Alumni Spotlight: Eric Shaqfeh reflects on his time at Stanford and the legacy of Andy Acrivos

Eric S.G. Shaqfeh

Lester Levi Carter Professor and Professor of Mechanical Engineering
Chemical Engineering

"I came to Stanford University for the first time in 1981 as a graduating student from Princeton University. I had been admitted to the PhD class in Chemical Engineering, and my dream was to come to Stanford and work with Andy Acrivos. My mother openly cried about my decision; we were a very poor family, and the plan had been for me to get a good job in industry with a big company on the East Coast—perhaps Dow or DuPont. I was the first in my family to attend college, and college was viewed as a means for economic advancement. Mom thought I had decided to be a student “forever.” At the time, there was an energy crisis, and jobs were plentiful, particularly if you had a chemical engineering degree. However, during my education, I became enamored with physics, applied mathematics and mechanics. I would have pursued a physics degree (I was in the Engineering Physics program) had it not been for the lack of job prospects in physics at that time. My mentors at Princeton suggested that I might be “professor material,” and if I wanted to be a professor in chemical engineering—particularly with an emphasis on applied mathematics and mechanics—then Andy Acrivos was the person to advise my PhD. However, they warned that it would not be easy. I visited the Stanford campus in early 1981, and on that visit, I also fell in love with Northern California. I explained to my mother that they were going to pay me to get my PhD and that I could always get an industrial job if things didn't work out in my search for a faculty position. That allayed her fears a bit, but it really wasn't until much later that she became comfortable with my attending Stanford.

When I came to Stanford, I like to say that “giants roamed the campus.” This means that if you were interested in applied mathematics and mechanics, there really was nothing like it anywhere in the United States. The likes of Joe Keller, Milton Van Dyke, Tom Hughes, Bill Reynolds and Andy Acrivos were all in their “heyday,” and each taught classes individually to captivated audiences. In the Department of Chemical Engineering, other “giants” like Michel Boudart and Bud Homsy were teaching material from a unique perspective that could be found nowhere else. The department itself was quite small—around ten faculty—and the PhD classes were also small; mine had nine students. However, these nine students were among the top one or two from all the leading chemical engineering programs in the country, and we all bonded as fast friends. Scholarship was of paramount importance for the faculty, both in how the classes were taught and in how they ran their groups. All groups were relatively small—a group size of ten was considered quite large. The classes were quite rigorous and difficult, and I learned a tremendous amount. Moreover, there were “two” levels of qualifications: prequals and quals. “Prequals” were by invitation only and were administered to those who “didn't do well in classwork.” There were no set rules as to who took these, but the faculty made a decision each year on some percentage of students (about 15%) who would take them. Generally, these students, with a few exceptions, were asked to leave Stanford with their Master's degrees. Quals consisted of an oral examination in front of the faculty as a whole, based on research that you had accomplished for six months after choosing an advisor.

As I had come to Stanford to work with Andy Acrivos, I indeed requested to be placed in his group at the beginning of the Spring quarter of my first year. (Generally, people submitted a list of three ranked choices, but you almost always received your first choice.) However, by that time, I realized why people had warned me that working with him would “not be easy.” Andy’s first class, which I took in the Winter quarter, was by far the most difficult course in the first year, or for that matter, any year. Andy’s approach to education was to teach one to learn on their own. He generally presented results at a very high level, with relatively brief derivations, and then you were asked to spend the time needed to understand those derivations. In general, this took a tremendous amount of outside work and background reading. His tests and problem sets were in this same vein, with relatively little information given in the problem statements. Essentially, to do well, you had to want to learn; it was the ultimate example of teaching by “opportunity”—you had the chance to learn a lot, but if you did not take that opportunity, then that was your choice, and you lived with the consequences. Andy gave grades that were, in general, much lower on average than those that appear in today’s graduate classes. He had no problem failing you in a class, even if you worked hard, and he was disinterested in working with people who were not highly motivated to learn. In that sense, the rewards of his class teaching were very large if you viewed the reward as a deep understanding of the class material and were ready to put in the effort.

Andy’s advising style was very much like his teaching style. Very few people were motivated to work with him because his standards were so high and the amount of work expected was enormous. Andy did not “pull his punches” in discussions with his PhD students—if you said something that was “naïve,” he told you so in no uncertain terms. When I started to work with Andy, he spent about an hour reviewing two problems, which he said could make a PhD for me. I was asked to think about it and decide. I came back and chose my problem, and at that point, by his own statement, he said “fine.” Then he indicated a suggested starting point and said he was taking a “step back.” What this meant, in retrospect, was that I should have my next conversation with him only when I had something interesting to say about the problem in terms of my solving it. While I attempted to have a number of conversations with Andy about the problem, these were all very brief indeed, usually ending with some statement about how I did not really know anything yet. One of the worst days as a graduate student was walking out of Andy Acrivos’s office after being told how naïve my thinking was. You soon realized that what you should do is talk to the other students in his group. They were great, wonderful, and helpful—including Ashok Sangani, Rob Davis and Dave Leighton, who are now Chemical Engineering faculty at other institutions. I therefore learned from working with his students, and it was perhaps two years after starting in his group until I had a detailed conversation about my PhD problem with Andy. In this sense, Andy was a “tough” person as your advisor; however, it was, again, an opportunity. Andy was teaching me how to be independent and do research at the highest level on my own. He set the standard and “took a step back.” I did not find out until much later that he would check in regularly with his senior students about my progress, and when I was a senior student, he checked with me about the students who came thereafter.

Moreover, Andy “walked the walk” in terms of research. His work ethic was phenomenal; he worked six days a week starting at 6 a.m. until early evening, and he expected—though no specific guidelines were set—that you would be in the office most of that time as well. If you were not in the office on the weekend, then he would generally ask you, “Where have you been?” Weekend work and Monday results discussions were standard in the Acrivos group.

During these years, there was a dedicated group of perhaps ten students in Bud Homsy’s and Andy Acrivos’s group who decided there were topics to learn that were not covered by coursework on campus. We therefore formed reading groups and taught ourselves such topics—for example, nonlinear dynamics and hydrodynamic stability theory. In these groups, we would select a text and read it from cover to cover, with a group member leading a discussion on each section. Bud participated in these groups and became the de facto “teacher.” Through this experience, the groups became very close as we shared our ignorance of the subject matter, but also our learning. Bud was an enormous proponent of “curiosity-driven” research, and as a result, this group would regularly seek an understanding of fluid mechanics phenomena that came up in our reading, leading to further topics. Bud was a very different mentor than Andy, and the two complemented each other in a way that is hard to describe. Suffice it to say that I am a very lucky person to have known them and been mentored by them.

Looking back on my years as a Stanford graduate student, I came away with an amazing education and a feeling of confidence in my own independent abilities to tackle engineering problems. Moreover, I felt that “scholarship”—particularly the development of new ideas—was paramount at a university and perhaps the biggest gift that a university could offer to society, apart from the intellectual and personal development of students. I went on to a postdoc in the Department of Applied Mathematics and Theoretical Physics (D.A.M.T.P.) at the University of Cambridge, England, and I “fit right in” because of my training—not a small feat since the department included Stephen Hawking among its faculty. Thereafter, I finally took the industrial job that my mother wanted—working at Bell Laboratories for three years. I was again marvelously prepared for this experience. When I stepped into teaching, again at Stanford University, my mom didn't cry this time, as she trusted that Stanford had done right by me the first time."