BALANCES
A system in which a phenomenon or process of interest
occurs is thermodynamically defined or specified by its mass,
energy, and available energy balances.8" "I 13,19-21] The follow-
ing subsections outline these three balances for system A, or
simply "the system," having multiple input and output streams
under the steady-state, open-flow conditions depicted in Fig-
ure 1, on the basis of a unit time, i.e., the rate. Figure 1 exhib-
its an isolated overall system; besides system A, it encom-


passes work and heat sources and sinks, and the entire sur-
roundings, i.e., environments. It is postulated that, except en-
ergy (enthalpy) and available energy (exergy) of mass flow-
ing through system A, other forms of energy-such as poten-
tial energy and kinetic energy-are negligible. Thus, the
changes in the enthalpy and exergy are induced by the trans-
fer of energy (between system A and its surroundings or other
systems) as heat or work. For simplicity, the aforementioned
three balances will be written around system A by referring
to Figure 1 and with the notations given in the section on
nomenclature.
Mass Balance
By taking into account both convective and diffusional
flows, the mass balance around system A yields


XMi=lMe (1)
i e
In terms of the molar flow rate, the above expression can
be rewritten as


[ (Mw) nk ]i =wI(Mw)k nk
i k J e k 1


Figure 1. Schematic diagram of an
isolated overall system encompass-
ing a steady-state, open-flow system
(system A), a heat source at tem-
perature Tm (system Ml), a heat
sink at temperature Tm2 (system
M2), a work source (system Nl), a
work sink (system N2), and the
entire surroundings at the environ-
mental temperature of T and the
environmental pressure of Po. In the
text, entering streams B,, B .... are
designated by subscript i; and
exiting streams CG, C2,,..., L-the
last being the leaking stream
(leakage)-are designated by
subscript e; the useful and leaking
streams among the exiting streams
are differentiated by additional
subscripts u and 1, respectively.


Spring 2006


Surroundings
N1Ml (To Po)


o lIQ I|(W )I |Q










Energy Balance
The energy balance around system A yields


Y.f Pkk 1+[|w1,Q i|
[ i k i


= Pknk ]+[lW2 +IQ2]+[(W)0 +IQo]} (3)
e k e_

Even under steady-state flow conditions, some parts of the
system, such as the surface of a rotating shaft of any pump,
do the work against the surroundings, or continuously gener-
ate electric charges which are discharged to the surround-
ings. This leads to the work loss, (Wx ), which will be trans-
formed into thermal energy and be trans erred to the surround-
ings as heat. The term, 1Wx ), therefore, can be combined
with the heat loss, IQ0I, thereby constituting the total heat
loss to the surroundings, IQow ; thus,


Qowl= Qol+(wx)o
This renders it possible to rewrite Eq. (3) as



I YX Pknk]]+[W +IQiI]


= 1 5 knkk +[W2|+Q2|]+IQOw
e k ),


Note that the energy content of the isolated overall system
remains invariant regardless of whether the analysis for sys-
tem A is under steady-state or unsteady-state flow conditions.
Entropy Balance
The principle of the increase of entropy, which is a mani-


Figure 2. Schematic diagram of a
steady-state thermal mixing
system, where a stream of water at
373 K and latm entering the
system at the rate of 0.5 kg-s is
mixed adiabatically and
isobarically with another stream of
water at 273 K and 1 atm entering
the system at the rate of 0.5 kg s-';
the resultant stream of water exits
from the system at the rate of 1.0
kg-s-1 at 1 atm and 323 K, resulting
from the energy balance that yields
{(0.5x 1.0x 373 + 0.5x 1.OX 273)/
[(0.5 + 0.5)x 1.0]11.3 21'


festation of the second law of thermodynamics, states: "The
entropy of an isolated system increases or in the limit re-
mains constant."2, 16] Consequently,

dS
-( >0
dt iso
The above equation can be rewritten as121

(AS)iso>0 (5)
In this expression, subscript iso stands for the isolated sys-
tem. The overall system depicted in Figure 1 is one such sys-
tem as previously indicated: It encompasses system A and its
surroundings. It is often convenient to transform Eq. (5) into
an equality by introducing a nonnegative quantity, o, defin-
ing the rate of entropy creation in the isolated overall system;
this gives rise to

(AS)iso (6)
By considering all the quantities that lead to the change in
entropy, we obtain


(AS)io =

v Y Q21 fv 1- 1 1Q I
={[ k2?knk 2e+ } 'kk I+--
e kT.k T.k

+ IQ (7)
To


As indicated in connection with the energy balance, IQow in
the above expression includes the work loss (wx)0 as well
as the heat loss IQo0 to the surroundings.

Available Energy Balance
Combining the energy balance, Eq. (4), and the entropy
creation, Eq. (7), gives rise to


Chemical Engineering Education


Surroundings
(To, Po)


Stream 1, Output
H~O, 373 K H~,O, 325 K


Stream 1,
H,O, 373 K


Stream 2
H,O, 273 K
-------


Mixer


Output
H,O, 325 K
--













{ i[ (-To)y ) nk +[iW+IQ,1- To ] (8)
i k -k Tm I


{ if (P- To)nk +[w,+IQ2 1-_ +Too


In light of the aforementioned definitions of p and y, term
( ToY) in the above equation has a connotation of the avail-
able energy of molar species, for which symbol E is coined;
it is defined as the partial molar exergy. Thus,
E=P-ToY (9)
Hence, Eq. (8) can be rewritten as



i Eknkk i +|Iw,-+ QI(1- T1 (10)
i k Tm.


=* y X Ek1nk]1 +IW2+IQ2 I- To )+Too
e k T. ,

The quantities in the brace on the left-hand side of Eq. (10)
have an implication of the total available energy input to sys-
tem A. Note that they are not equal to the quantities in the
brace on the right-hand side of Eq. (10) that have an implica-
tion of the total available energy exiting from the system.
Their difference, Too, signifies the available energy dissi-
pated by all types of irreversibility, which is transferred as
thermal energy or heat from the system to its surroundings
under the environmental conditions, as elaborated earlier.
The partial molar enthalpy relative to the dead state, P, in
Eq. (4), the partial molar entropy relative to the dead state,
y, in Eq. (7), and the partial molar exergy relative to the
dead state, e, in Eq. (10) can be estimated from the follow-
ing equations.'7 I. "17 3


TP
f=30+ pdT +v -T P


y=yo+ J CdT-iT(TT dP
To Po
TT T T aT P


E=r0+ Cp( 1-- ,dT+ i v-(T-T o -,)
To Po .P


Many of their values can also be found in various sources.'"
17.22.23]


THE MIXER EXAMPLE
This illustration is based on an extremely simple example.
It is well suited, however, for effectively conveying the main
theme of the current contribution. This example is an exten-
sion of the well-known onel" '-2 in which: no work or heat is
transferred from the system of concern to other systems and
vice versa; no work or heat is lost from the system to its sur-
roundings; no moving mechanical parts are visible on the
system; and no changes in the chemical compositions of the
streams passing through the system are detectable. Never-
theless, simply mixing two streams of water at different tem-
peratures internally leads to significant reduction of the avail-
able energy (exergy) of the system. Figure 2 illustrates the
system, which is a steady-state, thermal-mixing device, or
simply "the mixer."

Mass Balance

The term, XMe. in the mass balance equation, Eq. (1),
e.i
vanish for the mixer; thus,


Mi=Me.u or Me.u- Mi=0


Since M.u =1.0 kg-s-l and M ,=0.5+0.5= 1.0 kg-s-1, we
have i


Meu- M,=1.0-.00=0 kgs-1


As expected, the mass is conserved in the mixer and its
surroundings, collectively constituting the isolated overall
system: Water entering the mixer from its surroundings,

IM,
i
balances out exactly the water exiting from the mixer to its
surroundings, Me.u
Energy Balance

The terms, (PIn)e,d, (13n)i, W11, W21, IQ, IQ21, and
e.d e.l


Qo0w in the energy balance equation, Eq. (4), vanish when
applied to the mixer; thus,


(Pn)i=(3n)e,u or (Pn)e,u- (in)i=0 (16)
i i
On the basis of mass flow M, instead of molar flow n, the
terms in the above expression are evaluated as


Spring 2006











The first law of thermodynamics teaches that energy is always conserved
in an isolated (or closed) system; it is neither created nor destroyed by any process,
system, or phenomenon.12-5 In contrast, the available energy analysis, which is the
combination of the first and second laws of thermodynamics, indicates that
in the real world the available energy is never conserved ....


(PM)u =(25.0)(1.0)=25.0 kcal-sl-, in which


(P)eu=ao cpdt+ v-T [ dP
To Po P
=0+(50.0-25.0)(1.0)+0=25.0 kcal-kg-1

and similarly


X(PM)i =(-25.0)(0.5)+(75.0)(0.5)=25.0 kcal-s-'
1
Consequently,


(PM)e,u (PM)i =25.0-25.0=0 kcal-s-' (17)

Obviously, the energy in the mixer and its surroundings-
collectively constituting the isolated overall system-remains
unchanged; energy is conserved, i.e., never consumed. The
energy entering into the mixer from its surroundings with the
flow of water,
S(PM)i,
i
balances out the energy exiting from the mixer to its surround-
ings with the flow of water, (PM), Naturally, the first-law
efficiency of the mixer in terms of energy conservation is
(25.0/25.0) or 100.0%.

Entropy Balance
The terms,


(LkYknk J'Yknk Qi 2 ,
e,d k e,d el k Je, l m2


and IQow I/To in the expression for entropy creation, Eq. (7),
vanish when applied to the mixer and its surroundings, i.e.,
to the isolated overall system; thus,


On the basis of mass flow M, instead of molar flow n, the
terms in the right-hand side of the above expression are evalu-
ated as

(y M) =(0.080)(1.0)=0.08 kcal-s-l K-1
in which


(Y)eu=0 dT- T 0 T dP
(Y"eu 1-i J EdT J [Y- )
To Po

=0+1ln 323- 0=0.080 kcal.kg- K-1
S298 j


and similarly


(y M). =(-0.088)(0.5)+(0.224)(0.5)=0.068 kcal-s-1 K-1

As a result, we have

(AS).i =

=(Y M)eu -(Y M)i
i
=0.012 kcal-s-1 K-1
or, equivalently expressed as the most diffused form of ther-
mal energy under the environmental conditions,

To(AS)iso= ToG
=(298)(0.012)

=3.576 kcal-s- -K-1 (19)
This ascertains that the entropy change of the isolated over-
all system, accompanying whatever process or phenomenon
is occurring in the mixer, is destined to be nonnegative.

Available Energy Balance
The terms,


k IEkk knk k ,Wl, W2|, Qi(-To/Tml),
e,d k e.l k e.l


Chemical Engineering Education


(AS)iso = = (y n)e,u E( n)i
i










and IQ2I(1-To/Tm2), in the available energy balance equa-
tion, Eq. (10), vanish when applied to the mixer; thus,


X(En)i =(n)e.u+(Too) or (En)e.u (en)i=-(Too) (20)
i I
On the basis of mass flow M, instead of molar flow n, the
terms in the above expression are evaluated as

(eM) =(1.160))(1.0)= 1.160 kcal-s-

in which,

( e,u = e,.u-To(Y)e.
=(25.0)-(298)(0.088)= 1.160 kcal.kg-'

and similarly


X(eM)i =(1.224)(0.5)+(8.248)(0.5)=4.736 kcal-s-1

Hence,

(eM), (eM)i =1.160-4.736=-3.576kcal-s-1 =-(Too) (21)

Note that Eq. (21) is totally unlike Eqs. (15) and (17): Exergy
is not conserved. No work is performed on the surroundings
by water passing through the mixer and no heat is lost to the
surroundings from water passing through the mixer. In fact,
it is even assumed that the flow of water does not even en-
counter any friction during the passage through the mixer.
Nevertheless, the available energy (exergy) entering into the
mixer from its surroundings with the flow of water,


C(EM)i,

does not balance with the available energy (exergy) exiting
from the mixer to its surroundings with the flow of water,

(EM).u
In fact, it decreases, thereby correctly reflecting the irrevers-
ibility of the thermal mixing of two water streams inside the
mixer. The difference signifies the dissipation of available
energy, evaluated by Eq. (21) as -3.576 kcal-s-1: Available
energy (exergy) is always consumed, or dissipated, in the real
world. Naturally, this dissipation of available energy is the
only source of the entropy increase or creation in the isolated
overall system, whose thermal equivalent is evaluated by Eq.
(19) as +3.576 kcal-s- In essence, the energy of water
streams "available" to perform useful work is lost to its sur-
roundings in the most diffused form-thermal energy under
environmental conditions-which is totally unavailable to do
any work. This results in entropy creation in the isolated over-


all system, which can be the universe itself. In drastic con-
trast to the first-law efficiency, the second-law efficiency in
terms of available energy (exergy) conservation is merely
(1.160/4.7361) or 24.5%.
Now suppose that the mixer is externally heated at the rate,
IQ of 50 kcal-s-1 by a heater at the temperature, Ti1, of 800
K. Naturally, the temperature and the corresponding energy
(enthalpy) of water exiting from the mixer increase to 373 K
and [.0X(100-25)]X 1.0 kcal-s-l, i.e., 75kcal-s-l, respec-
tively. The energy balance around the mixer yields the first-
law efficiency of [75/(25+50)] 100% or 100%, thereby in-
dicating that it is not affected by external heating. The con-
comitant change in the available energy (exergy) of water
exiting from the mixer is from 1.160kcal-s-lto [75-(298
X0.224)] X 1.0 kcals-1, i.e., 8.248 kcal-s-'. This is obviously
an increase rather than a decrease without external heating,
thus indicating the possibility of enhancing the mixer's sec-
ond-law efficiency. In reality, however, the opposite is the
case: simply adding external heating reduces the second-law
efficiency from 24.5% to { 8.248/[4.736+50X (1-298/800)] } X
100%, i.e., 22.8%. Regarding the first law, Seider, et al.," 1
state, ". .. it can not even give a clue as to whether energy is
being used efficiently ." Moreover, according to Reistad
and Gaggioli,'241 "The second-law efficiency is the perfor-
mance parameter which indicates the true thermodynamic
performance of the system."

CONCLUDING REMARKS
With the aid of a deceptively simple example, it has been
unequivocally demonstrated that energy is conserved, i.e.,
never consumed; what is always consumed, or dissipated, is
available energy (exergy), which is the essence of this brief
contribution. This simple example also succinctly indicates
that an attempt to rigorously assess the sustainability of any
process or system should be based firmly upon the thermo-
dynamics, in general, and the evaluation of the system's sec-
ond-law efficiency based on available energy (exergy), in par-
ticular, as practiced in the EU community'251 and the Canton
of Geneva in Switzerland.126

ACKNOWLEDGMENT
This work was supported by U.S. Department of Energy
under Contract DEFG36- 011D14126.

NOMENCLATURE
A system A
cp specific heat, J mol '. K`'
M mass flow rate including both convective and diffu-
sional flows, kg s'
Mw molecular weight, g mol'
N molar flow rate including both convective and diffu-


Spring 2006













sional flows, mol s-'
P pressure, atm
Q0o heat loss to the environment per unit time, J s-' or kcal -
s5

IQow total heat loss to the environment per unit time, J s-' or
kcal s-'
Qi heat transmitted from system MI to system A per unit
time, J s-' or kcal s

IQ1 heat transmitted from system A to system M2 per unit
time, J s-' or kcal s-'
S entropy, J K-

s partial molar entropy, J mol-' K-'
T temperature of system A, K
Tm, temperature of system Ml, K
T n temperature of system M2, K
v volume, m3

IWo0 work lost to the surroundings per unit time, J s-' or kcal
S-1

W l work supplied from system N1 to system A per unit
time, J s-' or kcal s '

IW2I work supplied from system N2 to system A per unit
time, J s-' or kcal s'

(Wx)0 work lost to the surroundings except that due to
expansion of the boundary of system A per unit time,
J s-' or kcal s-'
Greek letters

p partial molar enthalpy relative to the dead state, J mol' or
kcal kg-'

P, partial molar chemical enthalpy, J mol' or kcal kg-'

E partial molar exergy, J mol-' or kcal kg-'
Eo partial molar chemical exergy, J mol' or kcal kg

y partial molar entropy relative to the dead state, J mol-' k'
or kcal kg-'-K-

Yo partial molar chemical entropy, J mol- k' or kcal kg '.K-'

Co created entropy per unit time, J sec i' k- or kcal sec-.'K-'

Subscripts
0 dead state
e,u useful output streams
i input streams
iso isolated system
k material species
1 leakage

Superscript
0 standard state


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sign Principles, John Wiley and Sons (2004)
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Chemical Engineering Education












The Next Millennium in ChE


Inside the Cell
continued firo page 131


combination of rational design and screening of
mutant libraries will be used to create green
fluorescent proteins with improved photophysical
properties.

9. Genetically Targetable Labels for Light and EM *
Roger Y. Tsien, Ph.D., principal investigator,
University of California, San Diego

A team from the University of California and the
University ofIllinois plans a series of approaches to
generate fluorescent proteins with increased
photostability and higher quantum yield, to explore
quantum dot construction and targeting, and to
further develop tetracysteine labeling techniques for
light and electron microscopy. The team's plans also
include exploring genetically targetable labels with
long excited state lifetimes based on lanthanide and
transition metal luminescence as well as directed
evolution of fluorescent proteins to improve their
photophysical properties. A major goal of this team
is to enable direct visualization in the electron
microscope of the same molecules that have been
tagged, observed, and dynamically tracked in the
light microscope.

Now that breakthroughs are under way to provide specific
information on the functioning and control of organelles, a
unique opportunity is evolving for chemical engineers to use
this mechanistic information to design new integrated
biocellular operations and processes.

It is likely that exceptional progress will be made in the
next decade to reveal the physical chemical phenomena that
govern the organization and behavior of the biochemical pro-
cessing units within cells. Naturally then, new concepts of
process design will emerge for the chemical/biochemical in-
dustry through the research efforts of biochemical engineers.
As this knowledge becomes available it will be incorporated
into the graduate-program courses in chemical engineering
departments as an enhancement to courses such as systems
biology, bio-MEMS, biochemical separations, bioprocess
engineering, and pharmaceutical biotechnology. One can ex-
pect a dramatic evolution in process technology that will be-
come an important capability for future chemical engineers,
especially for high-value, low-volume products.


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9. Zhang J.. R.E. Campbell. A.Y. Ting, and R.Y. Tsien, "Creating new
fluorescent probes for cell biology." Nature Review Mol. Cell Biol.,
(12) 906-18 Dec. 3 (2002)
10. Ye. K.. and J.S. Schultz, "Genetic engineering of an allosteric-based
glucose indicator protein for continuous glucose monitoring by fluo-
rescence resonance energy transfer." Anal. Chem. (75) 3451-3459
(2003)
11. Fehr. M., W.B. Frommer, and S. Lalonde, "Visualization of maltose
uptake in living yeast cells by fluorescent nanosensors," Proc. Natl.
Acad. Sci. USA (99) 9846-51 (2002)
12. Buck, S.M., Y.L. Koo. E. Park. H. Xu, M.A. Philbert, M.A. Brasuel,
R. Kopelman. "Optochemical nanosensor PEBBLEs: photonic explor-
ers for bioanalysis with biologically localized embedding," Current
Opinion in Chem. Biol. (8) 540-546 (2004)
13. Talley. C.E., L. Jusinski, C.W. Hollars. S.M. Lane, and T. Huser, "In-
tracellular pH Sensors Based on Surface-Enhanced Raman Scatter-
ing," Anal. Chem. (76) 7064-7068 (2004)
14. Weissleder. R.. C. Tung, U. Mahmood, and A. Bogdanov Jr., "In vivo
imaging of tumors with protease activated near-infrared fluorescent
probes." Nature Biotechnology (17) 375 (1999)
15. Eils, R., and C. Athale, "Computational imaging in cell biology," J.
Cell Biol. (161) 477 (2003)
16. Gerlich, D.. J. Mattes, and R. Eils, "Quantitative motion analysis and
visualization of cellular structures." Methods (29) 3-13 (2003)
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tive cell biology with the Virtual Cell," Trends in Cell Biol. (13) 570
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Tool for Visualization of Multidimensional Biological Image Data,"
Traffic (5) 411-417 (2004) 0


Spring 2006










Class and home problems i


GAS PERMEATION COMPUTATIONS

WITH MATHEMATICS


HOUSAM BINOUS
National Institute of Applied Sciences and Technology 1080 Tunis, Tunisia


Gas separations using membranes have received
increased attention by the scientific and industrial
community. This technique is now at a mature stage
and can compete with more common techniques used in the
petrochemical industry such as cryogenic separation, gas ab-
sorption, and pressure swing adsorption. The nonporous mem-
branes can be organic or inorganic. They are classified ac-
cording to their thermal and chemical stability as well as their
selectivity to different gases. The mechanism of separation is
based on the differences in the dissolution and diffusion of
gases in the nonporous membrane. The separation of hydro-
gen from other gases such as carbon dioxide and carbon mon-
oxide in syngas plants is a very important industrial applica-
tion of this technique. Acid gas (CO, and H2S) elimination
from natural gas is another application of membrane separa-
tions. Very often one is confronted with the separation of
multicomponent mixtures. Thus, we consider a hypothetical
ternary mixture, in the first part of the paper, to show how
one can obtain the permeate and reject compositions as well
as the membrane area.


SEPARATION OF A TERNARY MIXTURE
A ternary feed mixture has the following composition and
flow rate:

XfA=0.25, xfB=0.55, xfC=0.2 and qf=1.0xl04 cm3 (STP)/s
Since the stage cut, defined as the fraction of the feed al-
lowed to permeate, is 0=0.25, the permeate flow rate, q is
equal to 0.25 x 10 cm3(STP)/s. The permeabilities, expressed
in cm3 (STP) cm/(s cm2 cmHg), of components A, B, and C


Housam Binous is a full-time faculty mem-
ber at the National Institute of Applied Sci-
ences and Technology in Tunis. He earned
a Diplome d'ingenieur in biotechnology from
the Ecole des Mines de Paris and a Ph.D.
in chemical engineering from the University
of California at Davis. His research inter-
ests include the applications of computers
in chemical engineering.
V^ '


Copyright ChE Division of ASEE 2006
Chemical Engineering Education


The object of this column is to enhance our readers' collections of interesting and novel prob-
lems in chemical engineering. Problems of the type that can be used to motivate the student by
presenting a particular principle in class, or in a new light, or that can be assigned as a novel
home problem, are requested, as well as those that are more traditional in nature and that eluci-
date difficult concepts. Manuscripts should not exceed 14 double-spaced pages and should be
accompanied by the originals of any figures or photographs. Please submit them to Professor
James O. Wilkes (e-mail: wilkes@umich.edu), Chemical Engineering Department, University
of Michigan, Ann Arbor, MI 48109-2136.
<__________________________________________










are equal to

PA=200x10-l, P' =50x10-10, and Pc=25 x10-0.
This mixture is to be separated by a membrane with a thick-
ness t=2.54x 10" cm. Pressures on the feed and permeate sides
are p,=300 cmHg and p,=30 cmHg. We will use the com-
plete-mixing model to compute the permeate and the reject
compositions as well as the membrane area. The three rate-
of-permeation equations are:

qpypi =- Am(phxoi-piypi) for i=1,2,3 (1)

The three material balances equations written for compo-
nents A, B, and C are:
1 0
xoi = xfi- ypi for i=1,2,3 (2)
1-0 1-0
Finally, we have an additional relation that is the summa-
tion rule for mole fractions:

1yPi=1 (3)
i=l
Equations 1 through 3 are labeled rate, matbalance, and
summation, respectively. We need to enter these equations in
the Mathematica notebook'21 and call FindRoot as follows:
FindRoot[ ratell, rate2, rate3,
matbalancel, matbalance2, matbalance3,
summationl, {yp,A 0.2}, {yp, 0.2}, {yp,
0.2}, {A,, 10o6}, {XoA, 0.2}, {XOB, 0.2}-
{xc, 0.2}]


qf Xf


qo xo
qp yp


(a) complete mixing model




0Oqf yp (1-O) qf xo
qf Xf -~

dAm

(c) countercurrent flow


FindRoot uses different root search techniques that can be
selected by the user. If one specifies only one starting value
of the unknown, FindRoot searches for a solution using New-
ton methods. If the user specifies two starting values, FindRoot
uses a variant of the secant method, which does not require
the computation of derivatives. All this is handled internally
by Mathematica, making the solution of complex systems of
nonlinear algebraic equations very easy. We get the follow-
ing solution for the permeate and reject compositions and the
membrane area labeled A:
{ypA- 0.455281, yp-> 0.450286,
Ypc 0.0944335,
A -3.54176X106, xOA, 0.181573,
xB- 0.583238, xoc0-- 0.235189}
which is in agreement with results using a tedious iterative
technique."]

ENRICHMENT OF AIR IN OXYGEN
USING MEMBRANE PERMEATION
In this section, we present the study of the enrichment of
oxygen in air using a single-stage membrane module. This
problem has been treated first by Walawender and Stern''
and later by Geankoplis.'" The binary mixture, A (oxygen)
and B (nitrogen), has an ideal separation factor, the ratio of
the permeabilities of the two species, a* =10. The perme-
ability of oxygen is PA=500x10-10 cm3 (STP) cm/(s cm2
cmHg). The membrane is more permeable to oxygen and has


Sqf yp



qf Xf q (1-) qf xo

dAm

(b) cross flow





0 qf yp
qf Xf (1-) qf xo

dAm
(d) co-current flow


Figure 1. Flow patterns.
Spring 2006










a thickness t=2.54X 10-3 cm. The stage cut, 0, is set equal to
0.2. The values of the pressures in the feed and permeate
sides chosen by Geankoplist" are p,=190 cmHg and p,=19
cmHg, which give a ratio of pressures, r, equal to 10. The
feed rate and composition are given by:
xfA=0.209, x,=0.791 and q,=1.0x 106 cm3 (STP)/s.
The different flow patterns, shown in Figure 1 (previous
page) and considered in this study, are complete mixing, cross-
flow, countercurrent flow, and co-current flow. Calculations
for each flow pattern will be presented in a separate sub-
section.
1. Complete-Mixing Case
The permeate mole fraction, yp, is the solution of the fol-
lowing quadratic equation:


o [xxo- P yp
Yp = Ph J (4)
1-yp ( -(xo)_ P, )(1-yp)


where the reject composition, xo, is given by the mass bal-
ance:

Xf -yp
xo= (5)
1-0

We also define a* and r by a* = PA/ PB and r=P/P.
The membrane area is then obtained using Equation (6):

Am Ofyp (6)
PA )PhX| Yp
A -/(phxo-plyp)

For our particular problem, we find the following results
using Mathematica:
yp=0.5067, x0=0.1346, and Ao1=3.228 108cm2.
These results are in agreement with those found by
Geankoplis."l'
2. Cross-Flow Case
The local permeate rates over a differential membrane area
are given by


-ydq= -(ph x y)dAm (7)



-(1-y)dq= (ph(1-x)-p,(1-y))dA (8)

In addition, we can derive Equation (9) from total and com-
ponent mass balances:


ydq=d(qx) (9)
These three governing equations are solved simultaneously
using the Mathematica built-in function called NDSolve. The
following boundary conditions are used:

qAm =0=qf, XAm=0 XfA and yAm=0YPi

where ypi is obtained by solving the quadratic equation


ypi Ph J

yp (I-xfA)-p- ypi)


The command used in the notebook to solve the system of
ODEs is:
myODEsoln[ f]
NDSolve [ {y[A] D [q[A] {A, 1}]==
D[Eq[A] x[Am], {Am, 1} ],
-y[Am] D[q[A], {A,1}]== P'A/t (Ph X[A]
Ply [A] ) ,
(1- y[A] ) D[q[Am], {Am, }]==
P',/t+(ph(l- X[A) p1(1- y[A])), x[0]
== xf,
y[0] == ypi,q[0] == q,, {x[Am]
y[A ],q[A] }, {Am, 0, n}]
We use FindRoot to get the total membrane area. In fact,
we must satisfy the following condition: 0=0.2 where the
stage cut, 0, is given by 6=(qf-qled)/qf.
The Mathematica command is written as follows:
qend[2Q_?NumericQ] : =Flatten[(q[AJ /.
myODEsoln[Q] )/.A -> ]
Aso = FindRoot [(qf- qend[ ] )/qf==0,
{(,2 10^8,3 10^8}, Maxlterations->1000];
The final result is a membrane area and a reject composi-
tion equal to: Aso=2.899x 108 cm2 and x0=0.1190. A compo-
nent balance, 0y +(1- 0)Xo=xfA, can be used to obtain the per-
meate mole fraction and we find that y =0.5688. Our approach
gives similar results as those given by Geankoplist' but is far
less tedious and more accurate. We can check our results by
integrating y(Am) forAm varying from 0 to A,.,, achieved with
the command:
Integrate [First [y [A] / .myODEsoln [ /
.Ao]] /. Am-area,
(area, 0, Q /.Ao}]/Q/.Aol
We get yp=0.5634, a value in agreement with the previous
result. Since numerical integration is used, the later value of


Chemical Engineering Education










yp is less exact. In Figure 2, we plot the mole fraction in the
permeate and feed sides in the membrane module. Similar
figures can be easily drawn for the other flow patterns using
the graphical capabilities of Mathematica. Figure 2 clearly
shows that the oxygen mole fraction in the feed side of the
module varies from the inlet value, x,=0.209, to the reject
value, xo=0.1190.
3. Countercurrent-Flow Case
The flow diagram for the countercurrent-flow pattern is
shown in Figure 1. Both streams are in plug flow. The two
governing equations have been derived by Oishi, etal.,1' and
Walawender and Stem 31:

Sqpt dx x-y 1{(1-x)a*(rx-y)- x[r(1-x)-(1 -y)]}
otPB Am y-xo
(11)


S dym x {(- y) (rx- y)- Y[r(1- x)-(1-Y)]}
pqo dA, x-xO
(12)
where qo=(1-6)q,. The following boundary conditions

X m=OX0 and YA=O=Yi

are used where y is the solution of the quadratic equation:


a[xo- ]i
Yi (. xo) PhI y)
1-yi (1-xo)_ Pl (1-yi)
Ph )


We use L'Hopital's rule to compute the derivatives at Am=0
because they become indeterminate when x=xo. This is per-
formed as follows:



Mole
fractions ,,



04
04



02


0 5xlO7 IxlO' 15x10' x 2xl(f 1 25.x l '
Am, (cmn)

Figure 2. Mole fractions of reject and permeate.
Spring 2006


(dy \ (xo-Yi)r[ -y(a*-1)]
dAm Am =0 q {(xo-Yi,)(a* )(2yi-rxo-l)-r}
(Am=0
P|PB f dxa^


(14)


Sdx c (rxo-yi)(xo-yi) (15)
dA-m o t Yi
PIPB)
These two differential equations can be solved simulta-
neously using NDSohle. We enter the equations using an If
statement to take into account the derivative expression when
A ->0:
eql[a_] :=D [x[A] {A, 1}] ==
If[Am == 0,
Evaluate[
(pP') / (q0 t) a (xo ph/ p, yi) (xo- yi)/
yi /.
t-> 2.54 10^-3/. Ph -> 190 /. p -> 19/.
a -> 10/.
P' -> 50 10^-10/. qo -> 8 10^5 /
.xo- a] ,
Evaluate[
(PiP'B)/(qo t) (x[Am] y[Am)/ (y[A -
xo)
((1- x[A] ) a (p/p, x[A] y[Am])-
x[AJ (Ph/p, (1-x[A] ) (l-y[Am] ) ) )/.
t-> 2.54 10"-3/. p -> 190 /. p1 -> 19/.
a -> 10/.
Ps -> 50 10^-10/. qo -> 8 10^5 /
.xo->a] ]
Since the value of the reject mole fraction, xo, and the total
area, Am, are unknown, we use FindRoot to solve for these
two unknowns so that the mole fraction of oxygen in the feed
is 0.209 and that the material balance for component A is
verified:

X Aol =xfA and OyplAsol +(1-O)XOXAf
Following the treatment of Walawender and Stern,'13 we
set the area equal to zero at the outlet of the gas separation
module. Thus, the sign of the membrane area obtained using
this approach is negative and must be reversed. We get the
following results: Aoi=2.859X10" cm2, yp=0.5763, and
xo=0.1171. We find a smaller membrane area and reject mole










fraction and a higher permeate composition.
4. Co-Current-Flow Case
The governing equations"3 are derived in a similar fashion
to the preceding case.

qft dy x
(- {(y)*(rx-y)-[r(1-x)-(l-)]}
p1PB dAm x-xf
(16)

qft dx x-y )a(rx-y)x[r(-x)-(-y)
pPH dAm y -xf
(17)
The following boundary conditions must be used:
XIAm = =XAf and yA, = Yi". The value of y, is a solution of
the following quadratic equation:


Yi [Xf-( Ph yi
Yi_ [ Kh L (18)
1- y )


Inspection of Equation (16) shows that the derivatives are
indeterminate when Am 0. We use L'Hopital's rule to get
expressions for the derivatives at Am=0 as follows:


Sdy
dAm Am=0o


(xf -yi)r[a* -yi(a*- )]

qft {(xf-yi)[(a*-l)(2yi-rxf-1)-r
piPB ( dx )


dAm) o

(19)


dx 1 a*(rxf-yi)(xf-yi) (20)
dAm )Am=0 ft Yi


The value of the total membrane area is found using
FindRoot to satisfy the material balance for oxygen:
yp Asol +(1- )xo =xAf. The membrane area, permeate com-
position, and reject mole fraction are equal to: Ao,=2.955 X 108
cm2, yp=0.5584 and xo=0.1216.
5. Comparing the Different Flow Patterns
The membrane areas are equal within 10%. The smallest
membrane area is obtained using the countercurrent flow
pattern. The countercurrent case requires a smaller membrane
area because the driving force for permeation (the composi-


tion difference between permeate and feed sides) is higher
than in the other flow patterns. The complete-mixing model
gives the highest membrane area. The reject mole fractions
and the permeate compositions obtained for the four cases
studied show similar trends. The most efficient flow pattern
is the countercurrent mode. In fact, the order of efficiency is
the following: countercurrent flow > cross-flow > co-current
flow > complete-mixing model. Reducing membrane area
has a major impact on capital investment costs. Thus, the
countercurrent flow pattern is the optimal design choice. Other
relevant parameters for reducing membrane area are thick-
ness and permeability of the membrane and operating pres-
sure, which will affect operating costs as well.

CONCLUSIONS
In this study, we showed how simple Mathematica com-
mands[2' can be used to solve problems that required tedious
iterative techniques or complicated programming skills. We
present the solutions of two problems proposed by Professor
Geankoplis.111 We extend this author's work to the counter-
current and co-current flow patterns. These problems are given
to the junior and senior students of the National Institute of
Applied Sciences in Tunis as small research projects. The
students excel in these type of problems despite the fact that
they do not have prior knowledge of Mathematica.

