Thermal Properties of CuGa2 Phase in Inert Atmosphere

2012 ◽  
Vol 326-328 ◽  
pp. 227-232 ◽  
Author(s):  
T.V. Kulikova ◽  
V.A. Bykov ◽  
K. Y. Shunyaev ◽  
A.B. Shubin
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Thermal Decomposition ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Experimental Studies ◽  
Inert Atmosphere ◽  
Heat Conductivity Coefficient ◽  
Incongruent Melting ◽  
Modeling Methods

Thermal decomposition of copper digallide was studied using experimental (thermal analysis) and theoretical (thermodynamic modeling) methods. The temperatures of CuGa2incongruent melting are in satisfactory agreement between experimental and calculated values. Small differences with the phase diagram can be explained by minor non-stoichiometry of the alloy samples. The experimental studies of thermal diffusivity and thermal expansion of CuGa2were performed in the temperature range 298-500 K. The heat conductivity coefficient was further calculated using literary data concerning the density and heat capacity of the copper digallide.

Experimental Studies and Thermodynamic Modeling of the Interaction of O2 with SiC

2002 ◽  
Vol 742 ◽  
Author(s):  
Y. Song ◽  
F. W. Smith
Keyword(s):  
Phase Diagram ◽  
Thermal Decomposition ◽  
High Temperatures ◽  
Thermodynamic Modeling ◽  
Surface Segregation ◽  
Experimental Studies ◽  
Temperature Phase ◽  
Temperature Phase Diagram

ABSTRACTWe report on experimental studies and thermodynamic modeling of the reaction of O2 with the 4H- and 6H-SiC surfaces at high temperatures. This reaction leads to the growth of passivating SiO2 layers at high O2 pressures, etching of the surfaces at lower pressures, and enhancements of the surface segregation of carbon at still lower pressures. A pressure-temperature phase diagram for the oxidation of SiC is presented. Evidence for the thermal decomposition of the SiO2 layer on SiC is also presented.

scholarly journals Equations of State of Ca-Silicates and Phase Diagram of the CaSiO3 System under Upper Mantle Conditions

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 322
Author(s):  
Tatiana S. Sokolova ◽  
Peter I. Dorogokupets
Keyword(s):  
Phase Diagram ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Thermodynamic Model ◽  
Upper Mantle ◽  
Equations Of State ◽  
Calculated Density ◽  
Wide Range ◽  
Prem Model ◽  
Casio3 Perovskite

The equations of state of different phases in the CaSiO3 system (wollastonite, pseudowollastonite, breyite (walstromite), larnite (Ca2SiO4), titanite-structured CaSi2O5 and CaSiO3-perovskite) are constructed using a thermodynamic model based on the Helmholtz free energy. We used known experimental measurements of heat capacity, enthalpy, and thermal expansion at zero pressure and high temperatures, and volume measurements at different pressures and temperatures for calculation of parameters of equations of state of studied Ca-silicates. The used thermodynamic model has allowed us to calculate a full set of thermodynamic properties (entropy, heat capacity, bulk moduli, thermal expansion, Gibbs energy, etc.) of Ca-silicates in a wide range of pressures and temperatures. The phase diagram of the CaSiO3 system is constructed at pressures up to 20 GPa and temperatures up to 2000 K and clarifies the phase boundaries of Ca-silicates under upper mantle conditions. The calculated wollastonite–breyite equilibrium line corresponds to equation P(GPa) = −4.7 × T(K) + 3.14. The calculated density and adiabatic bulk modulus of CaSiO3-perovskite is compared with the PREM model. The calcium content in the perovskite composition will increase the density of mineral and it good agree with the density according to the PREM model at the lower mantle region.

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.

scholarly journals An Experimental Study of the Decomposition and Carbonation of Magnesium Carbonate for Medium Temperature Thermochemical Energy Storage

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1316
Author(s):  
Daniel Mahon ◽  
Gianfranco Claudio ◽  
Philip Eames
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Energy Storage ◽  
Magnesium Carbonate ◽  
Experimental Results ◽  
Future Research ◽  
Medium Temperature ◽  
Different Temperatures ◽  
Decomposition Enthalpy ◽  
Co2 Atmosphere

