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A theoretical model of a cold and dense isolated solar prominence is presented. The thermodynamic parameters of a filament (gas pressure, density and temperature) are calculated from a specified magnetic field structure. The filament lies above the photospheric polarization separation line and its magnetic field falls off rapidly with distance from the axis, so that the total electric current along the axis of the filament equals zero. The prominence has a helical magnetic field structure divided into separate thin filaments. The density and temperature distributions of the prominence derived from the equilibrium conditions for this kind of magnetic field correspond well to the known observed parameters.

In close to equilibrium conditions (1° per 400 min), the DSC measurements demonstrated that the melting parameters of white rat sarcoma M1 procollagen equaled to Tm = 34.4 °C and ΔTm = 2.7°, and the same parameters of fibers reconstructed from those solutions of procollagen were Tm = 38.5 °C and ΔT = 3.1°. These values were by 1.0° lower and 0.8° wider, and by 1.7° lower and 0.7° wider in comparison with the parameters of procollagen and fibers of healthy rat tissue, accordingly. The simultaneous increase in melting temperature and melting width, and a weak decrease in melting enthalpy demonstrated that sarcoma M1 procollagen had some defects. The considerable decrease by 7° in melting temperature and decrease in thermostability of procollagen fibrils in case of sarcoma M1 in comparison to the healthy norm gives a good prospective potential of using this approach as a quick DSC test to detect various sarcomas, including human sarcomas, by comparing the biopsy material or postsurgical tissues with the normal samples.

The problem on the injection of a cold gas into a snow mass partially saturated with this gas, accompanied by hydrate formation, was solved numerically. The case where the rate of hydrate formation is limited by the diffusion of the gas through the hydrate layer, formed between the gas and ice phases, to the ice–hydrate contact boundary was considered. The formation of a hydrate by the equilibrium scheme, in accordance with which the state of the initial gas–snow system changes in the process of injection of a gas into it in line with the phase-equilibrium curve of the gas–snow–hydrate system, was investigated. It was established that, in the case of complete transformation of the show in a snow mass into the hydrate state in the process of hydrate formation in it under equilibrium conditions, in the snow mass there appears a moving boundary separating it into two zones: a zone saturated with the gas and the hydrate and a zone in which snow, the gas, and the hydrate are present at the same time.

The thermodynamic and radiative properties of TiO in the local thermodynamic equilibrium (LTE) and non-LTE (NLTE) were investigated. Firstly, we investigated the potential energy curves of fifteen ...

The formation of gaseous (gas) hydrates for storage, separation and transportation application is essential. In this regard, a comprehensive study of this case is essential. Semi-clathrate hydrates have higher temperature stability and are formed in a stable range. The purpose of this study is review the experimental and modeling of the semi-clathrate hydrates, to investigate the equilibrium conditions for the formation/dissociation of them based on the type of thermodynamic promoters like TBAB, TBAC, TBAF, TBANO3 and TBP groups. This review is consist of 4 overall section, at first an introduction to semi-clathrate hydrates has defined. After that, the experimental research has discussed through different gas systems such as CO2, CH4, N2, H2 etc. Also, the target of each study, like the CO2 capture, separation of CH4, formation/dissociation equilibrium conditions, are expressed. Then, in the modeling section, the different types of thermodynamic modeling like, equaling fugacity, intelligence computing, Gibbs free energy minimization and Chen-Guo method are collected. At final section, a comparison between types of promoter showed that the addition of TBAF to aqueous solution has the best promotion effect on the CO2 clathrate hydrate formation. Also, the results of comparing the concentration of promoters have shown that up to a certain amount of TBAB, the salt's role as a promoter and by addition concentration of promoter, has an inhibition effect. Also, besides the results of the comparison different promoters on equilibrium conditions of different gaseous hydrates, have indicated that, TBAB has the most significant impact on carbon dioxide hydrate.

A device that generates exotic fluids of particles at equilibrium conditions and high temperatures could have applications ranging from low-loss electrical cables to memory storage. Possible superfluid state created with a neat set-up.