NOMENCLATURE
A membrane area
Pi permeability of component i
Ph feed side pressure
p, permeate side pressure
qf feed flow rate
qp permeate flow rate
q. reject flow rate
t membrane thickness
r ratio of pressures of feed and permeate sides
x, feed mole fraction of component i
xo reject mole fraction
y, permeate mole fraction
a* separation factor
0 stage cut

REFERENCES
1. Geankoplis, C.J., Transport Processes and Unit Operations, 3rd Ed.,
Prentice Hall, Upper Saddle River, NJ (1993) (example 13.5-1, page
771 and example 13.4-2, page 767)
2. ?search_results=1;search_person_id=1536>
3. Walawender, W.P., and S.A. Stem, Separation Science, 7 5, 553-584
(1972)
4. Oishi, J., Y. Matsumura, K. Higashi, and C. Ike, J. At. Energy Soc.
Japan, 3, 923 (1961) O


Chemical Engineering Education


























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PAGE 1

= (:) ... ... c:s I.I ::s r..i b() = ... ... 'II 'II = ... b() = r..i ... !> 'II ... I.I (:) t,:i = c:s I.I ... ... "' 'II ... E: 'II 'II = ... r:f b() (:) = ... r..i "' ... ... ;:,. c:s ... I.I ... b() E: = 'II ... ,i:: ... I,,) 'II 'II = ... 'II b() ... = ::s r..i ... ... .... ... c:s "' = I.I ... ... E: = 'II c:s ,i:: I.I I,,) ... ... 'II E: chemical engineering education of the University of Washington SPE e l AL ISSUE: THE NEXT MILLENNIUM IN CHEMICAL ENGINEERING Introduction (p. 99) Hrenya, Fogler A Vision of the Curriculum of the Future (p. 104) Armstrong Teaching Engineering in the 21st Century with a 12th-Century Teaching Model: How Bright Is That? (p. 110) Felder A Different Chemical Industry (p. 114) Cuss/er Crystal Engineering: From Molecules To Products (p. 116) Doherty Inside the Cell: A New Paradigm for Unit Operations and Unit Processes? (p. 126) Schultz Design Projects of the Future (p. 88) ............................................................... Shaeiwitz, Turton Energy Consumption vs. Energy Requirement (p. 132) .................................. Fan, Zhang, Schlup Gas Permeation Computations with Mathematica (p. I 40) ............................. Binous A Whole New Mind for A Flat World (p. 96) ................................................. Felder Tulan e U n iversity

PAGE 2

INVITED GUEST E D ITO R IAL For the sake of argument // the conventional lecture is dead, why is it alive and thriving? Straight lecturing is the least effective way to im prove s tudent learning. Students tend to remember 10 to 50 % from pa ssive" involvement in the learning proce ss (we remember about 10 % of what we read ; 20 % of what we hear ; 30 % of what we see; and 50 % of what we hear and see). Students remember 70 and 90 %, however if they are "ac tively" involved (we re member about 70 % of what we say and 90 % of what we say and do) Also, st udents in learning environ ment s where lecturing dominates become more "rote learner s"; students learning in problem-based or co operative learning environments become more deep learners. Recently re sea rch was done on the effectiveness of updating courses for medical doctors. Those courses that were lectures produced no change in practice. Courses that included active learning components did produce a change in practice Since we usually want to help students remember and s inc e we want graduates who are deep learner s in stea d of rote learner s, why do faculty st ill give 50mjnute le c ture s of teacher talk ? Why do univer s itie s build more lecture auditoriums-instead of flat-floor learnin g environments with movable chairs and table s that a re more conducive to cooperative and active learning? Why do courses in teacher trainin g focus on how to lecture, and how to lecture to large classes, instead of how to u se active learning cooperative learning or problem-based learning? Why are fac ulty called "lecturers "? Perhaps the answer is that lectming is relatively easy most of u s learned from lectures (so what's wrong with the lecture ?), and each of us gets a sense of power and u se fulne ss when we walk into a lecture hall and all eyes look at u s and wait to write down our every Don Woods CEE Publication s Board thought s. Perhap s that s the only way that we see that we can cover the material-but our role i s to uncover material so that st udent s learn Perhap s we don t want to s top lecturin g even though we know there are other options available. So if I currently use straight lecture s, what might I do ? One simple way to change from s traight lecturing to more effective learning environments is to never have more than 20 minutes of teacher talk Boredom se t s in after 20 mjnutes. A suggestion i s to u se a timer se t for 20 mjnute s to remind you to s hift from teacher talk to some activity. Examples of active" activities include : Ask individuals to write refle c tions (2 min.) then discuss with a neighbor (90 s ec.) Ha ve students turn to their n e ighbor and say: "Did yo u und e rstand that ?" D o y ou b e li eve that ?" Th e k ey point so far is ... A pra c ti c al appli c ation of this stuff is .... Ask students to compare or rework not es Use Talk Aloud Pairs Probl e m Sol ve, or TAPPS Other options include u s ing rounds (w her e s tu dents sit in circles of about four or five and each com ment s for about 30 seco nds on a topic you po se) or using cooperative learning groups. The s traight lecture with 50 mjnute s of teacher talk really doesn't improve student learning It 's time to change. 0

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EDITORIAL AND BUSINESS ADDRESS: Chemical Engineering Education D e partment of C hemical Engineering University of Florida Gaine sv ille FL 32611 PHONE a11d FAX: 352 -392-0 86 1 email : cee@c h e 11j1 edu EDITOR Tim Anderson ASSOCIATE EDITOR Phillip C. Wankat MANAGING EDITOR Lynn Heasle y PROBLEM EDITOR James 0. Wilkes U Mi c higan LEARNING IN INDUSTRY EDITOR William J Koros G e or g ia I n s titut e of Te c hnolo gy PUBLICATIONS BOARD C HAIRMAN E. D e nd y Sloan Jr Colorad o S c hool of Min e s VICE C H A IRM AN John P. O Connell Uni ve rs i t y o f Vir g ini a EMBERS Kristi A n set h Uni ve r s i ty o f Colorad o Pablo Deb e n e d etti Prin c et o n U ni ve r s i ty Dianne Dorland R o wan Univer s ity Thomas F. Edgar Uni v er s it y o f T e xa s at Au s tin Richard M Felder No rth Car o lina Stat e U ni ve rsi ty Bruc e A Finlayson U ni ve r s it y o f Washin g t o n H Sc ott Fogler Uni ve r s it y o f Mi c hi g an Carol K. Hall North Car o l ina Star e Uni v ers i ty William J Koro s G eo r g ia I n s titut e of T ec hn o l ogy Steve LeBlan c U ni ve r s it y o f T o l e d o Ronald W. Rou ssea u G e or g ia I n s titute o f T ec h no l ogy Sta nl ey I. Sandler U ni ve rsity of Dela w ar e C. Stewa rt Slater Rowan Univ e rsity Donald R Woods M c Masr e r U ni ve r s i ty Sprin g 200 6 Chemical Engineering Education Volume 40 Number 2 Spring 2006 DEPARTMENT 80 Tulane: K a trin a a nd its Aftermath, Brian S Mit c hell John A. Prindl e, H enr y S Ashbau g h Vijay T J ohn EDUCAIOR 74 Eric M. Stuve of the U ni ve r si t y of Washington Bruce A. Finlayson CURRICULUM 88 De s i g n Proje cts of th e Future J os e ph A. Sha e iwit z R i c hard Turton 132 Energy Consump ti o n vs. E n ergy R eq uir ement L.T Fan T e n gy an Zhan g, John R S c hlup CLASS AND HOME PROBLEMS 140 Gas Permeation Compu t atio n s with Ma th emat i ca, H ausam Binous RA N DOM THOUGHTS 96 A Whole New Mind for A Flat World Ri c hard M Feld e r THE NEXT MILLENNIUM I N CHEMIC A L ENGINEERING 99 Introdu ct i o n Ch ri stine M. Hr e n y a H. S c ott F og l e r 104 A Vision of th e C urri c ulum of th e F utur e R ober t C Armstrong 110 Teaching Engineering in the 2 1 st Century with a 12th-Century T eac hin g Model: H ow Bri g ht I s That ? Ri c hard M F e ld e r 114 A Di ffere nt C h e mi ca l Indu s tr y E.L. Cussler 116 Crys t a l Engineering: From Molecules To Produ cts Mi c ha e l F. Doherty 126 Inside t h e Ce ll : A New Paradigm for Uni t Operations a nd U nit P rocesses? J e r o m e S S c hult z C H EM I CAL ENGINEERING EDUCA TIO N ( I SSN 0009-2479 ) is publi s h ed quarterly by th e C h e mi ca l E 11 gi 11 ee rin g Dil>isio11 A m e ri can Soci e ty fo r E n g in ee rin g Edu c a ti o11 a11d is edited at th e U ni ve r s i ty of Florida Correspo11dence r eg ardi11 g e diton al matt er c i rc ulati o11 1 a11d c ha11 ges of address s l wuld be se 11t t o CEE C h e mi ca l E 11 gi n eeri n g Department U ni ve r s it y of F l orida Gai n esv ill e, FL 326 11-600 5. Copyrig ht 2006 by tir e C h e mi ca l Engineering Division A m erica11 Society/or E 11 g i11e e ri11 g E du catio n. Tire s t a t e m e nt s and opinions ex pr essed in tlri s p e ri o di c al are tho se of th e w rit e r s and not 1tecessaril y those of th e C h E Division ASEE w hi ch body as s um es 11 0 responsibility fo r them. Defective co pi es replaced if notified wit hin 120 da y s of publicatio1t Writ e for iltformah o n on sub sc ription cos t s and for back c opy c osts and availabi li ty. POSTMASTE R : S e nd addr es s cha1tge s to C lr e mi c al E 11 gi t1 eeri11g Education, C lr emica l Engineering Department U ni ve r sity of Florida Gai n esv ill e FL 32611-6005 Periodicals Po s tag e Paid at Gainesville, Florida a nd additional post offices. 7 3

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.tailll5111ii4.._e_d_u_c_a_to_r ______ __.) Eric M. Stuve of the University of Washington BRUCE A. FINLAYSON University of Washington Seattle WA 98195-1750 E ric is one of the few people I know who watches the Indianapolis 500 race. That's a legacy from growing up in Indiana. He was born in Montana but s oon afterward his parents moved the family to the Midwest liv ing in Michigan Wisconsin, and Indiana. It's typical of Eric that he retained hi s affection for that down-home pastime even as he embraced the intellectual challenges of studying the sciences and pursuing a professorial career. Eric has always been one to run his own race. Since he was living in Milwaukee as a high school senior, attending the University of Wis consin, Milwaukee, was a natural choice. After one year, and upon the advice of Charles G Hill, he transferred to the Madison campus where he excelled. In preparing for graduate schoo l Eric was fortunate to receive good advice from the Wisconsin professors. Ed Lightfoot reviewed fac ulty at a number of schools and Hill for whom Eric was doing an undergraduate research project cautioned about getting involved in surface science as it was a lot of u l trahigh vacu u m physics. It was good advice, but Eric had other plans. Eric's research began at Stanford, where he worked with Bob Madix on surface reactions in u l trahigh vacuum on p l ati num and silver. He found the physics was fun Following his Ph.D. ( 1984) he went to Berlin with an Alexander von Humboldt Fellowship in the Fritz-Haber-Institut der Max Planck-Gesellschaft, and it was in Berlin that he met Monika who was born and raised in East Germany. They wed in 1985 which was a l so the year Eric came to the University of Washington, where he i s now c hair of the Department of Chemical Engineering. Eric i s committed to in vo lving s tudents in innovative projects in both de s ign and research, and he bring s consider able enthusiasm, humor and a fundamental understanding to all his interactions with the s tudents TEACHING AND RESEARCH With Eric, teaching and re sea rch are in se parable Learning by teaching ha s se rved him well. He reports that in his first year teaching the process de s ign course, he learned to put Cop y ri g ht C hE Di v i s i o n o f ASEE 2 00 6 74 C h emica l Engineerin g Education

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into per s pective what he did at the molecular level helping him as an e ducator and researcher. Lik ewise, teachin g hi s first course in graduate thern1odynamic s challenged him to make the homework problem s relevant-and he s uddenly saw how he co uld bring electrical e n gineer in g and chemical en gineering to the course. Furthermore h e says, he had one of tho se eureka moment s: I could do thi s." Thus spawned his work on hi g h electric fields, which ran for 10 years and provided important data no one else had: A field ion microscope was u sed to st ud y field-induced s urface chemistry at very high electric fields ( 100 MV /cm); adsorp tion and reaction of water on s harp ( 10-100 nm ) field emitter tip s elucidated the basic ioni za tion of water to hydronium ions and hydroxide ion s induc ed by the electric field and the s tructure of water at the interfac e This information is u sef ul for rational catalyst design for fuel cells, understanding ice chemistry in oceanic and atmo sp heri c environments (ozo ne hole chemistry), and development of ultr a-ca pacitors for high energy/high-power electrical de vices. As he began hi s research at the University of Washington, Eric branched out into electrochemical probl e m s as well, pro viding the underlying support for hi s l ater work on fuel cells. While in Berlin he had learned how to apply electrochemi cal concepts to surface reaction s on metal electrodes inlmersed in liquid s. He then built equipment that enabled comparison of electrochemical and gas solid s urface phenomena under nearly identical conditions. Thi s helped elucidate the impor tance of potential in reaction s at the fluid-solid interface. The electrode s urface s could be analyzed u s ing thermal de so rp tion, low-energy electron diffraction, Auger and X-ray photo electron spectroscopy, and secondary ion ma ss s pectrometry. For hi s work, Eric was chosen as an NSF Presidential Young Spr in g 2006 Eric and three very happy grads let loose with some leis follow ing commencement ceremonies on campus. Investigator. Since his work was mostly done under high vacuum, h e joined the American Vacuum Society (AVS) and, over time became a director trustee, and chair of the Inve s tment Advisory Committee In hi s work with investments, he taught the other scientists the concept of net present value, which-fittingly for Eric-he had learned b y teaching the undergraduate de s i g n course. He is currently a fellow of the AVS. FUEL CELL LOCOMOTIVE On e day Eric and a prof esso r from Aeronautics and Astro nauti cs ( Reiner Decher ) came to see me in the chair 's office. They propo se d making a fuel-cell driven l ocomotive, amuse ment park size. Eric's interest was in the fuel cell, and Reiner 's passion was with trains They explained that combining the efficiency of a train for transporting goods with the efficiency of a fuel cell would make an ideal sys tem. As we talked, the image of having a s mall train circle Fro s h Pond during Engineering Open House came to mind as a great crow d pleaser. Ex cept ... the thought of inexperienced undergraduates han dling hydrogen in a venue with thousands of middle sc hool kid s was a scary one, to say the lea s t. But Eric was undeterred, and had other ideas as well. Thus through his determination and vision was born one of the co untr y's be s t centers for fuel cell education, now encom passing several professor s and several coursesund ergradu ate a nd graduate, one of which is delivered as televised dis tance learning. The goal of the Fuel Cell Locomotive Project (whic h be gan in 1996) was to produce a fuel cell system, fully con tained, that co uld provide 10 kW of power at 100 V to a pro ton exchange membrane sys tem. The fuel cell would be the prime mover for an 18-inch-gauge locomotive ( one-third size) that would pull two passenger coaches Eric's plan to demon s trate the train se tup at an Engineer ing Open House got the green light and it became a com bined project involving st ud ents and faculty from many dis75

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Hey, long hair was in then left. Eric and Monika on their wedding day in 1985, right. Eric's lab is a true reflection of his determination, below. ciplines and two universities: the fuel cell chemistry inter ested chemical engineers; the special materials interested ma terials science students; the manufacturability interested me chanical engineers; and the applications interface interested electrical engineers. Through an NSF program, students at Penn State were also involved (in the 1997-98 school year). The students worked in groups, which required the develop ment of communication skills and experience with teamwork. It marked probably the first time these students had been ex posed to peer evaluation. It was also the first time most chemi cal engineering students came in close contact with students in other disciplines, at least at a high, working level. A key driving force that made the project fun was that it required the hands-on" design of a complex system. The chemical engineering and materials science students learned how to make and optimize a single cell, and then the chemical engineering students joined the mechanical engi neering students to make a "s tack, or several single cells connected in electrical series. This task required designing the flow field plates and seals, and dealing with the ever present safety concerns. Along the way students built sev eral versions of fuel cell test stands, ranging from small to large scale. Eric's role as project leader was to integrate all these disci plines and coordinate with faculty in other departments It involved a degree of risk since the outcome wasn't certain at the beginning, but Eric kept a global view and ensured that students learned so mething at each s tage. While the mechani76 ca l engineers were way ahead in building the rolling stock for the train the chemical engineers were learning that it is hard to build a fuel cell. The fuel cells worked, but they didn 't provide enough power. Eric had the foresight to have stu dents each quarter build on what was learned th e previous quarter and improve it. In that way, progress was consistent and the students had a feeling of success in achieving their team goals. As to my imagined fears at the outset, it turn s out there was only one explosion (no injurie s). And for good measure the s tudent s were led through s ubsequent safe ty procedures to see that there was ne ve r another. On top of hi s success in bringing the idea to fruition, Eric a l so learned how to guide such a project and avoid the end of-q u arter rush, which is very important to tho se sc hools still on a 10-week quarter system In evaluating the experience, Eric says, "Students are over-confident and under-experi enced." He note s the biggest problem s were communication (as in the real world) and time management (as in the real world), but he was surprised at what they could do. The course is definitely good preparation for work after school! By 1999 under Eric's steady s teering the little train project had gone from "I think I can, I think I can," to "I know I can, I know I can." FUEL CELL COURSES The classroom program began to blo sso m when Eric asked to teach hi s new fuel cell course on TY. I had been encourag ing faculty to pre se nt more of their specialty courses on TV so that they could be taken by engineers who couldn't come to campus. When Eric committed to giving it a try we had to rearrange the teaching schedule, with so me faculty doubling up to cover his previously assig ned lo ad, but we managed and the course was a great s ucces s. Engineers in fuel cell Chemical Engineering Education

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companies on both coasts took the course on TV, and ap proximately 160 University of Washington students and 85 distance-learning students have taken the course since 1998. It also has been offered as a professional s hort course at three national meetings of the Electrochemical Society With all this experience to bank on Eric was able to part ner with colleague Dan Schwartz and get funding from the Dreyfus Foundation to integrate fuel cells into the chemical engineering curriculum. They put a fuel cell in the unit op erations laboratory and created new courses Eric had already partnered with Chevron, Apple Computer and Boeing to pro vide a high-vacuum device for the undergraduate unit opera .tions laboratory, where the students investigated Knudsen flow in conditions pertinent to the electronics industry. But Eric isn't satisfied with having students make things without also understanding them. Two classes were developed one a course for junior s in science and engineering (and for fuel cell professionals) and the second a more rigorous course for seniors As with all his courses, Eric makes good use of PowerPoint slides that are colorful and appeal to students for later viewing. They also make it possible for Eric s graduate students to teach the class as a distance-learning course (as part of a Huckabay Teach ing Fellowship). Students frequently take the courses because of their de sire to contribute to improving society. They often report that after the course, they appreciate how hard it is to make a fuel cell system work, and they al s o are perceptive in seeing the potential of fuel cells and recognizing that the public doesn t understand where the hydrogen is coming from. Since Eric Sprin g 2006 As evidence of Eric's inner drive, he insists on maintaining his regimen of bicycling to work even in one of the rainiest months in Seattle's history. It takes more than a few rain drops and puddles to steer these wheels off course. attends conferences during the quarter he comes back with real-life examples of fuel cells that demonstrate to the stu dents that these are current topics and not just classroom les sons As one student put it, "They are cool, very modern." Lesson s learned in the Fuel Cell Locomotive Project are applied in the fuel cell courses, too : design projects involve working with professors and other students and developing a fuel cell system that incorporates constraints of size and functionality for real-life situations As the courses proceed from year to year, the projects change to reflect what was learned previously. Since Eric is also now chair of the de partment, he shares the teaching load with Professors Dan Schwartz and Stuart Adler. The fuel cell curriculum has grown to include three faculty members and several courses. At the undergraduate level are Introduction to Fuel Cells, Fuel Cell Engineering and Solid Oxide Fuel Cells. Courses at the gradu ate level are oriented to the scientific questions raised by fuel cells and other reactions on surfaces : Thin Film Science, En gineering, and Technology; Reactions at Solid Surfaces; and Electrons at Surfaces. For Eric, the education program is a big part of his driving force. He says "If we can t work with students, I don't see why we re here. As a result of their experience in fuel cell projects designs and courses, many of our graduates have gone to work for fuel cell companies. Some were apprehensive about inter viewing with such companies, saying, "But our fuel cell didn't work very well." In the course of their interviews they found out that the companies' fuel cells didn t always work well either-and were hired! 77

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REACHING OUT TO GRADUATE STUDENTS Befitting his individualist nature when graduate students start to work in Eric s lab the first assignment he gives them is to watch the film Dr. Stran ge /a v e. It s his habit to advise his students on books to read music to listen to, and movies to see. After broadening the students outlook on research, it's time to get down to work. New students quickly learn Eric's man tra for reading a technical paper is to read from left to right, stop at the end of each line, then see that you understand it before going on to the next one. He has new students read three to four papers, discuss them, and write a research pro posal. This exercise sharp ens their critical thinking skills and illustrates that the generation of new knowl edge requires thought and hard work sponse to particular problems One example of this philosophy in action is how Eric's group was able to resolve a scientific argument. The back ground involves a focus of current research: namely to de termine the reaction mechanisms that occur at surfaces. A major application is direct methanol fuel cell s (DMFC) for portable power and low-power applications. Teasing out the mechanism for the oxidation of Student s then begin working on a problem in his lab possibly using the high-vacuum surface sci A look inside Eric's lab. methanol on platinum and plati num plus ruthenium require s careful work, often under high vacuum. Yet, the understanding is essential if DMFCs are to become widespread Begin ning with the Langmuir Hinshelwood surface reac tions mechanisms are proposed and then experiments designed to determine the rate-controlling steps Some researchers felt the reaction followed a parallel path, while others in s isted it was a serial path. By elucidating four different controlling rates of re action, Eric s group was able to determine that the previous findence equipment. As the work nears the point of publication a draft is submitted, but it comes back covered in red ink. The laboratory holds a copy of Fowler's Modern English Usage and students are expected to use it. Papers from Eric's labo ratory don t have author lists as long as the abstract; you are expected to do the work yourself. As you might expect, some of his graduate students are getting a chemistry degree, and he teaches those students chemical engineering principles too ; he thinks everyone should know them! Eric believes in thorough preparation. His students are prepared for the fu ture by writing and rewriting papers, and by presenting the work at conferences, always with a fundamental look at the problem. As you d expect Eric s Ph.D. students work pre dominately in companies dealing with fuel cells electrochem istry, and surface science (see Table I). LAUNCHING A LAB Sometimes a researcher will look around for a problem that can be solved with techniques and instruments he/she has available. Not Eric. He sees a problem and thinks how best to solve it, then proceeds It was in this fashion that he built up his laboratory equipment to be the extensive lab that it is today (see Table 2). The philosophy does require creativity, though since it often means learning a new area that one hasn't formally s tudied. Thus, the effects of high electric fields, ceramics (and solid oxide fuel cells) and linear density functional theory were things he learned in re78 ing s in favor of the series path were the result of reaction conditions and catalyst modifiers (e g. ruthenium ) Both sets of reactions are necessary but local conditions determine which ones apply in any given situation. Since fuel cell s operate at temperatures above room tem perature Eric conducts studies at higher temperatures too. More recently work on s olid-oxide-supported platinum cata lysts support s the goal of fuel cell s that run on die s el or other hydrocarbon fuels without having to reform the fuel to pro duce hydrogen. Copper-ceria electrocatalyst s minimize car bon formation thus avoiding the problems of nickel-based electrocatalysts Solid oxide fuel cells have s trong potential for use in transportation defense and indu s trial and residen tial applications. The fundamentals of surface science have widespread ap plication in other fields, too. The power of fundamentals was brought home to me one day when I was reading a paper about how polymers slip while being extruded but the phe nomena s eemed to depend upon the type of surface. I asked Eric about that, and described some of the surfaces mentioned briefly in the paper. He proceeded to line them up for me explaining which one s would allow slip at the lowest pre s sure drop etc. Impres s ed I called the author (at an industrial laboratory); the paper had not been completely forthcoming but the author confirmed that the sequence Eric provided was exactly what was found in the laboratory. C h e mi ca l En g in ee rin g Edu c ati o n

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ERIC AS CHAIR Eric was appointed acting chair of chemical engineering in 1999 and soon became the permanent chair. One of the high lights of his chairmanship has been the preparation and ex ecution of the department 's Centennial a celebration of the beginning of the department in 1904. It involved hundreds of people to organize, and Eric seems to have tapped into his student experience as an actor and techie to pull off the pag eantry to the last detail. With Eric in the driver 's seat, the event was carefully crafted to show off the department to alumni, the university, and ourselves. He reports he had the usual "opening night" jitters but all the planning made for a memorable event. In the end, even his planning for contin gencies got tested, as a thunderstorm erupted just as we were about to leave the luncheon to walk to the laboratorie s Eric enjoys hearing stories from retired alumni and values their friendships. In turn alumni have been very generous to the department and Eric loves the stories they tell about chemical engineering in the "e arly days." Chuck Matthaei (of Roman Meal Bread) has shown great interest in educa tion and recently endowed a professorship. Neil Duffie (of Willamette Industries) knows what i s important and chal lenges Eric to think strategically; Neil has been a longtime supporter of graduate fellowships. PERSONAL CHARAC T ERISTICS I have always valued Eric 's creative side. If there is an idea to explore "outside the box, Eric is one of the people I want in the group. In addition to his comprehensive knowledge his willingness to forge his own path means he has a knack of looking at problems in different sometimes quirky ways, and this spawns new ideas. Eric is not all fuel cells and surface reactions though. Well known for his love of Gary Larson's Far Side cartoons, he has an endearing sense of humor that can defuse tense situa tions. His love of music is also well known: He and his wife Monika attend the opening night of Seattle Opera every year. Eric even drew upon his theatrical side at the departmental TA B LE 1 Stuve's Ph.D. Grad u ates holiday party in December 2005, when he serenaded the at tendees by singing "O Tannenbaum." Further evidence of his well-developed nonscientific side i s his practiced penmanship: Eric 's mother was artistic, and Eric learned calligraphy-so well, in fact, that his wife re quires a card done in the elegant writing sty l e for birthdays and special events The artistic streak carries over to Monika, as well, who has achieved teacher status in Ikebana flower arranging. She quickly learned the Japanese art and has even displayed her accomplishments at a Seattle show along with a Japanese master and his entourage. The Stuves also enjoy traveling, and one benefit of Eric 's fuel cell research has been an increase in opportunities to do so. A repeat destination is Bangkok Thailand as part of an exchange program Eric participates in with Dow Chemical and the Chemical Technology Department of Chulalongkom University. During their last visit, they encountered a situa tion we all hope to avoid. As the plane took off from Bangkok, a bird flew into an engine and the pilot aborted the takeoff. In the process, a wheel caught fire, and the plane was evacuated at the end of the runway. While the plane was quickly empty ing, Eric was concerned about his wife and son Kurt who were also onboard. As if sliding down the chute weren t enough excitement, it took some time for the family to re unite. Then, more problems appeared. Since everyone had left their carry-on baggage on the plane, no one had their pa ss port. Thus, they could not enter Thailand again while waiting for another plane the next day! Eventually, sanity occurred among the authorities and the passengers were taken to a nearby hotel to spend the night. The next day the plane took off without incident, and Eric and his fami l y returned to Seattle safe and so und and none the worse for wear. Leave it to Eric to take such an unplanned pit stop" in stride. CONCLUSION With his commitment to keeping students on the right track and his fundamental approach to problems, you might say Eric is the kind of chemical engineering educator who he l ps set the pace for our profe ss ion. Not bad for an Indy fan. 0 TABLE2 Eq u ipment in St u ve's Labo r atory Naushad Kizhakevariam Varian in Portland Rod Borup Lo s Alamos National Laboratories David Sauer Intel Diff e r e ntial Electrochemical Mass Sp ectro meter Ultra-high vacuum (U HV ) analysis chamber (4) Pot e ntial s tep chronoamerometry Thom as Jarvi UTC Fu e l Cells Timoth y Pink e rt on Int e l Dawn Scovell Int e l Suresh Sriramulu Tiax Consulting (fo rmerl y Arthur D Little) Seng-Woon (David) Lim UW Chemistry Dept. Thomas H. Madden United Technologies Re sea rch Center Chris Rothfuss U.S D e partment of State Nallakkan Arvindan Symyx Corp. Spring 2006 Linear and nonlinear electroche mical impedance spec tro scopy (EIS and NLETS) Field Ionization/Emission Microscopy ( FTM/FEM ) X-ray phot oe l ec tron s pectro scopy (XPS or ESCA) Low energy e l ec tron diffraction (LEED) Thermal desorption spec tro scopy (T DS ) Time-of-flight ma ss s pectrom e t e r ( TOF-MS ) Auger electron spectroscopy (AE S ) Contact potential difference (CPD) Electron s timulated desorption ion angular distribution (ESDIAD) 79

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.ta ... 5.4...._ d e ..:..p_a_r_t_m_e_n_t _______ ) Some exhausted members of the Tulane University Uptown recovery team on Sept. 15, 2005-two weeks after Hurricane Katrina. Left to right: Greg Potter (chemistry Washington Univ.), James Peel (Bruker Instruments) Russell Schmehl (chemistry) David Mullin (cell and molecular biology) Scott Gra ys on (chemistry), Qi Zhao (chemistry), Gary McPherson (chemistry) W Godbey (CBE), Brian Mitchell (CBE) Vijay John (CBE), and Bob Garry (microbiology). From Survival to Renewal Katrina and its Aftermath at Tulane's Chemical and B iomolecular Engineering Department BRIANS. MITCHELL, JOHN A. PRINDLE, HENRY S. ASHBAUGH, AND VIJAY T. JOHN Tulan e University New Orl eans, LA 70 11 8 T h e Chemical and Biomolecular Engineering Depart ment at Tulane University ha s a rich tradition d at ing back to 1894 as the first established program in chemi cal engineering in the South and the third program in the coun try.111 Tulane University faced a s truggl e for s urvival in the fall of 2005 when the city of New Orlean s was devastated in the wake of the flooding from Hurricane Katrina. This article chronicles the experiences of the department and its efforts not just to maintain viability but also to look to the future with a renewed se nse of purpose. In keeping with the university 's approach to describing the events of the period between Aug. 29, 2005, and the pr ese nt the article i s divided into three sec tion s: s urvival recovery and renew a l. As background, we give the re a der an idea of the depart ment. At the tim e of Katrina ther e were nine full-time fac ulty ( Professors O'Connor, Papadopou l os, Law, Mitchell, Ashbaugh, Godbey, Lu, De Kee, and John) two s taff mem bers (Dr. Prindle who serves as a se nior instructor and labo ratory s upervisor and Ms. Lacoste the departmental admin istrative sec retar y), and Professor Emeritus Gonzalez who Copyrigh t C hE Division of AS EE 2006 80 Che mi c al Engineeri11g Ed u ca ti o n

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participate s in teachin g gra du a t e courses and in collabora tive research. The departm e nt had a bout 30 gra duate s tudent s studying toward their Ph D ., and about five part-time M.S. students. Undergraduate enrollment was about 80 with gradu ating classes between 15 and 20 s tudent s Undergraduate in terest in the program, and enrollment number s along with it saw a s teady increase as a re s ult of the r ece nt emphasis and inclusion of biomolecular engineering into the curricu lum in 2003. SURVIVAL Residents in the New Orlean s area are accustomed to threat s from hurricanes but there had b ee n none to hit the city si nc e Betsy in 1965. The horrendou s traffic jam s and inconve niences of evacuation that were experienced when Hurricanes Georges and Ivan came close but mis se d the c ity convinced many that evacuation was unnece ssary A sense of complacency had set in. But to colleagues in the chemical engineering community with his reque s t for help in placing our s tudent s (see box on page 82 for hi s personal recollections ). Vijay John followed up with a se parate e-mail. The department will forever be grate ful for the outpouring of help for our s tudents and faculty. The major ChE departments geographically closest to Tulane-in Houston and in Baton Roug e (Rice, the Univer s it y of Houston and LSU ) took in many of our students and offered our faculty laboratory and office s pace-we are so tremendously thankful. Katrina wrought significant damage to Tulane. Two-thirds of our picturesque campus in the hi s toric Uptown neighbor hood of New Orlean s had flooded Winds from Katrina dam aged the roofs of severa l buildings The computer systems were down with the university backup tapes located safe ly ye t inaccessibly in high-rise buildings downtown near the Superdome, the si te of so much trauma and sadness. The upper administration was op Katrina was no mere threat. By Aug. 25, it was clear the storm was zeroing in on the New Orleans area Some 300 miles off shore, the hurricane s trengthened to a Cat egory 5 status, giving sufficient rea so n for the university to initiate evacuation plan s for students. Ironically enough, the week end of Aug 27 was s upposed to be th e faculty's annual welcoming of the late s t batch of freshmen, but ha s ty departure s were being urged instead. President Scott Cowe n called a meeting of all students and requested that they all return home or evacuate to Jackson on buse s the univer sity had arranged. Temporary hou s ing had also been arranged for evacuating s tudent s at Jackson State University Our faculty made individual plans for the storm while making sure their graduate s tudents had It was particularl y heartwarming to see the graduate students back and helping us clean the laboratories to erating from Tulane' s Executive Business School campus in Houston-the saga of how they brought back function to opera tions and coordinated the recovery is an interesting story in itself (see ). The breakdown in payroll systems was the first major crisis, since the university had no idea how to is sue paychecks or even a way to identify tho se on its payroll. We were dealing with emergency financial personnel who had to be educated that a graduate stipend simply meant sa lary. With the help of the deans, department chairs, and faculty members, all employees and graduate students were identified and paychecks issued through direct deposit. Professor Dan De Kee who also serves as the associate dean for gradure s ume research acti vi ties. E v en thou g h s ome had damaged apart ments the y teamed up and those w ith li v able apartments opened their doors and hearts to those without. concrete evacuation plans Two of our faculty decided not to evacuate prior to Katrina but the conse quent flooding and the infrastructure and sec urity issues in the city mandated they leave a few days after the hurricane. Most faculty and students first evacuated toward the Baton Rouge Hou s ton and Jackson areas. The events of Hurricane Katrina have been well docu mented. We all watched the disaster in real time with acute sadness, for we could clearly identify with all the locations in the images. The stress was heightened by the fact that phones were not working and we were unable to get in touch with our colleagues and students. Tulane 's information tech nology services were disrupted and university e-mail ad dresses were useless. Communication was slowly established through text-messaging and the use of temporary e-mail ad dresses. It was at this time that Hank Ashbaugh got through Spring 2006 ate studies, was invaluable as he kept the pressure on payroll administration from his evacuation location of Gaithersburg Md In many instances, the university simply took the word of the deans that indi viduals belonged on the payroll and issued paychecks. It is to the credit of the university that all employees and graduate s tudent s were paid during the entirety of the period be tween Sept. 1 and Dec. 31 2005, while the university re mained closed. Within a couple of weeks following Katrina, faculty mem bers Brian Mitchell and Vijay John-who live to the north and to the west of the city-had returned to their homes, grate ful to find minimal damage John Prindle, who lives near Baton Rouge and had not evacuated, served as a communi cations conduit (see his personal account in box on page 83). Hank Ashbaugh slowly traveled from Jacksonville, Fla. up the eastern seaboard to Troy, N. Y. (Ren sse laer) where he even8 /

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82 Professor Hank Ashba u gh s recollec t ions o f connecting w it h hi s rese a rch group and the chemical eng i neering community Aft e r Hurri ca n e Katrin a hi t o n A u g. 29, 20 05, a se n se o f h e lpl e s s n ess g r ew in m e as I w at c h e d th e p e rp e tual cove r age o f th e fl oo din g of New Orl e an s fro m m y fath e r 's h o u se in Ja c k so n v ill e Fla Th e s t o rm had kn oc k e d o ut th e ph o n e n etwo rk f o r a n yo n e w i t h a New Orl ea n s ar ea co d e so co mmuni c ati o n s w ith th e f a c ul ty in m y d e part m e nt we r e s p o t ty a t b es t F o r e m os t o n m y mind was w h ere m y r esea r c h g r o up h a d sca tt e r e d in th e wa k e of K a trina. I qui c kl y l oc at e d o n e p os t doc w h o s till ha d a New Y o rk a r ea code o n hi s ce ll ph o n e a nd l ea rn e d th a t h e' d s af e l y ev a c u a t e d wi th P ro f esso r Yunf e n g Lu s gro up t o Shr eve p o rt l a. M o r e wo rri so m e we r e th e two g radu a t e s tud e nt s fr o m Indi a w h o had ju s t arri ve d in th e U n i t e d Stat es to j o in m y g roup th e w ee k b efore th e s t o rm H ow d o yo u lo c at e tw o n ewco m e r s t o th is co unt ry w h o h a d sca tt ere d in a pani c? Th e n I re m e mb e r e d th a t I h a d r ec ruit e d th ese two s tud e nt s fr o m UICT wi th th e h e lp o f Professo r V.G. Pangarkar. I e -m a il ed him a t 11 p m. a nd b y 2 a. m m y tw o s tud e nt s h a d co nt ac t e d m e t o say th ey were sa f e l y o n th e ir way t o T exas M y s u ccess i n l oca tin g my f a r-flun g g r ou p gave m e th e id e a that we s h o uld u y t o r eco nstitut e th e d e p a rtm e nt ove r th e Int e rn e t. Th e fir s t s t e p was t o l oca t e t h e individu a l fa c ul ty m e mb e r s. Th e Int e rn e t se r ve r s f o r Tul a n e had b ee n s hut d o wn b e f o r e th e s t o rm so u s in g c ampus e -m a il a dr es s es was o ut In s t ea d o n S e p t 1 I wro t e a n o p e n e mail t o th e c h e mi c al e n g in ee rin g co mmuni ty-<:o p y in g eve r y dep a rtm e nt c h a i r -t o t e ll o ur s t ory and r e qu es t th e wh e r e ab o ut s o f a n y Tul a n e f acu l ty Th e r es p o n se wa s ph e n o m e nal O ve r th e co ur se o f th e n ex t thr ee d ays I r e s p o nd e d t o ove r 400 e -mail s w i s hin g u s we ll vo lunt ee in g supp o rt and m o r e imp o rt a ntl y, g i v in g m e cl u es a s t o wh e r e o u r f ac ul ty had evac u a t e d Within a wee k a nd a half I man age d t o l oc at e a ll o urf acu l ty, ge t a lt er n a t e co ta c t inf o rmati o n f o r eac h a n d b eg in t o r e a sse mbl e th e d e partm e nt. T wo wee k s aft e r th e s t o rm I se nt a seco nd e m a il t o th e ChE co mmuni ty pr ov idin g n ews o f o wf ac ul ty s w h e r ea b o u ts As f ac ul ty me mb e r s were b e in g l oc at e d w e start e d t o co mpil e li s t s of gra du a t e a nd und erg radu a t e s tud e nt s t o e x p a nd o ur "v irt ual" d e partm e n t. Us in g th e co nta c t s we had d eve l o p ed ou t s id e th e d e p a rtm e nt we we r e a bl e to co nn ec t s tud e nt s w ith de partm e nt s a nd uni ve r s iti es t hat h a d vo lunt ee r ed to h os t th e m durin g o ur se m es t e r in ex il e. T o f ac ilit a t e int e rd e p a rtm e ntal co mmu ni c ati o n s we crea t e d a bl og ( ) t o dis se min a t e inf or m a ti o n o n s upp o rt f o r s tud e nt s, s tud e nt i eg istr a ti o n c o m m uni ca ti o n s fr o m o ur c h a ir a nd mi sce llan eo u s tidbits M o r eove r th e bl og p ro vid e d a w ind ow f o r o w f ri e nd s o ut s id e th e d e p a rtm e nt t o k ee p updat e d o n o ur s t a tu s. tually spent the rest of the s e me s ter Durin g hi s travel s h e stopped in at universitie s along the wa y ( North Carolina Dela ware Princeton ) where he had s tudied. Kyriako s Papadopoulo s also evacuat e d to N e w York ( Columbia ) a ft e r a two-week s ta y in Lafa y ette L a. W Godb ey e nd e d up in Hou s ton ( Rice ) b y way of Huntington W.V a D a ll as, T exas Grapevine Texa s, and Fort Smith Ark. Kim O Connor w e nt to Houston ( Baylor Medical School ); Yunf e n g Lu to Albu querque ( Univer s ity of New Mexico ) b y wa y o f Hou s ton ; Richard Gonzalez to Jackson Miss. ; and M s. Laco s te to r e l a ti v e s who live north of the cit y Victor Law went to An g leton Texa s and had to e v a cuate a seco nd tim e du e to Hurri c an e Rita. Our s tudent s w e r e sc att e red all o ve r th e c o untr y and w e re welcomed in a t a ll univ e r s iti es W e had s urvi ve d th e hurri c ane. The n ex t s t e p w as to plan our r ec ov e ry. RECOVERY The early day s following the hurricane wh e n th e campu s and s urroundin g Uptown neighborhood were without elec trica l power are detailed in Brian Mitch e ll 's account of th e recovery effort s (s e e box on pa g e 85 ). The univ e r s ity hir e d Belfor an international dis as t e r-recov e r y corporation a nd th e campu s wa s te e min g with B e lfor employ ees. Hu g e pow e r generator s and trailers were scatter e d acro ss campu s a s B e lfor set about drainin g water from buildin g ba s ement s ( not e : b ase ments in New Orlean s = bad idea! ), g utting dama g ed floor s, and reinstalling utilitie s By early to mid-Octob e r e lectrical power had been restored to the neighborhood a nd mo s t of th e campus had power with th e notable e x ception o f the s ci e n ce building where electrical transformers and oth e r utiliti es placed in the bas e ment had been de s tro ye d. Th e univ e r s ity 's s enior administration had return e d to the cit y a nd had s t a rted operation s in the main admini s tration buildin g ( Gib s on H a ll ). From there they monitor e d the recover y and b eg an th e s trat egy for renewal. From the department 's per s pective thi s wa s a tim e to tak e stock of our lo s se s Brian Mitchell Vijay John and John Prindle w e r e among a handful of facult y a nd s taff cleared for re g ular entr y into th e en g ineerin g buildin g All oth e r e mplo y e e s had to g et clearan ce to e nt e r the buildin g ( u s uall y b y ca ll in g Brian or Nick Altiero th e dean ) and w e r e esc ort e d int o the engineering buildin g b y Brian to r e co ve r c omput e r hard drive s, etc Ther e w e re s ignificant s afet y i ss u es, a s th e build ing ventilation sys tem s had not y et be e n de c ont a min a t e d During the month s of October and November th e comput e r and communication s y s tem s at Tulan e returned to norm a l operation and we s lowly tran s itioned b a ck to our univ e r s it y e-mail addre ss e s It wa s an inter es tin g tim e, as Bri a n John a nd Vija y c ame in a lmo s t ever y da y to man the phone s, k ee ing in touch with our collea g ues and our stud e nt s. W e h a d to balance these dutie s with our p e r s onal liv es in whi c h Katrina had impacted s chool openings for our childr e n job condi tions for our spouses and much more Th e r e wa s v e ry littl e C h em i c a l E n gin e e r in g Ed u c a ti o n

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under professional supervision. time for intellectual work. It was a time in which we a ll real ized the frailty of the human condition and l earned to act with newfound compass ion. Thre e of our co lleague s had s uf fered s uch damage to their home s that they needed tempo rary hou s ing Overall at Tulane, 2540 per ce nt of the emp lo ees had hom es significantly dam age d b y flooding. There was and contin u es to be a re s ounding s pirit of helping one another We learned seve ral le ss on s from our ex perience s in s ur vival and recovery that are u sefu l to pa ss on. When planning for disaster s, science and engineering d e partment s should al ways take into account the conseq u ences of electrical pow e r B y ea rl y December mo s t buildin gs were functional and the campus was being s pruced up for the return of the s tu dent s Faculty member s throughout th e university were ex cited abo ut returning to work. Pre s ident Cowen and the up per administration had done a wonderful job in maintaining s tudent morale by pre se nting Tulane as a unique institution where rigorou s education would b e combined with exce tional opportunities to participate in public serv ice to rebuild a great city. Early r egistration rat es were high and the facu lt y was looking forward to the future. We knew that the univerand communication failures for ex tended periods It i s wise to maintain ex tra s uppli es of liquid nitrogen to preserve bio l ogica l samp l es. Personnel and g raduate s tudents s hould ha ve alternative e-mails that can be accessed anywhere through the Internet. Inventories of chemicals, in s trument s, and ge neral propert y mu s t b e maintain e d by the department. Access to buildings und er re pair s hould be tightl y con trolled even to emp lo yees-a faculty member paying a no s talgic visit to the medical sc hool building before th e power had been restored i s sa id to have caused s ignificant water damage b y using th e plumbing while the s ystem was under repair. Even if thawed biologicals (e.g., tissue samp le s) h ave been removed decontamination of the entire building mu s t be performed W Godbey contemplates the whoosh of liquid nitrogen vapors that indicated his dewar full of biological samples was still cold-evidence that years of research were still safe. Dr. John Prindle s recollections of maintaining connections with the undergraduates Students are any c h emica l engineer in g department 's lif eb l ood. Th ey c hall enge the faculty t o co ntinuall y improve t eac hin g sk ills Th e ir tuition pa y s for a porti o n of th e departm ent's expenses. And with eac h freshmen class co m es a distinctive v i ew of the wo rld and how to improve it. In man y ways, students are a d e partm e nt's prima ry l egacy. So, it i s not surprising that a s tron g pers o nal connection forms betw een fa c ul ty members and eac h s tudent they instru c t. In th e aftermath of Hurri ca n e Katrina this p ersona l co nn ec ti o n was severely tested. F o r more than a month after th e even t the uni ve rsi ty's n etwork se r vers we r e down, rendering the familiar student e -mail addresses useless Shortly after Tulan e an n ounced it was ca n ce lin g th e fall semeste ~ s tud ents began ca llin g faculty at home t o discuss their o pti ons. Student conce rn s ranged from whet h er the y s h ou ld a tt end another university for the semester to w h e th er they should register for c h emica l engineering co ursework at that university. Durin g these discussions, the facu l ty realized most s tud ents sim pl y wante d to b e r eass ured that we wou ld assist them any way we cou ld With eac h ca ll s tud e nts we r e See Maintaining Connections with Undergraduates, --------------------------------co ntinu e d o n page 98 Sp rin g 2006 83

