2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/197648The Müller-Israel-Stewart second order theory of relativistic imperfect fluids based on Grad's moment method is used to study the expansion of hot matter produced in ultra-relativistic heavy ion collisions. The temperature evolution is investigated in the framework of the Bjorken boost-invariant scaling limit. The results of these second-order theories are compared to those of first-order theories due to Eckart and to Landau and Lifshitz and those of zeroth order (perfect fluid) due to Euler.5 pages, 4 figures, size of y-axis tick marks for Figs. 3 and 4 fixedNuclear Theorytext