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became a Professor of Chemical Engineering at the University of Michigan in 1996, after working for 17 years at Bell Laboratories in Murray Hill, New Jersey. He received a B.S in1975, an M.S. in 1977, and a Ph.D. in 1980, all in chemical engineering from the University of Minnesota.
Larson's research interests include the structure and flow properties of viscous or elastic fluids, sometimes called "complex fluids", which include polymers, colloids, surfactant-containing fluids, liquid crystals, and biological macromolecules such as DNA. He is also interested in fluid mechanics, including microfluidics, and transport modeling. He has written numerous scientific papers and two books on these subjects, including a 1998 textbook, "The Structure and Rheology of Complex Fluids."
Larson was the President of the Society of Rheology (SOR) from 1997 to 1999, and served on the Executive Committee of that Society during the period 1991 to 2001. He is a Fellow of the American Physical Society (APS), and is a member of the SOR, the APS, the American Chemical Society (ACS), the American Association for the Advancement of Science (AAAS), the National Academy of Engineering (NAE), and the American Institute for Chemical Engineers (AIChE), where he currently serves on the Fluid Mechanics Programming Committee. In 1996, he was named the Prudential Distinguished Visiting Fellow at the Isaac Newton Institute in Cambridge England, in 2000 became the G.G. Brown Professor of Chemical Engineering at the University of Michigan, and in 2002 received the Bingham Medal from the Society of Rheology. He is currently chairman the Chemical Engngineering Department of the Univ. of Michigan, Ann Arbor, MI, USA
Rothstein is an Assistant Professor of Mechanical and Industrial Engineering at the University of Massachusetts. He received his Ph.D. under the supervision of Gareth McKinley at MIT. Rothstein’s background is in hydrodynamic stability, experimental non-Newtonian and Newtonian fluid dynamics, extensional and shear rheology, and novel non-invasive optical measurement techniques. He has published a number of papers in these areas including a recent article in Physics of Fluids which was awarded the prestigious Francois Frenkiel award for significant contribution to the field of fluid mechanics by a young investigator. He has designed and developed a filament stretching rheometer capable of simultaneously measuring tensile stress, strain and flow induced birefringence of complex fluids in transient homogeneous uniaxial extensional flows. His work on the behavior of polymer solutions and wormlike micelle solutions in extensional flows and mixed shear and extensional flows has led to the development of new constitutive models capable of accurately capturing the non-equilibrium dynamics and the prediction of stress-conformation hysteresis.
Winter's long-standing interest in experimental rheology began about 30 years ago when he could not find suitable rheological material data for his numerical calculations. Soon it became obvious that obtaining rheological data was not the main problem; converting these data into useful rheological material functions such as time spectra, viscosity, and modulus was the most difficult step. Little help was available here. A breakthrough came with Baumgaertel’s 1987 discovery of a robust method of converting dynamic mechanical data from the frequency to the time domain. This suddenly allowed an efficient data analysis and gave increased insight into the underlying phenomena. Since then, after much collaborative work, the data anlysis methods have become user-friendly and comprehensive while giving answers within minutes. The new methods have found widespread application. The original code was developed in collaboration with M. Baumgaertel and P. Soskey. M. Mours converted the original DOS code to visual C++ and introduced many methods from the literature. Recently, in collaboration with international experts, we extended the IRIS code and began to access molecular theory, non-linear viscoelasticity theory, and molecular simulation.
Winter has been educated mostly in Stuttgart, Germany, but he also studied in Berlin (Germany), Stanford (California), and Madison (Wisconsin). He is faculty at the University of Massachusetts Amherst since 1979. He received the Bingham Medal of the Society of Rheology, the v. Humboldt Price, and a Creativity Award of NSF. Winter is editor of Rheologica Acta since 1989. Winter and his group have been studying the rheology of polymers near transition states (phase separation, ordering transitions, connectivity transitions, crystallization, electric field induced gelation) with a wide range of experimental methods. Besides experimental rheology, Winter's group also develops novel polymeric materials through processing.