To improve the energy efficiency of an industrial process thermochemical energy storage (TCES) can be used to store excess or typically wasted thermal energy for utilisation later. Magnesium carbonate (MgCO3) has a turning temperature of 396 °C, a theoretical potential to store 1387 J/g and is low cost (~GBP 400/1000 kg). Research studies that assess MgCO3 for use as a medium temperature TCES material are lacking, and, given its theoretical potential, research to address this is required. Decomposition (charging) tests and carbonation (discharging) tests at a range of different temperatures and pressures, with selected different gases used during the decomposition tests, were conducted to gain a better understanding of the real potential of MgCO3 for medium temperature TCES. The thermal decomposition (charging) of MgCO3 has been investigated using thermal analysis techniques including simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), TGA with attached residual gas analyser (RGA) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) (up to 650 °C). TGA, DSC and RGA data have been used to quantify the thermal decomposition enthalpy from each MgCO3.xH2O thermal decomposition step and separate the enthalpy from CO2 decomposition and H2O decomposition. Thermal analysis experiments were conducted at different temperatures and pressures (up to 40 bar) in a CO2 atmosphere to investigate the carbonation (discharging) and reversibility of the decarbonation–carbonation reactions for MgCO3. Experimental results have shown that MgCO3.xH2O has a three-step thermal decomposition, with a total decomposition enthalpy of ~1050 J/g under a nitrogen atmosphere. After normalisation the decomposition enthalpy due to CO2 loss equates to 1030–1054 J/g. A CO2 atmosphere is shown to change the thermal decomposition (charging) of MgCO3.xH2O, requiring a higher final temperature of ~630 °C to complete the decarbonation. The charging input power of MgCO3.xH2O was shown to vary from 4 to 8136 W/kg with different isothermal temperatures. The carbonation (discharging) of MgO was found to be problematic at pressures up to 40 bar in a pure CO2 atmosphere. The experimental results presented show MgCO3 has some characteristics that make it a candidate for thermochemical energy storage (high energy storage potential) and other characteristics that are problematic for its use (slow discharge) under the experimental test conditions. This study provides a comprehensive foundation for future research assessing the feasibility of using MgCO3 as a medium temperature TCES material. Future research to determine conditions that improve the carbonation (discharging) process of MgO is required.

Theoretical and experimental studies on the thermal decomposition of 1-butyl-3-methylimidazolium dibutyl phosphate

2020 ◽  
Vol 65 ◽  
pp. 104162
Author(s):  
Shunchao Li ◽  
Huichun Jiang ◽  
Min Hua ◽  
Xuhai Pan ◽  
Hangchen Li ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Experimental Studies

Comparison of thermal expansion and heat capacity properties of various borosilicate glass-bonded strontium chloroapatite composites loaded with simulated pyrochemical waste

2014 ◽  
Vol 119 (3) ◽  
pp. 1825-1831 ◽  
Author(s):  
Binoy Kumar Maji ◽  
Hrudananda Jena ◽  
R. Venkata Krishnan ◽  
R. Asuvathraman ◽  
K. Ananthasivan ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Thermal Expansion ◽  
Borosilicate Glass

Heat capacity and thermal expansion of the itinerant helimagnet MnSi

2008 ◽  
Vol 20 (23) ◽  
pp. 235222 ◽  
Author(s):  
S M Stishov ◽  
A E Petrova ◽  
S Khasanov ◽  
G Kh Panova ◽  
A A Shikov ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Thermal Expansion

Development of Distortion Modeling Methods for Large Welded Structures

2010 ◽  
Author(s):  
Y. P. Yang ◽  
H. Castner ◽  
N. Kapustka
Keyword(s):  
Thermal Analysis ◽  
Plastic Strain ◽  
Computation Time ◽  
Thermomechanical Analysis ◽  
Global Model ◽  
Temperature History ◽  
Plastic Strains ◽  
Local Models ◽  
Welded Structures ◽  
Modeling Methods

Two distortion modeling methods, mapping plastic strain and lump-pass modeling, were developed and validated for predicting distortion on large welded structures to reduce the computation time. The mapping plastic-strain method requires two kinds of models, local models and a global model. The local models are analyzed to predict plastic strains and the global model is analyzed by mapping the plastic strains to predict distortions. The lump-pass modeling method includes two kinds of analyses: a thermal analysis and a thermomechanical analysis. The thermal analysis is conducted to predict temperature history. The thermomechanical analysis is performed to predict distortion by inputting the predicted temperature history.

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