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Members of the faculty and instructional stuff in less stressful times. From left, standing: WT. Godbey, Daniel De Kee Vijuy John, Yunfeng Lu, Kim O'Connor Kyriukos Papadopoulos Brian Mitchell, and John Prindle. Seated: Richard Gonzalez, Hunk Ashbaugh, Victor Law. s ity as with all employers in th e New Orleans region, would be in a difficult financial situation. But there was a conta gious spirit to get the students back work hard build up re searc h and try to recover It was particularl y heartwarming to see the graduate students back and helping us clean the laboratories to resume research activities. Even though some had damaged apartments, they teamed up and those with liv able apartments opened their doors and hearts to those with out. Yunfeng Lu who lives a block from campus, feverishly worked to repair his damaged home so his sizable group of gra duate s tudents could h ave a place to s tay if they were un a ble to find appropriate accommodations. RENEWAL On Dec. 8, the Board of Administrators at Tulane Univer sity announced a renewal plan as a consequence of the finan cia l exigency. The plan has turned out to be the largest re st ructuring of an American institution of higher education on r eco rd. Under the plan some 230 faculty members were ter minated, including 35 member s of the School of Engineer ing. The Departments of Civil and Environmental Engineer ing, Mechanical Engineering, Electrical Engineering, and Computer Science have been slated for elimination by the fall of 2007. The university has been reorganized with the formation of a School of Liberal Arts and a School of Sci ence and Engineering, in addition to the professional schools, to fully constitute a comprehensive university. Chemical and 8 4 Biomolecul ar Engineering is one of only t wo s urvi vi ng engi neering departm en ts ; Biomedical Engineering is the other. Both were m e rged into the School of Science and Engineer ing which ha s been further divided into academic divisions. Biomedical Engineering is now part of the Division of Bio logical Science s and Engineering. Chemical and Biomolecu lar Engineering and the Department of Chemistry form the Divi s ion of Chemical Science and Engineering. The entire renewal plan make s for fascinating reading for those inter ested in academic organization strategy, and administration. It can be found at < http://renewal.tulane.edu/ > Long-term goals of the plan as state d b y the Board of Administrators are: (1) diligence in retaining our institutional quality and working to heighten that quality ; (2) dedication to providing an unparalleled holistic undergraduate experience for our students; (3) continued strengthening of core research areas and graduate programs that build on our s trength s and can achieve world-class exce llenc e; and (4) a n absol ute commit ment to using the le ssons learned from Katrina to help re build the city of New Orleans and to then extend those les sons to other communities We mourn the breakup of the School of Engineering, an institution that existed for over a century. We also mourn the departure of our colleagues who have worked tirelessly to improve the sc hool. It is sufficient to say that we will con tinue to work hard toward enhancing the reputation of the department. The current dean of the engineering school, Nick Chemical Eng i neering Education

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Altiero, ha s b ee n a ppoint e d the n ew dean of the School of Science and Engineerin g W e believ e hi s appointment indi cates the univer s it y's recognition that e ngineering is st ill a significant and continuing component of Tulan e, and we look forward to working with him to renew recon s titute and ex pand engineering as opportunitie s pre se nt them se l ves. He ha s be e n clearl y told that th e Board of Administrators will be receptive to new idea s for engineering at Tulan e upon return to financial s tabilit y What i s the futur e of th e department ? Th e univ ers it y is ex pected to return to financial s tabilit y within a couple of years, with the bond mark e t expressing co nfidence in the s trong management team at Tulane .12 1 Our s tud e nt body ha s r e turned and we are back to high inten s it y in both rese a rch and e duca tion. Our informal merger with chemistry i s a sea mle ss fit. O ver the years, the two departm e nt s h ave formed stro n g bond s, with re sea rch collaborations and an e n viro nment of mutual s upport. The atmosphere of cooperation ha s l e d to th e establishment of superb instrumentation fac ilitie s in ad vanced s pectro sco p y, electron micro sco p y, and organic a nd inor g anic analy s i s. We are especially proud of our high-r eso lution electron micro sco py and confocal micro sc op y facili tie s wherein we are in s tituting a full range of c ryoima gi ng techniques for biological imagin g Collaboration s with the Medica l School have been se t up a nd we are considered a vital pla ye r in Tul a n e's objective to b eco m e wo rld-cl ass in health sc ience s r esearc h Such collaborations a r e in s tem -ce ll culture gene delivery to cancer ce ll s, and vacc ine de ve lop m e nt and delivery technologie s The department ha s s i g nifi cant s trength s in the areas of computational chemistry, se lf assembly, nano s tructured material s, colloid sc ience and poly mer and ceramics processing The university ha s clearl y s tated its intent to bring every Ph D.-grantin g department up to na tional prominence, and we ex pe c t s i g nificant inve s tm e nt s to our department a s the univer s ity return s to financial viability. The next couple of years will be difficult. In addition to their intellectu a l live s, faculty and s tudents will worry a bout r e buildin g their p e r so nal liv es which mu s t come fir s t. Kind n ess a nd compassion will b e th e order of the day in the de p a rtment in d ea lin g w ith s uch i ss ue s. It will also be terribly exc iting to witness and participate in the rebuilding of the city. It i s incredibly heartening to s ee students mobilizing on a ll kind s of public serv ice project s, from involvement in public sc hool education, to g utting de s troyed hou ses so that resi d e nt s can r e turn to rebuild and establish communities, to pro v iding m ea l s to th e thou sa nd s of laborer s who are working to r e build the c it y We a re det e rmined to per seve re. Plea se wish u s well ... and come v i s it. ACKNOWLEDGMENTS WT. Godbe y made very helpful suggestions to the article. The faculty s taff and st ud e nt s of the Department of Chemi ca l and Biomolecular Engineering express our deepe s t grati tude to our colleagues in the chemical engineering commu nit y for th e ir man y ges ture s of kindness in the wake of Hur ricane K at rina and for their numerou s forms of support in helping u s to re-attain our pre s torm leve l of excellence Department chair's note: I am privileged to work with my faculty and s taff colleagues who s howed so much courage and dedication to re s toring the department to viability. The three coauthors of thi s article ( Prindle Ashbaugh, and Mitchell) were especially helpful wi th th e ir e ffort s to co ntact every under gra duat e and graduate s tudent and their e fforts to re s tore th e r ese arch infra s tructure. They were always avail able to help and Profe sso r Mitchell coordinated the e ntire re covery aspects of the engineering sc hool. To reb u ild the depart ment with s uch colleague s is the best job I could hope for. REFERENCES I. Westwater J.W., The Beginnings of Chemical Engineering in th e USA ," Ad v Ch e m S e r 190 141 ( 1 980) 2 Chr o ni c l e o f H i g h e r Edu c aiion Jan. 27 (2006) 3. Walz J Y. Ch e m En g. Ed. 246 Fall (1995 ) 0 Professor Brian Mitchell's narrative on the recovery of our physical facilities T wo weeks after Hurri cane K a trina the department s personnel situat i on was st ill cr iti ca l but much m ore stable. All facu l ty and staff had b een l ocated and we r e in co mmuni cat i on, most undergraduates had b ee n a dvis ed which co urs es to tak e at th e ir host institutions, and grad u at e students we r e in contact with their advisors. While many cont inu e d to strugg le w ith personal issues related to assessment of their home damage FEMA, the R ed Cross, in surance, ac c ommoda ti ons, an d inf o rmin g friends and family of their w h e r eabou t s, it became clear that it was time to give some attention to th e s tatus of departmental facilities, especia ll y th ose related to research. The concern fo r research facilities was uniform th ro u g out Tulan e s research community but the urgency in eng in ee rin g was assoc iat ed primarily wit h biological samp l es that had now b een in unreplenished liquid nit rogen ( L N 2 )-coo l ed dewars fo r two weeks in the swe lt e rin g New Orl eans s umm er h ea t Laura Levy senior vice president for research aut h or i z ed a convoy for Sept. 15 to the Tulan e cam puses t o assess damage. The convoy, l ed by John Clements professor and chair of microbiology and immunology, departed ea rl y that Thursday morning from the Tulane University R eg i ona l Primat e Center in Coving t on, which i s l ocated o n the No rth shore Sprin g 2006 See Recovery of Physical Facilities continued on page 86 85

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Recovery of Physical Facilities Continued from page 85 of Lake P ontchartrain and had not re ce ived any signif i c ant damage from the storm. The eight-vehicle co nvo y co nsisted of resear c hers from both Uptown (Engineer in g and Scienc e) and Downtown (Medical School) ca mpuses and traversed the 24-mile lake Pont c hartrain Caus ew ay bridge in record setting time with the assistance of a poli ce escort. It s entrance into the c ity marked for man y of the r ecove r y -team members their first views of Metairie and New Orleans since the hur ricane. The sights, sounds, and smells did not bode we ll for finding facilities intact. Upon arriving at the Uptown ca mpus, th e Downtown team continued on to th e more Pr ofessor Kim O'Connor s samples in an adjacent labora tor y. The team then co ll ected biologi ca l samp l es from dew ars in the Biomedical Engineering Department conso lidat ed the samp l es into one 25 l dewar with whee l s, and placed the dewar b y a service elevator to facilitate future refilling op erations Some thou g ht was given to ca rr y ing th e portable dewar down the stairs and placing it on the first floor since there was no pow e r in the building but there were indica tions that power to the elevators cou ld be restored on a tem porary basis, if necessary Unfortunately, biological samples that had been frozen in a refrigerator freezer were no l onger co ld and had begun to decompose. DNA samples that had been placed in a freezer to slow decomposition could with stand room temperatures for moderate time periods so they were still salvageab l e and were therefor e re trieved heavily damaged Medical S c hool campus, wh il e the representatives from Scienc e and Engineering set to work. The team from the Chemical and Biomolecular Engine e ring Department co nsisted of Professor and Chair Vijay T. J ohn, Assistant Professor W T. Godbey, and Professor Brian S. Mit c hell. Flashlights in hand the team entered the Lindy Claiborne Boggs Center for Energy and Bi otechno l ogy around 9 a.m. and trudged up the back stairs to the third and fourth floors that comprise the bulk of th e department's research facilities As doors were opened and each lab inspected, hope grew that the department had evaded major damage. Lab benches looked as if students had simply left for lunch. Similar operations related to the co llection and consolidation of biological samples were conducted in the chemistry and biochemistry departments, as we ll as at the Downt own cam pus For examp l e, a recent Publi c Broad c ast ing NOVA segment documents the heroi c efforts of Tulane resear c h e r Tyler Curiel to save irre pla ce able sinonasal undiff e rentiated c arcinoma (SNUC) samp l es from his lab oratory (). LN 2 is also c riti c al to the operation of some advanced analytical tools such as Nuclear Magnetic R esonance Spectrometers An initial scan of the department showed it to be in relatively good condition: no blown-out windows, no water damage and no indications of unauthori ze d entry, save for one broken int e rior window in the department's Electronic Classroom A keypad on the door and no missing equipment in the classroom soon l ed to the co nclusion that security personne l had broken the g la ss sim ply to gain entry and eva luat e damage As doors were opened and each lab inspected, hope grew that the department had evaded major damage lab ben c hes looked as if students had simply left for lunch. Only one lab had minor damage, the result of a window being l eft partiall y open and the hurri cane-force winds toppling some g la sswa r e. The team then concentrated its efforts on two genera l ar eas: securing biological samples and recovering research data. W Godbey was elated to find that his lN 2 dewar full of biological samp l es--i,ncluding rare cells and tissue specimens that were co lle c ted over ye ars of res e ar c h--was still co ld (One can equate his joy at seeing th e co ld white cloud rise from his liquid nitrogen storage free ze r w ith the emotions exhibited by JPL engineers when a probe successfu ll y land s on Mars .) H e quickly r ep l enished the dewar with LN 2 from a pre-Katrina storage tank in his lab and did the same with 86 (NMRs). Gary McPherson and Ru ssell Schmehl our co ll eagues from chemistry dili gently worked to e nsure that the NMR ma g nets in both the Department of Chemistry and Tulan e's Coo rdi nated I nstrumentation Facility (C IF ) did not quen c h. Even tually these units also required that their liquid helium res ervoirs be re charged, a task which invo l ved severa l other dedicated individuals from both chem i stry and CIF The recovery of res e ar c h data co nsi s ted primaril y of re tr i ev ing l aboratory notebooks and co mputers from investi gators' off i ces and labs. It was unknown at that point how l ong the university wou ld r emain closed, and some investi gators had not d ec id e d whether to rel oc ate to other universi ties for the semester. Many opted to leav e their computers for the time being. As it turned out, Tulan e wou ld be closed for the entire semeste1; and many faculty members did indeed relocate to continue their research if on l y out of their homes. As a result man y co mputers and hard dri ves were retrieved durin g subsequent recover y trips The retrieval and shipping of co mput e rs for faculty, staff, and graduate students proved to b e problemati c. Some requested on l y hard drives, wh i c h required opening co mputers, and some requested not on l y co mputers but monitors and other peripherals as we ll Ship ment of lar ge piec es of equipment required tra ve l to neighChemical En g in ee rin g Edu c ari o n

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TA B LE 1 Some Lessons Learned For brief power int e rruption s, a chest freezer is preferable to an upright freezer for storage of biologicals at -80 because it w ill remain co ld for longer periods of tim e. If s p ace an d fund s permit, s t ore biological sa mpl es in LN 2 rather than a fr eeze r becau se a full LN 2 dewar wi ll s tay co ld for months even in 100 F heat i f unopened ; however ... Bio l ogical th e s t orage of ti ssue sa mples with bacterial sa mple s creates a pot e ntial co nt amina ti on i ss ue, so ... Materia l s tran sform bacteria and l yop hili ze th e modified culture broths wi th bacteria in them fo r storage a t room temperature for ind e finit e periods of time Keep a n adequate s uppl y of LN 2 on hand. Consolidate LN 2 samp le s int o one conta in er w h e n ever amenable even if that mean s s harin g one between l abora torie s, s ubject to the co n stra int s de scr ib ed a b ove. B ack up yo ur electronic dat a on a regular ba s is to an eas il y retrievable lo ca tion. Resea r c h Consider repl ac in g your de s ktop computer wi th a l aptop a nd docking stat i o n so data i s easily portable in an eme rgen cy. Data Ha ve st udent s store research notes, laboratory notebooks, and s amples in a predefined location so cri ti cal nonelectroni c data ca n be easi l y l oca ted in their absence Stor e flammable research n o t ebooks in a fireproof a nd wa t erproof container. Pl ace a ll e lectri ca l devices on appropriate l y sized battery backup s wi th s ur ge prot ec tion to g u ard aga inst s hort-term power interruption s E l ect r ica l Eq u i pm ent For l o n ger power int errup ti ons, if time permits s hut down a ll e l ect ri ca l devices and tum off electrica l br eake r s to prevent damage due to power s ur ges upon being ree nergized. b o rin g commun iti es w her e postal fa c ilities were open ( and packed with p eo pl e trying to get their mail). In some cases co mputers and supplies were driven to their final d est ina tions b y faculty or staff members. Much of this effort cou ld have been avoided wi th proper data storage practices. Th oug h th e r e ar e ce rtainl y secu rity and accessibi lity issues with off site data storage in a case lik e this in which faculty is forced to scatter to various l ocations wi th out suff i c i ent warning to retrieve or back up data, the ability to retrieve important in formation from a neutral site wou ld be in va luabl e On e such resource cu rrentl y under development is the Louisiana Opti ca l Network Initiativ e (LONl)----w hi c h will pr ovide a high-speed o pti ca l net work for researchers at a number of L ouisiana uni versi ti es, including Tulane. But until such networks are in pla ce and eas il y accessible to th e research commun i ty, individual in vest i ga tors must a cce pt the responsibility for ensur in g that their res earc h data are secure and readily retrievable. A list of other "Lessons Learned is show n in Tabl e 1. An area for further research is listed in Tabl e 2. B y Sept 26 resid e nts were bein g allowed back int o Or leans Parish on a limited basis so police escorts and con voys were no lon ge r nec essa r y. R ecovery trips to the cam pus co ntinu ed, and it was during the ensuing sixt o e i gh t-w eek period that the majority of computers and r esea r ch equip m e nt were remov ed to allow investigators t o con tinu e their research at ex ternal sites. In m ost instances, the investiga tors or th e ir repr ese ntati ves, were escorted onto the Uptown ca mpus by either th e dean of e n g ine e ring or his designee. All Sprin g 2006 TA BL E2 More Infor m ation Nee d ed There is an is s u e w ith vapor pha se vs. liquid ph ase s torage of biologicals: There i s a hi gh probability that fungal s pore s will be floatin g in LN 2 and if th e s torage tub es are submerged in th e liquid then there i s a c h a n ce of sa mple co ntamination. On the other hand a full dewar if left un opened, can keep samp l es co ld for months. Some kind of s tud y would h e lp cl a rify w h e th er liquid phase s tora ge is indeed sa fe for biologicals. visito r s to campus had to be cleared with the Offic e of Publi c Safety prior to th ei r v isits, and random identification checks from armed security officers were the norm A system was estab li s h e d for r eco rdin g institutional identifi c ation numbers for all e quipment removed from the campus. Investigators were allowed to remove eq uipm en t for research purposes but were informed that doing so cou ld ha ve insuran ce impli cations; i.e., if there was hurrican e re lated damage they may not be able to pro ve it since insurance adjustors had not yet arrived o n campus A few investigators moved their labs e quipment graduate students, and all-to host universities for the semester. Some c hose to remain at Tulane and carry out their research with g raduate students who had either re mained behind or r e turn ed. B y mid-November escorted vis its had vi rtuall y ce ased, cleanup o p e rations were well under way, and the D epa rtm en t of Chemical and Biomol ec ular Engineering was gea rin g up for the spring term. Tu l ane University officially opened to faculty and staff on Dec 19 2005, and the spring 2006 t er m began Jan. 16 2006, right on schedule. 0 87

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.t3_..ij 1111111 .._c _u_r_r_ic_u_lu_m __________ ) DESIGN PROJECTS OF THE FUTURE JOSEPH A. 8HAEIWITZ AND RICHARD TURTON West Virginia University Mor ga ntown WV 26506-6102 I t i s generally accep t ed that the chemica l engi ne ering pro fession is in a s tate of change. Fewer graduates from U.S. chemical eng in eering departments are ente rin g the pe troleum, petrochemical, and chemical industries since most expansion in these industrie s is not in the United States. More graduates from U.S. chemical engineering departments are entering product-based industries (e.g., pharmaceutical, food, new materials) ratherthan the traditional commodity-chemi cal-based industries (ethylene oxide, benzene, sulfuric acid).1 1.2 1 Therefore, changes in the undergraduate chemical e ngineerin g curriculum-which ha s been s tatic for about 40 years (not counting advance s in computing)-are imminent if not already in progres s Three sig nificant changes in the chemical engineering cur riculum are under way.r3 1 First of all, biology is now consid e red to be an "e nabling science, a l ong with chemistry and physics Some education in the life sciences will soon be re quired for accreditation 14 l Secondly, chemica l engineers need to be taught about product design, either instead of or in ad dition to process design It will become more important to teach batch operations, since the manufacture of new chemi cal product s will certainly involve batch rather than continu ous operations. Finally, over the pa s t generation, advances in chemica l engineering research have involved the ability to understand and to manipulate phenomena at the co ll oidal, nano molecular and atomic scales. A key issue is the effect on macro sco pic properties of colloidal-, nano-, molecular, and atomic-scale phenomena i.e ., s tructure-property relations. It i s time these advances became part of the undergraduate curriculum Radical changes to the traditional chemical engineering curriculum have been propo se d .'3 1 Changes are on the hori zon, although the speed and degree of implementation of these changes is not yet obvious. It could a l so be argued, however that traditional chemical proces s engineering must still be taught because the soon-to-retire baby boom generation must 88 be r e placed by newcomers equally capable of operating, main taining and updatin g existing chemical plants. Given the importance of the capstone experience in the undergraduate education proce ss, a question that arises when considering curriculum changes is: What will the capstone c h e mi c al engineering design project of the futur e look lik e? It is virtually certain that the capstone chemica l engineering project of the future will not involve sulfuric acid or ethylene oxide production. Instead, it may have a life science basis It may involve design of a product. It may involve multiscale phenomena i .e the effect of nanoor molecular-scale inter actions on the performance of the product. It is more likel y to involve batch proce ss ing than continuous proce ss ing And, it i s also possible that manufacture of item s and unit packag ing-two concepts far removed from traditional chemical engineering-will be included Joseph A. Shaeiwitz received his B S de gree from the University of Delaware and his M S and Ph D degrees from Carnegie Mellon University His professional interests are in design design education and out comes assessment. Joe is an associate edi tor of Journal of Engineering Education and he is a co-author of the text Analysis Syn thesis and Design of Chemical Processes (2 nd Ed .) published by Prentice Hall in 2003 Richard Turton received his B .S. degree from the University of Nottingham and his MS and Ph D degrees from Oregon State University His research interests are in flu idization and particle technology and their application to particle coating for pharma ceutical applications Dick is a co-author of the text Analysis Synthesis and Design of Chemical Processes (2 nd Ed .), published by Prentice Hall in 2003 Copyright ChE Divis i on of ASEE 2006 Chem i ca l Engineering Educati o n

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In an effort to injtiate a new capstone-design paradigm the yearlong capstone design project at West Virginja University for 2003-04 and 2004-05 involved biologically oriented, multiscale product designs. The se two projects are described in this paper More detai l s are avai l ab l e elsewhere 151 and from the authors. CLASS ORGANIZATION In the se nior year of chemical engineering at West Virgirua University, the entire cla ss works on a large project for two semesters under the direction of a st udent c ruef engineer. More details are pre se nted elsewhere. 161 Briefly, faculty members play ro l es: one is the client for whom the students are "hired" to complete a design project; another is the "vice president" of the students' company, who helps the students with tech nical matters The st u de n t chief engineer divides the class into groups, each headed by a group leader. The role of the chief engineer is to represent the entire team to the client and to provide leadership from the big picture perspective The group leaders receive assignments from the chief engineer and are responsible for completing the work within their groups. Assignments are deliberate l y vague and open ended. One goal is to force students to define their own work state ment with input from faculty member s Another is to learn materia l not normally taught in class The exact topics stu dents must learn are a function of the project. A further goal is to make s tudents realize that they will have to continue learning new material throughout their careers, and that they have the ability to do so. In the fall semester, the project involves researching alter natives and a feasibility study. For example, in ice cream pro duction, the assignment was to identify screen, and recom mend food product s for production, with attention focused on product s that have low-fat and/or low-carbohydrate alter natives. Students se t their own direction with a mmimum of input from the in s tructor s. The client chooses one alternative for design in the s pring se me s ter This is really the only op portunity for the instructor s to influence the direction of the project; however the client's choice is always one of the top two student recommendations ICE CREAM PRODUCTION Thi s project was completed by 26 s tudents over the course of the entire 2004-05 academic year. It started with a very open-ended assignment: to investigate opportunities in food processing, particularly those involving low-fat and low-car bohydrate alternatives. The market for these foods was to be analyzed, and the issues associated with prod u cing the low fat and low-carboh y drate alternatives were to be identified. A summary of the colloidaland molecular-sca l e issues iden tified by s tudents is shown Table l. Production of any of these TA B LE 1 Exa mpl es of Colloidaland Mo l ec u lar Sca l e Process i ng Challenges i n Food Ma nu fact ur i n g Prod u ct Processing Challenge Ice Cream Ice crys tal formation mu s t be kept to a minimum. Otherwise the ice cream has a grainy t ext ur e. Nut and fruit size must be contro ll ed to control the rheol ogy Proce ss ing condi tion s must be co ntroll ed to prevent nuts and fruit additives from b eco min g soggy. One method for making low-fat i ce cream have the same mouth feel as regular ice cream i s s l ow c hurnin g, a proprietary proce ss of Edy/Dreyers.1 5 1 By c hurnin g the ic e cream at hi g her pressures and lower t e mperature s, s m a ll er, more dispersed fat globules are formed that have si milar mouth feel to re g ular ice cream. Cookies Almond flour is often s ub st itut e d for wheat flour in lowcarbo hydrate cook i es. Since almond flour co ntain s more fat the re s ult is a chewier cook ie Granulated s u ga r i s required in cookie manufacture so that th e s u gar wi ll spread throughout th e cookie during baking Coarse s u ga r re s ult s in cracking. This h as impli ca tion s as to which s u gar s ub s titut e ca n be u se d in l ow-carbohyd r ate cookies Reduced-fat cookies require longer baking tim es to allow the ex i st in g fat to coa t th e flour and s u gar particl es For sandwich cookies to s tick together the surface energy of the solid must be higher than that of the fillin g. One way t o accomplish thi s i s to raise the temperature of the filling and add more fat to the filJing both of which reduce it s surface e nergy. (This i s also true for ice cream sa ndwiche s.) Bread Protein a nd fiber are of ten s ub s tituted for wheat flour in low-carbohydrate bread. Binding agents are required to hold these in g redient s together Dough cond ition ers are added for strengt h Cereal Bar s Bind ers are added to h old the cerea l pieces together. They crosslink to form a flow-resi s tant s tructure. There are t wo common binders. One involve s dipolar interactions between OH gro up s on gl u cose molecule s in the binder and the cerea l pieces. The other involve s COO groups bonding covalen tl y wit h the cereal pieces. Spring 2006 89

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products would make a good design project. Each involves batch processing of a product as well as manipulation at the molecular or colloidal levels to obtain desired macroscopic properties. Another feature involved but traditionally unfa miliar to chemical engineers, is packaging. Students used product screening methods to rank the alter natives .171 Ultimately, ice cream production to capture l % of the domestic market was chosen for a complete design. Pro duction of 1.75-quart containers plus some novelties (pops and bars, in this case) were included in the design Ice cream production involves traditional chemical engineering, prod uct design and multiscale analysis It involves application of principles of chemical engineering at scales from the mo lecular level to the process level. Ice Cream Science There are three categories of ingredi ents in the ice cream mix: dairy sweeteners, and additives. Milk, cream, and nonfat milk solids make up the dairy por tion of ice cream. Sucrose or Splenda is used to sweeten the mix, and s tabilizers and emulsifiers are added to give the ice cream the desired body and mouth feel. Significant quanti ties of air are also present in finished ice cream. Standard ice cream contains an equal volume of mix and air, or an "over run" of 100 % Premium ice cream, however, has an overrun of only 80 % to give it a richer more-creamy, mouth feel. Milk is a colloidal suspension of water, fat, and milk so lid s. Fat particles in the sus pension range in s ize from 0.8 to 20 m. The sugar-lactose-is also present in milk, at a concentration of about 4.9 % In lactose free" ice creams, the milk is treated with the enzyme lactase which breaks lactose down into the simpler sugars glucose and galactose. In this design, regular table sugar, or su crose, is used as a sweetener in all the ice cream mixes except the low-carbohydrate ice cream. Sucralose is used to sweeten the low carbohydrate ice cream because it is indigest ible but still sweetens the mix 20 15 Cl) "' o e:. z, 10 ;;; 0 u "' > 5 0 0 Stabilizers and emulsifiers are essential in the production of ice cream products. Both components help to give ice cream a smooth body and texture and help to improve the overall mouth feel of the ice cream. Stabilizers work by reducing the amount of free water in the ice cream mixture. This retards ice-crystal growth during s torage and also provide s resistance to melting Stabilization i s accomplished through two mecha nisms depending on the typ e of stabilizer used and both mechanisms may be involved depending on the structure of the gum used Charged gums, s uch as carageenan, help to reduce the amount of free water because the charged groups interact with water to restrict the movement of water mol ecules within the mixture. Branched gums, such as guar gum, also reduce free water within the system. This i s accomplished because the branched s ide chains contain hydroxyl groups that hydrogen-bond with water, a reaction that also reduces the amount of free water. Similarly, emulsifiers help to re duce fat-globule coalescence by stabilizing the fat globules within the ice cream matrix. Monoand diglycerides are the most commonly u sed emulsifying agents. The addition of sta bilizers and emulsifiers is particularly important for ice cream ba se mixe s that are lower in fat content, because whole milk already contains natural sta bilizing and emul sifying material s. Atkins Low-Carb Kroger Standard Haagen-Dazs Premium I I I 5 10 15 20 25 30 35 40 Sh e ar Ra te (1/s e c) Figure 1. Viscosity of different ice cream products 90 Figure 2. Block flow diagram for ice cream production. () Mixi n g I n gredient s Freezing Pasteurization & Aging Flavor Homogenization --,, Mixing Cartoning Hardening Chem i c al En g in ee rin g Education

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The viscosity of ice cream varies with the type. During a class tour of a local ice cream production facility, the host remarked that production of low-carbohydrate ice cream was "difficu l t on the equipment," which had been p l aced into operat i on before low-carbohydrate ice cream was developed. Further investigation revealed that many ice creams particu larly the low-carbohydrate vanillas, contain TiO 2 pigments to make the ice cream look whiter. It is possible that the TiO 2 colloidal particles cause erosion of process equipment. Stu dents also wondered whether there was a variation between viscosities of different ice cream types. One student who was doing research in the polymer research laboratory of our col league Rakesh Gupta, measured the viscosity of three types of ice cream. The results are shown in Figure 1. Low-carbohy drate ice cream is clearly more viscous than standard ice cream Fac i lity Design. A facility to manufacture, store, and ship ice cream was designed. Production volumes were 52 mil lion 1.75-quart ice cream containers (varying flavors) 2.3 million six-packs of sandwiches, and 4.3 million six-packs of pops (ice cream bars with sticks) The manufacturing pro cess of the ice cream facility is broken down into seven steps as i ll ustrated in Figure 2 A 5400-m 2 warehouse for ice cream storage was also designed It wa s de s igned to hold three months of production. Because of the need to refrigerate the warehouse the construction requires special insulation and the capital investment for this part of the process (>80 % ) dominates the overall fixed capital investment (almost $100 million)-a result that was not anticipated ..------<.'11 J---------------. Cold Storage Sprin g 200 6 Continuous Freezer System 6 C -102 Hardener Sy st em Ref r igeration Cycle. Refrigeration (600 tons) is required three place s : in the warehouse in the hardening step in ice cream production and for cooling the milk at the front end of the process. An ammonia refrigeration-cycle design used for the warehouse is displayed in Figure 3 The refrigeration cycle i s a traditional chemical engineering component of this de s ign Using the number of interstage coolers on the compres s ors and the type of cooling medium u s ed in E-101 through E-104 as decision variables, students optimized the refrig eration process. Steam Generation. In the facility low-pressure steam is u s ed for pasteurization for jacketed heating of the mixing equipment and for heating water for equipment cleaning These s tep s are necessar y to ensure that there is no product contamination by bacteria, which is part of good man u fac turing processes in food production. Therefore, a typical steam-production facility was de s igned Wastewater A system was designed to process wastewater from the ice cream manufacturing faci l ity. There were two rea s on s for this. First it wa s assumed that the ice cream plant would produce too much additional wastewater for an exist ing municipal wastewater facilit y. Second, based on infor mation from the local water authority having a water treat ment facility in-house appeared to be the less-expensive op tion Wastewater treatment is needed because the equipment must be cleaned daily generating significant amounts of wastewater The operation plan involves produc t ion on two Fig ur e 3 PFD for the optimized ammonia refrigeration s y stem unit 1. 91

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() Weighing & Figure 4. Mixing Block flow diagram for transdermal drug delivery patch manufacture. s hifts per day followed by a cleaning shift. Most of the cleaning is done using hot water. Economics. It costs approximately $0.56 to produce a 1.75-quart container of ice cream, in cluding the initial capital investment. Even with the markup associated with the food distribu tion chain, the process is very profitable. The net pre se nt value (NP V ) was found to be $97 million, assuming a 10-year plant lifetime and a 15 % before-tax rate of return A Monte Carlo a naly s i s s howed that there i s only an 8 % chance of losing money i.e ., an NPV le ss than zero Remark s from an ice cream expert at the final s tudent presentation indicated th a t prices for milk products could vary over a wide range, leading to significantly greater variation in the NPV. These factors were not considered in the students' analysis but could easily be in co rporated D ESIGN OF A T RANSDERMAL D RUG DELIVERY SYS T EM a b Inspection M K Patch Coating Drying Laminatior ---Cutting & Packaging M M 3 K K K 3 Stratum Epidermis Dermis Corneum M M C a K Patch Stratum Corneum Cartoning M M s K s c c .; C s C s ; C s Capillary Blood Wall C ,; Blood This project was completed by 11 s tudent s over the course of the entire 2003-04 academic year. It also started with a very open-ended as s ignment: to investigate alternative forms of drug delivery, and to suggest a product to be manufactured. Within the tran s dermal patch ca tegory students learned the properties that make a drug suitable for u se in a tran s dermal patch, which are: (1) low molecular weight (2) high potency so low dosage required (3) resi tance to enzymes in skin layer s, and (4) desire to have constant dosage in body over time. Item number 4 means that a transdermal patch would not be used to treat a simple headache, becau se, for a headache rapid entry of the drug into the Figure 5. Model for diffusion through skin la yers. Patch Blood k, k C,, V 1 C 2 V 2 Figure 6. Twoco mpartment pharmacokinetic model blood is desired. Students u se d productsc reening methods to choose between alternative drug s. 1 7 1 Ultimately production of a contraceptive transdermal patch for females was chosen for a complete design. 92 Patch Design. The patch contains norelgestromin and ethinyl estradiol. The proposed s ize of the patch i s 10 cm 2 manufac tured as a s ingle-la ye r matrix sys tem Che mi c al Eng in ee rin g Education

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Pressure-sensitive adhesives are the common form of ad hesive u s ed in transdermal s ystems. They are permanently tacky at room temperature they are ea s ily applied with light pressure and they do not require solvents for activation Polyisobutylene was chosen because it provides excellent adhesion in high-moisture environments and because of its low cost. Polyisobutylene has a surface ten s ion of 30-32 dyne/cm which is lower than the critical s urface tension of skin of 3856 dyne/cm depending on humidity and temperature There fore, the adhesive will wet the s kin-a requirement for adhe sion. This is an example of colloids cale considerations in the transdermal patch design. Skin penetration enhancers increase the mass flux of a drug across the desired surface area The driving force for the drug is the concentration gradient between the patch and the skin. The enhancer used in this patch i s crospovidone which draws water to the surface of the skin. Thi s in turn causes swelling which provides more surface area for diffusion. Excipients are ingredients within a drug product that are considered inactive, from a pharmacological perspective In this case, there is one excipient u s ed propylene glycol monolaurate which acts as an emollient. Manufacturing. The block flow diagram for manufacture of the transdermal patch is shown in Figure 4. It is a batch operation. First, the ingredients must be weighed and mixed. The drugs are mixed with the adhe s ive. The appropriate mix ing time and impeller arrangement are estimated using typi cal chemical engineering principles. 181 Then, the mixture is coated on the backing. Hexane is used as a solvent to help lower the viscosity of the solution and to ensure a well-mixed product. After coating the hexane is evaporated and is s ub sequently incinerated because it wa s determined that there was not enough hexane present to justify a recovery system. Next, the release liner is added to sandwich the drug/adhe sive mixture After inspection (as required by law) large sheets are cut into IO cm 2 patches packaged individually and then packaged again, three per carton. Finally, cartons of the three packs are packaged for distribution. Part of the design involved identifying good manufactur ing practices" in the pharmaceutical industry, which ensure that the product is pure and free of contamination. Economics. Students determined that the cost of manufac turing one patch is between $0 28 and $0 30, depending on employee salaries and the plant location. The U.S. pharmacy price for a similar, brand-name product is approximately $15 per patch Since this product is to be a generic version it was assumed that its price would be about half of the brand-name product. The markup at the pharmacy is assumed to be twice the price for which it was purchased. Therefore the estimated manufacturer s patch price is $ 3.75 Selling the patches for $3.75 per patch yields a net present value of $684 million assuming a 10-year plant lifetime and a 15 % before-tax rate Sprin g 200 6 A ... goal is to make students realize that they will have to continue learning new material throughout their careers, and that they have the ability to do so. of return. No information was available from industry sources to verify these assumptions or the resulting NPV estimate Mathematical Modeling. In the design of a transdermal patch the dose is a key factor to consider. The drug is deliv ered from the patch to the body by diffusion through the multiple layers of skin so students were required to model diffusion through multiple, immiscible layers. The flux of a given drug from a transdermal system into the body can be modeled as shown in Figure Sa. The result is +I I K 0 .i= 1 [ n l K TIM J J j= I (I) where C 0 is the concentration of the drug in the patch, K is the inverse of the resistance to diffusion of the drug provided by each skin layer and M is the partition coefficient of the J drug between a layer and the subsequent layer (M = C/C) J J I J It wa s found that the rate-limiting s tep is diffusion through the s tratum comeum layer So if it is assumed that the con centration in the blood is zero (C n = 0) the model reduces to Figure Sb and Equation (1 ) becomes (2 ) A pharmacokinetic model was also developed, which can be used to predict the concentration of the active ingredients in the blood. The model is illustrated in Figure 6, and the equations are dC 1 = -k 1 C 1 dt V 1 (3) dC 2 = k 1 C 1 -k 2 C 2 dt V 2 (4) where C 1 is the concentration of an active ingredient in the patch k 1 is the elimination rate constant from the patch, V I is the volume of the patch, C is the concentration of the active ingredient in the blood k : is the elimination rate constant from the blood, and V 2 ripresents the volume of blood in which the drug is distributed Students fit this model to pub lished data to determine the values of k and k 1 9 10 1 1 2 Multiscale Design. In terms of multiscale analysis, design of a transdermal drug delivery system requires design from the molecular scale through the macroscopic scale. These 9 3

