Professor Stone's general interests are as follows. I investigate the mechanical properties of solids, specifically plastic flow and rupture, relating these phenomena to their underlying, atomic-scale physical mechanisms. In one project, I examine the physics of strengthening in thin (<1mm) metal films on substrates for applications, e.g., as hard coatings or as metallizations on semiconductors. Sensitive, nanometer-scale indentation techniques are used to characterize the rate- and temperature-dependence of the flow stress. In another project, I examine, in situ, how cracks initiate and propagate along the grain boundaries of solder alloys during fatigue; application of this work targets the design and performance of microelectronic packages. In all of these studies, combining both experiments and theory, the emphasis is on how the mechanical responses of fine-scale structures can be compared and contrasted with those of bulk materials.