The mechanical strength of a polycrystalline material can be drastically weakened by a phenomenon known as grain boundary (GB) premelting that takes place, owing to the so-called disjoining potential, when the dry GB free energy $$\sigma _{gb}$$ σ gb exceeds twice the free energy of the solid–liquid interface $$\sigma _{sl}$$ σ sl . While previous studies of GB premelting are all limited to equilibrium conditions, we use a multi-phase field model to analyze premelting dynamics by simulating the steady-state growth of a liquid layer along a dry GB in an insulated channel and the evolution of a pre-melted polycrystalline microstructure. In both cases, our results reveal the crucial influence of the disjoining potential. A dry GB transforms into a pre-melted state for a grain-size-dependent temperature interval around $$T_m$$ T m , such that a critical overheating of the dry GBs over $$T_m$$ T m should be exceeded for the classical melting process to take place, the liquid layer to achieve a macroscopic width, and the disjoining potential to vanish. Our simulations suggest a steady-state velocity for this transformation proportional to $$\sigma _{gb} -2 \sigma _{sl}$$ σ gb - 2 σ sl . Concerning the poly-crystalline evolution, we find unusual grain morphologies and dynamics, deriving from the existence of a pre-melted polycrystalline equilibrium that we evidence. We are then able to identify the regime in which, due to the separation of the involved length scales, the dynamics corresponds to the same curvature-driven dynamics as for dry GBs, but with enhanced mobility.

Dielectric relaxation of ceria nanocrystals under biased condition for different grain sizes was in this study evaluated in modulus formalism using impedance spectroscopy. Prior to the impedance measurements, the ceria sample was calcined at 200 °C for 30 min and pressed into cylindrical pellets with 8 mm diameter and 1 mm thick by applying uniaxial four-ton pressure using a hydraulic press. This was then sintered at 300 °C, 450 °C, 600 °C and 900 °C for 30 min. Systematic analysis of modulus formalism data using commercial Z-view and Z-plot software's permitted, reliable extraction of dielectric relaxation time (τ) of ceria nanocrystals. The observed dielectric relaxation time (τ) at equilibrium condition varied from 10–5 to 10–3 s when the grain size of ceria nanocrystals was increased from 9 nm to 29 nm. But when the DC bias voltage was applied, the same dielectric relaxation time (τ) was tuned to ∼10–4 s for all the grain sizes of ceria nanocrystals, because of Schottky grain boundary potential barrier height (φb) suppression.

The recently developed non-equilibrium self-consistent generalized Langevin equation theory of the dynamics of liquids of non-spherically interacting particles [2016 J. Phys. Chem. B 120 7975] is applied to the description of the irreversible relaxation of a thermally and mechanically quenched dipolar fluid. Specifically, we consider a dipolar hard-sphere liquid quenched (at t w = 0) from full equilibrium conditions towards different ergodic–non-ergodic transitions. Qualitatively different scenarios are predicted by the theory for the time evolution of the system after the quench (t w > 0), that depend on both the kind of transition approached and the specific features of the protocol of preparation. Each of these scenarios is characterized by the kinetics displayed by a set of structural correlations, and also by the development of two characteristic times describing the relaxation of the translational and rotational dynamics, allowing us to highlight the crossover from equilibration to aging in the system and leading to the prediction of different underlying mechanisms and relaxation laws for the dynamics at each of the glass transitions explored.

Studying liquid transition to other states of matter encounters certain challenges. The phase transition containing a liquid phase embodies energetic change that can be quantitatively correlated to the equilibrium conditions. The challenges can be more complex if the liquid is geometrically confined in a narrow space in which the energetic interaction between the confinement and confined liquid might become more pronounced. Therefore, it is of great essence to probe the enthalpic perspective of an equilibrium in which at least one liquid phase exists. However, the challenges can be used as opportunities to characterize both the confined liquid as well as the confinement material in terms of phase transition, intermolecular interaction, and pore size distribution. In this article, enthalpic studies of liquid phase equilibrium are carefully discussed. The majority of the discussions address the confined thermodynamic equilibrium that includes a liquid phase, especially the liquid phase transition under confinement to and from vapor and solid phases is elaborated in great details. In addition, enthalpic overviews of bulk equilibrium of liquids are briefed where challenges and opportunities to calorimetrically study these equilibrium states are remarked. An integrative and instructive approach is closely followed in order establish a network of information that can be used not only for comprehensively reviewing the existing state-of-the-art, but also for providing invaluable insight and constructive inputs for future studies to bridge the gaps in the field.

