Chemical engineering education ( Journal Site )

Material Information

Chemical engineering education
Alternate Title:
Abbreviated Title:
Chem. eng. educ.
Physical Description:
v. : ill. ; 22-28 cm.
American Society for Engineering Education -- Chemical Engineering Division
Chemical Engineering Division, American Society for Engineering Education
Place of Publication:
Storrs, Conn
Publication Date:
annual[ former 1960-1961]


Subjects / Keywords:
Chemical engineering -- Study and teaching -- Periodicals   ( lcsh )
serial   ( sobekcm )
periodical   ( marcgt )


Chemical abstracts
Additional Physical Form:
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.
General Note:
Title from cover.
General Note:
Place of publication varies: Rochester, N.Y., 1965-1967; Gainesville, Fla., 1968-

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University of Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
oclc - 01151209
lccn - 70013732
issn - 0009-2479
lcc - TP165 .C18
ddc - 660/.2/071
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Full Text

chendad en ring education



-a EF W ATION ................. Awmw A I
Features 0'.
and Teaching
An Experiment in. Combustion (page 2.6j
X64h B.Ter4o4 Avonio M. Wwitore,, S4im M, Senkan in
Rand6m Thoueo Irripostors Rve"hm (pap 220)
pqge 202)
bu 'On synthesig Wd mateAals Wr6cessing (page 228
coni stj I 1i I WaAk4t
-Daniel, E., Rosner
On tbe, NAIM and Conduct of TeeWcW R"mch (page 22)
Jhn P O'Con ne ti
Velping Students Becom Retter Mathematical Mochlm (page,2-54)
A Stroaured, Interview for, $,elootionof GToAuato Students fp4ge 210)
Mrr A, DW, Afwm ZOWe&
A Novel Laboratory Cours& on A4yano ChE, Experiments (page 260)
J,, L4mterbaok S. WNW; 2, Liu, 6-M., Bod, WX Delgasv
Toward Tephnii;4 Vuderstandiog: Pan 2. Elementary. Uvels (page 214)
1, M, 1we
Clas&Mome Problom Stan-Up of a Non-Isodmmal CSTR- Maftmatical Modeling (page 250)
"i M, 'A"-
Process Integration and Industrial Pollution Prevention-
'Merging Theory and ftAcdw, in'Graduate Fducation (pagr142)
Gio'rgw CarwM, DouglasLeVw H. DmnisSpriggs GrqoryA. Cleo'tefisH, J4nws EJZ>w Jr,
SPWkd'FO4W4re 41 Meet the Authors fpag-e 248)

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Chemical Engineering Education
Department of Chemical Engineering
University of Florida Gainesville, FL 32611
PHONE and FAX: 352-392-0861

T. J. Anderson

Phillip C. Wankat

Carole Yocum

James O. Wilkes and Mark A. Burns
University of Michigan
William J. Koros
University of Texas, Austin

E. Dendy Sloan, Jr.
Colorado School of Mines

Gary Poehlein
Georgia Institute of Technology
Klaus Timmerhaus
University of Colorado

Dianne Dorland
University of Minnesota, Duluth
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
David F. Ollis
North Carolina State University
Angelo J. Perna
New Jersey Institute of Technology
Ronald W. Rousseau
Georgia Institute of Technology
Stanley I. Sandler
University of Delaware
Richard C. Seagrave
Iowa State University
M. Sami Selim
Colorado School of Mines
James E. Stice
University of Texas at Austin
Donald R. Woods
McMaster University

Chemical Engineering Education

Volume 31

Number 4

Fall 1997


202 Synergism Between Research and Teaching in Separations,
Phillip C. Wankat


0 210 A Structured Interview for Selection of Graduate Students,
Marc A. Dubi, Mama Zinatelli

> 214 Toward Technical Understanding: Part 2. Elementary Levels,
J. M. Haile

> 222 On the Nature and Conduct of Technical Research,
John P. O'Connell

228 Combustion Synthesis and Materials Processing,
Daniel E. Rosner

236 An Experiment in Combustion,
Keith B. Fordon, Antonio M. Vincitore, Selim M. Senkan

P 242 Process Integration and Industrial Pollution Prevention:
Merging Theory and Practice in Graduate Education,
Giorgio Carta, M. Douglas LeVan, H. Dennis Spriggs,
Gregory A. Cleotelis II, James E. Ryan, Jr.

> 254 Helping Students Become Better Mathematical Modelers:
Pseudosteady-State Approximations,
Annette L. Bunge, Ronald L. Miller

260 A Novel Laboratory Course on Advanced ChE Experiments,
J. Lauterbach, S. White, Z. Liu,
G.M. Bodner, W.N. Delgass

250 Start-Up of a Non-Isothermal CSTR: Mathematical Modeling,
Aziz M. Abu-Khalaf

220 Impostors Everywhere, Richard M. Felder

213 Positions Available
> 213 Books Received
P 248 Meet the Authors
> 249 Book Review

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 ofaddress should be sent to CEE, Chemical Engineering Department,
University of Florida, Gainesville, FL 32611-6005. Copyright 1997 by the Chemical Engineering Division, American
Society for Engineering Education. The statements and opinions expressed in this periodical are those of the writers qnd
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 and for back copy costs and
availability. POSTMASTER: Send address changes to CEE, Chemical Engineering Department., University of Florida,
Gainesville, FL 32611-6005. Periodicals Postage Paid at Gainesville, Florida.

Fall 1997

Award Lecture...




Phillip C. Wankat is Professor
of Chemical Engineering at Purdue
University in West Lafayette, In-
diana, where he has been since
1970. He received his BSChE from
Purdue and his MA and PhD de-
grees in Chemical Engineering
from Princeton University. In 1982
he also received an MS in Educa-
tion from Purdue. He was Head of Freshman Engineer-
ing at Purdue from 1987 to 1995 and its Interim Director
of Continuing Engineering Education in 1996.
Professor Wankat is interested in research in separa-
tions with an emphasis on adsorption, chromatography,
and distillation. He is the Editor-in-Chief for Separation
and Purification Methods and is the author of Large Scale
Adsorption and Chromatography (CRC Press, 1986),
Equilibrium-Staged Separations (Prentice-Hall, 1987),
and Rate-Controlled Separations (Chapman-Hall, 1990).
He has published over 100 technical papers and ten tech-
nical book chapters. He received the ACS Award in Sepa-
ration Science and Technology in 1994 and is a Fellow of
AIChE and ASEE. He is the Co-Editor (with Dr. Kent
Knaebel) of a new section on "Mass Transfer" in the 7th
edition of Perry's Chemical Engineers Handbook.
Professor Wankat is interested in teaching improve-
ment and is the co-author (with Dr. Frank Oreovicz) of
Teaching Engineering (McGraw-Hill, 1993). He and
Frank have co-taught a course for PhD students, "Educa-
tional Methods in Engineering" at Purdue since 1983. He
has published over thirty articles on engineering educa-
tion and is the Associate Editor of the journal Chemical
Engineering Education. He frequently presents teaching
improvement seminars and workshops. He has won sev-
eral teaching and counseling awards at Purdue in addi-
tion to the Dow Outstanding Young Faculty Award, the
Western Electric Award, the George Westinghouse Award,
and the Chester F. Carlson Award, all from ASEE, and
the Chemical Manufacturer's Catalyst Award.

Copyright ChE Division ofASEE 1997

Purdue University West Lafayette, IN 47907-1283

I wish to thank the Chemical Engineering Divi-
sion of ASEE for this award and the Union
Carbide Corporation for its sponsorship of the
award. It is a distinct honor to be included
among the list of distinguished chemical engi-
neers who have received the division's lecture-
ship award.

here is considerable debate about the roles of teach-
ing and research in the University. Astin's'1l exten-
sive survey data shows that on a university-wide
basis teaching suffers when major increases in research oc-
cur. This appears to be a resource allocation issue. For indi-
vidual faculty members, the correlation between research
and teaching effectiveness appears to be zero or very weakly
positive.11'2] In any case, these research results rarely get the
same public attention as do the muckraking attacks by
Sykes,131 Smith,141 and others. The voices supporting a bal-
ance of teaching and research as the ideal5'61 tend to be more
moderate and are drowned out. I feel we should continually
search for a balance between teaching and research. This
paper explores the synergisms between teaching and re-
search that have made my own teaching and research
richer and more effective.
In the ideal university, research and teaching are synergis-
tic; the total output is not additive in the sense of 2 + 2 = 4,
but is greater than the sum of the parts, 2 + 2 = 5, or even 6,
7, or 8. This can come about because of efficiencies in
working on both teaching and research-the same effort
ends up having multiple uses. And teaching and research
provide deeper meaning, each for the other, in unexpected
ways. Of course, there are also times when they have little in
common, but this does not negate the experience of unity
that results when teaching and research synergistically
complement each other.
Chemical Engineering Education

Unlike Gaul, this paper is divided into six parts: since
lecturing is used to communicate for both teaching and re-
search, it starts with lecturing; the second part is concerned
with people; the next part discusses interactions in learning
for both teaching and research; part 4 explores an example of
interaction in a graduate-level course; examples of interac-
tions between research and teaching in undergraduate courses
appear in part 5; and part 6 asks the question, "Is synergy
with service and administrative duties possible?"


The most common method of teaching or reporting re-
search results in engineering is lecturing. Any efforts a pro-
fessor makes to improve lecturing skills will improve both
teaching and research lectures. Three things prevent a lec-
ture from being considered terrible: 71
Not reading to the audience
Speaking loudly enough
Finishing on time
Now, this is easy enough to accomplish and may help ex-
plain why only 11% of engineering students rate their in-
structors as average or below average.[81
An analysis of learning in college~l" showed that student
involvement is needed to obtain learning. This is true in all
lectures. Thus, the lecturer must keep the audience engaged
and generally paying attention. The positive things that can
be done to improve a lecture include the following perfor-
mance attributes: [2,8
Having a positive attitude
Showing enthusiasm
Using visuals
Making eye contact
Remembering the attention span is 15 to 20 minutes
The last point is particularly difficult in a research lecture
since normally a speaker goes nonstop until the question
period. But the norm is wrong. All lectures can benefit from
Breaks with purposeful audience activity
The purposeful activity helps to involve the audience.
Audience analysis is also useful. Audiences hope that the
speaker will
Keep them awake
Be somewhat interesting and even funny
Say something useful to them
If the audience consists of students, they will also want to
Will this material be on the test?
Since the research lecture does not have this last motivation,
Fall 1997

it is even more important to be enthusiastic and humorous.
Note that content plays only a minor role in making a
lecture interesting. Practically any content can be made in-
teresting-or boring.


Chemical engineering is a great profession because the
people involved in it have developed effective ways of solv-
ing important problems. But we often forget the importance
of people. It is somewhat traditional in an award lecture to
thank people who helped along the way. Without becoming
excessively personal, I will briefly discuss some of the people
who have influenced me.
My father was an analytical chemist who worked at UOP
for forty years. One of his favorite sayings was, "What is
your plan B?" I got used to looking for alternatives before
things did not work-not bad training for a professor or a
department head. Throughout high school I planned to be a
chemist, but my father's advice, "Be a chemical engineer,
they're treated better," was convincing. My mother's main
contributions were a drive to get things done, which bal-
anced looking for alternatives, and persistence (or stubborn-
ness, depending on one's viewpoint) in the face of obstacles.
Professor Lowell Koppel taught the mass transfer and
separations course when I was an undergraduate. He sparked
my interest in distillation and separation and was the best
straight (no gimmicks) lecturer I had in my education. Later,
when he was my department head, he taught me that one
should always challenge the premises first.
Professor Bill Schowalter was my thesis advisor at
Princeton, where I did research on hydrodynamic stability
analysis. This was an excellent education for research in
separations since I learned how to pose problems. The great-
est lesson I learned from Bill was to find out why something
puzzling or unexpected occurred. One example of this in-
volved solving the quadratic equation ax2 + bx + c = 0 in the
middle of a loop in a computer program. The sign of the
desired solution would change while the program was run-
ning. Why? (The answer can be found at the end of this
article after "Closure.") This lesson to always find out why
has proven to be important in both teaching and research.
Professor Jud King's book, Separation Processes,1[9 ap-
peared late in 1970, just as I started to do research and
teaching in separations. What a godsend it was! I learned a
great deal about separations from it and used it for ten years
in an elective course at Purdue. When I spent my first sab-
batical at Berkeley, Jud was very supportive of my research
efforts in separations at a time when I badly needed support.
On the pedagogy side, two Purdue professor of education
had a significant impact on my career. Professor John

Feldhusen's course, "Educational Psychology for College
Teachers," made me realize that I did not have to copy what
I had seen in the classroom. Years later, Frank Oreovicz and
I adapted John's course to engineering and developed a new
course, "Educational Methods in Engineering." Much of
John's course survives in the book Teaching Engineer-
ing.[2] Professor Dick Hackney let me take a course in
counseling theories despite my obvious lack of prepara-
tion. He also encouraged my application to earn an MS in
education, and this eventually led to my becoming Head
of Freshman Engineering.
Many other people have influenced my teaching and re-

search. They include colleagues, un-
dergraduate students, and graduate stu-
dents. Hopefully, I have had an equally
positive influence on most of them.
On a personal level, in December
of 1980 an amazing thing happened.
I got married, calmed down, became
happier, and found I was much more
productive. Then we had children,
and I also became responsible. So I
want to thank my wife, Dot, and my
children, Charles and Jennifer, for en-
riching my life.


There is no better fortune for a pro-
fessor than to teach and do research
in the same area. When I am learning
new things about separations, it is
not clear if I am doing this for re-
search or for teaching, or for both.
They build on each other. Research
and teaching are a unified whole with
respect to a professor's learning.
Reading Jud King's book was my
introduction to the countercurrent dis-
tribution (CCD) theory of chroma-
tography. This led to including the
theory in an elective course on sepa-

librium, the fraction of the solute in the mobile phase, f, is
f= 'V where K'(T)=Cm/Cs (1)
Then, (1-f) must be the fraction of solute in the stationary
phase. The discrete transfer step combines the stationary
phase from stage i with the mobile phase from the previous
stage, i-1. The mass balance is

Mi,s =fi-1,s-lMi-,s-_ +(1-fi,,1)Mi,s_1 (2)

where Mi,s is the mass of solute in stage i after transfer step s.
This model results in an equation that is essentially a finite

Figure 1. Comparison of theoretical and ex-
perimental results for discrete transfer test
tube parametric pumping system. Diethyl
ether stationary phase, water moving phase,
acetic acid solute. Theoretical results corre-
spond to: fh=0.515; fc=0.476; Vc=VH=O; 5
stages, 2 transfers per half-cycle.
(Reprinted with permission from Wankat,1ol0 Copy-
right 1973, American Chemical Society.)

rations. Then I used the theory and did countercurrent distri-
bution experiments for parametric pumping"10 and later for
affinity chromatography.1"i The CCD theory has the advan-
tages of being very simple to understand and to program on a
computer. The CCD model was used extensively to model
chromatography before powerful computers became inex-
pensive. In CCD all of the mobile phase in a stage is trans-
ferred simultaneously to the next stage. Then the mobile and
stationary phases in each stage are equilibrated. After equili-
bration, the mobile phase is again transferred. For linear equi-

difference form of the more compli-
cated equations needed to describe
chromatography with continuous flow.
For isothermal chromatography with
a pulse input, f ,s is a constant and an
analytical solution of Eqs. (1) and (2)
is easily developed.' '
In parametric pumping the tempera-
ture and flow direction are changed
periodically. A numerical solution of
Eqs. (1) and (2) is easily generated.1'"0
The results are shown in Figure 1 for
extraction parametric pumping. Al-
though the agreement was obviously
not good (probably because of evapo-
ration of the diethyl ether), the model
was useful since it did not predict the
infinite separation factors that linear
models for columns did. The same
paperti" included a continuous-flow
model for parametric pumping. The
development of that model occupied
over two pages in the journal, com-
pared to less than half a page for the
discrete-transfer model. A number of
other researchers subsequently used
both discrete transfer and continuous-
flow models to model parametric
pumping and other cyclic separations.
This success with a chromatographic
theory led me to take a chromatogra-

phy course from Professor Buck Rogers in chemistry. Buck
encouraged me to become more involved in chromatogra-
phy research. I used the CCD theory to explain affinity
chromatography.I"I The affinity chromatography research
made it abundantly clear that biochemistry was needed, so I
took two biochemistry courses, which helped further re-
search in biochemical separations.[12' About this time I be-
came cocky and thought I knew enough adsorption and
chromatography to develop a graduate-level elective on ad-
sorption and chromatography. Since the teacher invariably
Chemical Engineering Education


learns more than the students, I had to really learn the
different theories of adsorption and chromatography. I spent
a great amount of time studying Chapter 10 of Sherwood,
Pigford, and Wilkel131 and reading the literature.
The students in this graduate separations elective voted to
learn about membranes. Building on what is included in
King's book, membranes were included in the course. This
knowledge eventually became useful in research"141 and later
became two chapters in the textbook."15 This pattern of
building on learning done for teaching to do research and
then building on the knowledge gained in research to im-
prove teaching repeats over and over again.
The knowledge of adsorption and chromatography solu-
tions and mass transfer that I had learned while preparing to
teach unexpectedly proved very useful in developing inten-
sification procedures for adsorption,1161 elution chromatogra-
phy, 171 and PSA.116,18' The first stages of this research were
done during my second sabbatical, spent at ENSIC in Nancy,
France. I decided to take the time to answer a question that
had nagged me for several years. In analytical liquid chro-
matography, the use of smaller and smaller packing had
revolutionized the method and resulted in HPLC. Yet this
development had no impact on adsorption operations and
very little impact on large-scale chromatography, both of
which have very similar mass transfer characteristics to ana-
lytical liquid chromatography. The typical answer to why small
particles were not used was that pressure drop would be too
large, but I was not convinced. Since I was on sabbatical, I
could afford to "waste" my time to look at this question.
In one afternoon a "back-of-the-envelope" calculation con-
vinced me that the common wisdom, based on a constrained
optimization, was wrong. For example, Sherwood, Pigford,
and Wilke show diminishing returns as the particle diameter
decreases. But in their example, the cycle time was set
constant at ten minutes. A reworking of this example"161
clearly shows that there is an advantage to reducing particle
diameter if the cycle time and column length are scaled
The initial analysis was rather approximate and the next
ones were a bit on the messy side. Eventually, simpler ways
of solving the problem, such as the dimensionless analysis
employed to analyze pressure swing adsorption (PSA),'181
were developed. This work actually used what I had learned
about dimensionless analysis in my PhD thesis on hydrody-
namic stability analysis, and thus it illustrates that problem-
solving techniques are often transferable to very different
problems. By the time this material was included in a text-
book,151 the theory had been simplified significantly. The
following development is based on the textbook presenta-
tion, but can easily be extended for more complex cases. The
textbook presentation takes us full circle since the results of
the research are now being taught to students.
Assume that we have an adsorption column that works
Fall 1997

satisfactorily. It does not matter how this "old" design was
developed. We now wish to develop a "new" design. By
taking ratios of the controlling equations, we can do the new
design without solving any differential equations. The pres-
sure drop in a packed bed of rigid particles with laminar flow is

AP= J (3)

where K is the bed permeability that depends only on the
porosity. Taking the ratio of Eq. (3) for the old and new
designs, we obtain

1- APold Void Lold dpnew (4)
R, Apnew Vnew )ew e ) dp,old

The bed porosity for rigid spheres is independent of bed
diameter, bed length, and particle diameter; therefore, to a
first approximation K cancels out in the derivation of Eq.
(4). The interstitial velocity v is related to the volumetric
flow rate Q by
v= (5)
ntD 2E
The ratio of old and new velocities is easily obtained and
substituted into Eq. (4) to obtain

1 Qold Dnew Lold Idp,new (6)
Q-7-w X )7 t) (6)
Rp Qnew Dold Lnew dp,old )
If Rp = 1.0, then the pressure drops in the old and new
designs are equal even though the designs may look very
To consider the separation that is achieved, we define

1 (L/LMTZ)old (7)
R, (L/LMTz)new
where LM, is the length of the mass transfer zone. If RN =
1.0, the fractional bed use in the two designs is identical and
the separation is identical. (For linear chromatography, RN is
defined as the ratio of the number of plates in the new and
old designs.[17]) Substituting the expression for LMrz for a
Langmuir isotherm into Eq. (7), we obtain

1 Qnew Dold ( old kmapold(8)
RN Qold ) DnewJ Lnew ) kmap,new

This simplifies if pore diffusion controls to

7w ()(2
1 Qnew Dold Lold Idpne w (9)
RN Qold Dnew L newJ dp,old

When pore diffusion controls, Eqs. (6) and (9) relate the six
variables Rp, RN, (QnewQold), (Dnew/Dold), (Lne,/Lold), and (dp.,ne
dpod). Four of these are selected as known and the other two
are solved for. Since all of the "old" parameters are known

from the old design, the new parameters are easily determined from the a,
ratios. V, ot
If the only significance of this were scale up, the procedure would not
have had much impact. The significance on economics is easily seen
from a numerical example. If we set Rp = 1, RN = 1, (QeJwQoid) = 1, and
(dp,.,/dp,od) = 0.1, we find that solution of Eqs. (6) and (9) gives (Le, -- Splitter
Lold) = 0.01 and (Dnew/Dold) = 1. To keep the same boundary conditions 'XF
(or the same relative amount of time processing feed), we must cycle
more quickly. For the case considered here, the cycle and feed times
must be scaled as
Stage N
tcycle,new tfeednew _Lnew/Lold (10) F2, XF
tcycle,old tfeed,old L, xout

which is a ratio of cycle times of 0.01. Thus, a very short column
cycling rapidly can produce exactly the same separation with the same b .0-
pressure drop for the same volumetric flow rate of feed if we reduce the v o.0os
particle diameter. Since the adsorbent volume is tD2L/4, this is a much 0.900
smaller column. If the ratio (dp,new/dp,oid) is a significant change, the new
system will need to be redesigned to reduce dead volume.""1 Different
geometries such as annular flow may become viable.[91 Now that I am
finished with this research, it has caught the attention of companies that .40
separate gases by adsorption.
x = 0.194
0. 0.200 0.400 0.600 0.800 1,000
One would expect that graduate students would do a significant C
amount of research for their theses, and, of course, doing this research ooo
involves learning how to do research. By working with the students, the
professor helps the students learn-which is not a bad definition of 0.800 "'
teaching. Thus, teaching and research are synergistic during normal y= .691
graduate student research. Synergism can also occur between research
and graduate students' projects in courses.
Several graduate-student projects in courses have eventually resulted N. I
in papers. For example, Narsi Sundaram, a student in my advanced/ 0 s.
separations course, decided he wanted to look at PSA for his course
project. After a bit of searching, he decided to look at the effect of 0 200
pressure drop on the repressurization and blowdown steps in PSA. I 0 / 0.309
"knew" that this effect would be negligible, but since a negative result o. o ,li oo
0. 0 400 0.600 0900 0. 0
is perfectly acceptable for a project, I gave him the go-ahead. He found

Figure 2. (a) Two-enthalpy feed analog of ordinary flash distilla- -- N=
tion-column-flash distillation. (b) Column-flash distillation: N=5 ,o. N-2
equilibrium stages, q=0.5, ao=5, x,=0.5, constant molal overflow. 1* -- N=5
(c) Column-flash and ordinary flash distillation: McCabe-Thiele anal- a -,- N.o1
ysis, N=1 equilibrium stage, q=0.5, a=5, x,=0.5. (d) Effect of 0.3- -e- N=20
q=F1/(F,+F2) and N on separation of ethanol from water using a /
column-flash system. Results of Aspen Plus simulations. Equilibrium
data used physical property package SYSOP18. Feed is 10 mol % 2- -
water. Pressure=l atm. From left to right in each series of seven
points for a given N: LV=F,/F2=0.25. 0.50, 0.75, 1.00, 2.00, 3.00, 4.00. o0
0.005 0.015 0.025 0.035 0.045
(Reprinted with permission from Wankat and Kessler2, Copyright 1993, 0.005Mole Fraction EOH n Boos
American Chemical Society.)
206 Chemical Engineering Education




0 200 0 0 o 000 uo o0 o o00
Figure 3. (a) Ordinary complete distillation column
with two-phase feed (solid feed line); complete distilla-
tion column with two-enthalpy feed (dashed lines). (b)
McCabe-Thiele diagram for near-minimum-reflux
case-ordinary column with two-phase feed: requires
20 stages to yield x2o=0.050. (c) McCabe-Thiele dia-
gram for same reflux ratio-column with two-enthalpy
feed: requires only six stages to yield x,=0.034.
(Reprinted with permission from Wankat and Kessler,"241 Copy-
right 1993, American Chemical Society.)
Fall 1997

that under certain conditions the effect of pressure drop was
much larger than anyone expected. Narsi switched his thesis
topic to work with me on this in more detail, and eventually
we published the result.1201 This paper led to an outpouring of
other papers on the topic (unfortunately, not by me), and at
least one of the major gas companies changed their computer
modeling to include this effect. So, what do I know?
If space allowed, there are other examples we could explore
in depth. In all cases, additional work was necessary to take
the original student project and make it publishable. This
type of synergism between teaching and research is rela-
tively obvious.


To this point, the synergisms between research and teaching
have involved graduate-level courses or senior electives. There
are synergisms between teaching required undergraduate
courses and research, but they are fewer.
I first became interested in distillation as a junior at Purdue.
I found the McCabe-Thiele diagram to be fascinating. I wanted
to do research on distillation, but for many years couldn't
seem to find an opening. Instead, I taught the junior-level
equilibrium staged course at Purdue for many years and even-
tually wrote a textbook for the course.121J Finally, during a
1992 sabbatical at the University of Florida, I started some
distillation research. (Funny how these things seem to happen
on sabbatical.) I had developed a new PSA process that used
the feed gas for a partial purge.[221 During the hunt for other
possible uses of this idea, I remembered that Suzuki23' had
shown that PSA and distillation were analogous. (Actually,
Suzuki wrote that PSA can be approximately analyzed as a
continuous countercurrent process.) With this (inaccurate) anal-
ogy, the column flash distillation system shown in Figure
2a[241 was developed. At first glance, it does not look like
distillation since there is no reboiler and no condenser. But
years of teaching that distillation is a vapor-liquid separation
system with heat as the separation agent had convinced me
that neither a reboiler nor a condenser is needed. Figure 2a is a
form of distillation. The operating line and the McCabe-Thiele
diagram are shown in Figure 2b. If there is a single stage, the
result becomes the same as normal flash distillation (Figures
2c). The results of more detailed simulations done with Aspen
are shown in Figure 2d. They show that column flash can
achieve more separation than a normal flash.
This was interesting, but not necessarily useful. So Dave
Kessler and I extended the idea to distillation columns. The
eventual result was the two-feed column shown in Figure
3a.1241 A comparison of the McCabe-Thiele diagrams for the
single-feed operation (Figure 3b) to the two feed-system (Fig-
ure 3c) shows that when the single-feed system would be a

two-phase feed, the two-feed column is significantly better.
What is meant by "better" is illustrated in Figures 4a, 4b, and
4c, which are results of Aspen simulations.
After the research was done and while Dave and I were
writing the paper, I realized I had seen this type of two-feed
distillation before. It is homework problem 6D15 in my
distillation textbook.[21] Perhaps there was a subconscious
memory that guided the research. While the paper was in the
galley-proof state, Dave Manley at the University of Mis-
souri-Rolla informed me that several variants of column
flash distillation are covered by U.S. patent 4,726,826 (1988).
My next step will be to incorporate these results in the
junior distillation course in the fall of '97. The column flash
system will make an excellent test or homework problem.
There are also enriching and stripping column examples in
the paperl241 that will make novel problems for the students.
My experience using Aspen for research will be helpful in
using Aspen in the course.
What if you teach courses that are not in your research
area? Are there still possible synergisms between teaching
and research? What if you teach mass and energy balances? I
admit that finding ties between a mass and energy balance
course and research may be difficult. After a twenty-two
year hiatus, I had the opportunity to teach the mass and
energy balance course in the spring of 1997. I used the little
red bible[251 as the text. The material was essentially the same
as it had been twenty-two years ago, but the students had
changed. Going back and reviewing the fundamentals with a
different textbook did bring an increased depth to my under-
standing-I saw an analogy between the choice of reference
states for energy balances with a heat of mixing and energy
balances for adsorbers with a heat of adsorption. This under-
standing was helpful in current adsorption modeling research.
Another type of synergy occurred in teaching the mass and
energy balance course. This was a synergy between teaching
different areas. After about a fourth of the semester, I knew
the course was not going well-many students were not
learning. Leaning heavily on what I had written[21 and taught
about how to teach, I asked the students to write down what
they thought would help them learn on a 3x5 card. Using
these comments as a guide, I reorganized the remainder of
the course. The course improved and the end-of-semester
student evaluations were quite positive.


I considered adding "service" to the title of this paper, but
I did not want to lose my credibility at the outset. Although it
often seems like a black hole for effort, service and adminis-
trative positions can occasionally interact synergistically with
research and teaching. Probably the main synergism is the
people both inside and outside the university who one meets


--- two-phase, xF = 0.5
--- two-leed, xF= 0.5
-- two-phase, xF = 0.8
-U- Iwo-leed, xF = 0.8

relative theoretical
volatllty stages
2 36
4 18
6 15
8 13 ~


14% -- xF 0.5
SxF =0.8
12%--------- -e- xF-0.8
< 8%--
Srelative theoretical

I 8 I 13 I

2 3 4 5 6 7 8

3-5- xF = 0.5
30% ----- -- xF=0.8
25%--- __
S20% relative theoretical
n0 volatlllt tages
15% 2 36
4 18
10% 15
r 13


Figure 4. (a) Effect on reflux ratio of using two-enthalpy
feed rather than two-phase feedfor x,=0.99, x,=O.01, q=0.5.
(b) Effect on cooling requirements of using two-enthalpy
feed rather than two-phase feed forxD=0.99, x,=O.01, q=0.5.
(c) Effect on heating requirements of using two-enthalpy
feed rather than two-phase feed forxD=0.99, xB=O.01, q=0.5.
(Reprinted with permission from Wankat and Kessler,"24 Copy-
right 1993, American Chemical Society.)

while serving on committees or as an administrator. There
are often mutual research or teaching interests that can
blossom into collaborations or even funding. This is par-
ticularly true of professional service in organizations such
as to ASEE or AIChE.
A second benefit, particularly of administrative positions,
is the acquisition of a much broader outlook. My experience
as Head of Freshman Engineering was extremely useful
when I was writing Teaching Engineering.12] Contact with
students and professors helped me see the similarities and
Chemical Engineering Education



differences in teaching engineering in the different engineer-
ing disciplines. This helped make Teaching Engineering a
book for all engineering professors, not just for chemical
engineering professors.
These examples within the university may seem farfetched.
Serving as a journal editor, on the other hand, is normally
directly related to one's own research. An editor who reads
manuscripts in order to make editorial decisions is forced to
keep up with the literature in his or her broad area of re-
search. Without this extra incentive, I would read only
the literature in my narrow area of specialization. My
duties as an associate editor of Chemical Engineering
Education have forced me to read and sometimes under-
stand advances in chemical engineering outside of what I
usually teach or research.

Although teaching and research are often viewed as oppo-
sites, they often interact synergistically. Efforts to improve
as a lecturer will at the same time improve both teaching
lectures and research presentations. Learning because one
needs to know something for classroom teaching or for
research can be both effective and efficient. Once learned,
the knowledge is then available for unexpected uses in re-
search or teaching. Learning appears to be the major syner-
gistic mechanism between teaching and research. Syner-
gisms do occur between course teaching and research. The
most obvious of these are when course projects blossom into
research projects. Research results are often, quite deliber-
ately, translated into a form that can be taught to graduate or
undergraduate students.

ANSWER TO QUESTION: The sign on a term multiplying
the equation was switching from plus to minus or vice
versa. If both sides of the quadratic equation are multi-
plied by -1, the sign used for the solution switches.

a surface area/volume of adsorbent, m2/m3
c concentration in mobile phase, kg/m3
C, concentration in stationary phase, kg/m3
d particle diameter, m
D column diameter, m
f fraction of solute in mobile phase, Eq. (1)
i index for stage
km lumped parameter mass transfer coefficient, m/s
K permeability in Eq. (3)
K' equilibrium constant, Eq. (1)
L column length, m
LMz length of mass transfer zone in column, m
M mass of solute in stage, kg
p pressure, N/m2
Q volumetric flow rate, m3/s
RN ratio of L/L in new and old design, Eq. (7)
R ratio of d in new and old designs, Eq. (4)
s index for transfer step
Fall 1997

t time, s
T temperature, "C
v interstitial velocity in column, m/s
V volume of mobile phase in stage, m3
V volume of stationary phase in stage, m3
e external porosity
Ut viscosity, poise

1. Astin, A.W., What Matters in College? Four Critical Years
Revisited, Jossey-Bass, San Francisco, CA (1993)
2. Wankat, P.C., and F.S. Oreovicz, Teaching Engineering,
McGraw-Hill, New York, NY (1993)
3. Sykes, C.J., Prof Scam: Professors and the Demise of Higher
Education, Regnery Gateway, Washington, DC (1988)
4. Smith, P., Killing the Spirit: Higher Education in America,
Viking, New York, NY (1990)
5. Rosovsky, H., The University: An Owner's Manual, W.W.
Norton, New York, NY (1990)
6. Pelikan, J., The Idea of the University: A Reexamination,
Yale University Press, New Haven, CT (1992)
7. Reid, L.D., "How to Improve Classroom Lectures," Amer.
Assoc. Univ. Prof. Bulletin, 34(30, 576 (1948)
8. Centra, J.A., Reflective Faculty Evaluation, Jossey-Bass,
San Francisco, CA (1993)
9. King, C.J., Separation Processes, McGraw-Hill, New York,
NY (1971)
10. Wankat, P.C., "Liquid-Liquid Extraction Parametric Pump-
ing," Ind. Eng. Chem. Funds., 12, 372 (1973)
11. Wankat, P.C., "Theory of Affinity Chromatography," Anal.
Chem., 46, 1400 (1974)
12. Busbice, M.E., and P.C. Wankat, "pH Cycling Zone Separa-
tion of Stgars," J. Chromatography, 114, 369 (1975)
13. Sherwood, T.K., R.L. Pigford, and C.R. Wilke, Mass Trans-
fer, McGraw-Hill, New York, NY (1975)
14. Hong, J., G.T. Tsao, and P.C. Wankat, "Membrane Reactor
for Enzyme Hydrolysis of Cellobiose," Biotech. Bioeng., 23,
1501 (1981)
15. Wankat, P.C., Rate-Controlled Separations, Chapman-Hall,
London, England (1990)
16. Wankat, P.C., Large Scale Adsorption and Chromatogra-
phy, Vol. I, CRC Press, Boca Raton, FL (1986)
17. Wankat, P.D., and Y.M. Koo, "Scaling Rules for Isocratic
Elution Chromatography," AIChE J., 34, 1006 (1988)
18. Rota, R., and P.C. Wankat, "Intensification of Pressure Swing
Adsorption Processes," AIChE J., 36, 1299 (1990)
19. Rota, R., and P.C. Wankat, "Radial Flow Pressure Swing
Adsorption," in F. Meunier and M.D. LeVan (eds.), Recents
Progres en Genie Des Procedes, Vol. 5, No. 17, Adsorption
Processes for Gas Separation, CNRS-NSF GIF 91, Lavoisier
Technique et Documentation, Paris, France, 143 (1991)
20. Sundaram, N., and P.C. Wankat, "Pressure Drop Effects in
the Pressurization and Blowdown Steps of Pressure Swing
Adsorption," Chem. Eng. Sci., 43, 123 (1988)
21. Wankat, P.C., Equilibrium-Staged Separtions, Prentice-Hall,
Englewood Cliffs, NJ (1988)
22. Wankat, P.C., "Feed Purge Cycles in Pressure Swing Ad-
sorption," Separ. Sci. Technol., 28, 2567 (1993)
23. Suzuki, M., "Continuous-Countercurrent-Flow Approxima-
tion for Dynamic Steady State Profile of Pressure Swing
Adsorption," AIChE Symp. Series, 81, (242), 67 (1985)
24. Wankat, P.C., and D.P. Kessler, "Two-Feed Distillation:
Same Composition Feeds with Different Enthalpies," Ind.
Chem. Res., 32, 3061 (1993)
25. Felder, R.M., and R.W. Rousseau, Elementary Principles of
Chemical Processes, 2nd ed., Wiley, New York, NY (1986) 0




University of Ottawa Ottawa, Ontario, Canada K1N 6N5

n this article we will present a method for improving the
traditional approach to selecting potential graduate stu-
dents. The goal of the method is to apply more equitable
strategies and reduce the chances of rejecting the "right"
students. The method, known as the "structured interview,"
is currently used by industrial/organization psychologists to
select employees for many major corporations.['21] Although
some may question the notion that student selection is an
educational issue, we feel strongly that a commitment to the
fairest possible selection method models and teaches integ-
rity to students.
New faculty members are often advised by their peers,
mentors, and former supervisors to carefully select graduate
students who are best suited to the member's specific field
and setting. In fact, it is often said that the choice of graduate
students in the early stages of a career heavily influences
one's long-term success as well as that of the students in
question. In some settings, selection is done at the depart-
mental level. In such cases, the method described here can
be easily adjusted to meet departmental selection needs.
A number of professors were interviewed regarding the
secret of their success in recruiting successful graduate stu-
dents. Recommendations included using criteria such as good
marks, high ambition, and good interpersonal skills-and
even good luck was cited. Although the responses served to
describe successful graduate students, they did not offer a
systematic approach to differentiating between applicants.
This is an especially difficult task considering the limited
amount of time generally devoted to screening applications
for graduate studies. Unfortunately, many professors con-
fess that the selection of quality graduate students is basi-
cally a "crap shoot."
One of the most widely used tools for selecting graduate
students is the interview. It serves two purposes: to select
graduate students and to sell the professor's (or the

department's) research program to the student. A traditional
interview usually consists of an interviewer engaging in a
"free-wheeling" conversation with the student. This is known
by experts in the field of industrial/organizational psychol-
ogy as an "unstructured" interview.131 The professor asks
many different kinds of questions, some of which may be
conjured up on the spot. It appears, however, that most
interviewers tend to rely on a set of questions commonly
used by their colleagues.
This traditional approach to conducting an interview often
results in hiring the best interviewee rather than the best
candidate. In fact, recent research findings indicate that this
approach has only a 15 to 20% chance of predicting perfor-
mance.141 This is particularly unfortunate because it is diffi-
cult and costly within the structure of most graduate pro-
grams to have unsuccessful students withdraw. Table 1 com-
pares research findings concerning the ability of various
selection tools to predict job performance.

Marc A. Dubd received his BSc in chemical en-
gineering from Queen's University, and his MASc
and PhD from the University of Waterloo. He
recently joined the University of Ottawa faculty.
His research interests are polymer reaction engi-
neering (experimental kinetics and mathematical
modeling of bulk, solution, and emulsion poly-
merization of multicomponent systems) and ap-
plied statistics.

Mama Zinatell received her BSc, MASc, and
PhD in psychology at the University of Water-
loo. She began her career at the University of
Waterloo Counseling Services, where she also
provided psychological services within the Fac-
ulty of Engineering. She is currently a psy-
chologist at the University of Ottawa Career
and Counseling Services and in the Faculty of
Engineering. She also operates a private prac-
tice where she provides therapy and consult-
ing services.

Copyright ChE Division ofASEE 1997

Chemical Engineering Education


The interview procedure discussed here can be somewhat lengthy, but when one expects to work with the
candidate for a period that can span two to six or more years, it makes sense to spend a reasonable
amount of time on the selection process. ..... it appears worthwhile to invest energy in developing
strategies for selection that incorporate the latest available expertise.

