Stella Dernini

Calorimetric study of molecular interactions in mixtures of substances containing carbonyl groups

Abstract A Tian-Calvet type calorimeter has been used to determine molar excess enthalpies, HE, as a function of concentration at atmospheric pressure and 298.15 K for some binary liquid mixtures containing linear ketones with tetrachloromethane or benzene and linear diketones with n-heptane or cyclohexane. The experimental HE results are interpreted in terms of molecular interactions and of the “homoproximity effect”.

Excess volumes and gibbs free energies of mixtures containing alkanenitriles

Abstract Excess volumes, VE, by means of a vibrating-tube densimeter, and Vapor-Liquid equilibria, by head-space gas-chromatographic analysis of the equilibrated vapour phase directly withdrawn from equilibration apparatus, of binary mixtures containing n-alkanenitriles with n-alkanes or cyclohexane, were determined at 298.15 K. Measurements of the test mixtures, ethanol + cyclohexane were also made. Excess molar Gibbs free energies, GE, for the examined mixtures were obtained by a least - squares treatment of the equilibrium x, y results. The VEand GE values are positive for all the systems. The steric effect exerted by the alkyl groups adjacent to the CN group results in a regular decrease of the GE with increasing the number of alkyl groups in the alkanenitrile.

Gas bubble nucleation and tritium permeation through metallic walls in a liquid 83Pb-17Li blanket

Recent studies have given lower and lower values for the solubility of hydrogen isotopes in the eutectic 83Pb-17Li alloy, a candidate breeding material for the blanket of fusion machines. Therefore, thermodynamic stability for the gaseous phase under the high pressure reached at the bottom of the alloy containers can be achieved even for very low tritium concentrations in the liquid phase. A mathematical model to determine when tritium bubble nucleation occurs at an appreciable rate is presented. This model is used to predict tritium production behavior in the next European Torus (NET) tokamak.