Previous studies of the responses of shape memory alloys (SMA) under a rapid heat pulse revealed the existence of a critical plateau stress that determines the performances of high rate SMA actuators. In this letter, we investigate the effects of temperature and initial stress on the plateau stress. Calculations based on the integration of the Clausius-Clapeyron equation while considering the inhomogeneity of the transformation temperature were in good agreement with the measured data. Our results indicate that the plateau stress represents equilibrium conditions and that actuation performances can be increased significantly by increasing the initial stress.

This article summarizes the results from a decade of research which began following a serendipitous discovery and continued with a systematic, Edisonian approach. During the serendipitous stage, there were indications of very-high- $$T_\mathrm{c}$$ superconductivity (at about 200–250 K) detected in laser-treated samples of doped strontium ruthenates. The synthesis route that had been used was strongly out of equilibrium. In spite of our intense studies, later, synthetic efforts along a route closer to equilibrium conditions did not reveal high- $$T_\mathrm{c}$$ superconductivity in the new samples, though there were indications of low- $$T_\mathrm{c}$$ superconductivity. Before the arrival of results on nonequilibrium synthetic routes, it is an appropriate time to summarize the results found within the equilibrium routes, analyze potential corollaries of the complex structure of samples within our initial findings, and discuss the next steps of research.

In this experimental study, the phase boundary behavior of CO2 hydrate is reported in the presence of 1, 5, and 10 wt% of three aqueous ammonium based ionic liquids (AILs) solutions. The T-cycle technique is used to measure the hydrate equilibrium conditions of AILs + CO2 + H2O hydrate systems within the ranges of 274–283 K and 1.80–4.20 MPa. All studied AILs inhibited CO2 hydrate with the inhibition effect increasing with AILs concentration. The 10 wt%, TEAOH showed the highest inhibition effect with an average suppression temperature (∆ Ŧ) of 1.7 K, followed by TMACl (∆ Ŧ = 1.6 K) and then TPrAOH (∆ Ŧ = 1.2 K). Furthermore, COSMO-RS analysis is performed to understand the molecular level inhibition mechanism of AILs. In addition, the enthalpies of hydrate dissociation for all studied systems are also determined. The calculated hydrate dissociation enthalpies revealed that all the studied AILs show insignificant participation in CO2 hydrate cage formation at all concentrations, hence, do not form semi-clathrate hydrates.

Glycerol acetates are sustainable products that exhibit several industrial applications. These compounds are traditionally synthesized by the esterification of glycerol with acetic acid, and their fractionation is key to isolate high value-added products. The supercritical fractionation of glycerol acetates is an interesting alternative to separate efficiently these low volatile viscous mixtures at low temperatures to avoid thermal degradation. In this work, we investigate the CO2 fractionation of a commercial mixture of glycerol acetates. Experimental fractionations under equilibrium conditions are carried out at temperatures between 301 K and 323 K and pressures between 100 bar and 130 bar. Moreover, we model the extractions with the GCA-EOS, which in a previous work, predicted that it would be technically feasible to fractionate the glycerol acetate mixture using CO2. In this work, we show that the GCA-EOS is a useful tool to design and optimize the scaled-up separation process. Fil: Fortunatti Montoya, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina Fil: Sánchez, Francisco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina Fil: Hegel, Pablo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina Fil: Pereda, Selva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina

Infrastructure materials, such as rocks and concrete, exhibit an array of intricate and interrelated dynamic mechanical behaviors that act across a broad range of size scales. Modeling these dynamic behaviors is important for understanding safe design, application, and maintenance practices. One particular and fascinating nonlinear dynamic mechanic response - slow dynamics - is characterized by a self-recovering hysteretic stress-strain relationship. Here we formulate a mechanistic model for slow dynamics, which we call a mechanistic diffusion model (MDM), based on coupled mechanical and diffusional processes. Diffusion-driven moisture migration nearby the minuscule regions surrounding granular contact points within a cracked solid serves as the physical foundation of the model. Diffusion physics explains fast conditioning rates, as moisture is vaporized, and relatively slow recovery process rates, as the moisture condenses back to equilibrium conditions. The MDM provides physically-based justification for environment and strain activated observations noted in previous slow dynamic experiments. The MDM is verified against new experimental data of internal humidity and mechanical softening observed in a porous solid during dynamic excitation. The MDM model predicts, and the accompanying experiment successfully exhibits, internal humidity changes with slow dynamic nonlinearity of the test material. The MDM model identifies a physical mechanism of transient nonlinearity and provides a framework to interpret the significance of observed slow dynamic nonlinear behaviors.