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items are summarized in Table 2. At the molecular scale, the drug itself is designed. This is beyond the scope of this project. At either the molecular or nano sca les one find s the pres ence of excipients and/or enhancers in the patch The adhe DISCUSSION One of the advantages of a project s u c h as ice cream pro duction is that it ha s traditional chemical e n gineeri ng com ponents (e.g., refrigeration cycle, wastewater treatment, steam sive to hold the transdermal patch to the skin could involve design at multiple scales. Since the drug is mixed with the adhesive, ifthere were a molecular interaction be tween the drug and adhesive, it would have to be understood For an adhesive to stick, it must wet the skin, so an understanding of colloid-scale wetting phenomena is required The patch must be re moved without significant dis comfort, yet not become detached in the shower or during physical TABLE2 production) along with multiscale considerations, product design and manufacture and packaging De sign of a transdermal drug patch has a stro nger lif e scie nce component a nd involves more transport phe nomena-ori e nted mathematical modeling (i.e., systems analysis) than a traditional chemical pro cess design. Length Scales and their Application to the Transdermal Patch Problem nano scale the action of e nhanc ers and exc ipi ents at a molecular l eve l on the skin s urfac e co lloid sca le mechani s m of adhesion tran sde rmal transport phenomena micro sca le pharmacok:in e ti cs While the multiscale aspects of these projects have been identified the molecular-scale phenomena macro sca le product manufacture activity that causes sweating-both macro-scale phenomena. At the microscopic scale, the mechanism of transport of the drug through the skin must be understood. Modeling drug transport through the skin layer s is standard transport phe nomena Similarly there is system modeling, in which the pharmacokinetics of the drug in the body can be modeled. Finally, at the macroscopic scale, the components must be combined appropriately manufactured into the desired product, and packaged for sale. ASSESSMENT Two assessment measures were used. In one, the two in structors use a rubric to evaluate, se parately, all aspects of the final design report and oral presentation submitted by the students each semester. This rubric was developed in the con text of more traditional chemical engineering design prob lems. For example, since biology is not (yet) required in our curriculum, it is not listed as a science that students are ex pected to demonstrate an abi lit y to apply. The ability to learn and to apply biological concepts as needed is evaluated un der the ability to learn new material not taught in class. The complete rubric is available on the Web. 1111 Table 3 s hows the results, averaged for the two instructors, for both projects. The score of three indicates meets ex pe c tations and the score of four indicates exceeds expectations. Clearly, our assess ment of the students suggests that they exhibited superior performance in the ability to teach themselves new material. In our student evaluation of instruction it is possible for the instructor to add an individually defined question. Table 4 shows several such questions and the student responses. The responses are on a 5-point Likert Scale, thu s indicating student responses were all between "agree" and "s trongly agree." Therefore we conclude that the students involved in these project s believed them to be beneficial. 94 have not yet been incorporated into the design. For example, we do not beli eve that we are in a position to design a new drug or to manipulate the micro s tructure of ice cream. If, however a product design assign ment were based on a faculty member 's research, it might be possible to include molecular, nano, or colloidal-scale de sign aspects, especially if s tudent s were in a position to per form experiments. A reasonable question is what other design projects of this type are envisioned. The li st of potential li fe science-re lat ed projects is long and could include innovative drug-delivery devices (e.g., dru gs on a chip) or tissue grow th. Our class of 2003 designed a facility for the batch producti;:m of a mino acids. 1 51 Design of a microprocessor production facility would involve multiscal e phenomena and could also involve tradi tional chemical engineering in the production of ultra-pure water and in wastewater treatment. De s ign of an advanced material based on its microor nano -struct ur e is also pos s ible. The importance of multiscale phenomena in paper manufacture was r ecent ly presented, 112 1 so manufacture of fine paper products is a possibility. More detailed synopses of these project s are available on our design project Web s it eY 1 The final reports are also avail able to faculty member s by contacting the authors. CONCLUSIONS As the profes sio n of chemical engineering moves toward product development and design and away from process de velopment and de sig n a new paradigm for chemical engi neering education is evolving, requiring a new generation of capstone design proj ects. Two examples h ave been presented here. In ice cream manufacture multiscale considerations are important yet there are traditional chemical engineering com ponents included Production of other food products involves Chemical Engineering Educarion

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m a n y of th e sa m e co n s id erat i o n s. In d es i g n of a tran s d e nn a l dru g d e l i ve r y p a t c h li fe sc i e n ce co n s id era ti o n s, multi sca l e fac tor s a nd sys t e m s mod e lin g a r e r e quir e d. B o th in v ol ve a s p ec t s o f pr o du c t d es i g n. Th ey a l so r e qui re manufactur e a nd p a cka g in g of unit it e m stopi cs t ra diti o n a ll y fo r e i g n to chemi ca l e n g in ee rin g e du ca ti o n As th e c h e m ica l e n gi n ee rin g c ur ri c ulum c h a n ges in res p o n se to t h e c h a n ges in o ur prof es s i o n s imil ar d es i g n proj ec t s w ill fi nd t h ei r way i nt o c ap s t o n e ex p e ri e n ce s ACKNOWLEDGMENTS Th e foll ow in g s tud e nt s wo rk ed o n th e t ra n s d e nn a l p a t c h : M a tth e w And e r s on J e ffr ey Bi c k a r G r ego r y Hack e tt Jo se ph Kit z mill e r Lind say Kru s k a, John R a m sey, S a muel Smit h Crai g Tra v i s U g o c hi Um e l o, J e nni e Wh ee l e r and Cla y ton Wi ll iam s Th e foll o win g s tud e nt s wo rk e d o n i ce c r ea m produ c tion: J ess Ar c ur e Jon B a ld w in B e n ja min B a nk s, Adam B y rd Tim o th y D a ni e l M a ri a n a E s quib e l K y l e G a ll o Lin a G a l v i s, Jo se ph Jon es M a tth ew K aya tin D e nni s L e b ec D a ni e l M a l o n e Jo n a th a n Mill e r Jo s hu a M o unt s, D av id N e wc om e r R e b ecca Orr C o l ee n P e ll Mi c h ae l Pfun d Jam es Rho a d es Jo s hu a Rh o d es, R e b ecca S e ib e r t Ja m e s S im s Mi c ha e l V e l ez, William Whit e Ja so n Willi a m s a nd Joa nn e Wint e r. P or tion s of thi s pap e r we r e pr ese nted at the 2004 ASEE A nnual M e etin g, S a lt L a ke Cit y, UT s e s sion 3413 ( t ra n s d e nn a l patch ) a nd a t th e 2 005 ASEE An nu a l Meet in g P o rtl a nd O R s e ss ion 3 1 1 3 ( ic e cr e am ). REFERENCES I Cu ss l e r E L. and J Wei "C h e m ica l Pr od u c t E n g in ee rin g A/ C h E 1 49 I 072I 075 ( 2003 ) 2 Cu ss l er, E L. D o C h a n ges in th e Che mi ca l In d u stry Impl y C h a n ges in Curric ulu m ?" Ch e m En g. Ed ., 3 3 ( 1 ) 1 2 ( 1 999 ) 3 < http :// mi t. e du /c he-curriculu m /> 4 Crite r i a for Acc r edi tin g E n g i n ee ri n g P rog r a m s ( 2006 07 cycle), ABET In c B a ltim o r e p 27 5 < http :// www.c h e ce m r. wv u e d u / publi ca ti o n s / p ro j ec t s/ ind ex php > 6. S h a e i w it z J. A W.B Whitin g a nd D V e l ego l A Lar ge -Gro u p S n io r D esig n E x p e ri e n ce : T eac hin g R e s p o n s ibi l it y a nd L i f e l o n g L e arn in g, C h e m En g Ed ., 30 ( 1 ) 70 ( I 996) 7 T urt o n R. R .C. B a ili e, W B Whitin g a nd J.A. Sha e iwit z Ana l ys i s Sy 111 h es i s and D e s i g n o f C h e m i c a l P r oce sse s 2 nd Ed C h a pter 24 P r e n t ice H a ll PTR U pp e r Sa d d l e Ri ve r N J (20 0 3) 8 Old s h u e, J ., F luid Mi x in g T ec hn o l ogy, C h a pt e r 1 5 McGra w Hi ll N ew Yo r k ( 1 9 8 3 ) 9. Kydo ni eus A.F. a n d B. B e rn e r Tra n s d e rmal D e li ve r y of Dru g s Vo um e II C R C Pr e ss, B oc a R a t o n FL ( 1 987 ) I O Orth o E v ra F ull Pr esc r i bi n g I nf o rmati o n, Orth o -M c N e i l Pharma ce u t i ca l s, R a ri tan J ( Ma y 2003 ) 11. < htt p :// www c h e ce m r wv u .e du / u gra d / o ut co m es / > I 2 H ubbe M A ., a n d O.J R oja s, Th e P ara d ox of P a p e rrnakin g," C h em En g. Ed ., 39 ( 2 ), 1 46 ( 2005 ) 0 TA B LE3 As sessment Resu l t s for De s i gn Pr oject s As se s sme n t Patc h Ice C rea m D es i g n of e quip me nt und e r s t an d int e rr e l a ti o n s hip bet wee n e quipm e nt in proc ess 3. 0 3.0 Appl y c h e mi s tr y m a th ph ys i cs e n gin e er i n g s c i e n ce 3. 5 3.5 R eso l ve co mpl ex pr o bl e m int o co mpon e nt s 3 0 3.5 App l y eco n o mi c, ph ys i ca l co n s t rain t s a n d op t i mi za t ion m e thod s t o o bt ai n s o l ution 3. 0 3 0 Use of co mput erb ase d a nd o th e r inforrn a tio n sys t e m s 3 0 3 0 De m o n s t ra t e a bi l i t y to l e ar n n ew ma t e ri al n o t t a u g ht i n cla ss 4 0 4.0 D e m o n s tr a t e a bilit y t o fun c tion in ass i g ned ro l e 3 0 3 0 D emon s tra t io n of e thi c al b e h avior 3 0 3 0 Demon s trat e und e r sta ndin g of s ocietal impact and n ee d for a ss i g ned design 3 0 3.0 T A B LE 4 St ud ent Eva lu atio n of I n st ru ct i o n R es ult s Re s ult Gro up O ut o f As k e d 5. 0 Ta c klin g th e nontraditi o n a l probl e m p ose d in th e l arge gr oup proje c t e nh a n ce d m y c onfidence i n s o l ving ne w prob l e m s Patc h 4.9 0 I f e el th a t m y e xp e r ie n c e w it h t h e g roup d es i g n tau g ht m e t h e importa n ce of and the n eed fo r co ntinu o u s l y l e a rni ng n e w m a t er i a l. P a t c h 4 17 In m y caree r I w ill b e req u i r e d t o s o l ve p ro bl e m s a pp e arin g to be out si d e th e m a in s tr ea m o f c h e mi c al e n g ine e ring Ice c r eam 4 17 s u c h as foo d process in g. I f ee l c onfid e n t t h a t I ca n a ppl y m y c h e mi ca l e n g in ee rin g kno w l e d ge to an y a ppli ca ti o n Ice c r ea m 4.40 Th e t ea m wo rk ex p e ri e n ce in thi s cl ass w ill be va lu a bl e in m y futur e c a r ee r Ice cream 4 57 Sprin g 2006 95

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Random Thoughts ... A WHOLE NEW MIND FOR A FLAT WORLD RICHARD M. FELDER North Carolina State University Interviewer: "Good morning, Mr. Allen. I'm Angela Macher-project engineering and human services at Con solidated Industries. Senior: "Good morning, Ms. Macher-nice to meet you I: "So, I understand you're getting ready to graduate in May and you' re looking for a position with Consolidated .. and I also see you've got a 3 .75 GPA coming into this semes ter-very impressive. What kind of position did you have in mind ?" S: "Well, I liked most of my engineering courses but espe cially the ones with lots of math and computer applications1' ve gotten pretty good at Excel and Matlab and I also know some Visual Basic. I was thinking about control systems or design. I: "/ see. To be honest, we have very few openings in those areas-we've moved most of our manufacturing and design work to China and R omania and most of our programming to India Got any foreign l anguages?" S: "Um, a co uple of years of Spanish in high school but I couldn't take any more in college -n o room in the curricu lum ." I: "How wou ld you feel about taking an intensive langua ge course for a few months and moving to one of our overseas facilities? If you do well you could be on a fast track to man agement." S: "Uh .. ./ was really hoping I could stay in the States. Aren't 96 Rich a rd M. Felder is Hoechst Celanese Pro fessor Emeritus of Chemical Engineering at North Carolina State University He received his B.ChE. from City College of CUNY and his Ph D from Princeton He is c oauthor of the text El ementary Principles of Chemical Processes (Wi le y, 2005) and codirector of the ASEE Na tional Effecti ve Teaching Institute Copyright ChE Divi s ion of ASEE 2006 any positions l eft over here ?" I: "Sure, but not like JO years ago, and you need different skills to get them Let me ask you a coup l e of questions to see if we can find a fit First, what do you think your st r engths are outside of math and computers?" S: "Well, I've always been good in physics." I: "How about social sciences and humanities ?" S: / did all right in those courses-mostly A's-but I can't honestly say I enjoy that stuff" I: "Right. And would you describe yourself as a people person ?" S: "Um .. ./ get along with most people, but I guess /' m kind of introverted ." I: / see .... (Stands up.) OK Mr Allen-thanks I'll fmward your application to our central headquarters and if we find any slots that might work we' fl be in touch. Have a nice day." This hypothetical interview i s not all that hypothetical. The American job m arket i s changing, and to ge t and keep jobs future graduates will ne e d ski ll s beyond those that used to be sufficient. This message is brought home by two recent books-Thoma s Friedman's The World i s Flat 1 and Daniel Pink's A Whole New Mind1--that I believe s hould be required reading for every engineering professor and administrator. The book s come from different perspectives-the first eco nomic, the seco nd cog nitive-but make almost identical points about current global trends that have profound impli cations for education. An implication for engineering ed ucation is that we 're teaching the wrong st uff. Since the 1960s, we have concen trated almost exclusively on equipping s tudent s with analyti1 T.A. Fri ed man The World i s Flat .New Y o rk, Farra, ; Straus, & Giroux, 2005. D.H. Pink A Whole New Mind New Y ork, Riverh e ad Books 2005. Chemi c al Engineering Educati on

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cal (left-brain) problem-solving s kill s Both Friedman and Pink argue convincingly that most job s calling for those s kills can now be done better and/or cheaper by either computers or skilled foreign workers-and if they can be they will be. 3 They also predict that American workers with certain differ ent (right-brain) skills will continue to find jobs in the new economy: [I c r ea ti ve r esea r c hers devel o p e r s, and e ntr e pr e n e urs who c an h e lp th e ir companies s ta y ahead of the t ec hn o l ogy developm e nt cu r ve; [I d e signers capable of c reatin g pr o du c ts that are attra c ti ve as we ll as fun c ti o nal ; [I holistic multidis c iplinar y thinker s w h o c an r ecog ni ze co mpl ex patterns and oppor tuniti es in th e g l obal eco n o m y and formulat e s tr a t eg i es t o c apitali ze on them ; [I people wi th strong int e rp e rs o nal sk ill s that e quip th e m to es tablish and maintain goo d r e lati o n s hip s w ith c urr e nt and p o t e nti a l c ust o m ers and co mm e rcial partners; [I p eo pl e wi th th e lan g ua ge sk ill s and c ultural awar e n ess needed t o build brid ges betw ee n co mpanies and workers in d eve l op in g nati ons (w h e r e man y manufa c turin g fa c ilities and j o bs ar e mi g ratin g) and dev e l o p e d nations (w her e man y c ustom e r s a nd co nsumers w ill co ntinu e t o b e l ocated); Cl self-d ir ec ted l ea rn e r s, who ca n keep a c quirin g th e n ew knowledge and skills the y n ee d t o stay abr eas t of rapidl y c han g in g t ec hn o l ogica l and econom i c cond iti o n s Those are the attributes our students will need to be em ployable in the coming American engineering job market. The question is are we helping them to develop tho se at tributes? With isolated exceptions, the answer is no. We s till spend most of our time and effort teaching them to Derive an equation relating A to B and Calculate Z from specified values ofX and Y. We also offer them one or two lab courses that call on them to apply well-defined procedures to well designed experiments and we give them a capstone de s ign course that may require a little creativity but mostly calls for the same calculations that occupy the rest of the curriculum Nowhere in most engineering curricula do we provide sys tematic training in the abilities that mo s t graduates will need to get jobs-the skills to think innovatively and holi s tically and entrepreneurially, design for aesthetics as well as func tion communicate persua s ivel y, bridge cultural gaps, and periodically re-engineer themselve s to adjust to changing market conditions. Why don t we? It 's becau se people as a rule don t want to leave their comfort zones, and engineering professor s are as s ubject to that rule as anyone e l se. We are all comfortable deriving and solving equations for well-structured s ingle-di s cipline systems but mo s t of us are not so s ure about our abil it y to handle ill-d efi ned open-ended multidisciplinary prob l e m s or to te ac h creative thinking or entrepreneurship. So de s pite a crescendo of headline s and be s tse ller s about the growing exodus of tr a ditional s killed job s to developing coun tries ( including high-level re searc h and development job s, which are increasin g ly moving to India and China 4 ), many engineering faculty member s vigorously resist suggestions to make room in the curriculum for multidi sc iplinary courses and project s or anything that might be labeled "so ft. Even though most of our alumni in industry-95 %? 99 %? -a s ure us ( as they have done for decades) that they haven t seen a derivative or integral si n ce they graduated the traditional i s t s still insi s t that we can only produce competent engineers b y devoting almo s t every course in the curriculum to deriv ing and so lving equation s, analytically and with Matlab The s ame prof esso r s are no le ss re s i s tant to efforts to move them away from the traditional I talk you listen pedagogy toward the active cooperative, problem-based approaches that have been repeatedly shown to equip s tudents with the skills Fried man and Pink are talking about. ( See bibliography on p. 113. ) So far we ve gotten away with it, although sharply declin ing engineering enrollments in recent years s hould be a red flag. We can t count on getting away with it much longer however. Th e relentle ss movement of industry to computer ba se d de sig n and operation and offshoring of s killed func tion s and entire manufacturing operations i s not about to go away. On the contrary, as computer chips get faster and de veloping countries acquire greater expertise and better infra s tructure the movement will inevitably accelerate. The Ameri can engineering schools that respond by shifting toward more multidisciplinary problemand project-based instruction the way Olin, Rowan Ro se -Hulman the Colorado School of Mines and a number of others have already started to dowill s urvive The sc hool s that try to stick with bu s iness a s u s ual ma y not. 0 3 I/ yo u don t think this i s already happening in e n g in ee rin g c h eck o ut a 2005 NAE R e p o rt ca ll e d Ojfs/10rin g and th e Future of U.S. Engi n ee rin g: An Overview ," . 4 S L o hr Out so ur c in g is Climbing Skills Ladd e r New Yo rk Tim es F e b 1 6, 2006 Thi s artic l e r e p o rt s that o/200 multinati o n a l co rp rations s ur veyed, 38 % sa id th ey planned t o "c han ge s ubstantiall y" th e wor ld w id e distribution of their R & D wo rk i n th e n ex t thr ee yea r s ... and thi s particular t r e nd i s s till in its infan cy. All of the Rand o m Thou g hts columns are now available on the World Wide Web at http://www.ncsu edu/effective teaching and at http : //che.ufl edu/-cee/ Sprin g 2006 97

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98 Maintaining Conne cti on s with U ndergraduat es Continued from page 83 requested to provide contact information for classmates ( e -mail addresses, ce ll phone numbers etc.). If they we r e uncomfortable doin g thi s, th ey were asked to contac t c l assmates themselv es and e n co urage them to contac t one of the faculty. This approach, along with postin g a request on the departm e nt's blog (see Prof esso r Ashbaugh's account), still only allowed direct contact information to be gathered for about 50 percent of our students. The junior and senior classes, however had set up their own Yahoo groups prior to the storm which meant departmental emails ultimately reached more students. In one instan ce, a student posted fa c u l ty mes sages to a Web site the student had built specifically for sharing department information with classmates. I n ret rospect, gathering a l t e rnat e con tact information prior to Katrina as a regu l ar part of getting acquainted with students would have allowed d e partment outreach ef forts to be more effective after the hurricane. Student feedback from phone co nversations led to the reali z ation that our co r e co urse c urriculum was aligned with only a fraction of other c h e mical engineering pr o grams. Our unique P ractice School program durin g th e senior year 131 requires that most core courses be offered a semester earlier than other programs As a result stu dents found it c hallenging to find the chemica l engi neering cou r ses they need e d. Of particu l ar concern were the seniors and their need to comp l ete a capstone d e sign course before graduation Within a day of re cog ni zi ng this issue the consensus from the facu l ty was that our process design course would be offered durin g the spring semester. This information was quick l y co mmu nicated to the seniors. The speed with which de c ision s of this type were mad e and co mmunicated ultimate l y affected the options our students had during fall regis tration. Since Katrina made landfa ll the weekend be fore the semester started, howeve, ; even the best efforts meant students began att e ndin g classes at other uni versities two to three weeks late Many students evacuated New Or l eans without their textbooks or notes B ecause of the broad scope of most c apstone design c ourses the most affected group was those seniors who managed to e nroll in this course. A s a result, the facu l ty member who would have taught this course w i t h in our department during the fa ll semester offered to provide supporting information from books that the students owned but left in New Orleans. Those students who attended ot h e r universities in the fall were request ed to send us th e name of the uni vers it y and the courses for which th ey were reg i stered. This pro vided a means of double c h ec king what th e student thought was an equiva l e nt co r e co urse. If th e cou rs e was not adequately equiva l en t th e st ud e nt was quickly noti fied. Under the difficult c ir c umstances, many s tud ents pragmatically chose to take th eir remaining non-Ch cou rses durin g the fall. Near th e e nd of September, the faculty began discuss ing the course schedule for the sp r ing and La g niappe semesters. From the fall r eg istration information pro vided by our students, it b eca m e evident that offering all co re co urs es during these two semes t e rs wou l d b e a r e quir e ment in order to keep the stu d en t s on tra ck. B y mid-Octobe,; a course sc h edu l e for both semesters had b een established w hi ch met this objective R egis trati on for the spring semester at Tulane began in ea rl y November. Two weeks prior to registration, all students were sent an e-ma il r e qu es ting th ey updat e their fall co urse-enrollm ent inf o rmati on. In this e -mail stu dents were also inf ormed that th ey wou l d be able to co ta c t three d e partm enta l adviso r s ( Drs. Mitchell, J o hn, and Prindl e) b y phon e for advising assistance over th e five-day p er i od just prior to the beginning of registra tion. This call cente r setup provided t h e students wit h assistance in addressing their reg istrati on questions. Since th e university Int e rn et and e -mail servers were r es tored in mid-O cto b e 1 ; th e re was no problem co nta c tin g all of our students usin g th e ir university e-mail addresses The response to this request was s ubstantially high e 1 '. Several c hallen ges had t o be overcome in manning the ca ll cente r Since the ca mpu s was closed and secu rity was ti g ht, d epa rtm e nt offices cou ld not b e entered without special permission. In addit ion service to d partment phones was not activated until the second day. Despite obstacles, the ca ll center was ultimately suc cessfu l in providin g students w ith assistance in address ing their co n ce rns prior to r eg istration All of thes e efforts in esta blishin g and maintainin g th e faculty-student connection were diffi cu lt und er the c hallen g in g co nditi ons. W e believe howev er, that they hav e forg e d even stronger ti es between both grou ps As a r es ult of these ex peri ences, so m e students feel more comfo rtable discussing probl ems w ith faculty. F acu i ty interest in our students and their well-being ha s in creased as well Whil e b o th gro ups looked fmward to th e start of the spring semester and a return to a sense of normal cy, that normal state will be distinctly differ en t. And, in man y ways, b etter. 0 Che mi ca l Engine e rin g Ed11catio11

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INIRODUCIION TO A SPECIAL SECTION ON THE Patten Centennial Scientific Workshop: THE NEXT MILLENNIUM IN CHEMICAL ENGINEERING CHRISTINE M. HRE NYA University of Colorado Boulde, ; CO 80309-0424 H. SCOTT FO GLER University of Mi c hi ga n Ann Arbo,; MI 48I09-2I36 Over the pa s t several years, a number of chemical engineering programs around the country have been honoring the 100-year anniversaries of their origins. The 2004-05 academic year marked a similar time at the University of Colorado. In 1904 -0 5 coursework for a B.S in chemical engineering included Slide Rule Sur veying, Oil and Fuel Laboratory and Heat Treatment of Steel whereas today 's curriculum includes courses such as Engineering Computing, Environmental Sepa rations, Polymer Science Particle Technology, Tis s ue Engineering and Pharmaceutical Biotechnology. Simj Armstrong (MIT), Arup Chakraborty (UC Berkeley) Ed Cussler (Univ. Minnesota) Mike Doherty (UC Santa Barbara) Richard Felder (NC State) and Jerry Schultz (U C Riverside ) -see Figure 1 next page. The work shop consisted of two parts namely oral presentations and panel discus s ions Trus feature section is intended to s hare the se exchanges with the greater ChE community In the first portion of the wo rk shop, each of the seven participant s was asked to give an oral presentation on a topic of his or her choice, with a theme that is both broad in scope and forward thinkmg. An ordered listlar-if not greater changes to the chemical engineering discipline are expected during the next cent ur y. To commemorate the centennial year, a scien tific workshop dedicated to discussions on the fu ture of the discipline was hosted by the Department of Chemical and Biologi ca l Engineering at the University of Colorado on Feb. 3 and 4, 2005 The participants included Professors Kristi Anseth (Univ Colorado) Bob Spring 2006 Christine M Hrenya is an associate profes sor of chemical and biological engineering at the University of Colorado She joined the fac ulty after receiving her B S from The Ohio State University and her Ph D from Carnegie Mellon University. She has given over 50 in vited lectures on her research in particle tech nology, the current emphasis of which is granu lar flows f/uidization aerosol dynamics and related computational methods H. Scott Fogler. After receiving his Ph D. from the University of Colorado he joined the Uni ve rsity of Michigan where he is currently the Ame and Catherine Vennema Distinguished Professor of Chemical Engineering. He is au thor of the text Elements of Chemical Reaction Engineering. His current research interests are in the areas of colloids, wax gellation kinetics, dissolution kinetics of zeolites and the pharma cokinetics of acute toxicology He has graduated 36 Ph D students in these and related areas Copyright ChE Division of ASEE 2006 ing of the talks is given in Table 1 next page. Corresponding written perspectives were re quested of each partici pant; these perspectives are contained in the ac companying gro up of articles. The manu scripts cover pedagogi cal issues (Professors Armstrong and Felder), a view on the current chemical industry (Pro fessor Cussler), and outlooks on emerging areas (Professors Doherty and Schultz). 99

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100 The Next Millennium in ChE Figure 1. Participants in the Patten Centennial Scientific Workshop University of Colo rado February 2005 Top row: QANDA ArupChakraborty, J e rry Schultz Kristi Anseth. Bottom Row: Bob Armstrong, Richard Felder Mike Dohert y, Ed Gussler. The second portion of the workshop comprised two panel discussions, both of which were driven by questions from the attending faculty and graduate students. A paraphrased overview of this exchange, grouped according to topic, is given below. The respondents are indicated according to their initials (see Table 1). Since these discussions took place after individual presentations the reader may choose to read this portion after the ensuing manuscripts to keep the chronology of the interactions intact. Curriculum Question (to BA): How do you envision the curriculum change you have proposed occurring (se e related persp e ctive by Bob Armstrong)? BA: I think we should start with a clean slate and start by adding back in the most important areas and then stop adding when four years are full. I think the approach should not include adding more classes than we currently have as that will lead to an overcrowding of schedules and then the students would have no time to think about what they are learning. We have not changed the curriculum in the last 40 years due to the large research engine created after World War II. Faculty were too busy with research to improve significantly the content in the classroom. Faculty have to take time from research, for examp l e to write textbooks or Web modules. We need to do this together as a community of universities. You have got to reward faculty for implementing change. EC: There is no way that we could possibly do what Bob is saying. Also, committee books are really bad usually. I think modifications need to be done one course at a time. Let me liken it to the past when periodic tables were put on the classroom walls At that time, boiling points were the only important properties we TABLE 1 Presentation Listing Participant Title Prof. Richard Felder (RF) Teaching Engineering in the 21st Century with a I 2th-Century Teaching Model: How Bright is That? Prof. Bob Armstrong (BA ) A Vi s ion of the Chemical Engineering Curriculum of the Futur e Prof. Arup Chakraborty (AC) Quantitative Cellular and Molecular Immunology : A New Opportunity for Chemical Engineering Prof. Jerry Schultz ( JS ) In Vivo Biolmaging : Advance s and Challenge s Prof. Ed Cussler (EC) A Different Chemical Industry Prof. Mike Doherty ( MD ) Crystal Engineering : From Molecul es to Produ c t s Prof. Kristi Anseth (KA) Chemical Engineering in 2020: Return of the J.E.D.I.? Ch e mi c al En g ineering Edu c ati o n

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The Next Millennium in ChE needed to know because everything was petrochemicals. ow, chemical engineers are u s ing the information on the periodic tab l e Question: With all the changes and additions that have been s ugge s ted do you think there will need to be a five year undergraduate degree ? Or i s it time that we separate the curriculum into new majors (e.g., tissue engineering, metabolic engineering)? R F: We cannot put in all the content, si nce the content i s always changing. We have to emphasize how to learn skills, flexibility BA: You need to learn a good way of thinking-the courses are just vehicles. I think it is a mi s take to fractionate i nto subareas at the undergraduate level. As a career evolves you are always introduced to new areas, so you learn to augment knowledge. Incidentally the renaming of many departments that has occurred recently-to include "bio" in their name-i s very different than the splitting into subareas we are talking about. The inclusion of "bio" in a department name reflect s the change in our underlying molecular core science from chemistry alone to a combi nation of chemistry and biology EC: If you put in new material you have to chop out fluff. We can do that by compressing courses (e.g., transport phenomena). But we also need to adapt to what is relevant. For example, I think it i s a tragedy that at Minnesota we teach thermodynamic s without coveri ng the topic of ionic so lution s, which has tremendous biological relevance. KA : It is important to consider which industries we want to serve when implementing changes into our curriculum. Textbooks Question: A number of the items discus se d thus far have been about modifying courses and teaching new courses. One problem set I fore see i s : Where are the textbooks, when will they come, and how will authors be rewarded? MD: Scholar s are responsible for writing research paper s, book s, patents, and grants. There is a need to de emphasize papers and make a g lobal contribution like writing text s. It 's so hard to write a book Role models are key-if role models write book s then others will be written; if the y don't, then there will be no books. A large problem is that there i s in s ufficient r ewar d for writing text s. evertheless, academics s hould do it as part of their job. R F: It is hard to write books hard and time consuming. Don t write a book before yo u have tenure Rewards ? Don t do it for rewards. A book only counts as a publication and the effort it takes is the same as for 25-50 publica tions Write it because you want to write it-it will be a better book if it 's a labor of love. B A: People need to step forward and do it-or at least convince others to do it. One reward is that the reputation of the school gets better when book s are written by faculty. The rewards are not well-translated to individual rewards. One answer may be to get teams of faculty to write book s. The books become much more interesting and have broader perspective if the y are done as truly collaborative efforts, and there 's le ss work per person Role of Biology Question (to J S): What do you see as the future for division of labor between material s sc ience and bioengineering ? J S: We will have some aspects of materials science tailored to bioengineering. Why should a name be changed to Biochemical Engineering ? There was no change to Pla s tic Chemical Engineering when plastics were the popular topic in chemical engineering. To be successful, engineering programs must collaborate with true biology pro grams. Also engineers design new products based on physics chemistry, and biology. Now that we can manipulate biology, biology is becoming more quantitative. Question (to AC): Did basic biology prepare you for the biological research you are undertaking? AC: The curriculum Bob talked about i s exactly what i s required. Learn the general idea and work from the molecular up to the macroscopic. Spring 2006 JOI

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The Next Millennium in ChE Teaching Methods Question (to RF): Do you believe distance l ear nin g is better? I m asking abo ut isolationism vs. l earning in the presence of other st udents ? RF : Compared with an active-learning class, distance l ea rnin g is not better. There are some things technology can never rep l ace. I don 't believe sof tware will ever be able to motivat e st ud e nt s That's not to say we can't supp l ment an active -l earning classroom with technology. Question: How should industry per s pectives be incorporated into the under grad classroom? RF: Take industry problem s and bring them into the classroom. Use a problem-solving method and let st ud ents take the lead in making decisions. JS: Bring in industry representatives to be a part of the de sig n team and probl em-so lvin g effort. Use real corpo rate resources and financial s upport to so lve re a l relevant industrial problems. MD: From real-world consulting experience with DuPont I under s tand that engineers typically have very s hort windows in which to make decisions with limited inform atio n. It is important to develop skills to quickly a nd hierarchically make these decisions Each result shou ld yield a "yes" or no response for continui n g or changing paths EC: Define complex problems and have some proce ss for judgin g if a commercial product is likely to work. Expose students to s ituations where they have to make decision s with limit ed data. Enrollments I Future of the Discipline 102 Question: What is happenin g with ChE enrollments? EC: Although we are seeing decreasing enrollments, we s hould look at the bigger picture. There has been an increase of 50 % in ChE programs and a decrease in enrollment-that makes sense On my way h ere, I was doing a little re sea rch and did you know that there are 11 Ph D programs in the state of Ohio-that's si ll y! I think it is time to s tart killing program s for under gra duate s and graduates. BA: Undergraduate enrollment i s on the increase again. In 2000, there were 6,000 undergraduates enrolling per year. Enrollment since 197 3 can be fit with a s ine wave and see m s to follow job growth Times change. It is up to educators to know what industrie s are growing/shrinking and mak e students aware of it. My concern is not so much at the B .S l evel as it is to where are all the Ph.D .s are going to go for jobs ? AC: Ph.D enrollment is flat during the sa me time JS: In C h E, enro llm ent varies up to about 10% a year. Th e amount of hi g h schoo l graduates going into the field of engineering, however is abo u t the same. It 's a ll dependent on jobs Question: Say I am a hi gh sc h ool senior who i s really good at math and sc ienc e. H ow would you convince me to be a chemical engineer? JS: Out of all engineering, chemical engineer in g has the widest range of basic scie n ce. Chemical engineering offers st ud ents a good systems base for the next 30-50 years. BA: Chemical engineering is preparation for a diver se range of career types. MD: Our primary asset is that we can provide quantitative solutions. This differentiates us from chemists, biologist s, etc. With a ChE B.S. one can go out into the real world with a good-paying job. C hemi sts and biolo gists tend to have a more difficult time finding more challenging, high er-pay in g jobs at the B.S. lev e l. RF: Thi s i s the on l y discipline that can put together so man y scie nce s. Chemical engineers can be found in many, if not mo s t technical field s in indu s try. A l so, mo s t st udent s don't know what they are interested in, so it keeps door s open (e g., environmental, heath care). Chemi c al En g ine e ri11 g Edu c ati o n

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The Next Millennium in ChE Globa l Competition Question: With the battle for global economy and our standard of living in jeopardy, what are your thoughts on lower-cost plants and re sea rch moving to other countries? How do we innovate and bring new products/technolo gies to market quickl y to win? What can faculty do? BA: We need to teach our s tudents marketing how to identify real needs and how to so lve problems to meet those needs We can only s ucceed if we innovate-n ot by becoming a service-based country. One minus for the United State s is that our culture is not one that tends to save money There are concerns that we will not have money required for inve s tment in R&D. MD: There is a natural progression in history that the same main group of countries innovates and the new technologies/product s become more commodity and move to other places, e.g., steel. In the 1880s the 20 richest places in the world included North America, Europe and Australia. In the 1980 s the list had not changed much, with few exceptions, including the addition of Japan to the li s t. It i s fairly hard to sc rew thing s up! Well-estab lished sys tems and s tabl e governments lead me to believe thing s wi ll remain the sa me. Energy and Water Research Question : In the next 50 years, what will be the biggest problem of the world and what role will chemical engi neer s play in solving it ? EC: Energy and water. I do not think ChEs will dominate health care or food Regarding water, ultrafiltration to remove viruses is needed. Regarding energy, gas will cost $6 a gallon in 10 years. Because of that there will be a renais sa nce to energy re sea rch A hydrogen economy is controversial a nd nonsensical. Fuel cells will need a major breakthrough, and one which is more applied in nature than univer s ities are used to. Thus universities won't dominate fuel-cell r esearc h MD: Energy is a huge problem-a national strategic problem. The developing world, including India and China, will increase the demand for energy. Two million cars were so ld in China last year. In 10 years, there will be more cars in China than in the United States. India will be m u ch the same as China. Bombay today is wall-to-wall cars. There will be a mas s ive demand for energy, and not a ll will come from fossil fuel s due to CO 2 prob l ems An H 2 economy does not change that bec a u se H 2 is also from fossil fuels. The best pro s pect is nuclear energy. Also methane i s a big area that need s re sea rch funding. Currently, nothing can be done with methane unle ss it is compressed to LNG ( liquefied natural gas). Right now, 4 billion cubic feet of methane is flared per year That amount of energy i s equivalent to 300 million barrels of oil. If it were liquefied and consumed by offshore units the energy produced would be very useful. Methane can a l so be changed to other fonn s for tran s port but it is not a priority to the government so success is s low coming. ational governments need to make priorities balancing CO 2 generation, global warming, and the risk s of nuclear energy. A s uccession of U.S. governments have had their heads in the sand, which i s a s trategic mistake for this country. BA : Hydrogen is only a carrier-the energy must come from some primary source such as nuclear. There is a huge need for energy carriers for automobiles. Other areas of energy research include biomass and carbon seques tration so that CO 2 problems can be alleviated. There are of cour se, many a lt ernative energy sources including solar (most expensive now ), wind (fa nn s are unplea s ing aesthetically but most economically so und right now) and biomass (two time s the cost of wind). We need a government willing to admit that energy is a problem and then federal research money will be available. One really good way to get revenue for research is to tax gasoline at something on the order of 10 to 50 cents per gallon. ACKNOWLEDGMENTS We are grateful to the numerou s graduate students at the Department of Chemical and Biological Engineering at the University of Colorado who volunteered their time and helped make this workshop possible. 0 Spring 2006 / 03

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( The Next Millennium in ChE ) A Vision of THE CURRICULUM OF THE FUTURE ROBERT C. ARMSTRONG Massachus e tts Institute a/Te c hnology Cambridge, MA 02139 0 ver the past 40 years the discipline of chemical en gineering ha s undergone dramatic change s We are no longer a discipline largely coupled to a single industry namely the petrochemical industry. Rather our gradu ates go to a wide variety of industries including chemicals, fuels, electronic s, food and consumer products materials, and biotechnology and phannaceuticals. 1 1 1 Moreover the character of the chemical industry has changed significantly particularly in recent years: l!"'.l the c h e mi c al industr y is t o da y ve r y much a g l o bal ent e rpris e; l!"'.l co mpani e s ha ve b e en r es hap e d b y a se ri e s o f m e r ge rs a c qui s iti o ns a nd spin-off s; l!"'.l som e maj o r c h e mi c al c ompani es ha ve be c om e life s c i e n ce co mpanies and spun o ff their chemical un i ts ; l!"'.l and th e tim e -to-mark e t f o r n e w products has b e en si g nificantl y shorten e d. Similarly the research enterprise in chemical engineering has exploded over the past 40 years both in dollar volume and in breadth. The exciting research opportunities that we explore today as a discipline were well illustrated in the "Fu ture of Chemical Engineering Research sessions at the 2004 Annual Meeting of AIChE. Particularly notable shifts in re search over this period include much more biologically re lated research and a much stronger molecular perspective in the research Over this same 40-year period the undergraduate curricu lum in chemical engineering has remained nearly unchanged. The stagnation in the curriculum is well illustrated by Figure I which is taken from a paper by Olaf Hougen.12 1 The flow chart in the figure shows the evolution of the curriculum de cade by decade from 1905 to 1965. In each decade, new content entering the curriculum is shown as well as material that was removed in order to "conserve mas s The center of each box defines a core theme(s ) for the decade I would like to make two observations about this figure. First over the 60 years shown, the curriculum was very dy namic with significant changes in each decade Second by 1965 we had developed a curriculum for undergraduate edu cation that is very nearly the same as today's. Why is this? It is possible that after 60 years of hard work on the curriculum the discipline arrived at a more or less timeless implementa tion. But this seems hard to believe in the face of all of the change that has taken place over the past 40 years outside of the curriculum On the other hand it is possible that we have simply not paid the attention we should to curriculum devel opment over this period. This is what I believe has happened This same period has seen an enormous growth in federal research funding in universities, and this growth is reflected in the large number of doctoral research programs in chemi cal engineering around the country. This research has created valuable intellectual growth in our community, but it con sumes an enormou s fraction of the time of our faculty mem bers just to keep the research engine running with grant proR ob e rt C. A r mst r o ng is Chevron Professor and head of the Depart ment of Chemical Engineering at the Massachusetts Institute of Tech nology He received a B ChE. from the Georgia Institute of Technol ogy in 1970 and a Ph.D in chemical engineering from the University of Wisconsin in 1973 His research interests lie in the areas of poly mer molecular theory polymer fluid mechanics rheology multiscale process modeling transport phenomena and applied mathematics He is co-author of the two-volume text Dynamics of Polymeric Liq uids which has been named a Citation Classic Copy r igh t C hE Di vis i on of ASEE 20 06 104 Ch e mi c al En g in ee rin g Edu c ati o n