Because most questioners tend to ask the
candidate to evaluate themselves (e.g., Ti
"What are your weaknesses?"), a skillful Validity of
interviewee can turn an interview into a Recritm
pleasant, yet uninformative, session. The
result is that an interviewee who is well- Unstructured I
versed in interviews may well be consid- Reference Che
ered for a position over a poor interviewee Assessment Ce
who has the potential to become an excel- Unstrucured E
lent graduate researcher. Psychological
Traditional unstructured interviews also Structured Inte
suffer from the fact that they contain no
systematic rating procedure. Typically, the
interviewer makes a decision based on a TA
"gut feeling" or a "hunch." In fact, inter- Qualiti
viewers tend to make a decision about an Successful (
applicant within the first four or five min-
utes of the interview.131 In other words, the Aca
first impression made by a prospective can- Wi
didate turns out to be extremely important. De
This is troubling since the first few minutes List
of an interview are typically devoted to idle
banter that serves to put the candidate at
ease. Research has also identified the fol- Oral Con
lowing characteristics of unstructured inter- Oi
views:[3] inm
Interview ratings are more influenced Cre
by unfavorable information than byfa-
vorable information. Interl
Interviewers recall information pre-
sented at the beginning and at the end
of an interview better than informa-
tion in the middle.
Interview ratings are better if the ap-
plicant follows a poor candidate and worse if the
applicant follows a good candidate.
Interviewers see female applicants as more appro-
priate for certain positions (regardless of qualifica-
Interviewers give better ratings to applicants with
whom they have more in common.

One solution to the above problems is the "structured"

ent o


~ Po




interview. The use of a structured inter-
LE view forces the interviewer to avoid stray-
etion Tools for ing from a predetermined question sheet
ifPersonnel'41 and avoids the use of non job-related
questions (such as marital status, age,
...............0.20 child care, or religion) that can result in
...................... .26 litigation.t" In fact, precedents have al-
................ 0.36 ready been set in which structured inter-
Interview .....37 views have protected interviewers from
g.......... ...0.53 litigation.[3] What many fail to realize is
......... ......0.70 that interviews are viewed by the courts
as tests, and as such they are subject to
the same validation requirements.[21

pE 2 A structured interview is characterized
assessed by by four basic features: a series of ques-
uate Students tions relevant to the job, immediate scor-
ing of the answers to the questions, scor-
:Skills ing based on benchmark answers, and
Skills the calculation of a sum for an overall
ability interview score.131 Comparisons can be
SSkills made to a benchmark overall interview
tion score or between competing candidates.
on l The development of the structured in-
cation Skills terview is straightforward and has been
action outlined by Wiesner.31] First, one must
dence identify examples of effective, ineffec-
Ability tive, and typical behaviors that contrib-
eace ute to the success or failure of graduate
ud Skills students. It is generally advisable to draw
-e m upon the experience and expertise of sev-
-y Skills eral qualified individuals to accomplish
rSkills this task in order to justify the choice of

In our case, extensive consultation
with peers and senior colleagues was undertaken first. After
establishing a list of qualities (see Table 2), a set of questions
was generated to assess the degree to which each candidate
possessed the qualities. The questions were designed to re-
flect typical work situations and to reveal the presence or
absence of the quality in question. Benchmark answers and
scores were then generated for each question, and the prede-
termined answers and scores were used to evaluate candi-
date responses. At the conclusion of the interview, the scores
were tabulated. They can be compared either to competing
candidates or to a previously established "cut-off' score.

Fall 1997

Certain qualities, such as laboratory and computer skills,
can be rather difficult to assess by means of a question-and-
answer session. In these cases, a simple situational assess-
ment[2] is performed, e.g., the candidate is asked to actu-
ally perform the skill being evaluated as part of the inter-
view process.

Using recommendations from the literature,"1
4] we have designed a structured interview for
selecting candidates for graduate school in
chemical engineering. The interview is based
on the qualities associated with success in
graduate school (as outlined in Table 2). Be-
cause widely distributed information concern-
ing the specific questions and situational as-
sessments used would obviously threaten the
validity of the interview and undermine the
goal of this work, they are not included in
the present paper, but professors interested
in obtaining a copy of the question sheet can
contact the authors (e-mail address:

A typical interview is presented here with
omission of certain specific details in order to
protect the validity and reliability of the in-
Prior to the interview, an academic transcript
is obtained from the candidate; it is scored based
solely on third- and fourth-year marks since
these are, in our opinion, generally more repre-
sentative of current performance in chemical
engineering than first- and second-year marks.
An academic quality score is obtained in the
following manner: 1 for an average below 75%;

2 for an average from 75 to 79%; 3 for an average from 80 to
84%; 4 for an average from 85 to 89%; and 5 for an average
of 90% or greater (the scale chosen here could also be
based on grade-point averages or letter grades). We sug-
gest incorporating the use of reference letters only if they
are submitted by reliable sources. It is, however, always
advisable to check references.
The candidate's writing skills can also be assessed via
their letter requesting the interview. If the candidate comes
from within the interviewing department, ask him/her to
submit a formal written request for the interview. This letter
can then be graded for grammar, structure, spelling, etc., and
scored out of 5. (We consider it a plus if the student has
enough foresight to have the letter proofread by someone.)
At the beginning, the interviewer should put the student at
ease by doing most of the talking. This is an opportune time
to tell the candidate about your own expectations and about

your research. When the "sales pitch" is completed, it is time
to begin the structured interview. The student should be
informed that he/she is now going to be evaluated in a
consistent and equitable manner by being asked the same
questions as any other candidate. (In our experience, this
explanation satisfies students who are very accepting of
structured interviewing, most likely because
they understand the importance of using a
widely fair and empirically validated method of se-
uted election ) You may choose to allow the stu-
ation dent to take notes.
ng the The interview proceeds with the posing of
questions and presentation of scenarios to
which the candidate must respond. For in-
itional stance, in order to assess oral communica-
its used tion skills, the candidate can be asked to tell
viously the interviewer about his/her hobbies and in-
terests. During this time, the interviewer
n the should concentrate on the oral communica-
of the tion skills of the candidate rather than giv-
w and ing careful attention to the content of what
the goal is being said. The candidate can be given
1 point for each of the following criteria:
t eye contact, audibility, command of the
luded in language, grammar, and a logical progres-
t paper, sion of ideas.
essors The creative ability of the candidate can
ed in be evaluated by posing a technical problem
that you are currently trying to solve. The
copy of candidate can be given 1 point for each rea-
mn sheet sonable idea, up to a maximum of 5.
act the The candidate's interpersonal skills can
s. .. be assessed by proposing a scenario in which
a conflict with a co-worker arises. Scores
can be allotted based on how the candidate

proposes to resolve the conflict.
Some skills cannot be assessed simply by an applicant's
verbal response to a simulated scenario. This is the case for
the candidate's laboratory skills and computer skills.
For example the candidate could be invited to perform
simple laboratory-skills tests and then be observed for
errors such as improper measurements, inefficient use of
equipment, poor calculations, inability to follow instruc-
tions, haste, cleanliness, etc.
Clearly, no single characteristic can be perfectly assessed
using a single structured interview question. But together,
the questions comprising the structured interview serve
to give a more valid indication of the candidate's future
The total score should be calculated immediately after the
student leaves. If so desired, the questions can be weighted
differently, depending on their relative importance as per-

Chemical Engineering Education

specific qi
and situa
would ob
of this woi
are not inc
the present
but profit
obtaining c
the question
can conte

ceived by the interviewer.
A professor can refine a structured interview to more
accurately reflect the required skill set. Skills or qualities can
be added and extra questions or hands-on tests can be incor-
porated into the interview as needed. Conversely, certain
skills or qualities can be eliminated. In other words, the
interview is based on a situational assessment of the specific
requirements for the job. Not all supervisors (or depart-
ments) are created equal. Some may want a very indepen-
dent, ambitious, and creative student, while others may want
what amounts to a technically skilled, obedient, and depend-
able laboratory technician.
One challenging situation involves the implementation of
a structured interview in the case of international students. A
long-distance phone interview, or video conferencing, or
similar technologies may provide a partial solution. It may
also be possible to have an on-site trusted colleague perform
all or part of the interview.
The interview procedure discussed here can be somewhat
lengthy, but when one expects to work with the candidate for
a period that can span two to six or more years, it makes
sense to spend a reasonable amount of time on the selection
process. This is particularly important given the time and
effort required to supervise graduate students and the signifi-
cant contributions that talented students can make. Thus, it
appears worthwhile to invest energy in developing strate-
gies for selection that incorporate the latest available
expertise. This structured interview is currently being
implemented and data are being collected regarding its
success in predicting performance.
As mentors, it is important to model fairness and integrity.
Use of a structured interview can convey these values and
demonstrate to students that their evaluation is based on
competencies and not on irrelevant personal traits.

Many thanks to Professor Willi Wiesner of McMaster
University and Dr. David Lynn for their helpful discussions.
Many colleagues were involved in the initial discussions
regarding the qualities possessed by top graduate students,
and for this they are gratefully acknowledged.

1. Daniel, C., and S. Valencia, "Structured Interviewing Sim-
plified," Public Personnel Management, 20(2), 127 (1991)
2. Pursell, E.D., M.A. Campion, and S.R. Gaylord, "Structured
Interviewing: Avoiding Selection Problems," Personnel J.,
907, Nov. (1980)
3. Wiesner, W.H., "Chapter 9: Interviewing," in Recruitment
and Selection in Canada, V.M. Catano, S.F. Cronshaw, W.H.
Wiesner, R.D. Hackett, and L.L. Methot, eds., ITP Nelson,
Toronto, Ontario (1997)
4. Van Clieaf, M.A., "In Search of Competence: Structured
Behavior Interviews," Business Horizons, March-April, 51
(1991) 0

Use CEE's reasonable rates to advertise.
Minimum rate, 1/8 page, $100;
Each additional column inch or portion thereof, $40.

Faculty Position in Chemical Engineering
The Department of Chemical Engineering invites applications for a
tenure track faculty position at the Assistant Professor level. A Ph.D. is
required and applicants must have at least one degree in Chemical
Engineering, an outstanding record of research accomplishments, and
a strong interest in undergraduate and graduate teaching. Preference
will be given to applicants with skills that will add to the Department's
strengths in bioengineering, environmental science and engineering,
interfacial phenomena and fluid mechanics, materials processing and
science, process analysis, and separation processes. The successful
candidates are expected to teach undergraduate and graduate courses,
develop a research program, collaborate with other faculty, and be
involved in service to the university and the profession. Applications
from women and minorities are encouraged. Interested persons should
submit a detailed curriculum vitae including academic and profes-
sional experience, a list of peer reviewed publications and other techni-
cal papers, and the names, addresses, and telephone numbers of three
or more references to: Chairman, Department of Chemical Engineer-
ing, The University of Texas at Austin, Austin, Texas 78712-1062. The
University of Texas is an Equal Opportunity/Affirmative Action Em-

S= books received

Surface Properties, edited by I. Prigogine and Stuart A.
Rice; John Wiley & Sons, 605 Third Avenue, New York NY
10158; 432 pages, $95.00 (1996)
Immobilization of Enzymes and Cells, edited by Gordon F.
Bickerstaff; Humana Press, 999 Riverview Drive, Suite 208,
Totowa, NJ 07512; 367 pages, $79.50 (1997)
Advances in Chemical Physics, by I. Prigogine and Stuart A.
Rice; John Wiley & Sons, 605 Third Avenue, New York NY
10158; 330 pages, $125 (1996)
Patent Strategyfor Researchers and Research Managers, by
J. Jackson Knight; John Wiley & Sons, 605 Third Avenue,
New York NY 10158; 166 pages, $49.95 (1996)
The Surface Science of Metal Oxides, by V.E. Henrich and
P.A. Cox; Cambridge University Press, 40 West 20th Street,
New York, NY 10011-4211; 464 pages, $99.95 (hardback)
$39.95 (paperback) (1996)
Numerical Methods for Engineers, by Santosh K. Gupta;
Franklin Book Co. Inc., 7804 Montgomery Ave., Elkins
Park, PA 19117; 407 pages (1995)
New Methods in Computational Quantum Mechanics, edited
by I. Prigogine and Stuart A. Rice; John Wiley & Sons, 605
Third Avenue, New York NY 10158; 813 pages, $130

Fall 1997

r learning



Part 2. Elementary Levels

Clemson University Clemson, SC 29634-0909

This is the second of three papers* that stalk the question
of what we mean by an understanding of technical mate-
rial. In the first paper of the series, we noted that to
understand has multiple meanings; our goal in these pa-
pers is to clarify the distinctions among those meanings
and to organize them into a useful hierarchy. We also
summarized what is now known about the structure and
function of the human brain, and we used that knowledge
to draw certain implications about the nature of learning.

ny study involves many kinds of understandings
and many ways to reach any of them. We propose
that the ways of understanding technical material
can be organized in a hierarchical fashion so that a progres-
sion through the hierarchy carries the student, in a system-
atic way, to a broader and deeper appreciation, perception,
and comprehension of the material. The hierarchy consists
of seven levels, shown in Figure 1.
In formal educational settings, much of a student's effort
seems to be devoted to solidifying understanding at the
current level, while much of the instructor's effort seems to
be devoted to preparing students for the transition to the next
level. Since the transitions carry the student to higher levels
of understanding, the transitions between levels must be as
important as the levels themselves.
A successful transition involves at least the two following
characteristics. First, each transition must be motivated. In
the early stages (levels 1 to 5), the transitions are motivated
when we realize that mastery at the current level is not
sufficient for our immediate needs. In the later stages (levels
5 to 7), the transitions are motivated when we realize that
mastery at the current level enables us to move beyond our
immediate needs. Second, each transition involves a refor-
mulation of understanding at the current level. That is, un-

* Part 1, "Brain Structure and Function," was published in the
summer 1997 issue of CEE (Vol. 31, No 3) and Part 3, "Advanced
Levels," will be published in the Winter 1998 issue of CEE.

derstanding at the new level subsumes, but does not replace,
understanding at previous levels. In each of the following
sections, we first discuss a level and then provide the
motivation and reformulation that constitute the transi-
tion to the next level.

Study begins when our attention is drawn to the objects,
processes, and concepts that constitute a topic. At this most
superficial level, understanding is just sufficient to enable
students to participate in conversations about the topic. They
at least know the names of some of the subject's primitive
objects and concepts, so they can pose questions. With more
exposure, they may even be able to converse fluently about
the material. Yet at Level 1, they still lack any skill in using
the objects and concepts.
For conversation to succeed as communication, partici-
pants must properly use the names of objects and concepts.
It is a seductive misconception, however, to believe that the
correct use of a name implies a correct understanding of the
named object. For primitive humans, a name was thought to
be an intrinsic part of an object, and that calling the name of
an object exerted control over it. Thus, one of Adam's first
acts in the Garden of Eden was to name the animals. Joseph
Campbell has noted that in some ancient Indian cultures,
pronouncing the Sanskrit name of a god was thought to call
forth the god.1" A similar tradition operated in ancient Juda-
ism, so that correct pronunciation of the name of God (YHVH)
was first held secret, then later avoided. In fact, in Judaism
and other ancient cultures, names were considered to be so
powerful that the entire universe was thought to have been
created, not out of nothing, but from a calling of names.[2]
This ancient penchant for names was not intended to sig-

J.M. Haile is professor of chemical engineering at Clemson University, and
is the author of Molecular Simulation, published by John Wiley & Sons in
Copyright ChE Division ofASEE 1997
Chemical Engineering Education

nal understanding, but rather to com-
pensate for lack of understanding. In
modern times, we may still use names
to deal productively with things we
don't understand (an example is grav-
ity). That is, sometimes we find it
useful to substitute a name in place of
the object named, even when the ob-
ject itself is not understood.
In the classroom, however, manipu-
lating names in place of objects can
obscure rather than enlighten. Con-
sider Feynman's example of tribolu-
minescence, which can be described
as the emission of a photon that may
occur when certain crystals are sub-
jected to sudden high pressure.'3 Such
a statement may be precise, but it re-
ally only trades one name for other
names (photon, crystal, emission, pres-
sure); to attach meaning to such a state-
ment, a student must explicitly con-
nect these names to physical objects.
Left to their own devices, many stu-
dents fail to make such connections.
They can be helped by translating for-
mal descriptions into more familiar


(1) Making Conversation

(2) Identifying Elements

(3) Recognizing Patterns

(4) Solving Problems

(5) Posing Problems

(6) Making Connections

(7) Creating Extensions


Vague ideas reduced
to clear concepts

Concepts organized
into patterns

Patterns assigned
meaning within a
problem context

Procedures for
solving problems
learned by repetition

Concept, pattern, and
context generalized to
other domains

Solution procedure
modified for other
problem contexts

Figure 1. The levels of understanding
and the transitions between them.

terms, such as this: when a few grains of sugar are taken into
a dark room and squeezed with a pair of pliers, we might see
a small flash of light-that's triboluminescence.141 Names
can help draw our attention to things,t'5 but knowing names
is only a first step toward understanding.
Level 1 (Making Conversation)
Level 2 (Identifying Elements)
Motivation: Verbal fluency with a portion of a domain is
not the same as having clear ideas about the objects compris-
ing the domain, or knowing which objects are most impor-
tant, or knowing how the objects can be used.
Reformulation: Vague and ambiguous ideas are reduced
to concise and accurate statements about the structure and
function of objects and concepts.

When we identify the elements-the objects and con-
cepts-that constitute a topic, we define the elements and try
to give a sense of how the element behaves in typical situa-
tions. Let's consider definitions first: a complete definition
should encompass both structure and function. A structural
definition should include two things: the identify of the class
to which the object belongs and a list of those characteristics
that distinguish it from other members of its class. A func-
Fall 1997

tion are important, here are five diagnostic questions that stu-
dents and instructors can use to test understanding of elements:
1) What is it?
2) How is it related to or how does it differ from other
members of its class?
3) For what is it used?
4) How can it fail?
5) How can we learn about it?
These diagnostics are illustrated in Table 1 for a concrete
thing and for an abstraction. In addition to objects, these
diagnostics can also be applied to processes; you might care
to practice by applying them to flash distillation.
Note that questions (1) and (2) are ontological in that they
address structure; questions (3) and (4) are causative in that
they address function; and question (5) is epistemic.[61 For
concrete things, a typical response to question (5) is to take
the thing apart or to operate it. For mathematical abstrac-
tions, a typical response is to explore the object's behavior
by doing calculations with simple models. Note also that
question (5) is intended to move the student from pure defi-
nitions toward meaning. That is, definitions do not necessar-
ily constitute meaning, because meanings generally involve
cross connections among objects, concepts, and levels of
understanding. Consider,
When an ideal gas is heated in a closed rigid vessel, its
internal energy always increases.

tional definition should also include
two things: the typical or common
use of the object, together with iden-
tification of situations where the ob-
ject is not useful or in which it fails.
The words used in these definitions
must be words already known to the
students; we are trying to build foun-
dations in students' minds by reorga-
nizing and expanding what they al-
ready know, and we can only build
from the materials available.
Structural and functional definitions
should be provided for concrete
things, abstract things, and processes.
We tend to define concrete things in
terms of function (a valve is a pipe
fitting used to control flow) and to
define abstractions in terms of struc-
ture (entropy is the thermodynamic
state function obtained by applying
an integrating factor to the inexact dif-
ferential formed by the reversible heat).
To the extent that this observation is
true, it is one source of students' dis-
comfort with abstractions. To help us
remember that both structure and func-

The unfortunate-such as a politician or a royal person-
age-might well know the definition of each word in this
sentence without grasping the meaning of the sentence. To
move toward meaning, students must participate in some of
the activities suggested by the answers to question (5).
Level 2 (Identifying Elements)
Level 3 (Recognizing Patterns)
Motivation: Knowing the identities and uses of individual
objects is not the same as knowing how the objects are related
or how they can be combined to increase their effectiveness.
Reformulation: Individual objects and concepts are orga-
nized into meaningful patterns.

Structural and functional definitions can be given to most
objects, concepts, and processes, but such definitions carry
little meaning until the defined things are related to other
objects, concepts, and processes. We use the word pattern to
refer to those relations that impart meaning to sets of objects,
concepts, and processes. For example, structural and func-
tional descriptions of fugacity are given in Table 1; but
meanings for fugacity can only be extracted from its relation
to processes (such as diffusion) and to other properties (such
as temperature and composition). Thus, a fugacity gradient
measures a driving force for diffusion: a substance diffuses
from a region of high fugacity to one of low fugacity. More-
over, when a fugacity is balanced across an interface, we

(1) What is it? Valve whose body houses a chair-shaped seat located
roughly mid-way between body walls. At the lower end
of the stem is a disk that fits into a seat when the stem
is lowered.

(2) How is it related to or how
does it differ from other
members of its class?

(3) For what is it used?

(4) How'can it fail?

(5) How can we learn about it?

Differs from other valves in structure of seat and disk.
Distinguished from others by globular shape of body.

For fine control of flow, as opposed to gate and ball
valves, which only provide on/off control.

Worn seat and disk; leaks in packing; jammed stem;
stripped threads on stem; solid matter blocking seat.

Study design drawings; study cut-away model; take one
apart; operate one in situ; operate one in a process

have an absence of diffusional driving forces, producing
diffusional equilibrium. Thus, the fugacity fits into a general
pattern that uses driving forces to explain changes.
Other meanings can be attached to the fugacity by consid-
ering other relations. In fact, a general observation is that
one object may participate in several different patterns and,
moreover, that more than one pattern can often be contrived
from the same set of objects and concepts. This is illustrated
schematically in Figure 2. From the same objects, different
patterns provide flexibility in that one pattern may prove
more useful in one situation while another serves better in
another situation. This flexibility leads to a problem-solving
strategy; when a particular pattern of known information
does not seem to be leading to a solution, try reformulat-
ing the information into a different pattern. When we say
a concept is rich in meaning, we imply that it contributes
to multiple patterns.
One of the great mathematical physicists of the 19th cen-
tury, Henri Poincar6, had an understanding of classical dy-
namics that anticipated modern studies of nonlinear dynam-
ics, unstable systems, and chaos. He was also deeply curious
about the nature of creativity and the workings of the mind.
In addressing the question as to why most people cannot
understand mathematics, Poincar6 wrote[7]

A mathematical demonstration is not a simple juxtaposi-
tion of syllogisms, it is syllogisms placed in a certain order,
and the order in which these elements are placed is much
more important than the elements themselves.

Such ordering of elements produces patterns, so we can

In a mixture containing component i at mole fraction x, the fugacity f is
the thermodynamic state function obtained from the following isothermal
derivative of the chemical potential:
di = RTdfnfi
with low-pressure boundary condition lim f .
P-O0 fi =xiP
Differs from chemical potential pi and activity a in that absolute values
can be obtained for fugacity f, but only relative values can be obtained for
gi and a,.

To express criteria for phase and reaction equilibria; thus fugacity provides
starting points for solving phase and reaction equilibrium problems.

Not useful unless a model (such as a PVTx equation of state) is
is available that relates f to measurables, such as T, P, and x.

Explore its T, P, and x, dependence by performing calculations using simple

16 Chemical Engineering Education


interpret this statement by saying that
people fail to understand meanings to
the extent that they fail to recognize and
interpret patterns.
The pattern is the fundamental unit of
understanding not just in mathematics,
science, and engineering, but in any in-
tellectual activity. For example, in mu-
sic a single note or chord has essentially
no meaning; musical meaning arises only
when notes are organized into patterns.
In the piano music of Bach, for example,
many patterns can be identified as math-
ematical transformations of some rela-
tively simple theme. Experienced musi-
cians do not study music at the level of
notes but at the level of phrases-pat-
terns of notes. Similarly, masters at chess
study their game not in the positions of
individual pieces, but in the patterns pro-
duced by the relations among the posi-
tions.8] It is intimate familiarity with
patterns that allows a master to play,
and win, several games simultaneously.

- .-
* -

* 0

~ S
0 I

Figure 2. Let each
an isolated fact or
tion; any one suc
meaning. But by es
facts, we create pc
motion takes on m,
*I--1_^____ __1_____

Patterns are distinct from classifica- nmusrarea scnema
That each of these
tions. Classifying objects according to tha ea o e
the one arrangemi
common characteristics helps us orga- left. That is, the s
nize information, and it may help us ally be organized
identify relations and patterns, but a clas- terns, none neces,
sification does not establish relations but some more use
among objects. Note also that a mean- lar situations.
ingful pattern does not necessarily re-
sult when we simply organize information into a familiar
structure. In the use of language, this observation motivates
the distinction between syntax (proper structure) and seman-
tics (meaning).[6] For example, consider this German sen-
tence from Wiener:[9]
Der Geist will es, aber der Fleisch ist schwach.
A syntactically correct, word-for-word translation would be
"The ghost want to, but the meat is rare." Although this
translation preserves the syntax of the original, it fails to
capture the meaning. In a syntactically correct structure,
meaning is rarely embedded in individual elements; rather, it
is usually gleaned from relations among the elements. A
meaningful pattern is more than the sum of its parts.
Confusion as to the distinction between syntax and seman-
tics seems pervasive and a cause for concern. We now have
software that can check the spelling and grammar used in
student themes, lab reports, and term papers; we have equa-
tion solvers by which students can readily implement all
kinds of numerical methods; we have symbolic manipula-
tors that students can use to take derivatives, evaluate inte-

Fall 1997

* *

Sdot on the left represent
a single piece of informa-
h fact has essentially no
tablishing relations among
itterns in which the infor-
eaning. Three patterns are
tically on the right. Note
Patterns is formed from
ent of dots shown on the
ame information can usu-
into several distinct pat-
sarily "right" or "wrong,"
ful than others in particu-

grals, and perform algebra; we have
process simulators that students can
use, not only to perform complex de-
sign calculations, but also to replace
experience in laboratories. Over a pe-
riod of just a few years, we have intro-
duced an astonishing number of black
boxes into our courses, with little con-
cern about their impact on understand-
ing gained or lost by students. The
point here is that a syntactically cor-
rect manipulation of a black box does
not necessarily evoke any semantically
correct response from the student who
operates the box.
In the hands of an expert, a black
box can offer positive benefits-it can
enable more work to be done in less
time. Experts attach meaningful rela-
tions between input and output, and
they are sensitive to any deviation from
an expected outcome. If an outcome is
unexpected, they have other indepen-
dent means for checking. But a posi-
tively beneficial tool in the hands of an
expert can be positively dangerous in
the hands of a novice. Novices cannot
make logical and meaningful relations
that connect output to input, they have
ill-formed expectations as to what the
output should be, they are not aware of
how a black box can be wrong, and
they have few if any independent

mechanisms for checking the output.
Given our present understanding of how minds work, it is
difficult to see how a black box, which is intended to hide
the relations between output and input (i.e., hide patterns),
can be used to establish meaningful relations in the brains of
students. It may be, however, that some use of black boxes
can reinforce or strengthen patterns that have been estab-
lished through other learning activities. Thus, a black box
should be introduced only after students have developed
understanding about those relations hidden by the box.
Since the cerebral cortex lears by modifying existing
structures, presenting new patterns should always proceed
inductively, starting from particulars. For example, say the
goal is to develop the pattern we call the stuff equation:

( Rateof ( Rateof ) ( Rateof ) ( Rateof ) ( Rateof
STUFFinto STUFFout |I+ generation consumption accumulation
systemby ofsystemby ofSTUFF of STUFF ofSTUFF
interactionsJ minteractionsJ insystem J insystem insystem

We should start with a particular application, preferably
extracted from the student's experience-balancing a check

book is a possibility, wherein the "sys-
tem" is the bank account and "stuff" is
money. Additional, very different, appli-
cations are usually needed to help stu-
dents solidify interpretations of all terms.
Only then should we present the gener-
alization, using "stuff," in the above form.
Patterns are effective devices because
minds seek patterns. Since minds try to
find patterns in any case, we might as
well try to develop patterns that are
known to be effective and useful. In-
versely, we should help students avoid
patterns that are misleading or unproduc-
tive. That is, we should devote some effort
to showing students ways not to think.
Patterns are also effective because they
provide a means for attaining efficiency
in education. With the quantity of tech-
nical information doubling every five

Observable World



Figure 3. Schematic of
section of information
world onto a pattern.
many-to-one; that is, the
but suppress others. T1
such projections takes
when it is superimposed

years, how can we ever teach it all? The answer is not merely
that we can't, but more importantly, that we shouldn't. Re-
peatedly presenting new applications without establishing
any overriding pattern wastes resources because it provides
no lasting benefit to students. The purpose of a university
education is not to simply teach facts or to train operators of
black boxes; rather, it is to develop a small core of important
patterns in the brains of students. Important patterns are
those that will help students grow by adding new informa-
tion to their existing core. Likewise, new information is
important to the extent that it connects to old information
and established patterns; without such connections, new in-
formation is isolated and essentially meaningless. By exten-
sion, we should not teach any topic that lacks patterns that
could serve as a basis for future growth of students.
Level 3 (Recognizing patterns)
Level 4 (Solving Problems)
Motivation: Recognizing a pattern is not the same as know-
ing how the pattern can be used or recognizing situations in
which it can be used.
Reformulation: The pattern is connected to problem
situations-contexts in which the pattern takes on par-
ticular meanings.

At previous levels, our attention is focused on identifying,
defining, and attaching meaning to objects, concepts, and
patterns. Now we begin to use those objects, concepts, and
patterns to answer questions; the formulation of answers is
called problem solving. To solve problems, not only must

we be aware that certain patterns ex-
Problem Context
ist, but we must also recognize when
they are useful. That is, patterns them-
selves are useless until they are re-
lated to still other patterns, objects,
=f 0 and concepts. These other related
-- 0 things constitute a context in which a
O pattern acquires a particular meaning.
O 'The act of recognition amounts to a
.) projection of relevant information onto
an appropriate pattern in the problem
context. In the language of group
a homomorphic pro- theory, such a projection is homomor-
from the observable phic in that only relevant information
Such projections are is projected; irrelevancies are sup-
ey preserve some facts pressed. This is illustrated schemati-
he pattern created by
e pattern cread by cally in Figure 3. These projections
a particular meaning
d onto a problem con- are usually homomorphic because
reality nearly always provides more
information than we need. Recog-
nition of the appropriate projection
is a vital step in solving a problem.
To illustrate a homomorphic projection, say we are faced
with a heat exchanger that is no longer operating to specifi-
cations. One diagnostic would be to check the energy bal-
ance. Thus, we determine the temperatures, pressures, com-
positions, flow rates, and phases of all streams and project
them onto the pattern of the stuff equation; under this projec-
tion the stuff equation becomes an energy balance. This
projection is homomorphic in that we need only information
about streams into and out of the exchanger; information
about the interior of the exchanger, such as heat transfer
areas and heat transfer coefficients, is suppressed. The result
of the energy-balance calculation may or may not help us
solve the problem; if it does not, then we seek other pat-
terns. The lessons here are that the problem context suggests
patterns that may be useful and the context imparts meaning
to the results obtained from the patterns. Thus, say we find
that the energy balance is satisfied with 3%; is this satisfac-
tory or not? The answer depends on context. In some situa-
tions 3% would be perfectly satisfactory, but in others it
would be absolutely devastating. Students often have diffi-
culty reconciling the meaning of a computed number to the
context of the calculation.
The projection from the observable world onto a pattern in
the problem context is a first step in developing a solution
procedure. The development of a complete procedure is an
important aspect of achieving understanding at Level 4; we
do not address the detailed aspects of that development here,
however, because a considerable body of literature already
exists. The modern literature on solving problems begins
with Polya,l"" and a continuing survey is available from
Woods.1'" We do, however, emphasize three general points
about solving problems.
Chemical Engineering Education

First, we have two general strategies for solving problems:
an offensive strategy, in which we try to move toward a
stated goal, and a defensive one, in which we try to avoid
undesirable penalties. In most situations, we use an offen-
sive strategy, but if we can't find a successful offensive
strategy, then we should consider a defensive one. The les-
son here is to maintain flexibility; in some situations, penalty
avoidance is sufficient to be successful. For example, an
offensive strategy guides most investments in the stock mar-
ket (the goal is to increase capital), but in some markets the
winning strategy is a defensive one (to avoid losing capital).
Second, one mistake that commonly prevents our solving
a problem is a failure to verify default assumptions. Default
assumptions are those many aspects of experience that we
take to be generally true. Such assumptions free us from
having to repeatedly make the same judgment about a fa-
miliar situation. Without default assumptions, we could
rarely find time to accomplish anything new. But some-
times we cannot solve a problem because a default as-
sumption no longer applies. Polya lists several in a math-
ematical context,112] such as
1) If we have N equations in N unknowns, then we can solve
for the unknowns.
Here are some others:
2) If a simple algorithm provides a result, a complex algo-
rithm will provide a more reliable result.
3) If a statement is true, then so too is its converse.
4) If any data fail to fit the expected pattern, we can ignore
those data.
5) If two effects are similar, then their causes are similar.
This assumption takes several forms, including: Large
effects have large causes.
6) If the problem has boundaries, then its solution has the
same boundaries.
Confining the search for a solution to the boundaries of the
problem is a common source of difficulties; in some situa-
tions, simply extending the boundaries converts an intrac-
table problem into a trivial one.
Third, in problem solving, memory plays multiple, con-
flicting roles. On one hand we need long-term memories to
recall patterns that might be helpful in the current problem
context. (These might be evoked from Polya's heuristics:11l0
Have you ever solved this problem before? Have you ever
solved a similar problem?) On the other hand, we need
short-term memories to identify our current position in the
solution procedure, to recall how results from previous steps
affect the current step, and to recall how results at the current
step are to be used in subsequent steps. The simultaneous
use of these memories seems to interfere with creation of
new memories; that is, in any challenging problem, so many
neural networks are activated that few are available for form-
ing new memories. When we solve a new problem for the
first time, our attention is so preoccupied with finding the
Fall 1997

solution that we rarely learn how to solve it. This observa-
tion motivates the transition to Level 5.

In this paper we have suggested that the multiple mean-
ings for technical understanding can be organized into a
hierarchy, and we have described understanding at the el-
ementary levels. In our discussion of those levels, an impor-
tant point has emerged: the fundamental unit of understand-
ing is the pattern. Patterns impart meaning by providing
structures that establish relations among chunks of informa-
tion, so our understanding of a topic remains rudimentary
until we can see patterns. Further, we advance to higher
levels of understanding only to the extent that we can recog-
nize, interpret, and apply patterns. The importance of this
point can probably not be overemphasized. We conjecture
that one of the most effective improvements we can make in
education is to organize material so that students learn pat-
terns, not sequences of individual facts.
As students progress through the first levels of under-
standing, they move from an initial encounter with a topic to
some facility with solving problems. So, when they are able
to solve problems at Level 4, they have made significant
progress. Nevertheless, achieving skill at solving problems
marks a rather elementary level of understanding; solving a
problem is not the same as knowing how to solve it. This
realization begins the transition from Level 4 to Level 5.
This transition is often difficult to make and therefore it is
the one we use to distinguish elementary understanding from
more advanced levels. Those advanced levels will be de-
scribed in the third paper in this series.

1. Campbell, J., Primitive Mythology, Vol. 1 of The Masks of God,
Viking Penguin, New York, NY (1959)
2. Genesis, Ch. 1; Gospel of John, Ch. 1, V. 1
3. Feynman, R.P., Surely You're Joking, Mr. Feynman, Bantam Books,
New York, NY (1986)
4. It is now known that triboluminescence is an artifact caused by
impurities in the crystals.
5. Minsky, M., The Society of Mind, Simon and Schuster, New York,
NY (1986)
6. Searle, J., The Rediscovery of the Mind, MIT Press, Cambridge,
MA (1992)
7. Poincar6, Henri, "Mathematical Creation" in The Creative Process,
B. Ghiselin, Ed., The New American Library, Inc., New York, NY
(1952) First published as "Le Raisonnement Math6matique" in
Science et Mgthode, E. Flammarion, Paris, France (1908)
8. Hirsch, Jr., E.D., Cultural Literacy, Houghton Mifflin, Boston, MA
9. Wiener, N., Invention: The Care and Feeding of Ideas, MIT Press,
Cambridge, MA (1993)
10. Polya, G., How To Solve It, 2nd ed., Princeton University Press,
Princeton, NJ (1957)
11. Woods, D.R., PS News, a newsletter on problem solving, published
bimonthly at the Department of Chemical Engineering, McMaster
University, Hamilton, Ontario, Canada L8S 4L7
12. Polya, G., Mathematics and Plausible Reasoning, Vol. 1, Princeton
University Press, Princeton, NJ (1954) 1

Random Thoughts...


North Carolina State University Raleigh, NC 27695-7905

Once again the fall semester has snuck up on me
while I was looking the other way. Among the things
I was definitely going to do this summer but didn't is
the fall-issue Random Thoughts. I decided to rerun
the first column in the series (Fall, 1988) instead,
confident that most of you are too young to remem-
ber it (and even more confident that you didn't do
what you were going to do this summer either, so
you should have no trouble relating).

He knocks on my office door, scans the room to make

sure no one else is with me, and nervously ap-
proaches my desk. I ignore the symptoms of crisis
and greet him jauntily.
"Hi, Don-what's up?"
"It's the test tomorrow, Dr. Felder. Um ... could you tell
me how many problems are on it?"
"I don't see how it could help you to know, but three."
"Oh. Uh ... will it be open book?"
"Yes-like every other test you've taken from me during
the last three years."
"Oh ... well, are we responsible for the plug flow reactor
energy balance?"
"No, it happened before you were born. Look, Don, we
can go on with this game later, but first how about sitting
down and telling me what's going on. You look petrified."
"To tell you the truth, sir, I just don't get what we've been
doing since the last test and I'm afraid I'm going to fail this
"I see. Don, what's your GPA?"
"About 3.6, I guess, but this term will probably knock it
down to... "

"What's your average on the first two kinetics tests?"
"And you really believe you're going to fail the test tomor-
"Uh ...."
Unfortunately, on some level he really does believe it.
Logically he knows he is one of the top students in the
department and if he gets a 60 on the test the class average
will probably be in the 30's, but he is not operating on logic
right now. What is he doing?
The pop psychology literature calls it the impostor phe-
nomenon. ] The subliminal tape that plays endlessly in Don's
head goes like this:

I don't belong here ... I'm clever and hard-working
enough to have faked them out all these years and
they all think I'm great, but I know better.., and one
of these days they're going to catch on ... they'll ask
the right question and find out that I really don't
understand... and then... and then...

The tape recycles at this point, because the consequences
of them (teachers, classmates, friends, parents, ... ) figuring
out that you are a fraud are too awful to contemplate.
I have no data on how common this phenomenon is among
engineering students, but when I speak about it in classes

Richard M. Felder is Hoechst Celanese Pro-
fessor of Chemical Engineering at North Caro-
lina State University. He received his BChE from
City College of CUNY and his PhD from
Princeton. He has presented courses on chemi-
cal engineering principles, reactor design, pro-
cess optimization, and effective teaching to vari-
ous American and foreign industries and institu-
tions. He is coauthor of the text Elementary
Principles of Chemical Processes (Wiley, 1986).

