Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 2. Phase Boundaries

2000 ◽  
Vol 45 (6) ◽  
pp. 1139-1149 ◽  
Author(s):  
Vladimir M. Valyashko ◽  
Ilmutdin M. Abdulagatov ◽  
Johanna M. H. Levelt Sengers
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Sodium Carbonate ◽  
Sodium Sulfate ◽  
Solid Phase ◽  
Phase Boundaries ◽  
Vapor Liquid Solid ◽  
Aqueous Sodium ◽  
End Point ◽  
Heat Capacity Measurements

Liquid−Liquid−Vapor, Liquid−Liquid, and Liquid−Vapor Phase Transitions in Aqueousn-Hexane Mixtures from Isochoric Heat Capacity Measurements

2001 ◽  
Vol 46 (6) ◽  
pp. 1556-1567 ◽  
Author(s):  
Ibragimkhan K. Kamilov ◽  
Gennadii V. Stepanov ◽  
Ilmutdin M. Abdulagatov ◽  
Anvar R. Rasulov ◽  
Elena I. Milikhina
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Vapor Phase ◽  
Isochoric Heat Capacity ◽  
Heat Capacity Measurements ◽  
Liquid Vapor ◽  
Vapor Liquid

Thermodynamic investigations of zeolites NaX and NaY

2006 ◽  
Vol 84 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Liyan Qiu ◽  
Patricia A Laws ◽  
Bi-Zeng Zhan ◽  
Mary Anne White
Keyword(s):  
Particle Size ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Size Effect ◽  
Thermodynamic Stability ◽  
Aluminum Content ◽  
Particle Size Effect ◽  
Al Content ◽  
Heat Capacity Measurements ◽  
Zeolitic Materials

Understanding of the thermodynamic stability of zeolites is important in the prediction of thermodynamic equilibrium. Therefore, we have undertaken an investigation of the thermodynamic stability of the zeolites NaX and NaY through heat capacity measurements from ca. 30 to 300 K. No phase transitions were observed, and zeolite NaX does not show a significant particle size effect when the particle size is reduced to ca. 30 nm. The results show that the specific heat capacity increases with the Al content in the zeolite. Both NaX and NaY are found to be thermodynamically stable with respect to their elements because of enthalpic stabilization and with slight entropic destabilization. These data are used along with literature data for many other zeolitic materials to show that the thermodynamic stability of zeolites is enhanced with increasing aluminum content. Key words: zeolite, heat capacity, thermodynamic stability, nano effects.

The thermodynamics of orientational disorder in a molecular solid: (CH3)3CCHO

1988 ◽  
Vol 66 (4) ◽  
pp. 729-733 ◽  
Author(s):  
Mary Anne White ◽  
Allyson Perrott
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Solid State ◽  
Magnetic Resonance ◽  
Thermodynamic Parameters ◽  
Solid Phase ◽  
Orientational Disorder ◽  
Molecular Solid ◽  
Nuclear Magnetic

The heat capacity of tert-butylaldehyde, (CH3)3CCHO, has been measured as a function of temperature from 29 to 298 K, to investigate solid-state polymorphism. There are two solid–solid phase transitions in this material, Ttr = 158.5 and 183.9 K, ΔStr = 0.402 R and 3.153 R respectively. The thermodynamic parameters for the transitions are consistent with mechanisms proposed on the basis of recent nuclear magnetic resonance investigations of this material.

Enhanced Specific Heat Capacity of Nanomaterials Synthesized by Dispersing Silica Nanoparticles in Eutectic Mixtures

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Donghyun Shin ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Silica Nanoparticles ◽  
Specific Heat Capacity ◽  
Solid Phase ◽  
Thermal Power ◽  
Lithium Carbonate ◽  
Molar Ratio ◽  
Heat Capacity Measurements ◽  
The Cost

Anomalous enhancements in the specific heat capacity values of nanomaterials were measured in this study. Silica nanoparticles (∼2–20 nm) were dispersed into eutectic of lithium carbonate and potassium carbonate (62:38 by molar ratio) at 1.5% mass concentration. The specific heat capacity measurements were performed using a differential scanning calorimeter (DSC). The specific heat capacity of the silica nanocomposite (solid phase) was enhanced by 38–54% and the specific heat of the silica nanofluid (liquid phase) was enhanced by 118–124% over that of the pure eutectic. Electron microscopy of the samples shows that the nanoparticles induce phase change (forms a higher density “compressed phase”) within the solvent material. Hence, a new model is proposed to account for the contribution of the compressed phase to the total specific heat capacity of the nanomaterials. The proposed model is found to be in good agreement with the experimental data. These results have wide ranging implications, such as for the development of efficient thermal storage systems that can enable significant reduction in the cost of solar thermal power.

Phase transitions in : I, heat capacity measurements

1982 ◽  
Vol 110 (2-3) ◽  
pp. 317-323 ◽  
Author(s):  
Keiji Naito ◽  
Hideaki Inaba ◽  
Seiichi Takahashi
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Heat Capacity Measurements
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