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C IN FL OW (/) TRASPORT PHENOMENA PHYSICAL MEASUREMENTS l'J DI FFERENT IA L EQUATIONS COMPU TER PROGRAMMING a. :iJ ifi ill 5@ _LT APPLIED KINETICS PROCESS DESIGN REPORT WRITING S PEE C H INCREASE IN PHYSI CA L C HEM ISTRY UNIT OPERAT I ONS IT ORGANIC CHEMISTRY ChE THERMOND YNAMICS PROCESS MEASUREMENTS AND CONT ROL INCREASE IN PH YS ICAL C HEM ISTRY a. UNIT OPERATIONS GE NER AL C HEMISTRY a; w :J 0 MATERIAL & ENERGY BALANCES Ir FUNDAMENTALS a ill WI UNIT OPERATIONS 0 () INDUS TRI AL CHEMISTRY METALLOGRAPHY APPLIED ELECTROCHEMISTRY TECHNICAL ANALYSIS PYROMETRY SHOPWO R K STEAM AND GAS TECHNOLOGY CHEM I CA L MANUFACTURE PRINCIPAL D E V EL OPMENTS DE VI TRANSPORT PHENOMENA PROCESS DYNAMICS PROCESS ENGINEERING COMPUTER TECHNOLOG Y DECADE V APPLIED KINETICS PROCESS DESIGN DECADE IV ChE THERMODYNAMICS PROCESS CONTROL DECADE Il l MATERIAL AND ENERGY BALANCES DECADE II UNIT OPERATIONS DECADE I INDUSTRIAL C HEMISTR Y The Next Millennium in ChE ) OU TFLOW GRAPHICS SHOPWORK REDUCTION IN UNIT OPERAT I ONS MATERIAL AND ENERGY BALANCES INDUSTRIAL CHEMISTRY MET A L L OG RAPHY MACHINE DESIGN STEAM AND GAS TECHNOLOGY REDUCTION IN SHOPWORK INDUSTRIAL CHEMISTRY MECHANICS STEAM AND GAS TECHNOLOGY APPLIED ELECTROCHEMISTRY CON TRACTS AND SPECIFICATIONS REDUCTION IN MECHANICS MACHINE DESIGN DESCRIPTIVE GEOMETRY HYDRAULICS SURVEYING GAS MANUFACTURE & DISTRIBUTION FOREIGN LANGUAGES REDUCTION IN MECHANICS & QUANTITATIVE CHEM ISTRY Mathematics Physics Figure 1. Changes in a typical undergraduate chemica l engi neerin g c urriculum during 60 years. The initial curricu lum in 1905 consisted of separate courses in c h e mi stry and conve ntional engi n ee rin g 131 Computer Science po sa l s, co ntractor s' meeting s, review panels, annual report s, e tc The pri ce ha s been n eg l ec t of the curricu lar content in chemical engineering and a widening g ap between the re sea rch don e in modern chemical engineering and the content tau g ht in our under gra du ate program s. Materials Science Structured Fluids Electrical Engineering Microelectronics EMS The opportunities for chemical engineering today are great (see Figure 2). We are uniquely positioned at the interface between molecular scie nces and e n gi neerin g, and thi s afford s u s man y opportunities in a Chemistry Mecha n i c al Engin e eri n g broad range of technologie s th a t li e at the int e rfac e between chemical engineering and other science and engineering fields. Thi s image of chemical engineerBiology Civil Engineering ing creates a number of ten sio n s in our curriculum. There i s a s trong outward pull on our curriculum to ward the many disciplines with which we interact at the interfaces in Figure 2. The opportunity to teach Figure 2. Chemical e n g in eering has a spec ial position between the molecular scie n ces and e n gi n eer ing our students more about these particular areas of te c hnolo gy i s exciting educationally, but it doe s tend to ha ve a fragment ing effect on the discipline. Oppo si ng the strong outward pull is an equally compelling need to look inward at the core of chemical engineering. Some department s have dealt with thi s ten s ion by developing curriculum track s in s pe c ialized ar eas. Students begin by taking a common core in c hemical engineering and then specialize in a number of technology areas e.g., biotechnology materials. An alternative approach, Spring 2006 proposed here is to refocus on th e core content of chemical e n g in eeri n g. Thinking clearly about w hat co nstitute s the core of chemical e ngineerin g that will make our future graduates key contributors in interdisciplinary problems is esse ntial. It is important to remember that the current core we teach was de ve lop e d when c h e mi ca l engineering was de sc ribed b y the horizontal axis in Figure 2 That i s, chemical engineering was dominated by the intersection of chemistry and mechanical engineering W e need to reexamin e whether that core i s the 1 05

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( The Next Millennium in ChE appropriate core for the two-dimensional image in Figure 2. The broad range of app li ca ti o n s of c h em i ca l engineeri n g can be included in the curriculum by way of examp l es, problems, It is possible that after 60 years of hard work on the curriculum the discipline arrived at a more or less timeless imple mentation. But this seems hard to believe in the face of all of the change that has taken place over the past 40 years outside of the curriculum. case studies, and laboratories In this way we maintain a com mon education for all chemical engineers that demonstrates the versatility of the degree to all of our students. CCR/NSF FRONTIERS IN CHEMICAL ENGINEERING EDUCATION WORKSHOPS The opportunities for reform in chemical e n gineering cur ric ul a are so compelling and broad that an appropriate re spo n se requires wide-ranging participation across the e ntir e discipline. This is important for a number of reasons. First the opportunities/frontiers are too broad for any one depart ment or several departments to address effectively. Second the costs-time and money-of developing new ed u ca ti ona l materials are too high for any of us to absorb a l one. Finally the coherence resu lt ing from a joint effort will serve the di cipline well in maintaining a clear identity to the world (po tential students industry and government), ensuring good manpower supp l y to industry and to our grad u ate programs and e n s u ring that curric ulum developments a r e u se d Nearly I 00 fac ul ty members from 53 universities along with industrial representatives from five different companies met in a series of three workshops sponsored by the Co un cil for Chemical Research and the Nationa l Science Foundation to discuss curricular oppor tuniti es and to map out a path for ward Below I will highlight some of the key fi n dings of the workshops I encourage you to look at the detailed work prod uct a nd proceedings from these works h ops w hi c h can be found at 1 3 1 Before I begin with the s umm ary of the workshop result s, I wo uld lik e to relate an interesting observat i on made by many of u s at the works h ops: if we think about the curric ulum in the large blocks we u s ually use-thermodynamics transport 106 ) phenomena, kinetic s, etc. -then change will be difficult or imp ossib l e. The reason i s very simp l e The current curricu lum i s full ( or overflowing); if we take these large unit s to be givens in a new curriculum then there is s imply no room for new content. Hence we fe lt it worthwhile and important to put everything on the table and to s tart with a clean s late in thinking about the future We asked ourselves what s hould a Decade XI" box covering the years 2005 to 2015 look like if we were to ex t end the Hougen analysis? Principles The first va lu able le sso n to emerge from the workshops was a set of principl es that captured well the consensus of the gro up These included: l!l".I Changes in sc i e n ce and th e m a rk e tpla ce ca ll for ex t ens i ve c han ges t o th e c h e mi ca l e n g in eer in g c urri c ulum l!l".I Th e enabling sciences ar e: biolo gy, c h e mistr y, ph ys i cs, math e mati cs l!l".I Th e r e is a co r e se t of org ani z in g c h e mi c al e n g in ee rin g prin c ipl es M o l ecu lar transf o rmati o ns multis ca l e analysis, sys t e m s Molecular-level d es i gn is a new co r e o r ga ni z in g prin c ipl e l!l".I Chemical eng in ee ring conta ins b o th produ c t and pro ces s d es i gn l!l".I Th e r e is a g r ee m e nt on the ge n e ral attributes of a c h e mi c al e n g in ee r Two of these elements need elaboration: the core organiz ing principles and the attributes of a chemical engineer. Organizing principles In order to arrive at a picture of the curriculum we began by en um erati n g the conte ntrather than the label s -that c h emica l engineering grad u a t es sho uld understand and be ab l e to use By then l ooking at the linkages and interconnections among these content elements, thre e organizing principle s for the chemical engineering curriculum e merged. These are molecular transformations multiscale analysis, and s ystems analysis and synthesis At the heart of chemical engineering is the manipulation of molecules to produce de s ired processe s and product s. This is encompassed by the organizing principle of molecular trans formation s. Our students must recognize by both qualitative reasoning and quantitative computation that propertie s can be changed by changing s tructure. Molecular changes can be architectural for examp l e by forming or breaking cova lent bonds or by secondary or tertiary interactions to form s uperC h e mi ca l Engineering Education

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C structures. Or mole c ular changes can be conformational, for example in the orientation and stretching of polymer mol ecules to change mechanical properties or in the folding of proteins. Chemical engineers need to under s tand the equilib rium propertie s of the se molecular sys tem s and the rates of reaction or s tructural changes. Finall y our grad uat es s hould be equally comfortable with the manipul a tion of biological molecule s as with the s mall organic a nd larg e sy nthetic pol mer molecule s that have been the traditional domain of chemi cal engineering It i s not sufficient for chemical engineers to manipulate matter at the molecular level. In addition we mu s t be able to connect beha v ior at th e small sca le with that at the large scale. For example we need to be able to The Next Millennium in ChE ) entire globe or large regions of the globe in which we desire to regulate sources of emissions in order to control concen tration s of unde s irable chemical species. In summary, chemical engineers leverage knowledge of mo lecular processes across multiple-length scales in order to sy nthesize and manipulate complex systems comprising pro cesses and the products they produce. These new principles are summarized in Figure 3. Attributes Engineers are fundamentally problem solvers, seeking to achieve so me objective of design or performance among tech nical soc ial economic, regulatory and environmental cons traint s Chemical take the molecu lar-level under standing of the ki netics of a chemi cal reaction and use thi s to de s ign an appropriate re actor for commer c ial u s e Or we need to be able to exploit the under s tanding of poly mer conformation on properties in or der to de s ign a commercial s pinMolecular Scale Transformations engineers bring par ticular insights to problems in which the molecular na ture of matter is im portant. As educa tors we cannot teach students everything that might be en countered; instead we aim to equip graduates with a confident grasp of fundamentals and engineering tools, enabling them to Old core does chemical & biological physical: phase change adsorption etc Multi-Scale Descriptions not integrate molecular concepts from sub-molecular through super -ma cro Old core covers only macro to continuum, physical and chemical for physical chemical and biological processes Systems Analysis & Synthesis at all scales tools to address dynamics complexity uncertainty external factors Old core primarily tied to large scale chemical processes 1 1 Figure 3. New orga ni zing core principles for us e in integrating the c urri c ulum ning process to make high-strength fibers. The organizing prin ciple of multiscale analysis addresses the application of chem ical engineering principles over many sca les of length and time. It is not the goal of multiscale analysis to have s tudent s work from the atomic or molecular level up to the macroscopic level in every problem Rather it i s important that s tudent s develop the ability to recognize, in any given problem what the important length and tim e sc ale s are for analysis and de s ign Ultimately chem i ca l engineers cannot be s uccessful unles s we can take the knowledge of molecular processe s and the ability to manipulat e these across appropriate sca le s and in tegrate these into functional sys tem s The organizing prin ciple of systems analysis and synthesis deal s with the tool s for sy nthe sis, analysis, and de s ign of proce sses, units and combinations of these The sys tem s of importance to chemi cal engineers cover a range of sca le s. The y could b e single cells in which we manipulate and control metabolic pathways to produce de s ired chemical product s, or they could be the Spring 2006 specialize or diver sify as opportunity and initiative allow. We seek in our cur riculum to develop critical thinking and problem solving s kills especially for open-ended problems and those with noi sy data or uncertain parameters; to cultivate professional attributes including oral and written communications skills; to broaden the technical base of the stude nt s by including examples from a variety of indu s tries; and to cultivate an in stinct for lifelong learning and an awareness of the socia l impact s of engineering and technology. The need for agi l e, inquisitive, and fearless engineers is strongly reinforced in the M o l ec ular Fronti er report on chemical sciences and en gineering, 141 which points out that the cutting-edge knowl edge of chemical engineering practice across industries is changing constantly as are global networks of technology d eve lopment. In working to create a c urri culum for the future, it is our challenge to se t a national vi s ion for chemica l engineer ing grad uate practice beyond the norm, at the level de scribed by several national commissio n s on e ngineerin g 10 7

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( The Next Millennium in ChE ed u cation that e n vision e ngineering grad u a t es who are able to use fundamental knowledge of science a nd engi neering in a flexible and creative manner The Molecular Frontier report 14 J envisioned future graduates w h o can meet the following challenges: l!"".l Understand the basic c hemistry of traditional c hemical processes li ving systems, advanced mat e rials, and env i ronmenta l co ntrol l!"".l Synthesize and manufacture any new subs tan ce that can have scientific or practical interest using compac t synthetic schemes and proc esses with high se l ect i vity for the desired product and wi th l ow ene r gy consu mption and benign environmenta l effec t s l!"".l R evo luti onize design of c h em i ca l processes to make them safe co mpact flexible energy efficient, env ir onmentally benign, and co ndu c i ve t o the rapid co mmercialization of new produ c ts. l!"".l Understand and con t rol, to the limit s of c urrent knowledge and t oo l s, how mole c ules r eact over all time scales and th e fu ll range of molecu l a r si z e. I!"".] Develop unlimit ed and in expens i ve energy, with new ways of energy generation s t orage, and transporta tion to pave the way t o a truly s u sta inabl e future. l!"".l Communicate effective l y to the genera l publi c the co ntributions that c hemi c al e ngineering makes to society l!"".l B e able to work in an interdisciplinary team of scientists, enginee r s, a nd produ c tion p e r sonne l to brin g new substances from lab to production to market A Dr a ft Curriculum Freshman ) a curricu lum to present ; we are not yet that far along. At th e third workshop held on Cape Cod, however we developed a draft curriculum as a proof of concept" to convince our se lve s that thi s was po ss ible. Shown in Figure 4 is the layout for a curriculum that develop s the three organizing prin c iple smolecular tran sfo rmation s, multiscale analysis and sys tem s analysis and sy nthe sisin parallel throughout the undergraduate years and s how s how the three themes are integrated in chemical engineering practice The content mu s t also b e integrated horizontally throu g h time, so that each principle i s clearly developed. It is impor tant to provide many opportunities for repetition of key idea s, concepts, and tools as the s tud e nt s move through the four years of curriculum. The reinforcement of these k ey elements s hould also be accompanied by a sys tematic movement from s imple to complex topic s as the curriculum proceed s Content mu st also be integrated vertically at g i ve n time s in order to avoid compartmentalization. On e way to achieve thi s vertical int egra tion i s to u se part of each year for case s tudie s, projects, or l a boratorie s that cut across th e three theme s. For example each theme in the core curriculum cou ld b e pre se nted in one-and-a-half-semes t e r s ubjects. In the latter half of the s pring se me ste r each year, students could work in teams on intensive integrated laboratory or de sig n project s that enable them to take the ma teria l l earned that yea r and apply it in projects developed by indu s try/academic proje ct m e mb e r s In thi s way, both the t eac hing and learnin g of the integrated core would b e ad dre sse d. Integration co uld be further enhanced by a s mall group seminar series ( po ss ibl y a ppended to an existing s ub ject ) that develop s important abilities of social awa rene ss, Soph Junior Senior I Molecular-Scale Transformations The curriculum must engage s tu d e nt s in the s ubject matter of chemi ca l engineering and its u se, and culti vate along the way that mix of a tribute s that characterizes the engineer. To accomplish these goals we envision a four-year s tructure that emphasizes th e theme s of c hemical engineering, in tegrate s the contents of these themes into a flexible and strong under s tand ing, and exercises the skills we want to develop. Thi s structure is versatile admitting a variety of material s and modes of presentation, and i s thu s adaptab l e to a rang e of cultures, r so urce s, and faci liti es found among chemical engineering department s. Enabling Courses Molecular Basis Molecular Basis of Rea ctions Special Topics of Thermo Molecular Basis of Properties {Electives) Physics Classfctn of Molecules and Constitutive Eans Chemistry I D Biology Math Multi-Scale Analysis Beaker to Plant: Mat'ls Sci Interfaces and Assemblies Multi-Scale Descriptions Principles of Product & Eng/Comm Homogeneous Reactor Eng of Reactive Systems Process Des. Bus/Mgt I D Systems Systems & Chem Eng : Intro to Systems Intro to Molecular Systems The Marketplace The Frosh Experience I I do not h ave a fini s hed structure of Figure 4. An exa mpl e la you t of a c urri c ulum. /08 Chem i ca l Engineering Ed u c ation

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C professional ethics, communication, business development and professional practice, and economics. By focusing each seminar series on these important nontechnical abilities, stu dents would hone these skills and be better able to apply them as part of their spring semester integrated project work. In summary, the material within an academic term as well as across the four years, must proceed from si mple to com plex. Fundamentals must be illustrated with applications, and examples must range from the si mpl e demonstration to the challenge of complex design or sys tem manipulation. Finally, students must be engaged actively with thi s material. At the end, the curriculum must add up to a complete picture of chemical engineering. The detail given in each principle block suggests an order of topics. Detailed definition of these blocks is the subject of ongoing workshops. CONC L UDING REMAR KS This paper proposes a vision for chemical engineering edu cation for the future-for 2015 and beyond. To return to the Hougen analysis of the chemical engineering curriculum shown in Figure 1, I am suggesting a s tructure and focus for Decade XI as illustrated in Figure 5. Becau se we have not engaged in substantial curriculum revision in 45 years, I be lieve that we are best served by beginning with a clean slate. For outflow, I suggest the entire current curriculum. This is not to say that there are not key elements of what we teach today that s hould be retained but rather everything in the existing curriculum must compete with new idea s to win a s pot in the new curriculum. As illustrated in the figure, the Decade XI curriculum would be organized around the orga nizing principles of molecular tran sfo rmations multiscale analysis, and systems analysis and synthesis. >, Ol 0 0 ii ~ (/) ;;; <1l .c ~ Ql .;:::, Ol C Ol cn .ffi <1l C Ql u -g E"' l Molecular engineering Systems analysis ri Biology Y Product PRINCIPAL DEVELOPMENTS DECADE XI Molecular transformations Multi-scale ana l ysis Systems view The Next Millennium in ChE ) This radically different curriculum would produce more versatile chemical engineers, who are needed to meet the chal lenges and opportunities of creating products and processes, manipulating complex systems, and managing technical op erations in industries increasingly reliant on molecular unThe opportunities f o r reform in chemical engineering curricula are so compelling and broad that an appropriate response req u ires wide-ranging pa rticip a t io n across the entire d isci plin e. derstanding and manipulation. Another benefit of the new curriculum is that it reconnects undergraduate education with ongoing re searc h in chemical engineering in a way that has not been pre se nt for the past 40 years. This reconnection will serve u s well as an engineering discipline in attracting the best and brighte s t s tudent s and in reopening the path to con tinual renewal of the curriculum. ACKNOWLEDGMENTS In writing this paper I have drawn very heavily on the col lective thinking at the Frontiers Workshop s. It is impossible to e mpha s ize too s trongly how much we have to learn from one another as we move forward in this great adventure. I want to give special thanks to the participants who synthe size d s ummary reports at each of these workshops-Nick Abbott, Jeff Reimer Jim Rawling s, Mike Thien Greg McRae, and Bill Green-and to Barry Johnston who pre pared all of the material for the Frontiers Web site including the excellent executive summaries. Finally I thank Jeannette Gerzon who has ably helped or ganize and facilitate these workshops to help us OUTFLOW be productive. ? REFERENCES 1 AIChE Career Services, Initi a l Placement Survey. Data s hown are from 2003; sim ilar data for 2002 are accessible at (2003) 2. Hougen O.A., "Seven decades of chemical engineering," Chem. Eng. Pra g. (1977) 3. Proceeding s of CCR/NSF Workshops on Frontiers in Chemical Engineering Education, < http :// mit.edu /c he-cur riculum/> (2003, 2005) Figure 5. The propos ed extension to Haugen 's chart. 4. NRC, National Res earc h Council, Board on Chemical Sci ences and Technology, Beyond rh e M o l ec ular Fromier, Challenges/or Chemisrry and Chemica l Engineering, Na tional Academies Pre ss (2003) 0 Spring 2006 109

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( The Next Millennium in ChE ) TEACHING ENGINEERING IN THE 21 57 CENTURY WITH A 12TH-CENTURY TEACHING MODEL: HOW BRIGHT IS THAT? RICHARD M. FELDER North Carolina State University Raleigh NC 27695-7905 I f you took a stroll down a hall of the University of Bolo gna in the 12th century and looked into random door ways, you would have seen profe ss ors holding forth in Latin to rooms full of bored-looking s tudents. The profes s ors would be droning on interminably in language few of the s tudents could understand perhap s occasionally asking que s tion s, getting no response s, and providing the answer s themselve s. You might see a few s tudent s jotting down note s on recycled parchment a few mor e s neaking occasional bites of the cold pizza s lices concealed in their academic robes so m e s leeping, and most just s tarin g vacantly, inwardly curs ing the fact that iPods would not become readily available for another 800 years. Toward th e e nd of the lecture one stu dent would ask Professore siamo r es ponabili per tutta questa roba nell 'esa me? and that would be the only active student involvement in the class. Eventually the class would be re lea se d and the students wou l d leave grumbling to each other about the 150 pages of reading assigned for the next pe riod and ex pressing gratitude for th e CliffsNote s version of the text. American engineering education doe s n t exact l y follow that model. For one thing the only e ngineering profes so r in the We s tern Hemisphere-and maybe in the world-who could lecture in Latin wa s Rutherford Ari s, and he 's decea se d. Hard drive s have replaced parchment basebal l caps and jeans have replaced caps and gowns, and ( thi s i s a huge difference ) s tu dents in Bologna actually had a lot of power including the responsibility of hiring professors and the right to fire them if their performance was considered un sa tisfactory. Leaving tho se differences aside, however the fact i s that thing s haven t changed all that much s ince the 12th century. If you walk down the hall of an e arly 21st-century engineering sc hool and look into random doorway s, th e re 's a goo d chance you II see the de sce ndant s of tho se Bologn es i s tarin g vacantly, Richard M Felder is Hoechst Celanese Professor Emeritus of Chemi cal Engineering at North Carolina State University He received his B ChE. from City College of CUNY and h is Ph.D from Pr i nceton He is coauthor of the text Elementary Principles of Chemical Processes ( Wiley, 2005) and codirector of the ASEE National Effective Teach ing Institute Copyright ChE Division of ASEE 2006 110 C h e mi c al E n g in ee ri ng Ed u c ati o n

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C snacking, and sleeping as their profe sso rs drone on inces santly in what might as well be Latin and fill t h e board or projector screen with Latin and Greek sy mbo l s that have little or no obvious relevance to anything the students know or care about. Twenty years ago that 's all yo u would have see n in those classrooms, with very few exceptions. Now, however in some departments at so me schools yo u can find a significant num ber of classrooms in which other thin gs are happening You might get the first signal of a difference before you ever get to the doorway when from down the hall you hear thing s that are never heard in a traditional engineering classroom so und s of conversation, di sc u ssio n and arguThe Next Millennium in ChE ) only occur when the students had established a need to know something to progress with their work So why the change? What is the answer to the traditiona l professor 's traditional defense of tradition: It 's been done thi s way for decades or centuries and ha s worked fine," or implicitly "T hi s i s how I was taught, and look how well / turned out!" Ther e are several answers, w hich would take much l onger to present completely than I have in this little piece so I'll only give brief suggestions of what they are and po i nt to ref erences where the who l e story can be found. First if "wo rkment possibly punctuated by laughter alter nating with periods of si l ence. If you look into the room for awhile you would see traditional classroom moments alternating with brief pe riods in which students are doing thin gs indi vidually or in pairs or small groups-answer in g questions, completing the next s tep s of derivations or problem solutions, troubl es hoot ing predicting estimating, critiquing, inter preting, modeling de s ignin g, formulating questions, and su mmarizin g At any g i ve n mo m e nt the profe ssor might be in front of the class lecturing and answering que s tion s, or quietly observing the activity, or wandering around the room interacting with individual st udent s and student groups. Unlike the s ituation in the traditional classroom, many people-includ ing the professor-would appear to be enjoy If y ou have been firml y entrenched in the ing fine means turning out excellent engineers who have made brilliant creative contributions to indu s try and soc iety, that has certainly happened over the centuries The issue however is whether it happen ed because of traditional higher education or despite it. There is compelling evi dence that the latter may be the case. Take Eu rope, for exa mple In the traditional European system of higher education that has prevailed for centuries, the profe sso r is a god l ike figure who lecture s to s tudent s and has little or nothing more to do with them Th e st udents may or may not choose to attend the lectures-if the professor i s a particu l arly sk illed lecturer they attend other wise mo s t don t. traditional paradigm I would encourage y ou to try branching out but I would also suggest taking it easy. You might argue that thi s sys tem led to the wondrous scie ntific advances of the Renaissance and the En l ig h tenment and the giant tec h no l ogiing themselves. Also unlike the traditional classroom most of the st udent s enrolled in the course would actually be the r e. If you inquired fur t her into how courses are run in that de partment you would see further evidence of two competing model s -one that would see m familiar to our 12th-century scholars and one dramatically different. In one set of co u rses, the professor would spend a great deal of class time lecturing on the ba s ic facts formulas and problemso lving algorithms that comprise the course material, and would then give as signments and tests calling on t h e s tudents to demonstrate their ability to recite t h e facts, execute the formulas, and imp l ment the algorithms. In the other courses, the students would be presented with problem s before they are told everything they need to know to determine the so lution s. They wo u ld then work-sometimes individually and sometimes in team s -to identify what the y know a nd what the y need to find out do re searc h, formulate and te s t hypothese s, and ar rive at so l utions The profe sso r would s till be there to pro v i de informat i on and g u idance, b u t forma l i n struction wo ul d Sprin g 2006 cal leap s of the industrial revol u tion but I wou l d quarrel with that argument. If you admit only the cream of the crop of a nation 's youth (w hich univer s ities in Europe and America did unti l fairly recently) it almost doesn t mat ter what yo u do or don t do in the classroom. You could sim ply hand out syllabi and li s t s of references and tell the s tu dents that they will be examined at the end of the year, and then do nothing else-no l ectures, no homework no tests except the final exam-and mo st s tudents would manage to learn the material and pass the exam, and the few geniuses among them would go on to m a ke their brilliant contribu tio n s, espec i a ll y i f t h ey were clever eno u g h to apprentice them se lves to master s from t h e previous generation. In s hort professor s who provide only traditional lecture based instruction are large l y irrelevant to t h e rea l learning proce ss for top students. Good lect u rers can certain l y enrich their classroom experience, but they will learn with or with out that enrichment. On the other hand if you are trying to educate a broad segment of the pop ul at i on-as we are now doi n g i n t h e Uni t ed S t ates-many students can't make it with 111

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( The Next Millennium in ChE only the support that traditional instruction provides and the consequence is the attrition of 50 % and higher that we rou tinely see in engineering. Another argument for change i s that unlike our anteced ents in the Middle Ages, we now know a lot from cognition re searc h about how people learn and the instructional condi tions that facilitate learning [ see the reference by Bransford et al. in the bibliography], and everything we know s upports the proposition that the traditional lecture-homework-test paradigm of engineering education is simply ineffective good students learn despite it, and weaker students who could make excellent engineers frequently cannot survive it. The alternative instructional environment supported by the re search is quite different. Here are some of the things teachers do in that environment, contrasted with what they do in the traditional approach. 112 T: ( Traditional) Establish a syllabus assuming that all necessary prerequisite knowledge is known, and march through it. A: ( Alternative) Find out at the beginning of a course what most of the students know and don't know and what misconceptions they have about the subject, and start teaching from that point. (This approach is known as constructivist teaching.) T: Assume all students with the ability to succeed in the profes sio n for which they are being educated are basically alike (specifically, like the professor) and learn in the same way, and teach accordingly. A: Recognize that good students vary consider ably in motivation, cultural background, inter ests, and learning style, and teach accordingly. T: Focus on facts formulas, and algorithms for solving well-structured closed-ended single discipline problems. A: Supplement the traditional content with training in critical and creative thinking meth ods of solving ill-structured open-ended multi disciplinary problems (which tend to be what practicing engineers s pend most of their time dealing with), and professional skills such as communication, teamwork and project manage ment. T: Cover basic knowledge (facts, algorithms, and theories) in lectures, then assign problems that call for implementation of the knowledge, then illustrate the knowledge in l aboratories. ) A: Recognize that s tudent s learn best when they perceive a need to know the material being taught. Start with realistic complex problems let s tudents establish what they know and what they need to find out, and then guide them in finding it out by providing a combination of resources (w hich may include mini-lectures and integrated hands-on or simulated experiments) and guid ance on performing library and Internet research This is indu ctive teaching and has a number of variations, including problem-based l ea rnin g pr oject -bas ed l earning guided inquiry, discovery l earning, and just-in-time teaching. T: In clas s, present information derive formulas, and illustrate problemso lving procedures in lectures, boardwork and overheads or PowerPoint images, occasionally asking question s and responding to questions stu dents might ask. A: In addition to lecturing have students work individually and in small groups on brief course related activities such as answering questions setting up problem solutions, completing steps in derivations, interpretin g observations or experi mental data estimating predicting brainstorm ing, trouble s hooting .. Call on several students for response s at the conclusion of each activity, then invite volunteers to provide more responses to open-ended questions, and proceed with the lesson when the desired points have been made. This is active l earn ing. T: Require st udent s to do all of their work individually. A: Assign a combination of individual work and teamwork, s tructuring the latter to provide assurances of individual accountability for all the work done and following other procedures known to promote good teamwork skills (including communication, leadership, project management, time management and conflict resolution skills) Thi s is coo perativ e learnin g. T: Tell the st udent s they are re s ponsible for everything in the text lectures and homework, and make up exams that draw on those sources, including some problems with twists that the Chemical Engineering Edu c ation

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C students have not seen before and have to figure out on the spot. (Those problems are there to see if the s tudents "k now how to think. ") It is up to the students to guess what the instructor think s is important enough to include on a test. A: Write comprehensive instructional objectiv e s that list the thing s the s tudent s should be able to do (identify explain, calculate, model design critique ... ) to demon s trate that they have sa tisfactorily ma s tered the knowledge and skills the instructor wants them to master including high-level thinking and problem-solving skills. Make the objectives available to the students, ideally in the form of study guides for te sts. De s ign in-clas s activities and homework to provide practice in the desired skills and make the test s spec ific instances of a s ubset of the in s tructional objectives. Instructor s who are unfamiliar with the latter approach imagine that they will have to list thousands of objectives to be comprehensive, but thi s i s not the case-a twosi ded sheet of paper i s normally s ufficient to list all of the ob jective s that might be drawn upon to co nstruct a midsemester te st. Entire articles and book s can be-and have been-written on each of the given alternative teaching methods, de scr ib ing how to implement them and summarizing the research base that demonstrates their s uperiority to the traditional ap proach The bibliography at the conclusion of this paper sug gests starting point s for intere s ted readers. If you have been firm l y entrenched in the traditional para digm I would encourage you to try branching out, but I would also suggest taking it easy. Going directly from a traditional teaching model to a full-bore active/cooperative/problem based learning paradigm s tartin g ne xt Monday is probabl y not a good idea-the amount of preparation required and the student re s istance that might erupt could be overwhelming. A better approach is to make the c hange gradually perhap s by doing a few small-group exercises in lecture s, u s ing a problem-ba se d a pproach to teach one or two topic s, and writing instructional objectives for one midterm t es t In s ubsequent courses, increase you r u se of the new meth ods never departing too much from your comfort zone and you s hould see your students learning steadily increa s ing. After all it took u s 800 yea r s to get from Bologna to where we are now; if it take s yo u a few years to get where you want to be the sky won t fall. Spring 2006 The Next Millennium in ChE) BIBLIOGRAPHY Effect i ve Teach i ng Methods and t he Research that Supports Them I Bran s ford J D ., A L. Brown and R.R Cocking eds. H ow P eo pl e L e arn : Brain, Mind Exp e ri ence, and School Wash ington DC : National Academy Pre ss, 2000 Online at < http: // www .n ap.edu / html l h ow p eo pl e l /> 2. Felder R.M D.R. Woods J E. Stice, a nd A. Rugarcia The Future of Engineering Education: 2. T eac hin g Methods that Work ," Chem. En g. Ed., 34(1 ), 26-39 (20 00 ) Online at 3. Woods D R ., R M. Felder A. Rugarcia and J E Stice The Future of Engineering Education: 3. Developing Cr i tical Skills ," Chem. En g. Ed 34 (2), 108-117 (2000) Online at < http: I I www.ncsu .e du l f e ld e r-publi c/ P apers l Q uartet3 .pdf> Act i ve Learning 4. Felder R .M., Random Thoughts columns in Chemical En g in ee rin g Education: (a) Learning b y Doing ," < http: // www .n cs u edu / felder publi c/ Co lumn s / Acti ve .pdf> ( b ) It Goe s Without Sa y ing ," < http :// www .n c su. e du / fe/der-publi c/ Columns / WithoutSa y in g .pdf> See a l s o < h11p : !! www .n cs u. e du/felder-publi cl Cooperative_ L ea rnin g. html> 5. Prince M. "Does Active Learning Work ? A Review of the Research ," J. Engr. Ed 93 (3), 223-231 (2 004 ) Coope r at i ve Learning 6. Felder R M ., and R. Brent, Cooperative L e arnin g in T ec hni ca l Cours es: Pr oce dur es, Pit falls, and Pa yo ff s, < http :// www.ncsu e du / f e ld er -pub/ i cl Pap e r s / Co o preport html>. See a I s o < h II p : I I w w w n cs u e du I f elde r publi c I C oo p e rati ve_ L e arnin g. html> 7. Two meta-anal yses of r esea rch on cooperative learning vs. tra ditiona l in s truction can be found at < hllp : ll www.co-opera t ion.o r g/> (U niversity of Minnesota) and < http ://w ww. w ee r w is e .e du l nis e / c ll / CL/resourc e/ R2 ./um > ( University of Wi sc on s in ) 8. A Web s it e wit h link s t o CL-related papers and many CL s ites i s Ted Panitz 's < http : // h o me. c ap eco d net / -tpanit z/> Problem Based Learn i ng 9. Prince M.J. and R.M Felder "Inductive Teaching and Learn ing Method s : Definition s Comparisons and R ese arch Ba ses J. Engr. Ed in pre ss (2 006 ) 10 Duch B.J. S.E Groh an d D .E. Allen Th e Po we r of Pr o bl em Ba sed L ea rnin g, Sterling VA: Stylus (2 001 ) 11 Universi t y of Delawar e Probl e m-Ba sed Learning Clearing hou se, < hllps : //c hi co. nss.ud e / .e du / Pbl />. Ted Panitz 's site ( < http: // home. ca p eco d n et / -tpanit z/ >) and D e lib era tions a site managed by London Metropolitan University () ar e good so ur ces of both information about PBL and links to oth e r PBL-related s it es. 0 113

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( The Next Millennium in ChE ) A DIFFERENT CHEMICAL INDUSTRY E.L. CUSSLER University of Minnesota Minneapolis, MN 55455 A n Altered Industry. The chemical industry today i s completely different from the chemical industry of 25 years ago. The clearest evidence comes from the jobs taken by g raduating chemical engineers. Twenty-five years ago, 80 percent of the se graduating students went to the commodity chemical indu s try exemplified by Dupont, Exxon, Shell and Dow. Occa s ionally they went to interna tional companies such as Bayer and ICI, though this was le ss common. The remaining 20 percent were roughly divided into equal g roups. Some perhaps IO percent went to prod uct-orient e d bu s inesses s uch as PPG Up john or 3M. A s imi lar number, perhap s another 10 percent went to everything else, including consulting, government, and academia. This older chemical industry, dominated by large-commodity chemical companies, was very fami l iar and dependable. Today as Figure I s hows, the situation is completely dif ferent. The percentage of graduates going to the commodity chemical companies has dropped dramatica ll y, perhaps to a quarter of the total. Simultaneously, the percentage going to consulting has risen to around another quarter. This consu l ing include s functions such as process engineering, now con tracted out rather than performed within the engineering labo ratories of the commodity chemical companies. The bulk of new graduates, however now goes to indus tries where product s are mo s t important. Some of these prod ucts such as pharmaceutical s, are familiar; others, such as foods, have existed previou s ly but have not involved signifi cant number s of chemica l engineers; still others such as elec tronics represent new efforts. WHAT PRODUCTS ARE IMPORTANT In this altered chemical industry, we must first ask what are the product s that we are going to produce I believe there are three types of the se products, each with different charac teristic s The fir s t and mo s t obvious are the familiar comll4 moditie sthe sa me products which u se d to dominate the chemical engineering enterprise. The key for producing the se new products is their cost. Styrene produced by Dow and styrene produced by BASF are chemically identical ; the is s ue i s who can produce large quantities at the lowe s t possible price. The second and third type s of product s may be les s famil iar. The sec ond type involves molecules with molecular weights of 500700 and with s pecific soc ial benefit s The mo s t ob v iou s examples are pharmaceutical s The key to the pro duction of pharmaceutical s i s not their cost but rather their time to market, i.e., the s peed of their di scove ry and produc tion The first-to-market tends to get at least two-thirds of the eventual sales for the molecule, even after patents on the par ticular molecule expire These products are normally not made in dedicated equipment but rather in whatever reactors are ava i lab l e at that specific time Thus, process optimizations tend to be less important than questions of scheduling: If the equipment is being used for many different produ c t s, when can you get in to mak e yours? The third product type includes those for which the value is added by processing to make a specific nanostructure. The key to these product s i s their function. For examp l e, I don t Ed war d L. Cuss /er currently distinguished institute professor at the Univers ity of Minnesota received the B.E. with honors from Yale University in 1961 and his M.S and Ph.D. in chemical engineering from the University of Wisconsin i n 1963 and 1965 respectively. Soon after he went to teach in the Department of Chemical Engi neering at Carnegie Mellon University. In 1980 Gussler joined the faculty at the Uni ve rsity of Minnesota. He is the author of Multicom ponent Diffusion published in 1976 and D iff usion published in 1984 with a second edition published in 1997 He is the co-author of Membrane Separation Systems Bioseparations and most recently, Chemical Product Design the English edition of which was published in 2001. Copy ri ght C h E D i v i s i o n of ASEE 20 0 6 C h em i cal E n gineering Ed 1.1 c ari o 11

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C care why my shoes shine after I have applied polish ; I only care that they do shine. It is the shine, not the molecule that produces the shine, that is important. Customers are often willing to pay a premium for such a function be it in a coat ing in a food, or in a cleaner I find it helpful to think about these three types of products using the summary shown in Table I. For commodity prod ucts the key factor as stated previously is the cost of the prod uct. The basis for producing the product will continue to be unit operations-unit ops-the familiar core of chemical en gineering. Our action in this area should be to sustain the commodity industry. We are certainly not currently carrying out unit operations in the best way possible, but we are prob ably close to the limit of what is economically attractive. With the key factor of the second type of molecular prod ucts being time to market, the major cost of products of this type such as drugs, is not the proces s engineering but the cost of their discovery. At best only one in a thousand drug candidates is commercially successful. This enormous drop out rate is the reason drugs are expensive. The key to discov ery normally comes from chemistry and microbiology, not from chemical engineering. As a result, it is not clear whether traditional process engineering has a major role to play in molecular products. For nanostructured products the third type whose key fac tor comes from their superior function the added value comes from the process rather than from the chemical synthesis. Their desired function is the shine of the polish or the clean ing of the detergent. Studies in this area seem to lack any unifying intellectual core. Flavor release in food science takes no advantage of what is known about controlled drug release in pharmaceutics Micelle formation in latex paint is an inde pendent topic from micelle formation in detergents I believe there is a genuine need for a general theory of nanostructured products. Such a theory could be part of a required course common to departments including chemical engineering, food science and pharmacy. IMPLICATIONS FOR EDUCATION Faced with this a l tered chemical industry, we must ask whether the skill set currently mastered by chemical engi neers is appropriate for the future. This skill set consists of three roughly equal parts, based in physics and mechanics in chemistry and biology, and in chemical engineering. I don't think this skill set is inappropriate for the future. The ideas of reaction engineering and separation processes will continue to be central to what chemical engineers do Within these areas some topics will recede and other topics will become more important, but the core will remain Sprin g 2006 The Next Millennium in ChE ) Where the Job s Are Commodities Products D Consult Figure 1. Wh e re the jobs are in chemi c al engineering. I do think that there may be a partial problem with the courses that present these topics. At the moment, these courses are biased heavily toward the commodity chemical industry. This bias includes such classical chemical engineering courses as transport phenomena and thermodynamics. In the future, new courses including those based on biology, on polymer science, and on product design must become more central to the chemical engineering curriculum. We require three such courses at the University of Minnesota precisely because we believe the content of those courses will better prepare our students for the new chemical industry. Some may find this description of a changed chemical in dustry depressing. I don t. I think it is simply different. For example, it means that we may now work more on crystalli zation and less on fugacity, but I don't think that is a prob lem. In many ways, the reemergence of an emphasis on prod ucts and the corresponding de-emphasis of a few commodity chemicals suggests a broader intellectual challenge for chemi cal engineering That challenge is interesting. I welcome it. I think it is exciting. And I think all of us will discover that excitement together. 0 TABLE 1 Three Kinds of Products Diff e r e nt s trat e gi es a r e appropri a t e for diff e r e nt kind s of products. Commodities Molecules Nanostructures Key Co s t Sp ee d Function Basis Unit Op s Di sc ov e ry f ( Prop e rtie s) Action Sustain Chemi s tr y Key Unified Theory 115