Copyright ChE Division ofASEE 1997

Chemical Engineering Education

and seminars and get to ". and they all think I'm
great, but I know better...," the audience resonates
like a plucked guitar string-students laugh ner-
vously, nod their heads, turn to check out their neigh-
bors' reactions. My guess is that most of them be-
lieve deep down that those around them may belong
there but they themselves do not.
They are generally wrong. Most of them do be-
long-they will pass the courses and go on to be-
come competent and sometimes outstanding engi-
neers. But the agony they experience before tests
and whenever they are publicly questioned takes a
severe toll along the way. Sometimes the toll is too
high: even though they have the ability and interest
to succeed in engineering, they cannot stand the
pressure and either change majors or drop out of
It seems obvious that someone who has accom-
plished something must have had the ability to do so
(more concisely, you cannot do what you cannot
do). If students have passed courses in chemistry,
physics, calculus, and stoichiometry without cheat-

it to

that if
you are
you arwe
subject to


ing, they clearly had the talent to pass them. So where did
they get the idea that their high achievements so far (and
getting through the freshman engineering curriculum is in-
deed a high achievement) are somehow fraudulent? Asking
this gets us into psychological waters that I have neither the
space nor the credentials to navigate; suffice it to say that if
you are human you are subject to self-doubts, and chemical
engineering students are human.
What can we do for these self-labeled impostors?

Mention the impostor phenomenon in classes and
individual conferences and encourage the students
to talk to one another about it.

There is security in numbers; students will be relieved to
learn that those around them-including that hotshot in the
first row with the straight-A average-have the same self-

Remind students that their abilities-real or other-
wise-have sustained them for years and are not
likely to desert them in the next twenty-four hours.

They won't believe it just because you said so, of course-
those self-doubts took years to build up and will not go away
that easily. But the message may get through if it is given

repeatedly. The reassurance must be gentle and
positive, however; it can be helpful to remind stu-
dents that they have gone through the same ritual
of fear before and will probably do as well now as
they did then, but suggesting that it is idiotic for a
straight-A student to worry about a test will prob-
ably do more harm than good.
Point out to students that while grades may be
important, the grade they get on a particular
test, or even in a particular course, is not that
crucial to their future welfare and happiness.
They will be even less inclined to believe this
one, but you can make a case for it. One bad quiz
grade rarely changes the course grade, and even if
the worst happens, a shift of one letter grade changes
the final overall GPA by about 0.02. No doors are
closed to a student with a 2.84 GPA that would be
open if the GPA were 2.86. (You may not think
too much of this argument, but I have seen it carry
weight with a number of panicky students.)

Make students aware that they can switch ma-

jors without losing face.

It is no secret that many students enter our field for ques-
tionable reasons-high starting salaries, their fathers wanted
them to be engineers, their friends all went into engineering,
and so on. If they can be persuaded that they do not have to
be chemical engineers (again, periodic repetition of the mes-
sage is usually necessary), the consequent lowering of pres-
sure can go a long way toward raising their internal comfort
level, whether they stay in chemical engineering or go some-
where else.
Caution, however. Students in the grip of panic about their
own competence or self-worth should be deterred from mak-
ing serious decisions (whether about switching curricula or
anything else) until they have had a chance to collect them-
selves with the assistance of a trained counselor.
One final word. When I refer at seminars to feeling like an
impostor among one's peers, besides the resonant responses
I get from students I usually pick up some pretty strong
vibrations from the row where the faculty is sitting. That's
another column.

1. Clance, Pauline R., Impostor Phenomenon: Overcoming the
Fear that Haunts Your Success, Peachtree Pubs., (1985) 0

All of the Random Thoughts columns are now available on the World Wide Web at

Fall 1997 221



University of Virginia Charlottesville, VA 22903 USA

In 1589, a young man carrying a number of different
spheres trudged to the top of the Leaning Tower of Pisa
and proceeded to make an impact on history. After cen-
turies of speculation about whether solid bodies of different
sizes and densities would fall at the same or different rates,
Galileo Galilei's famous demonstration showed that mass
and density make no perceptible difference in the rate of fall.
His apparently courageous (or perhaps arrogant?) act of
actually conducting the experiment and the ultimate impact
of his results have been a source of inspiration for genera-
tions of scientists, encouraging them to take the "path less
traveled" in making their own discoveries of significance.
According to Gerald Holton,t' Galileo was like most of
the "scientists" of his era-quite different from today's sci-
entist. He performed most of his experiments privately and
did not write about them (some historians challenge whether
he did any experiments). But, back then as well as now,
science was a search for cosmic truths based on thematic
presuppositions-that is, beliefs and instincts pushed things
forward. Thus, true to the science of his time, Galileo would
have been convinced of his view about equal rates, and if the
experiment had turned out different from what he expected,
he might have been tempted to deal with the crisis in an
unacceptable way, as Sidney Harris illustrates in Figure 1.
It is this story-and the cartoon's "rest of the story"-that
comprise the dual themes of this paper. The notions of what
technical research is and how it is carried out are examined,

John O'Connell is H.D. Forsyth Professor of
Chemical Engineering at the University of Vir-
ginia. He received his BA from Pomona College,
his BS and MS from MIT, and his PhD from the
University of California Berkeley. He taught ther-
modynamics and statistical mechanics as well
as materials science for chemical engineers at
the University of Florida from 1966-88. His re-
search on fluids involves theory, molecular simu-
lation, and experiment.
Copyright ChE Division ofASEE 1997

1997 by Sidney Harris
Figure 1. Reprinted from The Physics Teacher, 1992.

especially in light of today's technology and objectives. But,
even when we know what to do, we have to deal with
various pressures-the pressure to produce, the limitations
on our resources, the calls for elimination of everything that
is not immediately and directly applicable, and the demands
to "fix up" an ailing research establishment. These pressures
may lead us away from the true quest of research and into
unprofessional conduct. My goal here is to help research
advisors and their coworkers to more fully appreciate techni-
cal research and to improve their performance. The refer-
ences listed at the end of this paper are only a few of the
many available, and there is a wealth of material in them,
Chemical Engineering Education

C Spc T RA

The rewards of a life spent in research are both personal and communal, although the latter is often
not fully appreciated. Research findings contribute to the total body of knowledge, giving
the research scientist a valid sense of community and commonality.

especially concrete suggestions. Finally, I will demonstrate
one way to use the case studies in the National Academy's
booklets2' to give graduate students some experience with
research dilemmas and allow them to practice both group
work and oral communication.
First, the assumption is that researchers want to do the best
they can. If they fall short, it is probably not because they
want to get away with the minimum amount of work pos-
sible or, worse, that they just don't care or, worst of all, that
they cheat. Human frailty, limited experience, and value
conflicts are usually the cause of confused behavior.

"A Corollary to Murphy's Law"
Do not ascribe to maliciousness what can be ascribed to
While sometimes bad things are intended, mostly they're not!

Also, although the discussion in my resource materials is
often couched in terms of "science" because many of the
leaders and speakers are scientists, the truths discussed here
also work for engineering and engineering science research.
Applied research has the same ultimate effect as does basic
research: "to make claims about the world that are subject to
empirical tests."

The most relevant definition of research in the 1971 Ox-
ford English Dictionary is:

"Research 3. A search or investigation directed to the
discovery of some fact by careful consideration or study
of a subject; a course of critical or scientific inquiry."
Early usage includes:
"The matter lies deep in Nature and requires much
research ... [to] unfold it."
W. Holder, 1694.
"Our most profound researches are frequently nothing
better than guessing at the causes of the phenomena."
J. Robertson, 1799.

This definition is pretty dry, perhaps circular, and even de-
pressing-as are most definitions. Interestingly, the idea of
research has been around for centuries, yet it is young in
human history. Also, scientific truth is not fixed and univer-
sal. Not only does the "truth" evolve, but even the methods
of scientists to decide about truth change and continue to
Fall 1997

develop." But there seems to be a force that attracts people
of all persuasions, all over the world, to observe and develop
new, more accurate, more complete, and more useful de-
scriptions of the physical, biological, and social world.

What is it that drives people to conduct research? It is,
after all, a process that can consume lives. The geneticist,
Barbara McClintock, observed,[2] "I was just interested in what
I was doing. I could hardly wait to get up in the morning and
get at it. One of my friends, a geneticist, said I was a child,
because only children can't wait to get up in the morning to get
at what they want to do." What a wonderful way to live!
Success at research can engender the joy of triumph. A
book by Sindermanm31 describes both the techniques and the
rewards of a life spent in scientific research. Although such
views can encourage a person to consider such a commit-
ment, real experience is needed to decide if the effort is
personally worthwhile.
The rewards of a life spent in research are both personal
and communal, although the latter is often not fully appreci-
ated. Research findings contribute to the total body of
knowledge, giving the research scientist a valid sense of
community and commonality. The positive aspects most
researchers cite are

1. They like it; it is exciting and fun!
2. Success can yield personal and communal triumph.
3. They associate with people who care about similar con-
4. Challenging assumptions and seeking new things are
5. Confidence comes from relative freedom and responsibility.
6. They belong to a community based on trust and honest
7. The results can make positive impacts on society.

Of course, there is also a down side:
1. Many failures in measurements or hypotheses are found
(Murphy's Original Law, "If anything can go wrong, it
2. Disagreements over results, interpretation, or credit
sometimes arise.
3. Success is sometimes minimized because of different value
structures ("It must have a practical use!").
The most negative view of research that I have found was
expressed by Sir Francis Bacon:[4] what research encounters
in the "subtlety of Nature, the secret recesses of truth, the
obscurity of things, the difficulty of experiment, the implica-
tion of causes, and the infirmity of man's discerning power,

[will make it so that] men are no longer excited, either out of
desire or hope, to penetrate farther."
There really are more downs than there are ups to re-
search, so a young person considering it as a career should
concentrate on the positive aspects and take to heart what
molecular biologist Stanley Prusiner said:l51 "It's OK not to
understand everything"-especially in the beginning.
The issue of who should do research is treated very well in
the books by Medawar[41 and Oliver.[6] They describe some
personal traits that indicate who might have a high probabil-
ity of success. It is important to remember that technical
workers are not all the same. Medawar says, "Scientists are
people of very dissimilar temperaments doing different things
in very different ways. Among scientists are collectors, clas-
sifiers and compulsive tidiers-up; many are detectives by
temperament and many are explorers; some are artists and
others artisans. There are poet-scientists and philosopher-
scientists and even a few mystics." This description includes
researchers of all disciplines, including modelers, who are
often not given full status in the enterprise. Done well, a
successful model advances knowledge and practice by find-
ing the essentials of a behavior, giving an understanding of the
relative importance of contributions to a complex situation,
and creating a reliable basis for implementing the knowledge.


There are many books on how to do research; some are in
the bibliography. The book by Wilsont7 is like a manual of
investigation while that by Oliver[61 is more philosophical
and attitudinal (and delightful to read!). Their Tables of
Contents reveal different thrusts (see Table 1).
The National Academy's publication[t2 gives another ap-
proach that shows the issues associated with the social foun-
dations of research. Research is not the popular stereotype of a
"lonely, isolated search for truth." In particular, today's "scien-
tific research cannot be done without drawing on the work of
others or collaborating with others. It inevitably takes place
within a broad social and historical context, which gives sub-
stance, direction, and ultimately meaning to the work of indi-
vidual scientists .... An individual's knowledge properly enters
the domain of science only after it is presented to others in such
a fashion that they can independently judge its validity."
This "collaboration" occurs through conversation, com-
puter mail, meeting presentations, manuscripts (which are
scrutinized by reviewers before publication), and published
papers. "This process of review and revision is critically
important. It minimizes the influence of individual subjec-
tivity by requiring that research results be accepted by other
scientists. It is a powerful inducement for researchers to be
critical of their own conclusions because they know that
their objective must be to try to convince their ablest col-
leagues." Nobel Prize winner Michael Brown advised,t5'


"Think of every way possible to shoot down your own idea
before you can begin to accept it." It sort of works just isn't
good enough! One should ask, "Would I stake my job or
career on this result?"
"Science has progressed through a uniquely productive
marriage of human creativity and hard-nosed skepticism, of
openness to new contributions and persistent questioning of
those contributions and of the existing consensus."[2] And, as
mentioned before, this process of validation also evolves as
our knowledge and techniques advance.

There are many problems involved in the performance of
research. After all, if it could be done easily for fun and
profit, everyone would plunge right in. Among the many
issues that could be discussed, I will address only a few.
Experiments and Data Treatment

"To learn the secrets of Nature, we must first observe.
Roger Bacon
"Developing theories without data is like making bricks
without clay."
Sherlock Holmes
"But ask... of the earth, ... and [it] shall teach you ....
Job 12:7-8
After realizing the importance of conducting experiments,
we need to use the results in the most effective ways. Some

Books on Research

"An Introduction to Scientific Research"'7'
E.B. Wilson, Jr., 1952
1. Problem Choice and Statement
2. Searching the Literature
3. Elementary Scientific Method
4. Design of Experiments
5. Design of Apparatus
6. Execution of Experiments
7. Classification/Sampling/Measurement
8. Analysis of Experimental Data
9. Errors of Measurement
10. Probability/Randomness/Logic
11. Mathematical Work
12. Numerical Computations
13. Reporting Research Results

"The Incomplete Guide to the Art of Discovery"'6'
J.E. Oliver, 1991
1. About Discovery
2. Strategy for Discovery
3. Tactics for Discovery
4. Personal Traits and Attitudes for Discoverers
5. Caveats
6. A Few Views and Comments on Science
7. The Inside Story of 1 Discovery
8. Closing Remarks

Chemical Engineering Education

things to avoid are:
1. Uncertain values or errors and noise due to unrecognized
limits of technique or equipment.
2. Prevention of independent verification because of incom-
plete description of measurement conditions and/or analy-
3. Distortion of reality by rejection/retention of inappropri-
ate data points.
4. Prejudicial conclusions about the quality of a model from
using incomplete or biased data.

We know that data can be fallible; this means that an
organized and searching skepticism is necessary. The key
question is how to work so that truth is maximized?
Consider three cases involving great scientists:
1) Lord Rayleigh discovered the element argon by noticing
that the density of nitrogen gas prepared by absorption of
oxygen from air differed from that of gas prepared by
chemical formation. Considering the cause of the discrep-
ancy led to the conclusion that there was more than just
oxygen and nitrogen in air (which, in turn, had originated
with the observation that these were the dominant and
reacting components of air).
2) Physicist J. Donald Fermie says81' that in 1613 Galileo
recorded the data needed to discover the planet Neptune.
However, by either oversight or by rejecting his own draw-
ing, it took 234 more years for Neptune to be "found."
3) Fermie also says that Michelson decided in advance that
electrons had to come in integer values on his oil drops. As
a result, he threw out a bunch of data that yielded 1/3
values and thus lost the opportunity to discover quarks at
the same time!
Examining and validating all the data can result in more than
meets the eye.
The treatment of measured data is handled thoroughly and
well in the book by Wilson.[7' I learned of a favorite case of
MIT's pioneering chemical engineering professor Warren K.
Lewis that might also be illustrative-the "Three-Point Di-
lemma" (see Figure 2). At first glance, it seems impossible
to make sense of these data. But a correlation could be valid
with information from a rigorous theory (such as the value at
x = 0) and experimental uncertainties (see Figure 3). While
the data may seem very rough, that's not the point: informed
analysis gives maximum knowledge.
Recent advances in computers allow computation, imag-
ing, and synthesis of phenomena in incredible ways. Using it
as a tool in our research repertoire, the computer pushes us
amazingly far into quantitative descriptions of Nature, al-
lows examination of multitudes of models, and creates im-
ages at all scales of distance and time that are unavailable
experimentally. Simulation has become the most ubiquitous
and hottest methodology ever known.



> 2


0 1 X 2 3 4

Figure 2. The Three-Point Dilemma:
How to Draw the Correlation?

Validating simulation requires the same care as experi-
ment. In addition to the need for awareness about sensitivity,
undetected assumptions, and insufficient sampling, there must
also be detection of computer-code errors and adherence to
reporting only believable significant figures. Multiple checks
of limits and consistency are required.
I have heard more than once from Stanford Chemistry
Professor Hans Christian Andersen, "Simulation is very se-
ductive. But, like most things seductive, it is not necessarily
wholesome." We probably have at least our share of fools
and scoundrels in simulation since such care may not always
be taken."
Linus Pauling has quoted'9' the physicist John Van Vleck
as saying, "I have never made a contribution ... that I didn't

0 1 X 2

3 4

Figure 3. The Three-Point Dilemma
How to Draw the Correlation!

Fall 1997


get by fiddling with the equations." Pauling then added his
own aside, "I've never made a contribution that I didn't get
by just having a new idea. Then I would fiddle with the
equations to help support the idea." (Here, "fiddling" does
not mean faking or fantasizing-it means assessing the im-
portant and unimportant contributions and doing exploratory
calculations. In that way, inadequacies in sign, trend, form
and magnitude, including omissions, can be found, and one
can connect proposed adjustments to physical and chemical
insights.) Note that in both styles there was equation fid-
dling. Such fiddling was probably the dominant mode of
quantitative exploration before extensive computations were
possible. In this modern age of ever-increasing computer
power and ease, we must remember that people should do
the thinking and machines should do the work.
Judgments, suppositions, and beliefs
If Galileo had really encountered the spheres falling as
depicted in the cartoon at the beginning of this article, he
could respond as pictured only if there were evidence to the
contrary and he knew why the Pisa experiment was flawed.
But that would not be "altering the data." Now we are
better at developing our ideas while maintaining aware-
ness of hazards in the process (see Table 2).

In addition to mastering the various techniques for gather-
ing information, researchers must also recognize many ethi-
cal aspects. The US scientific enterprise has recently been
questioned and threatened because of human issues. To-
day, the cartoon reaction could result in disbarment.
We must examine how the values of science are under-
stood and practiced, especially in "conflicts of values" situa-
tions. This is the central focus of an article in Science1[5 and
is a major portion of the booklet On Being a Scientist.[21
Research programs in chemical engineering do not usually
encounter such issues directly, but we abdicate our responsi-
bilities as technical professionals and informed citizens if we
do not consider what is involved in the ethical issues of
technical research. Note that this introduces the one thing
that research is supposed to avoid-irrationalities. They ap-
pear because research is a human process.
Margaret Somerville, director of McGill University's Cen-
ter for Medicine, Ethics, and Law, put it succinctly,[51
"Good ethics depends on good science. If you're not
doing good science, you're not even in the ballpark of
doing good ethics."
Classifying the issues
We need to be aware of what we get into with research.
One's sense of values must be established and prioritized at
the very beginning. Only a prepared mind and spirit can
stand up to the pressures that students encounter (be produc-

Issues in Judgment and Self-Knowledge

1. In selecting the best hypothesis to proceed with, look for:
A. Internal consistency
B. Accurate correlation and prediction of measurements
C. Unification of apparently disparate observations
2. Using personal intuition-the good and the bad
A. Will one's instincts and experience always lead to
B. Is one always motivated by desire for truth, beauty, and
C. What is really assumed in one's work? Is it a help or

tive, get good grades, initiate a lifelong career) and those that
faculty encounter (keep funding, attract coworkers, balance
education, research, and service activities) and still maintain
academic freedom and values. While there are many ways
to phrase and rank these values, I like what eminent
physicist Alvin Weinberg said:121 "A sense of responsi-
bility is [the trait] I would put at the top. A scientist can
be brilliant, imaginative, clever with his hands, profound,
broad, narrow-but he is not much as a scientist unless
he is responsible."
The booklet On Being a Scientistt21 lists some troublesome
aspects arising from value conflicts in technical research:

Personal Interest: financial involvement, confidential
knowledge, etc.
Publications and Openness: false claims of discovery,
commercial proprietary secrets, multiple publication
of the same work, many short papers
Allocation of Credit: lack of proper recognition,
citations, number of authors, and accountability
Errors and Negligence: lax standards and quality,
sloppiness, and lack of trustability
Misconduct and Deception: fabricating data, falsifying
results, plagiarism, cover-ups, reprisals against
whistleblowers, malicious allegations, violation of
due process in handling complaints.

Action in cases of unethical conduct
First, we must not be tolerant of-much less support-
substandard conduct, especially when it comes to unethical
behavior. If we know a wrong has been done, we are obli-
gated to act. Inaction can cause problems ranging from mere
obstruction to real damage to one's own research, particu-
larly to the credibility necessary to have one's results trusted.
Furthermore, if breach of trust is broadly found, the whole
research community could fall under a cloud that maligns
everyone, generates counterproductive regulations, and fos-
ters widespread public doubt.
To take action in such cases requires courage and careful
preparation. The essential first step is to have already estab-
Chemical Engineering Education

lished a reputation of honor and standards. Then the process
must be carefully executed. The National Academy's re-
port'2' recommends:

1. Long before the need arises, establish your own credibility.
2. Discuss the case with a trusted friend or advisor.
3. Find out your institutional procedures by
Calling your academic Office for Research (Vice Provost?)
Reading the general publications listed in On Being a
4. Carefully choose the proper time to "put it in writing "-this
is a major step.
5. Seek confidentiality, but don't expect it. If you see a situation
coming, plan ahead.

On Being a Scientistt2] provides some excellent material
for engaging students in the issues explored here. The book-
let can be studied individually, in groups, or in a class. There
are nine short case studies given as sidebars in the main body
of the text, along with an appendix discussing them. The
case titles are:
Publication Practices
Credit Where Credit Is Due
Sharing of Research Materials
Fabrication in a Grant Application
A Conflict of Interest
Industrial Sponsorship of Academic Research
A Career in the Balance
The Selection of Data

Each case study has a brief background of the situation
with "real people" expressing opposite sides of the issues,
followed by one to three questions that attempt to bring out
the reader's view. The appendix provides some guidance, but
does not establish "the" answer.
I made use of the material in the context of the Departmen-
tal Graduate Seminar. First, I gave a talk that was essentially
the same as the text of this paper. After questions and a
discussion, I requested the departure of all those who were
not chemical engineering graduate students or who did not
wish to participate in a deeper experience of the issues. I
then asked the remaining students to break into groups of
three, and I gave each group a copy of one of the cases. They
were told that in three weeks, they would all be required to
present the Graduate Seminar under strict rules. Each group
would be given five minutes and four overheads to present
their case, which should include a description of the situa-
tion, the issues, and their own resolution of the case. I also
asked faculty members to volunteer as an advisor for each
case. The students were expected to meet with the faculty
member for discussion, and most of them did. Prior to this
exercise we had issued guidelines for oral communications
Fall 1997

(based on the AIChE Speaker's Manual) and the students
seemed to use this information to their advantage during
their preparations. To promote community feelings about
the effort and to provide a benchmark, I also gave out
"Speaker Evaluation" forms for the students to judge the
quality of my presentation. The compliments and criticisms
were consistent with my assessment of my talk.
The day of student presentations was an excellent occa-
sion. The seminar attendance was the largest in months, and
the presentations ranged from quite good to superb. Finally,
a survey of the students was taken about the difficulty of
understanding and resolving the cases-some proved harder
than others, but the students found all of them interest-
ing. The faculty said that some groups really "got into"
their cases, but no one was heard to say that the time and
effort were wasted.

This paper has tried to introduce "eager, thoughtful, and
reverent" workers to understanding and materials about tech-
nical research-what it is, why people do it, how it's done,
some of the difficulties, and what to do about unprofessional
conduct. Hopefully, some responsive chords have been struck.
Research is challenging; since we are involved with it, all of
its aspects should be of utmost importance to us.

The author is grateful for the encouragement of his col-
leagues, especially younger ones, to complete this work for

1. Holton, G., Einstein, History, and Other Passions, AIP Press,
Woodbury, NY (1995), especially pages 141-59, "Doing One's
2. On Being a Scientist: Responsible Conduct in Research, 2nd
ed. Committee on Science, Engineering and Public Policy of
the National Academy of Sciences, National Academy of
Engineering and Institute of Medicine. National Academy
Press (1995). Copies of this report can be ordered by calling
1-800-624-6242 or through the National Academy Press
website at
3. Sinderman, C.J., The Joy of Science: Excellence and Its
Rewards, Plenum, New York, NY (1985)
4. Medawar, P.D., Advice to a Young Scientist, Harper and
Row, New York, NY (1979)
5. "Conduct in Science," special section in Science, 268, 1705
6. Oliver, J.E., The Incomplete Guide to the Art of Discovery,
Columbia Press, New York, NY (1991)
7. Wilson, Jr., E.B., An Introduction to Scientific Research,
McGraw-Hill, New York, NY (1952)
8. American Scientist, 83(2), 116 (1995)
9. According to ChemTech, p. 26, February (1995)
Journals which often have articles of relevance to this topic
include ChemTech, published by the American Chemical
Society, Issues in Science and Technology, published by
National Academy Press, and Technology Review, published
by MIT Press. 0



Yale University New Haven, CT 06520-8286

he focus of the Yale University graduate course de-

scribed in this paper is on aspects of combustion not
usually part of the education of applied scientists or
engineers (especially mechanical and aerospace engineers).
Indeed, most available books in the field describe combus-
tion almost exclusively in terms of power production and/or
propulsion. These are, undeniably, areas in which combus-
tion is usually an attractive option. But as emphasized here,
combustion is also an extremely effective (and frequently
the most economical) way to synthesize and/or upgrade
needed materials.
Consider, for example, titania (white) pigment, briefly
discussed later in this article. Each year, megatons are sold
throughout the world at prices that exceed $1/kg. Most tita-
nia pigment is made by a chemical synthesis process involv-
ing combustion to generate high temperature oxygen and
water vapor that react with injected titanium tetrachloride
vapor to produce the desired pigment particles. More gener-
ally, it will be seen that not only are there many proven,
highly developed combustion processes for synthesizing com-
modity chemicals world wide, there are also new processes,
(some discovered only in the last ten years) that exploit
combustion. Examples are the production of diamond films
(Section 2.3) or fullerene molecules (C60, polymer of car-
bon) (Section 2.4).
Buckminsterfullerene, C60, is a completely novel (discov-
ered in 1985) and rather expensive ($10,000/kg in 1996)
polymorphh" of carbon that can be produced using benzene/
oxygen flames. It happens to be a form of carbon presently
"in search of applications." Not surprisingly, alternate syn-

Daniel E. Rosner is Professor and formerly Chair-
man of the Department of Chemical Engineering
at Yale University, where he also holds a joint
appointment in Mechanical Engineering. His re-
search activities include convective energy and
mass transport, interfacial chemical reactions,
phase transformations, gas dynamics, fine par-
ticle technology, and combustion-subjects on
which he has published over 230 papers and
one book, Transport Processes in Chemically
Reacting Flow Systems.
Copyright ChE Division ofASEE 1997

thesis and separation methods are very


Figure 1.
Orders of
magnitude of
< qchem>
in mixing-

e areas of re-

These relatively recent discoveries are now being exploited
and commercialized. Thus, an important point to make at the
outset is that there are not only mature technologies (con-
stantly in need of improvement to retain their competitive
edge) that exploit combustion to synthesize commodity
chemicals, but combustion is also an option for synthesizing
valuable new materials (films, fibers, particles, or molecules)
that will motivate synthesis-oriented combustion research
and development in the future.
In the graduate course described here, we have selected and
discussed several instructive examples of both mature and
recent materials synthesis technologies that exploit combus-
tion. In each case, valuable glimpses were provided of these
relevant issues: What are the current technological and com-
petitive challenges? What kinds of fuels, oxidizers, and addi-
tives are involved? What are the reagent contacting patterns?
How can such equipment be sized? What operating conditions
(pressure, temperature, composition, etc.) will be optimal?
Additionally, materials can be upgraded using combustion
techniques, i.e., there are many methods for cutting, resur-
facing, or otherwise changing the nature of materials using
combustion technology (Section 4). These examples, again,
lead to the conclusion that if you and your students or col-
leagues find yourselves thinking of combustion only in terms
of power generation and/or propulsion, you will inevitably
Chemical Engineering Education

1 PW/m3

condensed chemical explosives

1 TW/m3
space booster rocket,
-'"h.... in 1 atm flame
.----- modern gas turbine
1 GW/m3- 'V-2 rocket (alcohol/LOX)
SWhittle jet engine

1 MW/m3 PC power station

domestic oil burner

1 kW/m3

miss important opportunities. Indeed, much good research
and development will be needed on these nontraditional
(chemical engineering-) facets of combustion.
Another important purpose of this graduate course is
to give engineering students from different disciplines
an idea of how rather simple (preliminary) calculations
can be made to estimate approximately how large these
reactors must be in order to produce, say, a metric ton of
product every hour using, in some cases, conventional
types of combustion. For this purpose, frequent refer-
ence was made to the summary of attainable volumetric
chemical energy release rates shown in Figure 1. In-
structive student exercises were developed for each of
these topics. Students were asked to put in real numbers
and make the associated preliminary design calculations
as a necessary first step to the more detailed follow-on
calculations (often using proprietary codes). Each student
also researched and prepared a written term paper on a
particular combustion synthesis and materials processing
(CS/MP) topic of interest to him or her (see Table 1).
Several introductory lectures were devoted to com-
bustion fundamentals, including the chemical engineer-
ing core subjects of chemical thermodynamics and ho-
mogeneous/heterogeneous chemical kinetics. But CS/
MP examples were used to teach the principles of chemi-
cal thermodynamics and chemical kinetics, flame sta-
bility parametricc sensitivity), etc. Thus, we considered
the thermodynamics of diamond production (Section
2.3), and similarly, for chemical kinetics, we deliber-

inert gas-- =
absorption liquid-

bursling dl.c

Figure 2. --**
"Off-the-shelf" hydrochloric
reactor coaxial
via flame
H,(g) + Cl,(g) c2(g)
"diffusion H2(g)
flame." 1[3

Fall 1997

ately selected inorganic systems (e.g., the kinetics of Na(g) +
TiCl4(g)) (Section 2.1), and not the usual hydrocarbon chemistry.
In its original form, this course was comprised of a two-part
lecture each week for one semester (see Table 1). As done in this
summary, the examples were divided into the production of valu-
able vapors (e.g., HC1, SO2, (P205)2, 02, N2, etc.), fine particles
(carbon black, fumed silica, titania pigment, doped glass
microdroplets for optical waveguides, etc.), and monolithic solids,
all discussed later in this article. We went on to some interesting
combustion applications in the area of materials processing (coat-
ing, cladding, smoothing, cutting, slurry drying, etc.) and concluded
with remarks about the future importance of this less visible but
commercially important branch of combustion engineering.
Combustion Synthesis of Vapors

1.1 HCI Synthesis via H,(g) + Cl,(g)
An early "combustion-like" example I encountered for synthe-
sizing vapors is really a class of co-flowing non-premixed gas
burners. The reactor shown in Figure 2 can be purchased off-the-
shelf for combining hydrogen and chlorine to produce (and then to
condense) pure hydrochloric acid. In this way, one could specify

Organization of Graduate Course on Combustion for (Chemical-)
Synthesis and Materials Processing

Lecture # Topic(s)
1 Introduction to CS/MP: Course Scope, Fundamental/Technical
2 Review of Relevant Thermochemistry and Chemical Kinetics
3 Review of Essential Features of Combustion of Vapors, Liquids, and
Solids: Transport Phenomena in Pre-Mixed and Non-Premixed
4 Combustion-Synthesis of Valuable Vapors:
Acetylene, HC1, SO,, P,O, .
5 Combustion-Synthesis of Ultrafine Particles:
carbon black, fumed SiO,, TiO,
6 Combustion-Synthesis of Ultrafine Particles (continued):
doped SiO,, VO,-TiO, catalyst
7 Chemical Stability of Powders: "Pyrophoricity" and Ceramic
Monolith Synthesis via Powder Chemical Reactions ("SHS")
8 Combustion Synthesis of Coatings; e.g., diamond films
9 Combustion-Driven "Guns" for Applying Coatings:
Deton. Gun, HVOF Thermal Spray, ...
10 Combustion Surface Treatment: Flame 'Polishing,' Spheroidization,
Sintering, and Cladding
11 Oxy-Fuel Combustion for Cutting, 'Gas' Welding, and Brazing
12 "Submerged" Combustion for "Direct Contact" Heat/Mass Exchange:
Spray-drying of ceramic slurries, ...
Combustion as a Separation Technique:
U Recovery in Fluidized Beds, ...
13 Summary/Overview/Trends-Opportunities; Topics for Further

the indicated dimensions for the required burner-condenser
combination for synthesizing HCI from its elements. These are
indeed examples of combustion synthesis-one just has to
broaden one's notion of what is the "fuel" and what is the
"oxidizer," both gaseous in this instance.
1.2 Spray Combustion of S(1) and P(1)
A commercially important two-phase (liquid fuel) example,
familiar to many chemical engineers (and going back to
early in this century), is the use of a molten sulfur spray
combustor as one step in the ultimate production (via the
contact process) of the commodity chemical sulfuric acid.
The process,14' which even to this day is an eye-opener to
other engineers, involves melting sulfur, spraying the mol-
ten sulfur at 420K into a burner with dried air, and burning
the resulting sulfur droplets to form the intermediate product
SO2(g) (see Figure 3). The resulting SO2(g)/nitrogen stream
is first cooled and then oxidized to SO3(g) in a downstream
catalytic converter, and the SO3(g) is finally combined with
water in an absorber to produce sulfuric acid. This is, and
has been for most of this past century, the bread-and-butter
technique for making sulfuric acid. As a result, many chemi-
cal engineers are quite familiar with the burning of molten
sulfur, which may be regarded as an unusual fuel.
A similar example is the combustion of liquid phosphorus
for the ultimate production of phosphoric acid in support of
agricultural chemicals production. Thus, the burning of such
liquid fuels, 'weird' from the viewpoint of traditional com-
bustion engineers, has been part of the tradition of chemical
synthesis using combustion techniques for a long time.
1.3 Acetylene Synthesis via the Combustion-Driven Pyrolysis of CH4g)
An important technique for making acetylene (about one
Mt/y, worldwide) is really a rich preheated, premixed vapor
combustion process. The 1.4 atm vapor mixer-reactor is
shown schematically in Figure 4.[5 Some of the hydrocarbon
vapor (here, methane) is sacrificed (burned) to produce high
temperature methane-rich gas. The surviving methane is
then pyrolyzed to form acetylene, ethylene, soot, etc., in a
small plug-flow reaction space downstream of the block of

Figure 3. Synthesis of SO2(g) via molten sulfur spray
combustion as first step in the synthesizing the commod-
ity chemical: HSO4(1).'4

flame stabilizers, prior to a water (or oil) quench. With about
1-ms mean residence time at about 1800K, an acceptable
yield (about 24 wt pet. of the hydrocarbon feed) of acetylene
is achieved. Unfortunately, soot is an inevitable by-product
(about 5% yield), but acetylene is the principal goal. This
particular example is also useful to illustrate the principles
governing flame stabilization (i.e., what does it take to de-
sign a device that avoids extinction by blow-off, or poten-
tially dangerous flashback of these rich preheated/mixed
gaseous flames on such multi-hole, water cooled burners?).
1.4 Acetylene Synthesis via a "Submerged Flame" in Crude Oil
There is another interesting partial combustion method for
making acetylene at about 10% yield using pressurized oxy-
gen gas bubbling through hot liquid petroleum (crude oil),
i.e., the so-called "Submerged Flame" (also BASF) reac-
tor.151 In contrast to ordinary liquid fuel spray combustors, in
this class of reactors the (difficult to atomize) liquid fuel/
feedstock is the continuous (not dispersed) phase!
1.5 02(g) or N2(g) Generation from Decomposing Inorganic Solids
There is yet another important class of combustion-syn-
thesis gas generators that should be mentioned here: those
using the exothermic decomposition of an unstable solid
compound to generate the desired gas. One such example is
a type of oxygen generator used in many current aircraft.*
To design such a system, an appropriate oxygen-containing
compound (here, NaCIO3(s)) must be selected, formulated,
packaged, and ignited on demand. Of course, the resulting
dust-free oxygen must also be produced-released-delivered


@ ca. 900K Gas Mixer


Burner block Figure 4.
Smm Acetylene
SIV -F- synthesis
Reaction Methane
Reaction Cracking via
sa_ combustion-
I --- I driven
\ Water CH,(g)

SUnfortunately, this generator was involved in the recent fiery
crash of a ValueJet DC-9 aircraft (which was improperly
transporting more than fifty presumably expired versions of such
Chemical Engineering Education

in a reasonable length of time. In this case the ignition
process involves the sudden mixing of a fine iron powder
with the sodium chlorate. When the second main 02 genera-
tor (based on the electrolysis of waste water) on the Russian
Mir space station failed (August 5, 1997), the crew was
forced to rely on "chemical" 02 from canisters filled with
lithium perchlorate, some 70 of which were kept on board
for just such an occasion. Earlier, the failure of one such
canister (in February, '97) had caused a smoke-fume emer-
gency for the astronauts on board.
A generically similar and commercially important example
is the so-called automotive airbag system, which also served
as the basis for several instructive student calculations re-
lated to boundary conditions""6-7 and ignition. This is a
compact device in which sodium azide, NaN3(s), an unstable
solid compound rich in the element nitrogen, is ignited in
response to the vehicle deceleration. The decomposing solid
propellant, which also contains an oxidizer (e.g., about 30
wt. pet. KCO13(s) or NaNO3(s)) generates the hot nitrogen
gas that inflates-deploys the bag in the automobile cabin,
thereby protecting the onrushing passenger. Providing auto-
motive air bags (front and side) that are safe and environ-
mentally friendly is a large and growing industry around the
world. Indeed, companies prominent in the automotive air-
bag inflator business are or were chemical-propulsion ori-
ented (solid propellant) companies.
Combustion Synthesis of Fine Particles and Coatings

2.1 Carbon Black, Fumed Silica, Titania Pigment, TiB2(s) Nano-Spherules
Combustion is now routinely used to generate ultra-fine
particles (e.g., pigments, adsorbents, or viscosity modifi-
ers[8'91). These are frequently particles with remarkably high
surface area per unit volume or mass, i.e., their constituent
spherules are very small. Carbon black and ordinary soot are
comprised of aggregates with spherules only tens of nanom-
eters in diameter, so that the corresponding area per gram is
hundreds of square meters! Carbon black is used as a pig-
ment or as an additive to improve wear characteristics (e.g.,
synthetic rubber tires). Of course, optimizing the nature of
the carbon black (surface chemistry and morphology) de-
pends on the specific application, and involves controlling
the surfaces of the carbon particles themselves.
The titania industry mentioned above is also a mature one,
with the original chloride-process patents going back to
DuPont in the 1940s. In the case of titania pigment pro-
cesses, the feed is usually impure TiO2(s) (rutile ore). This is
chlorinated in the presence of coke to generate titanium
tetrachloride vapor on site using chlorine vapor in a fluid-
ized bed reactor. This titanium tetrachloride is ultimately fed
to an oxidation or hydrolysis reactor that is frequently the
hot-oxygen effluent of a high-pressure, turbulent, liquid hy-
drocarbon fuel-lean spray combustor in co-flowing oxygen
Fall 1997

(with, perhaps, water vapor added). In the tandem turbulent
mixer-reactor, one oxidizes the titanium chloride, and nucle-
ates/grows the titanium oxide particles. For pigment par-
ticles there must be enough residence time in this reactor
(and in downstream tubing) to grow the coagulating par-
ticles into the pigment size range spherulee diameters roughly
equal to the wave length of visible light).
Much of the titania marketed around the world is made by
this chloride process-incrementally improved on a con-
tinuing basis but apparently hard to replace with a more
economical alternative. What differs from company to com-
pany are such details as what the quality of the input rutile
must be, what additives are used to control the coagulation
process, and how to control the bond strength between the
primary particles, etc. It remains to be seen whether the
presently accepted concepts of turbulent mixing and particle
production in turbulent non-premixed flows can be used to
provide useful predictions of the resulting size distribution
and evolution of particles in these complex environments.
Incidentally, this is another illustration of where, because of
the demands of industrial productivity, suspended particle
mass fractions are not negligibly small (in many environ-
mental applications of aerosol science, particle mass frac-
tions are less than 0.1 pet.). As in the case of the optical
wave guide application110 described briefly below (Section
2.2), the mass fraction of the particles being produced and
collected is appreciable (about 25 wt. pet.).
The most recent International Combustion Symposia con-
tain several interesting papers on gas phase combustion meth-
ods to synthesize valuable condensed products.1 '13 For ex-
ample, DeFaux and Axelbaumt121 describe a method for pro-
ducing coated nano spherules of titanium diboride using a
co-flowing vapor axisymmetric burner for reacting sodium
vapor with a mixture of titanium tetrachloride and boron
trichloride, with argon serving as the carrier gas. The sodium
chloride subsequently condenses on the TiB2(s) particles, in
effect preventing the spherules from binding tightly together.
These sodium chloride coatings can then be dissolved away
in a post-processing step.
2.2 Doped Glass Microdroplets for Optical Waveguide Fiber Synthesis
Currently used processes for making continuous optical
wave guide glass fiber (see Figures 5a,b, next page) also
make use of combustion-generated particles. In such cases,
the burner frequently uses methane or hydrogen fuel. The
oxy-fuel flame is 'doped' not only with a precursor of silica,
but also phosphorous-, germanium-, and boron-containing
vapors. Such seeded flames produce a high temperature mist
of doped silica submicron droplets. By controlling the (phos-
phorus, germanium, boron, etc.) dopant flow rates, one can
control the refractive index of the resulting particles and, by
gradually changing the ratios of those dopant compounds in
the burner, one can produce microdroplets with different
refractive indices. These deposit at different depths in a

cooler preform to produce a porous glass deposit with a
built-in refractive index gradient. This soot preform is then
pulled through a furnace to produce kilometers of OWG
fiber, about 125 gm diameter. Not surprisingly, there are
several variants of this process around the world. The par-
ticular one sketched in Figure 5a is essentially the Coming
method. Nippon Telegraph uses a version (Figure 5b) in
which the preform is spinning and pulled vertically through
a furnace. One (or more) burner(s) produces and deposits the
particles on the end of the withdrawn target (as opposed to
the Coming process, where the burner basically moves back
and forth relative to the spinning but otherwise fixed pre-
form). An interesting feature of this class of applications is
the simultaneous role of high particle mass loading and
submicron particle transport dominated by the "non-Brown-
ian" mechanism of thermophoresis.' 10,15]

2.3 Combustion Synthesis of Diamond Films
Since the startling report of Hirose,[161 combustion has also
been used to grow high-quality diamond films on hot (about
1200K) substrates, even at one atmosphere pressure! Whereas
thermodynamically, this result was certainly not anticipated,
it turns out that within a narrow range of flame stoichiometry
and substrate temperatures one can grow about 20 microme-
ter crystallite-sized polycrystalline diamond films at rates up
to about 200 um/h from, say, low-pressure rich acetylene/
oxygen flames. This is apparently because such flames con-
tain large concentrations of methyl radicals and atomic hy-
drogen-but diamond films can be grown even if one just
generates (via electrical discharge or laser-heated graphite)
C atoms or C2 molecules. Not surprisingly, the interfacial
chemical kinetics are not fully understood. But the combus-
tion method is simple and has been used to obtain rapid
diamond film growth rates with areas up to about 100 cm2 on
the substrates Si, Mo, A1203, and TiN.E171

2.4 Combustion Synthesis of Fullerenes and "Nano-Tubes"
Combustion (e.g., premixed O,/benzene at 100 torr) has
also been used for synthesizing the so-called
Buckminsterfullerene molecule: C60-a polyatomic carbon
'soccerball.'[8-20] With a diameter of only 0.71 nm, each of
these objects can be regarded either as a high molecular
weight "vapor" molecule (see Section 1), or as a "nano-
particle" (this Section). In 1996, research quantities of C60
were selling for about 0.1 M$/kg. While the mechanisms of
flame-generated C60, C70, and soot-formation may have some
features in common, optimum C60 yields (reported to be of
the order of 0.5 wt. pet. of the fuel carbon) appear to require
both high temperatures (more than 2100K) and low pres-
sures, and the chemical route to Co appears to require the
formation of vibrationally excited polycyclic aromatic hy-
drocarbon (PAH) molecules containing 5-member rings.' 81
Recently, close-packed bundles of carbon nanotubes have
been synthesized using the laser ablation of graphite. Each

such nanotube is a sheet of hexagonally bonded carbon
rolled up into a seamless cylinder, capped at both ends with
semi-fullerene molecules! It remains to be seen whether
controlled combustion techniques can be developed to eco-
nomically synthesize such interesting structures.
Synthesis of Monolithic Solids via Combustion of Powders

3.1 Self-Propagating High Temperature Synthesis (SHS)
Unconsolidated powder blends (e.g., Ti(s) + 2B(s), or
Ti(s) + C(s)) can be ignited at one end to form blocks of
useful but somewhat porous ceramic materials (e.g., TiB2(s)
or TiC(s)) by a method sometimes called a "solid flame,"
"gasless combustion," or "self-propagating high tempera-
ture synthesis" (SHS).[21'221 Indeed, SHS (investigated exten-
sively in Russia since 19671231) is sometimes (erroneously)
thought to be the principal application of combustion to
materials synthesis. This thermite-type process has also been
used for welding materials together, often in the field, and
(with the help of centrifugation) for putting refractory coat-
ings on the inside of large cylindrical pipes. Not surpris-
ingly, wave propagation speeds, often of the order of centi-
meters per second, are system-specific and powder-grain-
size dependent. Only now are mechanistically realistic flame
theories being developed and applied to these pseudo-
premixed flame propagation problems.

