Use Of Mixing Rules Research Articles

Machine learned interatomic potentials for modeling interfacial heat transport in Ge/GaAs

Molecular dynamics simulations provide a versatile framework to study interfacial heat transport, but their accuracy remains limited by the accuracy of available interatomic potentials. Past researchers relied on simple analytic potentials and the use of mixing rules to model interface systems, but with minimal justification for their use. Contemporary researchers have access to highly flexible machine learned interatomic potentials (MLIPs), yet these remain understudied within this problem domain. In either case, efforts are needed to rigorously assess and validate interatomic potentials prior to their use in MD simulations of interfacial heat transport. Here, we pursue these efforts while developing interatomic potentials for a model Ge/GaAs system. We first assess the quality of ab initio harmonic force constants (IFC2s) obtained from the interface structure that is used to generate fitting data for MLIPs. We show that these force constants can converge to near bulk-like values within 1 nm away from the interface while also exhibiting a complex relationship across the interface, which likely precludes any successful application of mixing rules. Subsequently, we develop two different MLIPs to model Ge/GaAs using the linear spectral neighborhood analysis potential (SNAP) functional form: one standard SNAP fit to total forces, and another hybrid SNAP fit to anharmonic force components and combined with a harmonic Taylor expansion potential. Each potential is evaluated with respect to bulk thermal properties, interface IFC2s, and stability considerations, providing a valuable comparative analysis that can guide future work.

QSAR study for predicting the ecotoxicity of NADES towards Aliivibrio fischeri. Exploring the use of mixing rules.

(Eco)toxicological information of natural deep eutectic solvents (NADES) is scarce, and thus, quantitative structure activity relationship (QSAR) models are an important tool for achieving the prediction of toxicity in this case. For that reason, in this manuscript, a new QSAR model for predicting the ecotoxicity of NADES towards the Aliivibrio fischeri biomodel, using mixing rules, is proposed. The main advantage of the method is that the individual components of the mixtures are molecularly modelled, and then, a mixing rule is used, which simplifies the process. For developing the model, a total of 11 descriptors for each component is used: the dissociation constant, partition coefficient, Van der Waals volume, Van der Waals surface area, topological polar surface area, solvent accessible surface area, minimum projection area, maximum projection area, minimum projection radius, maximum projection radius and molecular weight. The final obtained model includes the topological polar surface area and the dissociation constant, mechanistically interpreted as the ability of a NADES to transport through biological membranes and the severe negative effect of pH on the toxicity and biological response of Aliivibrio fischeri bacteria. The OECD Guidance Document on the Validation of (Quantitative) Structure-Activity Relationships is followed to develop the mathematical model.

Speed of sound prediction in 1 − n-alcohol + n-alkane mixtures using a translated SAFT-VR-Mie equation of state

For applications where accurate speed of sound estimates are needed, computation errors arising from direct use of equations of state, or from use of mixing rules based on pure component property data are too large. In this work we translate isentropic compressibility estimates for mixtures at specific compositions by adding the molar average error of the predicted isentropic compressibility for pure constituents to the isentropic compressibility of the mixture predicted using the SAFT-VR-Mie EOS. The translated isentropic compressibility values and mixture densities predicted by the EOS are then used to compute the speed of sound in mixtures. This procedure leads to better qualitative descriptions of the dependence of speed of sound in 1 − n-alkanol + n-alkane mixtures vis-à-vis current practice. The rms errors obtained are, on average, substantially lower than other methods that only make use of pure component data as inputs, and they are competitive with methods such as the Extended Real Association model (ERAS) which require composition specific mixture properties. The success of this computational approach may suggest that the SAFT-VR-Mie EOS can be used as a basis for speed of sound calculations for mixtures more generally. For n-alkanol + n-alkane mixtures, refinement of the repulsive terms in the SAFT-VR-Mie EOS is warranted because the ideal mixing rule out performs this computational approach in some cases.

