The long-time asymptotics of certain nonlinear, nonlocal,
diffusive equations with a gradient flow structure are analyzed.
In particular, a result of Benedetto, Caglioti, Carrillo and
Pulvirenti [BCCP98] guaranteeing eventual
relaxation to equilibrium velocities in a spatially homogeneous
model of granular flow is extended and quantified by computing
explicit relaxation rates. Our arguments rely on establishing
generalizations of logarithmic Sobolev inequalities and mass
transportation inequalities, via either the Bakry-Emery method or
the abstract approach of Otto and Villani [OV00].