Research Article
Electronic and Mechanical Properties of Chemical Bonds (A-O & B-O) in Cubic Phase A+2B+4O3 Perovskite Oxides
Niharika Yadav,
Dhirendra Singh Yadav*,
Preeti Varshney,
Rajesh Chandra Gupta
Issue:
Volume 11, Issue 4, July 2023
Pages:
80-88
Received:
25 September 2023
Accepted:
16 October 2023
Published:
9 November 2023
Abstract: In the present manuscript, electronic and mechanical properties of a series of ABO3 (A→ alkaline earth metals, B→ transition metal) perovskites are presented. Using the plasma oscillation theory of solids, empirical relations are proposed for computation of the homopolar/ covalent gap (Eh) and heteropolar/ ionic gap (Ec) of the chemical bonds A-O and B-O in the cubic phase of ABO3 perovskites. To examine the validity of our calculated results, the average energy gap (Eg), Phillips ionicity (fi) and covalence (fc) of the chemical bonds of these perovskites are investigated. The dielectric constant (ε∞) and refractive index (n) are computed and the results obtained are analyzed in comparison to results obtained by different researchers and these are found in fairly good agreement. Electronic polarizability (αtotal) was calculated through a well-known phenomenological Clausius-Mossotti relation and the values were found in accord with the results obtained from the Chemla’s relation. Further, a simple Neumann scaling approach has been employed to estimate the bulk modulus of these materials using the Phillips ionicity model. Present estimations are found in excellent agreement with the available experimental reports as compared to other such previous theoretical reports. This report supports the composition of new perovskites and hereto perceives their other properties for optoelectronics, photonics, mechanical and thermoelectric devices.
Abstract: In the present manuscript, electronic and mechanical properties of a series of ABO3 (A→ alkaline earth metals, B→ transition metal) perovskites are presented. Using the plasma oscillation theory of solids, empirical relations are proposed for computation of the homopolar/ covalent gap (Eh) and heteropolar/ ionic gap (Ec) of the chemical bonds A-O a...
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Research Article
Heat Transfer Behavior of a PTC Receiver Tube Using Transversal Focal Inserts and CFD
Haddouche Mohammed Reda*,
Haddouche Abdelhadi,
Benazza Abdelylah
Issue:
Volume 11, Issue 4, July 2023
Pages:
89-98
Received:
5 October 2023
Accepted:
3 November 2023
Published:
17 November 2023
Abstract: In this paper the thermohydraulic performance of an improved Parabolic Trough Collector tube is investigated. Since the absorber tube of the Parabolic Trough Collector is subjected to non-uniform heat flux, and the focal part of the absorber is subjected to a concentrated solar flux, a temperature gradient on the tube circumferential surface is produced. In order to enhance the heat transfer between the Heat Transfer Fluid and the inner surface of the absorber tube and decrease the temperature gradient of the tube’s outer surface and also the temperature of the Heat Transfer Fluid inside the absorber tube, transversal focal inserts are placed on the receiver tube's bottom part as a passive method to increase the mixing of the fluid and decrease the temperature gradient. The geometrical parameter of the inserts as the insert’s height is analyzed and investigated using Finite Volume Method coupling Monte Carlo Ray Tracing method for Reynolds number range from 2.36x104 to 11.83x104. The Therminol®VP1is used as Heat Transfer Fluid in this study. The numerical results show that the enhanced tube by using this kind of inserts increases the thermal performance of the Parabolic Trough Collector system, and also, introducing the inserts into the receiver tube reduces the heat loss to the ambient, decreases the temperature differential across the absorber tube's circumferential region, and increases the receiver's lifespan.
Abstract: In this paper the thermohydraulic performance of an improved Parabolic Trough Collector tube is investigated. Since the absorber tube of the Parabolic Trough Collector is subjected to non-uniform heat flux, and the focal part of the absorber is subjected to a concentrated solar flux, a temperature gradient on the tube circumferential surface is pro...
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