Thermodynamic properties for the alternative refrigerants

Models commonly used to calculate the thermodynamic properties of refrigerants are summarized. For pure refrigerants, the virial, cubic, Martin-Hou, Benedict-Webb-Rubin, and Helmholtz energy equations of state and the extended corresponding states model are discussed. High-accuracy formulations for 16 refrigerants are recommended. These models may be extended to mixtures through the use of mixing rules applied either to the parameters of the equation of state or to some property of the mixture components. Mixtures of a specific composition may also be modeled as a pseudo-pure fluid. Five mixture models, employing four distinct approaches, have been compared by a group working under the auspices of the International Energy Agency. These comparisons show all five models to be very capable in representing mixture properties. No single model was best in all aspects, but based on its combination of excellent accuracy and great generality, we recommend the mixture Helmholtz energy model as the best available. Experimental data are essential to both fit the adjustable parameters in property models and to assess their accuracy. We present a survey of the data available for mixtures of the HFC refrigerants R32, R125, R143a, R134a, and R152a and for mixtures of the natural refrigerants propane, butane, isobutane, and carbon dioxide. More than 60 data references are identified. Further data needs include caloric data for additional mixtures, comprehensive pressure-density-temperature data for additional mixture compositions, and improved accuracy for vapor-liquid equilibria data.

Use of mixing rules in predicting refractive indexes and specific refractivities for some binary liquid mixtures. [Erratum to document cited in CA117(4):35662d

Use of mixing rules in predicting refractive indexes and specific refractivities for some binary liquid mixtures. [Erratum to document cited in CA117(4):35662d

Use of mixing rules in predicting refractive indexes and specific refractivities for some binary liquid mixtures

Refractive indices for the systems benzene-cyclohexane, acetone-cyclohexane have been measured at 25 o C over the composition range. These results, combined with the corresponding densities published earlier by us, were used to test the applicability of the Lorenz-Lorenz, Gladstone-Dale, Wiener, Heller, and Arago-Blot refractive index mixing rules. The Lorenz-Lorenz relation gave the best correlation for all systems investigated. The specific refractivities for mixtures studied were also calculated

Excess thermodynamic properties for { xCO 2 + (1 − x)C 2H 6} (I): experiment and theory

The excess molar enthalpies H m E of liquid mixtures of carbon dioxide and ethane have been determined calorimetrically at 217.0 and 230.0 K using a recently constructed microprocessor-controlled cryogenic calorimeter. The excess molar enthalpies are large, positive, and nearly independent of temperature in this range, while the dependence of H m E on mole fraction x is slightly asymmetric about x = 0.5. The value of H m E( x = 0.5) at p = 0 is (1450±30) J·mol −1 for both temperatures. The excess molar Gibbs energies G m E have been calculated using Barker's method at 223.15, 243.15, and 263.15 K from published phase-equilibrium data, and the excess molar volumes V m E at 241.5 K have been obtained from published liquid-mixture densities. The excess molar entropies S m E are large, positive, and slightly asymmetric about x = 0.5. The results for H m E, G m E and V m E are in good agreement with values calculated from perturbation theory using an anisotropic potential model. It is demonstrated that the use of mixing rules proposed by Kohler for determining unlike intermolecular potentials, which require no mixture-parameter fitting, yield more accurate values of the excess properties than the Lorentz-Berthelot rules.

Use of mixing rules in the analysis of data for binary liquid mixtures

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUse of mixing rules in the analysis of data for binary liquid mixturesTejraj M. AminabhaviCite this: J. Chem. Eng. Data 1984, 29, 1, 54–55Publication Date (Print):January 1, 1984Publication History Published online1 May 2002Published inissue 1 January 1984https://doi.org/10.1021/je00035a018RIGHTS & PERMISSIONSArticle Views451Altmetric-Citations46LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (212 KB) Get e-Alerts Get e-Alerts