Equilibrium conditions of many chemical and physical processes can be determined from minimization of the Gibbs free energy of the system. Suitable closed-form representations of the Gibbs free energy and entropy of hydrogen sulfide remain unsolved in the communality of science and engineering. Here we report two suitable closed-form representations for the Gibbs free energy and entropy of hydrogen sulfide, which involve merely six molecular constants of the hydrogen sulfide molecule, whereas the conventional computation models require a great many experimental spectroscopy data. In the temperature range from 300 to 6000 K, the average relative deviations of the predicted molar Gibbs free energy and entropy values from the National Institute of Standards and Technology database are 0.185% and 0.191%, respectively. Our study presents a novel pathway of predictions of thermodynamic properties for highly toxic hydrogen sulfide.

Equilibrium conditions of droplets on deformable substrates are investigated, and it is proven using Jacobi's sufficient condition that the obtained solutions really provide equilibrium profiles of both the droplet and the deformed support. At the equilibrium, the excess free energy of the system should have a minimum value, which means that both necessary and sufficient conditions of the minimum should be fulfilled. Only in this case, the obtained profiles provide the minimum of the excess free energy. The necessary condition of the equilibrium means that the first variation of the excess free energy should vanish, and the second variation should be positive. Unfortunately, the mentioned two conditions are not the proof that the obtained profiles correspond to the minimum of the excess free energy and they could not be. It is necessary to check whether the sufficient condition of the equilibrium (Jacobi's condition) is satisfied. To the best of our knowledge Jacobi's condition has never been verified for any already published equilibrium profiles of both the droplet and the deformable substrate. A simple model of the equilibrium droplet on the deformable substrate is considered, and it is shown that the deduced profiles of the equilibrium droplet and deformable substrate satisfy the Jacobi's condition, that is, really provide the minimum to the excess free energy of the system. To simplify calculations, a simplified linear disjoining/conjoining pressure isotherm is adopted for the calculations. It is shown that both necessary and sufficient conditions for equilibrium are satisfied. For the first time, validity of the Jacobi's condition is verified. The latter proves that the developed model really provides (i) the minimum of the excess free energy of the system droplet/deformable substrate and (ii) equilibrium profiles of both the droplet and the deformable substrate.

High temperature confocal microscopy (using cooling rates of 1 and 20 °C s−1) has been used in conjunction with segregation modeling (for cooling rates of 0.1–100 °C s−1) to understand the implications that high cooling rates, representative of that seen for belt casting, has on compositional inhomogeneity and precipitation in high strength low alloy steels. Due to the increased level of segregation (and reduced back diffusion) precipitates are predicted, and shown, to form in the interdendritic solute rich regions at temperatures higher than would be expected under equilibrium conditions at the higher cooling rate. This results in a larger volume fraction of precipitates in samples held at 1000 °C after being cooled at 20 °C s−1 compared to those cooled at 1 °C s−1.

The grain boundary (GB) wetting by the melt and second solid phase has been studied in the Sn–Pb system both in equilibrium conditions and during continuous strain. The percentage of Sn/Sn GBs completely wetted by the melt increases from 80% at eutectic temperature Te=183 °C to 100% at 220 °C. The percentage of Pb/Pb GBs completely wetted by the melt increases from 0% at Te to 100% at 270 °C. Below Te only incomplete wetting of Pb/Pb GBs by solid Sn and Sn/Sn GBs by solid Pb has been observed after long annealing. However, during strain the lattice dislocations are continuously absorbed by GBs increasing the GB energy. As a result, the complete wetting of such non-equlibrium Sn/Sn GBs by the second solid phase Pb appears. Therefore, the difference in energies between equilibrium and non-equilibrium grain boundaries has been experimentally demonstrated for the first time.

