scholarly journals Study of Elastic Properties of Ionic Solids at High Temperature and Volume Expansion Ratio

Author(s):  
Sanjay Singh

In our study we develop a new expression for temperature dependence of thermal pressure for MgO and CaO crystal. A generally elastic property of solid depends on the strength of inter atomic forces of solid. So far our work has been resolute on thermal pressure is dependent of temperature and diverges it’s linearly in high temperature volume expansion ratio through the effect of temperature. This present method has been developed on the temperature dependence of thermal pressure for MgO and CaO crystal at atmospheric pressure and volume expansion ratio at high temperature. A neighboring data of Gruneisen parameter is found to be in close convention with theoretical and investigational confirmations the standing of present study.

Author(s):  
S Singh ◽  
P. K. Singh ◽  
S. K. Pathak

In the present study, we derived new relationship and expression for temperature dependence of thermal pressure for NaCl crystal. A mostly elastic property of solid depends on the strength of inter atomic forces of solids. The present work approach has been developed on the temperature dependence of thermal pressure for NaCl crystal at atmospheric pressure and volume expansion ratio at high temperature. So far our work has been concerted on thermal pressure is dependent of temperature and diverges it’s linearly in high temperature volume expansion ratio through effect of temperature. A close data and Gruneisen parameter is found to be in close agreement with investigational and theoretical shows the standing of present study.


2009 ◽  
Vol 23 (11) ◽  
pp. 2503-2509 ◽  
Author(s):  
S. K. SHARMA

The present paper proposes a computing model for temperature dependence of volume thermal expansivity, volume expansion ratio and second order temperature derivative of volume based on the assumption that the product αKT remains constant at high temperatures and zero pressure. We have taken NaCl and KCl to testify the validity of the present model. A fairly close agreement between the calculated results and experimental data strongly supports the present model.


2014 ◽  
Vol 1019 ◽  
pp. 379-384
Author(s):  
M.P. Mashamaite ◽  
Hasani Rich Chauke ◽  
Rosinah Mahlangu ◽  
P.E. Ngoepe

Shape memory alloys (SMAs) are a fascinating group of metals that have two remarkable properties, the shape memory effect and superelasticity. The TiPt structure with the B2 phase has been reported to undergo a reversible displacive transformation to B19 martensite at about 1200K. However, this system could serve in principle as the basis of high-temperature shape memory alloys. Molecular dynamics study of martensitic transformation in platinum titanium alloys was performed to investigate the effect of temperature dependence on B2 and B19 structures at 50 at.%Pt. The NPT ensemble was used to determine the properties of these systems and we found good comparisons with recent experimental work. The temperature dependence of TiPt shows potential martensitic change when B19 is heated to extreme high temperatures of 273K up to 1573K.


2001 ◽  
Vol 68 (4) ◽  
pp. 625-637 ◽  
Author(s):  
LINDA R. LUDIKHUYZE ◽  
WENDIE L. CLAEYS ◽  
MARC E. HENDRICKX

At atmospheric pressure, inactivation of lactoperoxidase (LPO) in milk and whey was studied in a temperature range of 69–73 °C and followed first order kinetics. Temperature dependence of the first order inactivation rate constants could be accurately described by the Arrhenius equation, with an activation energy of 635·3±70·7 kJ/mol for raw bovine milk and 736·9±40·9 kJ/mol for diluted whey, indicating a very high temperature sensitivity. On the other hand, LPO is very pressure resistant and not or only slightly affected by treatment at pressure up to 700 MPa combined with temperatures between 20 and 65 °C. Both for thermal and pressure treatment, stability of LPO was higher in milk than in diluted whey. Besides, a very pronounced antagonistic effect between high temperature and pressure was observed, i.e. at 73 °C, a temperature where thermal inactivation at atmospheric pressure occurs rapidly, application of pressure up to 700 MPa exerted a protective effect. At atmospheric pressure, LPO in diluted whey was optimally active at a temperature of about 50 °C. At all temperatures studied (20–60 °C), LPO remained active during pressure treatment up to 300 MPa, although the activity was significantly reduced at pressures higher than 100 MPa. The optimal temperature was found to shift to lower values (30–40 °C) with increasing pressure.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1655 ◽  
Author(s):  
Xiaohui Zeng ◽  
Huasheng Zhu ◽  
Xuli Lan ◽  
Haichuan Liu ◽  
H.A Umar ◽  
...  

In order to solve the problems of the sudden loss of fluidity and low expansion rate of CAM I (cement asphalt mortar type I) in a construction site with high environmental temperature, this paper studies the effect of temperature on the fluidity, expansion ratio and pH value of CAM I. The mechanism of action was analyzed by IR (infrared spectrometry), SEM (scanning electron microscopy) and other test methods. The results showed that a high temperature accelerates aluminate formation in cement paste. Aluminate adsorbs emulsifiers leading to demulsification of emulsified asphalt, and wrapped on the surface of cement particles, this causes CAM I to lose its fluidity rapidly. The aluminum powder gasification reaction is inhibited, resulting in an abnormal change in the expansion ratio. Based on findings, the application of an appropriate amount of superplasticizers can effectively improve the workability and expansion characteristics of CAM I at a high temperature.


1990 ◽  
Vol 5 (3) ◽  
pp. 152-154 ◽  
Author(s):  
L. Boon ◽  
H. de Jonge Baas ◽  
R. Metselaar

AbstractThe temperature dependence of the cell parameters is given for Bi2Mo3O12, Bi2Mo2O9, γ-Bi2MoO6 and γ'-Bi2MoO6, and the volume expansion coefficient is derived. A description is given of a high-temperature diffractometer (HTD) for temperatures up to about 1600°C in controlled atmospheres.


Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.


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