Phase equilibrium in electro-magnetic fields

In a recent paper Liu and Müller[1] have derived equilibrium constitutive equations for simple heat conducting fluids in an electro-magnetic field. These results are applied here to find the conditions of phase equilibrium between a liquid and a vapor. An approximate method is proposed for the evaluation of the exact conditions and a numerical example shows the magnitude of the effect the fields have on the phase boundary conditions. A van der Waals fluid is used for the illustration of some ideas.     

Phase equilibrium and nucleation in VLS-grown nanowires

Phase diagrams accounting for capillarity and surface stress in VLS-grown nanowires have been calculated, and linearized forms for the compositions of the solid and liquid are given. The solid-vapor interfacial energy causes a significant depression of the liquidus, and the impurity concentration in the wire decreases with decreasing wire diameter. Nucleation calculations give upper bounds on the nucleation temperature and liquid supersaturation during growth that are consistent with measurements in the Au-Ge system.     

Vapor-liquid equilibrium measurements on benzene + n-decane systems at 298.15 and 323.15 K

Vapor-pressures for benzene + n-decane mixtures have been measured using a static technique. Values for the excess Gibbs energy have been calculated using a modified Barker's method and fitted to a Padé approximant equation. The selection of the most adequate approximant is discussed. Results are compared with those corresponding to other benzene + alkane systems. The value for the activity coefficient of benzene at infinite dilution calculated from these data agrees very well with the values obtained by gas-liquid chromatography.     

Measurement of solubility and density of water + lithium bromide + lithium chloride and water + lithium bromide + sodium formate systems

Solubility of aqueous solutions containing lithium bromide + lithium chloride and lithium bromide + sodium formate were measured (LiBr/NaHCO₂ = 2 and LiBr/LiCl = 2 by mass ratio) at different temperatures. Visual polythermal method was used in the temperature range of (283.15–340.15) K and mass fraction range of (0.4–0.8). Also density of mentioned systems was reported in the temperature range of (288.15–333.15) K. Each set of experimental measurements were correlated using least-square regression as a function of temperature. Our results indicate that solubility of LiBr + LiCl is higher than LiBr and its density is lower than density of aqueous solution of LiBr.     

Thermodynamic equilibrium calculations in cementitious systems

This review paper aims at giving an overview of the different applications of thermodynamic equilibrium calculations in cementitious systems. They can help us to understand on a chemical level the consequences of different factors such as cement composition, hydration, leaching, or temperature on the composition and the properties of a hydrated cementitious system. Equilibrium calculations have been used successfully to compute the stable phase assemblages based on the solution composition as well as to model the stable phase assemblage in completely hydrated cements and thus to asses the influence of the chemical composition on the hydrate assemblage. Thermodynamic calculations can also, in combination with a dissolution model, be used to follow the changes during hydration or, in combination with transport models, to calculate the interactions of cementitious systems with the environment. In all these quite different applications, thermodynamic equilibrium calculations have been a valuable addition to experimental studies deepening our understanding of the processes that govern cementitious systems and interpreting experimental observations. It should be carried in mind that precipitation and dissolution processes can be slow so that thermodynamic equilibrium may not be reached; an approach that couples thermodynamics and kinetics would be preferable. However, as many of the kinetic data are not (yet) available, it is important to verify the results of thermodynamic calculations with appropriate experiments. Thermodynamic equilibrium calculations in its different forms have been applied mainly to Portland cement systems. The approach, however, is equally valid for blended systems or for cementitious systems based on supplementary cementitious materials and is expected to further the development of new cementitious materials and blends.     

Phase equilibrium in the CdSeTlSe system

In the Cd-Tl-Se system the CdSe-TlSe binary join was studied for the first time in detail by DTA, microprobe, x-ray, and microstructure analysis. The phase diagram shows that the section is a classic degenerative eutectic system with no compound formation.     

Nonlinear dielectric effect of critical liquid mixtures: Propylene carbonate + monoalkylbenzene systems

The nonlinear dielectric effect (NDE) is measured in the one-phase region of propylene carbonate + monoalkylbenzene systems. The deviations from the regular molecular behavior are determined by the reference solution method at a very wide temperature distance, up to 180 K, from the critical point. The data are analyzed under the assumption of the universality of the precritical NDE by making use of empirical crossover functions. The precritical NDE anomalies are large. The critical exponent =0.396±0.01 and the correction exponent =1.02±0.1 both differ from the theoretical values.     

