  The Maxwell-Boltzmann moment system can be seen as a particular case of a
mathematically more general moment system proposed by Machado in Ref [1]. This
last moment system, whose integral generating form and a suggested continuous
distribution are presented here, is used in this letter to theoretically show
(one of) its usefulness: A flexible Prandtl number can be obtained in both the
Boltzmann equation and in the lattice Boltzmann equation with a conventional
single relaxation time Bhatnagar-Gross-Krook collision model.
