Hershel Markovitz, Emeritus Professor of Mechanics and Polymer Science in the Department of Chemistry of Carnegie Mellon University died on 29 August in Jerusalem, where he had been living since 1987. He was born in McKeesport, PA, on October 11, 1921, and resided in Pittsburgh, PA, until moving with his wife Marion to Jerusalem in 1987. He was preceded in death by Marion and is survived by their three children and his brother.
Hershel was active in scientific affairs, serving as the chairman of the American Physical Society's Division of High Polymer Physics (1961-2) and president of the Society of Rheology (1969-71). He served on editorial boards and had editorial positions with the Transactions of the Society of Rheology (1967-9) and the Journal of Polymer Science (1966-88). In 1967 he was awarded the Bingham Medal of the Society of Rheology.
He earned a B.S. in Chemistry from the University of Pittsburgh in 1942 and a Ph.D. from Columbia University in 1949 with a dissertation on the viscosity of polyacrylic acid solutions. He joined a Fellowship of the Mellon Institute in 1949 and began a long and extremely successful career of research on the rheology of polymers and their solutions. Among his early collaborators at the Institute were Louis Zapas and Frank Padden Jr. Hershel's early research revealed the strategies pursued throughout his career: the construction of instruments for measuring dynamical mechanical properties and the development of the theory needed to properly interpret results obtained with those instruments. He administered the Fellowship from 1954 to 1957, the period in which he began his seminal experimental and theoretical research on normal stress effects in what we today call viscometric flows. It was also in this period that Edward Casassa joined the Fellowship for research on dilute poly! mer solutions.
The restructuring of the Mellon Institute in 1957 brought in Paul Flory as the Director of Research, Thomas Fox to be in charge of polymer research, the promotion of Edward Casassa and the recruitment of Bernard Coleman to join Hershel as Senior Fellows of the Institute, and the appointment of several new Fellows in the polymer group, including Donald Plazek and Guy Berry. Around this time, Hershel and Casassa published their research on the second virial coefficient of polymer solutions and Hershel published papers on normal stress effects that had a strong influence on the research of Coleman and Walter Noll, then at the Carnegie Institute of Technology (C.I.T.), on their development of a general theory of viscometric flows.
In the decade that followed, Hershel deepened his interest in normal stress effects while continuing his experimental research in linear viscoelasticity in collaboration with Plazek with emphasis on the frequency and temperature dependence of dynamic properties. He was a Visiting Lecturer at the Johns Hopkins University (1958-9) and a Fulbright Fellow at the Weizmann Institute (1964-5) and did research with Coleman revealing that when second-order fluids are considered to be slow-flow approximations to fluids with long-range, but gradually fading, memory there will be algebraic relations between the intrinsically nonlinear normal stress effects and certain parameters that occur in the linear theory of viscoelasticity, and these relations appear capable of experimental verification. In that period he collaborated with Coleman and Noll in the writing of the book Viscometric Flows of Non-Newtonian Fluids, Theory and Experiment.
The merger of Mellon Institute and C.I.T. to create Carnegie Mellon University in 1967 brought a professorship to Hershel and the opportunity to create courses in rheology in the graduate program in polymer science at the new university. He taught these courses until his retirement in 1986, being recognized for his excellence in teaching by the award in 1982 of the Julius Ashkin Teaching Award of Carnegie Mellon University. His scholarship and energy brought forth publications on the history of rheology, several encyclopedia articles, and films still in use that illustrate fascinating implications of the normal stresses that occur in viscometric flows. His research in that period included experimental studies of linear viscoelastic properties of polymer solutions (with Plazek), semicrystalline polysilaxane, and polymer dispersions (with Berry), along with theoretical studies study with Coleman of implications of the theory of materials with fading memory.
During his career Hershel published research papers with 26 different co-authors and worked informally with many more. He was generous with his time and knowledge, attributes much appreciated by the many students he helped, as well as by those of us who shared the wonderful opportunity to be his colleague and friend.
On behalf of the Mellon Institute Polymer Group,
