Enthalpy Relaxation Phenomenon in a Heavy Ice Crystal

Abstract The heat capacities of quenched and annealed heavy ice Ih were measured in the temperature range 14 to 300 K by an adiabatic calorimeter. A relaxational thermal anomaly was found at around 115 K and this phenomenon was ascribed to the onset of deuteron ordering in the crystal. The average activation enthalpy of the relaxational process was determined to be (26±5) kJ mol-1. Residual entropies of the crystal were recalculated on the basis of the present heat-capacity data combined with the revised values for enthalpy of vaporization, saturated vapour pressure, and spectroscopic entropy. They are (3.47±0.41 J K-1 mol-1 for the quenched crystal and (3.44±0.41) J K-1 mol-1 for a crystal annealed at 102-106 K for 264 h. The characteristics and the origin of the anomaly are discussed in comparison with that of ordinary ice. This paper has been accepted for publication in full in a forthcoming issue of the Journal of Glaciology.

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Enthalpy Relaxation Phenomenon in a Heavy Ice Crystal

Journal of Glaciology ◽

10.3189/s0022143000033931 ◽

1978 ◽

Vol 21 (85) ◽

pp. 707-707

Author(s):

Osamu Haida ◽

Hiroshi Suga ◽

Syūzō Seki

Keyword(s):

Heat Capacity ◽

Activation Enthalpy ◽

Thermal Anomaly ◽

Adiabatic Calorimeter ◽

Enthalpy Of Vaporization ◽

Ice Crystal ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

Relaxational Process ◽

Capacity Data

AbstractThe heat capacities of quenched and annealed heavy ice Ih were measured in the temperature range 14 to 300 K by an adiabatic calorimeter. A relaxational thermal anomaly was found at around 115 K and this phenomenon was ascribed to the onset of deuteron ordering in the crystal. The average activation enthalpy of the relaxational process was determined to be (26±5) kJ mol-1. Residual entropies of the crystal were recalculated on the basis of the present heat-capacity data combined with the revised values for enthalpy of vaporization, saturated vapour pressure, and spectroscopic entropy. They are (3.47±0.41 J K-1 mol-1 for the quenched crystal and (3.44±0.41) J K-1 mol-1 for a crystal annealed at 102-106 K for 264 h. The characteristics and the origin of the anomaly are discussed in comparison with that of ordinary ice.This paper has been accepted for publication in full in a forthcoming issue of the Journal of Glaciology.

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Enthalpy Relaxation Phenomenon of Heavy Ice

Journal of Glaciology ◽

10.3189/s0022143000014131 ◽

1979 ◽

Vol 22 (86) ◽

pp. 155-164

Author(s):

Osamu Haida ◽

Hiroshi Suga ◽

Syūzō Seki

Keyword(s):

Heat Capacity ◽

Vapour Pressure ◽

Activation Enthalpy ◽

Thermal Anomaly ◽

Adiabatic Calorimeter ◽

Heat Capacity Data ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

Relaxational Process ◽

Capacity Data

AbstractThe heat capacities of quenched and annealed heavy ice Ih were measured in the temperature range 14 to 300 K by an adiabatic calorimeter. A relaxational thermal anomaly was found at around 115K and this phenomenon was ascribed to the onset of deuteron ordering in the crystal. The average activation enthalpy of the relaxational process was determined to be (26±5) kJ mol–1. Residual entropies of the crystal were recalculated on the basis of the present heat-capacity data combined with the revised values for enthalpy of vapourization, saturated vapour pressure, and spectroscopic entropy. They are (3.47±0.41) J K–1 mol–1 for the quenched crystal and (3.44±0.41) J K–1 mol–1 for the crystal annealed at 102–106 K for 264 h. The characteristics and the origin of the anomaly are discussed in comparison with that of ordinary ice.

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Enthalpy Relaxation Phenomenon of Heavy Ice

Journal of Glaciology ◽

10.1017/s0022143000014131 ◽

1979 ◽

Vol 22 (86) ◽

pp. 155-164 ◽

Cited By ~ 26

Author(s):

Osamu Haida ◽

Hiroshi Suga ◽

Syūzō Seki

Keyword(s):

Heat Capacity ◽

Vapour Pressure ◽

Activation Enthalpy ◽

Thermal Anomaly ◽

Adiabatic Calorimeter ◽

Heat Capacity Data ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

Relaxational Process ◽

Capacity Data

AbstractThe heat capacities of quenched and annealed heavy ice Ih were measured in the temperature range 14 to 300 K by an adiabatic calorimeter. A relaxational thermal anomaly was found at around 115K and this phenomenon was ascribed to the onset of deuteron ordering in the crystal. The average activation enthalpy of the relaxational process was determined to be (26±5) kJ mol–1. Residual entropies of the crystal were recalculated on the basis of the present heat-capacity data combined with the revised values for enthalpy of vapourization, saturated vapour pressure, and spectroscopic entropy. They are (3.47±0.41) J K–1mol–1for the quenched crystal and (3.44±0.41) J K–1mol–1for the crystal annealed at 102–106 K for 264 h. The characteristics and the origin of the anomaly are discussed in comparison with that of ordinary ice.

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Relation of the temperature derivative of heat of vaporization to the difference of heat capacities along the saturated vapour pressure curve

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19812446 ◽

1981 ◽

Vol 46 (10) ◽

pp. 2446-2454

Author(s):

Václav Svoboda ◽

Zdeněk Wagner ◽

Petr Voňka ◽

Jiří Pick

Keyword(s):

Heat Capacity ◽

Vapour Pressure ◽

Pressure Curve ◽

Temperature Derivative ◽

Heat Of Vaporization ◽

Saturated Vapour Pressure ◽

Saturated Vapour ◽

Vapour Pressure Curve ◽

Pure Substances ◽

The Difference

A method of calculating the heat capacity difference of liquid and its vapour along saturated vapour pressure curve is discussed. The qualitative course of this difference in dependence on temperature obtained from the data on the temperature dependence of heat of vaporization of pure substances is judged.

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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.

Current Physical Chemistry ◽

10.2174/1877946810999200519102040 ◽

2020 ◽

Vol 10 ◽

Cited By ~ 1

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.

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

Materials ◽

10.3390/ma14020471 ◽

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.

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