Mechanical and thermodynamic behavior of materials, material processing problems, such as extrusion and molding of polymer; formulated the widely-used BKZ (Bernstein, Kearsley and Zapas) model, in which the ideas of finite elastic strain are incorporated into a theory of fluids which treats the thermodynamics as well as the mechanics of such media; computational work on polymeric fluid flows, in part responsible for a finite element formulation known as flucode; tracer analysis of blood circulation and of recycle reactors.