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( The Next Millennium in ChE CRYSTAL ENGINEERING : From Molecules To Products Preamble According to many contemporary scientists, engineers, policy-makers, and business l eaders, the future belongs to biotechnology, nanotechnolog y, and information te c hnol ogy. Chemical engineering research and teaching are being changed by these fields, as dis cussed in this series of articles and e lsewh e r e Change is happ ening at a measured pace, and biology ha s joined chemistry, physics, and mathematics as a fourth foundation discipline of the chemical enginee rin g curriculum. I ha ve littl e to offer that has not already been said about bio, nano, and info. How ever, there are other sub je cts that are of vita l int erest to society that are squarely in the domain of c h em i ca l e ngine e rin g and that ha ve r eceived l ess attention than their wort h. Among these, ene r gy and c r ys tallin e so lids rank high. I would lik e to say some thin g about both these topics but I will co nfin e myself t o crysta llin e so lid s-pa rti cu larl y organ i c materials. My goal is to highlight the importance of the so lid state and to show how easi l y it can be in co rporated into the c h emical engineering curricu lum. MICHAEL F. DOHERTY University of California Santa Barbara, CA 93106-5080 ) C ry s talline organic so lids are ubiquitous as either fi nal products or as intermediate s in the specialty chemical pharmaceutical and home and personal care industries. Virtually all s mall molecular-weight drugs are isolated as crystalline materials 1 1 1 and more than 90 % of a ll pharmaceutical products are formulated in particulate, gen erally crystalline, formP 1 Crystalline chemical intermediates s uch as adipic acid a re produced in large amounts to make polymer s and specialty product s. Skin c ream s and other per so nal-care product formulations contain crystalline solids. In most case s the properties of the crystalline so lid have a ma jor impact on the functionality of the product as well as the design and operation of the manufacturing proce ss ibility (important for tabletting), and s tability. The crystal enantiomorph is of vital importanc e in the manufactur e of chira l material s, which ha s become a $ 150 billion industry in recent years. The choice of so lvent, along with the design and operation of the manufacturing process determines the crystal properties. Moreover crystal s ize distribution and shape hav e a major impact on the design of the manufactur ing proce ss s ince s mall crystals are difficult to separate from solution, and needle-like crystals or plate-like crystals can be difficult to filter and dry Crystal s ize (or size distribution ), s hape enantiomorph, and polymorph all influence product functionality. For example, even a 50 micron particle in a hand cream makes the cream feel gritty 1 31 Size di st ribution is important in the manufacture of beta-carotene which i s virtually in so luble in water and only sparingly soluble in vegetable oils, and is used as a food colorant. The color shade given to the food is determined by the narrow size distribution which mu s t be in the submicron range.13 1 Cr ys tal s hape and polymorph influence solubility, disso luti on rate ( which influences bioavailability) compress// 6 Michael F. Doherty is a professor of chemical engineering at the Univer sity of California Santa Barbara He received his B Sc. in chemical engi neering from Imperial College University of London in 19 73, and his Ph.D. in chemical engineering from Trinity College University of Cambridge in 1977. His research interests are in process design together with the asso ciated chemical sciences necessary to support the design activity He has published extensively on design and synthesis of nonideal separation sys tems especially the coupling of separation with simultaneous chemical reaction and crystallization of organic materials from solution He is the holder of four patents has published more than 150 technical papers and one textbook and has delivered more than 180 invite d lectures He has served as a consultant for many multinational companies in the area of process design and separations technology, and has served on the Cor porate Technical Ad vis ory Boards for The Dow Chemical Company and Rhone Poulen c. Copyr i g ht ChE Divi s ion of ASEE 2006 Chemi c al Engineering Ed 11 ca ri o 11

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C Many important compounds exhibit polymorphism i. e the existence of more than one crystal structure Different poly morphs can have very different physical properties includ ing color, hardness and stability Therefore control of which polymorph crystallizes in an industrial s ystem is of vital im portance. For example, since bioavailability can vary greatly among po l ymorphs of the same drug, 1 41 the U.S Food and Drug Administration requires the registration of each drug polymorph and the strict production of only that form. It can be difficult to control which polymorph crystallizes, even to the extent that production output can change unexpectedly from one form to another. This can be catastrophic, e g., halt ing production until the process can be altered to produce the original polymorph .'5 1 Many in industry particularly the phar maceutical industry, are now undertaking exhaustive poly morph screening to identify all possible/likely polymorphs before beginning to scale up crystallization processes. 16 1 The importance of crystal shape to processing and product quality/functionality has been discus s ed in the context of ibuprofen 1 7 1 The primary intere s t in thi s s ystem is the exist ence of high-aspect ratio needle s when grown from non polar hydrocarbon solvents such as hexane or heptane E qu a nt (i.e., low aspect ratio crystals with roughly equal sides) are formed when grown from polar solvents such as methanol or etha nol. This was discovered by researchers at the Upjohn Com pany, 171 who patented the change in solvent as a process im provement. The structure of this article is as follows. It begins by high lighting some of the advances made in the fundamentals of crystallization during the last decade together with recom mendations for where these topics can be inserted into the curricu l um. Next is a brief review of recent improvements in CFD and population balance mode l ing for crystallizers. Third are descriptions of new methods for process synthesis offlow sheets containing crystallization steps. Last are some recom mendations for incorporating crystal engineering into the core of chemical engineering education and research FUNDAMENTALS OF CRYSTAL ENGINEERING Crystal Structure A crystal is an ordered three-dimensional array of mol ecules, and represents one of nature s most remarkable ex amples of self-assembly. This definition contains the con cept of periodicity A solid material that has disordered struc ture or that displays no long-range order (although it may possess short-range order) is called amorphous. All crysta l s have translationa l symmetry, i.e. repetition of motifs by translational displacement in space. Each crystal can be decomposed into a collection of unit cells, which are the smallest structural units that re-create the entire threeSpring 2006 The Next Millennium in ChE) A cr y stal is an ordered three-dimensional arra y of molecules and represents one of nature s most remarkable e x amples of self-assembl y dimensional crystal structure when they are repeated in space by simple translation in every direction. Unit cells are paral lelepipeds, the vertices of which constitute a grid of points called a lattice with its own periodicity and symmetry. The unit cell also defines three sets of planes in space, each set being parallel and equally spaced-the distance between the plane s in each set i s called the interp l anar spacing, which is an important concept in crystal growth models Within the cell s ymmetry operation s relate the molecules that consti tute the contents of the cell. An asymmetric unit is the small est structural unit ( e g., a nonsymmetrical dimer, a single mo l ecule or part of a molecule) within which no symmetry ele ments operate. The collection of symmetry elements belong ing to a crystal structure is called a space group. Therefore, a space group is the set of geometrical symmetry operations that brings a three-dimensional periodic crystal into itself. There are a total of 230 unique space groups. The number of symmetry element s in a space group must be equal to the number of asymmetric units in the cell. It is important to realize that unit cells do not physically exist in a lattice and the lattice does not physically exist in the solid. These are mental constructs to help visualize the solid structure. There are several different lattice arrangements and unit cells that can be constructed-but only 14 possible lattices that fill three-dimensional space. These lattices can be further divided into seven crystal systems; each has a fixed relationship between the cell's spatial dimensions and angles. The seven systems are: cubic, tetragonal, orthorhombic hex agonal trigonal, monoclinic and triclinic. Most organic mol ecules have uneven molecular shape that leads to low-sym metry crystal systems. The crystallographic systems with uneven unit-cell parameters are the monoclinic, triclinic, and orthorhombic. The majority of organic structures reported (ap proximately 95 % ) belong to these systems. Molecules arrange themselves in crystals in such a way that the whole spatial arrangement must belong to one of the 14 Bravais lattices. The total number of independent ways in which molecules can decorate these lattices is 230 ( corre sponding to the total number of independent space groups). 117

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( The Next Millennium in ChE Fortunately only a few of these space groups are important in solid state chemistry. A more in-depth view of crystallog raphy is available from many sources, including Cullity,f 8 1 Stout and Jensen, 1 91 and the International Tables for X-Ray Crystallography. Crystal structure and x-ray crystallography are well suited for inclusion in the undergraduate physical chemistry se quence Gavezzotti 1101 has created an excellent visual intro duction to crystal symmetry, written in a tutorial style suit able for undergraduates. Nucleation Crystals are born by nucleation, which may be defined as the formation of molecular solute clusters in solution that are in dynamic contact with the solute molecules dissolved in the solution. When the clusters reach a critical viable size they become a crystalline particle that grows by the addition of solute material on the crystal faces. Faces may appear or disappear during growth depending on the relative growth velocities of adjacent faces. Nucleation can be divided into two types : primary and sec ondary. Primary nucleation is the formation of nuclei in solu tion whether or not suspended crystals are present. It is fur ther subdivided into homogeneous and heterogeneous. Ho mogeneous nucleation is the formation of nuclei in previ ously crystal-free solution. Primary heterogeneous nucleation requires the preexistence of foreign bodies or catalytic sur faces in the solution. Foreign bodies can be dust particles, nuclei of substances different from the solute etc. Catalytic surfaces may be roughness on the vessel walls, or a surface that was designed specifically for this purpose, such as a com pressed surfactant monolayer (Langmuir) film or a self-as sembled monolayer Secondary nucleation is used to describe any nucleation mechanism that requires the presence of sus pended solute crystals Secondary nucleation may take place by several mechanisms: seeding, breakage, attrition due to collision (collision nucleation), or removal of surface layers through surface shear. Collision nucleation is the dominant mechanism of secondary nucleation, whereby growing crys tals collide with the container walls, with a stirrer, or with other crystals. Homogeneous nucleation from clear solution is of special interest because it is an important pathway in which the crys tal polymorph (crystalline packing structure) is created-see the section below on Solution Mediated Polymorphism. The classical view of this process is that it occurs from the solute species clustering together in solution and then adopting the ordered arrangement of the crystalline state to minimize the free energy The Gibbs-Thomson theory for the critical clus ter size r e is also based on free energy minimization. Clus ters larger than r e must grow in order to reduce the free en118 ) ergy of the total system (solute cluster+ solution) while clus ters smaller than the critical size dissolve in order to reduce the free energy of the system In the Gibbs-Thomson theory, it is assumed that only sol ute transfers to the nucleus from a supersaturated solution (the composition of which is located in the metastable region of the phase diagram). It is also supposed that the mass of the nucleus phase is so small that the composition of the solution phase is constant during the nucleation event. The total free energy change, 6G consists of three terms: a change in bulk free energy of the solution, a change of bulk free energy of the nucleus, and a change of surface free energy of the nucleus. The resulting expression for a spherical nucleus is 4 3 6 I 6G=--m s out e + 4 m2y 3 V so lut e (1) where s olut e is the difference in chemical potential of the solute in the supersaturated solution and in the nucleus (this term is always positive); v s olut e is the molar volume of pure solute in the nucleus phase. The chemical potential differ ence can be written s olut e = RT Ln( I +a) ( 2) where a represents the relative supersaturation (C "'"'a' -C 'a ')/C 'a ,_ The major assumption in Eq. (2) is that the activity coeffi cient of the supersaturated solution is equal to that in the satu rated solution-a reasonable approximation in most cases. The leading term in Eq. (1) is always negative and represents the decrease in bulk free energy due to phase change. The second term in this equation contains the quantity y which is the surface free energy per unit area of nucleus (always a positive quantity) and represents the increase in free energy due to surface formation. The sum of these two terms pro duces a free energy plot with a single maximum that defines the size of a critical nucleus as shown in Figure 1 for the alpha polymorph of the simplest amino acid, glycine, nucle ated from aqueous solution at room temperature The critical nucleus size is given by r 2yv s olute c 6 s olute (3) This theory predicts that typical values for a characteristic length (diameter) of a critical nucleus are in the size range of hundreds of nanometers. For a glycine, the critical diam eter is approximately 600 nm. Recent computer simulations on small molecules predict critical nucleus sizes of 3-6 nm. The reason for the large discrepancy is currently unknown. Using atomic-force microscopy in situ during the crystalli zation of the protein apoferritin from its aqueous solution, Yau and Vekilov 111 1 2 1 have directly measured the crystalline Chemi c al Engin ee rin g Edu c ation

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C packin g s tructur e and critical nucl e u s s i ze of this m a t er i a l. They found critical nucl e u s s ize s in th e range of a few ten s of nanom e t e r s ( depending on the le ve l of s up e r sa turation ) A t y pical value i s 40 nm for th e c lu s t e r s ho w n in Fi g ur e 2two orders of m ag nitud e s maller th a n ex p ec t e d from tradi tional nucl ea tion theory for l a r ge mol ec ul es. The mol ec ul ar arrangement within the nucl e i were observed to be similar to that in the bulk crystal indicating that the crystal pol y morph is already established at the se s mall len g th sca le s. Mor eover, the authors s t a t e, Contrar y to the general belief the observed nuclei a r e not compact molecular clu s t e r s, but are planar ar rays of severa l rods of 47 mo l ecules set in one or two mono3D Nucleation of a g l ycine 11G (k J ) 4 1011 211 r(nm ) 100 200 300 400 500 Figure 1. Change in free e nergy as a function of nucl e us size for a-g l ycine grow n from aqueous so lu tion at room t e mp erature, w h e r e v g l ycine = 46.71 c m 3 / mol y = 148 1 erg/c m 2 a= 0 0 2, and RT= 2.5 kJ / mol. Figure 2. A flat n ear-cr iti ca l-siz e d cluster co nsistin g of approximately 20 apoferritin mol ec ules .1' 21 S prin g 2006 The Next Millennium in ChE) mol ec ul ar l ayers. Similarly une x pe c t e d nuclei structures might b e co mmon, es p ec i a ll y for a ni so tropic molecules Hence the nucl e u s s tructure s hould be considered as a variable by ad va nc e d th eo retic a l tr ea tm e nt s." Us in g s mall-an g l e neutron sca tterin g, Lefebvre et a / ., 1 13 1 d e t erm ined the critical length scales in phase separating pol m e r bl e nd s of pol y m e thylbut y lene-polyethylbutylene Th ey obtained r es ult s s imil ar to those reported for proteins namely critical diameters in th e range of 20-50 nm. Th e r efo r e, the current s tatu s of cla ss ical nucleation theory i s that it predict s critical nucleus sizes that are about two or der s of magnitude too high compared to the most recent mea s urem e nt s by Bal sara's g roup at UC Berkeley and Vekilov 's group a t the University of Hou s ton Moreover, classical theory doe s not pro v id e the molecular arrangement within the nucl e u sthi s i s an input to rather than an "output from the th eory. There are opportunities here for major improve m e nt s in nucl ea tion th eo r y that could h ave significant impact on c r ysta l e n g in eeri n g Nucleation i s an exce llent topic to include in the under grad uat e Solution Th e m10dynamic s course. I like to teach th e two-dimen s ional theory in which th e s olid nucleu s is taken to b e a rectangular lo ze n ge of fixed thickness with variable l e n g th a nd width (t h e number of dim e n s ions in the theor y i s eq u a l t o th e number of independent l e n g ths that are need e d to c h arac t er ize the s hap e and size of the nucleus ) Thi s model is mu c h ri c her than th e traditional one-dimensional s pherical nucleus d esc ribed above, which i s characterized by on l y one s patial variable: diam e t e r In the two-dimensional nucleation theor y, the critical nucleu s corresponds to a saddl e -p oint in the Gibb s free energy s urface which i s easy to calculate and visualize for und ergraduates Therefore, the expected nucle ation path corresponds to a trajectory through the free energy land sca p e over a sa ddle-point barrier. This provide s a nice analogy to tran s ition s tate theor y and the reaction coordinate over a sa ddle-point barrier in chemical reaction rate theory. Moreo ve r it i s easy to s how that the s hape of the critical two-dimen s ional nucleu s s atisfies the Wulff construction for a two-dim e nsion a l equilibrium shape That is the two-dimen s ional c ritic a l nucleu s a ttain s a shape that minimize s its total s ur face e nergy for the g iven ( faceted) volume Teaching this material to undergraduates also provides a good vehicle for explaining the difference between surface energy' and s ur face s tre ss. In the case of liquids all processes of interest The reversible work per unir area n eeded ro crea te a swfa c e-ifthe variarion in s 111fa ce area does nor c han ge rh e s 111fa ce de n s ir y of mo l ec ul es, rhen rh e spe c ifi c s w face work is s u,fa ce e n e r gy. 11 The re ve rsibl e work p e r 1111 ir area n eeded ro e lasri ca ll y s rr e t c h a preexis tin g stllface-if rhe va ri at i o n in S lll jace area c hanges the s 111 face density of mole c ul es, then rhe specific s wfa ce wo r k is s 11r face s tr ess. 119

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( The Next Millennium in ChE involve variations in area without varying the surface den sity, and the surface work represents a surface-free energy. The traditional processes involving surface energy are creat ing a soap bubble and cleaving a solid into two parts, while the traditional example of a process involving surface stress is blowing up a rubber balloon. Both types of energy are ex pected to play a part in creating a solid nucleus, yet there is no theory that accounts for this. Finally a good reason for teaching this material to undergraduates is to show them that not all is known, even in traditional areas of science that have been studied for a long time. Gr owt h Models Evidence suggests that crystal faces grow by one of three mechanisms: a screw dislocation mechanism, a two-dimen sional nucleation mechanism, or by rough growth. It is also known that different faces of a crystal may grow by different mechanisms, according to the solute-solvent interactions at the interface (surface-free energy) and the level of supersatu ration. At low supersaturation levels, or large surface-free en ergies, the screw dislocation mechanism is normally opera tive. The original theory, developed by Burton, Cabrera, and Frank, 1141 proposed that screw dislocations, which exist on real crystal faces at all supersaturation levels, provide an in finite source of steps onto which oncoming particles can be incorporated. According to this theory, growth occurs by the flow of steps across the surface, which forms a spiral. Spirals have been observed on many faces of many crystals 11 5 1 7 i (see Figure 3). At moderate levels of supersaturation, the two dimensional nucleation mechanism may apply. Above a criti cal level of supersaturation, the face is roughened and growth proceeds at a high rate. The BCF expression for the rate of growth normal to a sur face is: R Vhklhhkl hkl (4) Yhkl where v h k l is the lateral step velocity, hhkl is the step height, which can be approximated by dhkl (the interplanar spacing) for monolayer height, and yhkl is the distance between steps. Since growth occurs at kink sites (vacancies in steps where solute growth units can incorporate-see Figure 1 in Chen and Vekilov 11 8 1 for a beautiful image of kink sites on a step of crystallized ferritin), the lateral step velocity depends mainly on the density of kink sites. In the simplest case, molecules along the edges of a spiral are found in one of three microstates: a positive kink site, a negative kink site and no kink site. The energy for each of these microstates can be calculated, and if we assume that they occur in their most probable configuration, then the probability of finding a kink site along an edge is given by the Boltzman distribution. This 120 Figure 3. Four consecutive images of a spiral growing from a screw dislocation on a calcite crystal face .1' 71 (a} (b ) Figure 4. Reported and predicted morphologies for a-glycine crystallized from aqueous solution. ) (a) Experimentally grown crystal from Baek, et alJ 211 (b) Predicted shape using the form of the BCF model in Eq. (4) with a dimer growth unit. (c) Shape predicted by Eq. (4) using a modified monomer growth unit J2 6 1 Chemical Engineering Education

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C result provides a ni ce link between elementary statistica l mechanics and the kinetics of crystal growt h. (In m y experi e nc e, if yo u want to teach und ergraduates the methods of sta tistical mechanics so that they under s tand use the textbook by Kittel and Kroemer. 1 1 9 1) Crystal Shape It is well known that crystals grow in a variety of shapes in response to both internal and external factors. Some of these factors can be manipulated (e.g., so l vent type solution tem perature and s up ersaturation) by crysta l engineers to steer crysta l s toward a target s h ape or away from undesired shapes Experiments performed on the growth of crys tal s from sp h erical seeds have shown that flat faces appear during growth. Some of the faces that appear eventually disappear while others grow in size, eventually leading to a fully facet ted stationary (steady state) shape. The shape of crystals at thermodynamic equilibrium can be determined using Gibbs approach of minimality of the total s urface -free energy per unit vo lum e. This thermodynamic equilibrium condition leads to the Wulff construction to determine crysta l shape Yi I N -=constant 1= ... hi (5) where y i is the specific surface-free energy of face i, h i is the perpendicular distance between the origin and face i and N is the number of faces. Only very s mall particles (nanoparticles) can undergo rapid shape change to reach equilibrium, during which the size change is not s ub s tantial. For larger particles ho wever, the number of e l ementary transport processes that have to occur to ach i eve significant changes in shape is so l arge compared wi th the lowering of the s urf ace-free energy that the rate of eq uilibration becomes negligible. 1 201 For crys tals grown from seeds, steady state shapes (t hat have se l similar growth) are therefore observed more often than the equilibrium shapes Wulff 's condition was modified by Chernov 1211 (also see Cahn et af.,1 22 1 ) to determine the crysta l shape at steady state, given as: R 1 =constant, i= l ... ,N hi (6) where R i is the perpendicular growth velocity of face i. As noted in the previous s ub section, many mechanisms and mod e l s are avai l able to estimate the perpendicular growth veloci ties of facets, but in most so lu tion crystallizations only one model-the screw dislocation model [BCF model Eq. (4)] has the proven capabi lit y to correctly estimate the relative growth rates of crystals grown from so luti on. A comprehen sive va lid ation of this modeling approach i s given by Liu e t Spring 2006 The Next Millennium in ChE ) a/., 1 23 1 Winn and Doherty, 1 24 25 1 and Bisker-Leib and Doh erty. 1 2 6 1 The shapes of many organic crysta l s have been s u ccessfu lly predicted with this approach, e.g., urea grown from aqueous so lution ibuprofen grown from methanol and from hexane, adipic acid grown from water. Figure 4 compares the experi mental and predicted steady s tate growth s hapes of a. -glycine crystallized from aqueous so lution. Thi s i s a particularly sen si tive te s t of the approach due to the comp l ex network of hydrogen bonds that are formed in the solid state. Although there are many aspects of thi s modeling approach that need improvement, such as a priori identification of the nature of the growth units that incorporate into the growing crystal faces, the approach is already s ufficiently well developed for immediate application to engineering design. Although significant progre ss ha s been made recently on predicting the steady state shapes of organic materials crys tallized from so lution there i s le ss to report on the important related matter of predicting shape evo luti on from an initi a l seed or nucleus shape through to the final steady state s h ape. The only evolution models reported in the literature are for two-dimensional crystals, which apply to materials that crys tallize in flat plate-like shapes, s uch as succi ni c acid grown from water ( flat hexagonal crystals), and L-ascorbic acid (vi tamin C) grown from water (flat rectangular crystals). The dynamic s of shape evolution for three-dimensional crys tal s are quite complicated as faces, edges, a nd vertices appear or disappear during growth. The definitive study i s ye t to be done. Although some may di sag ree with me I think the topic of crystal growth and crystal s hape as outlined above is good material for inclusion in an undergraduate transport co ur se. Solution Mediated Polymorphism The phenomenon of polymorphism-a so lid crysta llin e phase of a given compo und resulting from the possibility of at least two crystalline arrangements a nd/or conformations of the molecules of that compound in the solid state -h as been known to exist for over two centuriesY 8 1 Despite this it s prevalence present s one of the greatest obstacles to the so lid sprocessing industry today To obtain the desired prop erties of the product the correct polymorph must be obtained s ince they have different physical properties: melting points solubilities, bioavailabilities enthalp i es, color, and many more. Differences between polymorphs are crucial for indus trie s such as the pharmaceutical industry, where differences in di sso lution rates between two polymorphs may mean that one polymorph is a potential product because of its high dis solution rate (high efficacy) while another is not due to its ne g ligible dissolution A dramatic example of thi s phenom enon is provided by the Ritonavir polymorphs .15 1 121

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( The Next Millennium in ChE Paracetamol (aceta minoph en) is an analgesic drug that i s u se d worldwide as a pain reliever Due to its commercial importance acetaminophen has been subject to many crys tallization experiments and, in particular polymorph studies. Paracetamol has three known polymorphs. Monoclinic paracetamol i s the thermodynamically s table form at room temperature and, therefore, it i s the commercially used form. Unfortunately, it is not suitable for direct compression into tablets, since it lacks slip plane s in its s tructure which are necessary for the plastic deformation that occurs during com paction. Consequently, it has to be mixed with binding agents, which is costly in both time and material. Crysta llization of the orthorhombic polymorph (form II) of paracetamol from solution is more desirable s in ce it undergoes plastic defor mation and is therefore suitable for direct compression. In addition, it is believed to be slightly more soluble than form I. Until 1998 there was no reproducible experimental proce dure available for the crystallization of form II from solu tion. The only method that had been reported for bulk preparation of form II was to grow it as polycrystalline material from fused form I. ) free energy, to the current state 1 3 0 3 1 In accordance with thi s rule, crystallization of a compound having two polymorph s will often proceed first with the growth of the metastable fo1m until the solution composition achieves the equilibrium solu bility of this form. When the sat uration concentration of the meta s table form is reached it will stop growing. The stable fom1 may have nucleated at any point, determined by rela tive kinetics, up to and includin g when the sa turation of the meta s table form is reached. The stab le form will then grow, thu s causing the solution to be under sa turated with respect to the metastable form, causing it to begin to di sso lve. Once the metastable form has completely disso l ved at the expense of the grow in g stable form, the stable form will grow until the so luti on reaches its equilibrium solub ilit y with respect to the stable formP 2 l For examp l e, a s napshot of the polymorphic transformation of glycine crystallized from a water/ethanol mixture i s s hown in Figure 5. At the beginning of the crystal li za tion beta-glycine ( needle ) crystals form first. This is the le ss stab le polymorph. After 10 minute s, the more stable poly morph alpha-glycine (shaped as a coffin), grows at the expense of the beta-glycine, which di solves. A more complete understanding of so lution-mediated polymor phism will involve appropriate integration of nucleation growth, and dissolution, with the thermo dynamic equilibrium phase dia gram for the polymorphs P 41 Crystallizer Design In 1998 Gary Nichols from Pfizer and Christopher Frampton from Roche [ 29 i de scr ibed a laboratory-scale process to crystallize form II from so lution. They found that the orthorhombic poly morph of paracetamol co uld be crystallized from s uper sa turated solution of indus tria l methylated spirits (etha nol with approximately 4 % methanol ) by nucleation with see d s of form II, main taining crystallization at a low temperature of O C and collecting the crystals within one hour after nucleation began. The typical yie ld achieved was l ess than 30 %, Figure 5. Two polymorphs of glycine in water-ethanol solution: alpha-glycine (shaped as a coffin) and beta glycine (needles} J3 3 1 Crystallization processe s are designed to achieve specific ma terial properties in the final so lid product which are normally de termined by the crystal purity polymorph, mean particle size, size distribution and crystal habit. The design decisions that but they proposed that when the process was optimized, a commercia l application was possibl e By having better con trol over the crystallization proces s, they managed to crystal lize only the orthorhombic polymorph and to have the de s ired crystal s hape. Ostwald noted in his Rule of Stage s describing phase tran s itions that it is not the most thermodynamically stable state that will normally appear first but that which is the closest in 122 influence these material charac teri s tic s include: choice of sol vent, tailor-made surface-active modifier s ,l3 5 37 l fines removal sys tem and the temperature and s uper sa turation fie ld s in s ide the crystallizer (w hich are detennined by the so lute feed concentration and temperature crystallizer temperature, ves se l volume and geometry, agitation rate, and/or antisolvent feed rate or evaporation rate, as appropriate). Buildup of im purities in the recycle streams also ha s the potential to sig nificantl y influence crystalline material properties. Chemical Engineering Education

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C Considering the fundamentals of crystallization it is tempt ing to envision crystals growing quietly in a uniform me dium. This is an ideal seldom if ever realized in indu s trial crystallization. In most industrial crystallization proce sses, crystals grow suspended with myriad similar crystals in large vigorously agitated vessels. Frequently the solution compo sition in the vessel is nonuniform both temporally and spa tially. Growing crystals are subject to collisions with other crystals, the vessel agitator, wall, and internals. These phe nomena have a significant sometimes profound effect on the properties of the resulting crystals. Crystallizer and crys ta lli zation proces s design attempt to reconcile and man age these competing effects to produce adequate, even superior crystals. Modeling crystallizer flows is critically important and pre sents many difficulties, s u ch as concentrated two-pha se flows turbulent flow, complicated geometries, and a particle phase that is changing in concentration and properties over time Despite these challenges advances in closure modeling nu merical so lution techniques, and computational power are beginning to make computational fluid dynamics (CFD) a useful tool for characteriz in g crystallizer flows. Advances have a l so been made incorporating the effect of the suspended particles on the flow field. Currently there i s great hope for Lattice Boltzmann tech niques to simplify the computational treatment of the eq u tions of motion making numerical solution much more effi cient. The techniques are also amenable to including the ef fect of so lid s [ 38 l and are becoming common l y u se d. Because they are so much more efficient than traditional solution tech niques, significantly more complicated and consequently more realistic problems can now be so lv ed. It remains a c hal lenge to incorporate changing particle size distribution (PSD) into these models but this is an area of current research and progress is being made.f 39 1 The ultimate goa l is to combine transport and population balance modeling. Only then will realistic PSD predictions be possible for a wide variety of non ideal systems. Progress has been made, but a model applicable to a wide variety of cond ition s remains el u sive SYSTEMS DESIGN / PROCESS SYNTHESIS Normally, lar ge amo unt s of dissolved so lut e r emain in so lution in the effl u ent stream of a continuous crystallizer, or at the end of a batch crystallization. In either case the crystals are separated from the so luti on and the liquor is recycled The crystallizer, therefore is part of a larger flowsheet which may involve reactors, di sso l vers, additional crystallizations, va riou s kinds of separators, heaters and coo l ers, etc. Both the structure of the flowsheet and the devices and their operating Spring 2006 The Next Millennium in ChE) Considering the fundamentals of crystallization, it is tempting to envision crystals growing quietly in a uniform medium. This is an ideal seldom if ever realized in industrial crystallization. policies influence the recycle flow rate and composition, which in tum influence the performance of the crystallizer. Surface active impuritie s and their buildup in recycle loop s can have a major impact (often adverse) on crystallizer performance In recent years geometric methods h ave proven to be use ful fo r the systematic generation of process flowsheets. One such tool the crystallization path map i s useful for finding feasible flowsheets in which crystallization steps occur. These maps are closely related to residue curve maps for the syn thesis of azeotropic distillation systems. 1401 The crystalliza tion paths are trajectories of the liquid composition in a crystal lizer as the solid is formed and removed from solution. 1 4 1. 42 1 The presence of eutectics and compounds causes the pre ence of crystallization boundaries which divide the map into distinct crystallization regions These regions are nonoverlapping and mutually exclusive; that is a liquid tra jectory that starts in one region cannot cross a boundary (ex cept by noncry s tallization means ) into an adjacent region. Within each region there i s one and only one crystal product, which may be a pure component, a eutectic, or a compound. Crystallization map s are useful for synthesizing flowsheets for adductive crystallization (w here a compound i s the de sired crystal product ), extractive crystallization, and many other embodiments. 143 451 Although the se maps are valuable for laying out process flowsheets, the accumulation of impu ritie s associated with process recycle and the effect on crys tal properties both remain difficult to predict. Therefore in tegrated pilot-scale testing including all recycle streams is still required for confident system design, but there are sig nificant modeling opportunities here that will enable more reliable and rapid development of proces s flowsheets. SUMMARY AND CONCLUSIONS During the last decade there have been significant advances made in every aspect of crystal engineering. New experimen tal techniques s uch as atomic force microscopy allow u s to 1 23

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( The Next Millennium in ChE explore crystal surfaces and embryonic nuclei to learn about their formation and growth, infrared and Raman spectros copy a llo w us to follow s up ersaturation c h anges and poly morphic transformations in situ while crystallization i s tak ing place. New models have been developed to predict the influence of both internal and external factors on crystal poly morph and shape. Molecular templates are being developed to control crysta l form and structure. Adva n ces in fluid me chanics and transport phenomena have added greatly to our understanding of mixing patterns and particle trajectorie s in side crystallizer vessels of rea l istic geometry. These a nd other advances not mentioned or not yet even anticipated, are ex pected to continue. Most of these advances are not being made by chemical engineers, however. And moreover they are taking plac e in isolation. There is a large disconnect for example, between the microscopic models for growth of individual crystal faces and the macroscopic models for CFD and PSD prediction. Perhaps the larger question is "How do we incorporate our rapidly advancing knowledge and modeling capabi l ity to make better products? There are major opportunities here for chemical engineers who must be encouraged to take up the challenge. Specific recommendation s for incorporating crystal engineering into chemical engineering research and undergraduate education include: Education 124 (I) Crystalline solids should be one of the core themes throughout the chemical engineering curriculum. Topics include: Thermodynamics coursethermody namics of solidliquid pha se diagrams and so lubilit y curves, s pinodal curve and metastable zone curve, traditional nucleation theor y. Transporl cou rs diffusion of solute through a so lution to a growing crystal s urface estimates of characteristic time s for bulk diffusion, surface diffu s ion and integration of so lute at kink sites on a crystal s urface, models for flow of steps across crystal s urfaces. R eaction Engineering co urs esimultaneous reaction and crystallization (i e precipitation). Separation co urs de s ign of batch and continuous crystallizers. D es i g n coursesim ultaneou s produ ct and proce ss design for crystalline products (e.g. a dye, a pigment or a simple pharmaceutical such as paracetamol-trade name T y lenol ). (2) Solid s tate chemistry should be part of the under graduate chemistry sequence. Topics include: crystal s tructur e and crystallography, nucleation ( both traditional and s tati s tical mechanics model s), so lid s tate bonding and bond chains, and S UJface growth mod e l s-es pecially the spira l dislocation model. ) There are numerou s useful monograph s and textbooks avail able on the s ubj ect of crystallization that may be used for teaching undergraduates. These include: Randolph and Larson ,l 46 1 Mullin, 147 1 and Davey and Garside. l 481 The last of these is short, inexpensive, and extremely well written. Un dergraduates should be happy to purcha se this book. Research Topics (3) New model s and experiments for understanding, directing, and controlling nucleation and polymorph se lection (4) Models for understanding and predicting polymorphic phase tran s itions-both so lution mediated and solid sta te tran sfo miation s (5) Models and experiments for predicting the effect of additives a nd impuriti es on crystal properties (e.g crystal s hap e, size polymorph) (6) Improved models for CFD of den se s usp e n s ion s of crystals that are growing inside a so lution crystallizer (7) Improved procedures for s imultaneous product and process design for c r ys talline particulate products; application and testin g of the proc ed ure s in s uch product sectors as: c hiral and pharmaceutical products home and personal care (e g., skin creams, s untan lotions) food (e .g ., margarine, chocolate, ic e cream), dyes and pigment s, bulk chemicals (e.g., adipic acid), and specialty chemicals ACKNOWLEDGMENT I would like to acknowledge helpful discussion s with Dr Daniel Green of the DuPont Company who influenced my thinking about this s ubject particularly in the area of CFD modeling REFERENCES I. Gardener C. R et al., "A pplication of Hi g h Throughput Techno l ogies to Dru g Substance and Dru g Product D eve l opme nt ," Fo1111datio11s of Computer-Aided Process Operations Coral Springs FL (2003) 2. Yalder, C., and D Merrifield Pharma ce uti ca l Technology," SmithK/in e Be ec ham R&D News 32(1 ) (1996) 3. Yilladsen, J. "Putting Structure into Chemical Engineering, Chem. En g Sci .. 52 2857 ( I 997) 4. Aguir, A.J., J Kr c Jr. A W Kinkel, and J.C Samyn "Effect of Polymorphis on the Absorption of Chloramphenicol from Chloram ph e ni co l Palmitate, J. Phann Sci., 56 7, July, 847-853 (1967) 5. Chemburkar S R. J. Bauer, K. Deming, H. Spiwek K. Patel, J Mor ris R H enry S. Spanton, W. Dziki, W. Porter, J. Quick, P. Bauer J. Donaubauer, B.A. Narayanan, M. Soldani, D. Riley and K. McFarland, Dealin g with the Imp ac t of Ritonavir Polymorph s on the Late Stages of Bulk Drug Proce ss Development," Or g. Pr ocess Res D ev 4 413417 (2000) 6. Desikan, S., S.R. Anderson, P.A. Meenan a nd P.H. Toma, Crystalli za tion Cha llen ges in Drug Development: Scale-up for Laboratory to Chemi c al Engineerin g Education

