  In this note we discuss a paradigmatic example of interacting particles
subject to non conservative external forces and to the action of thermostats
consisting of external (finite) reservoirs of particles. We then consider a
model of granular materials of interest for experimental tests that had
recently attracted lot of attentions. This model can be reduced to the
previously discussed example under a number of assumptions, in particular that
inelasticity due to internal collisions can be neglected for the purpose of
measuring the large deviation functional for entropy production rate. We show
that if the restitution coefficient in the granular material model is close to
one, then the required assuptions are verified on a specific time scale and we
predict a fluctuation relation for the entropy production rate measured on the
same time scale.
