TRANSIENT PHENOMENA, SELF-DIFFUSION, AND ORIENTATIONAL EFFECTS IN VIBRATED POWDERS

We explore the rich behavior of vibrated powders, focusing on the relaxation of transients between vibrational steady states, on the diffusion of independent particles, and on ''global'' and ''local'' angular distributions of contacting particles. When examined as a function of vibrational intensity, these are shown to be explicable in terms of a model of independent-particle and collective excitations. Our data provide a wealth of information about topics as diverse as consolidation under packing, the roughness of granular piles, and the local structure of bridges and arches in shaken packings.