Exergy of an open continuous medium.

Exergy is a very important thermodynamic quantity in several fields such as economy, engineering, and ecology and yet it has attracted little attention in pure physics. One of the main problems of the currently used definition of exergy is its dependence on an arbitrarily chosen reference state, which is the thermodynamic state of a reservoir the system is supposedly in contact with. In this paper, starting from a very general definition of exergy, a formula is derived for the exergy balance of a general open continuous medium without any reference to an external environment. A formula is also derived for the most suitable thermodynamic parameters of the Earth atmosphere when seen as an external environment in the usual exergy applications.

Local Polarization and Isothermal Local Equilibrium in Relativistic Heavy Ion Collisions.

We show that the inclusion of a recently found additional term of the spin polarization vector at local equilibrium which is linear in the symmetrized gradients of the velocity field, and the assumption of hadron production at constant temperature restore the quantitative agreement between hydrodynamic model predictions and local polarization measurements in relativistic heavy ion collisions at sqrt[s_{NN}]=200 GeV. The longitudinal component of the spin polarization vector turns out to be very sensitive to the temperature value, with a good fit around 155 MeV. The implications of this finding are discussed.

Collective Longitudinal Polarization in Relativistic Heavy-Ion Collisions at Very High Energy.

We study the polarization of particles in relativistic heavy-ion collisions at very high energy along the beam direction within a relativistic hydrodynamic framework. We show that this component of the polarization decreases much slower with center-of-mass energy compared to the transverse component, even in the ideal longitudinal boost-invariant scenario with nonfluctuating initial state, and that it can be measured by taking advantage of its quadrupole structure in the transverse momentum plane. In the ideal longitudinal boost-invariant scenario, the polarization is proportional to the gradient of temperature at the hadronization and its measurement can provide important information about the cooling rate of the quark-gluon plasma around the critical temperature.

Covariant statistical mechanics and the stress-energy tensor.

After recapitulating the covariant formalism of equilibrium statistical mechanics in special relativity and extending it to the case of a nonvanishing spin tensor, we show that the relativistic stress-energy tensor at thermodynamical equilibrium can be obtained from a functional derivative of the partition function with respect to the inverse temperature four-vector ß. For usual thermodynamical equilibrium, the stress-energy tensor turns out to be the derivative of the relativistic thermodynamic potential current with respect to the four-vector ß, i.e., T(µν)=-∂Φ(µ)/∂ß(ν). This formula establishes a relation between the stress-energy tensor and the entropy current at equilibrium, possibly extendable to nonequilibrium hydrodynamics.

Production of multiply heavy flavored baryons from quark gluon plasma in relativistic heavy ion collisions.

It is argued that in heavy ion collisions at the CERN Large Hadron Collider (LHC) there could be a sizable production of baryons containing two or three heavy quarks from statistical coalescence. This production mechanism is peculiar of quark gluon plasma, and the predicted rates, in heavy ion collisions at LHC energies, exceed those from a purely hadronic scenario, particularly for Xi(bc) and Omega(ccc). Thus, in addition to the interest in the discovery of these new states, enhanced ratios of these baryons over singly heavy flavored hadrons, like B or D, in heavy ion collisions with respect to pp at the same energy, would be a clear indication of kinetic equilibration of heavy quarks in the quark gluon plasma.

Overpopulation of Omega; in pp collisions: a way to distinguish statistical hadronization from string dynamics.

The Omega/Omega ratio originating from string decays is predicted to be larger than unity in proton-proton interactions at SPS energies ( E(lab) = 160 GeV). The antiomega dominance increases with decreasing beam energy. This surprising behavior is caused by the combinatorics of quark-antiquark production in small and low-mass strings. Since this behavior is not found in a statistical description of hadron production in proton-proton collisions, it may serve as a key observable to probe the hadronization mechanism in such collisions.

Emulsions of perfluorinated solvents for intravascular gas transport.

During the past several years we have progressed from the use of perfluorinated substances, which were good gas solvents but often produced unexpected physiological reactions, to a point where emulsions of pure perfluorinated substances can be made in a reproducible way. A standardized method of making emulsions has now been developed. The physical properties of the perfluorinated substances needed to make useful emulsions have been defined. Specifically, perfluorinated substances having vapor pressures above about 40 torr must be avoided as they produce pulmonary gas embolism; also lower boiling components having vapor pressures above about 40 torr must be excluded. The relationship between chemical structure and several physiological and pharmacological effects has been delineated. Perfluorinated substances containing only carbon and fluorine, or those containing carbon, fluorine, and either bromine or iodine have reasonably short dwell times in the liver. Perfluorinated iodo- and bromo-compounds dissolve oxygen and are radiopaque. Present iodo-perfluorinates are unstable in the presence of light. Perfluorodecalin can enter and leave the liver without changing the liver's ultrastructure. Both egg phospholipid and Pluronic F68 are useful in making perfluorodecalin emulsions. Perfluorodimethyladamantane makes a fine-particle stable emulsion. There is a bright future for perfluorinated substances in a number of areas of research in biology and medicine.

Perfluorocarbons having a short dwell time in the liver.

Perfluorinated organic liquids are useful as high capacity oxygen and carbon dioxide solvents. After intravenous infusion most of these perfluorinated emulsions are deposited in the liver and spleen in a matter of days, where they remain for the lifetime of the animal. Hence, while they may be useful as isolated organ perfusion media their value as artificial blood is limited. A family of perfluorocarbons has now been discovered, which, although deposited in the liver after circulation in the blood, leave the liver to be excreted via the lungs and skin in a matter of days without apparent harmn to the animal.