3.2 Other Examples of Solid Combustion Synthesis
Garnet luminescent phosphors with submicron particle
size for, say, field-emission displays (television screens, etc.)
can be synthesized by combusting powders, although the
mode of combustion is not self-propagating and the product
may itself be a powder (e.g., Eu2+-doped Y203 phosphors via
the reaction of metal nitrates (oxidizer) with organic fuel
(urea, carbohydrazide, glycine) at 773K241).

Figure 5a,b.
Optical wave
flames. [14]

Chemical Engineering Education

REACTANTS ---- CH4(g) 02 (9) '
SICI4(g)... '
BURb \' F ',RAE
7USo N

a) 'OVD'




b) 'VAD'

H2(g), 02 (g)

Combustion for Materials Processing (MP)

Materials synthesized by many other techniques are often
modified (upgraded) using some form of combustion device.
Several interesting examples are outlined below, with em-
phasis on more recent or, perhaps, less familiar cases.
4.1 Combustion-Driven "Guns"for Depositing Coatings
Figure 6 (schematically) shows a steady flow particle ac-
celerator based on liquid-fueled rocket combustor technol-
ogy.[25' This so-called jet (J-) gun is really a miniature liquid-
propellant rocket motor except that for a real rocket motor
(whose purpose is a compact thruster), one might select
liquid oxygen (LOX) as the oxidizer and operate at chamber
pressures far in excess of 9.2 atm. But in a ground-based
laboratory for coating, say, turbine parts, one can use gas-
eous oxygen from cylinders. This oxygen and some conve-
nient liquid fuel (here kerosene) are fed into a small water-
cooled moderate-pressure combustion chamber-nozzle com-



Figure 6. Rocket-type jet (J-) gun for depositing refrac-
tory coatings on downstream workpieces.251

Figure 7. Detonation (D-) gun for accelerating powders to
deposit coatings on downstream workpieces. 26

"' Detonation --


Figure 8. Solid-propellant-driven cladding technique
(schematic of typical arrangement).
Fall 1997

bination, for the purpose of creating a supersonic exhaust jet
of hot gaseous combustion products. This jet is used to
accelerate (to about 1 km/s) and heat the powders put into
suspension, e.g., 20- um diameter tungsten carbide. Particle
impaction on the target placed downstream results in the
desired coating (e.g., thermal- or erosion-barrier, perhaps
250 pm thick). These high-velocity oxy-fuel (HVOF) coat-
ing devices are not terribly energy efficient-they heat up a
great deal of water, but they accomplish their purpose (add-
ing value to the target) at an acceptable total cost. Several
student exercises were developed to address the optimum
conditions for accelerating and heating such particles. With
a typical system, including the jet gun itself, a powder feeder,
a tank of liquid fuel, and oxygen gas cylinders, it is possible
to coat a wide variety of materials placed immediately down-
stream in the rocket+particle accelerator exhaust.
A rather different type of combustion gun, which is inter-
mittent, is the detonation (D-) gun (see Figure 71261). Here,
repetitive H2(g)/O,(g) detonations are propagated through a
suspended powder and each detonation wave acts like a
piston to propel the hot particles onto the workpiece. This
process is repeated about every 1/6 of a second. Praxair
(formerly Union Carbide) Surface Technologies has a pro-
prietary coating business based on the D-gun. This device is
an excellent vehicle to teach the theory of detonations-viz.,
supersonic combustion waves that produce high pressures
and temperatures behind them. Accordingly, they are ca-
pable of heating and accelerating particles suspended in the
combustible gas mixture. Note that the pressure vessel is,
indeed, like a gun barrel-with repetitive spark-ignited oxy-
hydrogen detonations that shoot each fresh charge of sus-
pended particles out onto the target. Using the principles of
detonation theory, and the heat/momentum/mass transfer
properties of the suspended particles, each engineering stu-
dent can go through the steps of designing such a gun. This
includes sizing, determining how rapidly it can be fired and
reloaded, what kind of coating rates are achievable, etc.
These are instructive, yet conceptually simple, calculations
for engineering students.
The reader probably already suspects that it is possible to
carry out many types of explosive processing for the clad-
ding or (re-)shaping of materials. For example, to clad one
material onto the surface of another (substrate) without the
need for a huge mechanical press, it is possible to assemble a
sandwich of the ingredients on an anvil, with a sheet of solid
propellant above the cladding material (see Figure 8). Upon
igniting the solid propellant, a propagating detonation slams
these two materials together. Many controlled explosive pro-
cedures of this type are being used for cladding, shaping, or
sintering materials, including powdered metals.
4.2 Combustion-Driven Cutting or "Gas" Welding Operations
Most engineers are already familiar with the fact that
gaseous acetylene/oxygen flames are hot enough (about

3500K at 1 atm) and compact enough to provide local work-
piece heat fluxes (more than 3 MW/m2) adequate for cutting
or welding operations on metal sheet materials. Indeed, by
combining the principles of turbulent jet mixing and convec-
tive heat transfer with a steady-flow energy balance, engi-
neering students can make useful estimates of torch require-
ments and attainable cutting or welding rates (crucial topics
often not even present in handbook accounts of these opera-
tions). Perhaps less familiar is the fact that after localized
work-piece heat-up, for several important metals (including
iron and titanium alloys) the fuel supply can actually be cut
off completely and metal combustion (with molten metal
oxide runoff) alone will continue the cutting operation! This
cutting technology, in which an acceptably small fraction of
the workpiece becomes the fuel, is not new (Air Products
Corporation was supplying such O2(g) lances in 1941 and
such an example is shown in the introduction of Spalding's
convective mass-transfer textbook,1271 but this type of microjet
"oxygen lance cutting" certainly deserves attention in this
short CMP-review.
4.3 Surface Treatments: Flame Polishing, Spheroidizing, etc.
Another noteworthy MP example in which combustion is
conveniently used is surface (fire-) polishing. For example,
could you predict how long it would take to smooth an
initially rough metal or ceramic surface by the mechanism of
surface-energy (curvature) driven surface diffusion using a
high temperature torch? Can you design an economical pro-
cess using hot combustion products to spheroidize a powder
that presently has poor flow characteristics because of ir-
regular grain shape?
Changing near-surface compositions (hence properties) by
metal workpiece exposure to tailored combustion-product
environments (e.g., containing ammonia, devoid of SO2,
CO2, and H20, etc.) is also a widely used technique for the
nitriding, carburizing, carbo-nitriding, etc., of ferrous and
nonferrous metals.1281 Many of these practical examples can
be used to teach the principles of transient one-dimensional
Fickian solute diffusion. This includes calculations of the
required process time at temperature, again without recourse
to proprietary (black-box) computer codes.

Other important CS/MP examples were used in the course,
including (for the MP segment) combustion-driven spray
drying of ceramic slurries and submerged burners for heat-
ing aggressive molten baths. But the particular examples
selected above will be sufficient for our present introductory
purposes. In principle, the instructor will have little diffi-
culty finding yet others, perhaps better suited to the back-
ground of an individual class. Unfortunately, however, there
is not yet any coherent account of this overall subject that
can be used as a textbook for a CS/MP course-a situation
that motivates the writer to embark on this project.12] Useful

information on many of the individual chemical processes
included here can be found in the chemical engineering
encyclopedias: Kirk-Othmerl51 and/or Ullmanss51. But, of
course, proprietary details are, at best, found only in the
patent literature. For the underlying transport and combus-
tion principles, the situation is much better-for this course I
simply used my review papers,'I629] Rosner and
Papadopoulos,t11 and the 3rd printing of my 1986 textbook
Transport Processes in Chemically Reacting Flow Systems, 71
which most Yale students already had. (A second edition
should be available, with additional CS/MP content, by 1998-
9.) Other recent, readable accounts of the fundamentals of
combustion 301 were put on reserve in the Engineering Library.
Pedagogically, for teaching the principles of thermody-
namics, chemical kinetics, gas-dynamics, mixing, chemical
reactor design, detonations, materials science, etc., engineer-
ing students from many disciplines can relate to the practical
yet extraordinary examples above. They transcend the tradi-
tional power generation/propulsion combustion topics and
are, accordingly, appealing to broaden our perspective. In-
deed, for graduate students, many of these examples will
also suggest interesting, perhaps hitherto intractable, research
projects that probably could be tackled now. I hope these
representative examples convince the reader once and for all
that combustion is not limited to power generation/propul-
sion or process heat, and that there are many both mature
and/or evolving technologies in which combustion can be
used to produce very valuable materials (in some cases worth
thousands of dollars per kilogram). This class of combustion
applications also forces the engineer to broaden his or her
conception of what is a useful fuel and what is a useful
oxidizer, and to consider contacting and mixing configura-
tions that are, more often than not, rather different from the
canonical ones displayed in most combustion textbooks.
It is also evident from these CS/MP topics that if you are
trying to optimize a combustion reactor process for, say,
diamond film growth, you would be well advised to team up
with materials scientists who can characterize such deposits
and the prepared substrate, flame chemists, and experts in
flame aerodynamics and transport phenomena. Thus, while
chemical engineers are in an extraordinarily strong position
to contribute, an interdisciplinary attack will probably be
essential for success in the CS/MP arena.
As summarized above, in this graduate course we consid-
ered interesting practical examples where further combus-
tion research may, in fact, make combustion the most attrac-
tive route to synthesizing and/or processing valuable new
materials, rather than (as is sometimes the case) a cheap but
still poorly understood or controlled alternative.
We also demonstrated that with simple rate-controlling
postulates, it is usually possible to estimate the size and
performance of the required equipment. Needless to say, in
any particular case, this would be the logical first step before
Chemical Engineering Education

going to more elaborate, often proprietary or black-box,
computer models. In the writer's opinion, from a pedagogi-
cal point of view, this is a healthy and confidence-building
orientation for engineering students, too often neglected.
Moreover, to design processes that are intrinsically novel,
chances are that the packaged programs commercially avail-
able do not anticipate the circumstances of present interest!
To conclude, many readers will appreciate that there are
also many attractive research topics lurking among these
examples.3'32] Especially if you have not been thinking along
these lines, I commend them to your attention as viable and
healthy directions for combustion research to take in the

It is a pleasure to acknowledge the helpful comments and feed-
back of P. Benedek, K. Brezinsky, H.F. Calcote, J.B. Fenn, A.
Gomez, M. Frenklach, I. Glassman, S.A. Gokoglu, J. L. Katz, M.K.
King, A.G. Konstandopoulos, S.E. Pratsinis, R.C. Tucker, Jr., and
G.D. Ulrich on some of these synthesis/materials processing facets
of combustion engineering. The author's CS/MP research is carried
out at the Yale Center for Combustion Studies and the Yale High
Temperature Chemical Reaction Engineering (HTCRE) Labora-

EDITOR'S NOTE: Due to space restrictions, we were not able
to include several instructive student exercises. They will be
published in the next (Winter '98) issue of CEE.

1. Rosner, D.E., and D. Papadopoulos, "Jump-, Slip-, and Creep-
Boundary Conditions at Gas/Solid Interfaces," I/EC Res.,
35(9), 3210 (1996)
2. Rosner, D.E., "Combustion Synthesis and Materials Pro-
cessing," NASA Lewis Research Center Short Course
(Microgravity Combustion and Materials Sci/Technology
Branches), June (1996); Extended short course notes, July
4, (1966); Monograph in preparation (1997)
3. Sigri Elektrographit GmbH product literature
4. Killifer, D.H., Chemical Engineering, Amer. Chem. Soc.,
Washington, DC, 85 (1975)
5. Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd
ed., Wiley, New York, NY (1978); also Ullmans Encyclope-
dia of Industrial Chemistry, VCH Publishers (1994)
6. Rosner, D.E., "Energy, Mass, and Momentum Transport:
The Treatment of Jump Conditions at Phase Boundaries
and Fluid Dynamic Discontinuities," Chem. Eng. Ed., 10,
190 (1976)
7. Rosner. D.E., Transport Processes in Chemically Reacting
Flow Systems, Butterworth-Heinemann (1986, 1988, 1990)
8. Ulrich, G.D., "Flame Synthesis of Fine Particles," C/E News,
62(32), 22 (1984)
9. Pratsinis, S.E., "Review of Combustion-Generated Aerosol
Formation," Prog. Energy Comb. Sci., (in press) (1997); see
also Zachariah, M., "Understanding and Controlling Par-
ticle Growth," Invited Paper, Eastern States Comb. Inst.
Mtg., Fall (1996)
10. Rosner, D.E., and H.M. Park, "Thermophoretically Aug-
mented Mass-, Momentum-, and Energy-Transfer Rates in
High Particle Mass-Loaded Laminar Forced Convection Sys-
Fall 1997

teams Chem. Eng. Sci., 43(10), 2689 (1988)
11. Calcote, H.F., and W. Felder, "A New Gas-Phase Combus-
tion Synthesis Process for Pure Metal, Alloys, and Ceram-
ics," 24th Int. Combustion Symposium, Combustion Inst.,
Pittsburgh, PA, 1869 (1992)
12. DeFaux, D.P., and R.L. Axelbaum, "Nano-Scale
Unagglomerated Non-Oxide Particles from a Sodium Co-
Flow Flame," 25th Int. Combustion Symposium, Combus-
tion Inst., Pittsburgh, PA (1994); reported in Comb. & Flame,
13. Brezinsky, K., "Gas Phase Combustion Synthesis of Materi-
als," 26th Int. Combustion Symposium, Combustion Inst.,
Pittsburgh, PA, 1805 (1996)
14. Bautista, J.R., K.L. Walker, and R.M. Atkins, "Modeling
Heat and Mass Transfer in Optical Waveguide Manufac-
ture," Chem. Eng. Prog., p. 47 (Feb. 1990); also, Senior, C.L.,
"Manufacture of Optical Waveguides Using Aerosols: A Re-
view," Particle Sci. Tech., 5, 13 (1987)
15. Gomez, A., and D.E. Rosner, "Thermophoretic Effects on
Particles in Counterflow Laminar Diffusion Flames," Comb.
Sci. Tech., 89, 335 (1993)
16. Hirose, Y., 1st Int. Conf. New Diamond Sci. Tech., Japanese
New Diamond Forum, 38 (1988)
17. Liu, H., and D.S. Dandy, Diamond CVD-Nucleation and
Early Growth Stages, Noyes (Park Ridge, NJ) (1995)
18. Howard, J.B., "Fullerenes Formation in Flames," 24th Int.
Combustion Symposium, Combustion Inst., Pittsburgh, PA,
19. Dresselhaus, M.S., G. Dresselhaus, and P.C. Eklund, Sci-
ence ofFullerenes and Carbon Nano-Tubes, Academic Press,
New York, NY (1996)
20. Kadish, K.M., and R.S. Ruoff, Recent Advances in the Chem-
istry and Physics of Fullerenes and Related Materials, Elec-
trochemical Soc., Pennington, NJ., Proc. Vol. 94-24 (1944)
21. Hlavacek. V., "Combustion Synthesis: A Historical Perspec-
tive," Amer. Ceramic Soc. Bull., 70, 240 (1991)
22. Varma, A., and J-P Lebrat, "Combustion Synthesis of Ad-
vanced Materials," Chem. Eng. Sci., 47(9-11), 2179 (1992)
23. Merzhanov. A.G., "Solid Flames: Discoveries, Concepts, and
Horizons," Comb. Sci. Tech., 98, 307 (1994)
24. Shea, L.E., J. McKittrick, O.A. Lopez, and E. Sluzky, "Syn-
thesis of Red-Emitting Small Particle Size Luminescent
Oxides Using an Optimized Combustion Process," J. Amer.
Ceramics Soc. (in press, 1996)
25. Tafa, H., Technologies Inc., Concord, New Hampshire (1991);
Technical Data HP/HVOF "Thermal Spray" System; See
also Brown, A.S., in Aerospace America, 52, (January 1992)
26. Praxair Surface Technologies, Indianapolis, IN 46224 (for-
merly Union Carbide Coating Service), R.C. Tucker, Jr.,
private communication (1992)
27. Spalding, D.B., Convective Mass Transfer, McGraw-Hill,
New York, NY, 7 (1963)
28. Pritchard, R., J.J. Guy, and N.E. Conner, Handbook of
Industrial Gas Utilization, Van Nostrand-Reinhold, New
York, NY, Chap. 13 (1977)
29. Rosner, D.E., "A Course in Combustion Science and Tech-
nology," Chem. Eng. Ed., 14, 193 (1980)
30. Lifian, A., and F.A. Williams, Fundamental Aspects of Com-
bustion, Oxford Press #34, Engineering Science Series (1993)
31. Rulison, A.J., P.F. Miquel, and J.L. Katz, "Titania and Silica
Powders Produced in a Counterflow Diffusion Flame," J.
Mater. Res., 11(12), 3083 (1996)
32. Xing, Y., U.O. Koylu, and D.E. Rosner, "Synthesis and Re-
structuring of Inorganic Nano-Particles in Counterflow Dif-
fusion Flames," Comb. & Flame, 107, 85 (1996); see also
AIChE J., (Special Ceramics Processing Issue) in press,
Fall (1997) 0




University of California Los Angeles, CA 90095

n modern chemical engineering, environmental issues
contribute significantly to process design and operation.
Consequently, curricular changes must be made to in-
corporate new approaches and examples that illustrate con-
cepts related to the protection of the environment.
Combustion is an excellent example of applied high-tem-
perature reaction engineering where thoughtful compromises
should be made between pollutant formation and power
generation. Combustion is also a widely used process,
with applications ranging from space heating to automo-
tive and air transportation, and is the major contributor to
air pollution. Consequently, students can easily relate to
many environmental issues associated with combustion
technologies-for example, the formation of nitrogen
oxides (NOx) and soot.
While senior chemical engineering students are well aware
that the oxidation of hydrocarbon fuels produces carbon
dioxide and water as the major products, however, they are
not familiar with the fact that hundreds of trace by-products
are also routinely formed in combustion and that combustion
conditions cannot simply be altered to minimize the emis-
sion of all pollutants. In Figure 1, the levels of thermal NO,
and hydrocarbon by-products formed in combustion are pre-
sented as a function of fuel-air equivalence ratio. Equiva-
lence ratio, p, is defined as the actual fuel/air ratio used
divided by the fuel/air ratio corresponding to stoichiometric

(fuel/ air)act
(fuel / air)stoich

Figure 1 shows that NO, emissions formed as a conse-
quence of the reactions of N2 exhibit a maximum near sto-
ichiometric conditions due to high flame temperatures and
decrease rapidly at higher and lower equivalence ratios when
temperatures decrease because of the presence of excess fuel
and air, respectively. Lower temperatures, however, re-
duce reaction rates and result in the emission of un-
burned hydrocarbons from combustion systems. Conse-

quently, careful compromises must be made between NOx
and hydrocarbon emissions.
When heat recovery is necessary, such as in heaters and
boilers, a section of the combustion device is operated under
fuel-rich conditions to promote radiative heat transfer from
gases. The fuel-rich stage is then followed by a fuel-lean
stage in order to fully oxidize unburned hydrocarbons. This
"two-stage" combustion is widely used today to minimize
both thermal NO, and hydrocarbon emissions.[~I In addition,
control technologies, such as catalytic converters, may also
be required to meet emissions standards.
Among the hydrocarbons emitted from combustion pro-
cesses, polyaromatic hydrocarbons (PAH) are of particular
concern due to the potential mutagenicity and carcinogenic-
ity of some of their isomers.[21 PAH are also believed to be
precursors to soot, the formation of which represents a loss
in combustion efficiency and is a significant environmental
problem by itself. Although PAH are emitted at trace levels,
on the order of parts per billion by volume (ppbv) to parts
per million by volume (ppmv), they often represent the
greatest health risk associated with combustion systems.[3.41
Therefore, the development of combustion technologies
and/or operation strategies that will reduce these emis-
sions, together with NO, emissions, continues to be of
significant practical interest.
Combustion devices generally operate under conditions in
which the oxidizer (air) and fuel are not mixed prior to

Keith Fordon is a development engineer in the Department of Chemi-
cal Engineering at UCLA. He earned his BS with honors in chemical
engineering from UCLA in 1993.
Antonio Vincitore is a PhD candidate in the Department of Chemical
Engineering at UCLA. He received his BS in chemical engineering
from Manhattan College in 1992. His research has been focused on
PAH formation in hydrocarbon flames.
Selim Senkan is Professor of Chemical Engineering at UCLA. He
received his BS from METU, Turkey, and his MS and PhD from
Massachusetts Institute of Technology. His research interests are in
chemical reaction engineering, combustion, and laser diagnostics.

Copyright ChE Division ofASEE 1997
Chemical Engineering Education

reaction. Consequently, diffusion flames dominate the mode
of burning. At UCLA, we implemented an opposed jet burner
system that mimics the diffusion flames encountered in prac-
tical combustion devices. In this system, the oxidizer and
fuel move in an opposed flow configuration, whereby the
combustion reaction occurs in a flat flame near the stagna-
tion plane. Because this flow field has a central axis of
symmetry, the quantitative chemical composition of the flame
can be readily determined by withdrawing samples along the
central longitudinal axis of the burners.
Prior to the experiment, students attend lectures that em-
phasize the effect of fluid dynamic residence time and mix-
ing on pollutant formation
within diffusion flame struc-
tures, coupled with a fluid dy- Therr
namic analysis of the Navier-
Stokes equations describing the
flow field encountered in the
opposed flow experiment. In
addition to a discussion of the
relevant transport phenomena, o
various chemical pathways, *
such as those involved in the \
formation of benzene and PAH,
and in the oxidation of meth-
ane to carbon monoxide, are
reviewed.5" For example, stu-
dents are introduced to both
"even" and "odd" number car-
bon reaction pathways that lead
to the formation of aromatics
within hydrocarbon flames. quiv
The following even-number gure 1. The depend
carbon pathway describes the emissions on
formation of the first benzene
ring at low temperatures:
C2H2+C2H3 =n-C4H5
C2H2 + n C4H5 = CH6 + H
where C2H2 is produced as a result of a sequence of dehydro-
genation reactions, such as

C2H6 + H = C2H5 + H2
C2H5 = C2H4 + H
C2H4 + H = C2H3 +H2
C2H3 = C2H2 + H

In the odd-number carbon reaction route, benzene has
been proposed to form via
C3H3+C3H3 =C6H5+H
followed by the hydrogenation of the phenyl radical
C6H5 +CH4 =C6H6 + CH3
The C3H3 radicals are produced by the addition of a singlet
Fall 1997

methylene radical, CH2(s), to acetylene:
CH2(s)+ C2H2 = C3H3 + H
Similar pathways for the formation of PAH are also re-
viewed. At the end of a two-week work period, students
write a final report discussing the effects of fluid dynam-
ics, fuel structure, dilution, and other process conditions
on the formation of pollutants in hydrocarbon flames.
They also present their work orally in front of other
groups and selected faculty.


An illustration of the



experimental burner system and
sampling configuration is

shown in Figure 2 (next page).
lOx The flame was stabilized be-
tween two opposed 1.0-inch
I.D. burner ports. The flows
Hs of oxidizer and fuel gases
were regulated using mass
flow controllers. The oxidizer
stream was introduced
through the top burner port
and the fuel stream was intro-
duced through the bottom
burner port. Argon diluent
was used in the fuel stream to
control the flame temperature.
The flame was protected from
ambient air by an argon shield
gas. The shield gas also aided
ce Rt, in cooling the hot combus-
ce Ratio, 4
tion products. All gases were
ofNO, and hydrocarbon vented through the water-
ivalence ratio. cooled heat exchanger that
was built around the bottom
burner.181 The arm supporting the top burner was simi-
larly water-cooled (not shown).
In the present experiment, the distance between the burner
ports was 1.8 cm, the oxidizer stream was air at a flow rate of
5.8 L/min, and the fuel stream was a CH4/Ar mix (75% by
volume CH4 and 25% by volume Ar) at a flow rate of 4.0 L/
min. This corresponds to an overall equivalence ratio sig-
nificantly greater than one (4 = 4.9). We chose this condition
to increase the emission of products of incomplete combus-
tion from the burner system.
Visually, the flame exhibited blue, luminous yellow, and
dark orange zones characteristic of a diffusion flame, with
the flame being positioned on the oxidizer side of the stagna-
tion plane, as illustrated in Figure 3 (next page). Since oxy-
gen was the limiting reactant, methane necessarily diffused
across the stagnation plane into the oxidizer side. The blue
zone marked the occurrence of reactions associated with
stoichiometric flames. In addition, a dark zone, located be-

tween the blue and luminous yellow zones, was noted by
the students during the experiment.191 The luminous yel-
low and dark orange zones indicated the presence of
higher molecular weight hydrocarbons and the formation
of soot particles or precursors.
Samples were withdrawn via a heated quartz microprobe
having a 100 tm orifice at its tapered tip and transported
through a silica-lined, stainless steel transfer line to the
Hewlett-Packard (HP) 5890 II gas chromatograph (GC).
Light gases were separated by Hayesep DB and Hayesep T
packed GC columns and detected with a thermal conductiv-
ity detector (TCD). Heavier gases were separated by an HP-
5MS capillary column and detected with an HP 5971A mass
selective detector (MSD). The entire sampling system was
maintained at 3000C and subambient pressure to minimize
the adsorption of PAH with five rings or less. Mole fraction
profiles were generated by moving the entire burner assem-
bly relative to the fixed sampling probe. Temperature mea-
surements were made in a similar fashion with a silica-
coated 0.15 mm Pt-13%Rh/Pt thermocouple.

This experiment presents obvious safety concerns. High
flame temperatures (12000C) and sampling system tempera-
tures (3000C) must be handled with extreme care. The fuel
gas used is flammable, and poisonous by-products such as
CO are produced. Therefore, many safety features have been
incorporated into both the design and the construction of the
experimental facility and student operating procedures.
Contact with the burners or the sampling line must be
avoided during the course of the experiment. The surface
temperatures of the burners were kept sufficiently low by

Mass Spectrometer
Data Analysis

Figure 2. Experimental set and sampling configuration.

both the shield gas and water cooling. The sampling line was
insulated. Although the combustion products were vented
through the bottom burner, an overhead fume hood was
constructed on top of the experiment to increase safety. As a
final safeguard, a carbon monoxide detector was installed.
With the potential hazards in mind, an experienced teach-
ing assistant checks the oxidier and fuel flow rates before the
flame is lit. In addition to the mass flow controller displays,
rotameters were installed to provide further visual indication
of the flow rates. The flow of both oxidizer and methane
can be ceased at any time with manual shut-off valves.
Students are taught the safe start-up and shutdown proce-
dures. Gas flows must be turned on sequentially in the
following order: the fuel-side Ar, the Ar shield gas, the
air, and finally the methane. Following each flame sam-
pling, the gas flows are turned off (i.e., the flame is
extinguished) in the reverse order.
A routine problem that has been encountered is a flaring of
the flame immediately after lighting, due to an imbalance
between the total flow rate and the venting flow rate. If the
appropriate adjustments cannot be made quickly, students
are instructed to use the manual shut-off valves to shut off
the methane first, then the air, and then to set the mass flow
controllers to a setpoint of zero flow rate so that a hazardous
situation does not arise upon future start-up. To avoid an
accident, students are instructed to immediately alert the
teaching assistant (who is always present) of any equip-
ment malfunction or unusual sight or sound. They are
also trained in the correct evacuation procedure from the
laboratory should this be necessary.
In spite of all these precautions, the active presence of a
knowledgable and experienced teaching assistant is im-

Figure 3. Visual characteristics of an
opposed flow diffusion flame.
Chemical Engineering Education

Thin Dark Zone

Soot Formation
Stagnation Plane.

perative to the safe operation of this experiment.


The mole fraction profiles for a total of thirty chemical
species, ranging from major components to trace aromatics
and PAH, were determined in experiments that lasted from
four to five hours. This represents the analysis of approxi-
mately ten samples withdrawn from the flame, which is
typically adequate to discern trends in the species mole
fraction profiles. Major components are defined as CH4, Ar,
02, N2, CO, H2, and H20 and were all detected with the TCD
and quantified with calibration standards.

Figure 4 shows the chemical structure and summarizes the
method of quantification for each hydrocarbon product and
by-product species detected in the flame. The species that
were detected with the MSD, with the exception of
vinylacetylene and benzene, were quantified with the ioniza-
tion cross section method.1"0 This method provides mole
fractions that are accurate within a factor of two.'10.'l The
accuracy of the mole fractions of species that were quanti-
fied using calibration standards was estimated to be 15%.

For those species detected with the MSD, data analysis
and calculations were undertaken with the aid of HP























Method of Quantification:
TCD/CS- Thermal Conductivity Detector/Calibration Standard
MSD/CS Mass Selective Detector/Calibration Standard
MSD/ICS Moss Selective Detector/Ionization Cross Section

Figure 4. Hydrocarbon species detected in an opposed flow
methane-air diffusion flame.

Fall 1997

ChemStation software. Prior to the experiment, the follow-
ing information was entered for each species: 1) Retention
time and the masses of parent and fragmentation ions, for
purposes of identification; 2) Calibration abundance or ion-
ization cross section information, in order to determine ab-
solute concentrations. After each MSD run, the software was
used to automatically extract raw data from the ion chromato-
gram and to report the number of moles present of each
species (n,) detected by the MSD. Separation and detec-
tion of all species was achieved in under thirty minutes
for each sample withdrawn from the flame, allowing
students to quickly view their data and take corrective
action if necessary before continuing.

Using a spreadsheet program, students then converted the
raw data from the TCD into ni values. The total number of
moles (nT) injected into the GC was also determined using
the ideal gas law at the sampling conditions. The consistency
of the experimental data was calculated from the expression

Consistency = X 100%

Typical consistency values ranged from 95% to 105%.

Due to the sharp concentration gradients associated with
certain species, additional data points may be required to
define the mole fraction profiles. The need for more
samples is not apparent until the raw data from both the
MSD and TCD has been translated and plotted. The
students may use additional lab periods during the
two-week time frame to reduce the data and possibly
analyze more samples, under the close direction and
supervision of the teaching assistant.

The fluid dynamic strain in the flame as set up by the
opposed flow field was calculated as an illustration of
residence time constraints. The strain rate, K, is defined
e as the axial velocity gradient on the oxidizer side of the
stagnation plane. Mathematically, K is defined as
e dz
where u is velocity and z is displacement along the axis
connecting the centers of the burner ports. Since the above
expression requires knowledge of the actual flow field,
which was not available, the strain rate was calculated
using the following expression that requires only observ-
able quantities:[121

-2ua + uf Pf'
K- L u(-uo)

where L, u,, u,, pf, and po are the distance between the
burner ports, the oxidizer port outlet velocity, the fuel
port outlet velocity, the fuel stream density, and the oxi-
dizer stream density, respectively. With the assumption of
plug flow (ensured by a network of screens) and using the
experimental conditions given earlier, this corresponds to

a computed strain rate of 34 sec' at 298 K. This is a rela-
tively low value when compared to the extinction limit of
CH4, suggesting a high residence time within the flame,
which should lead to the production of measurable quantities
of PAH. The maximum mole fractions of the product species
detected in the flame is presented in Figure 5.

Mole fraction profiles for the major species, together with
the temperature profile, are shown in Figure 6. The tempera-
ture profile shows a maximum temperature of 12000C at a
distance of 6.5 mm from the fuel port. The flame tempera-
ture exhibited a nearly linear variation from each burner port
to the point of maximum temperature, which is in good
agreement with the literature."31
The results for the major species mole fraction profiles
compare well with the work done in previous diffusion flame
studies.113,141 As can be seen in Figure 6, both CH4 and 02
were largely consumed at about 7 mm from the fuel port,
near where the maximum flame temperature was observed.
A significant, yet relatively small, amount of 02 penetration
into the fuel-rich portion of the diffusion flame was noted,
however. The mole fraction of CO increased as the fuel was
consumed and exhibited a peak mole fraction of 0.035 at 6
mm, followed by a decrease with increasing distance from
the fuel port. Hydrogen followed the same trend as CO with

cesses. As can be seen in the figure, benzene was by far the
most abundant of the aromatic species produced, with a peak
concentration of about 77 ppm at 4-5mm. All hydrocarbon
species exhibited a sharp decrease in concentration at 7 to
7.5 mm from the fuel port, corresponding to the transition
from fuel-rich to fuel-lean flame chemistry created by the
competition between gas-phase polymerization and oxida-
tion reactions, respectively.15-7] Some of the PAH detected,
presented in order of abundance, were naphthalene, pyrene,
phenanthrene, and cyclopenta(cd)pyrene. Naphthalene ap-
peared in greater concentration than any of the other PAH,
reaching a maximum level of 7.4 ppm. These results are in
excellent agreement with previous studies'"15 and are consis-
tent with those in premixed flames.111
Future plans involve development of the capability to
simultaneously measure PAH and NO, emissions. This way,
students will be able to readily observe the intimate connec-
tions that exist between flame temperature, overall equiva-
lence ratio, dilution, and NOx and PAH emissions.

The opposed jet diffusion flame provides a convenient
laboratory tool to illustrate fundamental environmental chemi-
cal engineering principles associated with combustion. These
experiments strengthen students' engineering knowledge and
skills, concomitant with exposure to the use of sophisticated

a maximum mole fraction of
0.014 at 5.5 mm. The mole frac-
tions of CO and H2 both exhib-
ited maxima on the fuel-side of,
and near to, the point of maxi-
mum heat release (maximum
flame temperature), consistent
with the transition from fuel-
rich to fuel-lean flame chemis-
try. Carbon dioxide and H20
mole fraction profiles followed
a pattern similar to CO and H2
and exhibited maxima at about
7.0 mm from the fuel port, also
close to the point of maximum
flame temperature. These results
are indicative of the occurrence
of the highly exothermic oxida-
tion reactions, CO + OH = CO2
+ H and H2 + OH = H20 + H.
In Figure 7, the mole fraction
profiles for species ranging from
butadiene to PAH are presented.
These species were selected to
illustrate the wide range of hy-
drocarbon pollutants that can be
formed in combustion pro-



lx0l-3 -

1x10o -

1x10 -5


1x107 -7

S- Complete Combustion Products

0 8
U '

Light Hydrocarbons & VOCs

Polycyclic Aromatic
Hydrocarbons (PAH)

c I W 1 I 11
Q. -- T c c
W 0C
a MR 0

z c

Chemical Species (Molecular Weight)

Figure 5. Maximum mole fractions of product species detected in the experiment.

