2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/123372We present the preliminary results of a two phases description of the ISM suited to numerical N Body T-SPH models of galaxy formation and evolution.2 pages, 2 figures - To appear in the Proceedings of the Conf. "From Stars to Galaxies: Building the Pieces to Build Up the Universe", Vallenari et al. eds., ASP Conf. SeriesAstrophysicstext