A class of solutions of the low energy string theory in four dimensions is studied. This class admits a geodesic, shear-free null congruence which is non-twisting but in general diverging and the corresponding solutions in Einstein's theory form the Robinson-Trautman family together with a subset of the Kundt's class. The Robinson-Trautman conditions are found to be frame invariant in string th...

In this paper, a simplified formulation for compositional reservoir simulator is presented. These types of simulators are used when inter-phase mass transfer depends on phase composition as well as pressure. The procedure for solving compositional model equations is completely described. For equilibrium calculation, property estimation Peng Robinson equation of state is used. This equation ...

Densities, structural effects and viscosities of binary nonelectrolyte systems including nitrobenzene + 2-propanol, 2-butanol and 2-pentanol at temperatures (293.15 to 323.15) K and normal atmospheric pressure were measured using an Anton-Paar SVM 3000 stabinger viscometer. Excess molar volumes  and viscosity deviations Δη were calculated and correlated by the Redlich-Kister equation t...

A semi-empirical equation of state has been studied for modelling vapour-liquid data of pure substances. The specific molecular based equation of state is employed here as basis because of its mathematical simplicity. The semi-empirical extension has been accomplished to real fluids by correlating the density dependence of the attraction term to vapour liquid data of a reference fluid. The resu...

The density and viscosity values at T= (293.15 to 323.15) K for binary mixtures of nitromethane with 2-propanol, 2-butanol and 2-pentanol were measured over the entire composition range. From the experimental data, excess molar volumes, thermal expansion coefficients, excess thermal expansions, partial molar volumes at infinite dilution and deviations in viscosity were calculated. The results w...

the density and viscosity values at t= (293.15 to 323.15) k for binary mixtures of nitromethane with 2-propanol, 2-butanol and 2-pentanol were measured over the entire composition range. from the experimental data, excess molar volumes, thermal expansion coefficients, excess thermal expansions, partial molar volumes at infinite dilution and deviations in viscosity were calculated. the results w...

In this paper, we consider the characterization of strong stationary solutions to equilibrium problems with equilibrium constraints (EPECs). Assuming that the underlying generalized equation satisfies strong regularity in the sense of Robinson, an explicit multiplier-based stationarity condition can be derived. This is applied then to an equilibrium model arising from ISO-regulated electricity ...