  We have studied the variation of a thermodynamic quantity, the strange
chemical potential, in the phase diagram of nuclear matter, by employing the
partition function in each domain and enforcing strangeness conservation. We
propose that the change in the sign of the strange quark chemical potential,
from positive in the hadronic phase to negative in the deconfined quark-gluon
phase, to be a new, unique, concise and well-defined indication of the
quark-deconfinement phase transition in nuclear matter. This signature is
independent of model parameters and interaction mechanisms. We propose also
that, for a state in the deconfined region following an isentropic path to
hadronization via a second order phase trasition, the fugacities of the
equilibrated quark flavours, once fixed in the primordial state, remain
constant throughout the hadronization process. This would enable the knowledge
of the thermodynamic quantities of states situated beyond the hadronic phase.
Data from nucleu-nucleus interactions at AGS and SPS give support to our
proposals.