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C Pilot Plant and Beyond," C11rre111 Opini on in Drug Disc. & Develop ment, 3 6 723 (2 000 ) 7. Gordon, R.E and S.I. Amin "Crys talli za tion of Ibuprofen U.S. Patent Number 4 4 76, 248 ( 1 984) 8. Cu llit y, B.D., Elements ofX-Ra y Diffra c ti o n 2nd Ed., Addison-Wesley, Reading, MA (I 978) 9. Stout G.H. and L.H. J ensen X Ra y Stru c ture D etermination, John Wiley New York (1989) I 0. Gavezzotti, A. Crystal Symmetry and Molecular Recognition Chap t er I in Theoreti c al Aspects and Computer M ode lin g of the Mol ecu lar So lid State, A. Gavezzotti, ed., John Wiley, ew York (1997 ) 11. Yau S.-T. a nd P.G. Vek.ilov, Qua s i-Planar Nucleus Structure in Apo ferritin Crystallization," Nature 406 494 (2000) 12. Yau S.-T., and P.G. Vek.ilov Direct Observation of Nucleus Struc ture and Nucleation Pathw ays in Apoferritin C r ys talli za tion ," J. Am. Chem. Soc., 123 1080 (2001) 13. Lefebvre. A.A. J.H. Lee N.P. Bal s ara, and C. Vaidyanathan,J. Chem. Ph ys 117 9063 ( 2002 ) 14. Burton W.K. Cabrera, and F.C Frank "The Growth of Crystals and the Equilibrium Structure of Their Surfaces ," Phil. Trans R oy. Soc., A243 299 ( 1951) 15 Geil, P. Pol y mer Single Cr y stals, lnterscience ( 1 963) 16. Land T.A., A.J. Malkin, Y.G. Kutznesov, A McPherson, and J.J. D e Yoreo J. Crys tal Growth, 166 893 ( 1 996) 1 7. Paloczi G.T., B.L. Smith P.K. H a n sma D.A. Walters, and M .A.We ndman "Rapid Im ag in g of Calci t e Crystal Growth Using Atomic Force Microscop y with Small Canti l eve r s," Applied Ph ys i c s Le11er s, 73 1658 (1998) 1 8. Che n K., and P.G. Vekilov Evidence for the Surface-Diffusion Mechanism of Solution Cry s tallization from Molecular-Level Ob se va ti ons with Ferritin ," Ph ys. Re v. E 66 021606 ( 2002 ) 19. Kittel, C., and H Kroemer, Th er mal Ph ys i c s, W.H Freeman, ew York (1980) 20. H erring, C. "The Use of Classical Macro sco pic Concepts in Surface Energy Problems, in Stru c tur e and Pr o p er tie s of Solid Swfa ces, R Gomer and C.S. Smith eds., Unive r s it y of Chicago Press, Chicago ( 195 3) 2 1. Chernov, A.A., The Kin e ti cs of th e Growth Forms of Crystals, Sov. Ph ys. Cryst., 7 728 (1963) 22 Calm J .W., J .E. Taylor, and C.A H a ndw erke r "Evolving Crystal Forms: Frank s Characteristics R evisi t ed," Sir Charles Frank, OBE FRS,An Eightieth Birthday Tribut e, R .G Chambers, J .E Enderby and A. K e ll e r eds. Hilger New York ( 1 991 ) 23. Liu X.Y. E.S. Boek W.J. Briels and P Bennema Pr ediction of Crys tal Growth Morphology Ba se d on Structural Analysis of the Solid Fluid Int erface, Nature, 374 342 ( I 995) 24. Winn, D., and M.F. Dohert y, A New Technique for Predicting th e Shape of Solution-Grown Organic Crys t als ," A I ChEJ 44 250 I ( 1998) 25. Winn D ., and M.F. Doh er t y, "Mode lin g Crysta l Shapes of Organic Materials Grown from Solution A J ChEJ, 46 1348 (2000) 26. Bi ske r-L e ib V. and M.F. Doh e rt y, "Mode lin g Crystal Shape of Polar Organic Materials: Applications t o Amino Acids ," Cr ys tal Growth & D es ign, 3 221 (2003) 27. Bo ek, E S., D. Feil, W.L. Bri e l s, a nd P.J. Bennema, Cr ys t. Growth 114 389-410 (1991) SprinR 2006 The Next Millennium in ChE ) 28 Bern s tein J. P olymo ,phi sm in Molecular C r ysta ls Oxford Univer s it y Press Oxford UK (2002) 29. Nichols, G. and C.S. Frampton, "P h ys i coc hemical Characterization of th e Orthorhombic Polymorph of Paracetamol Crystallized from So lution J. Pharma ce uti c al S c ien c es, 87 684 (1998) 30. O s twald W.F.. Studien uber Die Hilding und Umwa ndlun g fester Korper ( Studies on the Formation and Transformation of Solid m a t rials )," Z. Ph y s. Chem., 22 289 (I 897) 31. Grant D.J.W., Theory and Origin of Polymorphism, in P o l y mor phism in Pharma ce uri c al Solids H .G. Brittain ed Vol. 95 of Dru gs and the Pharmaceutical Sciences, Marcel D ekker, New York ( 199 7) 32 Cardew, P.T. and R.J. Davey, The Kin e tic s of Solvent-Mediated Pha se Transformations ," P roc. R Soc. A398 4 I 5 (I 985) 33. Ferrari E.S., R.J Dav ey W.l. Cross A.L. Gillon and C.S. Towler Crystallization in Pol y m o rphi c Systems. The Solution-Mediated Transformation of B e t a t o Alpha Glycine, C1ystal Growrh and De s i g n ( 3 ) 53 (2 003) 34. Garcia E., C. Hoff and S. Veesler Dissolution and Pha se Transition of Pharmaceutical Compounds, J Cr y stal Growth 237-239 2233 ( 2002 ) 35. Michaels ,A .S. andA.R. Colv ill e, The Effect of Surface Active Agents on Crysta l Growth R ate and Crys t a l H ab it ," J. Ph ys. Chem., 64 13 ( 1960) 36. Klu g, D., and J.H. Van Mil, Adipic Acid Purification ," U.S. Pat ent Number 5 296,639 (1994) 37 Weissbuch, I. L. Addadi L. L a hav, and L. L e i serow it z, Molecular R ecogni tion at Crystal Int erfaces, Science 253 637 ( 1991) 38. Seta T. K Kono, and S. C h en, Lattice B o lt z mann Method for Two Phase Flow ," Im J. Modem Ph ys. B 17 169 (2003) 39. Brown D.B. S.G. Rubin and P Biswas, De ve lopment and Demon s tration of a Two{fhree Dimensional Coup led Flow and Aerosol Model Proceedings of rhe I 3rh A J AA Applied Aerodynamics Confer e n ce, American In s titut e of Aeronautics and Astronautics ( 1995 ) 40. Doherty M F., and M.F. Malone Concepllla l Design of Di sti l/ori on S ys r e ms McGraw-Hill, New York (2001) 41. Ricci J.E The Ph ase Rule and H eterogeneous Equilibrium D. Van Nostrand Co. New York ( I 95 I ) 42. Slaughter, D.W. and M.F. Doherty, Calcu l a tion of Solid-Liquid Equi librium and Crystallization Path s for Melt Crystallization Processes Chem. Engng Sci. SO 1679 ( 19 95) 43. Raja go pal S., K M. Ng, and J.M Dou g la s, Design and Economic Trade-Offs of Extractive Crystallization Proce sses," A/Ch J o urnal 37 437 (1991 ) 44 Wibowo, C. L. O Young, and K.M Ng, Streamlining Crystalliza tion Process De sign," CEP. JOO, 1 30 (2004) 45 Lashanizadegan, A. D.T.M. Newsham, a nd N.S. Tavare Separation of Chlorobenzoic Acid s by Dissociation Extractive Crystallization ," Chem. Engng S ci., 56 2335 (200 1 ) 46. Randolph A.O., and M.A. Larson Theory of Parti cu lat e Pr ocesses, Academic Press San Diego ( 19 88) 47. Mullin J .W., Crysrallizarion, Butterworth-Heinemann Oxford, UK (I 993) 48. Dav ey, R.J ., and J. Garside, From Molecules to C1J stallizers, Oxford Un i ve r sity Pr ess Oxford UK (2000) 0 125

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( The Next Millennium in ChE ) I NSIDE THE CELL A New Paradigm for Unit Operations and Unit Processes? JEROME 8. SCHULTZ University of California Riverside California T raditionally the chemical engineering paradigm for de signing industrial plants has been to separately con sider unit operations and unit processes. Although these terms are not prevalent in current curricula, courses in separations reaction engineering, polymer engineering etc. reflect this traditional view. The usual scheme of process development starts at the labo ratory bench. And with experimentation and exploration, con ditions are optimized and then the process goes through a scale-up procedure to reach commercial production needs. Recent advances in MEMS technologies however have led to the implementation of Lab-On-a-Chip devices such as the integrated DNA analysis chip developed by Bums, et a/. 111 ( s ee Figure 1). These analytical devices bring together vari ous elements of unit processes such as separation steps reac tion steps and process control (detection and sensing proce dures). The capability for miniaturization and integration has led some chemical engineers ( e g. Klavs Jensen) to envision an entirely new paradigm for production methods i. e., scaling down instead of scaling up Figure 2 from Professor Jensen s Web site succinctly illustrates thi s contrast in paradigms. Given the immense efforts in MEMS and nanotechnology toward miniaturization and integration, one can readily specu late about potential future methods for carrying out chemical processes through the application of these technologies. The 126 organizational structure of biological cells could have im portant lessons and impact in this regard As the extensive structural and operational characteristics of the biological cell are being revealed it is becoming clear that biological sys tems have evolved with a much more integrated design para digm of processes and operations than the traditional chemi cal engineering approach. J e r o me Schult z received his B S and M.S in chemical engineer ing from Columbia University, and his Ph.D. in biochemistry from the University of Wisconsin in 1958 He started his career in the pharmaceutical industry ( Lederle Laboratories) then joined the University of Michigan where he was chairman of the Department of Chemical Engineering He spent two years at the National Sci ence Foundation as deputy director of the Engineering Centers Program. In 1987 he joined the University of Pittsburgh as director of the Center for Biotechnology and Bioengineering, and was the founding chairman of the Department of Bioengineering-a nation ally ranked degree program in bioengineering. He recently spent a year at NASA s Ames Research Center as a senior scientist in their Fundamental Biology Program In 2004 Dr. Schultz joined the fac ulty at the UC Riverside as the director of the newly formed Bioengi neering Program and the Center for Bioengineering. He is a member of the National Academy of Engineering a Fel low of the American Association for the Advancement of Sci ences Editor of Biotechnology Progress and was a founding Fellow and President of the American Institute for Medical and Biological Engineering Copyrig ht C h E Di v i sio n of A SEE 2 00 6 C hemical En g ineerin g Edu c ati o n

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C New a dvanc es in ge nomic s, proteomics, metabolomics, ce ll s i g n a lin g, and control hav e a llo we d th e documentation of th e thou sa nd s of species and int erac tion s th a t co mpri se th e int e n a l milieu of cells Thi s vast amount of information h as a low e d th e harn essi n g of biolo gica l ce ll s for man y purpo ses s uch as preparation of man y biolo gics (e.g., insulin and EPO [erythropoietin, monoclon a l a ntibodi es]), as well as th e u se SAMPLE L OAD ING M~~rNG MIXING LO~~NG ELE~ES IS r7 .-------,.-----, 1 > :~:;;ii 11 i ~f1li :1illilllilllll1:i .'_: i!~il Iii: r : ; ; ~,;, : ~,: ii, 1 1 1! M _11111 1 1 1 11 1 111111 1 11m 1 ,i i ,i ,i ,: i,,,1 I: Figure 1. An examp l e of a Lab-On-a-Chip device. This is a D NA analysis sys t em devised by Mark Burns and associa t es .11 1 Various unit operations including m eter ing mixing reactions separations, and detection are co mbined in a si ngle device. I f 50 ml < 0 C MIT 5 li ter no w? temperature ? Not ro scale Figure 2. Klavs J e n sen's co n ce pt for a new paradi g m in c hemical process developm e nt that utilizes the multiplexing capabi liti es of MEMS technology to ca rry ou t integrated synt h esis and separation operations in th e same unit Spring 2006 The Next Millennium in ChE ) of ce ll s for detoxification of h erbic id es. Much of our thinkin g related t o th e future of biot ec hnol ogy i s b ased on our app r ec iation of biolo gica l sys t e m s d duc ed from th e dissection a nd se p ara tion of th e co mpon e nt s of ce ll s s u c h as enzymes s i g nalin g proteins antibodies RNA a nd D NA. Much of th e ri c hn ess of biological sys tem s, how eve r r es ide s in the s tru c tural features of cells. To dat e, man y of th e st ru ct ural e l e m e nt s that h ave been deduced from elec tron micrographs are categor i zed as orga nell es. Some of th e classes of o r ga n e ll es that h ave been id e ntified include the nu c leu s, mito c hondri a, l ysoso m es, p eroxiso me s, vesicle s, c hloropla s t s, a nd golgi (F i g ure 3) It i s clear that cells are n o t a b ag of e n zy me s a nd s ub s trat es i .e., a CSTR. Although the morphol ogy of th ese s tru c tural e lement s i s fairly we ll characterized b y e l ec tron micro sco pic method s, the functional and d y nami c biolo g i ca l/ c h e mjc a l pro cesses th a t are taking place in th ese s tructures are not we ll und ers tood at all. Early hint s from the s tud y of so m e of these organelles h ave r evea l ed th a t biology does not se parat e unit processes from unit operations, but ra th er int egrates th e m. For exa mpl e, in c hloropla s t s the ca ptur e of photons a nd fixation of car b o n dioxid e into carbohydrates s imult a neou s l y results in photol y s i sthe se paration of proton s a nd oxygen evolution. Ribo so m es integrate th e ge n etic code a nd prot e in sy nth es i s Most organelles are known to be co mple x multi-membra nous s tru c tur es, but the compos iti on a nd d eta iled organiza tion of these unit s are not known One r easo n for the lack of detailed und e r s t a ndin g i s that the typical dimensions of th ese s tru c tur es i s on th e order of n a n ometers and thu s below the r eso lution of optical mi crosco p es. So th ey cannot be visual i ze d in d e tail while in a normal functional mode. This lack of Ce ntriole Lysosome Huclear en v elope l Hu c l eo lu s Hu c l e u s C hrom ati n Nu c l ea r pore Figure 3. Diagramati c illustration of the various s tru tures within a ce ll iJlustratin g the comp l ex structures inside of ce ll s that are responsible for much of th e biosynthetic activities of Ji vi ng systems 1 27

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( __ li_'h_e_N_e_x_t_M_,_,_e_n_n_iu_m __ in_C_h_E __________________ ) GJass fiber Li gh t wavelength ( A ) 500 nm Probe : Incident light /l.=500nm aperture size ( a) evanescent field tip-sample gap Sample: feature size :ikindepth Optics : 25-lOOnm a/n 5-50nm 0co Far field detector Interference effects 1 100 mm .:\/4 Fig u re 4. Operational characteristics of near field microscopy (left] Close-up of the optical scanning probe (right). This is one of the devices that will allow the visualization of structures within living cells and their behavior (a) Ex=395 nm Em=527 nm Ex=395 nm + Glucose YFP -Glucose GBP (b) ~Thr-Ser--~Gly-Thr~ Em=527 nm Reduced FRET ,---" GBP Fig u re 5. Glucose-responsive protein engineered from a glucose binding protein from E coli, and two different green fluorescent proteins. This type of structure can be introduced into a cell via a plasmid to result in the biosynthesis of the sensor protein within the cell (a) In the absence of glucos e the two fluorophores are in close proximity and exhibit fluorescent energy transfer (FRET) (left). In the presence of glucose the protein opens, and FRET is reduced. (b) Structure of the fusion protein J 101 Figure 6. Confocal image of a yeast cell containing a maltose responsive protein similar to that illustrated in Figure 5. The intensity of fluores cence is indicative of the concentration of maltose in various regions of the cell. By incorporating various indicator proteins of this type within cells one could monitor the dynamics of biosynthesis of specific biomolecules in space and time. Vis a vacule (Bar= 1 micron). 111 1 knowledge has hampered our ability to mimic these biologi cal systems for chemical processes. Hope is on the way, however. To deal with this issue, indi rect methods are under active development to elucidate mechanisms of the functioning of organelles. Many new instrumental techniques are being developed to provide some real-time measurements of the behavior of sub cellular structures These techniques include confocal rnicros copy, 1 21 two-photon microscopy ,13 1 and optical coherence to mography 1 4 1 Near field microscopy, 1 5 1 Figure 4 allows the 12 8 Ch e mi c al En g in ee rin g Edu c ati o n

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C a 600 b 0 22 0.20 0.18 0 16 0 0. 14 a, 0 12 0 10 0 08 0.06 0 04 0 02 0 00 4 5 5 0 5 5 Sprin g 2006 600 1000 1200 1' 00 Raman Sh i ft (cm 1 ) 6 0 6 5 7 0 pH Bulk Solution 1600 180< 7 5 8 0 8 5 The Next Millennium in ChE ) vis uali za tion of s tructural elements near the s urface of the cell. Ba s icall y an optical fib e r is drawn down to diameter s le ss than the wavelength of light and placed in contact with th e cell's outer membrane. The probe i s scanned across the cell membrane to pro v ide a map of s tructures just beneath the membrane surface. Several clever co nc epts ba se d on various reporter tech niqu es ha ve also been described recentl y that are beginning to g ive s pecific d y namic data on intracellular events. The rap idly expanding knowled ge ba se on the s tructure and proper tie s of g r ee n fluore sce nt proteins has opened up man y oppor tunitie s for the protein e n g ineering of intracellular probes A multitud e of technique s i s available for incorporating pla s mid s for th ese protein s into cells. The se reporter indicator s can be e ith e r freely mobile within the cell or loca l ized in spe c ific s tructure s. 16 7 1 Ro ger T sie n and hi s gro up 1 8 91 have pioneered the use of g r ee n fluorescent protein s as functional probes for biomol ec ul es within cells ba se d on the technique of fluore s ce nce energy tran sfe r ( FRET ) One rec e nt application of thi s approach ha s been to monitor s ugar concentrations within cells. We 1101 engineered a fu s ion protein consisting of a glu cose-binding protein and two different green fluorescent pro tein s as s hown in Fi g ure 5. The s ugar-binding moiet y under goes a co nformational c han ge w hen glucose bind s, s uch that it c h a n ges th e di s tanc e b etwee n th e GFP a nd YFP in a man ner that r es ult s in a change in FRET. Fehr et a / .,1 111 incorpo rated a s imilar malto sebinding protein into yeast cells. Us in g confocal microscopy they were able to monitor the dis tribution of maltose throu g hout the cell, Figure 6. Other technique s for monjtorin g the concentration of ma teri a l s w ithin ce ll s are ba se d on insertin g tiny "biosensor" p a rticl es within cells. R ao ul Kopelman and co lleague s 11 2 1 hav e d es i g ned va riou s mat eria l s called PEBBLES for measur ing oxygen s ugar s, and pH within cells by optica l techn i ques T a ll ey, et a l .,11 31 have extended thi s approach by inserting functionali ze d go ld particle s within cells that s howed changes in the Raman s pectrum with local pH changes. Again, these particl es co uld be placed within ce lls to mea s ure the distri bution in acidity within cells, Figure 7 In order to measure Figure 7. Use of particles placed w ithin ce ll s to monitor intrace llul ar analyte co n ce ntrations by s urfa ce e nhanced Ram an spectroscopy. In this examp l e of intracellular monitoring a compound that s h ows diff ere nt Raman spectra in its two ionic forms, is used to monitor th e pH distribution within ce ll s .1' 31 ( a ) Structure of th e probe particl e and Raman spectra at different pH's ( b ) The pH behavior of Raman spectra (c) Distribution of nanoparticles within ce lls 129

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( The Next Millennium in ChE local enzyme activity within cell s Weissleder, e t a/. I I 4I in corporated a probe polymer with an enzyme hydrolysable link between two fluorophore s (s ee Figure 8) With the increased amount of inform a tion afforded by these imaging techniques software to manag e and display this data in a meanin g ful fa s hion has b e come important. Several groups ar e developing appropriate s oftware for thi s purpose I I 5 I 8 1 Government agencie s are targeting technologies for im provement in intracellular imaging s en s itivity. For example the NIH recently funded nine center s to develop cellular im aging techniques. Description s of the s e research effort s as r e ported on the NIH Web s ite ( ) ar e quoted below. 1 30 OVERVIEW Th e E x pl o r a t o r y C e nt e rs f o r th e D e v e l o pm e nt o f Hi g h R eso luti o n Pr o b es f o r Ce llular Ima g in g s upp o rt multi in ves ti ga t o r t ea m s t o d eve l o p n ew t ec hn o l og i es that e nabl e hi g h e r -se n si ti v i ty bi o l og i c al ima g in g in li v in g ce ll s. Ea c h of th e nin e c e nt e r s w ill f oc u s o n d iffe r e nt s trat eg i es fo r p ro b e d eve l o pm e n t, ce llular d e li ve r y, pr o b e tar ge ti ng, and s i g nal d e t ec ti o n t o impr ove d e t ec ti o n sc h e m es b y a fa c tor o f JO t o JOO A maj o r e mpha s i s o f thi s initiati ve is t o appl y n o v e l, hi g h-ri s k appr oac h es t o c r e at e fundam e ntall y n e w pr o b e s w ith e nhan ce d s p ec tral c hara c t e ri s ri cs Th e ultimat e go al i s t o d eve l o p pr o b es and im ag in g sys t e m s that ca n b e u se d t o r o utin e l y ac hi eve s in g l e -m o l ec ul e se n s iti v i ty fo r ima g in g d y nami c pr ocesses in li v in g ce ll s. Th e ce nt e r s a r e fund e d in co njun c ti o n w ith th e N IH R o admap for M e di c al R ese ar c h as p a rt of th e "New Path w a ys t o Di scove r y," an effo rt t o a d v an ce o ur kn ow e d ge of bi o l og i ca l sys t e m s b y buildin g a b e tt e r t oo lb ox f o r m e di ca l r esea r c h This initiati ve o ri g inat e d in NIGMS and w as /a/ e r ad o pt e d b y th e R o admap NIGMS c ur re ntl y s upp o rt s seve n o f th e c ent e r s a s R o admap-affili a t e d g rant s. Fundin g fo r all nin e ce nter s i s ex p ec r e d t o t o tal appr ox imat e l y $ 25 milli o n ove r fo ur ye ar s ($6.8 milli on th e first ye ar ) 1. Fluorescent Probes for Multiplexed Intracellular Imaging. K ev in Bur gess, Ph.D Prin c ipal ln ves ti ga t o 1 ; T exas A& M U ni vers i ty R esea r c h e rs fr o m T exas A& M U ni ve r s i ty a nd th e U ni ve r s i ty o f P e nns y l v ania plan t o c reat e n ove l pr o b e se t s co mp ose d o f multipl exe d thr o u g h-b o nd e n e r gy tr a nsf e r cas s e tt es, u s in g multipl e link e d d o n o r a cce pt o r d ye pair s that a r e o ptimi ze d f o r ce llular ima g in g Th ese pr o b es, w hi c h eff i c i e ntl y a b so rb li g ht at o n e wave l e n g th e mit a mplifi e d f lu o r esce nt s i g n a l s a t diff e r e nt reso l v abl e w a ve l e n g th s close t o th e r e d-inji r e d r eg i o n.far r e m ove d fro m ce llular aut o flu o r esce n ce. Th e d ye casse // es w ill be s p ec ifi ca ll y adapt e d fo r /ra c kin g int e ra c ti o n s 2. A of prot e in s in ce ll s, ultimat e l y w ith s in g l e -m o l ec ul e d e t ec ti o n Sub-nm Dendrimer-Metal Nanoclusters as Ultrabright, Modular Targeted in vivo Single Molecule Raman and Fluorescence Labels R o b e rt M D ic k so n Ph.D. Prin c ipal ln ves ti g at o 1 ; G eo r g i a In s t i tut e of T ec hn o l ogy M e tal n a n ocl u s t e r s co mp ose d of s il ve r and go ld a t o ms s tabili z e d o n organ i c d e ndrim e r s, ex hibit s tr o n g si zed e p e nd e nt e mi ss i o n thr o u g h o ut th e v i s ible and n ea r-infrar e d s p ec trum Th e s p ect ral c hara c t e ri s ti cs of th ese clust e r s -th e ir s m a ll s i ze ( < 1 nm ) and s h o rr a nd hi g hl y radi a ti ve No sign.al Target in,teraction Signal n ) Figure 8. Exampl e o f a p o lym e r prob e to d e t e rmin e e n zy m e a c tivit y w ithin a ce ll In thi s c as e th e purpo se w as to monitor th e a c ti v it y of a proteol yt i c enz y m e within c ells. A sp e cial pol y m e r substrate was created that c ontain e d the p e ptid e bond that the e nzym e cl e av es and fluorophor e s (indi c at e d by the circl e s) that se lf-qu e n c h wh e n in close proximit y. When th e p e ptid e bond is cl e a ve d b y th e e nzym e of int e r e st th e f lu oro phor e s ar e se parat ed and qu e n c hin g is pr eve nt e d Thu s, monitorin g th e app ea ran ce o f fluor esce n ce g i ves a m e a s ur e of lo c al e nz y m e ac ti v it y. U pp e r pan e l : S c h e mati c of th e c on ce pt. L ower Pan e l: E x ampl e s tru c tur e of th e probe pol y m e r t o m eas ur e e n zyme a c ti v it yJ 1 4 l C h e mi ca l E n g in ee rin g Edu c ati o n

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C lifetimes -c r e at e si g nal s that ha ve th e pot e ntial t o b e sev eral o rd e rs of m a g nitud e hi g h e r th a n co nv e nti o nal lab e l s. G ra nt ees fro m th e G eo r g i a Institut e o f T ec hn o l ogy and Em o r y U ni ve r s it y plan to fun c ti o nali ze th e nan o c/u s t e rs f o r a/fa c hm e nt t o diff e r e nt bi o l og i ca l tar ge t s an d t o d eve l o p sin g l e m o l e cul e ima g in g m e th o d s t o facilitate d e t ec tion o f rh e si g nal in s id e ce ll s 3. Single-Molecule Fluorophoresfor Cellular Imaging William E. M oe rn e ; Ph.D ., Prin ci pal ln ve stigato, ; Stanford University A g r o up fr o m Stanford a nd K e nt Stat e U ni ve r s i ty plan s ro s y nth es i ze and c hara c t e ri ze a n ew cla ss of hi g hl y emi s siv e ( di cy an o dih y dr o furan ) flu o r o ph o r e s that e xhibit lar ge in c r e a ses in s i g nal w h e n b o und r o ri g id s wfa ce s The strat egy f o r in co ,p o ratin g rh e pr o be s int o ce lls w ill b e bas e d up o n rh e ge n e ti c all y e n co ded t e tra cy steine-biar s eni c al tar ge tin g sys tem and th e n t es t e d f o r s in g l e m o l ec ul e s p ec ifi city and d e t ec ti o n in ba c t e ria. 4. Bioaffinity Nanoparticle Probes for Molecular Cellular Imaging Shumin g N i e, Ph.D. Prin c ip a l ln ve sri g at01 ; Em o r y U ni ve r s i ty and G eo r g i a T ec h A co llab o rati v e g roup w ill d eve l o p a n ew cla ss o f p o l y m e re n c apsulat e d bi oco nju ga r e d lumin esce nt nan o particl e s with e nhan ce d o pti c al prop e rti es, ce llular d e liv e r y and tar ge tin g / bindin g fun c ti o n s fo r real-tim e and multi co l o r ima g in g in li v in g ce ll s. Th e f oc us will b e o n core -sh e ll se mi co ndu c t o r quantum d o t s be c au se o f th e ir impr ove d bri g htn ess, r es i s t a n ce a g ain s t ph o t o bl e a c hin g a nd s imultan eo us multi c olor exc it a tion Th e r e s e ar c h e rs w ill t es t rh e pr o b e s and th e ir abili1 y r o d e t ec t th e m in s tudi es aim e d ar findin g th e s ub ce llul a r l oc ati o n s of p5 3, nucl e ar fa c t o r B and andr og en r ece ptor in li v in g ce ll s 5 Probes for Quantitative Optical and Electron Microscopy David W. Pist o n Ph.D. Prin c ipal ln ves ri g ato1 ; Vand e rbilt U ni ve rsi ty M e di c al C e nt er A g r o up from Vand e rbilt w ill d eve l o p n ew flu o r es ce nt prob e s in rh e visibl e and infrar e d sp ec tral r eg i o ns ba se d o n thr ee appr o a c h es: ge n e ricall y e n co d e d pr o t e in s lanthanid e c h e l a t es and nan oc r y sral s ( quantum d o t s). Ea c h a ppr o a c h w ill b e t e st e dfor ima g in g of a pr o t e in in th e plasma m e mbrane as w e ll as an intra c ellular targ e t. Sub c el/ular r e soluti o n flu o r e s ce n ce ima g in g b y wid e field d eco nvoluti o n co nf oc al, and multi-ph o ton exc itati o n mi c r o s c op y w ill b e u se d t o impl e m e nt and r e st rh e n ew d e t ec ti o n sc h e m e s b ase d o n s p ec tr a l and rim e g at e d r eso luti o n T o r eac h th e hi g h es t r eso lution th e r e sear c h e r s w ill d e t e rmin e th e ut i li ty Sprin g 20 0 6 6. 7. 8. The Next Millennium in ChE ) a nd limitati o n s of u s in g rh e n e w pr o b es f o r dir ec t d e t ec ti o n b y e l ec tr o n mi c r osco p y f o r co rr e lati ve im ag i ng. Imaging Single Proteins in vivo with Quantum Dots S a nf o r d S im o n Ph.D ., Prin c ipal lnv e sti g t 01; R ockefe ll e r U ni ve r s i ty R e s e ar c h e r s f ro m th e R oc k e f e ll e r Univ e rsity plan t o e xt e nd and o ptimi ze an i n v i vo transs pli c in g and ex pr esse d-p ro t e in li g ati o n a ppr o a c h t o li g at e quantum d o t d e ri va ti v e s ro cy t oso li c o r int eg ral m e mbran e pr o t e in s. Th e ir s trat egy includes d eve l o pm e nt of a co nditi o nal pr o t e in tran s -spli ci n g appr oa c h th a t wi ll a ll ow pr o b es t o b e li g at e d t o th e tar ge t fo ll ow in g a d es i g nat e d fun c ti o nal int e ra c ti o n Th e ce llular f a t e o f "ac ti v at e d pr o t e in s w ill thus b e m o nit o r e d b y a c ha nge in th e s i g n a l e mitt e d b y th e p ro b e. Th e t ea m int e nd s t o u se th ese t oo l s t o s tud y e x ocy t os i s and t ran s p o rt thr o u g h nucl e ar pores Light-Activated Gene Expression in Single Cells R o b e rt H S in ge r Ph.D., Prin c ip a l In ves ti g at o r Alb e rt E in s t e in Co ll ege of M e di ci n e I nves ti ga t o r s from th e A lb e rt E in s t e in C o ll ege of M e d icine w ill deve l o p a ph o t oac ti v atabl e ge n e that up o n ex p os u re t o li g ht b eg in s trans cr ipti o n o f v i s ibl e na scen t c hain s o f R N A Th e ec d y s o ne r es p o n se e l e m e nt a nd a cage d ph o t o a c ti v atabl e ec d yso n e ge n e i nt o w hi c h an R N A r e p o rt e r has b ee n in s ert e d w ill b e us e d. G e n e ex pr e ssi o n will b e ini t i a t e d b y un cag in g th e ec d yso n e in v i vo b y co n ven ti o n a l a nd two -ph o t o n mi c r osco p y Th e sys t em w ill b e e n g in ee r e d int o ca n ce r ce ll s and th e n im age d i n tra v it a ll y in tum o r s. The d y nami c s of s in g l e R NA m olecu l e m ove m e nt s and di s tributi o n w ill b e m o nit o r ed. Library-Based Development of New Optical Imaging Probes Ali ce Tin g Ph.D ., Prin c ipal In ves ti g at o r M ass a c hus e tt s Institut e o f T ec hnol ogy Th e in ves ti g at o r s plan thr ee parallel approa c h e s to ge n e rat e s m a ll m o l ec ul e and ge neti c all y e n co d e d pr o b es th a t can b e t a r ge t e d t o s p ec ifi c R N A o r pr o t ein se qu e n ces in s id e li v in g c ells In th e fir s t librari es o f flu o r o ph o r e s w ill b y s y nth es i ze d in a co mbin a t o ri a l fas hi o n and th e n scree n e d f o r th e ir abili ty t o l a b e l s m a ll p e ptid e m o tif s o r R N A aptam e r s with hi g h sp ec ifi c it y In th e se c ond app roac h th e natural ba c t e rial e n zy m e biotin trans/ e ra se w ill b e r e e n g in ee r e d to catal yze cov al e nt lab e lin g o f fluor e s ce nt prob e s t o peptid e s in s id e c ell s Third a s y st e mati c approa c h usin g a S ee Inside the Cell ------------co ntinu e d o n pa ge J 3 9 / 3 1

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.tA ... 5 ... ._c u r r_ i c_u_l_u m ______ __ ) ENERGY CONSUMPTION VS. ENERGY REQUIREMENT L.T. FAN, TENGYAN ZHANG, AND JOHN R. SCHLUP Kansas State University Manhattan, KS 66506-5102 T oday the phrase "energy co n s umption is popularly spoken and written_[IJ Nevertheless, caution should be exercised for its contin u ed use especia lly in th e instruction of not only thermodynamic s but also various ot h er courses in engineering, including tho se in c hemi ca l e ngineerin g The first law of thermod y nami cs te ac he s that energy is al ways conserved in an i so lated ( or closed) sys tem ; it i s neither c r ea ted nor destroyed by any proc ess, sys tem or phenom e non .1 2 1 In contrast, the available e ner gy analysis, which i s the co mbination of the first a nd second law s of thermody n a mic s, indicates that in the real world the ava ilabl e energy i s never conserved, even in an i so lat ed (or closed) sys tem Eve n thou g h in ideal circumstances available energy is only theoreticall y conserved, th e reality is th at it is ince ssan tly con s umed or di ss ipat e d by any proc ess, sys tem or phenom e non_ l61 s 1 This co n s umption of available energy----or exergyi s ac co mpani e d by an increase in entropy, s i g nifying the dissipa tion of avai lable e nergy (or exergy) to th e s urroundin g e n v ronments. The di ss ip a tion of this available energy (exergy) reduces it s potential or availability t o perform u se ful work. Similar to enthalpy exe r gy is a s tat e property of any sys tem. The enthalpy as well as exe r gy contents of m a terial s are L. T. Fan i s University Distinguished Professor, holds the Mark H. and Margaret H Hulings Chair in engineering and is director of the Institute of Systems Design and O p timization at Kansas State University He served as department head of chemical engineering between 1968 and 1998 He received his B S from National Tai wan Uni versity, his M.S from Kansas State Uni versity, and his Ph D from West Virginia Uni ve rsit y, all in che mical engineering in a ddition to an M S in mathematics from West Virginia University T engyan Z han g is a research associate in the Department o f Chemical Engineering at Kansas State University She rece iv ed her B S a nd M.S from Tianjin Universit y, and her Ph.D. from Kansas State University all in chemical engineering in addition to a B S in system engineering from Tianjin University, and an M.S in computer science from Kan sas State University John R Schlup is presently a pro fessor in the Department of Chemical Engi neering at Kansas State University H e ob tained B S degrees in both chemistry and chemical engineering from Kansas State University and a Ph D degree in chemical en gineering from the California Institute of Tech nology Hi s c urrent research interests include the application of chemical engineering prin ciples in bioprocessing and the development of new materials from biomass Copyr i g ht C h E Division of ASEE 2006 / 32 C h e mi ca l E n g in ee rin g E du ca ti o n

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mea s ured relative to the dead s t a t e, i .e., the exte nded s tan dard s tat e It is defined by th e e n viro nm e ntal temperature the environmental pre ss ure and the d a tum-level s ubstance s Any element i s part of the corresponding datum-level substance which i s defined as being thermodynamically stab l e, existing in ab undan ce and containing no available energy. 1 8 11 16 19 1 The environmental temperature and pr ess ure whic h vary accord in g to time and place are u s u a lly adopted as the datum level temperature and pre ss ure ; de s pite thi s, the y are of ten s pecified as 298 Kand I atm respectively, for conve nience and a l so to be consistent wi th the conventionally d e fined s tandard state. MASS, ENERGY AND AVAILABLE ENERGY BALANCES A system in which a phenomenon or proce ss of interest occurs i s thermodynamicall y defined or s pecified by its ma ss, energy, and available energy balan ces. 8 ''1 3 1 9 21 1 The follow ing s ub sect ion s outline the se thr ee bal a n ces for sys tem A or s impl y th e sys tem ," ha v ing multiple input and output streams und e r the s teady-state, open-flo w co n ditions d e picted in Fig ur e l, on th e ba sis of a unit tim e, i .e., the rate. Fi g ure 1 exhib it s an i so l a ted overall sys tem ; b es id es sys tem A, it encompasses work and heat so ur ces and s ink s, and the entire sur rounding s, i.e environments. It is po st ulated that except en e r gy ( enthalpy) and a v ailable energy (exe rgy ) of ma ss flow ing through sys tem A, other forms of energy-such as poten tial energy and kinetic energy-are negligible. Thus the changes in the enthalpy and exergy are induced by the trans f e r of energy (between system A and it s s urroundings or other sys tem s) as heat or work. For s implicity the aforementioned three balance s will be written around system A by referring to Figur e 1 and with the notation s g iven in the section on nomenclature. Mass Balance B y takin g into account both convective and diffu s ional flow s, the mass balance around sys tem A yie ld s ( l ) e In term s of the molar flow rate the above expression can b e rewritten as s urroun mgs N I M l T m 1 I W 1I I Q 1 I I s ---+ A I 8 2 ---+ T I I W 2I I Q 2I ', N2 M2 T m2 Spr i ng 2006 (T o, P o) l ( W x)ol I Q o l ---+ c 1 I ---+ c 2 I I 1 L -----Figure 1. S c hematic diagram of an isolated overall system encompass in g a steady-state, open-flow system (sys t em A} a h ea t sou r ce at t e perature T m, (system Ml} a heat sink at temperature T m, (system M2} a work source (s y stem NJ) a work sink (system N2} and th e e ntir e surroundings at the environ mental temperature of T 0 and the environmenta l pressure of P 0 In the t ext, e nt eri n g stre ams B 1 B 2 are d esig nat e d by s ubs cr ipt i ; and ex itin g streams C 1 C 2 L--the last being the leaking stream (leakage)-are designated by subscript e ; the useful and leaking streams among the ex iting str ea ms are differentiated by additional subscripts u and 1 respectively 1 33

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Energy Balance The energy balance around system A yields l[ f ( t ~,, ) }1w,1+IQ,l]l al[; ( t ~,, ) }1w l+~ l]+[l(w ),HJol ] j ( 3 1 Even under steady-state flow conditions, some parts of t h e system, such as the surface of a rotating shaft of any pump do the work against the surroundings, or continuously gener ate electric charges which are discharied to the surround ings. This leads to the work l oss l(w x ) 0 which will be trans formed into thermal ener{? and be trans erred to the surro~nd ings as heat. The term I( W x ) 0 1 therefore can be combined with the heat loss IQol, thereby constituting the total heat loss to the surroundings IQ o w I ; thus, This renders it possible to rewrite Eq (3) as l [ f ( t ) }1w,1+10,l] l a l [; ( t ~,n, J}1w l+IQ l ] +~o w ll ( 4 1 Note that the energy content of the isolated overall system remains invariant regardless of whether the analysis for sys tem A is under steady-state or unsteady-state flow conditions Entropy Balance The principle of the increase of entropy which is a maniFig u re 2. Schematic diagram of a steady-state thermal mixing system wher e a s tream of water at 3 7 3 Kand latm enterin g th e syst e m at th e rate of 0.5 kg-s 1 is mixed adiabatically and isobaricall y with another stream of water at 273 Kand 1 atm enterin g th e system at th e rate of 0 5 kg s 1 ; the resultant stream of water exits from the s y stem at the rate of 1.0 kg s 1 at 1 atm and 323 K resulting from th e energy balance that yields {(0 5 X 1.0 X 3 7 3 + 0 5 X 1.0 X 2 7 3) / {(0.5 + 0.5) X 1.0]}. 1 1 3 211 134 Stream 1 Hp 373 K Stream 2 Hp, 273 K .. festation of the second law of thermodynamics, states : "The entropy of an isolated system increases or in the limit re mains constant." 1 2 1 6 l Consequently, ( dS J ~O dt i s o The above equation can be rewritten a s 1 2 1 ( 11s) ~ o I S O (5 ) In this expression, subscript iso stands for the isolated sys tem The overall system depicted in Figure I is one such sys tem as previously indicated: It encompasses system A and its surroundings It is often convenient to transform Eq (5) into an equality by introducing a nonnegative quantity cr, defin ing the rate of entropy creation in the isolated overall system; this gives rise to ( 11s) = cr I SO (6 ) By considering all the quantities that lead to the change in entropy, we obtain ( 11s) = cr I S O (7 ) As indicated in connection with the energy balance IQ owl in the above expression includes the work loss l(w x ) 0 1 as well as the heat loss IQol to the surroundings. Available Energy Balance Combining the energy balance Eq. (4) and the entropy creation, Eq. (7) gives rise to Surroundings (T 0 P) Mixer Output H 2 0, 325 K C h e mi c al En g ine e rin g Educati o n

