2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/81571We analyze the character of the shell effects/Casimir energy in inhomogeneous fermion systems. We estimate magnitude of the shell effects and discuss their dependence on a number of physical parameters (geometry, fermion density, temperature).4 pages, no figures; talk at XXXV Zakopane School Of Physics, Zakopane, Poland, 5 - 13 September 2000; to appear in Acta Phys. PolNuclear TheoryCondensed Mattertext