We consider the moment equations for a kinetic model describing the interaction of monochromatic photons with gas-particles endowed with two internal energy levels. In the space-homogeneous case the stability of the equilibrium solution is analytically proven and numerically tested. In the...

A Boltzmann-like model for the description of processes of outgassing and contamination is proposed. The cavity /oR2, where the contaminants migrate during their motion from the source region /oR1 to the target /oR3, contains a random medium.