  We experimentally investigate the energy dissipation rate in sinusoidally
driven boxes which are partly filled by granular material under conditions of
weightlessness. We identify two different modes of granular dynamics, depending
on the amplitude of driving, $A$. For intense forcing, A>A_0, the material is
found in the collect-and-collide regime where the center of mass of the
granulate moves synchronously with the driven container while for weak forcing,
A<A_0, the granular material exhibits gas-like behavior. Both regimes
correspond to different dissipation mechanisms, leading to different scaling
with amplitude and frequency of the excitation and with the mass of the
granulate. For the collect-and-collide regime, we explain the dependence on
frequency and amplitude of the excitation by means of an effective one-particle
model. For both regimes, the results may be collapsed to a single curve
characterizing the physics of granular dampers.