Casimir forces in granular and other non equilibrium systems

In this paper we present a method to calculate Casimir Forces for non equilibrium systems with long range correlations. The origin of the force are the fluctuating fields, and the modification that the external, macroscopic objects induce in the spectrum of the fluctuations. The method is first illustrated with a simple model: a reaction-diffusion non-equilibrium system with an structure factor that possesses a characteristic length. The second part of the paper deals with a granular fluid where correlations are long ranged at all scales. In the first case the hydrodynamic fluctuations are confined by two plates, while in the second one the confinement comes from two immobile large and heavy particles. In both cases Casimir forces are calculated, and their properties analyzed.     

包装印刷过程中的水墨平衡

平板印刷由于印刷质量好、成本低,而受到业内人士的喜爱.所以,平板印刷在行业中占有相当大的比例.     

Phase equilibrium and PVT-properties of 0.7223H2O + 0.1242 n-C6 H14 + 0.1535 n-C3H7OH ternary system

The results are given of experimental investigation of the PVT-properties and liquid-liquid and liquid-vapor phase equilibria of 0.7223H₂O + 0.1242 n-C₆ H₁₄ + 0.1535 n-C₃H₇OH ternary system along six different isochores. The measurements are performed by the constant-volume piezometer technique in the range of temperature from 309.26 to 678.82 K, density from 81.0 to 485.0 kg/m³, and pressure up to 60 MPa. The behavior of the system in the vicinity of the liquid-liquid and liquid-vapor critical points is treated using the scaling equations. The PVT-properties are described by the Peng-Robinson equation.Translated from Teplofizika Vysokikh Temperatur, Vol. 43, No. 1, 2005, pp. 045–050. Original Russian Text Copyright © 2005 by S. M. Rasulov and A. R. Rasulov.     

Phase equilibrium,microstructure and properties of some magnesite-chromite refractories

The effect of phase equilibrium and microstructure of magnesite-chromite batches containing from 0 to 100% Egyptian chrome ore, with intervals of 10%, on their physical properties was studied. The phase equilibrium data were calculated using the phase relationships within the system M-M₂S-CMS-MR (M=MgO, S=SiO₂, C=CaO, R=R₂O₃). A computerized electron-probe microanalyser was applied to study the microstructure as well as microchemistry of the fired magnesite-chromite co-clinkers. Some physical and technological properties of the co-clinkered briquettes were also investigated by determining densification parameters, spalling resistance and load-bearing capacity.It is concluded that dense, spalling resistant and refractory magnesite, magnesite-chrome and chrome-magnesite refractories could be produced by co-clinkering of magnesite-chromite batches of 1000, 7030 and 3070 weight ratios, respectively, at 1600 °C. The prepared co-clinkers were subsequently graded, moulded and refired up to 1700 °C in order to obtain direct-bonded bricks. Meanwhile, dense chromite refractories with lower refractory quality could be processed by firing the Egyptian chrome ore up to 1600 °C.     

Phase equilibrium and interphase transition layer as an ordering problem

The model of a binary ordering alloy, developed previously based on the conventional distribution method, is used for describing spatially inhomogeneous multiphase equilibrium systems of gas-solid, liquid-gas or crystal-liquid types, including the structure of an interphase transition layer. General results are illustrated by specific predictions for a two-phase crystal-gas system.Academic Scientific Complex A. V. Luikov Heat and Mass Transfer Institute of the Belarussian Academy of Sciences, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 2, pp. 198–206, August, 1993.     

Thermodynamics of Cr3+-Cr6+ equilibrium in borate melts

The Cr³⁺-Cr⁶⁺ equilibrium was studied in lithium and sodium aluminoborate melts in an air atmosphere at different temperatures. A mechanism of the Cr³⁺-Cr⁶⁺ redox reaction in glass melts has been suggested. Enthalpy and entropy of the reaction in molten borates were calculated and the results thus obtained have been discussed thermodynamically.     

Direct computation of critical equilibrium states for spatial beams and frames

In this paper, explicit formulas for second order derivatives of the residual vector with respect to the state variables for a geometrically exact 3D beam element based on the Reissner's model are presented. These derivatives are required when a direct non‐linear stability eigenvalue problem is solved by the Newton's method. If the external load is parametrized by a single parameter, such an eigenvalue problem consists of solving the critical state variables, the eigenmode, and the critical load parameter from the equation system consisting of the equilibrium equations, the criticality condition, and some auxiliary conditions depending on the type of a critical point. Copyright ©2011 John Wiley & Sons, Ltd.     

