Thermodynamics and phase diagram calculation of the binary arsenic-tellurium system in the framework of the generalized lattice model

In this work we describe how to efficiently calculate thermodynamic properties and T-x diagram of binary As-Te solution in the generalized lattice model. All the thermodynamic parameters of the As-Te solution are obtained within framework of the generalized lattice model. The binary phase diagram of As-Te system is calculated and good agreement with experimental data is obtained.

Investigation of the Quasi-Binary Phase Diagram FLiNaK-NdF3

The NdF3 solubility in molten eutectic FLiNaK, which is a conceivable medium for a molten salt reactor (MSR), was determined by the quasi-binary phase diagram FLiNaK-NdF3. The eutectic mixture FLiNaK was prepared by direct melting of components LiF, NaF and KF·HF. The acidic anhydrous salt (KF·HF) was used instead of the hygroscopic KF. The NdF3 was sintered by hydrofluorination of Nd2O3. The oxygen impurity in the prepared eutectic FLiNaK, determined by an oxygen analyzer LECO OH836, was 0.036 wt.%, whereas the NdF3 contained 0.04 wt.% of oxygen. A part of the FLiNaK-NdF3 quasi-binary phase diagram was obtained using two thermal analysis techniques: differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The FLiNaK-NdF3 phase diagram in the region of 0–30 mol.% NdF3 contains one eutectic at 2 mol.% NdF3 and 450 °C and two peritectic points: 8 mol.% NdF3 at 500 °C and 22 mol.% NdF3 at 575 °C. The region of the FLiNaK-NdF3 phase diagram below the liquidus line is rather complicated due to the complex structure of the multicomponent system in its molten state, as in its solid state. The NdF3 solubility in FLiNaK is about 5 mol.% at 490 °C and 29 mol.% at 700 °C; this means that the process of the MA transmutation in the MSR can be carried out in molten FLiNaK with a content of actinides as high as 15–20 mol.% in the temperature range of 550–650 °C.

A Computational Method for The Computer Simulation of The Liquid Phase Sintering of Metallic Systems

The growth of solid particles during liquid phase sintering was modeled by the Cellular Automata method. The binary phase diagram and Fickian approach for the diffusion process were applied to simulate the chemical composition variation in liquid and solid phases during sintering. The Oswald-Ripening effect was considered during the dissolution of the solid phase in the liquid phase. It is used to define the probability of solid-phase dissolution by the liquid phase and develop the model to simulate the alloy with solid solubility. So, the microstructure could be modeled in the liquid phase sintering process.

A Continuum Model with Differential Evolution on Binary Phase Diagram of Ionic Surfactant Aqueous Solution

We develop a continuum thermodynamic model basing on the cell model at three perspectives.<br><div><p>First, incorporate the Helfrich free energy as amphiphilic molecules aggregate surface free energy;</p> <p>Second, modify the Poisson-Boltzmann equation by introducing the ion-specic dispersion interaction energy of the counter-ion in aqueous region with the aggregate surface to obtain the concentration distributions of both the surfactant monomer and the counter-ions; <br></p><p>Third, include the temperature dependence of chemical potential for the standard state transition, allowing for calculations on the binary phase diagram of a series of potassium carboxylate as well as of sodium carboxylate soaps. </p><p><br></p><p>The differential evolution algorithm is applied to obtain the global minimum of the required criteria, including the boundary conditions of the electrostatic potential, the optimization of aggregate size with respect to the total free energy and the equilibrium of monomers transferring between the aggregate and aqueous region. The specific-ion effect are presented in the aggregate surface tensions and in the counter-ions distribution within</p> <p>the aqueous regions. The continuum model gives good agreement with the dimension sizes and phase boundaries (lamellar-cylindrical and cylindrical-micellar) which are determined with thermodynamic measurements.</p></div>

A Continuum Model with Differential Evolution on Binary Phase Diagram of Ionic Surfactant Aqueous Solution

We develop a continuum thermodynamic model basing on the cell model at three perspectives.<br><div><p>First, incorporate the Helfrich free energy as amphiphilic molecules aggregate surface free energy;</p> <p>Second, modify the Poisson-Boltzmann equation by introducing the ion-specic dispersion interaction energy of the counter-ion in aqueous region with the aggregate surface to obtain the concentration distributions of both the surfactant monomer and the counter-ions; <br></p><p>Third, include the temperature dependence of chemical potential for the standard state transition, allowing for calculations on the binary phase diagram of a series of potassium carboxylate as well as of sodium carboxylate soaps. </p><p><br></p><p>The differential evolution algorithm is applied to obtain the global minimum of the required criteria, including the boundary conditions of the electrostatic potential, the optimization of aggregate size with respect to the total free energy and the equilibrium of monomers transferring between the aggregate and aqueous region. The specific-ion effect are presented in the aggregate surface tensions and in the counter-ions distribution within</p> <p>the aqueous regions. The continuum model gives good agreement with the dimension sizes and phase boundaries (lamellar-cylindrical and cylindrical-micellar) which are determined with thermodynamic measurements.</p></div>

Peritectic Phase Transition of Benzene and Acetonitrile and Formation of a Cocrystal Relevant to Titan, Saturn’s Icy Moon

Benzene and acetonitrile are two of the most commonly used solvents found in almost every chemical laboratory. Titan, Saturn’s icy moon, is one other place in the Solar system that has even larger amounts of these compounds, together with many other hydrocarbons. On Titan, organic molecules are produced in the atmosphere and carried by methane rainfall to the surface, where they either dissolve in the lakes, deposit as sandy dunes, or solidify as minerals with complex composition and structure. In order to untangle these structural complexities a reliable model of the phase behavior of these compounds at temperatures relevant to Titan is crucial. We therefore report the composition–temperature binary phase diagram of acetonitrile and benzene, and provide a detailed account of the structure and composition of the phases. This work is based on differential scanning calorimetry and in situ powder diffraction analyses with synchrotron X-ray radiation and supported by theoretical modeling. Benzene and acetonitrile were found to undergo a peritectic reaction into a cocrystal with a 1:3 acetonitrile:benzene stoichiometry. The crystal structure was solved and refined in the polar space group, R3, and the solution was confirmed and optimized by energy minimization calculations. To mimic the environment on Titan more accurately, we tested the stability of the structure under liquid ethane. The diffraction data indicate that the cocrystal undergoes further change upon contact with ethane. These results provide new insights into the structure and stability of a potential mineral on Titan, and contribute to the fundamental knowledge of some of the smallest organic molecules