Rheology of sheared granular particles near jamming transition
  We investigate the rheology of sheared granular materials near the jamming transition point. We numerically determine the values of the critical fraction and the exponents for the jamming transition using a finite size scaling and the nonlinear minimization method known as the Levenberg-Marquardt algorithm. The exponents are close to our previous theoretical prediction, but there is a small discrepancy, if the critical point is independently determined. 
Michio Otsuki and Hisao Hayakawa
cond-mat.stat-mech cond-mat.soft