Phase multistability in quasiperiodically driven systems

The influence of quasiperiodic driving on phase multistability in coupled Feigenbaum oscillators is investigated. Various new effects associated with strange nonchaotic attractors are observed. Pis’ma Zh. Tekh. Fiz. 25, 49–56 (November 26, 1999)     

Phase relations in the Pr-Fe-Sb and Pr-Co-Sb systems

The phase relations in the Pr-Fe-Sb and Pr-Co-Sb systems have been studied, and the 600°C sections of their phase diagrams have been constructed. In the Pr-Fe-Sb system, the three earlier known ternary compounds PrFe₄Sb₁₂, PrFeSb₂, and Pr₆Fe₁₃Sb have been obtained, and two new antimonides have been identified: PrFeSb₃ (sp. gr. Pbcm, CeNiSb₃ structure, a = 1.251(8) nm, b = 0.606(4) nm, c = 1.848(9) nm) and Pr₅Fe₂Sb (sp. gr. I4/mcm, Mo₅B₂Si structure, a = 0.7541(2) nm, c = 1.4161(2) nm). In the Pr-Co-Sb system, the existence of the compound PrCo_1?x Sb₂ has been confirmed, and two new antimonides have been identified: PrCoSb₃ (sp. gr. Pbcm, CeNiSb₃ structure, a = 1.2673(4) nm, b = 0.6127(2) nm, c = 1.8129(7) nm) and Pr₅CoSb₂ (sp. gr. Pnma, Y₅Ni_xSb_3?x -related structure, a = 1.2476(2) nm, b = 0.9088(1) nm, c = 0.8104(1) nm).     

Phase relations in the Nb-Cr-Sb and Nb-Mn-Sb systems

The 970-K phase relations in the Nb-Cr-Sb and Nb-Mn-Sb systems have been studied by X-ray diffraction. The systems contain no ternary compounds. There are substitutional solid solutions based on binary antimonides. The Nb₅Sb₄-based solid solution (Ti₅Te₄ structure) extends to the composition Nb_4.1Mn_0.9Sb₄; the Nb₃Sb-based solid-solution series (Cr₃Si structure) is bounded by the compositions Nb_2.6Cr_0.4Sb and Nb_2.4Mn_0.6Sb; the Cr_{1.04 − x} Sb_{0.96 + x} -based solution with x = 0.08 (NiAs structure) exists between the compositions Cr_0.94Nb_0.10Sb_0.96 and Cr_0.70Nb_0.30Sb_1.00; and the Mn_{1.00 + x} Sb_{1.00 − x} -based solution with x = 0.1 extends to the composition Mn_0.9Nb_0.2Sb_0.9. In addition, there is an interstitial solid solution (Ni₂In structure), which extends to MnNb_0.25Sb. The 970-K isothermal sections of the Nb-Cr-Sb and Nb-Mn-Sb phase diagrams are mapped out in the region 0–80 at % Sb.     

Phase relations in the Nb-Sb-Si and Nb-Sb-P systems

Phase relations in the systems Nb-Sb-Si (0–70 mol % Sb) and Nb-Sb-P (0–50 mol % P) have been studied by X-ray diffraction, and the 1070-K isothermal sections of their phase diagrams have been constructed. The existence of the compound NbSbSi (PbFCl structure) has been confirmed. Both systems contain a few substitutional solid-solution series: Nb₃(Sb,Si) and Nb₃(Sb,P) (Cr₃Si structure, limiting compositions Nb₃Sb_0.55Si_0.45 and Nb₃Sb_0.8P_0.2), Nb₃(Si,Sb) and Nb₃(P,Sb) (Ti₃P structure, limiting compositions Nb₃Si_0.6Sb_0.4 and Nb₃P_0.5Sb_0.5), Nb(P,Sb) (NbAs structure, limiting composition NbP_0.8Sb_0.2), and Nb(Si,Sb)₂ (CrSi₂ structure, limiting composition NbSi_1.65Sb_0.35). Phase equilibria in related systems are analyzed.     

Equation-of-state calculations of chemical reaction equilibrium in nonideal systems

In order to calculate accurately chemical-reaction equilibria of a system over a wide range of temperatures and pressures, one must account for the non-idealities of the system. In this work, a method is developed to predict accurately chemical-reaction equilibria and phase equilibria of a system using an equation of state to account for the nonidealities. The general formalism for a multicomponent system with multiple reactions is presented. Three widely used cubic equations of state are used to calculate the physical properties of the species. The proposed method is applied to the water-gas shift reaction, to the decomposition of methylcyclohexane, and to the reaction of carbon monoxide with hydrogen sulfide over a wide range of temperatures and pressures.