scholarly journals Estimating a Stoichiometric Solid’s Gibbs Free Energy Model by Means of a Constrained Evolutionary Strategy

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 471
Author(s):  
Constantino Grau Turuelo ◽  
Sebastian Pinnau ◽  
Cornelia Breitkopf
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Evolutionary Strategy ◽  
Data Sets ◽  
Automatic Data ◽  
Physical Constraints ◽  
Stoichiometric Model ◽  
Covariance Matrix Adaptation ◽  
Dsc Measurements ◽  
Capacity Data

Modeling of thermodynamic properties, like heat capacities for stoichiometric solids, includes the treatment of different sources of data which may be inconsistent and diverse. In this work, an approach based on the covariance matrix adaptation evolution strategy (CMA-ES) is proposed and described as an alternative method for data treatment and fitting with the support of data source dependent weight factors and physical constraints. This is applied to a Gibb’s Free Energy stoichiometric model for different magnesium sulfate hydrates by means of the NASA9 polynomial. Its behavior is proved by: (i) The comparison of the model to other standard methods for different heat capacity data, yielding a more plausible curve at high temperature ranges; (ii) the comparison of the fitted heat capacity values of MgSO4·7H2O against DSC measurements, resulting in a mean relative error of a 0.7% and a normalized root mean square deviation of 1.1%; and (iii) comparing the Van’t Hoff and proposed Stoichiometric model vapor-solid equilibrium curves to different literature data for MgSO4·7H2O, MgSO4·6H2O, and MgSO4·1H2O, resulting in similar equilibrium values, especially for MgSO4·7H2O and MgSO4·6H2O. The results show good agreement with the employed data and confirm this method as a viable alternative for fitting complex physically constrained data sets, while being a potential approach for automatic data fitting of substance data.

Asymmetric Scaled Equation of State and Critical Behavior of Binary Mixtures

1988 ◽  
Vol 110 (4a) ◽  
pp. 986-991 ◽  
Author(s):  
M. A. Anisimov ◽  
S. B. Kiselev ◽  
I. G. Kostukova
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Equation Of State ◽  
Binary Mixtures ◽  
Critical Line ◽  
Universal Function ◽  
Wide Neighborhood ◽  
Critical Isochore ◽  
Experimental Heat ◽  
Capacity Data

An equation of state for binary mixtures, accounting for the asymmetry with respect to the critical isochore in the wide neighborhood of the liquid–gas critical line, has been obtained on the basis of the isomorphic scaled free energy of mixtures and the extended scaled equation of state for pure fluids. Universal behavior of critical binary mixtures is demonstrated. The universal function is used for the description of experimental heat capacity data for a number of binary mixtures.

Development of the room temperature protocol based on room temperature ionic liquids and surfactant ionic liquids for the synthesis of derivatives of 2-amino-thiazoles and thermo-physical analysis of the synthesized derivatives using TGA-DSC.

2020 ◽  
Vol 10 ◽  
Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Heat Capacity Data ◽  
General Strategy ◽  
Capacity Data ◽  
Derivatives Of

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.

Heat capacity of activation for the hydrolysis of methanesulfonyl chloride and benzenesulfonyl chloride in light and heavy water

1969 ◽  
Vol 47 (22) ◽  
pp. 4199-4206 ◽  
Author(s):  
R. E. Robertson ◽  
B. Rossall ◽  
S. E. Sugamori ◽  
L. Treindl
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Temperature Dependence ◽  
Heavy Water ◽  
Bond Formation ◽  
Sulfonyl Chlorides ◽  
Benzenesulfonyl Chloride ◽  
Methanesulfonyl Chloride ◽  
Hydrolysis Of ◽  
Parameter Temperature Dependence

Rates of solvolysis of methanesulfonyl chloride and benzenesulfonyl chloride have been determined in H2O and D2O. The free energy, enthalpy, entropy, and heat capacity of activation were calculated. The exceptional accuracy of the data permitted an estimation of dΔCp≠/dT from a four parameter temperature dependence of the kinetic rates.From these data we conclude that both sulfonyl chlorides hydrolyse by the same mechanism (Sn2) The change in R from CH3 to C6H5 in RSO2Cl did not alter ΔCp≠ but ΔS≠ (20°) was changed from −8.32 to −13.25 cal deg−1 mole−1, respectively. The significance of this difference is attributed to the probability of bond formation rather than to differences in solvent reorganization.