This paper studies the effects of chemical, elastic and interfacial energies on the equilibrium morphology of misfit particles due to phase separation in binary alloys under chemo-mechanical equilibrium conditions. A continuum framework that governs the chemo-mechanical equilibrium of the system is first developed using a variational approach by treating the phase interface as a sharp interface endowed with interfacial excess energy. An extended finite element method (XFEM) in conjunction with the level set method is then developed to simulate the behaviors of the coupled chemo-mechanical system. The coupled chemo-mechanics model together with the numerical techniques developed here provides an efficient simulation tool to predict the equilibrium morphologies of precipitates in phase separate alloys.

Studies were carried out systematically on a series of Al-8.5 wt pct Zn-xMg-yCu alloys (x is about 1.5, 2.0, and 2.5 wt pct, and y is about 1.5, 2.0, 2.5, and 2.9 wt pct). The effects of alloying elements Mg and Cu on the microstructures of as-cast and homogenized alloys were investigated using the computational/experimental approach. It shows that Mg(Zn,Al,Cu)2 (σ) phase can exist in all the as-cast alloys without any observable Mg32(Al,Zn)49/Al2Mg3Zn3 (T) or Al2CuMg (S) phase, whereas Al2Cu (θ) phase is prone to exist in the alloys with low Mg and high Cu contents. Thermodynamic calculation shows that the real solidification paths of the designed alloys fall in between the Scheil and the equilibrium conditions, and close to the former. After the long-time homogenization [733 K (460 °C)/168 hours] and the two-step homogenization [733 K (460 °C)/24 hours + 748 K (475 °C)/24 hours], the phase components of the designed alloys are generally consistent with the calculated phase diagrams. At 733 K (460 °C), the phase components in the thermodynamic equilibrium state are greatly influenced by Mg content, and the alloys with low Mg content are more likely to be in single-Al phase field even if the alloys contain high Cu content. At 748 K (475 °C), the dissolution of the second phases is more effective, and the phase components in the thermodynamic equilibrium state are dominated primarily by (Mg + Cu) content, except the alloys with (Mg + Cu) ≳ 4.35 wt pct, all designed alloys are in single-Al phase field.

The development of Langevin models for molecular dynamics represents a promising approach to deal with the cost issue of Boltzmann equation solutions. A recent paper of Zhang et al. suggested to study the Prandtl number variability of such molecular Langevin models under equilibrium conditions. This paper comments on several questions related to the approach of Zhang et al. First, a correction is presented for the Green–Kubo minimum Prandtl number derived by Zhang et al. Second, the relationship between the Green–Kubo Prandtl number and a Prandtl number defined in the Boltzmann equation sense is analytically explained. Third, based on this relationship it is shown that the consideration of a Prandtl number defined in the Boltzmann equation sense represents a more appropriate approach to address the question considered.

In this note the phenomena of formation of grain bulbs (compact grain structure) in presence of grains with different size is discussed from point of view of grain force balance. The requirement is found showing where in the equilibrium conditions the larger size grains are expelled from the regions of smaller size grains forming dust bulbs containing only the smallest size grains. The experiments where this phenomenon was observed are discussed. It is possible to conclude that these experiments can serve as direct evidence for existence of the non-linear screening of individual grains and for excitation of collective large scale electric fields that balances the drag forces in domain of structures. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We report a numerical test of the Adam–Gibbs relation for the TIP4P/2005 model of water. The configurational entropy is here evaluated as the logarithm of the number of different basins in the potential energy landscape sampled in equilibrium conditions. Despite the non-monotonic behaviour which characterise the density dependence of the diffusion coefficient, the Adam–Gibbs relation is satisfied within the numerical precision in a wide range of densities and temperatures. We also show that expressions based on the excess entropy (the logarithm of the number of sampled microstates in phase space) fail in the region of densities where a tetrahedral hydrogen bond network develops., GRAPHICAL ABSTRACT

The two-dimensional inviscid incompressible steady flow past an inclined flat plate is considered. A locus of asymmetric equilibrium configurations for vortex pairs is detected. It is shown that the flat geometry has peculiar properties compared to other geometries: (i) in order to satisfy the Kutta condition at both edges, which ensures flow regularity, the total circulation and the force acting on the plate must be zero; and (ii) the Kutta condition and the free vortex equilibrium conditions are not independent of each other. The non-existence of symmetric equilibrium configurations for an orthogonal plate is extended to more general asymmetric flows.

