PICS Colloquium: Influence of particle size distribution on random close packing with Eric Weeks

Abstract: The volume fraction phi for random close packed (RCP) spheres is approximately 0.64. It is well known that higher RCP volume fractions are achieved by using collections of particles with a variety of sizes. The variety of sizes is often quantified by the polydispersity of the particle size distribution: the standard deviation of the radius divided by the mean radius. I’ll show that for 2D and 3D packings, the skewness also plays an important role (related to the third moment of the size distribution). I will also discuss some of our work on random close packing in confined spaces.

Bio: Eric Weeks earned his undergraduate degree in engineering physics at the University of Illinois at Urbana-Champaign. (“Engineering” physics meant he had to take drafting and Fortran.) In 1997 he graduated with a Ph.D. in physics from the University of Texas at Austin, working in the Center for Nonlinear Dynamics with Prof. Harry Swinney. His dissertation was on experiments studying anomalous diffusion and atmospheric phenomena. He started a postdoctoral fellowship at the University of Pennsylvania with Prof. David Weitz and Prof. Arjun Yodh, and finished his postdoctoral work at Harvard University when the Weitz lab moved there. In January 2001 he joined the faculty of Emory University, where he is currently a Dobbs Professor of Physics.