An estimate of the first logarithmic term in the density expansions of transport coefficients of moderately dense gases

In this paper, we present an estimate of the coefficient of the first logarithmic term in the density expansions of transport coefficients of moderately dense gases. We formulate the theory for a gas of hard sphere molecules. Then the essential approximation made in this work is to replace the Lorentz-Boltzmann and the linearized Boltzmann operators by B.G.K. model collision operators. This allows us to compute the coefficient of interest in a simple way. We compare the results of this approximation with previous results.