The microstructure and phase composition of alloys Al-Cu-Fe in as-cast state and after heat treatment at different temperatures were investigated. The presence of a quasicrystalline phase Al65Cu20Fe15 which coexists with crystalline phases in as-cast condition is found. The formation of single quasicrystalline phase composition in Al - 40 wt.% Cu - 17 wt.% Fe alloy after annealing at 800 °C for 100 hours is established. After heat treatment, i.e. closer to equilibrium conditions, the quasicrystalline phase Al65Cu20Fe15 is transformed into quasicrystalline phase Al13Cu4Fe3 with more complicated lattice.

In this study, we perform a series of mass-balance-type calculations, in order to estimate the minimum volume of liquid water required to dissolve completely a single methane gas bubble, located in...

In this paper, we develop a dynamic decision model of transboundary basin pollution with emission permits trading and pollution abatement investment. In our model, the stock of pollution abatement evolves according to the standard capital accumulation dynamics equation, the emission permits are bought or sold at price which is be determined by the equilibrium conditions of the permit market. The main objective of this paper is to explore the optimal levels of pollution emission and emission abatement investment under the regions’ non-coalition and coalition strategies, such that the discounted stream of regions’ net revenues is maximized. Our results show that (i) the upstream coalition can help the upstream region to increase the pollution abatement investment and decrease the pollution emission; (ii) in contrast, the downstream coalition can help the midstream region to increase the pollution abatement investment and decrease the pollution emission

Green's function for isotropic thermoelastic two-phase infinite body under a point heat source is established in this paper. By virtue of the compact general solution compact which is expressed in harmonic functions, six new suitable harmonic functions with undetermined constants are constructed for the two semi-infinite bodies of two-phase infinite body. The corresponding thermoelastic field can be obtained by substituting these harmonic functions into the general solutions. And the undetermined constants can be obtained by the equilibrium conditions and compatibility conditions for both perfectly bonded interface and smooth contact interface. Numerical results are given graphically by contours.

A debated issue, in applications of Eringen 's nonlocal model of elasticity to nanobeams, is the paradox concerning the solution of simple beam problems, such as the cantilever under end-point loading. In the adopted nonlocal model, the bending field is expressed as convolution of elastic curvature with a smoothing kernel. The inversion of the nonlocal elastic law leads to solution of a Fredholm integral equation of the first kind. It is here shown that this problem admits a unique solution or no solution at all, depending on whether the bending field fulfils constitutive boundary conditions or not. Paradoxical results found in solving nonlocal elastostatic problems of simple beams are shown to stem from incompatibility between the constitutive boundary conditions and equilibrium conditions imposed on the bending field. The conclusion is that existence of a solution of nonlocal beam elastostatic problems is an exception, the rule being non-existence for problems of applicative interest. Numerical evaluations reported in the literature hide or shadow this conclusion since nodal forces expressing the elastic response are not checked against equilibrium under the prescribed data. The cantilever problem is investigated as case study and analytically solved to exemplify the matter.

Thermodynamic models based on the van der Waals–Platteeuw statistical theory (Adv. Chem. Phys. 2, 1 (1959)) can be very accurate in describing hydrate equilibrium conditions, even for some occasions when multiple cavity occupancy occurs. These are cases outside the range of assumptions used for the development of the original statistical theory. However, during multiple cavity occupancy such models can perform poorly when calculating the cavity occupancies. This paper reports novel Grand Canonical Monte Carlo molecular simulations for the case of pure structure II N2 hydrate and compares the calculated cavity occupancies with experimental data and observe reasonable agreement. Also examined are the van der Waals–Platteeuw-based modifications that retained the single-occupancy assumption of the original theory and how they perform when predicting cavity occupancies and hydrate equilibrium pressures.

Penetration of distilled water into a clay soil sample saturated by a sodium chloride solution is experimentally studied. Changes in filtration characteristics of soil due to penetration of fresh water and swelling of clay particles, as well as due to the action of an electrical field on the replacement process are quantified. It is demonstrated that electrokinetic processes play a key role at the final stage of replacement of the solution by fresh water. Reasons for the emergence of clay self-polarization potentials owing to violation of electrical equilibrium conditions are studied.

