  We study the shearing of polydisperse and bidisperse media with a size ratio
of 10. Simulations are performed with a the two dimensional shear cell using
contact dynamics. With a truncated power law for the polydisperse media we find
that they show a stronger dilatancy and greater resistance to shearing than
bidisperse mixtures. Motivated by the practical problem of reducing the energy
needed to shear granular media, we introduce "point-like particles"
representing charged particles in the distribution. Even though changing the
kinematic behavior very little, they reduce the force necessary to maintain a
fixed shearing velocity.