Chemical Engineering Education

instrumentation and the detailed chemistry innate to com-
bustion systems. To make it a valuable and rewarding expe-
rience for students requires faculty with research interests in
the area of combustion to provide in-house expertise and
future generations of experienced teaching assistants who
are seasoned in the associated theory and experimental and
safety techniques and procedures.
We have demonstrated that a large variety of potentially
toxic by-products are formed in the combustion of simple
hydrocarbon fuels. Of the 26 product species detected, 12
are either explicitly or implicitly listed as "hazardous air
pollutants" in the Clean Air Act Amendments of 1990.[16]
The measurement of a large variety of pollutants made an
impact on the undergraduates who participated in this ex-
periment, as they were able to better appreciate the complex-

1.0x100 1400
I 1300

1.Oxio' a

Soo 1200

1. 010-1 H 1100
0 co, 900

1.0x102 00

O 2 4 6 8 10 12
Distance from Fuel Port (mm)

Figure 6. Mole fraction profiles for major species and
temperature profile (T)800

1.0X10 00

1.0x10 600
1.0x10, 300


Fall 1997
0 2 4 6 8
Distance from Fuel Port (mm)

Figure 7. Mole fraction profiles for select trace species.

Fall 1997

ity and breadth of modem environmental issues.

This experiment was made possible by funds from the
Texaco Foundation. The authors also would like to thank Dr.
Marco J. Castaldi for his valuable contributions. The under-
graduate students who participated in the first-ever labora-
tory course run of this experiment (Fall Quarter, 1995) were
Tadashi Allen, Jennifer Bradford, Vincent Chan, Chung-
Yuan Chiang, Darryl Dunn, Yousun Kim, Ria Momblanco,
Tanya Sacay, Danilo Vukovic, and Tim Wang.

1. Bartok, W., and A.F. Sarofim, Fossil Fuel Combustion, Wiley-
Interscience, NY (1991)
2. Klassen, C.D., M.O. Amdur, and J. Doull, Casarett and
Doull's Toxicology, 2nd ed., Macmillan, NY (1980)
3. Hansell, D.W., G.C. England, N. Soelberg, W.R. Seeker, M.
Lev-on, and S. Folkarkow, Paper given at Air & Waste
Management Association, 85th Annual Meeting, Kansas
City, MO (1992)
4. Clement Associates, Inc., US EPA, Integrated Risk Infor-
mation System (IRIS) (1991)
5. Frenklach, M., and J. Warnatz, "Detailed Modeling of PAH
Profiles in a Sooting Low Pressure Acetylene Flame," Comb.
Sci. Tech., 51, 265 (1987)
6. Miller, J.A., and C.F. Melius, "Kinetic and Thermochemical
Issues in the Formation of Aromatic Compounds in Flames
of Aliphatic Fuels," Combust. Flame, 91, 21 (1992)
7. Glassman, I., Combustion, 2nd ed., Academic Press, NY
8. Puri, I.K., and K. Seshardi, "Extinction of Diffusion Flames
Burning Diluted Methane and Diluted Propane in Diluted
Air," Combust. Flame., 65, 137 (1986)
9. Du, J., and R.L. Axelbaum, "The Effect of Flame Structure
on Soot-Particle Inception in Diffusion Flames," Combust.
Flame, 100, 367 (1995)
10. Fitch, W.L., and A.D. Sauter, "Calculation of Relative Elec-
tron Impact Total Ionization Cross Section for Organic Mol-
ecules," Anal. Chem., 55, 832 (1983)
11. Castaldi, M.J., A.M. Vincitore, and S.M. Senkan, "Micro-
Structures of Premixed Hydrocarbon Flames: Methane,"
Combust. Sci. Tech., 107, 1 (1995)
12. Chelliah, H.K., C.K. Law, T. Ueda, M.D. Smooke, and F.A.
Williams, "An Experimental and Theoretical Investigation
of the Dilution, Pressure and Flow-Field Effects on the
Extinction Condition of Methane-Air-Nitrogen Diffusion
Flames," Twenty-Third Symposium (International) on Com-
bustion, The Combustion Institute, Pittsburgh, PA, 503
13. Zhang, C., A. Atreya, and K. Lee, "Sooting Structure of
Methane Counterflow Diffusion Flames with Preheated Re-
actants and Dilution by Products of Combustion," Twenty-
Fourth Symposium (International) on Combustion, The Com-
bustion Institute, Pittsburgh, PA, 1049 (1992)
14. Smooke, M.D., I.K. Puri, and K. Seshardi, "A Comparison
Between Numerical Calculations and Experimental Mea-
surements of the Structure of a Counterflow Diffusion Flame
Burning Diluted Methane in Diluted Air," Twenty-Fourth
Symposium (International) on Combustion, The Combus-
tion Institute, Pittsburgh, PA, 1049 (1992)
15. Vincitore, A.M., and S.M. Senkan, "Experimental Studies of
the Micro-Structures of Opposed Flow Diffusion Flames:
Methane," Combust. Sci. Tech., in review (1997)
16. The Clean Air Act, 112, as amended, 42 U.S.C. 7412 O




Merging Theory and Practice in

Graduate Education

University of Virginia Charlottesville, VA 22903-2442

Pollution prevention and process integration are highly
consistent concepts in chemical manufacturing. Pol-
lution prevention through source reduction, reuse, and
recycle of resources is stipulated by law."' Process integra-
tion is inherently conservation oriented, as it has the primary
goal of maximizing the efficiency of design by minimizing
the consumption of materials and energy.[2] A chemical pro-
cess in which components are integrated in an efficient sys-
tem will generally be more economical and will pollute less.
Ultimately, our goal in chemical process design should be
closed-loop systems with zero emission to the environment,
but this goal, of course, has to be balanced against economic
factors and other constraints that would normally be encoun-
tered in practical situations. This can only come about through
the education and training of scientists and engineers who
can implement technological advances in designs that inte-
grate regulatory and environmental considerations with the
goal of economic development within the constraints of an
industrial operation.
A new course, "Process Integration and Industrial Pollu-
tion Prevention," was recently developed at the University
of Virginia with the assistance of several experts and with
the participation of a company sponsor. The course is of-
fered within the university's Environmentally Conscious
Chemical Manufacturing (ECCM) Program (supported by a
Graduate Research Training grant from the National Science
Foundation and by a grant from the Academic Enhancement
Program of the University of Virginia), which has both
research and educational components. Fundamental research

I Dept. of Chem. Engineering, Vanderbilt Univ., Nashville, TN
2 Matrix Process Integration, Inc., Leesburg, VA
3AlliedSignal, Inc., Hopewell, VA
4 Mays & Valentine, L.L.P., Richmond, VA

is conducted in four major areas: development of inorganic
catalysts; development of biocatalysts for chemical synthe-
sis; development of alternative solvents; and development of
adsorption processes for separations and energy applica-
tions. In each area the goal is to provide a foundation for the
conception and development of alternative, environmentally
benign technologies.
This graduate course in pollution prevention provides a
central focus for both the students and the faculty participat-
Giorgio Carta is Professor of Chemical Engineering at the University of
Virginia. He received his MChE and PhD degrees from the University of
Delaware and his Laurea in chemical engineering from the University of
Cagliari (Italy). He currently serves as coordinator of the University of
Virginia Environmentally Conscious Chemical Manufacturing program.
His research interests are in separations and biochemical engineering.
M. Douglas Le Van is Centennial Professor and Chair of the Department
of Chemical Engineering at Vanderbilt University. He received his BS
degree from the University of Virginia and his PhD from the University of
California, Berkeley. He has been Senior Research Engineer for Amoco
Production Company and was on the faculty of the University of Virginia
for nineteen years. His principal area of research is adsorption.
H. Dennis Spriggs is President of Matrix Process Integration, a consult-
ing firm specializing in integrated process designs, developing operating
strategies, and aligning technology with corporate strategy. He has over
thirty years of industrial and academic experience, including AlliedSignal
and Union Carbide Corporation, and has operated his own business
since 1985. He received his BS degree from West Virginia Institute of
Technology and his PhD from the University of Virginia. He is on the
advisory board of the ECCM program at the University of Virginia.
Gregory A. Cleotells, II, is Senior Process Engineer at AlliedSignal,
Inc., in Hopewell, Virginia. He received his BS degree in chemical
engineering from the University of Virginia and has over fifteen years of
industrial experience as a process engineer.
James E. Ryan, Jr., is a partner with Mays & Valentine, L.L.P., in
Richmond, Virginia, where he practices environmental law, specializing
in corporate environmental audit programs, industrial development, and
municipal water projects. Previously, he served as Deputy Attorney
General of Virginia. He received his BS degree in chemical engineering
from the University of Virginia and his JD degree from the Catholic
University of America.
Copyright ChE Division ofASEE 1997
Chemical Engineering Education

Ultimately, our goal in chemical process design should be closed-loop systems with zero emission to
the environment, but this goal, of course, has to be balanced against economic factors and other
constraints .... This can only come about through the education and training of scientists and
engineers who can implement technological advances in designs that integrate regulatory
and environmental considerations with the goal of economic development....

ing in the program. It seeks to
provide an opportunity for inte-
grating technological develop-
ments within the framework of
real industrial constraints. Thus,
a major component of the course
is a project carried out in col-
laboration with an industrial
partner. In addition, the course
exposes the students to legal and
regulatory issues, integrated de-
sign methodologies, hierarchi-
cal strategies for pollution pre-
vention, and computational tools
for waste minimization.
As a whole, the course is an
example of a new approach to
graduate education in chemical
engineering. It provides an en-

Building blocks: Principles, Unit Operations

How to Assemble: Philosophy (SOTBP)
Tools (Integrated methodology)
Application (Design experience)

Figure 1. The focus of this course: how to
integrate building blocks into integrated
process design.

vironment where students can learn while simultaneously
solving significant industrial problems. This, of course, is
always done through the research component of doctoral
studies, and that must continue to be the main focus. On the
other hand, doctoral research is typically long-term, funda-
mental work, often remote from industrial applications and
almost always conducted in ways quite different from those
used in industry for the solution of plant problems. In an
industrial setting, short time frames, teamwork, and integra-
tion of economic considerations are often dominant issues
that are not considered within the typical doctoral research
activities. An approach where graduate students are im-
mersed for a time within a practical setting is common in
many professional graduate schools, such as business,
law, and medicine, but is not often found in chemical
engineering. This field, however, could also benefit tre-
mendously from such exposure in ways that could pro-
vide avenues for successful partnerships between indus-
try and academia.

The fundamental premise for this course is shown in Fig-
ure 1. An efficient, nonpolluting chemical process is based
on technological innovations that are rationally integrated in
a system. The "building blocks" (fundamental principles and
unit operations) come from research; the "how to assemble"

Fall 1997

know-how and tools are covered in
the course.
There are three main themes:
1. The philosophy of integrated de-
2. The tools for an integrated design
3. The application to an actual in-
dustrial situation
The underlying philosophy taught
in this course is what has been called
the "Science of the Big Picture," or
SOTBP, as a simple heuristics set for
design that entails the following
Consider the "big picture first" by
looking at the global process as an
integrated system

Use fundamentals at each step to establish a priori targets for
design efficiency and the consumption of materials and
Worry about details (later) to finalize the design and support
the global view.

The term "fundamentals" here denotes thermodynamics
laws and basic mass and energy balances. Virtually all estab-
lished integrated design methodologies, such as thermal pinch
analysis[4'51 and mass exchange networks,16'71 follow this gen-
eral heuristics set. Following this approach, process design
evolves through a series of decisions that provides increas-
ing levels of detail. Each decision will be sound from the
overall viewpoint and will be consistent with fundamentals.
Details are worked out later, only after the overall structure
of the process has been established. Thus, a global under-
standing of the process is obtained first. Next, methods of
structured thinking, including how to decompose the design
problem and to apply rules-of-thumb and experience, are
used. And finally, simulations and/or experimental analyses
are used in support of fundamental understanding and to
complete design details.
The tools reviewed in the course are methodologies for
integrated design. The hierarchical review methods of Dou-
glas and others[2'8-101 are covered in detail and contrasted to
traditional approaches that break down a process into its unit

operation components instead of levels of analysis. The point
is made that while breaking the system down into units has
been a traditional way of dealing with complex processes, it
provides little information about the interconnection of the
elements and sheds no light on how these elements should
come together to form an efficient process. Techniques for
heat and mass integration are also reviewed with an empha-
sis on visualization techniques as a key to understand the
problem, generating solutions, and communicating. Le-
gal and regulatory issues are also covered and are viewed
as an integral part of the "big picture" of the pollution
prevention problem.
Finally, the application component of the course is an
actual industrial project that is developed as an assignment
for the students in collaboration with an industrial sponsor.
The students are given free rein to solve the problem at hand
using any of the tools available and including experimenta-
tion. The project has to be conducted within the framework
imposed by the industrial sponsor, however.

The course was team-taught and involved the participation
of several experts. Approximately half of the class time was
in a lecture format, while the remaining time was spent
working on the course project (see Table 1). In the first
offering, eleven doctoral students took the class. They
were divided into two design teams, each with an ap-
pointed team leader. Regular meetings were scheduled
with the course instructors.
The course began with an overview of the driving forces at
the root of pollution prevention in industry (environmental
regulation, product quality and consumer demand, and effi-
ciency and cost reduction), of the industrial obstacles to its
implementation (unfavorable balance between long-term en-
vironmental benefit and short-term profit, capital require-
ments, inertia), and of regulatory impediments to pollution
prevention (complexity and inconsistency of environmental
regulation, regulatory focus on individual media, narrow
definitions of pollution prevention).
Next was a detailed coverage of the legal principles of
environmental regulation and of regulatory aspects of man-
agement strategies for achieving pollution prevention. Four
lecture hours given by two practicing environmental lawyers
covered the history of modern environmental law, the rela-
tionship between federal and state government in the envi-
ronmental arena, and the common elements of statutory
programs such as ambient and performance standards, per-
mit programs, self-reporting requirements, and enforcement
tools. The structure of Virginia's environmental programs
(water and air) was also covered as an example.1" These
lectures included an overview of the Pollution Prevention
act of 1990 and of ISO 14000 and 14001 standards.[121

The next set of lectures introduced a general framework
for pollution prevention through integrated design."13 We
began by defining design as a multifaceted problem that
depends on both "technical" and "nontechnical" factors, in-
cluding the overall business environment the company oper-
ates in, how the design work is organized, and the impor-
tance the company places on process design. The key point
illustrated here was that pollution prevention is not just a
"technical" problem. And, it is not just a matter of manage-
ment. It is both-which makes it especially challenging.
Considerable emphasis was then placed on correctly struc-
turing "the problem." The instructors' experience is that
engineers, even experienced ones, must be helped to see the
big picture first and to fill in the details later. It is a
process that must begin with a clear definition and set-
ting of goals: the sponsor's goals, the goals of the indi-
vidual participants, and the time-frame within which these
goals are to be attained.
The students were challenged to define their own personal
goals in this class, pointing out that the ultimate measure of

Course Syllabus
Week Topic
1 Introduction; course outline, driving forces, and impediments to
pollution prevention
2 Legal principles of environmental regulation; management
strategies for pollution prevention
3 Process integration for pollution prevention-fundamentals
4 Introduction of course project
4-5 Hierarchical review of chemical processes for pollution
5-7 Heat and mass integration-HEN's and MEN's
8 Waste assessment and pollution prevention measures
9-14 Course project, team meetings, interaction with sponsor, and



Figure 2. Global view of a chemical process as a closed
system with integrated mass and energyflows.11

Chemical Engineering Education

success might be the actual implementation of the solution
proposed for the course project. We made the point that just
arriving at a solution is not sufficient-getting the sponsor to
appreciate its value and to implement it is part of the job.
Thus, we emphasized the need for effective contact with the
sponsor as a key to credible, implementable solutions.
The next set of two lectures was devoted to a presenta-
tion of the course project (described later). Two process
engineers from the sponsoring company presented the
situation defining the problem, the technical company
constraints, and the expectations.
Following this introductory material, a set of lectures was
devoted to a review of process integration tools. Students
were challenged to view chemical processes as integrated
systems such as the one depicted in Figure 2. Our job is to
find the most favorable allocation of mass and energy flows

I Mass-Separating
------ Agentsin RinkL/ Sources

Mass-Separating Agents out
(to Regeneration and Recycle)
Figure 3. Mass allocation network with segregation,
interception, and recycling'

Off gases


Bleed stream
(Water, Cu, V,
nitric acid,
organic acids)

Figure 4. Simplified process flow diagram for adipic acid
manufacturing process used as course project.

Adipic acid

that would minimize waste. The first step in the analysis is a
hierarchical review of design decisions at different levels of
detail. Following Douglas' work,8'91 we made the point that
this procedure, originally developed for process synthesis,
can also be applied for waste minimization in an existing
facility, as discussed, for example, by Rossiter, et al.1'01 In
fact, by understanding how waste is generated from deci-
sions made at different structural levels, one can systemati-
cally develop retrofit alternatives.
Beyond the hierarchical review approach, two important
dimensions of the problem were considered in detail: the
creation and routing of chemical species (mass integration or
mass exchange networks-MEN's) and the application of
energy (energy integration, or HEN's). In heat integration
we examined tools such as pinch analysis (or pinch technol-
ogy),14'5 mixed-integer nonlinear programming, and simu-
lated annealing[l"4 that shift the focus away from the heating
and cooling of individual streams to the global allocation of
energy in an integrated system. Similarly, in mass integra-
tion, we examined recently developed techniquesl67 that shift
the focus away from merely linking unit operations (reactors
and separation units) to a global allocation of chemical spe-
cies by considering the efficient creation of desirable spe-
cies, the minimization of undesirable components, and
the routing of species to their most desirable destina-
tions. A recent monograph by El-Halwagi~"51 provided
reference material and case studies in mass integration.
Figure 3 shows the generic approach for species alloca-
tion presented in this work.
When the overall process is considered, waste minimiza-
tion targets can be established a prior based on fundamental
application of overall balances. This is true for both
energy and mass integration. A species allocation dia-
gram similar to that in Figure 3 is drawn for each
chemical species (e.g., water in a waste-water minimi-
zation problem). The first step is then to consider
ter segregating each "source" or stream containing that
species. Often, major waste reduction can be obtained
simply by avoiding mixing of process streams and
reusing the segregated sources with a direct recycle to
ter the process.

The next step is to consider implementation of a
"species interception network" (SPIN) where mass-
separating agents are used to upgrade segregated
sources to a quality adequate for in-process recycle to
appropriate "sinks"-ordinarily unit operations that
can use the upgraded sources. Shortcut design meth-
ods are used for screening alternatives at this level on
the basis of cost estimates and economic potential.
Finally, the last step is to consider manipulation of
"sinks" and "generators" so as to reduce the creation
of undesirable species and improve their efficiency.

Fall 1997

Clearly, a hierarchical level exists in this analysis. Usu-
ally, acceptability (and, in many cases, impact) is great-
est for simple segregation and direct recycle modifica-
tions of an existing process while acceptability, and some-
times impact, is normally smallest for more costly sink/
generator manipulations.
In a final set of lectures, we covered quantitative aspects
of pollution monitoring and emission inventory[16] and ex-
amples of pollution prevention measures based on the
work of Nelson.[17] The rest of the semester was spent
working on the course project in close collaboration with
the industrial sponsor.

The project for this course was suggested by AlliedSignal
personnel. It deals with an existing problem concerning cop-
per emissions from an adipic acid manufacturing plant. At a
facility in Virginia, AlliedSignal produces about 30 Mlb/yr
of adipic acid via the oxidation of a waste stream composed
of cyclohexanol and cyclohexanone, which is generated in
another process. Figure 4 shows a simplified process flow
diagram. The process produces 3,000 to 5,000 lb/h of crys-
talline adipic acid as well as a bleed stream at a rate of about
2,000 to 3,000 lb/hr that contains water, nitric acid, organic
acids by-products (principally glutaric and succinic), as
well as copper and vanadium, which are catalysts for the
oxidation process. Currently, the bleed stream is neutral-
ized and sent to a regional waste-water treatment plant.
The company anticipates that changing waste-water regu-
lations will require the virtual elimination of copper dis-
charges. The following objectives were thus set by the
1. Recover copper and vanadium from the bleed stream
2. Recover nitric acid from the bleed stream and recycle to the
3. Recover the organic acids from the bleed stream

The sponsor specified that the first objective must be ac-
complished. Objectives 2 and 3 were to be pursued if eco-
nomically feasible. The sponsor required that the solution
should be implementable in an 18-month time frame and
that a 35% simple rate of return should be used for economic
evaluation. The short time frame precluded most solutions
involving changes in the process chemistry that would entail
major modifications of the existing adipic acid facility.
The eleven PhD students enrolled in the class were di-
vided into two independent teams that engaged in a friendly
competition. Each team conducted its own literature search,
visited the plant on several occasions, obtained samples of
the bleed stream and other data from the plant, conducted
their own experimental investigation, and carried out pre-
liminary design calculations and economic estimates. An
initial proposal was to install end-of-pipe treatment devices

(ion-exchange columns, membrane systems, electrochemi-
cal methods, etc.) that would remove copper from the bleed
stream. When the process was analyzed from a global view-
point, however, these alternatives were quickly discarded
since it was recognized that it would be sufficient to recover
the organic acids in order to produce an aqueous stream
containing copper and vanadium catalysts and nitric acid
that could be recycled directly to the process. This required
the definition of a waste interception network capable of
removing the approximately 400 to 800 lb/hr of glutaric and
succinic acid that is produced as a by-product in the oxida-
tion process.
The teams recommended different solutions. One team
followed a more traditional approach of esterifying the acids
with an excess of methanol and extracting the diesters with
an organic solvent. The students initially followed a US
patentf'81 describing a reactive-extraction process, but then
decided to perform their own experimental investigation
finding that no-catalyst was required for esterification in the
bleed stream and that toluene could be used as an effective
extraction solvent. The other team followed a more inno-
vative approach, discovering in the laboratory that, for
the conditions of the bleed stream, the organic acids
could be extracted into an existing process feedstock.
Although the partition coefficient is not as favorable as
in the case of extraction of the dimethylesters, the pro-
posed approach has the advantage that the extraction
solvent is a reactant in the process so that no contamina-
tion of the existing adipic acid facility with extraneous
species would occur. The raffinate, devoid of a large
portion of the organic acid by-products, could be re-
cycled directly to the adipic acid process.
Based on preliminary design and economic estimates, each
alternative met the sponsor's objectives. In each case, in
addition to virtually eliminating copper emissions, potential
sales of the recovered organic acids would provide a sub-
stantial economic return. At the conclusion of their work,
each team presented their recommendations to the spon-
sor. This task was made rather challenging by the fact
that the presentations took place at the plant and were
attended by a large group that included senior plant man-
agement, several process engineers, plant operators, en-
vironmental officers, and chemists and engineers from
the technical support group of the company. The students
were asked to meet this challenge with a balanced pre-
sentation addressing the diverse audience. The company
is now evaluating implementation of one of the two pro-
posals made by the students and is acquiring equipment
for pilot-scale testing.
Finally, it should be noted that although the project scope
was limited by the sponsor to water emissions, a broader-
scope project could be developed by considering air emis-
sions as well.

Chemical Engineering Education

This course was an invaluable experience for both the
students and the faculty. It provided the students with an
opportunity to do something that is rare in graduate educa-
tion, but common in industrial practice-the opportunity to
work in teams on the solution of a real problem from the
basics to virtually its implementation. The students who
took this course are involved in doctoral research in ex-
tremely diverse areas, from catalysis to biochemical engi-
neering to separations. Thus, each student brought particular
skills to the completion of the project. Through the team's
efforts, each student learned to treat real problems from a
global perspective within defined constraints. One of the
main lessons was that optimum solutions to environmental
problems often come from an intelligent reengineering of
the process itself, rather than through the adoption of end-of-
pipe approaches.
The course was geared for doctoral candidates and most of
the students were at an advanced level. Although a different
version of such a course could be developed for all graduate
students, the time commitment required for a successful
interaction with industry could be difficult to meet by begin-
ning graduate students who are engaged in other coursework.
A key to the success of this course was the commitment of
the sponsor to the effort. The company sponsor shared valu-
able data and experience with the students and provided
guidance at a level that the faculty alone could not have
provided. Likewise, external experts who participated both
in the conception and in the offering of this course provided
a different and unique perspective that added tremendous
value to the educational experience.
Finally, there was a "real" value in return to the company
sponsor. Aside from the direct technical contributions, com-
pany personnel were exposed to a way of thinking about
chemical processes that is different from traditional, unit-
operations-based approaches. Essential to this success was
the sense of trust and respect that developed among the
participants through frequent interactions at different levels.
This course provided several opportunities for the devel-
opment of instructional modules for use in our undergradu-
ate design class. One of the modules is focused on legal and
regulatory aspects, with emphasis on pollution prevention.
The other is a design project based on the data obtained by
the graduate students and their proposals for the solution of
the copper emission problem. The latter was offered as a
senior undergraduate design project. The undergraduates who
took the project enjoyed working on a real problem using
data developed "in house" as the basis for their design calcu-
lations and learned a great deal by working within the con-
straints of an actual industrial situation. A version of this
project including technical specifications and economic data
is available upon request.

Fall 1997

Development of this course was supported by a grant from
the Academic Enhancement Program of the University of
Virginia. We are indebted to Stan Sitnik of AlliedSignal,
Inc., and to Wayne Halbleib of Mays & Valentine for their
participation in the course. Support from the National Sci-
ence Foundation Graduate Research Traineeship program is
also gratefully acknowledged.

1. Garrison, G.W., H.D. Spriggs, A.H. Hanad, and M.M. El-
Halwagi, "An Integrated Approach to Cost and Energy Effi-
cient Pollution Prevention," Fifth World Congress of Chemi-
cal Engineering, San Diego, CA, July (1996)
2. Doerr, W.W., "Plan for the Future with Pollution Preven-
tion," Chem. Eng. Progr., p. 24, January (1993)
3. Buehner, F.W., and A.P. Rossiter, "Minimize Waste by Man-
aging Process Design," CHEMTECH, p. 64, April (1996)
4. Linnhoff, B., D.W. Townsend, D. Boland, G.F. Hewitt, B.E.A.
Thomas, A.R. Guy, and R.W. Marsland, User Guide on
Process Integration for the Efficient Use of Energy, Institute
for Chemical Engineering, Rugby, UK (1982)
5. Linnhoff, B., "Pinch Analysis-A State-of-the-Art Overview,"
Trans. IChemE, 71, 503 (1993)
6. El-Halwagi, M.M., and V. Manousiouthakis, "Synthesis of
Mass Exchange Networks,"AIChE J., 35, 1233 (1989)
7. El-Halwagi, M.M., and B.K. Srinivas, "Synthesis of Reac-
tive Mass-Exchange Networks," Chem. Eng. Sci., 47, 2183
8. Douglas, J.M., Conceptual Process Design, McGraw-Hill,
New York, NY (1988)
9. Douglas, J.M., "Process Synthesis for Waste Minimization,"
Ind. Eng. Chem. Research, 31, 238 (1992)
10. Rossiter, A.P., H.D. Spriggs, and H. Klee, Jr., "Apply Pro-
cess Integration to Waste Minimization," Chem. Eng. Progr.,
p. 30, January (1993)
11. Ryan Jr., J.E., et al., Virginia Environmental Law Hand-
book-Mays & Valentine, 2nd ed., Government Institute,
Inc., Rockville, MD (1992)
12. ISO 14001: Environmental Management Systems Specifica-
tions with Guidance for Use, International Organization for
Standards, Geneva, Switzerland (1996)
13. Spriggs, H.D., "Design for Pollution Prevention," in Pollu-
tion Prevention via Process and Product Modifications, M.M.
El-Halwagi and D.P. Petrides, eds., AIChE Symp. Ser., 90,
American Institute of Chemical Engineering, New York,
NY (1995)
14. Dolan, W.B., P.T. Cummings, and M.D. LeVan, "Process
Optimization via Simulated Annealing: Application to Net-
work Design," AIChE J., 35, 725 (1989)
15. El-Halwagi, M.M., Pollution Prevention Through Process
Integration-Systematic Design Tools, Academic Press, New
York, NY (1997)
16. Allen, D.T., and K.S. Rosselot, Pollution Prevention for
Chemical Processes:A Handbook with Solved Problems from
the Refining and Chemical Processing Industries, Hazard-
ous Waste Research and Information Center, Champaign,
IL (1994)
17. Nelson, K.E., "Use These Ideas to Cut Waste," Hydroc.
Proc., 69, 93 (1990)
18. Hatten, J.L., K.R. Nauck, Jr., and S.S. Mims, U.S. Patent
No 3,726,888 (1973) D



... Another Successful Session at the

ne activity that serves to nurture learning and to Chicago AlChE Meeting
instill pride and a sense of community within our
engineering profession is introducing students to the
authors of their textbooks, and at two of the recent AIChE
national meetings, Phil Wankat and Don Woods organized a
session to do just that. In the session, featured authors were
invited to present the "inside story" about their textbook, and
then students were given a chance to mingle and to seek
autographs and photographs. Other authors who were present
in the audience were also introduced, and they too became
focal points for the students.
At the Chicago meeting, the featured authors were Christie
Geankopolis, author of Transport Processes and Unit Opera-
tions, and Ron Rousseau, coauthor with Rich Felder of El-
ementary Principles of Chemical Processes. Other authors
who were present and were introduced to the students in-
cluded Klaus Timmerhaus, coauthor with Max Peters of Plant Featured author, Christie Geankoplis, poses with stu-
Design and Economics for Chemical Engineers and Scott dents from the University of Alabama. From left to right:
Fogler, author of Elements of Chemical Reaction Engineer- Vikram Gopal, Armando Esponal, Marie Baker, Jason
ing. Ryder (President of the SIChE student section), author
Christie Geankopolis, Daphne Robertson, Chris Goryle,
The photographs do not do justice to the enthusiasm gener- and Elisa Currins. (Photo by courtesy of Barrett Steele)
ated in the session.

Students are clustered around authors
(left to right) Klaus Timmerhaus,
Christie Geankoplis, Ron Rousseau,
Phil Wankat, and Scott Fogler. (Photo
by courtesy of Daphne Robertson.)

Photos below: One student's lucky
day times three. Barrett Steele
poses with (left to right) Ron
Rousseau, Klaus Timmerhaus, and
Christie Geankoplis. (Photos by
courtesy of Barrett Steele.) V V

Chemical Engineering Education


re^ book review

Movement of Chemicals in Air, Water, and Soil, 2nd edn.
by Louis J. Thibodeaux
Published by John Wiley & Sons, New York, NY; 593 pages,
$69.95 (1996)

Reviewed by
T. R. Marrero
University of Missouri-Columbia

Quality, quality! The Second Edition of Environmental
Chemodynamics is a revised and updated version of the
1979 edition that is an outstanding contribution to chemical
engineering textbooks for senior and graduate students. Be-
cause of its logical organization, completeness, and exten-
sive index (23 pages), it is quite useful to the practicing
engineer who has to review the concepts and calculation
techniques of chemical equilibrium and transport processes
relevant to the fate and rate of movement of chemicals
across air-water, water-soil, soil-air interfaces.
This second edition has many figures (146) and tables (86)
with useful illustrations of basic engineering principles and
environmental data, plus 34 examples. Each chapter has
many references, a majority from primary sources; a total of
369 references are cited. It includes 161 problems (50%
more than the first edition), and most of them are practical.
A solutions manual is available.
In two chapters, Environmental Chemodynamics presents
clear and succinct descriptions of chemical engineering prin-
ciples pertinent to the movement of chemicals in the environ-
ment. Three chapters describe the concepts, quantification tech-
niques, and reliability of predictions for the interphase move-
ment of chemicals. One chapter covers the basics of intraphase
(air, water, and subterranean media) mass transfer.
The purpose of Environmental Chemodynamics is to teach,
at a university level, the chemical engineering equilibrium
and transport (heat, mass, and momentum) methods appli-
cable to situations involving the movement of chemicals in
the natural environment.
The author, Louis Thibodeaux, is the Jesse Coates Profes-
sor of Chemical Engineering at Louisiana State University.
He is nationally and internationally known for his outstand-
ing research and teaching in the area of environmental sci-
ence and engineering. His activities in this area have tran-
spired for more than twenty-five years.
A student must first become familiar with the systemic
and mnemonic notation used in the text. This neat informa-
tion is presented in chapter one and allows the specification
of controlling factors for different environmental systems.
Chapter one includes the definition of "trace" constituents
Fall 1997

that are important to environmental analyses and a classic
example of mass transfer, the re-aeration of natural streams.
This example is almost essential for chemical engineering
students who have never considered quantitative problems
outside of chemical process systems. The reader of chapter
one also learns that the law of conservation of mass was first
experimentally established by Antoine Lavoisier in 1777.
Chemical engineering basic principles of thermodynamics
and transport phenomena are well covered in chapters two
and three, respectively. These two chapters teach fundamen-
tals required for the problems presented in the four subse-
quent chapters. Topics include chemical and thermal equi-
librium at environmental interfaces, diffusion, mass transfer,
and turbulence. The understanding of these concepts and phe-
nomena for the prediction of chemical movement in the envi-
ronment is essential to the environmental engineer and comple-
ments earlier classroom studies by chemical engineering stu-
dents. Fundamentals are clearly explained in this book.
The final four chapters are the "meat" of Environmental
Chemodynamics. The major topics are: Chemical Exchange
Between Air and Water (Chapter 4); Chemical Exchange
Between Water and Adjoining Earthen Material (Chapter 5);
Chemical Exchange Between Air and Soil (Chapter 6); and
Intraphase Chemical Transport and Fate (Chapter 7).
Each major topic is divided into subtopics that define the
applicable terms, illustrate the concepts and systems, and
provide examples and problems from actual events and re-
search studies. The text is not esoteric. Figures illustrate the
concepts and explicitly specify the systems of interest. Data
in table form are immediately available to the students; these
environmental data are not readily found in other chemical
engineering textbooks or handbooks. Chapter four well ex-
plains a method to calculate the desorption (absorption) of
gases from aerated basins and rivers. Chapter five empha-
sizes the determination of chemical movement at the bottom
of quiescent water bodies (ponds, lakes) and flowing streams.
Chapter six divides the chemical movement across the air-
soil interface into two regions: through the lower layer of the
atmosphere and through the upper layer of earthen material.
The last chapter presents mathematical models for chemical
movement in surface water and well-known methods of
mass transport in the lower atmosphere.
In conclusion, this reviewer's opinion is that Environmen-
tal Chemodynamics is an excellent resource for practicing
engineers as well as the best textbook available for the
teaching the fate and transport of chemicals in the environ-
ment. The editors of the Wiley-Interscience Series in Envi-
ronmental Science and Technology are to be commended for
including this text in their series on Environmental Science
and Technology. O

class and home problems

The object of this column is to enhance our readers' collections of interesting and novel
problems 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 which
elucidate difficult concepts. Please submit them to Professor James O. Wilkes (e-mail: or Mark A. Burns (e-mail:, Chemical
Engineering Department, University of Michigan, Ann Arbor, MI 48109-2136.



Mathematical Modeling

King Saud University Riyadh 11421, Saudi Arabia

One important feature of the CSTR is its operation
under steady-state conditions. It shows, however,
transient behavior during start-up and shut-down
periods of operation, although these periods are relatively
short compared to those in steady-state operation. Modeling
of these transient periods can be of great value since, during
their operation, they affect product quality. Care must be
given to the operating conditions involved and the proce-
dures followed in start-up and shut-down.

Consider a CSTR with an overflow outlet.1' Solutions of
reactants A and B, of equimolar concentrations and at the
same feed temperature, are fed at equal flow rates into the
reactor. The order of the reaction is known, and the rate
constant is a function of temperature. The .following are
three possible approaches for starting up the reactor:
I Add both reactants simultaneously into the empty
II Start with a certain volume of reactant A, then add
both reactants simultaneously.
III Fill the reactor with A, then add both reactants
Our objective is to model these different types of start-up
mathematically under non-isothermal conditions and to de-
velop differential equations (on the basis of material and
Copyright ChE Division ofASEE 1997

Aziz M. Abu-Khalaf is a member of the chemi-
cal engineering teaching staff at King Saud
University. His main interests are in mathemati-
cal modeling, corrosion, and controlled-release

energy balances) that describe the dynamics of this CSTR,
and then solve them numerically.
Note that in start-up methods I and II, the reactor passes
through three stages: it fills up, it approaches steady state,
and then it operates steadily. In type III, the reactor passes
through only the last two states, because it is already full.
1. Negligible variations of heat capacity and heat of
reaction with temperature
2. Negligible non-idealities of solutions (which are
3. No change in volume due to mixing or reaction
4. Constant density
5. No side reactions
6. Since we have a liquid mixture under atmospheric
pressure, we can safely equate the internal energy to
the enthalpy of the system.
7. Resistance to heat transfer inside the reactor and
through its walls, and the shaft work due to mixing,
are negligible.

Chemical Engineering Education

Start-Up: Type I
During Stage 1 of this start-up type, the reactor is filling
up with no output, while the reaction still occurs. Concentra-
tion, volume, and temperature are all changing with time. In
Stage 2, the reactor overflows (reacting volume becomes
constant), but concentration and temperature will change
until Stage 3 is reached, in which steady state prevails.
Stage 1.
A mass balance on component i gives

(VC,)= FCf +Voir (1
The volume is a variable, so a total mass balance is needed,
giving (consider assumption 5)

and, since the reactor is initially empty,

By expanding the left-hand side of Eq. (1) and using Eqs.
(2a) and (2b), we obtain
dCi Cif -Ci
-d +air (3)
dt t
which is subject to the initial condition that as t -> 0+, C, = Cif.
An energy balance gives (consider assumptions 2 and 6)

d[ Ci] = Fy Cif f Q* (4)
in which I sums all the components involved. After some
manipulations and using Eqs. (1), (2a), and (2b), Eq. (4)

CidI'= I Cif(HiI-Hi)-ryiHI (5)
t CFt (5)
dt t Ft
in which the second term on the right-hand side is the heat of
reaction at the temperature of the system. Choosing the inlet
temperature as a reference and considering assumption 1,
Eq. (5) becomes
dT(TT Q*
(cc) (ci) -rAH-Ft (6)
in which AIHi is the standard heat of reaction. The heat loss
term, Q*, is related to the surface area of the system, S, and
the temperature difference as follows:
Q* =Shair(T- Tab)= hair(T-Tamb) (7)
After substituting Eq. (7), Eq. (6) becomes
V dT ( T-Tf) rAH 4hair (8)
i dt piif t D (T-amb) (8

subject to the condition that as t -> 0, T= Tf.
Stage 2.
A mass balance gives
dC FCif FCi + Vir (9
where r = t- 0 and = V/ F. Thus, the zero time for this
Fall 1997

stage is at t= 0. An energy balance gives the following
equation (considering assumption 7):

[VYCiH] = FECfiff- FCiHi -Q* (10)
By expanding the left-hand side of Eq. (10), substituting
Eq. (7) and Eq. (9) and using the definition of the heat of
reaction and noting assumption 1, we get, after taking as a
reference the inlet temperature,

c iCi ) dT -' c piCif )(TT)-rA0 -L(T-Tamb )(11)

) subject to the condition that at = 0, T=T,, where T, is the
temperature at the end of stage 1.
Stage 3.
Here, modeling can be approached via direct mass and
energy balances or by simplifying Eqs. (9) and (11), where
the differential terms vanish. In either case, we have

Cis = Cif +eoir

( cp,Ci)(T T,) rAH- (T Tamb)= 0

Start-Up Type II
Stage 1.
The system again passes through three stages, as in Type I,
but we start with a known volume V, of one of the reactants.
The governing equations of Stage 1 of this start-up type are

V = Ft + V,
dCi Cif Ci
d t+(VI/F) +ir
dt t+(V,/F)

with the condition that at t = 0, ci = Cio, and

T^ 4 hair
pic dt piif t + (V / F D (T Tamb

with the condition that T = To at t = 0.
Stage 2.
Here, we have the same equations as in Stage 2 of Type I
(that is, Eqs. 9 and 11), with the difference that T = t -i,
where e1=(V-V,)/F.
Stage 3.
Equations (12) and (13) of Stage 3 in Type I also apply to
Stage 3 of Type II.