Acoustic Velocity Measurements and Interpretation for Challenging Fluid Systems

SPE Journal ◽  
2016 ◽  
Vol 22 (01) ◽  
pp. 103-119 ◽  
Author(s):  
Edward Lewis ◽  
Birol Dindoruk
Keyword(s):  
Heat Capacity ◽  
Isothermal Compressibility ◽  
Measured Data ◽  
Acoustic Velocity ◽  
Hydrocarbon Mixture ◽  
Data Sets ◽  
Velocity Measurements ◽  
Numerical Work ◽  
Reliable Determination ◽  
Quality Control Tool

Summary In terms of experimentation, acoustic velocity can be measured with a high degree of accuracy. Several thermodynamic properties related to acoustic velocity such as density, isothermal compressibility, and heat capacity can be extracted from measured data. In this study, technical improvements are implemented in an effort to develop a technique for fast and reliable determination of fluid properties on the basis of acoustic velocity measurements over an expanded range of pressures. The potential use of this device as a quality-control tool in typical pressure/volume/temperature (PVT) measurements is demonstrated. Baseline measurements matched to published literature verify the suitability of the device. Results of tests on three recombined oil samples containing dissolved gas, with prescribed gas/oil ratios (GORs), and one bitumen sample are presented. A sharp change in the acoustic velocity trend near the gas/liquid-saturation point is evidence of gas evolution during depressurization. Strong attenuation complicates measurement of acoustic velocity on the heavy fluids used in this study. Blending bitumen with a midrange-molecular-weight hydrocarbon mixture enables estimation of the undiluted-fluid acoustic velocity by extrapolation. By use of the measured acoustic velocity data available, a methodology is developed to estimate and quality check measured isothermal compressibility (κT) values. This is especially important for low-compressibility systems. Heat-capacity data for simple alkanes (CH4 to n-C10) and toluene helps to define a reasonable range of heat-capacity ratio (γ) expected for typical reservoir fluids. For the typical values of acoustic velocity encountered in the pressure and temperature range of interest, the isothermal compressibility can be calculated and/or quality checked by use of estimated values of γ. In addition, by use of various data sets and by performing graphical error analysis, we have shown the reasons that the methodology works. Available data for n-decane and n-hexadecane along with measured data for a live oil and numerical work on calibrated data sets in this study are used to develop the methodology.

scholarly journals Теплоемкость и магнитокалорический эффект соединений LaFe-=SUB=-11.2-x-=/SUB=-Mn-=SUB=-x-=/SUB=-Co-=SUB=-0.7-=/SUB=-Si-=SUB=-1.1-=/SUB=- (x=0, 0.1, 0.2, 0.3)

2020 ◽  
Vol 62 (5) ◽  
pp. 752
Author(s):  
Н.З. Абдулкадирова ◽  
А.М. Алиев ◽  
А.Г. Гамзатов ◽  
P. Gebara
Keyword(s):  
Heat Capacity ◽  
Magnetic Fields ◽  
Curie Temperature ◽  
Specific Heat ◽  
Magnetocaloric Effect ◽  
Intermetallic Compounds ◽  
Indirect Method ◽  
Direct Method ◽  
Capacity Data ◽  
Value Changes

The specific heat and magnetocaloric effect of the LaFe11.2-хMnxCo0.7Si1.1 intermetallic compounds (x = 0.1, 0.2, 0.3) were measured in the temperature range 80–300 K and in magnetic fields up to 8 T. The magnetocaloric effect (MCE) was estimated using two methods: direct method in cyclic magnetic fields, as well as an indirect method from heat capacity data. It was shown that an increase in the concentration of Mn atoms leads to a shift in the Curie temperature of the TC toward lower temperatures, while the FM value changes slightly.

scholarly journals Enhancing Water Sampling in Free Energy Calculations with Grand Canonical Monte Carlo

2020 ◽  
Author(s):  
Gregory Ross ◽  
Ellery Russell ◽  
Yuqing Deng ◽  
Chao Lu ◽  
Edward Harder ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Free Energy ◽  
Drug Discovery ◽  
Free Energy Calculations ◽  
Data Sets ◽  
Grand Canonical Monte Carlo ◽  
Enhanced Sampling ◽  
Computational Performance ◽  
Energy Perturbation ◽  
Grand Canonical

<div>The prediction of protein-ligand binding affinities using free energy perturbation (FEP) is becoming increasingly routine in structure-based drug discovery. Most FEP packages use molecular dynamics (MD) to sample the configurations of proteins and ligands, as MD is well-suited to capturing coupled motion. However, MD can be prohibitively inefficient at sampling water molecules that are buried within binding sites, which has severely limited the domain of applicability of FEP and its prospective usage in drug discovery. In this paper, we present an advancement of FEP that augments MD with grand canonical Monte Carlo (GCMC), an enhanced sampling method, to overcome the problem of sampling water. We accomplished this without degrading computational performance. On both old and newly assembled data sets of proteinligand complexes, we show that the use of GCMC in FEP is essential for accurate and robust predictions for ligand perturbations that disrupt buried water. <br></div>

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