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{ f [ f (~-T oY), Hl w ,l+I Q,I ( I-;: ,] ] ) 18 1 ={; [ f (~-ToY), l +[ l w,l+fl, 1[ 1-;.:,]])+T o In light of the aforementioned d e finition s of p and y, term (P-T 0 y) in the above equation h as a connotation of the ava il ab l e energy of molar species, for which sy mbol E i s coined; it i s defined as the partial molar exe r gy Thus E=P-Tor Henc e, Eq. (8) ca n be rewritt e n as (9) {[ f [ f ''"' l] +[ l w,l+fl, i[ i-;: J ] } 1 10 1 =h [ f '' J J +[lw l+fl ,i( 1-;:,J]}+To 0 Th e qu a ntitie s in the brace on the left-hand side of Eq. ( 10 ) have an implication of the total available e nerg y input to sys t e m A Not e that they are not eq u al to th e quantitie s in th e brace o n the right-hand s ide of Eq. (10) that have an implica tion of the total ava il ab l e energy ex iting from the system. Their difference, T o cr signifies th e avai l able energy di ss p a ted by a ll type s of irrever si bility which i s transferred as thermal energy or heat from th e sys t e m to it s s urroundin gs und e r the environmental conditions, as e laborated ear li e r The partial molar enthalpy relative to the dead state, p in Eq. ( 4 ), th e partial molar entropy relative to the dead s tate y, in Eq (7) and the partial molar exe rgy relative to th e dead s tat e, E, in Eq (10) can b e es timated from the follow in g equations. 11 11 1 7 231 ( 11 ) ( 12 ) ( 1 3 ) Man y of their val u es can also b e found in vario u s sources. 111 1 7. 22. 23 ) Sp rin g 2006 THE MIXER EXAMPLE This illu s tration is ba se d on an extremely s imple examp l e It i s well s uited how eve r for effec tivel y conveying the main them e of th e current contribution This example i s an exten s ion of th e well-known o n e 13 2 1 1 in which: no work or h ea t i s transferred from th e sys t e m of co n ce rn to other sys t e m s and v i ce versa; no work or h eat i s lo st from the sys tem to it s s ur roundings; no m ov in g m ec hani ca l part s a re visib l e on the sys t e m ; a nd no c h a n ges in th e chemical compositions of the s tr ea m s pa ss ing throu g h the sys tem are detectable Never thel ess, s imply mixing two s tream s of water at different tem p e ratur es internally lead s to s i g nificant reduction of the avail ab l e e n ergy (exe r gy) of the sys tem. F i g u re 2 illustrates the sys t e m which i s a s t ea d y s tate th e rmal-mixing device or s impl y the mix e r ." Mass Balance Th e t erm, L,M e.1, in the m ass balance e quation Eq. ( 1 ), e .l va ni s h for th e mi xe r ; thu s (14 ) Since M e .u = 1. 0 kg -s1 a nd L,M i =0 .5 +0.5= 1.0 kg s1 we h ave M e. u L,M i = 1 .01 .0= 0 kgs 1 (15) As expec ted th e m ass i s conserved in th e mixer a nd it s s urroundin gs collectively constituting the i s olated overall sys t e m : Water entering the mixer from it s s urroundin gs, b a l a n ces out exactly th e water exi tin g from the mix e r to it s s urroundin gs, M e. u. Energy Balance The terms, I, (Pn) e d I, (Pn) e l IWd, I W2I, IQd IQ 2 I, and e d e. l IQo w l in the energy balance equation, Eq ( 4) vanish when applied to the mixer ; thu s, On the basis of ma ss flow M, in s t ea d of molar flow n the t er m s in th e a bo ve ex pr essio n are evaluated as 1 35

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The first law of thermodynamics teaches that energy is always conserved in an isolated (or closed) system ; it is neither created nor destroyed by any process system or phenomenon .51 In contrast, the available energy analysis, which is the combination of the first and second laws of thermodynamics, indicates that in the real world the available energy is never conserved .... ( PM) =(25.0)(!.0)=25 0 kcals 1 in which e u = o+( 50.025 .o)( 1.o)+0= 25.0 kcal kg1 and si milarl y I,(PM); =(-25.0)( 0.5)+(75 0)( 0.5)= 25 0 kcals1 1 Consequently, (PM) I, (PM) =25.0-25.0=0 kcals 1 e u 1 ( 17 ) Obviou s ly, the energy in the mi xer and its surroundings co ll ectively co nstituting the i so lated overall system-remains unchanged ; energy i s conserved, i.e., never consumed. The energy entering into the mixer from it s surroundings with the flow of water, balances out the e n ergy exiting from the mixer to its surround ings with the flow of water, (PM) Naturally, the first-law e u eff iciency of the mixer in tenns of energy conservation i s (25 0/25.0) or 100.0%. Entropy Balance The tenn s, and IQ ow 1 /T O in the expression for entropy creation, Eq. (7), vanish when applied to the mixer and its surroundings, i.e., to the isolated overall system; thu s, ( 18 ) 136 On the basis of ma ss flow M in s tead of molar flow n the tenn s in the right-hand side of the above expression are evalu ated as (y M) =(0 .08 0)(1.0)=0 .08 kcal s1 -K1 e u in which T p (a J ( Y) =Yo+ I ~dT I T ...:!_ dP e, u T aT p To P o ( 323] 1 1 =0 +l ln -0=0.080 kcal-kg K 298 and similarly L, ( yM); =(-0.088)( 0.5)+( 0.224 )( 0 5)=0.068 kcal s 1 K 1 As a re s ult we have ( L'lS) =a I SO =(yM) I_ (yM) e,u 1 i =0.012 kcals 1 K1 or, equivalently expressed as the most diffused fonn of ther mal energy under the environmental conditions, T 0 (L'ls) =T 0 a IS O =(298)(0.012) =3.576 kcals 1 -K 1 (19) Thi s ascertains that the entropy change of the isolated over all system, accompanying whatever process or phenomenon is occurring in the mixer, is de s tined to be nonnegative. Available Energy Balance The tenns Chemica l Engineering Education

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and IQ 2 I( 1 T 0/T m 2 ), in the available energy balance equa tion Eq ( 10 ), vanis h w hen applied to the mixer ; thu s, I, (En) =(En) +(T 0 cr ) or (En) I, (En) = -(T 0 cr) (20) 1 e ,u e u 1 On the ba s i s of ma ss flow M in s tead of molar flow n the terms in the above expression are evaluated as (EM) =(1.160 ))(!.0)= 1.160 k ca s 1 e u in which ( E)e u =(P) e u T o( 'Y ) e, u =( 25.0)-( 298)( 0 .0 88)= 1.160 kcal kg I a nd s imilarl y 2, ( EM)i =( 1.224 )( 0.5)+( 8 248)( 0 5)= 4.736 kcal s1 Hence (E M) 2, (EM) =l.160-4.7 36=-3 576kcal s1 =-(T 0 cr ) (2 1 ) e, u 1 i Note that Eq. (21) i s totally unlik e Eq s ( 15 ) a nd (17 ): Exergy i s not conserved. No work i s perform e d on the s urroundin gs by water passing through the mixer and no heat i s lo s t to the s urrounding s from water pa ss in g through the mixer In fact, it i s even ass um ed that the flow of water doe s not even en co unt er any friction during th e pa ssage through the mi xe r Neverthe l ess the availab l e energy (exe r gy) entering into the mixer from it s s urroundin gs with the flow of water, doe s not balance with the avai l ab l e energy ( exergy ) exiting from the mixer to its s urrounding s with the flow of water, (EM) e u In fact, it decrease s, the r eby correct l y r e flecting the irrever s ibility of the th e rmal mixing of two water streams inside the mixer. Th e difference s i g nifi es the di ss ipation of available e ner gy, eva lu ated b y Eq. (21) as -3.576 kcal s1 : Availab l e energy (exe rgy ) is a l ways consumed or dis s ipated in th e real world. Naturally thi s di ss ipation of avai l ab l e energy is the only s ource of the entropy incre ase or creation in the i s olated overall sys tem whose thermal equivalent i s eva lu ated by Eq. (19) as + 3 .576 kcal s 1 In esse nc e th e energy of wa ter s tream s "ava ilable to perform u se ful work i s lo s t to its s ur rou ndin gs in the mo s t diffused form-therma l energy under environmen t a l co ndition s -which i s totally unavailable to do any work This results in entropy c r eatio n in th e isola t ed overSprin g 2006 all sys t e m which ca n b e the uni ve r se it se lf In drastic co n tra s t to the first -l aw efficiency, th e seco nd-law efficiency in term s of ava ilable energy (exe r gy) co n se rvation i s merely ( 1.160/4. 7361 ) or 24.5 % Now s uppo se that th e mix e r i s ex t e rnall y h eated at the rate I Q il, of 50 kcals 1 b y a he a t e r atthe temperature, T m of 800 K Nat u rally, the temperature a nd the corresponding energy (e nth a lp y) of water exiting from the mixer increase to 373 K and [ I.O X ( 100--25 ) ] X 1.0 kcal s 1 i.e. 75 kcal s1 respec ti ve l y The energy balanc e around the mixer yields th e fir s law efficie n cy of [75/(25+50)] X 100 % or 100 % thereby in dicating that it i s not affected b y ex ternal heating. The con comitant change in the ava ilable energy (exe rg y) of water exiting from the mixer i s from 1.160 kcal s1 to [75-(298 X 0.224 ) ] X 1.0 kcal 1 i e 8.248 k ca l 1 This i s obviously an increa se rather than a decrea se w ithout ex t e rn a l he at in g, thu s indicating the po ss ibility of e nh a n cing the mixer 's sec ond-law efficiency In reality h owever, the opposite i s the case: s impl y adding external he a tin g reduces the sec ond-law efficie nc y from 24.5 % to { 8 2 4 8/[4. 7 36 +50 X ( l-298/800)]} X 100 % i.e., 22 8 % R egar din g th e first law Seider et at.,1 2 1 1 s tate ," .. it can not eve n g i ve a clue as to whet h er e n ergy i s bein g u se d efficiently .... Moreov e r according to R e i s tad and Ga gg ioli ,12 4 1 Th e seco nd-law eff i ciency is th e perfor mance parameter which indicate s the true thermodynamic performance of the sys t e m. CONCLUDING REMARKS With the aid of a deceptively si mpl e examp l e it ha s been un eq ui voca ll y d e mon s t ra t ed th a t e n ergy is conserved, i.e ., n eve r co n s umed ; w hat i s a lw ays co n s umed or di ss ipated i s available e nerg y (exe r gy) which is the esse n ce of this bri ef co ntributi on. Thi s s imple exa mple also s uccinct l y indicate s that an attempt to rigorou s l y assess the s u stai nability of any proces s or sys tem s hould be based firm l y upon the thermo d y n a mic s in general, and the eva lu atio n of the sys t em's sec ondl aw efficiency ba se d on avai l able energy ( exergy ), in p ar ticular as practiced in th e EU co mmunity 1 25 1 a nd th e Canton of G e ne va in Switzerl a nd .'2 61 ACKNOWLEDGMENT Thi s work was s upport e d b y U.S. D epartme nt of Energy under Contract DEFG 36OIID14126 NOMENCLATURE A s yste m A cp s pecific h eat J mol K M ma s s flow rate in cludi n g both co n vec ti ve and diffu s ional flow s, kg s 1 Mw m o l ec u lar we i g ht g m o 1 1 N molar flow rate includin g both convective and diffu1 3 7

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siona l flows mol s 1 P pressure atm IQ al heat loss to the environment per unit time, J s 1 or kcal s l IQ owl total h eat l oss to the environment per unit time J s 1 or kcal s 1 IQil heat transmitted from system Ml to system A per unit time J s 1 or kcal s 1 IQ 2 1 heat transmitted from system A to system M2 per unit time, J s 1 or kcal s 1 S entropy, J K 1 s partial molar entropy, J mo1 1 K 1 T temperature of system A, K Tm 1 temperature of system Ml, K T '" 2 temperature of system M2 K v volume, m 3 IW al work lost to the surroundings per unit time, J 1 or kcal s I IW 1 I work supplied from system NI to system A per unit time J s 1 or kcal s 1 IW 2 1 work supplied from system N2 to system A per unit time J 1 or kcal s 1 work lo s t to the surroundings exce pt that due to expansion of the boundary of sys tem A per unit time, J s 1 or kcal 1 Greek letters partial molar enthalpy relative to the dead state, J mol 1 or kcal kg 1 ~o partial molar chemical enthalpy, J mol 1 or kcal kg 1 partial molar exergy J mo] 1 or kcal kg 1 0 partial molar chemical exergy, J mo1 1 or kcal kg 1 y partial molar entropy relative to the dead state, J mol 1 k 1 or kcal kg 1 -K 1 y O partial molar chemical entropy J mol 1 k 1 or kcal kg 1 -K 1 cr created entropy per unit time J. sec 1 k 1 or kcal sec 1 -K 1 Subscripts 0 dead state e,u useful output streams input streams iso isolated system k material s pecie s leakage Superscript 0 standard state 1 38 REFERENCES I. Fanchi, J.R. Energy in the 2 1 s t Cent ur y, World Scientific Publishing Company (2005) 2. Denbi g h K .G., The Second-Law Efficiency of Chemical Proce sses, Chem.Engr. S c i 6 I ( 1956 ) 3 Gaggioli R.A Principle s of Thermodynamics, in Th ermodynam i cs : Se co nd La w Anal ys is, ACS Symposium Series 122 Ed R.A. Gaggioli, American Chemical Society, Washington D.C (1980) 4. K y le B.G., Chemi c al and Pr ocess Thermod y nam cs, Prentice Hall : New Jersey ( 1 999) 5. Stanley, I.S. Chemical and En g ine e rin g Th e rmodynami cs, John Wiley & Sons Inc. 3rd Ed. ( I 999) 6 Keenan J.H. Availability and Irr eversibi lit y in Th e rmod ynamics Briti s h J. of App. Phy s ics 2 1 83 ( 195 I ) 7. Hatsopoulo s, G.N. and J H. Keenan Prin cip le s of General Thermo dynamics, Wiley New York ( 1965 ) 8. Denbi g h, K.G. The Prin c ipl es of Chemical Equilibrium, Cambridge University Pr ess (I 966) 9 Szargut, J. and Petela R., Egzer g ia Warezawa, l 965 ( in Polish ) 10. Szargut, J ., D.R. Morris and F.R Steward, Exergy Ana l y sis of Ther mal Chemi c al and Metallurgi c al Pr ocesses, Hemispher e Publishing Corporation ( 1988 ) II. Fan L.T., J.H. Shieh Thermodynamica ll y Based Analysis and Syn thesi s of Chemical Proce ss Systems," Energy, 5, 955 ( 1980 ) 12. Petit, P.J R .A. Gaggioli Second Law Proc ed ure s for Evaluating Pro cesses," in Thermod y namics: Se co nd Law Analysis, ACS Symposium Series 122 Ed. R.A. Gaggioli American Chemical Society Washing ton D.C ( 1980 ) 13. Sussman M. Y., Availability ( Exer gy) Anal ys is A Self In struction Manual, Tuft s U niv ersity (I 980) 14. Fan L.T., J.H. Shieh T. I s himi and T. Graham "Prac ti ca l Applica tion s of Proc ess Sy s t e m s Engineering to Energy and Re so urce Con servation and Management, Comp. Chem. En g 7, 793 ( 1983 ) 15. Kenne y, W .F., Energy Conserva ti on in the Pr ocess Indu stries, Aca demic Pr ess, Inc. ( I 984) 16. K ee nan J H ., Therm o dynami cs, Wiley New York ( I 941 ) 17. Gag g ioli R.A Thermodynami cs and the Non-Equilibrium System Ph.D Thesis University of Wi sco n s in ( 1961 ) 18. Reist ad, G.M. Ava il abi li ty: Concepts and Appli c ations, Ph.D. Thesis, University of Wisconsin ( I 970) 19. Deben ede tti P.G ., "The Thennodynamic Fundamentals of Exergy Ch e m. Eng. Ed ., XVIII, I 16 ( 1 984) 20 Paulu s, D.M. a nd R A. Gaggioli, The Dead State According to the Avail a bl e Energy of Gibbs ," American So c iety of Mechanical Engi n ee rs Advanced Energ y Systems Divisi on ( Publi cation) AES, v 40 (2000) 2 1 Seider W.D. J D. Seade r and D.R. Lewin Produ c t and Pr ocess D e s i gn Principles John Wiley and Sons (2004) 22 lshimi T., J.H. Shieh a nd L.T. Fan "T hermodynamic Ana l ysis of a Bioma ss Pyrol ysis Pro cess," in Wood and Agri c ultural R es idu es E .J Soltes ed., Academic Press, New York ( 198 3) 23. Yantov sk ii E.I. En e r gy and Exe1g y Currents NOVA Science Pub I i s her s ( 1 994) 24. Reistad G.M. and R .A. Gaggioli Availab l e-Energy Costing ," in Th e rm ody nami cs: Se c ond Law Analysis, ACS Symposium Serie s 122 Ed R.A. Gaggioli American Chemical Society Washington D.C (1980) 25. Lowex News "Low Exergy Guidebook in 2004 Offers Ba s ic Knowl e d ge of H ea tin g a nd Coo lin g Systems for Sustainab l e Buildin gs," 8 D ece mb er (2003) 26 Lima Ricard o a nd J. Da Silva, Ex e r g i e, Ecole P o lytechniqu e Federale D e Lau sanne Geneve-Mai (2005) (i n French) 0 Chemical Engineerin g Edu c ation

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( The Next Millennium in ChE Inside the Cell co ntinu ed from pa ge 131 com binati on of rati ona l design and sc r eening of mutant librari es w ill b e us e d t o cre ate g r ee n fluor esce nt pr ote in s w ith impr ove d photophysi ca / pr o p e rti es. 9 Genetically Targetable Labels for Light and EM R oger Y. Tsien Ph.D ., prin c ip a l in ve stigator, University of California San Di ego A team from the University of Calif o rnia and th e Uni ve r s i ty of Illin o i s plans a se ri es of appr o a c h es t o gene r a t e fluores ce nt prot e in s w ith in c r eased photos/ability and hi g her quantum y i e ld t o ex plor e quantum dot co n s tru c ti on a nd tar ge tin g and t o furth e r develop tetra cys teine l abeling te c hn i ques for li gh t and e l ect ron mi c r osco p y. Th e t ea m 's plan s also includ e ex ploring gene ri ca ll y tar ge t a bl e lab e l s w ith lon g exci t e d state lif e tim es bas e d on lanthanid e and transiti o n m e tal lumin esce n ce as we ll as dire c t e d evo luti o n of fluores ce nt pr o t e in s to impr ove th eir ph o t o ph ys i c al prop e rti es A maj o r go al of thi s t ea m is to enab l e dire c t v isualizati on in the e l ectron mi c r osco p e of the s ame mo l ec ul es that ha ve been ta gge d o b served and dynami c all y tra c ked in th e li gh t mi crosc ope Now that br eak through s are under way to provide specific information on th e functionin g and control of organelles a unique opportunity is evo lvin g for chemical engineers to u se thi s mechanistic information to de s i g n new integrated bioc e llular operations and processes. It is lik e ly that excep tion a l progre ss wi ll be made in the n ex t decade to reveal the ph ysical chemical phenomena that govern th e organization and behavior of the biochemical pro cessing unit s within cells. Naturally then n ew concepts of proc ess design will emerge for the chemical/biochemical in dustry throu g h the research efforts of biochemical engi n eers. As this knowled ge becom es ava ilabl e it will be incorporated into the gra duat e -pro gra m cour s es in c h e mical e n gi n eeri n g departments as an enhancement to courses s u c h as systems biolo gy, bio-MEMS biochemical se parations bioproces s engineering and pharma ce uti ca l biotechnology. One ca n ex p ec t a dramatic evo lution in proc ess t ech nolo gy that will b come a n important ca pabilit y for future c h emica l e n gi ne e r s, especially for hi g h-value low-volum e product s Sprin g 2006 ) R E FE R E NC ES: I. Burn s, M.A., B.N John so n S.N Brahma sa ndra K. Handiqu e, J .R. Web s t e r M. Kri s hnan T.S. Sammarco P M Man, D Jones D. H e ld s in ge r C. H. Mastran ge lo a nd D.T. Burke "A n Int egra ted ano lit er D NA Ana l ysis D ev ic e," S c i ence (2 82 ) 484 -487 ( I 998) 2 Yo s hida M K. Tohda and M. Gratz!, Opt i ca l D e t ec tion in M i cro sco pic Domain s 3:Co nfocal Anal ys i s of Fluorescent Amphip hili c Mol ec ule s," Anal. Chem. ( 75 ) 6 1 33 -6140 ( 200 3) 3 Rubart M. "Two photon mi crosco p y of ce ll s a nd ti ss u e, Circ. R es. ( 95 ) I I 54-66 (200 4 ) 4 R eeves, A. R L. P arso n s, J.W. H e ttin ger, and J I. Medford In vivo thr eedimen s i o nal ima g in g of p l ants with optical coherence mi cros co p y," J. Mi c r oscopy ( 208 ) 1 771 89 ( 2002 ) 5. Wabu ye le M B. M C ulh a, G.D Griffin P M. Vialle t a nd T. Vo-Din h N ea r-fi e ld scan nin g opti ca l mi crosc opy for b i oa nal ys i s a t n a nomet e r re so lution Meth ods M o / Bi o l (3 00 ) 437-52 (2 005) 6. Jin T. N. Zh a ng Y Lon g, C.A. Parent a nd P N. De v r eote;_;, Local i za ti o n of the G Prot e in b g Complex in Livin g Cells Durin g C hemot ax i s," S c i e n ce ( 287 ) I 034 (200 0 ) 7. Il ege m s E ., H .M. Pi c k, C. D e lu z, S Kellenberge r and H. Vo ge l Noninvasive Ima g in g of 5-HT3 Rec e ptor Trafficking in Li ve Ce ll s From Bio sy nthe s i s T o Endocyto s i s," J. Bi o l Chem. (2 79 ) 53346-53352 (2 004 ) 8. M i yaw aki A and R Y. T s i en, Monitoring prot e in conforma ti ons and interact i ons b y flu oresce n ce r eso nan ce energy transfer b e tween mu tant s of g r een fluor esce nt protein ," Meth ods En zy mol. (327) 472-500 (2000) 9. Zha n g J. R E Campbell, A.Y. Ting and R.Y. Tsien, "Crea tin g ne w fluor esce nt prob es for ce ll biolo gy," Na tur e R eview M o /. Ce ll Bi ol., ( 12 ) 9061 8 D ec 3 (2 002 ) 10. Y e, K ., and J S. Schultz Gen e ti c e n g in ee rin g of a n a ll o s t er ic ba sed g lu cose indi ca tor protein for co ntinuou s g lu cose monitoring b y fluo re sce nc e resonance e n e r gy tran s fer ," Anal. Chem. ( 75 ) 345 1-3459 (2 003 ) 11. F e hr M. W .B Frommer a n d S. La l o nd e "V i s uali za ti on o f m a lt ose upt ake in li v in g yeas t ce ll s by fluorescent n a n ose n so r s, Pr oc. Natl. Acad. Sci. USA ( 99 ) 9846-51 (2 002 ) 1 2. Buck S M. Y.L. Koo E. Park H X u M A. Philb e rt M A. Brasuel R. K o p e lman Optochemi ca l n a n ose n s or PEBBLEs : phot o nic ex plor e r s for bioanal ys i s wi th biolo g i ca ll y locali ze d e mb edd in g C urr ent Opini o n in Chem. Bi o l ( 8 ) 5 40--5 46 (2 004 ) 13. Tall ey, C.E L. Ju si n sk i C.W. H o ll ars, S.M. L a n e, and T. Hu se r, In trac e llular pH Sen s ors Ba se d o n Surface-Enhanced R a man Scatter in g," Ana l Chem. ( 76 ) 7064-7068 (2 004) 1 4 Wei ss l e der R C. Tung U. Mahmood, and A. Bo g danov Jr. In vivo im agi n g of tumor s w ith protea se ac ti va t e d near-infrared fluor esce nt probe s ," Nat ur e Bi o t ec hn o l ogy ( 17 ) 375 ( 19 99) 15. Ei l s, R ., a nd C. Atha l e "C omputational ima g in g in ce ll biolo gy, J. Cell Bi o l ( 161 ) 477 (2 003 ) 16. G e rli c h D J. Matte s, and R Ei l s, Quantitative motion analys i s and v i s u a li za tion of ce llular s tru ctu r es ," Methods ( 29 ) 31 3 (2003) 17 S l e p c h enko, B.M. J C. Schaff I. Macara, and L.M. Lo ew, Quantita tiv e ce ll biolo gy w ith th e Virtual Ce ll ," Tr e nd s i n Cell Bi o l. ( 13 ) 570 (2 00 3) 1 8. Ru eden, C., K.W. E li ce iri a nd J G. Whit e, Vi s Bio: A Compu t a ti o n al Tool for Visua l izatio n of M ultidim en s ion a l Biolo g i ca l Im age Data ," Tra ffic ( 5 ) 411--41 7 (2 004 ) 0 1 39

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[3 5 4 class and home problems ) r The object of this column i s to enhance our readers' collections of intere st in g and novel prob lems in chemical engineering. Problems of the type that can be u sed to motivate the st udent by presenting a particular principle in class, or in a new light, or that can be assigned as a novel home problem are requested, as well as those that are more traditional in nature and that eluci date difficult concepts. Manuscripts should not exceed 14 double -s paced pages and should be accompanied by the originals of any figures or photographs. Please s ubmit them to Professor James 0. Wilkes (e-mail: wiLkes@umich.edu), Chemical Engineering Department University of Michigan Ann Arbor, MI 48109-2136. 'GAS PERMEATION COMPUTATIONS WITH MATHEMATICA HousAM Brnous National Institute of Applied Sciences and Technology 1080 Tunis Tunisia G as se paration s u s ing membranes have received increased attention by the sc ientific and industrial community. This technique is now at a mature stage and can compete with more common techniques used in the petrochemical industry such as cryogenic separation, gas ab sorption, and pressure swing adsorption. The nonporous mem branes can be organic or inorganic. They are classified ac cording to their thermal and chemical s tability as well as their selectivity to different gases. The mechanism of separation i s based on the differences in the dissolution and diffusion of gases in the nonporous membrane. The separation of hydro gen from other gases such as carbon dioxide and carbon mon oxide in sy ngas plants is a very important industrial applica tion of thi s technique Acid gas (CO 2 and H 2 S) elimination from natural gas is another application of membrane separa tions. Very often one i s confronted with the separation of multicomponent mixtures Thus, we consider a hypothetical ternary mixture, in the first part of the paper to show how one can obtain the permeate and reject compositions as well as the membrane area. SEPARATION OF A TERNARY MIXTURE A ternary feed mixture ha s the following composition and flow rate : xrA=0.25, xrn=0.55, xrc=0.2 and qr=l.0xl0 4 cm 3 (ST P )/s Since the stage cut, defined as the fraction of the feed al l owed to permeate i s 8=0.25, the permeate flow rate, q is p equal to 0.25 X 10 4 cm3(STP)/s The permeabilities, expressed in cm 3 (STP) cm/(s cm 2 cmHg), of components A, B and C Hausam B i nous is a full-time faculty mem ber at the National Institute of Applied Sci ences and Technology in Tunis He earned a Diplome d 'i ng(mieur in biotechnology from the Ecole des Mines de Paris and a Ph D. in chemical engineering from the University of California at Davis His research inter ests include the applications of computers in chemical engineering. Copyright ChE Division of ASEE 2006 /40 Chemical Engin ee rin g Education

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are equal to P~ =200 x l0 1 o P ~ =50 x !O IO an d P ~ =25 x !O-IO_ Thi s mixtur e i s to be se parat ed b y a membrane wi th a thi ck ne ss t=2.54 X ]0 3 c m Pr ess ure s on the feed and permeat e s id es are p h =300 c mH g and p 1 = 30 c mH g We wi ll u se the co pl etemixin g model to co mpute th e permeate a nd th e r eject compositions as well as the membrane area. Th e thr ee rate of-permeation equations are: p : qpYpi=_!_Am(PhXoi-P!YPi) for i=l 2 3 (I ) t The three mat eria l balan ces eq u a ti ons written for compo n e nt s A, B and C are: I 0 XOi= 1-eXfi -1-eYP i for i=l 2 ,3 ( 2 ) Finally, we hav e an additional r e lation th a t is th e s umm a tion rule for mole fractions: ( 3 ) Equations I throu g h 3 are lab e l e d rate, matb a l ance a nd s ummation respectively. W e n eed to e nt e r th ese e qu a ti o n s in the Mathemati ca not e book 1 21 and ca ll FindRoot as follows: FindRoot[ {ratel, rate2, rate3, matbalancel, matbalance2, matbalance3, summationl}, {y, A, 0.2}, {y 0.2}, {y c 0 2 } {A .. 10 A 6 } { X O A 0 2 } { X O B 0 2 } { x 0 c o 2 } J (a) complete mixin g model ( c) countercun-ent flow FindRo o t u ses diff ere nt root sea rch te c hnique s th at ca n be se l ec t e d b y the u se r. If one s p ec ifie s only one starting va lu e of the unkn ow n FindRoot searc h e s for a so lution u si n g New ton methods. If th e u s er specifies t wo s tartin g val u es, FindRoot u ses a var i a nt of th e seca nt m et hod which do es not r e quir e the comp ut atio n of derivative s. All thi s i s handled int erna ll y by Math e matica, making the so lution of comp l ex sys t e m s of nonlinear a l ge brai c eq uation s very easy. We ge t the follow in g so lution for th e p e rmeat e and reject co mpo s ition s a nd th e membrane area l abeled A : m { Y PA 0 4 5 5 2 8 1 Y PB 0 4 5 0 2 8 6 Y pc 0 0 944 33 5, A m 3 5 4176X l 0 6 X 0 A 0 1 81 57 3 X 08 Q 5 8 3 2 3 8 X OC Q 2 3 518 9 } wh i c h i s in agree m e nt with re s ult s u si n g a tedious iterative t ec hniqu e 11 1 ENRICHMENT OF AIR IN OXYGEN USING MEMBRANE PERMEATION In this sec tion we present the s tud y of th e enrichment of oxyge n in air u sing a s ingle-stage membrane modul e. Thi s problem h as been tr eated first by Walawender a nd Stern 1 3 1 a nd later b y Geankoplis. 111 The binary mi xt ure A (oxyge n ) a nd B ( nitro ge n ) ha s a n id ea l s e par a tion factor, th e ratio of th e perm ea bilitie s of the two s p ec ie s, a = 10 Th e perme ability of oxygen i s P ~ =500 X 10 10 c m 3 (S TP ) c m/ (s cm 2 c mH g) Th e membran e i s more permeabl e to oxygen and has 8 q r Yr (1-8) q r xo ( b ) cross flow 8 q r Yr q r xr ~ ( l-0 ) q r xo dA m ( d ) co-cun-ent flow Figure 1. Flow patterns Sprin g 2006 1 41

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a thickne ss t=2.54 X 10 3 c m. The stage cut, 8, i s se t equal to 0.2 The values of the pre ss ure s in the feed and permeate sides chosen by Geankopli s 111 are p h= l90 cmHg and p 1 =19 cmHg, which give a ratio of pressure s, r, equal to I 0. The feed rate and composition are given by: xrA=0.209, xrn=0.791 and q r =I.0 X 10 6 cm 3 (S TP)/ s. The different flow p atte rn s, s hown in Figure 1 ( previou s page ) and considered in this study, are co mpl ete mixing cross flow countercurrent flow and co-current flow Calculations for each flow pattern will be presented in a se parate s ub section. 1. Complete-Mix i ng Cas e The permeate mole fraction, y i s the solution of the fol P lowing quadratic equation: a [xo( ~}r] (1-x 0 )-(:~ ) 1yr) (4) where the reject composition, x 0 i s g iven by th e ma ss bal ance: Xf8y X p ol-8 (5) We also define O'. and r by O'. = P~/ P~ a nd r=p/pr The m e mbrane area i s then obtained u s ing Equation (6): (6) For our particular probl e m we find the fo l lowin g re s u l t s using Mathematica: y P =0 .5067, x 0 =0.1346, and A 0 1 = 3.228 X 10 8 cm 2 These r es ult s are in agreement with tho se found by Geankopl i s. 1 ll 2. Cross-Flow Case The local permeate rates over a differential membrane area are given by In addition we can derive Equation (9) from total and com ponent ma ss balance s : 142 ydq =d( q x) (9) These three governing equations are so lved sim ultaneou s ly using the Mathematica built-in function called NDSolve. The following boundary conditions are used: qlAm=O=qr xlAm = O=xrA and YIAm = o=Yp; where Yri is obtained b y so l v ing the quadratic equation ( IO ) The command used in the notebook to solve the system of ODE s is: myODEsoln [ Q ] NDSolve[ { y[A m ] D[q[A], {A m l}]== D [q [AJ x [A m ] {A m l m } J -y[A m ] D[q[A m ], {A m ,l}]== P' A/ t (p h x[A m ] P 1 Y [AJ ) -(1y [A m ]) D[q[A m ], {A m ,1}]== P' 8 /t+(p h (lx[A m ]) p 1 (1y[A m ])), x [ 0] == x f y[0] == y Pi 'q[0] == q f {x[A J y [A m ] q [A J } {A m 0, Q }] We u se FindRoot to get the tota l membrane area. In fact, we must satisfy th e following condition: 8=0 .2 where the stage cut, 8, is given by 8= ( q ( ql e nd)/qr. The Mathematica command is written as follows: qend[O_?NumericQ] : =Flatten[(q[A m ] / myODEsoln [ Q ]) / .A m 0] A sel = FindRoot [ ( q f qend [ 0] ) / q f == 8, {n 2 l0AB,3 l0AB}, Maxiterations l000]; The final result is a membrane area and a reject composi tion equal to: A 01 =2.899 X 10 8 cm 2 and x 0 =0.1190. A compo nent balance Sy +(18 )x 0 =x can be used to obtain the perP fA meate mole fraction and we find that y =0 .5688. Our approach p gives s imilar result s as those given b y Geankoplis l 1 J but is far le ss tediou s and more accurate. We can check our results by inte gra ting y(Am) for Am varying from Oto A 0 1 achieved with the command: Integrate[First[y[AJ / .myODEsoln[O / A sel ] J / A m area' {area, 0 Q / A sel } ] / Q / A sel We get yP=0.5634, a value in agreement with the previou s result. Since numerical integration i s u se d the l a t e r value of Chemica l E n gineering Ed u cation

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y i s les s exac t. In Fi g ure 2, we plot the mole fraction in the p permeat e and feed s ide s in th e membran e modul e Similar figures can be easily drawn for th e other flow p a ttern s u s in g the graphical capabilities of Mathematica. Figure 2 clearly s hows that the oxygen mole fr ac tion in the feed s ide of the module varies from the inlet value, x r =0.209 to the r e j ec t value, x 0 =0 l l 90 3 Countercurrent Flow Case The flow diagram for th e co untercurr e nt-flow patt ern i s s hown in Figure 1. Both s tr ea m s are in plu g flow. Th e t wo governing equations have been d er i ve d b y Oi s hi et a / ., 141 a nd Walawender and Stern 1 3 1 : [ --9..J ~= ( ~ J {( 1x )a ( r x-y )-x [r( 1x )-( 1y ) ]} P1PB dA m y-xo ( I I ) [ %'. J ~= ( ~ J {( 1-y )a (rx-y )-y[r( 1 -x )-( 1y )]} P1PB dAm X Xo (12 ) where q 0 =(10 )qr The followin g boundary conditions xlA o = xo and YIA o =Y; m m are used where Y ; i s the solution of th e quadratic e quation : a [xo( f } ;] (1-x 0 )( :~ )i-y;) ( 1 3) We use L Hopital 's rule to compute th e derivative s atA "' =0 because they becom e indet e rminate when x = x 0 This i s p er formed as fo ll ow s: Mole fractions 0 6 0.5 0.4 0 .3 0 2 S x l 0 7 l x l o' I. S x l o' 2 x l o' 2.S x l o' Figure 2. Mole fract ion s of reject a nd permeate. Sprin g 2006 (14 ) ( ~ J =-1 [a (rxo-Y;)(xo Y;)l dAm Am = O [ q o'. J Y; P1Ps ( 15 ) The se two differential equations can be so lved s imu l ta n eo u s l y u s in g NDSolve We enter the equations using an If s tatem e nt to tak e into account the d er ivative expression when A O: m eql [ a ] : = D [x [A m ) { A m 1}) == If [A m == 0 Evaluate [ ( p 1 P' 8 ) / ( q 0 t ) a ( xo p h/ p 1 yi ) ( xoyi) / yi / t -> 2 54 l 0 A-3 / P h > 190 / P 1 -> 19 / a > 10 / P' 8 > 5 0 l0 A-1 0 / > 8 1 0 A5 / .x o a), Evaluate[ ( p 1 P' a )/( q o t ) ( x[A m ] y[A m ) )/ ( y[A m ] xo ) ( ( 1x[A m ) ) a ( p h / p l x[A m ] y[A m ] ) x[A m ) ( p h/ p l ( 1-x[A m ) ) ( 1-y[Am) ))) / t> 2 .54 l 0 A-3 / P h -> 1 90 / P 1 -> 19 / a > 1 0 / P 8 > 5 0 l 0 A-1 0/ q 0 > 8 1 0A5 / .x o a)) Since the value of the reject mole fraction x 0 and the to t al area, A "' are unknown we use FindRoot to solve for these two unknown s so that the mole fraction of oxygen in the feed i s 0 209 and th a t the m a t e rial balance for co mponent A is ve rifi ed : Following the tr ea tm e nt of Wal awe nder and Stern ,13 1 we se t th e area equal to zero at the outlet of the gas separation module. Thus, th e s ign of the membrane area obtained using thi s approach i s negative and mu s t be reve r se d We get the fo llowin g re s ult s : A 1 =2.859 X 10 8 cm 2 y =0.5763 and s o p x 0 =0. l l 7 l We find a s mall e r membrane area and reject mole 14 3

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fraction and a higher permeate composition. 4 Co Current-Flow Case The governing equationsC 31 are derived in a similar fashion to the preceding case. ( ~J~=( x-y J{( 1-y )a ( rx-y )-y[r( 1-x )-(1-y )]} P1Ps dAm x-xf (16) ( ~J~=( x-y J{( 1-x )a ( rx-y )-x[r(l-x )-(1-y )]} P1Ps dAm y-xf (17) The following boundary conditions must be used: xi Arn =0 = x Af and YI Arn =0 =Yi. The value of Y; is a solution of the following quadratic equation: (18) Inspection of Equation ( 16) shows that the derivatives are indeterminate when Am 0. We use L'Hopital 's rule to get expressions for the derivatives at Am =0 as follows: (19) ( ~J =-1 [a (rxf-Yi)(xf-Yi)l dAm Am=O (~J Yi P1Ps (20) The value of the total membrane area is found using FindRoot to satisfy the material balance for oxygen: Sy Pl +(1-8)x 0 = xAf The membrane area, permeate com A sa l position, and reject mole fraction are equal to: A 0 1 =2.955 X 10 8 cm 2, y =0.5584 and x 0 =0.1216 p 5. Comparing the Differen t Flow Patterns The membrane areas are equal within I 0 % The smallest membrane area is obtained using the countercurrent flow pattern. The countercurrent case requires a smaller membrane area because the driving force for permeation (the composi144 tion difference between permeate and feed sides) is higher than in the other flow patterns. The complete-mixing model gives the highest membrane area The reject mole fractions and the permeate compositions obtained for the four cases studied show similar trends. The most efficient flow pattern is the countercurrent mode. In fact the order of efficiency is the following : countercurrent flow> cross-flow> co-current flow > complete-mixing model. Reducing membrane area has a major impact on capital investment costs. Thus, the countercurrent flow pattern is the optimal design choice. Other relevant parameters for reducing membrane area are thick ness and permeability of the membrane and operating pres sure, which will affect operating costs as well CONCLUSIONS In this study, we showed how simple Mathematica com mandsc 21 can be used to solve problems that required tedious iterative techniques or complicated programming skills. We present the solutions of two problems proposed by Professor Geankoplis 1 11 We extend this author s work to the counter current and co-current flow patterns. These problems are given to the junior and senior students of the National Institute of Applied Sciences in Tunis as small research projects. The students excel in these type of problems despite the fact that they do not have prior knowledge of Mathematica NOMENCLATURE Am membrane area p; permeability of component i P h feed side pressure P1 permeate side pressure q r feed flow rate q p permeate flow rate q o reject flow rate t membrane thickness r ratio of pressures of feed and permeate sides x n feed mole fraction of component i x 0 reject mole fraction yP permeate mole fraction a separation factor 8 stage cut REFERENCES I. Geankoplis C.J., Transport Pr oces ses and Unit Op era ti ons, 3rd Ed. Prentice Hall, Upper Saddle Riv e r, NJ (1993) (exa mple 13.5-1 page 771 and example 13.4-2 page 767) 2. < http: //1 i bra r y. w o If ram.com / info center/search / ?sea rch results= I ;sea r c h_per so n id= 1536 > 3. Walawender W P and S.A. Stern, Separation Scien ce, 7 5 553-584 ( 1972 ) 4. Oishi J. Y. Matsumura, K. Hi gas hi and C lk e 1. At Energ y So c. Japan 3 ,923 (1961) D Chemical Engineerin g Edu c ation

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