Start-Up Type III
Since the reactor is initially full, it now passes through
only two stages, i.e., there is no filling-up stage. Again, Eqs.
(9) and (11) apply to Stage 1 of Type III, with the initial
S conditions that at t = 0, C = Cio, and that T=To. For Stage 2,
Eqs. (12) and (13) are applicable.

Due to the coupling between temperature and concentra-
tion, we need to solve the models simultaneously using
numerical techniques. In order to start the numerical solu-
tion of Eqs. (3) and (8), we must take the limit of these
equations as t approaches zero, giving, for Eq. (3),

dC| 11
dCi =- oiro (17)
dt t=0 2

while for Eq. (8),
dT roAHr 1
dT A AXc 1,(18)
dt t-0 2 icpiCio

Since our system is dilute, integration problems will not
be serious, and any suitable package that handles initial-
value problems can be used (e.g., IVPRK from IMSL). The
models of start-up Type I are very stiff and numerical inte-
gration will proceed well as long as the system is dilute;
otherwise, special techniques or subroutines must be used.
Stiff ordinary differential equations are characterized by
having widely separated eigenvalues, and special attention
to the stability of the numerical technique is required.
Steady-state models are algebraic in nature and have to be
solved simultaneously. The package NEQNF from IMSL
was used here to solve these models.
Our numerical illustration is based on a second-order
reactionl2-41 between sodium hydroxide (A) and ethyl ac-
etate (B) solutions. The products are ethyl alcohol and so-
dium acetate. All stochiometric coefficients are 1 or -1. The
rate of reaction is given as r = kCACB, and the rate constant
as k = 10931 exp(-48.32 / RT), where T is in K and R is the gas
constant. Other conditions are: Cf = 0.1 M for reactants and
zero for products, and the same for initial concentrations;
F = 0.5 1/min; T, = 24 C; Tamb = 29 'C; V = 2.8 1; V, = 1.5 1;
hai, = 2.5 J/m2 C min; and AH = -1.5 kJ/mol. The heat
capacities for the reactants are 75.25 and 175.3, and for the
products are 78.2 and 103.8 J/mol C. The reactor is cylin-
drical with a diameter of 15 cm.

Three methods of start-up were considered (I, II, and III),
with corresponding concentration profiles shown in Figures
1, 2, and 3, respectively. Each component of this system has
a stoichiometric coefficient of 1 or -1, and the feed streams
do not contain any product. During Type I, the rate of
reaction terms takes the form r = kC since both reactants
A and B are of equimolar concentrations. Hence, the pro-
files in Figure 1 are denoted by products and reactants
without reference to any specific component. For other
types, the form of the reaction rate is r = kCACB, since
the concentration of B in these types is initially zero,
and the reactor is initially loaded with A. Component B
has a concentration profile that is different from A, as

shown in Figures 2 and 3.
Comparison of Figures 1 to 4 shows that the performance of
Type II lies somewhere between Types I and III, which can
also be seen by considering Eqs. (15) and (16). In the limit as
V, goes to zero, these equations reduce to Eqs. (3) and (8),
respectively, and in the limit as V, goes to infinity (e.g., ap-
proaches the total volume of the reactor), these equations re-
duce, respectively, to Eqs. (9) and (11). Note also the start-up


S0.04 Reactants


0 2 4 6 B 10 12 14

10 18

Figure 1. Concentration profiles for start-up Type I.

Time, min
Figure 2. Concentration profiles for start-up Type II.

0 2 4 6 8 10 12 14 1 18 2
Time, min
Figure 3. Concentration profiles for start-up Type III.
Chemical Engineering Education

Type III has the shortest path to steady state and that at any
given time the concentration of any reactant or product in
this type is less than the concentration of the corresponding
component in other types.
It is interesting to consider in Figures 1, 2, and 3 the point
of intersection between a reactant concentration profile and
a product concentration profile, where they have equal con-
centrations-beyond this point the product concentration
exceeds that of a reactant. For A, this point has the same
value of concentration in all start-up types, but occurs at
different times. For Type I it occurs at a time less than the
time constant of the reactor, while for others its time is larger
than the time constant of the system. Thus, Type III is
preferable to the others.
Figure 4 shows that the overall temperature rise is not
great, because the presence of an inert solvent moderates the
temperature effects that would arise from thermal activity.
This will hold true even with more highly exothermic reac-
tions in the presence of diluents or a vast excess of one
reactant.12t Figure 4 also shows that the approach to steady
state is faster in the case of Type III than in the others. In
Type III the reactor is initially full, while in Types I and II
there will be an abrupt change at the moment the output
stream starts to flow, as seen for Types I and II. At any
given time, the temperature of the reacting system is
lower in Type III than in others, and this also supports
the choice of Type III.
Models of Type I need special attention during numerical
integration, specifically at zero time, in order to be able to
start the numerical solution. Such attention is not needed in
the other two types. Also, if we use concentrated solu-
tions, serious problems may arise during numerical inte-
gration that will affect the stability of the method unless
special techniques or packages are used. We do not need
this in the other types.
In Type I we might face experimental inconveniences,
particularly in measurements using conductivity meters, due

2 10 12 4 16 18 20
__Time, min
Figure 4. Temperature profiles for different start-up types
(, II III).
Fall 1997

to lack of material. Air bubbles and violence of mixing at the
beginning will affect the results; these effects might not
present a serious difficulty in the other types.

Questions for Consideration
1. Under what conditions can we apply Eq. (8) to
start-up Type II? Hint: compare Eq. (8) with Eq.
2. Derive Eqs. (17) and (18).
3. Explain, with the help of the model equations and
the nature of each start-up type, the above observa-

Thanks to Professor M.A. Soliman, J.O Wilkes, and the
reviewers of this article for their valuable contributions.

C Concentration of component i (reactant or product), mol/1
Cf Feed concentration of component i, mol/1
C,0 Initial concentration of component i, mol/1
C Steady-state concentration of component i, mol/1
cp, Heat capacity of component i, kJ/mol C
D Diameter of the reactor, m
F Total flow rate, 1/min
h., Heat transfer coefficient for air, kJ/m2 "C min
Hi Enthalpy of pure component i inside and at outlet, kJ/mol
Hif Enthalpy of pure component i in the feed, kJ/mol
k Reaction rate constant, 1/mol min
Q' Rate of heat loss to the surroundings, kJ/min
R Gas constant. 0.008314 kJ/mol K
S Surface area of the reactor, m2
T Temperature of the system and outlet, C
T mbTemperature of the surroundings, C
Tf Feed temperature, C
T Steady-state temperature, C
t Time, min
V Volume of the reacting system, 1
V, Starting volume of start-up Type II, 1
0 Time constant of the reactor, min
01 Time constant for Type II, min
AHr Standard heat of reaction, kJ/mol
o, Stoichiometric coefficient, positive/negative for products/
T Time for Stage 2, min

1. Abu-Khalaf, A.M., Chem. Eng. Ed., 28(1), 48 (1994)
2. Hill, G.C., An Introduction to Chemical Engineering Kinet-
ics and Reactor Design, 1st ed., John Wiley, New York, NY
3. Tsujikawa, H., and H. Inoue, Bull. Chem. Soc. Japan, 39,
4. Perry, R.H., and C.H. Chilton, eds., Chemical Engineers'
Handbook, 5th ed., McGraw-Hill, New York, NY (1973) 0



Pseudosteady-State Approximations

Colorado School of Mines Golden, CO 80401

undergraduate and graduate students completing their
first course in applied engineering mathematics or
transport phenomena are often confused about sev-
eral aspects of modeling physical systems. These may in-
clude clearly stating and understanding simplifying assump-
tions, advantages and limitations of various solution strate-
gies, ways to quickly check that derived solutions seem
reasonable using limiting cases, determination of applicable
ranges of approximate solutions, how to use limiting cases
obtained from exact solutions, and physical interpretation of
mathematical results. We have developed a pedagogically
sound approach to addressing these issues using a single
physical transport problem that can be analyzed with mul-
tiple mathematical models. The objective of this paper is to
present the problem with two pseudosteady-state solutions
and to provide several examples of study questions we pose
to students to help them better understand and interpret the
results of each solution.
The problem involves mass transfer from topical form-
ulations (ointments or creams applied to skin) containing
drugs in suspension. A moving boundary develops in this
system and mathematical representations are amenable to
pseudosteady-state, similarity transform, and regular pertur-
bation solutions. In this paper we formulate the descriptive
differential material balance model and obtain two different
pseudosteady-state solutions. We will also present and dis-
cuss several study questions to assign students based on
results of each model solution (presented in italics).

Delivery of drugs to skin is important for treatment of a
number of skin diseases. Many topically applied drugs are
solid suspensions in a vehicle consisting of an ointment or
cream base. That is, the total amount of active ingredient
exceeds the solubility limit of the formulation. In these sys-
tems, the solid drug dissolves into the vehicle, diffuses through
the vehicle to the skin, establishes local phase equilibrium

with the outer layer of skin, diffuses through the skin, and
finally is swept away by internal circulation. In many cases,
skin represents the rate limiting barrier for mass transfer.
Occasionally, particularly for highly insoluble suspension-
type formulations or for applications on damaged skin, the
primary mass transfer resistance will be the vehicle itself.
Release rates from topical formulations are experimen-
tally measured by spreading the drug suspension on a per-
meable membrane and then monitoring the appearance of
drug in an initially drug-free solution on the opposite side of
the membrane, the receiving chamber, as shown in Figure 1.
The receiving chamber volume is generally large enough so
that drug accumulation can be neglected. Mass transfer re-
sistances in the membrane are usually much smaller than in
the formulations, and the system can be treated as if the
membrane was not present. Consequently the concentration
in contact with the membrane is approximately the same as
the concentration of the receiving chamber (i.e., C = 0).
If the drug is finely divided, uniformly suspended, and
rapidly dissolves, then two zones will develop as illustrated
schematically in Figure 2. Far from the receiving chamber
(865xL), the drug will be present as a solid suspension at
the original starting concentration Co. In the region adjacent
to the receiving chamber (0ox<5), all of the solid will have
dissolved and the drug will be present in concentrations
below the solubility limit, Cs, as described by Fick's law."1

Annette L. Bunge is Professor of Chemical Engineering and Petroleum
Refining at the Colorado School of Mines, where she has taught and
conducted research since 1981. Her current research interests include
dermal adsorption of chemicals with application to health risk assessment
and drug delivery design.
Ronald L. Miller is Associate Professor of Chemical Engineering and
Petroleum Refining at the Colorado School of Mines, where he has taught
and conducted research in educational methods and multiphase fluid flow
for twelve years. He has received three university-wide teaching awards
and the Helen Plants Award for Best Workshop at the 1992 Frontiers in
Education national conference.
Copyright ChE Division ofASEE 1997
Chemical Engineering Education

The location of the sharp boundary between the fully dis-
solved and suspended drug zones (8) will advance in time as
required to satisfy the drug material balance at x=6(t):

(Co-Cs) d8 =DC(4)
dt (4)
8=0 at t=0 (5)
It is convenient to nondimensionalize the differential equa-
tions and restricting conditions using the following defini-

C, R
Co -Cos 1-R

L X=8/L
Cs Dt eDt
Co -Cs L2 L2


C Drug :
/ Suspended
Receiving Chamber :'ln'e ce i

Figure 1. Schematic diagram of an experiment to measure
drug release from a topical formulation containing sus-
pended drug.

4- Dissolved Zone --4-Undissolved Zone-l

Cs -


0 6 L

Figure 2. Schematic diagram of the concentration profile
in a vehicle containing suspended drug in contact with an
infinite sink.
Fall 1997

where R represents the ratio of CQ/Co, and e has been intro-
duced here in anticipation of its use in a regular perturbation
(1) solution. In dimensionless form, Eqs. (1) (5) become

doe a2
dX ad
dT ail

for 0!1


0=0 at Tr=0 for 20
0=1 at = for T>O
X=0 at T=0

The concentration profile of drug in the formulation can
then be determined by solving two coupled differential
equations, Eq. (7) and Eq. (8), for three conditions, Eqs.
(9) through (11).
The concentration profile is only occasionally of interest.
Practically, it is usually more important to determine quan-
tities such as the mass of drug released as a function of
time, the time required for all of the drug to dissolve, and
the fraction of the drug that is released when dissolution
is complete.
The amount of drug released from the vehicle at r = 0 per
unit of exposed area over a period of time from zero to t is
determined by integrating the mass flux at the vehicle re-
ceiving chamber interface over time. That is,
t T
MR=A D dt'= ALCo(1-R) f o dz' (12)
fR: x O -Xx=0d fDo (12)0
0 0
where t' and r' are dummy variables of integration. The
time required for all of the solid drug to dissolve ( tf) is the
time at which = 1, and the mass fraction released when all
of the drug dissolves is specified by Eq. (12) when = ,f.


When Co is much larger than the drug solubility C5, the
dissolution boundary 8 moves slowly relative to diffusion in
the dissolved zone. It is then appropriate to assume that the
concentration profile in the dissolved zone (0 !< "1 x ) is ap-
proximately at steady state. That is,

- =0

for 05

which is solved along with the conditions listed in Eqs. (9)
and (10) to give

e=1 (14)

where the movement of X in time is determined by substitut-
ing for 0 in Eq. (8),

That is,


ac aD2C
t 32
at Dx2

for 0


at x=0
at x=8

for t>0
for t<0

dX?= e1 (15)

which is integrated with Eq. (11) to give

x= 2Z (16)
Thus, the concentration profile of the drug in the formulation
is approximately represented by

0=- (17)
provided that C, << C (i.e., R << 1), guaranteeing that the
pseudosteady-state assumption is valid.
The amount of drug released from the vehicle at l = 0 per
unit of exposed area over a period of time from zero to T is

MR =ALCo(1- R)J 7 dt' (18)
MR ALCo( R),2( (19)

The time required for all of the solid drug to dissolve (zf) is
1/2, during which the mass fraction released is

MRf MRf 1-R (20)

According to Eq. (20), the fraction of the original drug mass
remaining in the formulation is R. Thus, according to the
pseudosteady-state solution, the average concentration in the
formulation when all of the drug has dissolved is C,, which
is not correct. If the concentration profile in the dissolved
regions varies linearly from C, to zero, the average concen-
tration when all the drug is dissolved should be C,/2.

More than thirty years ago, Higuchi121 used a variation of
the pseudosteady-state solution to obtain a different result.
Like the solution just described, Higuchi assumed that the
concentration profile had reached its steady-state value rap-
idly relative to the movement of the dissolution front (i.e.,
0=r l/). He chose, however, to determine the location of
the dissolution boundary by requiring that the mass of drug
that has left the formulation

L 8 L 5
MRA =LC- Cdx=LC- fCdx- fCodx=Co8- Cdx
0 0 8 0

be equal to the amount that has diffused across the boundary
at x=0 into the receptor

dM I1C
dMR =AD (22)
dt ix xm,
Written in dimensionless form, Eqs. (21) and (22) become

MR X-R Odl- l (23)
0 0

dMR CR (24)

Integrating Eq. (23), we obtain
MR =ALCo(1-R/2)X (25)
which can be then differentiated
dMR ALC(1- R/2)dx (26)
dt dt
and combined with Eq. (24) to yield
dX 1-R aO 1--R 1 )
dz 1-R/2a ByT1=X 1-R/2 X
Finally, Eq. (27) is integrated with the restriction that X=o
at = 0 to give

X 2(1-R)
X= [ (28)
Substituting Eq. (28) into Eq. (25), we obtain an expression
for the cumulative mass released,
MR =ALCo 2(1-R)(1-R/2)T= ALCo 2R(1-R/2)T/e (29)
which is slightly different than the pseudosteady-state result
given in Eq. (19). The dimensionless time required to com-
pletely dissolve the drug is
-R/2 (30)
f 2(1) (30)
2(1- R)
at which time the mass fraction released would be

MRf- MRf -R/2 (31)
According to Eq. (31), the fraction of the original drug mass
remaining in the formulation is 1-(1-R/2)=R/2. Thus, the
Higuchi solution correctly predicts that the average concen-
tration in the formulation when all of the drug has dissolved
is C,/2. Table 1 summarizes and compares expressions for
the pseudosteady-state and Higuchi solutions, respectively.

Which of the two pseudosteady-state solutions is likely
to be more correct (i.e., more closely match the exact
solution) when R is no longer very small?
Based on mass balance, the Higuchi solution is superior.
The Higuchi solution required that the mass of drug released
into the receptor and the mass remaining in the formulation
must always equal the total mass of drug in the original
formulation. A similar requirement was not made in the
standard pseudosteady-state solution. Most notably, at the
moment that all of the drug has completely dissolved, the
Chemical Engineering Education

pseudosteady-state solution predicts that the average con-
centration in the formulation is Cs, which is two times larger
than the correct value of CJ2.

What happens after the drug has completely dissolved?
Are the two pseudosteady-state solutions valid for all
times? If the solution is not always valid, when does
its validity expire? What happens then? How would
you describe the new situation?
The drug will continue to be released until the concentra-
tion reaches zero throughout the formulation. Equations (19)
and (29) describing the cumulative mass of drug released
only apply while some drug remains undissolved (i.e., as
long as T described by the solution of the unsteady-state diffusion
equation (e.g., by separation of variables) with an initial
concentration profile equal to the concentration profile in the
dissolved region when l = 1 (i.e., 0 = r at > cf) and no flux
at = 1. When T> Tf,

0= 2y (- sin(.m^ )e- T-Tf)/E
mO m

MR = MRf +2R- ( e-2m(T-Tf)/E

little drug will remain in the formulation once the drug has
dissolved. That is, for small values of R, I R/2 = 1.

What if the drug concentration in the topical formula-
tion is less than its solubility limit (i.e., Co < C,)? How
will the cumulative release rate from the formulation
compare with the case when suspended drug is present?
For the same drug concentration, will a dissolved or
suspended drug give a higher release rate?
An interesting exercise is to compare the release rate from
topical formulations containing suspended drug with the rate
from formulations containing only dissolved drug. When the
drug is entirely dissolved in the formulation, drug release
will be described by the solution of the unsteady-state diffu-
sion equation, Eq. (7), with an initial concentration of Co
throughout the formulation (i.e., 0= 1/R at = 0 for 0o < i 1)
and no flux at = 1. This is easily solved by separation of
variables to obtain

2 1 ?m2
S sin (m T)e-_ /

ALC=2 mO 1-e I

where X =(2m+1)7/2.
An interesting exercise is to ask students to show
that (MR -MRf)/(ALCo)= R/2 in the limit of large T. Thus,
in the limit of large T, the Higuchi solution correctly
predicts MR/(ALCo)=1-R/2+R/2=1, while the
pseudosteady-state solution predicts incorrectly that
MR/(ALC)= 1- R + R / 2 = R / 2 1. We note that for small
values of R, the solubility limit is very low, and consequently

Summary of Equations for Pseudo Steady-State and Higuchi Solutions

Quantity Pseudo Steady-State Solution

0 for 0<11TX
0 for X<11<1




Higuchi Solution


N l-R/2

(1- R)X = (1- R)- 2



(1- R/2)X = 2(1-R)(1-R/2)T



where Xm = (2m + 1)7/2. Although not obvious from Eq. (35),
for short times

MR = = (I2 R) (36)
ALCo K itR
which is the solution to Eq. (7) (most easily obtained by
Laplace transforms) when the formulation is semi-infinite
(i.e., L --) o or when T is short enough that the concentration
profile has not penetrated far into the formulation).
This is an interesting result, since for both suspended
and dissolved drug formulations, the cumulative mass
released is proportional to tE until changes in the
concentration profile have penetrated almost across
the formulation.

In this section, we present additional study questions
and exercises that can be assigned. We find that stu-
dents are usually more proficient at solving a problem
than at using the solution they have derived. With the
availability of symbolic mathematical tools such as
Mathematica or Maple, it is reasonable to ask students
to plot and analyze calculations from their solutions. A
goal of the questions posed here is to require students to
use and think about the physical meaning of their solu-

Fall 1997

tion. These exercises can be used in many different ways.
For example, we have assigned a series of solution strate-
gies as a take-home exam that students work on for several
weeks, submitting solutions to sections as they learn each
new solution method (a just-in-time approach). Alternatively,
they can be used as a series of homework or in-class prob-
lems illustrating many of the analytical mathematical tech-
niques chemical engineers need for solving partial differen-
tial equations (e.g., approximate solutions by pseudosteady-
state and regular perturbation, separation of variables, Laplace
transforms, and similarity transforms).
Plot the concentration profile as a function of dimen-
sionless position, x/L, in the formulation as predicted by
the standard pseudosteady-state and Higuchi solutions
at a given time for a specified R. Consider formulations
in which the drug is initially fully dissolved (i.e., R > 1)
as well as initially a suspended solid (i.e., R < 1).
Figure 3 shows C/Cs when R = 0.5, 0.8, 1, and 2 at T/E is
0.10. This is the appropriate way to plot concentration if R
changes as a result of changes in Co. An alternative plot of C/
Co is more suitable when the total amount of drug is held
constant and R changes by altering the formulation so that C,
changes, an analysis that can be tied to questions about
determining which formulation will be more efficacious (i.e.
more drug is released from the formulation during the same
amount of time). This plot is also useful for instructing
students about the limitations of approximate solutions. For
example, when R = 0.8 (i.e., Co/C, = 1.25), the pseudosteady-
state solution predicts a smaller slope (and thus a smaller
release rate into the receptor solution) than when C, is re-
duced to C, (i.e., R = 1). This is physically incorrect and a
result of the pseudosteady-state solution being used outside
of the appropriate range of R. This same inconsistency is not

0.0 6

0.2 0.4 0.6 0.8 1.0

Figure 3. Normalized concentration (C/C) as a function of
position (x/L) when R=0.5, 0.8, 1, and 2 at tIe is 0.10 as
predicted by the pseudosteady-state (S) and Higuchi (H)
solutions (while undissolved solid remains) or by the dis-
solved solid solution when R > 1.

observed for the Higuchi solution.
Calculate and plot the fraction of the initial drug mass
released as a function of =r e = Dt/L2 for different
values of the solubility ratio, R. Compare predictions
from the Higuchi and pseudosteady-state solutions
while suspended drug remains and then use Eq. (33)
to describe drug release after all of the drug has
Figure 4 presents the mass fraction released (i.e., MR/
(ALCo)) as a function of /E = -JDt/L2 for R = 0.2, 0.5, 0.9,
>1 as predicted by the pseudosteady-state (S) and Higuchi
(H) solutions while undissolved solid remains. The dashed
curves represent the solution when drug is completely dis-
solved (i.e., Eq. 33 when R < 1 and Eq. 35 when R > 1).
Significantly, the pseudosteady-state solution has lost mass
as indicated by the fact that the total mass fraction of drug
released approaches 1 R/2 instead of the correct value of 1.
The end point of the solid lines, indicated by either an H or
an S, represents the mass fraction of drug released during the
time required for all of the drug to dissolve (i.e., f/ le).
When the total amount of drug provided greatly exceeds its
solubility limit (i.e., R is small), undissolved drug remains
for a long time. But as R approaches one, the drug excess
over the solubility limit decreases with a consequent de-
crease in time for complete dissolution.
How does the cumulative amount of drug release vary
with time (does the rate increase, decrease, or stay
constant)? Is there a steady state? Consider formula-
tions in which the drug is initially fully dissolved (i.e., R >
1) as well as initially a suspended solid (i.e., R < I).

Figure 4. Mass fraction released (i.e., MR/ALC) as a func-
tion of /I=V Dt/L2 for R equal to 0.2, 0.5, 0.9, > 1 as
predicted by the pseudosteady-state (S) and Higuchi (H)
solutions (while undissolved solid remains) or by the dis-
solved solid solutions (indicated by dashed curves).
Chemical Engineering Education

jDIZ 2

As indicated in Eqs. (19) and (30) and illustrated in Figure
4, the mass fraction released is proportional to the square
root of time as long as some drug remains as a suspended
solid. When the formulation initially contains only dissolved
drug, the mass fraction released is still proportional to the
square root of time as long as less than about a third of the
original mass is released. This problem does not reach steady
state (except when all of the drug has left the formulation).
Federal regulations require that labels indicate the con-
centration of active ingredient in a topicalformulation.
If the concentration of a suspended active ingredient is
the same, but the solubility in two formulations is differ-
ent, which formulation will be more effective (i.e., de-
liver drug at a higher rate)?
The answer to this question is provided in Figure 4, which
illustrates the case when the total amount of drug remains
constant but the formulation is altered to increase the solu-
bility limit C,. The formulation with the higher solubility
should deliver drug more rapidly. Increasing the solubility
limit (increasing R) increases the amount of dissolved drug
available for diffusion across the formulation. The Higuchi
solution predicts this expected result (i.e., that increasing R
should increase the rate of drug release into the receptor
solution). By contrast, the pseudosteady-state solution fails
when R approaches 1, incorrectly predicting that the release
rate is smaller when R = 0.9 than for R = 0.2 or 0.5.

How does increasing the amount of drug affect the
cumulative mass released if the solubility limit is fixed?
Consider formulations in which the drug is initially
fully dissolved (i.e., R > 1) as well as initially a sus-


0.5 1.0

1.5 2.0

pended solid (i.e., R < 1).
If the solubility limit is fixed, increasing the initial drug
concentration will cause R to decrease and will increase the
release rate into the receptor solution, as shown in Figure 5.
(Again, the pseudosteady-state solution erroneously predicts
that decreasing R from 1 to 0.9 causes the release rate to
decrease). If R < 1, the release rate is limited by the drug's
solubility in the vehicle, and increasing the total drug con-
centration does not proportionally increase the release rate
(e.g., compare R = 1 and 0.5). The pseudosteady-state solu-
tion predicts that the rate of release is proportional to
VCo-Cs; the Higuchi solution predicts the release rate is
proportional to VCo-Cs/2.

In this paper we have used mass transfer from topical drug
formulations to illustrate development of two pseudosteady-
state solutions and provided several study questions that can be
used to help students become better mathematical modelers.

A Area of vehicle application
C Concentration of drug in the vehicle, mass/volume
Co Original concentration of drug in the vehicle, mass/volume
Cs Solubility concentration of drug in the vehicle, mass/

D Effective diffusivity of drug through the vehicle
L Thickness of the vehicle
m Index on summation, Eqs. (32) (35)
M Mass of drug originally present in the formulation, ALC
OR Cumulative mass of drug appearing in the receiving
4 Cumulative mass of drug appearing in the receiving
chamber during the time required for all of the drug to
R Ratio of the solubility concentration to the original drug
concentration, Cs/C
t Time since application of the drug suspension
x Axial position in the vehicle
eek Letters



Dissolution front position in the vehicle
Ratio of C to the difference between Co and C, Eq. (6)
Dimensionless axial position in the vehicle, Eq. (6)
Eigenvalue in Eqs. (32)-(35), = (2m + 1)n / 2
Dimensionless concentration in the vehicle, Eq. (6)
Dimensionless time, Eq. (6)
Dimensionless time required for all of the drug to dissolve
Dimensionless dissolution front position in the vehicle,
Eq. (6)

Figure 5. Mass fraction released divided by R (i.e., M,/
(ALC)) as a function of E = Dt/L2 for R equal to 0.2,
0.5, 0.9, and 1 as predicted by the pseudosteady-state (S)
and Higuchi (H) solutions (while undissolved solid re-
mains) or by the dissolved solid solutions (indicated by
dashed curves).
Fall 1997

1. Paul, D.R., and S.K. McSpadden, "Diffusional Release of a
Solute from a Polymer Matrix," J. Membrane Sci., 1, 33
2. Higuchi, T., "Rate of Release of Medicaments from Oint-
ment Bases Containing Drugs in Suspension," J. Pharm.
Sci., 50, 874 (1961) O

S9--------- 0.
- --- -- ------------

n . .




Purdue University e West Lafayette, IN 47907

he chemical engineering curriculum in the United
States has trained generations of technical experts
who have successfully optimized chemical processes
and products once they entered the chemical industry. The
U.S. chemical industry, however, has entered a critical stage
in which it must be able to create new and differentiated
value through technical innovations that are essential for
long-term survival. This innovation process will require new
skills that go far beyond the traditional expertise for the
optimization of tasks possessed by young chemical engi-
neers. The innovators must be able to identify new opportu-
nities, explore the boundaries of technology, evaluate criti-
cal issues, develop and implement technologies, and com-
municate effectively with scientists and engineers from
other disciplines. Therefore, one of the most important
educational tasks of a modern university, in combination
with a strong theoretical foundation, is to challenge stu-
dents in laboratory courses to think, explore, hypoth-
esize, plan, solve, and evaluate.
The typical sequence of laboratory skills development
stops short of introducing young engineers to the most criti-
cal aspects of experimental work. Chemical engineers usu-
ally begin developing their laboratory skills in chemistry
courses, where experiments are closely managed. At this
early stage in their development, students follow detailed
instructions and learn basic principles by observing the re-
sults. In the undergraduate engineering laboratory course
(the "unit operations lab"), students have more freedom in
experimental design but still have well-defined objectives
and manipulate equipment someone else has set up.
It is rare, however, for undergraduate students to be taught
how to create new experiments. It is also rare for under-
graduate students, and hence beginning graduate students, to
have an appreciation for the care, planning, design, and
testing required to produce equipment that will give reliable
and useful results. Even such simple issues as leak testing or
adapting analytical devices to new tasks are outside most

* Department of Chemistry, Purdue University, West Lafayette
IN 47907

students' experience. Even more important is an absence of
opportunities to learn how the lessons learned from the fail-
ure of an approach can be fed back into the empirical process
to seed the finally successful idea. All these skills require
more creative freedom than is usually allowed in a well-
structured laboratory course. In the novel laboratory teach-
ing approach described here, we try to provide students with
a learning environment that allows them to develop ad-
vanced experimental skills that are necessary for success in
research and development environments.

A true opportunity for students to discover and develop
experimental skills is expensive in both hardware and the
recurring costs associated with providing the freedom to

Jochen Lauterbach is Assistant Professor of Chemical Engineering at
Purdue University. He received his Diploma in Physics from the University
of Bayreuth, Germany, in 1992 and his PhD in Chemistry from the Free
University of Berlin, Germany, in 1994. His research focuses on nonlinear
phenomena in heterogeneous catalysis, imaging surface processes in situ
with ellipsomicroscopy, and the characterization of polymer-metal inter-
faces using surface second harmonic generation.
Scott R. White is a PhD graduate student in Science Education at Purdue
University. He received his BS in Chemistry and Secondary Education
Certification in 1992 from Harding University. He received his MS in
Chemistry from Purdue University in 1996 with G.M. Bodner. His research
interests are in teaching and learning in science and curriculum reform.
Zhufang Liu is a research associate in the School of Chemical Engineer-
ing. He is responsible for the Dow Advanced Instrumentation Laboratory
and designs and develops new experimental procedures. He received
both his BS in Chemical Engineering (1983) and his MS in Polymer
Science (1986) from Tianjin University, China, and his PhD in Chemical
Engineering from the University of Virginia (1995).
George M. Bodner is Professor of Chemistry and Education at Purdue.
He received his BS in Chemistry from the State University of New York,
Buffalo (1969) and his PhD in inorganic and organic chemistry from
Indiana University (1972). His research interests are learning theory,
overcoming barriers to curriculum reform, and understanding the condi-
tions for appropriate use of technology in teaching and learning chemistry.
W. Nicholas Delgass is Professor and Associate Head of Chemical
Engineering at Purdue University. He receive his BSE degrees in Chemi-
cal Engineering and Mathematics at the University of Michigan in 1964
and his MS (1966) and PhD (1969) degrees in Chemical Engineering from
Stanford University. His teaching interests are in reaction engineering,
catalysis, the chemical process industry, and laboratory. His research is
on kinetic and spectroscopic characterization of heterogeneous catalysts.
He is the co-editor of the Journal of Catalysis.

Copyright ChE Division ofASEE 1997

Chemical Engineering Education

make mistakes. This expense is often a strong deterrent to
the development of the laboratory content of chemical engi-
neering curricula. We have been fortunate to have the inter-
est and commitment of the Dow Chemical Company in this
educational investment in future experimentalists. Dow's
financial support has made possible this version of the labo-
ratory and the educational opportunities it affords. We note,
however, that the concept of combining the research in chemi-
cal engineering at the host institution with the experimental
expertise of interested faculty and equipment dedicated to
support students is a portable one and can provide a vehicle
for exporting this approach to laboratory instruction virtu-
ally anywhere. At Purdue, equipment has been chosen to
allow us to design projects that involve a variety of experi-
mental techniques in which new apparatus can be created.
The projects in the early stage of this course are planned so
that future generations of students will benefit from the new
instrumentation. They may then, for example, modify the
existing equipment for their purposes.
The initial focus of the lab development project has been
in adsorption, catalysis, and reaction engineering. Instru-
mentation available in the teaching laboratory includes
A Fourier transform infrared spectrometer for
molecular identification of adsorbed or gas phase
A mass spectrometer for chemical analysis of
atmospheric streams from reactors or adsorption
A scanning force microscope for topographical
analysis at the nanometer scale
A surface area and pore structure apparatus for
analysis of active porous materials such as catalysts
An atomic adsorption spectrophotom-
eterfor elemental analysis of solids T
A gas-chromatograph for chemical Lec
reaction analysis
How to perform
COURSE STRUCTURE, Data acquisition
Experiments for this course were piloted Vacuum techn
with two separate groups of honors students Flanges and fit
in 1994 and 1995. In the spring semester of Scientific writi
1997, the course was offered the second time Scientific oral
at Purdue. Over twenty students were inter- Molecular vibr
ested in this novel course approach, but due Vibrational spe
to space limitations, only twelve could be aspects
admitted to the course. The student body was Heterogeneous
heterogeneous, consisting of three chemical Adsorption and
engineering juniors, one chemical engineer- Thermal desor
ing senior, one chemistry senior, four chemi- Scanning probt
cal engineering graduate students (first and
Fall 1997

second year), two chemistry graduate students (first and
third year), and one materials engineering graduate student
(first year). In contrast to the previous years, the undergradu-
ate students were not honors students, but experimentally
interested students with various grade point averages.
The students were divided into three groups of four and
each group was given an open-ended project. The project
descriptions provided the groups with an overall project
objective and a well-defined starting point, but required
them to develop and pursue their own research ideas. When
the groups were organized, care was taken to obtain an equal
distribution of students of different levels, departments, and
gender for each group, simulating an industrial research
environment. For most students, this course was their first
experience in a group where graduate and undergraduate
level students from different backgrounds had to work to-
gether to achieve a common goal. In the beginning, the
students had to assign the roles of leader, experimentalist,
and analyst among the group members. The diversity of the
groups clearly added a learning dimension. The course was
also successful with undergraduate chemical engineering
students only, however. While those groups were honors
students, it is our belief that a genuine interest in the hands-
on aspects of chemical engineering is more important than
the students' grade point averages.
The total time allotted for the course was two three-hour
blocks per week. A combination of approximately 80% labo-
ratory time and 20% lecture time was chosen to give the
students enough time to gain hands-on experience with de-
signing, building, and testing effective experimental equip-
ment and adapting modern analytical instrumentation for
chemical engineering measurements. A conference room
was chosen over a classic classroom setting for lectures and
for student presentations to facilitate dis-
cussions between the students.
LE 1
T IThe lectures were concentrated in the
first six weeks of the semester (two hours

successful literature of lecture per week) and covered a variety
of topics in instrumentation, molecular-
programming of level measurements, and computer data
tion acquisition. The diverse backgrounds of
the students required implementation of a
teaching philosophy that started with ba-
sics and built progressively and at a rea-
ntations sonably fast pace to a deeper and more
applied level. Lectures and demonstra-
copy-experimental tons were also given in scientific writing,
literature search, and oral-presentation
ysis-an overview skills. A summary of topics covered in
rption the lectures can be found in Table 1.
spectroscopy There were no quizzes, tests, or final
oscopy exams for this course. Student evaluation
was based on three major factors:


n a su

n and

e micr

Performance in the laboratory (motivation, ideas,
group dynamics, results)
Oral presentations (one 15-minute talk for each
group member during the semester as well as so-
called 5-minute updates every Tuesday morning,
showing progress and drawbacks encountered
during the last week and encouraging student
Written reports (each group wrote a total of three
reports about their progress during the semester)

While the evaluation for the first two points was on an
individual basis, all group members received the same grade
for their reports, motivating them to work closely together.
The students were asked to turn in their individual contribu-
tions to the papers, not for grading purposes but to help them
improve their writing skills and to provide them with indi-
vidual feedback if necessary.

One project was given to each of the three student groups.
These projects were designed in advance by the instructors
around space and instrument-use limitations. Due to the
open-ended nature of the projects, it was not possible to plan
the whole course in advance-which at a later stage in the
semester caused some logistical problems when more than
one group wanted to use the same instruments (this problem
was solved by offering extra laboratory hours). Due to the
open-ended nature of the research projects, it proved to be
important to closely monitor students' progress, without im-
posing the instructors' opinion on their approach. Frequent,
open discussions with the group were by far the most effec-
tive way to guide their research.
Project 1 involved the synthesis and characterization of
the mesoporous materials MCM-41 and ZSM5. The students
were motivated to study the effects of process variables on
the zeolite properties, such as pore size and acidity. Avail-
able instrumentation for this project was a physisorption
apparatus, atomic absorption, X-ray diffraction, mass spec-
troscopy, and nuclear magnetic resonance. This project had
no major design component and therefore was able to make
use of a wider variety of techniques to characterize the
chosen materials.
Project 2 involved the design and construction of an IR
transmission cell to perform an IR spectroscopy study on
supported catalysts. The students built the reaction cell around
a 2 3/4-inch Conflat cross, which was provided to them as a
starting point. The students then had to design a sample
holder with heaters and thermocouples, a simple gas inlet
system with flowmeters, and a gas analysis system using the
given mass spectrometer setup. After several attempts and
many iterations with the instructors, the. final design was
built by the chemistry machine shop. During this process,

the students learned that it is important to pay attention even
to minor details, such as the material used for the screws or
how to attach CaF2 windows to a metal flange. The reaction
chosen by the instructor was CO oxidation, and the students
opted for a SiO2-supported Pt catalyst, which they prepared
and characterized with atomic absorption, scanning electron
microscopy, and chemisorption. The C-O stretching vibra-
tion of CO adsorbed on the Pt particles was observed during
adsorption, desorption, and reaction conditions.
Project 3 will be discussed in detail. It included design
and construction of an attenuated total reflection (ATR) IR
cell to perform liquid-phase IR measurements. The group
was composed of a third-year chemistry graduate student, a
first-year chemical engineering graduate student, and two
chemical engineering juniors. The objectives of the project
were to teach the students how to design and build an
optical device from scratch and how to perform IR vibra-
tional spectroscopy.
The students were asked to design and build an ATR cell

Design of ATR Cell and LABVIEW Programming


Fourier transform infrared spectroscopy
Attenuated total internal reflectance
Infrared optics
IR sampling of liquids
Virtual instrumentation
LABVIEW instrument interface programming
Mass spectroscopy

This project is divided into two separate parts, which in the
beginning will have to be performed simultaneously. First of all, we
are interested in the control of the quality of liquids. For that purpose,
we want to use Fourier transform IR vibrational spectroscopy to obtain
vibrational spectra of liquids. We will use attenuated total internal
reflectance spectroscopy (ATR), a powerful and versatile tool for IR
liquid sampling. The group has to design and realize a small ATR cell
including the IR optics, which will fit into the sample compartment of
the FTIR spectrometer available in the Dow lab. Since more than one
group will use the FTIR spectrometer during the semester, the ATR
cell has to be portable, and easy installation and removal are important
design criteria. The instructor will provide an ATR crystal for the
group as a starting point for developing the ATR cell. Once the cell is
completed and tested, you will perform experiments with several
liquid samples.
The second task of the project is to learn the basics of the
programming system LABVIEW and to program a control interface
for the LEYBOLD mass spectrometer (manuals and basic software
tools will be provided). This program will also manage the heating
controller for thermal desorption spectroscopy. Both instruments
communicate with a Power MAC via a serial port interface. Groups #1
and #2 will depend on the timely "delivery" of this program package,
since they will use the interface to take valuable thermal desorption
data. Therefore, coordination of the time schedules between all groups
is necessary and should be performed by the leaders of each group.

