Characterization of a Freezing/Melting Transition in a Vibrated and   Sheared Granular Medium
  We describe experiments on monodisperse spherical particles in an annular cell geometry, vibrated from below and sheared from above. This system shows a freezing/melting transition such that under sufficient vibration a crystallized state is observed, which can be melted by sufficient shear. We characterize the hysteretic transition between these two states, and observe features reminiscent of both a jamming transition and critical phenomena. 
Karen E. Daniels and Robert P. Behringer