Anomalous Transport in Conical Granular Piles
  Experiments on 2+1-dimensional piles of elongated particles are performed. Comparison with previous experiments in 1+1 dimensions shows that the addition of one extra dimension to the dynamics changes completely the avalanche properties, appearing a characteristic avalanche size. Nevertheless, the time single grains need to cross the whole pile varies smoothly between several orders of magnitude, from a few seconds to more than 100 hours. This behavior is described by a power-law distribution, signaling the existence of scale invariance in the transport process. 
Peter Ahlgren (1), Mikkel Avlund (1), Ib Klewe (1), Jonas Nyvold   Pedersen (1), and Alvaro Corral (2,1) ((1) Niels Bohr Ins...