We have obtained the physical features of an isotropic and homogeneous environment on both theoretical and experimental levels, in particular when thermal features are linked through the λ = a ρC_p relation. As far as dispersed samples are particularly concerned, this largely used correlation is not confirmed in out-of balance non-homogeneous samples (transitional rate of flow /regime). So, we have developed, by electronic analogy a theoretical model that allows us to study the thermal performance and to discuss conditions of homogenization in such material.