Monte Carlo simulations were performed to investigate the mechanisms of glass dissolution as equilibrium conditions are approached in both static and flow-through conditions. The glasses studied are borosilicate glasses in the compositional range (80 − x)% SiO2 (10 + x / 2)% B2O3 (10 + x / 2)% Na2O, where 5

Extraction of vanadium(IV) from sulphate acid solution was studied using organophosphorous-based extractants D2EHPA, EHEHPA and CYANEX 272 in kerosene. The different parameters affecting the extraction of vanadium(IV) under equilibrium conditions were separately investigated to elucidate the stoichiometry of the extracted species. The distribution ratio of vanadium increased with increasing equilibrium pH of the aqueous phase, concentration of the extractants and temperature. D2EHPA was found to be a stronger extractant, having greater pH functionality than EHEHPA and CYANEX 272. Extraction of vanadium(IV) by these organophosphorous-based extractants involved cation exchange mechanism, and the extracted species appear to be VOR2(HR)2 in the low equilibrium pH and VOR2 in the higher equilibrium pH, where HR refers to the three acidic extractants.

The equilibrium conditions of four duplex stainless steels; Fe-23Cr-4.5Ni-0.1N, Fe-22Cr-5.5Ni-3Mo-0.17N, Fe-25Cr-7Ni-4Mo-0.27N and Fe-25Cr-7Ni-4Mo-1W-1.5Cu-0.27N were studied in the temperature reg ...

We have performed first principles density functional theory calculations to study the formation energy of point defects in TiC, TiO and TiCO compounds. The formation energy of isolated vacancies were obtained for different equilibrium conditions. For binary compounds, we have also calculated the formation energy of antisite defects. It was found that the defect formation energies strongly depend on the chemical environment. Our results show that C vacancies are easily formed in TiC and TiCO. For the TiO compound, Ti vacancies are highly probable to occur and O vacancies are also easily formed under titanium rich atmosphere., Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência , Tecnologia, Inovação” – CONC-REEQ/443/EEI/2005, POCTI/CTM/69362/2006

The fabrication of solar cell grade silicon (SOG-Si) feedstock involves processes that require direct contact between solid and liquid phases at near equilibrium conditions. Knowledge of the phase diagram and thermochemical properties of the Si-based system is therefore important for providing boundary conditions in the analysis of processes. A self-consistent thermodynamic description of the Si-Ag-Al-As-Au-B-Bi-C-Ca-Co-Cr-Cu-Fe-Ga-Ge-In-Li-Mg-Mn-Mo-N-Na-Ni-O-P-Pb-S-Sb-Sn-Te-Ti-V-W-Zn-Zr system has recently been developed by SINTEF Materials and Chemistry. The assessed database has been designed for use within the composition space associated with SoG-Si materials. The thermochemical database has further been extended to calculate the surface tensions of liquid Si-based melts. In addition to thermochemical and phase equilibrium calculation, several surface-related properties (temperature and composition gradients, surface excess quantity etc.) are able to simulate simultaneously using the database. The databases can be regarded as the state-of-art equilibrium relations in the Si-based multicomponent system.

The site percolation problem on square lattices whose sites are grouped in two types of energetically different patches is studied. Several lattices formed by collections of either randomly or orderly localized and no overlapped patches of different sizes are generated. The system is characterized by two parameters, namely, the size of each patch, l , and the energy difference between the two kind of sites, Δ E . Particles are adsorbed at equilibrium on the lattice. The critical coverage is determined by means of Monte Carlo simulations and finite-size scaling analysis. The percolative behavior of the system as a function of the parameters characterizing the heterogeneity of the energetic surface topography is presented and discussed.

Thermal impedance measurement of semiconductor devices is much easier to perform experimentally when heating and measuring phases are performed separately in order to avoid mutual interference. However, unless we are able to guarantee that the system is in thermal equilibrium before performing the measurement, the result is not consistent with the definition of thermal impedance. This work presents a method to extend the validity of a measurement made under non-equilibrium conditions to fit the real value of thermal impedance, under the assumption that the system is linear or has negligible nonlinearity, i.e. the parameters involved can be considered nearly independent of temperature.

