  Thermodynamical properties of the nuclear matter at sub-saturation densities
were investigated using a simple van der Waals-like equation of state with an
additional term representing the symmetry energy. First-order
isospin-asymmetric liquid-gas phase transition appears restricted to isolated
isospin-asymmetric systems while the symmetric systems will undergo
fragmentation decay resembling the second-order phase transition. The density
dependence of the symmetry energy scaling with the Fermi energy satisfactorily
describes the symmetry energy at sub-saturation nuclear densities. The
deconfinement-confinement phase transition from the quark-gluon plasma to the
confined quark matter appears in the isolated systems continuous in energy
density while discontinuous in quark density. A transitional state of the
confined quark matter has a negative pressure and after hadronization an
explosion scenario can take place which can offer explanation for the HBT
puzzle as a signature of the phase transition.