Figure 1. Information given to the students of Group 3
at the beginning of the course.
Chemical Engineering Education

out of commercially available optical elements. ATR spec-
troscopy was chosen because it is an effective method for
liquid IR sampling, sample liquids are easy to handle, and
the overall cell design can be relatively simple. Design con-
straints given to the students in advance were that the cell
must fit into the sample compartment of the available Nicolet
550 FTIR spectrometer. In addition, the instructors had or-
dered a 450 trapezoidal zinc selenide (ZnSe) crystal of di-
mensions 50x20x2 mm as the ATR element to avoid major
time delays for the students. The ATR cell had to be easily
removable from the sample compartment, since Project 2
also made use of the FTIR spectrometer during class peri-
ods. A starting budget of $1,000 was given to the group.
The secondary objective of this project included the imple-
mentation of a temperature controller and a mass spectrom-
eter data acquisition module in LABVIEW. This addition
to the main project was chosen to bridge time gaps while the
group was waiting for parts ordered or being machined.
Figure 1 shows the original project description given to the
students during the first class period.
In the beginning, the students felt this project assignment
would be almost impossible to accomplish. None of the
students in the group had any research-based experience
with IR vibrational spectroscopy or design of optical compo-
nents. The students set out to find information about IR
spectroscopy in general and publications about other ATR
cell designs. Their first thought was to find other designs
in the scientific literature or manufacturer's catalogs and
to simply "copy" one of them. They soon realized that
the available information in the literature was sparse and
the majority of the descriptions were not useful in de-
signing their own cell.
During this first week, the instructor (who had done a
literature research prior to the class) was available for dis-
cussions when students needed him, but he did not interfere

or direct the information-gathering process. The students
realized that they had to start their own thinking process,
which required a better understanding of the underlying
physical principles.
The group started to postulate design concepts. During
this phase, it was important for the instructor to give sugges-
tions while preserving the students' freedom to develop and
pursue their own ideas. For example, the students soon found
out that it is necessary to focus the IR beam on the entrance
slit of the ATR crystal and immediately associated "fo-
cus" with "lens." Therefore, their first idea was to use
silica or plastic lenses in their design. At this point, the
instructor had to alert the students to the fact that lenses
for IR wavelengths have to be made out of special mate-
rials in order to be transparent.
After the students had been encouraged to look at other IR
beam designs and at the FTIR spectrometer in the lab, they
came to the conclusion that gold-coated focusing mirrors
would be the way to go. Further problems that had to be
solved were the construction of the liquid sample holder and
the holders for the optical components. Several design
iterations and many discussions followed. After three
weeks, the students had decided on their final design,
which allowed them to stay within the budget. This group
finished their design and construction of an ATR cell
(shown in Figure 2), the total cost of which was about
30% of commercially available cells!
Students and instructors agreed that the final term paper
should be written in the form of a scientific paper, which
could be submitted to a scientific journal. After the cell
design was finished and the cell was extensively tested with
IR grade fluids, the students had eight lab periods left in the
semester to perform experiments, which they planned on
their own. For most of them, this high degree of freedom
was unique compared with previous experiences in other
laboratory classes. The group chose to compare various grades
of gasoline, which they collected from local gas stations.
We think that the possibility of performing experiments
with the equipment they designed and built is important in
making this course a satisfying experience for students. There-
fore, progress of the students should be monitored closely by
the instructors to ensure that design and construction are
finished with at least four weeks left in the semester.

During the semester, the students were closely monitored
by an educational researcher from the Division of Chemical
Education in the Department of Chemistry at Purdue Uni-
versity. The project evaluation was done using Action Re-
search as the methodology.[1,21 Qualitative Action Research
is an informal, formative, interpretive, and experiential model
of inquiry in which everyone involved in the study is an
active, knowing participant.[3'41 The knowledge sought was

Figure 2. ATR cell design by the students in Project 3.
Fall 1997

"what worked and why," and "what needs to be changed for
the next class?" The educational researcher spent every mo-
ment he could with the students and the instructors during
the scheduled class time. Data were collected from a variety
of sources, including oral and written field notes, video tapes
of the presentations and lectures, group lab reports, student
written evaluations, student interviews, and conversations
with the instructor. Oral data were transcribed for analysis,
and inductive analysis[5'61 was used to find emergent patterns
in the data. Inductive analysis is a method used in qualitative
research that allows meaningful categories and themes to
develop from the raw data, such as transcriptions and field
notes. Reading, categorizing, and re-categorizing data pat-
terns through the whole evaluation period over time allowed
the students' and instructor's words, actions, and interests to
become clearly organized into knowledge claims that could
inform the instructional practice of the course. Four emer-
gent knowledge claims at the writing of this paper are:

1. Groups that are mixed by academic experience can
work well and benefit everyone.

The factor that added the highest degree of complexity to
the course was the mixture of undergraduate students and
graduate students in each group. The groups were allowed to
negotiate for themselves who would be the group leader. A
graduate student emerged as the group leader in each group,
but the interpretation of what it meant to be a leader varied in

each group. Due to the long-term nature of the projects,
everyone in each group needed and gained a basic under-
standing of every aspect of their group's project. The under-
graduates attributed much of their self-improvement in their
technical writing skills and experimentation skills from work-
ing with graduate students as peers in their groups. Due to
the collaborative nature of the projects, full participation in
every aspect of the group's project was required of each
group member, and for the most part undergraduate and
graduate students took over equal research responsibilities.
One graduate student commented, "It would have been im-
possible for one of us to have done all the work and come up
with all the ideas. I have my own research to do. The under-
graduates worked really well with us." Most of the coopera-
tive learning literature is devoted to groups of the same age,
grade, or course level.[7] In this course, not only was there a
horizontal relationship among the students due to the differ-
ent areas of study, but also there was a perceived vertical
relationship due to academic experience status.

2. The traditional roles of leader, experimentalist, and
analyst were initially assigned, but the borderlines be-
tween these categories were often crossed.

In order for the groups to function properly, every member
of each group needed to develop a basic understanding of
every aspect of the group's project. Due to the large nature
of the projects, no one person (including the instructor)

Student Comments

Assertion I
"Having graduate and undergraduate students in the same group
was a definite benefit. The diversity was something that we
(undergraduate students) never would have experienced otherwise.
Working with them allowed us the chance to benefit from their
skills. Now I know that there are real people behind those doors in
the building. I know more now what they do and how they
approach problems."
"The course could be divided into undergraduate and graduate
students, with the undergraduates working in a more controlled
environment. The course went fine, but it would be interesting to
see what the graduate students could do if they were by them-
Assertion 2
"We tried to keep the roles through the first paper, but they just
didn't work out, except for the group leader. That was something
that stayed the same."
"I wrote up a complete section of the second paper on TPD from the
background and theory to our experiments. I was an analyst at the
first, but I guess we all kind of... took care of our own areas. The
roles didn't do too much for us."
"I have learned lots of lab techniques and benefited from working
with others who are not in my major, learned to see things from a
different point of view. As well I have learned things that I hadn't
expected like how to use what I know and combine it with what I
don't know, and what my group members know to solve a

* "I have increased my problem solving abilities. My analytical
thinking has changed as well as how I look at things. See the forest
not the trees."
"I think one of the best qualities of this course was the flexibility
given to the students on the projects. To actually plan, design,
construct, and implement a tool is very rewarding. The very fact
that the design begins from scratch forces us to understand every
part of the process."
Assertion 3
"The presentations were good. We got to see what other people
were doing instead of just hearing about our own project. The other
groups were doing some things that related to our experiments."
"The discussions and lectures were okay. Sometimes they went a
little long and cut into our lab time. That made it difficult some
days when you only had a certain number of days on the
"My technical writing has greatly improved. Working with the
graduate student helped, and I got to be sort of an 'expert' on a
process and a piece of equipment."
Assertion 4
"In other unit-ops labs they [the instructors] set the standards, or
they have been set since time began. Here we set our own
standards and deal with problems that come up. It's up to us to fix
"I think the freedom and responsibility we had in the course is one
of the greatest parts of it. We were able to do what we needed to do
to solve the problems to reach our goals."

;64 Chemical Engineering Education

could have made all of the content, design factor, and experi-
mental design decisions for the group. Each member of the
group was required to make two presentations during the
semester, a task usually assigned to the group leader in
traditional laboratory courses. Therefore, the members of
each group became "experts" on a particular instrument,
content, or experimental process. Each member of the group
was involved in the experimentation and/or analysis of each
aspect of the project. Although there was a graduate student
in each group who served as a group leader, each described
his/her role as more of a group-organizer/facilitator than as a
leader who told everyone what to do.

3. The written reports and presentations afforded the
students freedom to improve their own knowledge
throughout the semester.
The groups were required to turn in three formal written
reports during the semester. An exciting observation was
made after the first reports were graded and handed back to
the students: the students separated the graded reports into
sections for each group member to work on; the comments
and suggestions written on their reports were used to im-
prove their existing experimental procedures and to improve
their technical writing in subsequent papers. The researcher
had never observed this in the traditional chemical engineer-
ing laboratory classrooms. The students, especially the un-
dergraduates, gave great praise to the Tuesday-morning pre-
sentation time, which obviously helped them to improve
their own presentation skills. But the students also said that
this time helped them improve their "presentation listening/
comprehension" ability. By listening to all of the presenta-
tions from every group, the students were exposed to a
greater knowledge base than if they had only heard the
presentations from their particular group. Many of the "Five-
Minute/One Overhead" talks were followed by 10-15 min-
utes of questions and discussion. Two undergraduates, how-
ever, felt intimidated due to the content level of questions
and discussion. Their major complaint was that the ques-
tions and discussion were sometimes based on knowledge
that was neither based on nor developed in the course itself.
The remainder of the undergraduates also felt a similar de-
gree of intimidation, but realized that research is not exactly
like a classroom; one undergraduate noted, "You have to
utilize knowledge from wherever you can."
The setting of the Tuesday-morning talks was also impor-
tant. The setting was not a classroom, but a conference
room. Instead of sitting in desks, all facing the front, every-
one sat in comfortable chairs arranged in a "U." This pro-
vided an atmosphere that was more like a community of
researchers rather than a classroom of individuals.
4. The students used their experimental freedom for
taking ownership and responsibility for their own knowl-
edge and skills.

Fall 1997

In each of the interviews, the students praised the freedom
that the design of this course allowed them to have, as
compared with traditional laboratory courses they had expe-
rienced. This course allowed them to "set their own stan-
dards," "set and achieve their own goals," and "make
mistakes, and change things to fix them." The students
described other laboratory courses as "being told what to
do" in order to "give them [the instructors] what they
wanted for the points." Other representative comments
can be found in Table 3.

We have reported a novel approach to laboratory teaching
for undergraduate and graduate students providing degrees
of research freedom atypical for chemical engineering labo-
ratory instruction. Judging from our experience with this
course and the student feedback, we can conclude that the
approach provides valuable training for every student inter-
ested in learning more about experimental work. We expect
the course to become an elective course in Purdue's chemi-
cal engineering curriculum. The concept is portable to other
universities. The main ingredient is a cluster of interested
and experimentally oriented faculty willing to design course
projects and seek the optimum level of monitoring to maxi-
mize student success in independent work. The scope of
projects will, of course, depend on equipment available for
student use. As with any new course, the faculty time com-
mitment is largest the first time through when all the projects
are new and untested.

We are grateful to the Dow Chemical Company for its
interest in, commitment to, and financial support of this
educational investment in future experimentalists. We
also thank Dr. David Taylor in the School of Chemical
Engineering for assistance in specifying and setting up

1. Carr, W., and S. Kemmis, Becoming Critical: Education,
Knowledge and Action Research, 2nd ed., Falmer Press,
New York, NY (1986)
2. Kemmis, S., and R. McTaggart, The Action Research Plan-
ner, 2nd ed., Deakin University Press, Warun Ponds, Aus-
tralia (1982)
3. Grundy, S., Curriculum: Product or Praxis? Falmer Press,
New York, NY (1987)
4. MacIsaac, D., "Curricular Reformation in Computer-Based
Undergraduate Physics Laboratories via Action Research,"
PhD. Thesis, Purdue University (1994)
5. Geotz, J.P., and M.D. LeCompte, Ethnography and Qualita-
tive Design in Educational Research," Academic Press, San
Diego, CA (1984)
6. Patton, M.Q., Qualitative Evaluation and Research Meth-
ods, 2nd ed., Newberry Park, Sage (1990)
7. Nurrenbern, S., Experiences in Cooperative Learning, Uni-
versity of Wisconsin Press, Madison, WI (1995) O



Akron, University of..................... ..................... 268
Alabama, University of ........................................ 269
Alberta, University of.................................... 270
Arizona, University of ......................................... 271
Arizona State University ......................................... 272
Auburn University ............................ .............. 273
Brigham Young University .......................................... 363
British Columbia, University of .................................... 363
Brown University .......................... ........... 379
Bucknell University .............................................. 379
Calgary, University of ................................................. 274
California-Berkeley, University of................................ 275
California-Davis, University of ................................... 276
California-Irving, University of.................................... 277
California-Los Angeles, University of ........................ 278
California-Santa Barbara, University of ...................... 279
California Institute of Technology .............................. 280
Carnegie-Mellon University ........................................ 281
Case Western Reserve Universtiy ............................... 282
Cincinnati, University of ............................................ 283
Clarkson University ............................................ 284
Clemson University ............................................ 285
Cleveland State University ............................................ 364
Colorado, University of .............................................. 286
Colorado School of Mines ............................................. 287
Colorado State University ............................................. 288
Columbia University .................... .......................... 364
Connecticut, University of........................................... 289
Cornell University .................... ....................... 290
Dartmouth College ............................................ 365
Delaware, University of.................................... 291

Drexel University .................................. .............. 365
Edinburgh, University of ............................................ 379
Florida, University of ................................................. 292
Florida A&M/Florida State University ....................... 293
Florida Institute of Technology ................................... 294
Georgia Institute of Technology .................................. 295
University of Houston ...................... ...................... 296
Howard University ............................ ............... 297
Idaho, University of............................. ....... 366
Illinois-Chicago, University of ..................................... 298
Illinois-Urbana, University of ..................................... 299
Illinois Institute of Technology ................................... 300
Imperial College ...................... ....................... 366
Iowa, University of..................... ................. 301
Iowa State University ........................................... 302
Johns Hopkins University........................................ 303
Kansas, University of ........................ .................... 304
Kansas State University ............................................... 305
Kentucky, University of ............................................. 306
Lamar University ................................ ................ 367
Laval University ............................... ..................... 307
Lehigh University ...................... ..................... 308
Loughborough University ........................................... 367
Louisiana State University .......................................... 309
Louisiana Tech University ................................... 368
Louisville, University of........................................ 368
Maine, University of........................... ........... 310
Manhattan University ............................................ 311
Maryland-Baltimore County, University of ................ 312
Maryland, University of ........................................ 313
Massachusetts, University of.................................... 314

Chemical Engineering Education

Massachusetts-Lowell, University of ........................... 380
Massachusetts Institute of Technology ....................... 315
McMaster University .......................................... 369
Michigan, University of.......................................... 516
Michigan State University ......................... 317
Michigan Technological University .............................. 318
Minnesota, University of ........................................ 319
Missouri-Columbia, University of................................. 369
Missouri-Rolla, University of..................................... 320
Monash University ............................................. 370
Montana, University of.................................... 380
Nebraska, University of....................................... 321
New Jersey Institute of Technology ............................ 322
New Mexico, University of ......................................... 323
New Mexico State University ..................................... 370
New South Wales, University of ................................ 371
North Carolina A&T State University ......................... 371
North Carolina State University .................................. 324
North Dakota, University of ........................................ 380
Northeastern University........................................ 372
Northwestern University ............................................ 325
Notre Dame, University of ......................................... 326
Ohio State University .................................................. 327
Ohio University ......................... .................. 328
Oklahoma, University of ...................................... 329
Oklahoma State University.......................................... 330
Oregon State University .............................................. 331
Ottawa, University of ................... ..................... 372
Pennsylvania, University of........................................... 332
Pennsylvania State University ..................................... 333
Pittsburgh, University of .......................................... 334
Polytechnic University ..................... ...................... 335
Princeton University ...................... ..................... 373
Purdue University ......................... ................ 336
Queensland, University of ................................. 337
Rensselaer Polytechnic Institute ................................. 338

Rhode Island, University of........................................... 373
Rice University ............................................ 339
Rochester, University of....................................... 340
Rose-Hulman Institute of Technology ........................ 374
Rutgers U university ........................ ........................... 341
South Carolina, University of...................................... 342
South Dakota School of Mines .................................... 380
South Florida, University of ........................................ 374
Southern California, University of .............................. 375
State University of New York, Buffalo ....................... 375
Stevens Institute of Technology .................................. 343
Sydney, University of.................................................. 376
Syracuse University ...................... ....................... 376
Tennessee, University of ............................................... 344
Texas, University of ........................ ....................... 345
Texas A&M University .................... ........................ 346
Texas A&M University-Kingsville ............................... 377
Toledo, University of....................... ...................... 347
Tufts University ............................... .... ........... 348
Tulane University ................................................... 349
Tulsa, University of ......................... ..................... 350
Utah, University of ........................................... 377
Vanderbilt University .............................................. 351
Virginia, University of ........................................... 352
V irginia Tech ................................................. 353
Washington, University of........................................... 354
Washington State University ....................................... 355
Washington University ................................................ 356
Waterloo, University of .............................................. 378
Wayne State University .............................................. 357
West Virginia University ............................................ 358
Widener University ............................................ 378
Wisconsin, University of ............................................ 359
Worcester Polytechnic Institute ................................... 360
Wyoming, University of ............................................. 361
Yale University ..................... ....................... 362

Fall 1997

Graduate Education in Chemical Engineering

1if Faculty and Research Areas



Graduate assistant stipends
for teaching and research start at $7,500.

Industrially sponsored fellowships available
up to $17,000.

In addition to stipends,
tuition and fees are waived.

PhD students may get
some incentive scholarships.

The deadline for assistantship applications is
March 15th.

Digital Control, Mass Transfer, Multicomponent
Multiphase Processes. Heal Transfer, Interfacial
Colloids, Light Scattering Techniques
Catalysis, Reaction Engineering, Combustion, Environ-
mentally Benign Synthesis
Thermodynamics, Material Properties
Materials Processing and CVD Modeling
Fixed Bed Adsorption, Process Design
Fuel Technology, Process Engineering, Environmental
Biochemical Engineering, Environmental Biotechnology
Biochemical Engineering, Environmental Bioengineering
Fuel and Chemical Process Engineering, Reactive
Polymers, Waste Clean-Up
BioMateria Engineering and Polymer Engineering
Nonlinear Control, Chaotic Processes
Plastics Processing, Polymer Films, System Design

1 Professor Emeritus Adjunct Faculty Member

Cooperative Graduate Education Program is also available.

SFor Additional Information, Write *

Chairman, Graduate Committee
Department of Chemical Engineering The University of Akron Akron, OH 44325-3906

!68 Chemical Engineering Education

Chemical Engineering

at the




A dedicated faculty with state-of-the-art facilities
offer research programs leading to Master of
Science and Doctor of Philosophy degrees.

Research Interests:

Biomass Conversion, Catalysis and Reactor
Design, Energy Conversion Processes,
Environmental Studies, Interfacial Transport,
Magnetic Storage Media, Mass Transfer, Metal
Casting, Polymer Rheology, Process Dynamics
and Control, Reservoir Modeling, Suspension
and Slurry Rheology, Thermodynamics,
Transport Process Modeling

For Information Contact:
Director of Graduate Studies
Department of Chemical Engineering
The University of Alabama
Box 870203
Tuscaloosa, AL 35487-0203
An equal employ
Phone: (205) 348-6450 opportur
Fall 1997

ment/equal e
nity institution

G.C. April, Ph.D. (Louisiana State)
D. W. Arnold, Ph.D. (Purdue)
E. S. Carlson, Ph.D. (Wyoming)
P. E. Clark, Ph.D. (Oklahoma State)
W. C. Clements, Jr., Ph.D. (Vanderbilt)
R. W. Flumerfelt, Ph.D. (Northwestern)
R. A. Griffin, Ph.D. (Utah State)
I. A. Jefcoat, Ph.D. (Clemson)
P. W. Johnson, Ph.D. (New Mexico Tech.)
A. M. Lane, Ph.D. (Massachusetts)
M. D. McKinley, Ph.D. (Florida)
R. G. Reddy, Ph.D. (Utah)
L. Y. Sadler III, Ph.D. (Alabama)
V. N. Schrodt, Ph.D. (Penn. State)
n. J. M. Wiest, Ph.D. (Wisconsin)



The University of Alberta is well
known for its commitment to excel-
lence in teaching and research. The
Department of Chemical and Materi-
als Engineering has 34 professors and
over 100 graduate students. Degrees
are offered at the M.Sc. and Ph.D.
levels in Chemical Engineering, Ma-
terials Engineering, and Process
Control. All full-time graduate stu-
dents in the research programs re-
ceive a stipend to cover living ex-
penses and tuition.

For further information, contact
Graduate Program Officer WCM
Department of Chemical and Materials Engineering
University of Alberta
Edmonton, Alberta, Canada T6G 2G6
PHONE (403) 492-5805 FAX (403) 492-2881
e-mail: chemical. engineering@ualberta. ca

R.P. BATYCKY, Ph.D. (Massachusetts Inst. of Technology)
Transport Processes in Porous and Biological Media Fluid Mechanics
P. CHOI, Ph.D. (University of Waterloo)
Statistical Mechanics of Polymers Polymer Solutions and Blends
K. T. CHUANG, Ph.D. (University of Alberta)
Mass Transfer Catalysis Separation Processes Pollution Control
I. G. DALLA LANA, Ph.D. (Univ. of Minnesota) EMERITUS
Chemical Reaction Engineering Heterogeneous Catalysis
J.A.W. ELLIOTT, Ph.D. (University of Toronto)
Thermodynamics Statistical Thermodynamics Interfacial Phenomena
D. G. FISHER, Ph.D. (University of Michigan) EMERITUS
Process Dynamics and Control Real-Time Computer Applications
J.F. FORBES, Ph.D. (McMaster University)
Real-Time Optimization Control of Sheet Forming Processes
M. R. GRAY, Ph.D. (California Inst. of Tech.) DEAN OF GRADUATE STUDIES
Bioreactors Chemical Kinetics Bitumen Processing
M. GUAY, Ph.D. (Queens University)
Nonlinear Process Control Statistical Modeling Multivariate Statistics
R. E. HAYES, Ph.D. (University of Bath)
Numerical Analysis Reactor Modeling Computational Fluid Dynamics
B. HUANG, Ph.D. (University of Alberta)
Controller Performance Assessment Multivariable Control Statistics
S. M. KRESTA, Ph.D. (McMaster University)
Turbulent & Transitional Flows Multiphase Flows CFD
S. LIU, Ph.D. (University of Alberta)
Fluid-Particle Dynamics Transport Phenomena Mass Transfer
D. T. LYNCH, Ph.D. (University of Alberta) DEAN OF ENGINEERING
Catalysis Kinetic Modeling Numerical Methods Polymerization
J. H. MASLIYAH, Ph.D. (University of British Columbia)
Transport Phenomena Colloids Particle-Fluid Dynamics Oil Sands
A. E. MATHER, Ph.D. (University of Michigan)
Phase Equilibria Fluid Properties at High Pressures Thermodynamics
W. C. MCCAFFREY, Ph.D. (McGill University)
Reaction Kinetics Heavy Oil Upgrading Polymer Recycling Biotechnology
P. A. J. MEES, Ph.D. (University of Alberta)
Computational Fluid Dynamics Transport Phenomena Pulp and Paper
K. NANDAKUMAR, Ph.D. (Princeton University)
Transport Phenomena Distillation Computational Fluid Dynamics
F. D. OTTO, Ph.D. (University of Michigan) EMERITIS
Mass Transfer Gas-Liquid Reactions Separation Processes
M. RAO, Ph.D. (Rutgers University)
AI Intelligent Control Process Control
S. L. SHAH, Ph.D. (University of Alberta)
Computer Process Control System Identification Adaptive Control
S. E. WANKE, Ph.D. (University of California, Davis) CHAIR
Heterogeneous Catalysis Kinetics Polymerization
M. C. WILLIAMS, Ph.D. (University of Wisconsin)
Rheology Polymer Characterization Polymer Processing
Z. XU, Ph.D. (Virginia Polytechnic Institute and State University)
Surface Science & Engineering Mineral Processing Waste Management
Chemical Engineering Education


ROBERT ARNOLD, Professor (Caltech)
Microbiological Hazardous Waste Treatment, Metals Speciation and To.
JAMES BAYGENTS, Associate Professor (Princeton)
Fluid Mechanics, Transport and Colloidal Phenomena, Bioseparations,
MILAN BIER, Professor Emeritus (Fordham)
Protein Separation, Electrophoresis, Membrane Transport
WILLIAM P. COSART, Associate Professor and Associate Dean (Orego
Heat Transfer in Biological Systems, Blood Processing
JAMES FARRELL, Assistant Professor (Stanford)
Sorption/desorbtion of Organics in Soils
EDWARD FREEH, Adjunct Professor (Ohio State)
Process Control, Computer Applications
JOSEPH GROSS, Professor Emeritus (Purdue)
Boundary Layer Theory, Pharmacokinetics, Microcirculation, Biorheolh
ROBERTO GUZMAN, Associate Professor (North Carolina State)
Protein Separation, Affinity Methods
ARTHUR HUMPHREY, Visiting Professor (Columbia)
KIMBERLY OGDEN, Assistant Professor (Colorado)
Bioreactors, Bioremediation, Organics Removal from Soils
THOMAS W. PETERSON, Professor and Head (CalTech)
Aerosols, Hazardous Waste Incineration, Microcontamination
ALAN D. RANDOLPH, Professor Emeritus (Iowa State)
Crystallization Processes, Nucleation, Particulate Processes
THOMAS R. REHM, Professor Emeritus (Washington)
Mass Transfer, Process Instrumentation, Computer Aided Design
FARHANG SHADMAN, Professor (Berkeley)
Reaction Engineering, Kinetics, Catalysis, Reactive Membranes,
RAYMOND A. SIERKA, Professor (Oklahoma)
Adsorption, Oxidation, Membranes, Solar Catalyzed Detox Reactions
JOST 0. L. WENDT, Professor (Johns Hopkins)
Combustion-Generated Air Pollution, Incineration, Waste
DON H. WHITE, Professor Emeritus (Iowa State)
Polymers, Microbial and Enzymatic Processes
DAVID WOLF, Visiting Professor (Technion)
Fermentation, Mixing, Energy, Biomass Conversion
Associate Professor (UCLA)
High T Chemistry, Nanostructures, Chemical
Vapor Deposition

For further information, write to
Graduate Study Committee
Department of Chemical and
Environmental Engineering
University of Arizona
Tucson, Arizona 85721
The University of Arizona is an equal
opportunity educational institution/equal
opportunity employer.
Women and minorities are encouraged
to apply.

Fall 1997








The Chemical and Environmental Engineering Department
at the University of Arizona offers a wide range of research
opportunities in all major areas of chemical engineering and
environmental engineering, and graduate courses are offered in
most of the research areas listed here. The department offers a fully
accredited undergraduate degree as well as MS and PhD graduate
degrees. Strong interdisciplinary programs exist in bioprocessing
and bioseparations, microcontamination in electronics manu-
facture, and environmental process modification.
Financial support is available through fellowships, government
and industrial grants and contracts, teaching and
research assistantships.

Tucson has an excellent climate and many
recreational opportunities. It is a growing modern city of
450,000 that retains much of the old Southwestern atmosphere.





C r,46MCAL f4 *

1 "6 0CIA 44o"

310 ~* 0

*%0 CON*q0


0 0

Beaudoin, Stephen P., Ph.D., North Carolina State *
University Transport Phenomena and Surface Science 0 *
concerning Pollution Prevention, Waste Minimization, and a
Pollution Remediation *
Beckman, James R., Ph.D., University of Arizona Crystalli- *
zation and Solar Cooling
Bellamy, Lynn, Ph.D., Tulane Process Simulation *
Berman, Neil S., Ph.D., University of Texas, Austin Fluid
Dynamics and Air Pollution
Burrows, Veronica A., Ph.D., Princeton University Surface
Science, Semiconductor Processing
Cale, Timothy S., Ph.D., University of Houston Catalysis,
Semiconductor Processing
Garcia, Antonio A., Ph.D., U.C., Berkeley Acid-Base Interactions,
Biochemical Separation, Colloid Chemistry
Kuester, James L., Ph.D., Texas A&M University Thermochemical
Conversion, Complex Reaction Systems
Raupp, Gregory B., Ph.D., University of Wisconsin Semiconductor Materials
Processing, Surface Science, Catalysis
Rivera, Daniel, Ph.D., Cal Tech Process Control and Design
Sater, Vernon E., Ph.D., Illinois Institute of Tech Heavy Metal Removal from Waste
Water, Process Control
Torrest, Robert S., Ph.D., University of Minnesota Multiphase Flow, Filtration, Flow in
Porous Media, Pollution Control





Y *

Research in a
Research in a

High Technology


Dorson, William J., Ph.D., University of Cincinnati Physicochemical Phenomena, Transport Processes
Guilbeau, Eric J., Ph.D., Louisiana Tech University Biosensors, Physiological Systems, Biomaterials
He, Jiping, Ph.D., University of Maryland Biomechanics, Robotics, Computational Neuroscience, Optimal Control, System Dynamics and Control
Kipke, Daryl R., Ph.D., University of Michigan Computation Neuroscience Machine Vision, Speech Recognition, Robotics Neural Networks
Pizziconi, Vincent B., Ph.D. Arizona State University- Artificial Organs, Biomaterials, Bioseparations
Sweeney, James D., Ph.D., Case-Western Reserve University- Rehab Engineering, Applied Neural Control
Towe, Bruce C., Ph.D., Pennsylvania State University* Bioelectric Phenomena, Biosensors, Biomedical Imaging
Yamaguchi, Gary T., Ph.D., Stanford University Biomechanics, Rehab Engineering, Computer-Aided Surgery

Adams, James, Ph.D., University of Wisconsin, Madison Atomistic Simulation of Metallic Surfaces Grain Boundaries Automobile Catalysts *
Polymer-Metal Adhesion
Alford, Terry L., Ph.D., Cornell University Electronic Materials Physical Metallurgy Electronic Thin Films Surface/Thin Film
Carpenter, Ray W., Ph.D., University of California, Berkeley Atomic Structure and Chemistry of Interfaces and Boundaries in Solids; Phase
Transformation Mechanisms in Metals and Ceramics; Electron Microscopy Methods and Instrumentation
Dey, Sandwip K., Ph.D., NYSC of Ceramics, Alfred University Ceramics, Sol-Gel Processing
Krause, Stephen L., Ph.D., University of Michigan Ordered Polymers, Electronic Materials, Electron X-ray Diffraction, Electron Microscopy
Mahajan, Subhash, Ph.D., University of Michigan Semiconductor Defects, Structural Materials Deformation
Mayer, James, Ph.D., Purdue University -Thin Film Processing Ion Bean Modification of Materials
Stanley, James T., Ph.D., University of Illinois Phase Transformations, Corrosion

272 Chemical Engineering Education

* 'm


Robert P. Chambers University of California, Berkeley
Harry T. Cullinan Carnegie Mellon University
Christine W. Curtis Florida State University
Steve R. Duke University of Illinois
Mahmoud El-Halwagi University of California, Los Angeles
James A. Guin University of Texas, Austin
Ram B. Gupta University of Texas, Austin
Gopal A. Krishnagopalan University of Maine
Jay H. Lee California Institute of Technology
Y. Y. Lee Iowa State University
Glennon Maples Oklahoma State University
Ronald D. Neuman The Institute of Paper Chemistry
Stephen A. Perusich University of Illinois
Timothy D. Placek University of Kentucky
Christopher B. Roberts University of Notre Dame
A. R. Tarrer Purdue University
Bruce J. Tatarchuk University of Wisconsin

Research Areas

SBiochemical Engineering Biotechnology
Pulp and Paper Process Control
Catalysis and Reaction Engineering
Computer Aided Process Synthesis,
Optimization and Design
Environmental Chemical Engineering
Pollution Prevention Recycling
Materials Polymers Surface Science
Colloid and Interfacial Phenomena
Thermodynamics Supercritical Fluids
* Separation Electrochemical Engineering
* Fluid Dynamics and Transport Phenomena
Fuels and Energy

-' *v




R. G. Moore, Head (Alberta)
J. Azaiez (Stanford)
A. Badakhshan (Birmingham, U.K.)
L. A. Behie (Western Ontario)
C. Bellehumeur (McMaster)
P. R. Bishnoi (Alberta)
R. A. Heidemann (Washington U.)
C. Hyndman (Ecole Polytechnique)
A. A. Jeje (MIT)
A. Kantzias (Waterloo)
A. K. Mehrotra (Calgary)
B. J. Milne (Calgary)
M. Pooladi-Darvish (Alberta)
B. B. Pruden (McGill)
J. Stanislav (Prague)
W. Y. Svrcek (Alberta)
E. L. Tollefson (Toronto)
M. A. Trebble (Calgary)
H. W. Yarranton (Alberta)
L. Zanzotto (Slovak Tech. Univ., Czechoslovakia)

The Department offers graduate programs leading to the M.Sc. and Ph.D.
degrees in Chemical Engineering (full-time) and the M.Eng. degree in Chemical
Engineering, Petroleum Reservoir Engineering or Engineering for the
Environment (part-time) in the following areas:
Biochemical Engineering & Biotechnology
Biomedical Engineering
Environmental Engineering
Modeling, Simulation & Control
Petroleum Recovery & Reservoir Engineering
Process Development
Reaction Engineering/Kinetics
Transport Phenomena

Fellowships and Research Assistantships are available to all qualified applicants.


For Additional Information Write *
Dr. A. K. Mehrotra Chair, Graduate Studies Committee
Department of Chemical and Petroleum Engineering
The University of Calgary Calgary, Alberta, Canada T2N 1 N4

The University is located in the City of Calgary, the Oil capital of Canada, the home of the world famous Calgary Stampede and the
1988 Winter Olympics. The City combines the traditions of the Old West with the sophistication of a modem urban center. Beautiful
Banff National Park is 110 km west of the City and the ski resorts of Banff, Lake Louise,and Kananaskis areas are readily accessible. In
the above photo the University Campus is shown with the Olympic Oval and the student residences in the foreground. The Engineering
complex is on the left of the picture.



Chemical Engineering Education








. offers graduate programs leading to the
Master of Science and Doctor of Philosophy.
Both programs involve joint faculty-student
research as well as courses and seminars within
and outside the department. Students have the
opportunity to take part in the many cultural
offerings of the San Francisco Bay Area and
the recreational activities of California's north-
ern coast and mountains.

Biochemical Engineering
Electrochemical Engineering
Electronic Materials Processing
Energy Utilization
Fluid Mechanics
Kinetics and Catalysis
Polymer Science and Technology
Process Design and Development
Separation Processes
Surface and Colloid Science



















Fall 1997 275

University of California Davis

Department of Chemical Engineering & Materials Science
Offering M.S. and Ph.D. degree programs in both Chemical Engineering and Materials Science and Engineering


Nicholas L. Abbott, Associate Professor Ph.D., Massachusetts Institute of Technology, 1991 Nanostructured fluids, surfactants, molecular
assemblies, liquid crystals
David E. Block, Assistant Professor Ph.D., University of Minnesota, 1992 Industrialfermentation, biochemical processes in pharmaceutical
Roger B. Boulton, Professor Ph.D., University of Melbourne, 1976 Fermentation and reaction kinetics, crystallization
Stephanie R. Dungan, Associate Professor Ph.D., Massachusetts Institute of Technology, 1992 Micelle transport, colloid and interfacial
science infoodprocessing
Bruce C. Gates, Professor Ph.D., University of Washington, Seattle, 1966 Catalysis, solid superacid catalysis, zeolite catalysts, bimetallic
catalysts, catalysis by metal clusters
Jeffery C. Gibeling, Professor Ph.D., Stanford University, 1979 Deformation and fatigue of metals and metal matrix composites
Joanna R. Groza, Professor Ph.D., Polytechnic Institute, Bucharest, 1972 Plasma activated sintering and processing of nanostructured
Brian G. Higgins, Professor Ph.D., University of Minnesota, 1980 Fluid mechanics and interfacial phenomena, sol gel processing, coating flows
David G. Howitt, Professor* Ph.D., University of California, Berkeley, 1976 Forensic and failure analysis, electron microscopy, ignition and
combustion processes in materials
Alan P. Jackman, Professor Ph.D., University of Minnesota, 1968 Protein production in plant cell cultures, bioremediation
Marjorie L. Longo, Assistant Professor Ph.D., University of California, Santa Barbara, 1993 Hydrophobic protein design for active control,
surfactant microstructure, and interaction of proteins and DNA with biological membranes
Benjamin J. McCoy, Professor Ph.D., University of Minnesota, 1967 Supercritical extraction, pollutant transport
Karen A. McDonald, Associate Professor Ph.D., University of Maryland, College Park, 1985 Plant cell culture bioprocessing algal cell cultures
Amiya K. Mukherjee, Professor D.Phil., University of Oxford, 1962 Superplasticity of intermetallic alloys and ceramics, high temperature
creep deformation
Zuhair A. Munir, Professor Ph.D., University of California, Berkeley, 1963 Combustion synthesis, multilayer combustion systems, functionally
gradient materials
Alexandra Navrotsky, Professor Ph.D., University of Chicago, 1967 Thermodynamics and solid state chemistry; high temperature calorimetnr
Ahmet N. Palazoglu, Professor Ph.D., Rensselaer Polytechnic Institute, 1984 Process control and process design of environmentally benign
Ronald J. Phillips, Associate Professor Ph.D., Massachusetts Institute of Technology, 1989 Transport processes in bioseparations, Newtonian
and non-Newtonian suspension mechanics
Robert L. Powell, Professor Ph.D., Johns Hopkins University, 1978 Rheology, suspension mechanics, magnetic resonance imaging of
Subhash H. Risbud, Professor and Chair Ph.D., University of California, Berkeley, 1976 Semiconductor quantum dots, high T, superconducting
ceramics, polymer compositesfor optics
Dewey D.Y. Ryu, Professor Ph.D., Massachusetts Institute of Technology, 1967* Biomolecularprocess engineering and recombinant bioprocess
James F. Shackelford, Professor Ph.D., University of California, Berkeley, 1971 Structure of materials, biomaterials, nondestructive testing of
engineering materials
J.M. Smith, Professor Emeritus Sc.D., Massachusetts Institute of Technology, 1943 Chemical kinetics and reactor design
Pieter Stroeve, Professor Sc.D., Massachusetts Institute of Technology, 1973 Membrane separations, Langmuir Blodgett films, colloid and
surface science
Stephen Whitaker, Professor Ph.D., University of Delaware, 1959* Multiphase transport phenomena

Sacmento: 17 miles
San Fancsco. 72 miles
LkL Tahoe: 90 miles

Davis is a small, bike-friendly university town
located 17 miles west of Sacramento and 72 miles
northeast of San Francisco, within driving dis-
tance of a multitude of recreational activities in
Yosemite, Lake Tahoe, Monterey, and San Fran-
cisco Bay Area.

