thermodynamical properties
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2021 ◽  
Vol 51 (4) ◽  
pp. 67-89
Author(s):  
Anna Turlej ◽  
Marta Skolniak ◽  
Jacek Nowosielski

Abstract Ionic liquids as anticorrosion agents have a wide spectrum of unique properties, which make them less harmful than the majority of typical organic corrosion inhibitors in antifreeze. The synthesis of ionic liquids enables them to be provided with the desired physicochemical and thermodynamical properties by the appropriate selection of cations, anions, and alkyl substituents on the cations. The aim of this paper is the synthesis of the gemini ionic salt (ionic liquid) made up of two imidazole rings with a linear alkyl substituent with 10 carbon atoms, bonded by a 1,4-dimethylphenyl moiety. Such compounds are studied in view of steel protection against oxidizing and corrosive effects. The compound was obtained in a satisfactory yield.


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Di Wu ◽  
Shuang-Qing Wu

Abstract By taking the ultra-spinning limit as a simple solution-generating trick, a novel class of ultra-spinning charged black hole solutions has been constructed from Chow’s rotating charged black hole with two equal-charge parameters in six-dimensional $$ \mathcal{N} $$ N = 4 gauged supergravity theory. We investigate their thermodynamical properties and then demonstrate that all thermodynamical quantities completely obey both the differential first law and the Bekenstein-Smarr mass formula. For the six-dimensional ultra-spinning Chow’s black hole with only one rotation parameter, we show that it does not always obey the reverse isoperimetric inequality, thus it can be either sub-entropic or super-entropic, depending upon the ranges of the mass parameter and especially the charge parameter. This property is obviously different from that of the six-dimensional singly-rotating Kerr-AdS super-entropic black hole, which always strictly violates the RII. For the six-dimensional doubly-rotating Chow’s black hole but ultra-spinning only along one spatial axis, we point out that it may also obey or violate the RII, and can be either super-entropic or sub-entropic in general.


2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Shoichiro Miyashita

Abstract Gravitational thermodynamics and gravitoscalar thermodynamics with S2 × ℝ boundary geometry are investigated through the partition function, assuming that all Euclidean saddle point geometries contribute to the path integral and dominant ones are in the B3 × S1 or S2 × Disc topology sector. In the first part, I concentrate on the purely gravitational case with or without a cosmological constant and show there exists a new type of saddle point geometry, which I call the “bag of gold(BG) instanton,” only for the Λ > 0 case. Because of this existence, thermodynamical stability of the system and the entropy bound are absent for Λ > 0, these being universal properties for Λ ≤ 0. In the second part, I investigate the thermodynamical properties of a gravity-scalar system with a φ2 potential. I show that when Λ ≤ 0 and the boundary value of scalar field Jφ is below some value, then the entropy bound and thermodynamical stability do exist. When either condition on the parameters does not hold, however, thermodynamical stability is (partially) broken. The properties of the system and the relation between BG instantons and the breakdown are discussed in detail.


Pramana ◽  
2021 ◽  
Vol 95 (3) ◽  
Author(s):  
H R Chothe ◽  
G Saxena ◽  
S Somorendro Singh

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1568 ◽  
Author(s):  
Luis Herrera ◽  
Alicia Di Prisco ◽  
Justo Ospino

We study the general properties of dissipative fluid distributions endowed with hyperbolical symmetry. Their physical properties are analyzed in detail. It is shown that the energy density is necessarily negative, and the central region cannot be attained by any fluid element. We describe this inner region by a vacuum cavity around the center. By assuming a causal transport equation some interesting thermodynamical properties of these fluids are found. Several exact analytical solutions, which evolve in the quasi–homologous regime and satisfy the vanishing complexity factor condition, are exhibited.


2021 ◽  
Vol 127 ◽  
pp. 108495 ◽  
Author(s):  
A.K. Kushwaha ◽  
S.P. Mishra ◽  
M.K. Vishwakarma ◽  
Shivali Chauhan ◽  
Hamad R. Jappor ◽  
...  

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