9623694 Reppy Threee topics will be pursued which illustrate different aspects of superfluid physics under conditions of disorder: 1. The superfluid transition of liquid helium in porous (Vycor) glass, specifically a measurement of the heat capacity anomaly at the transition - for which a major advance in the art of low-temperature calorimetry will be required 2. Dissipative superflow in porous media. The system serves as a boson analog of a high-Tc superconductor, in which the understanding of the vortex fluid and the flux flow is of technically important. 3. The superfluid phase found in the second layer of 4He adsorbed on graphite - a unique phase that calls for further investigation. %%% Superfluid helium is employed to illuminate problems of general interest in condensed-matter physics. The effect of impurities and structural defects on "critical phenomena" and other properties will be examined. The study of liquid helium contained in a porous medium, where the structure acts as a "quenched impurity", can provide valuable insights and tests for understanding the fundamental problem of disorder in condensed-matter systems. ***
