An analytical equation of state by Song and Mason is developed to calculate the PVT properties of mercury. The equation of state is based on the statistical-mechanical perturbation theory of hard convex bodies and can be written as a fifth-order polynomial in the density. There exists three temperature dependent parameters in the equation of state; the second virial coefficient, an effective molecular volume, and a scaling factor for the average contact pair distribution function of hard convex bodies. The temperature-dependant parameters have been calculated using corresponding-states correlations based on the heat of vaporization and the liquid density at the melting point. The average absolute deviation for the calculated density of mercury in the saturation and compressed state is 0.38.

In this paper, we have obtained and presented new relativistic stellar configurations considering an anisotropic fluid distribution with a charge distribution and a gravitational potential ()Zx that depends on an adjustable parameter. The quadratic equation of state based on Feroze and Siddiqui viewpoint is used for the matter distribution. The new solutions can be written in terms of elementary and polynomial functions. We have investigated that the radial pressure, metric coefficients, energy density, anisotropy factor, charge density, mass function have been well defined and are regular in the interior of these new models, which satisfy all physical properties in a realistic star.

A new three parameter equation Of state (EOS) is developed based on well documented data, at three thermodynamic states of the critical point, the normal bubble point and standard condition. Besides these states, the EOS is designed to satisfy the condition of nearly zero Joule-Thomson (JT) coefficients at the normal boiling point. Critical properties and densities at the normal boiling point and a standard condition of more than 100 pure fluids were used. The new EOS is validated using experimental data and eight (8) of the popular EOSs, namely, SRK, PR, LLS, HK, MNM, SW, PT and ALS. The experimental data for pure fluids include 331 data points of vapor pressure covering 12 fluids and compressibility at the critical condition of 23 fluids. For mixtures, the data includes 129 PVT data points of 12 reservoir fluids [seven (7) of them are Sudanese crude oil considered for publication for the first time and five (5) from literature]. The new EOS is found to be superior to the existing EOSs in the prediction of PVT properties of mixtures with a grand average percent absolute deviation (AAPD) of 3.18%. It is also comparable to the existing EOSs in the prediction of vapor pressure despite the fact that existing EOSs are developed based on vapor pressure data; the grand average AAPD is 2.0. In terms of compressibility at the critical point with the exception of LLS, the new EOS yields better results than all other EOSs considered in this work.

The three-parameter Cubic Simplified Perturbed Hard-Chain (CSPHC) equation of state (EOS) developed by Wang and Guo (1993) is improved by applying the classical critical point constraints, modifying the attractive term, and introducing the volume translation technique. All the pure component parameters in the modified CSPHC EOS have been generalized through correlating with molecular weight, specific gravity/acentric factor. The proposed modified CSPHC (CSPHC-M) EOS has been extensively tested on pure substances. Parallel comparison of the vapor pressure and phase density calculation with the original CSPHC, PR-Mathias, PR-Twu and PR equations of state over a wide range of reduced temperature and pressure have been performed. The comparison indicates that CSPHC-M EOS is a reliable theoretical-based tool for engineering calculations.

We developed an equation of state (EOS) proposed by Ihm, Song, and Mason (ISM) for polar fluids. The model consists of four parameters, namely, the second virial coefficient, an effective van der Waals co-volume, a scaling factor, and the reduced dipole moment. The second virial coefficient is calculated from a correlation that uses the heat of vaporization, and the liquid density at the normal boiling point. The reduced dipole moment is calculated from experimental dipole moments data and other parameters were obtained by regressing against saturated liquid density data. In this work, we generalized this equation to calculate the saturated liquid density of n-alkanol, water, and ammonia. The calculated results are also compared with SAFT equation of state and show that the saturated liquid density can be predicted within about 1. 2%.

In the present work, the asymmetric nature of water coexistence curve has been studied by investigating a new scaled crossover parametric equation of state. To do so, the concept of complete scaling [Fisher and Orkoulas, Phys Rev Lett 696, 85 (2000)] has been applied and the critical amplitudes near and far from the critical point have been derived. Also two mixing parameters a3 and b2in the definition of scaling fields in terms of physical fields have been obtained for water. We have shown that mixing of the complete scaling theory and parametric equation of state can explain this nature quite carefully.