“…Remark 4.1. When ν is a scalar (or a pseudo-scalar), an appropriate procedure to derive the pertinent balance of microstructural interactions, instead of postulating it (in this specific case, a first postulate of such a scalar balance seems to have been suggested by Nunziato & Cowin [51]), is based on a requirement of invariance in structure for the second law, written in terms of Clausius-Duhem's inequality, under general diffeomorphism-based changes of observer, those described in Remark (2.1); this covariance principle for the second law of thermodynamics [42] requires, in short, that if an observer records a process as a dissipative one, any other observer related with it by diffeomorphisms must record the same dissipative character. To obtain a scalar balance of microstructural interactions, without postulating it, we could also adopt covariance of the first principle of thermodynamics (balance of energy), asking its covariance with respect to general diffeomorphism-based changes of observers, and adapting to the present case Marsden-Hughes' theorem [25]; however, we would not be able to obtain dissipative (macro and micro) stress components.…”