9306791 Maynard This project will study a range of interface phenomena using novel experimental research which takes adantage of the ultra-high purity, well documented properties, and favorable acoustic characteristics of liquid helium. Other contemporary topics in dynamics, such as superdiffusion, noise and localization in mesoscopic electronic systems, will be studied with acoustic analogs. The interfacial pehnomena to be investigated include fluid interfaces, film rupture, cavitation, fluid jet breakup. These phenomena are scientifically interesting because they involve the fundamental effects of systems in metastable equilibrium approaching true equilibrium through hydrodynamic instabilities, nonlinear dynamics or dynamics on a molecular level. %%% This project uses ultrapure liquid helium as an acoustic medium to investigate a number of fluid interface problems that bear on many practical problems, including foam production, emulsions, spraying mixing, cavitation, lubrication, ultrasound applications, as in medicine, and others. The project also involves novel acoustical models of electronic phenomena occuring in semiconductors, metals and other materials. The acoustic measurements can shed light on the quantum phenomena in a way not possible using other techniques. ***