For information about our program, look up our web
site at
or contact us via e-mail at
On-line applications may be submitted via

Graduate Admission Chair
Professor Ronald J. Phillips
Department of Chemical Engineering & Materials Science
University of California, Davis
Davis, CA 95616-5294, USA
Phone 1916) 752-2803 Fax (916) 752-1031

Chemical Engineering Education

The multifaceted graduate study experience in the Department
of Chemical Engineering and Materials Science allows students to
choose research projects and thesis advisors from any of our faculty
with expertise in chemical engineering and/or materials science and
Our department faculty provide excellent access to the scientists
and facilities at nearby National Laboratories (LBL and LLNL) and
industry in the Silicon Valley and San Francisco Bay Area.




Offers degrees at the M.S. and Ph.D.
levels. Research in frontier areas in
chemical engineering, biochemical en-
gineering, biotechnology and materials
science and engineering. Strong physi-
cal and life science and engineering
groups on campus.

The 1,510-acre UC Irvine campus is in
Orange County, five miles from the Pa-
cific Ocean and 40 miles south of Los
Angeles. Irvine is one of the nation's
fastest growing residential, industrial,
and business areas. Nearby beaches,
mountain and desert area recreational
activities, and local cultural activities
make Irvine a pleasant city in which to
live and study.

For further information and
application forms, please visit
or contact
Department of Chemical and Biochemical
Engineering and Materials Science
School of Engineering
University of California
Irvine, CA 92697-2575

Graduate Studies in

Chemical and Biochemical Engineering
Materials Science and Engineering

for Chemical Engineering, Engineering, and Science Majors


Nancy A. Da Silva (California Institute of Technology)
James C. Earthman (Stanford University)
Steven C. George (University of Washington)
Juan Hong (Purdue University)
Enrique J. Lavernia(Massachusetts Institute of Technology)
Henry C. Lim (Northwestern University)
Martha L. Mecartney (Stanford University)
Farghalli A. Mohamed (University of California, Berkeley)
Frank G. Shi (California Institute of Technology)
Thomas K. Wood (North Carolina State University)

Joint Appointments:
Roger H. Rangel (University of California, Berkeley)
William A. Sirignano (Princeton University)


* Biomedical Engineering
* Bioreactor Engineering
* Bioremediation
* Ceramics
* Combustion
* Composite Materials
* Control and Optimization
* Environmental Engineering
* Interfacial Engineering
* Materials Processing
* Mechanical Properties
* Metabolic Engineering

Fall 1997

* Microelectronics Processing and
* Microstructure of Materials
* Nanocrystalline Materials
* Nucleation, Chrystallization and
Glass Transition Process
* Polymers
* Recombinant Cell Technology
* Separation Processes
* Sol-Gel Processing
* Two-Phase Flow
* Water Pollution Control





* Molecular Simulations
* Thermodynamics and
* Process Design, Dynamics, and
* Polymer Processing and Transport
* Kinetics, Combustion, and
* Surface and Interface Engineering
* Electrochemistry and Corrosion
* Biochemical Engineering
* Aerosol Science and
* Air Pollution Control and Environ-
mental Engineering

Panagiotis D. Christofides
Y. Cohen
M. W. Deem
T. H. K. Frederking
S. K. Friedlander
R. F. Hicks
E. L. Knuth
(Prof Emeritus)
James C. Liao
V. Manousiouthakis
H. G. Monbouquette
K. Nobe
L. B. Robinson
(Prof Emeritus)
S. M. Senkan
W. D. Van Vorst
(Prof. Emeritus)
V. L. Vilker
(Prof Emeritus)
A. R. Wazzan


UCLA's Chemical Engineering Department offers a pro-
gram of teaching and research linking fundamental engineer-
ing science and industrial practice. Our Department has strong
graduate research programs in environmental chemical engi-
neering, biotechnology, and materials processing. With the
support of the Parsons Foundation, The National Science
Foundation, and the U.S. Department of Education, we are
pioneering the development of methods for the design of
clean chemical technologies, both in graduate research and

engineering education.
Fellowships are available for outstanding applicants in
both M.S. and Ph.D. degree programs. A fellowship in-
cludes a waiver of tuition and fees plus a stipend.
Located five miles from the Pacific Coast, UCLA's
attractive 417-acre campus extends from Bel Air to
Westwood Village. Students have access to the highly
regarded science programs and to a variety of experiences
in theatre, music, art, and sports on campus.


Adisin7OfceR Chemical Engineering Educationt
55~T~~31 Boelter Hall UCLA -, Los Angeles, CA 90095-1592~;l ~ L~
~~,~r~(310) 825-9063

Chemical Engineering Education




L. GARY LEAL Ph.D. (Stanford) (Chair) Fluid Mechanics, Physics and Rheology of Complex Fluids, including Polymers, Suspensions, and
ERAY S. AYDIL Ph.D. (University of Houston) Microelectronics and Plasma Processing.
SANJOY BANERJEE Ph.D. (Waterloo) Environmental Fluid Dynamics, Multiphase Flows, Turbulence, Computational Fluid Dynamics.
BRADLEY F. CHMELKA Ph.D. (U.C. Berkeley) Inorganic-Organic Hybrid Materials, Zeolites and Molecular Sieves, Polymeric Solids, Liquid
Crystals, Solid-State NMR.
GLENN H. FREDRICKSON Ph.D. (Stanford) (Vice-Chair) Statistical Mechanics, Glasses, Polymers, Composites, Alloys.
JACOB ISRAELACHVILI Ph.D. (Cambridge) Surface and Interfacial Phenomena, Adhesion, Colloidal Systems, Surface Forces, Biomolecular
Interactions, Friction.
EDWARD J. KRAMER Ph.D. (Carnegie-Mellon) Microscopic Fundamentals of Fracture of Polymers, Diffusion in Polymers, Polymer
Surfaces and Interfaces.
FRED F. LANGE Ph.D. (Penn State) Powder Processing of Composite Ceramics, Liquid Precursors for Ceramics, Superconducting Oxides.
GLENN E. LUCAS Ph.D. (M.I.T.) Mechanics of Materials, Structural Reliability.
DIMITRIOS MAROUDAS Ph.D. (M.I.T.) Theoretical and Computational Materials Science, Microstructure Evolution in Electronic and
Structural Materials.
ERIC McFARLAND Ph.D. (M.I.T.) M.D. (Harvard) Biomedical Engineering, NMR and Neutron Imaging, Transport Phenomena in Complex
Liquids, Radiation Interactions.
DUNCAN A. MELLICHAMP Ph.D. (Purdue) Computer Control. Process Dynamics, Real-Time Computing.
PHILIP A. PINCUS Ph.D. (U.C. Berkeley) Theory of Surfactant Aggregates, Colloid Systems.
DAVID J. PINE Ph.D. (Cornell) Polymer, Surfactant, and Colloidal Physics, Multiple Light Scattering, Photonic Crystals, Macroporous
ORVILLE C. SANDALL Ph.D. (U.C. Berkeley) Transport Phenomena, Separation Processes.
DALE E. SEBORG Ph.D. (Princeton) Process Control, Monitoring and Identification.
T. G. THEOFANOUS Ph.D. (Minnesota) Multiphase Flow, Risk Assessment and Management
W. HENRY WEINBERG Ph.D. (U.C. Berkeley) Surface Chemistry, Heterogeneous Catalysis, Electronic Materials, Materials Discovery
using Combinatorial Chemistry
JOSEPH A. ZASADZINSKI Ph.D. (Minnesota) Surface and Interfacial Phenomena, Biomaterials.

The Department offers M.S. and
Ph.D. degree programs Finan-
cial aid, including fellowships,
teaching assistantships, and re-
search assistantships, is avail-
One of the world's few seashore
campuses, UCSB is located on
the Pacific Coast 100 miles
northwest of Los Angeles. The
student enrollment is over
18,000. The metropolitan Santa
Barbara area has over 150,000
residents and is famous for its
mild, even climate.
For additional information
and applications, write to
Chair Graduate Admissions Committee Department of Chemical Engineering University of California Santa Barbara, CA 93106
Fall 1997 279

Chemical Engineering at the





"At the Leading Edge"

Frances H. Arnold
John F. Brady
Mark E. Davis
Richard C. Flagan

George R. Gavalas
Konstantinos P. Giapis
Julia A. Kornfield
John H. Seinfeld

David A. Tirrell
Nicholas W. Tschoegl
Zhen-Gang Wang

Aerosol Science
Applied Mathematics
Atmospheric Chemistry and Physics
Biocatalysis and Bioreactor Engineering
Chemical Vapor Deposition

Colloid Physics
Fluid Mechanics
Materials Processing
Microelectronics Processing
Microstructured Fluids
Polymer Science
Protein Engineering
Statistical Mechanics

For further information, write
Director of Graduate Studies
Chemical Engineering 210-41 California Institute of Technology Pasadena, California 91125
Also, visit us on the World Wide Web for an on-line brochure:

Chemical Engineering Education


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M.S. and Ph.D. Programs in Chemical Engineering


John Angus
Colman Brosilow
Robert Edwards
Donald Feke
Nelson Gardner
Howard Greene
Uziel Landau
Chung-Chiun Liu
J. Adin Mann
Philip Morrison
Syed Qutubuddin
Robert Savinell

Research Opportunities

* Low Pressure Growth of Diamonds
* Process Control
* Colloidal Phenomena and Microemulsions
* Electrochemical Engineering
* Biomedical Sensors
* Synthesis of Electronic Material
* Polymers and Interfacial Phenomena
* Fuel Cells
* Catalysis and Reactor Design
* Separation Processes
* Interfacial Transport and Liquid Crystals
* In Situ Diagnostics

For more information on
Graduate Research,
Admission, and Financial Aid,

Graduate Coordinator
Department of
Chemical Engineering
Case Western Reserve University
10900 Euclid Avenue
Cleveland, Ohio 44106-7217

or see our home page at


Chemical Engineering Education

Students in the Department of Chemical Engineering are involved in state-of-the-art re-
search. Here, two students make adjustments to a component of a prototype fuel cell

Opportunities for Graduate Study in Chemical Engineering at the

M.S. and Ph.D. Degrees in Chemical Engineering


Amy Ciric

Joel Fried

Stevin Gehrke

Rakesh Govind

David Greenberg

Daniel Hershey

Sun-Tak Hwang

Robert Jenkins

Yuen-Koh Kao

Soon-Jai Khang

Y. S. Lin

Neville Pinto

Sotiris Pratsinis

Peter Smirniotis


The University of Cincinnati is
committed to a policy of
awarding financial aid.

For Admission Information
Director, Graduate Studies
Department of Chemical Engineering
PO Box 210171
University of Cincinnati
Cincinnati, Ohio 45221-0171
Fall 1997

The faculty and students in the Department of Chemical Engineering are engaged in a diverse
range of exciting research topics. A limited number of assistantships and tuition scholarships are
available to highly qualified applicants to the MS and PhD degree programs.

O Biotechnology (Bioseparations)
Novel bioseparation techniques, chromatography, affinity separations, biodegradation of
toxic wastes, controlled drug delivery, two-phase flow, suspension rheology.
E Chemical Reaction Engineering and Heterogeneous Catalysis
Modeling and design of chemical reactors, deactivation of catalysts, flow pattern and
mixing in chemical equipment, laser induced effects.

l Coal Research
New technology for coal combustion power plant, desulfurization and denitritication.

D Material Synthesis
Manufacture of advanced ceramics, opticalfibers and pigments by aerosol processes.
E Membrane Separations
Membrane gas separations, membrane reactors, sensors and probes, pervaporation,
dynamic simulation of membrane separators, membrane preparation and characteriza-
tion for polymeric and inorganic materials, inorganic membranes.
E Particle Technology
Flocculation of liquid suspensions, granulation of fine powders, grinding of agglomerate
E Polymers
Thermodynamics, polymer blends and composites, high-temperature polymers,
hydrogels, rheology, computational polymer science.
E Process Synthesis
Computer-aided design methodologies, design for waste minimization, design fbr
dynamic stability, separation system synthesis.

Graduate Study in

Chemical Engineering



M.S., M.ENG., and PH.D.
Teaching and Research
Assistantships available to
M.S. and Ph.D. students

Research Areas:
> Electrochemical Engineering
10 Chemical Kinetics
0 Chemical Metallurgy
> Corrosion Engineering
O Crystal Growth
0 Space Processing
Process Control For information, write to:
2 Fluid Mechanics Dr. Anthony G. Collins
> Bubble Dynamics Dean of Engineering
O Heat Transfer Clarkson University
O Mass Transfer P.O. Box 5700
> Laser and Plasma Technology Potsdam, New York 13699-5700
Oo Polymer Processing and Rheology 315-268-7929
O Biochemical Engineering Fax: 315-268-3841
> Process Design Email:
> Solid State Reactions World Wide Web:
Clarkson University is a nondiscriminatory, affirmative action, equal opportunity educator and employer.
284 Chemical Engineering Education

Graduate Study in Chemical Engineering at


Tradition and Excellence Meet

For more than 100 years, engineering at Clemson University has distinguished itself by pursuing excel-
lence through the combination of traditional education and innovative research programs. The Depart-
ment of Chemical Engineering has continued in that vein by building very active research programs
aimed at developing basic scientific understanding of critical engineering materials and technology. Ad-
ditionally, students can participate in the department's M.S. Industrial Residency Program, which com-
bines on-campus course work with practical work assignments in industry. Students can conduct their
thesis research under joint faculty and industrial supervision.
Clemson is a land-grant institution with an enrollment of more than 16,500 students, including 3,800
graduate students. The 1,400-acre main campus is located in the foothills of the Blue Ridge Mountains,
on the shores of Lake Hartwell, midway between Atlanta, Ga., and Charlotte, N.C.

The Faculty

Research Areas

Charles H. Barron, Jr.
David A. Bruce
Dan D. Edie
Charles H. Gooding
James M. Haile
Douglas E. Hirt

S. Michael Kilbey II
Stephen S. Melsheimer
Amod A. Ogale
Richard W. Rice
Mark C. Thies

* Catalysis Molecular Dynamics
* Engineering Polymers &
Fibers & Films Composites
* Interfacial Engineering Supercritical Fluids
* Membrane Separations Water Remediation
Programs lead to the M.S. and Ph.D. degrees.

For More Information, Contact: Graduate Coordinator, Department of Chemical Engineering, Clemson University,
Box 340909, Clemson, SC 29634-0909, Telephone (864) 656-3055, Email address:
Visit our Web site at


Assistant Professor
Polymers, Biomaterials BOULDER
Assistant Professor > Graduate students in the Department of
Biomechanics, Biomedical Engineering, Fluid Mechanics Chemical Engineering may also participate in the
CHRISTOPHER N. BOWMAN popular interdisciplinary Biotechnology Training Program
Associate Professor at the University
Polymers, Membrane Materials of Colorado and
DAVID E. CLOUGH in the inter-
Professor disciplinary
Process Control, Water Resources NSF Industry/
ROBERT H. DAVIS F University
Patten Professor and Chair Cooperative
Fluid Mechanics, Biotechnology, Membranes Research Center
JOHN L. FALCONER for Separations
Professor Using Thin
Catalysis, Zeolite Membranes Films.

Associate Professor
Associate Professor
Bioprocess Engineering, Animal Cell Cultures
Professor and President's Teaching Scholar,
Membranes, Geophysics, Global Change
Membranes, Separations
Process Control, Biotechnology
Associate Professor
Biotechnology, Supercritical Fluids
Transport Phenomena, Applied Mathematics
Research Professor
Biotechnology, Bioseparations
Ceramic Materials, Reaction Engineering

Biotechnology and Bioengineering
Biomaterials and Biomechanics
Biomedical Engineering
Bioreactor Design and Optimization
Purification and Formulation
Chemical Environmental Engineering
Global Change
Pollution Remediation
Materials Science and Engineering
Catalysis and Surface Science
Advanced Ceramics Synthesis
Colloidal Phenomena
Polymerization Reaction Engineering
Membrane Science
Chemically Specific Separations
Membrane Transport and Separations
Polymeric Membrane Morphology
Modeling and Control
Expert Systems
Mathematical Modeling
Process Control and Identification
Transport Phenomena and Thermodynamics
Fluid Dynamics
Suspensions and Complex Fluids
Supercritical Fluids

Graduate Admissions Committee Department of Chemical Engineering
University of Colorado, Boulder Boulder, Colorado 80309-0424
'HONE (303) 492-7471 FAX (303) 492-4341 E-MAIL

Further information is also available on our URL page on the World Wide Web at

Chemical Engineering Education






R. M. BALDWIN, Professor and Head; Ph.D., Colorado School of Mines. Fuels science and catalysis.
A. L. BUNGE, Professor; Ph.D., University of California, Berkeley. Absorption of chemicals in skin, phannacokinetic modeling, risk assessment.
J.R. DORGAN, Associate Professor; Ph.D., University of California, Berkeley. Polymer science and engineering.
J. F. ELY, Professor; Ph.D., Indiana University. Molecular thermodynamics and transport properties offluids.
J. H. GARY, Professor Emeritus: Ph.D., University of Florida. Petroleum refinery processing operations, heavy oil processing, thermal cracking, vishreaking and
solvent extraction.
J.O. GOLDEN, Professor; Ph.D., Iowa State University. Hazardous waste processing, fluidization engineering, incineration.
M.S. GRABOSKI, Research Professor; Ph.D., Pennsylvania State University. Fuels synthesis and evaluation, engine technology, alternate fuels
A. J. KIDNAY, Professor and Graduate Dean; D.Sc., Colorado School of Mines. Thermodynamic properties of gases and liquids, vapor-liquid equilibria, cryogenic
D.W.M. MARR, Assistant Professor; Ph.D., Stanford. Interfacial statistical mechanics, complexfluids.
R.L. McCORMICK, Research Assistant Professor; Ph.D., Wyoming. Catalysis in fuel synthesis, air pollution control, fuel cells, low emissions fuels for internal
combustion engines, coal science and processing, ion conducting solid catalysts and electrolytes, reactor design and fluidization.
J.T. McKINNON, Associate Professor; Ph.D., Massachusetts Institute of Technology. High temperature gas phase chemical kinetics, combustion, hazardous waste
R. L. MILLER, Associate Professor; Ph.D., Colorado School of Mines. Interdisciplinary curriculum development, innovative pedagogies, measures of intellectual
development, psychological theories of learning, multiphase fluid mechanics
M. S. SELIM, Professor; Ph.D., Iowa State University. Heat and mass transfer with a moving boundary, sedimentation and diffusion of colloidal suspensions, heat
effects in gas absorption with chemical reaction, entrance region flow and heat transfer, gas hydrate dissociation modeling, sweetening of natural gas using mixed
amines, inkjet printing, synthesis of nano-size magnetic particles for color toner and laserjet printing applications, modeling of hydrocarbon cracking furnaces
and simulation of ethylene plants.
E. D. SLOAN, JR., Weaver Distinguished Professor; Ph.D. Clemson University. Natural gas hydrates, phase equilibria, education methods research.
J. D. WAY, Associate Professor; Ph.D. University of Colorado. Novel separation processes, membrane science and technology, membrane reactors, ceramic and
metal membranes, biopolymer adsorbentsfor adsorption of heavy metals.
C. A. WOLDEN, Assistant Professor, Ph.D., Massachusetts Institute of Technology. Electronic materials processing, gas-solid reaction dynamics.
D. T. WU, Assistant Professor; Ph.D. University of California, Berkeley. Polymers, powders, theory and simulation of complex fluids and materials, phase equilibria,
controlled self-assembly.
V. F. YESAVAGE, Professor; Ph.D., University of Michigan. Vapor liquid equilibrium and enthalpy ofpolar associating fluids, equations of state for highly non-ideal
systems, process simulation, environmental engineering, gas-liquid reactions.

Fall 1997 287


tate University

CSU is located in Fort Collins, a pleasant commu-
nity of 100,000 people with the spirit of the West, the
vitality of a growing metropolitan area, and the
friendliness of a small town. Fort Collins is located
about 65 miles north of Denver and is adjacent to
the foothills of the Rocky Mountains. The climate is
excellent, with 300 sunny days per year, mild tem-
Speratures, and low humidity. Opportunities for hik-
ing, biking, camping, boating, fishing, and skiing
abound in the immediate and nearby areas. The
campus is within easy walking or biking distance of
the town's shopping areas and its Center for the
Performing Arts.

M.S. and Ph.D. programs in FACULTY

chemical engineering Laurence A. Belfiore, Ph.D.
University of Wisconsin
RESEARCH IN... David S. Dandy, Ph.D.
SAdvanced Process Control Caliornia Institute oTechnology
i ial Engineering Deanna S. Durnford, Ph.D.
SBiochemicral Engineering Colorado State University
Biofuels VM. Nazmul Karim, Ph.D.
Catalysis University of Manchester
Chemical Thermodynamics Terry G. Lenz, Ph.D.
Chemical Vapor Deposition Iowa State University
Contaminant Transport James C. Linden, Ph.D.
IoWa State University
Computational Fluid Dynamics
Jim C. Loftis, Ph.D.
Environmental Biotechnology Colorado State University
o Environmental Engineering Carol M. McConica, Ph.D.
Polymeric Materials Stanford University
Solar Cooling Systems David B. McWhorter, Ph.D.
Semiconductor Processing Colorado State University
0 Thin Films Vincent G. Murphy, Ph.D.
IN- Water Quality Monitoring University of Massachusetts
Allen L. Rakow, Sc.D.
Kenneth F. Reardon, Ph.D.
Teaching and research assistantships paying a California Institute of Technology
monthly stipend plus tuition reimbursement.

For applications and further information, write
Department of Chemical and Bioresource Engineering
Colorado State University
Fort Collins, CO 80523-1370

Chemical Engineering Education

KoDert C. wara, hn.L.
North Carolina State University
Ranil Wickramasinghe, Ph.D.
University of Minnesota



Graduate Study in
Chemical Engineering

Graduate Admission,
191 Auditorium Road, U-122
University of Connecticut
Storrs, CT 06269-3222
Tel. (203) 486-4020
Fall 1997

M.S. and Ph.D. Programs for Scientists and Engineers

Luke E.K. Achenie, Ph.D., Carnegie Mellon University
Modeling and Optimization, Neural Networks, Process Control
Thomas F. Anderson, Ph.D., University of California, Berkeley
Modeling of Separation Processes, Fluid-Phase Equilibria
James P. Bell, Sc.D., Massachusetts Institute of Technology
Structure-Property Relations in Polymers and Composites, Adhesion
Carroll O. Bennett, Professor Emeritus, PhD., Yale University
Catalysis, Chemical Reaction Engineering
Douglas J. Cooper, Ph.D., University of Colorado
Process Modelinbg, Monitoring and Control
Robert W. Coughlin, Ph.D., Cornell University
Biotechnology, Biochemical and Environmental Engineering, Catalysis, Kinetics, Separations,
Surface Science
Michael B. Cutlip, Ph.D., University of Colorado
Kinetics and Catalysis, Electrochemical Reaction Engineering, Numerical Methods
Anthony T. DiBenedetto, University Professor Emeritus, Ph.D., University of
Composite Materials, Mechanical Properties of Polymers
Can Erkey, Ph.D., Texas A&M University
Supercritical Fluids, Environmental Engineering, Multicomponent Diffusion and Mass Transfer
James M. Fenton, Ph.D., University of Illinois, Urbana-Champaign
Electrochemical and Environmental Engineering, Mass Transfer Processes, Electronic Mate-
rials, Energy Systems
Suzanne (Schadel) Fenton, Ph.D., University of Illinois
Computational Fluid Dynamics, Turbulence, Two-Phase Flow
Robert J. Fisher, Ph.D., University of Delaware
Biochemical Engineering and Environmental Biotechnology
Joseph J. Helble, Ph.D., Massachusetts Institute of Technology
Air Pollution, Nanoscale Materials Synthesis and Characterization, Combustion
G. Michael Howard, Professor Emeritus, Ph.D., University of Connecticut
Process Systems Analysis and Modeling, Process Safety, Engineering Education
Herbert E. Klei, Professor Emeritus, Ph.D., University of Connecticut
Biochemical Engineering, Environmental Engineering
Jeffrey T. Koberstein, Ph.D., University of Massachusetts
Polymer Blends/Compatibilization, Polymer Morphology, Polymer Surface and Interfaces
Harold R. Kunz, Ph.D., Rensselaer Polytechnic Institute
Fuel Cells, Electrochemical Energy Systems
Montgomery T. Shaw, Ph.D., Princeton University
Polymer Rheology and Processing, Polymer-solution Thermodynamics
Donald W. Sundstrom, Professor Emeritus, Ph.D., University of Michigan
Environmental Engineering, Hazardous Wastes, Biochemical Engineering
Robert A. Weiss, Ph.D., University of Massachusetts
Polymer Structure-Property Relationships, Ion-Containing and Liquid Crystal Polymers, Poly-
mer Blends

At Cornell University, graduate students in chemical engineering have the flexibility to
design research programs that take full advantage of Corell's unique interdisciplinary
environment and enable them to pursue individualized plans of study.
Cornell graduate programs may draw upon the resources of many excellent depart-
ments and NSF-sponsored research centers such as the Biotechnology Center, the Cornell
National Supercomputing Facility, and the Materials Science Center.
Degrees granted include Master of Engineering, Master of Science, and Doctor of
Philosophy. All Ph.D. students are fully funded with attractive stipends and tuition

Research Areas
* Advanced Materials Processing
* Biochemical and Biomedical Engineering
* Fluid Dynamics, Stability, and Rheology
* Molecular Thermodynamics and
Computer Simulation
* Polymer Science and Engineering
* Reaction Engineering: Surface Science,
Kinetics, and Reactor Design

Situated in the scenic Finger Lakes region of
New York State, the Cornell campus is one of
the most beautiful in the country. Students
enjoy sailing, skiing, fishing, hiking, bicycling,
boating, wine-tasting, and many other

Distinguished Faculty
A. Brad Anton
Paulette Clancy
Claude Cohen
T. Michael Duncan
James R. Engstrom*
Emmanuel P. Giannelis
Keith E. Gubbinst
Peter Harriott
Donald L. Koch*
Kelvin H. Lee
Leonard W. Lion
Christopher K. Ober
William L. Olbricht
Athanassios Panagiotopoulos*
Ferdinand Rodriguez
W. Mark Saltzman
Michael L. Shulert,
Paul H. Steen
* recipient, NSF PYI Award
f member, National Academy of Engineering
* member, American Academy of
Arts & Science

Chemical Engineering Education

For further information, write:
Graduate Field Representative, School of Chemical Engineering, Cornell University, 120 Olin Hall, Ithaca, NY 14853-5201,
e-mail: GFR@CHEME.CORNELL.EDU, or "visit" our World Wide Web server at:


Mark A. Barteau
Antony N. Beris
Kenneth B. Bischoff
Douglas J. Buttrey
Stuart L. Cooper
Nily R. Dan
Costel D. DDenson
Prasad S. Dhurjati
Francis J. Doyle III
Henry C. Foley
Marylin C. Huff
Eric W. Kaler
Michael T. Klein
Abraham M. Lenhoff
Raul F. Lobo
Roy L. McCullough
Arthur B. Metzner, Emeritus
Jon H. Olson
Anne Skaja Robinson
T.W. Fraser Russell
Stanley I. Sander
Jerold M. Schultz
Annette D. Shine
Norman J. Wagner
Richard P. Wool
Andrew L. Zydney

Research Areas
Thermodynamics Separation Processes *
Polymer Science and Engineering *
Fluid Mechanics and Rheology *
STransport Phenomena Materials Science
and Metallurgy Catalysis and Surface
Science Reaction Kinetics Reactor
Engineering Process Control *
Semiconductor and Photovoltaic
Processing Biomedical Engineering
Biochemical Engineering *
Colloid and Surfactant Science

University of


The University of Delaware offers
M.ChE and Ph.D. degrees in
Chemical Engineering.
Both degrees involve
research and course work
in engineering and related sciences.

The Delaware tradition
is one of strong
interdisciplinary research
both fundamental
and applied problems.

For more information and application materials, write
Graduate Advisor Department of Chemical Engineering
University of Delaware Newark, Deleware 19716

Fall 1997 29







Chemical Engineering

Graduate Study
Leading to the MS and PhD

TIM ANDERSON Semiconductor Processing, Thermodynamics
IOANNIS BITSANIS Molecular Modeling of Interfaces
OSCAR D. CRISALLE Electronic Materials, Process Control
RICHARD B. DICKINSON Biomedical Engineering
ARTHUR L. FRICKE Polymers, Pulp & Paper Characterization
GAR HOFLUND Catalysis, Surface Science
LEW JOHNS Applied Mathematics, Dispersion
DALE KIRMSE Computer Aided Design, Process Control
RANGA NARAYANAN Transport Phenomena, Low Gravity Fluid Mechanics
MARK E. ORAZEM Electrochemical Engineering, Semiconductor Processing
CHANG-WON PARK Fluid Mechanics, Polymer Processing
RAJ RAJAGOPALAN Colloid Physics, Particle Science
DINESH 0. SHAH Surface Sciences, Biomedical Engineering
SPYROS SVORONOS Process Control, Biochemical Engineering

For more information, please write:
Graduate Admissions Coordinator U Department of Chemical Engineering
University of Florida U P.O. Box 116005 E Gainesville, Florida 32611-6005
Phone (352) 392-0881 E-mail, Website,
292 Chemical Engineering Education

le search and radiattStmdies in themical engineering
Florida AM University/ Flrido-tatoe Uaiversity Colege offngineering
SlS. andPh. Prog rams

fa jtq i
R_$o Aihmo
tense voiversity of Madrid
| fe Arce
I VRfiAersity
SR i don Chella
V iersity of Massachusetts
S Wright Finney
4lorida State University
Stephen J. Gibbs
University of Wisconsin
Eric Kalu
Texas A&M University
Bruce R. Locke
North Carolina State University
Srinivas Palanki
University of Michigan
Michael H. Peters,
Ohio State University
Samuel Riccardi J
Ohio State Univs
John C. Ti
University a^ i
Jorgwe!ials l
Univeir elona
I-aOW te University -Qi
^""f~r informa t:t4
"^D director of uiJ||m
SDeparkgie C cql E


facrtu researirchintersts
Advanced Materials
Composite matlals ond-ceramics
Dynamics of polymer blends and solutioniunded w
Fluid mechanics of ixingo-A
Polymer eystalli~Ai W ,-"
Bio-engieeringo F
Aerosol drug delivery- ems X%
Dynamics and transport of biological macromolecules
Electrophoretic separation of biological molecule^
Fermentation ocess
Lung contamiil ,_
Microhemo ics ki
-- :^ : Transport in biological t
u. c ess- Control and Optimizati
--s-_ o r Nonlinear processl ntr
4L J Optimization of batch rea.-
e a Mce and Engein-
_C at orono reaction e eii ng
Sc Electrochemical en gl
4 J l reaction and the amics
STranspor ocesses
i r and macromble I transport
"J- ,^ Multi-phasos and reaction
il^ ,.- NMR imaging
motion, trA and deposition
SN ly ics, pattern-formation and chaos
.r ort ai ion in porous media
Suspension rheology
ote research Programs
S Geodr ical Fluids Dynamics Institute
.j a~if rstitute for Molecular Biophysics
SMatals Research and Technology Center
i lptional High Magnetic Field Laboratory
9- Sup mputer Computations Research Institute

_ -*


P.A. Jennings, Ph.D.
D.R. Mason, Ph.D.
M.E. Pozo de Fernandez, Ph.D.
M.R. Shaffer, Ph.D.
M.M. Tomadakis, Ph.D.
J.E. Whitlow, Ph.D

Research Partners

* NASA/Kennedy Space
* Florida Solar Energy Center p; -
* Energy Partners
* Florida Institute of
Phosphate Research
* Florida Department
of Energy
* Harris Semiconductor

For more information, contact

Florida Institute
of Technology 19.
Chemical Engineering Program
College of Engineering
Division of Engineering Sciences
150 West University Boulevard
Melbourne, Florida 32901-6975
(407) 674-8068 -

Chemical Engineering Education

Graduate Studies in Chemical Engineering
Master of Science and Doctor of Philosophy
Join a small, vibrant campus on Florida's Space Coast to reach your
full academic and professional potential. Florida Tech, the only
independent scientific and technological university in the South-
east, has grown to become a university of international standing.

Graduate Student Assistantships/
Tuition Remission available


Home of the 1996 Olympic Village

Georgia Intoitiu

( Techn(ogy

Chemical Engineering

The ~ ~ ~ ~~L Faut n herRsac

Hr Polymer
Science and
9 engineering
A.S. Abhiraman

SlReactor design,
W catalysis
William R. Ernst

Synthesis and
properties of
S modeling of
1 processes

Pradeep K. Agrawal

S\Mechanics of
plumes and
Larry J. Forney

PF % Molecular
modeling of
Peter J. Ludovice

Process design
and control,

thin film
science and

Tennis w. ness

Michael J. Matteson

SNc Mliccroelectron-
S ics, poismer
Sue Ann Bidstrup-Allen

3 Pulp and paper
Jeffery S. Hsieh

Charles A. Eckert

chemical vapor
Paul A. Kohl

two phase
flows, complex

Jeffrey E Morris


John D. Muzzy

- Biomechanics,
cell structures
Robert M. Nerem

mass transfer,
reactor design
Ronnie S. Roberts

l B extraction,
mixing, non-
A. H. Peter Skelland

reactor design

Mark U. White

E mulsion
Gary W. Poehlein

Ronald W. Rousseau

Process design
and simulation
Jude T. Sommerfeld

Timothy M. Wick

N ~ mechanisms
Mark R. Prausnitz

microbial and
animal cell
S u cultures
Athanassios Sambanis

Arnold F Stancell

ics, air

Jack Winnick

process design
^and scheduling
Matthew J. Realff

nass transfer

Mary E. Rezac

process control,

science and
Robert J. Samuels

synthesis and
separation, waste
Daniel W. Tedder Amyn S. Teja

Ajit P. Yoganathan

For more inforination, contact:
Dr. Ronald Rousseau, Chair
School of' Chemical Engineering
Georgia Institute of Techjjujugr
Atlanta, Georgia 30332-0100

and transport
phase equilibria,

What do graduate students say about the

University of Houston

Department of Chemical Engineering?

"It's great!"

"Houston is a university on the move. The chemical engineering department is ranked among
the top ten schools, and you can work in the specialty of your choice. The choice of advisor is
yours, too, and you're given enough time to make the right decision. You can see your advisor
almost anytime you want because the student-to-teacher ratio is low."

If you'd like to be part of this team, let us hear from you!

Biochemical & TissueEngineering Neal Amu
Reaction Engineering & Catalysis Vemuri B.
Electronic and Ceramic Materials Demetre E
Environmental Remediation Ernest He
Multiphase Flow John Killc
Nonlinear Dynamics Ramanan
Polymer & Macromolecular Systems
Process Control and Optimization


Dan Luss
Kishore Mohanty
Mike Nikolaou
Richard Pollard
William Prengle

Jim Richardson
Frank Tiller
Richard Willson
Frank Worley

8CA A.
+ + =1 +~ln RA

For an application, write:
Graduate Admissions Coordinator, Dept. of Chemical Engineering, University of Houston, 4800 Calhoun, Houston, TX 77204-4792, or call 713/743-4311.
The University is an Equal O'l ,*.. iir,, 'A4ti,,,,;,', Action Institution
Chemical Engineering Education

Chemical Engineering at

Where modern instructional and research laboratories,
together with computing facilities, support both student
and faculty research pursuits on an eighty-nine acre main
campus three miles north of the heart of Washington, DC.

-- Faculty and Research Interests

Mobolaji E. Aluko, Professor and Chair
PhD, University of California, Santa Barbara
Reactor modeling crystallization microelectronic and ceramic materials pro-
cessing process control reaction engineering analysis

Joseph N. Cannon, Professor PhD, University of Colorado
Transport phenomena in environmental systems computational fluid mechanics heat transfer

Ramesh C. Chawla, Professor PhD, Wayne State University
Mass transfer and kinetics in environmental systems- bioremediation incineration air and water pollution control
William E. Collins, Assistant Professor PhD, University of Wisconsin-Madison
Polymer deformation, rheology, and surface science biomaterials bioseparations materials science
M. Gopala Rao, Professor PhD, University of Washington, Seattle
Adsorption and ion exchange process energy systems radioactive waste management remediation of contaminated soils and
John P. Tharakan, AssociateProfessor PhD University of California, San Diego
Bioprocess engineering protein separations biological hazardous waste treatment bio-environmental engineering
Robert J. Lutz, Visiting Professor PhD, University of Pennsylvania
Biomedical engineering hemodynamics drug delivery pharmacokinetics

Herbert M. Katz, Professor Emeritus PhD, University of Cincinnati
Environmental engineering Program

For further information and applications, write to

Fall 1997 297

U The University of Illinois at Chicago

SDepartment of Chemical Engineering

MS and PhD Graduate Program *


John H. Kiefer, Professor and Head
Ph.D., Cornell University, 1961
E-Mail: Kiefer@UIC.EDU

Kenneth Brezinsky, Professor
Ph.D., City University of New York, 1978
E-Mail: Kenbrez@UIC.EDU
G. Ali Mansoori, Professor
Ph.D., University of Oklahoma, 1969
E-Mail: Mansoori@UIC.EDU

Sohail Murad, Professor
Ph.D., Cornell University, 1979
E-Mail: Murad@UIC.EDU

Ludwig C. Nitsche, Associate Professor
Ph.D., Massachusetts Institute of Technology, 1989

John Regalbuto, Associate Professor
Ph.D., University of Notre Dame, 1986
Hector R. Reyes, Assistant Professor
Ph.D., University of Wisconsin, Madison, 1991
E-Mail: HReyes@UIC.EDU
Satish C. Saxena, Professor
Ph.D., Calcutta University, 1956
E-Mail: Saxena@UIC.EDU
Stephen Szepe, Associate Professor
Ph.D., Illinois Institute of Technology, 1966
E-Mail: SSzepe@UIC.EDU
Christos Takoudis, Professor
Ph.D., University of Minnesota, 1982
E-Mail: Takoudis@UIC.EDU

Raffi M. Turian, Professor
Ph.D., University of Wisconsin, 1964
E-Mail: Turian@UIC.EDU


Transport Phenomena: Transport properties of fluids, slurry transport,
multiphase fluid flow and heat transfer, fixed and fluidized bed combustion,
indirect coal liquefaction, porous media.
Thermodynamics: Molecular simulation and statistical mechanics of liquid
mixtures. Superficial fluid extraction/retrograde condensation, asphaltene
characterization. Reverse osmosis separations.
Kinetics and Reaction Engineering: Gas-solid reaction kinetics,
diffusion and adsorption phenomena. Energy transfer processes, laser diagnostics,
and combustion chemistry. Environmental technology, surface chemistry, and
optimization. Catalyst preparation and characterization, structure sensitivity, and
supported metals. Chemical kinetics in automotive engine emissions. Enzyme
Kinetics. Novel approaches to chemical kinetics and catalysis, in situ surface
Biochemical Engineering: Biodegradable polymers. Nonaqueous
enzymology. Optimization of mycobacterial fermentations. Bioseparations.
Materials: Microelectronic materials and processing, heteroepitaxy in group
IV materials, and in situ surface spectroscopies at interfaces. Combustion
synthesis of ceramics and synthesis in supercritical fluids.

For more information, write to
Director of Graduate Studies Department of Chemical Engineering
University of Illinois at Chicago 810 S. Clinton Chicago, IL 60607-7000 (312) 996-3424 Fax (312) 996-0808
Chemical Engineering Education

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