We study the liquid-gas phase transition of stellar matter with the inclusion of the finite-size effect from surface and Coulomb energies. The equilibrium conditions for two coexisting phases are determined by minimizing the total free energy including the surface and Coulomb contributions, which are different from the Gibbs conditions used in the bulk calculations. The finite-size effect can significantly reduce the region of the liquid-gas mixed phase. The influence of the symmetry energy on the liquid-gas phase transition is investigated with the inclusion of finite-size effects. It is found that the slope of the symmetry energy plays an important role in determining the boundary and properties of the mixed phase., Comment: 29 pages, 11 figues

We report on new hidden states of matter created under femtosecond timescale non-equilibrium conditions in dichalcogenides and complex oxides, focusing on their origin, optical and electronic control, relaxation mechanisms and applications leading to ultrafast optomemristors.

The upper field of the Meissner regime, H up, and overheat field H′c1, above which vortices start penetrating into a Josephson contact, are calculated throughout the range of pinning parameter I. The stability of likely configurations is investigated. It is shown that H up = H′c1 at any I. The existence of a single vortex centered at the extreme cell in the contact is demonstrated to be a possibility. At I > 3.69, such a vortex may exist even in a zero magnetic field. At 1.48 < I < 3.69, this vortex can exist in an external field in the range from some H v to H up. At I < 1.48, the vortex cannot exist under any conditions. From the equality of H up and H′c1 at any I, the conclusion is drawn that penetration of vortices into any Josephson medium is conditioned by the need to satisfy flux quantization conditions. Here, not the forces of vortex pinning at defects in the medium but quantization requirements are of major importance, which are satisfied in specific quantum ways rather than by meeting equilibrium conditions for vortices, forces, etc.

The method of quasi-chemical reactions was used to construct the diagrams of point-defect equilibrium in GaN and GaN:Mg at 1400 K. According to these diagrams, it is impossible to obtain GaN with hole conductivity in equilibrium conditions. The nitrogen vacancies are shown to be the main acceptor-compensating centers in GaN.

A series of organic melting point temperature standards are available for which the liquefaction temperature has been determined by stepwise heating under near equilibrium conditions. The present work explores their use in the accurate calibration of DSC equipment. Two methods have been used, each of which has been shown to have advantages. In the first, a stepwise heating procedure has been adopted which is analogous to that used in calibrating the standards. The final step corresponds to the certified liquefaction temperature. In the alternative procedure the extrapolated onset temperature has been determined for zero heating rate. This work provides experimental confirmation that the extrapolated onset temperature at zero heating rate corresponds to the certified thermodynamic liquefaction temperature.

The kinetics and morphology of the grain boundary grooving of Zn bicrystals with 16° tilt GB by Sn(Zn) melt has been studied at 325°C in equilibrium conditions in vacuum. It is shown that grooving process is interface controlled at least on the first stage. Groove walls mobility is evaluated. Changing of GB grove shape from “faceted walls” corner for annealing time < 78 h to concave “Mullins type” groove for annealing time > 78 h at the same experimental temperature was observed for the first time.

The kinetics and morphology of the grain boundary grooving of Zn bicrystals with 16° tilt GB by Sn(Zn) melt has been studied at 325°C in equilibrium conditions in vacuum. It is shown that grooving process is interface controlled at least on the first stage. Groove walls mobility is evaluated. Changing of GB grove shape from “faceted walls” corner for annealing time < 78 h to concave “Mullins type” groove for annealing time > 78 h at the same experimental temperature was observed for the first time.

The present paper deals with dangling bonds creation in a-Si:H thin films under continuous light illumination with moderate intensity. Taking into account the equilibrium conditions of defect density given by the defect pool model, we propose that hydrogenated dangling bond is the dominant defect in good quality a-Si:H samples and the recombination occurs not only at weak SiSi bonds but also at SiHHSi configurations. The obtained dangling bonds creation kinetic according our model is in good agreement with experiments.

We consider lipid fluid vesicles described by the Helfrich Hamiltonian. We develop a geometrically covariant approach to derive the appropriate equilibrium conditions for these objects. This also allows us to derive general expressions for the stresses and torques acting within the vesicle. The appropriate generalization to models for inhomogeneous lipid vesicles is briefly described.

The equilibrium of a curved interface formed between two fluid phases, which are exposed to an external action is examined. The external action is shown to result in an energy jump across the interface thereby affecting the phase equilibrium. If stated in terms of an energy density of the phases, this action appears in both the Laplace and the Thomson equation as additional term.