In Memoriam: Ziyaeddin Ahmet Akçasu

The NERS Professor Emeritus will be remembered for his contributions to multi-component polymer solutions, his gift for teaching, and gentle spirit.

Ziyaeddin “Ziya” Ahmet Akçasu, professor emeritus of nuclear engineering and macromolecular science and engineering, passed away on Saturday, November 6, 2021, at the age of 97. Akçasu was recognized not only within U-M, but also nationally, for his work on multi-component polymer solutions.

Akçasu was born in 1925 in Aydın, Turkey. He graduated from Istanbul Technical University in 1948 with a B.S. in electronics and then became an associate professor at the same university. In 1957, he came to the U.S. through the Eisenhower Fellowship to work at Argonne National Laboratory in Chicago. 

In 1959, Akçasu began his graduate studies at NERS and received his PhD in 1963. He joined our faculty in 1963 as an assistant professor and was promoted to associate professor in 1965, and professor in 1968.

Ziyaeddin Ahmet Akçasu portrait, vintage
Akçasu in the 1960s

An extremely prolific researcher with an international reputation, Akçasu authored over 95 articles and contributed greatly to the fields of nuclear reactor dynamics and statistical mechanics. His achievements in reactor dynamics and noise analysis served as a foundation for the industry to begin to understand the concept of stability in reactor operation. 

In the field of statistical mechanics, Akçasu was best known for improving our understanding of the dynamics of polymer solutions. He was a principal in the development of generalized hydrodynamic equations and studied time correlations in simple fluids. In 1984, Akçasu and colleagues formulated the dynamics of multi-component polymer solutions, which has been widely used since then in the interpretation of light and neutron scattering experiments on such systems. The formulation of a new method for studying the dynamics of multi-component polymer mixtures has contributed significantly to the dynamics of polymer melts. 

Even with his international renown as a theoretical researcher, he was the most gifted classroom teacher the department had. He loved all of the students and that feeling was fully reciprocated.

Prof. David Wehe

Akçasu’s achievements were recognized with a symposium in his name at the 1994 American Chemical Society meeting. Six special sessions at the annual meeting were designated as “Ziya Akçasu Special Sessions.”

In his home country of Turkey, Akçasu was a pioneer in several technological advancements such as the establishment of the first TV broadcasting in Istanbul in 1952, and the advancement of Küçükçekmece Nuclear Research and Training Center. 

Akçasu will be remembered as an excellent teacher. “Even with his international renown as a theoretical researcher, he was the most gifted classroom teacher the department had,” said Prof. David Wehe. “He loved all of the students and that feeling was fully reciprocated.” 

In 1993, Akçasu earned the Excellence in Teaching Award from the College of Engineering and was named outstanding teacher of the year by NERS students. In 2004, he was honored by U-M’s Macromolecular Science and Engineering program. 

Akçasu retired in 1995 and continued to work as an emeritus professor until 2010. For many years after his official retirement, on the weekend or early in the morning, he could be found in the Cooley Building. When passing the dark offices of his colleagues he could be heard saying, “Who retired, anyway?”

He is survived by a daughter (Nur), two sons (Feza and Aydın), and three grandchildren (Audrey, Brian, and Nora). Akçasu was a great colleague and contributor to the success of our department and will be greatly missed.

The NERS Community Remembers Prof. Ziya Akçasu 

Ziya was an accomplished scientist with expertise in broad areas of physics and engineering. He was also a wonderful mentor, colleague, and friend, and I will surely miss him. I have been aware of Ziya’s legendary teaching style and his spectacular lecture notes for various classes. I remember reviewing parts of his lecture notes for stochastic process and reactor kinetics classes and taught a limited number of classes together with him.  I clearly remember how he would cover the whole blackboard in small but clear handwriting, usually with a single index card serving as his lecture note!  
—Prof. John Lee

Ziya Akcasu and Dick Osborn were the two faculty members who took new young faculty under their wings and taught them how to survive in the competitive world of university teaching and research in the Department of Nuclear Engineering. I worked closely with Ziya in my early years (even writing a book with him), and viewed him as both my teacher and colleague. His research and teaching were of the highest quality, and his generosity and spirit were just what the new faculty needed. He will be greatly missed.
Prof. James Duderstadt

Ziya was a good friend, a thoughtful colleague, a gifted scientist, and an inspiring teacher. I was fortunate to have known Ziya in all these ways for almost 50 years. I will miss him.
Prof. William Martin

Ziya was an influential professor in my plasma physics graduate education from 1974–1978, His clear discussions from Krall and Trivelpiece on Fokker Planck transport led me to a key insight in my dissertation to use the FP collision operator to derive multigroup cross-sections to use in a discrete ordinates transport code in response to Jim Duderstadt’s (my thesis advisor) request that I look into developing a transport method for simulating non-local heat conduction and electron transport for laser-driven ICF. Ziya was also a highly approachable member of the faculty who was always generous with his time for technical discussions, or the odd game of chess. Ziya quickly learned that I was no match for him in chess—but he was always gracious and encouraging. We continued to have periodic interactions when I visited Ann Arbor for various departmental functions. On one visit I had the pleasure of attending a NERS dinner where we recognized his 80th birthday! To me, Ziya was an ideal role model for an emeritus professor. He always had a cheerful demeanor and fully enjoyed his access to the university facilities for keeping both body and mind healthy! Despite not being physically proximate to Ann Arbor and the University, I have worked to establish a similar environment for keeping mind and body strong—including participating as an Adjunct Professor in NERS—based on the example that Ziya set. I am grateful for the impact that he had on my education and his friendship throughout the years—he will always be remembered!
Prof. Tom Mehlhorn

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