Publications [#245643] of Robert P. Behringer

Papers Published
  1. Geng, J; Behringer, RP, Diffusion and mobility in a stirred dense granular material., Physical Review Letters, vol. 93 no. 23 (December, 2004), pp. 238002 [15601205], [doi] .

    We describe a probe of diffusivity (D) and mobility (B) for a dense 2D granular system. We introduce random motion by stirring, and characterize D by particle tracking. To measure B we measure the force needed to push a particle through the medium at fixed velocity, v, using three sizes of tracer particle. We find simple Brownian diffusion, but B depends strongly on v because the force needed to push a tracer through a sample is nearly independent of v. Data for D/B depend on the tracer particle size.