Method for the Estimation of Standard Entropy of Crystal Phases at 298.15 K on the Limited Temperature Range of Heat Capacity Measurements

2015 ◽  
Vol 60 (8) ◽  
pp. 2320-2328 ◽  
Author(s):  
Irina A. Uspenskaya ◽  
Leonid A. Kulikov
Keyword(s):  
Heat Capacity ◽  
Standard Entropy ◽  
Temperature Range ◽  
Limited Temperature ◽  
Limited Temperature Range ◽  
Crystal Phases ◽  
Heat Capacity Measurements

Reduction of binary sulfate mixtures containing CuSO4 by H2

1976 ◽  
Vol 54 (23) ◽  
pp. 3651-3657 ◽  
Author(s):  
Fathi Habashi ◽  
Shaheer A. Mikhail
Keyword(s):  
Intermediate Product ◽  
The Other ◽  
Temperature Range ◽  
Other Hand ◽  
First Case ◽  
Limited Temperature ◽  
Limited Temperature Range ◽  
The Individual

The reduction of a binary sulfate mixture cannot be predicted from the behavior of the individual components. Thus, while CuSO4 is reduced to Cu at 400 °C and NiSO4 is reduced to Ni3S2, the sulfate mixture yields Cu, Ni3S2, and Cu2S. Also while FeSO4 is completely stable in H2 at 400 °C, (Cu,Fe) SO4 yields Cu and Cu5FeS4. The formation of Cu2S in the first case and Cu5FeS4 in the second was unexpected. On the other hand, (Cu,Mn)SO4 is stable in H2 up to 550 °C although pure CuSO4 is completely reduced at 400 °C. CoSO4 also interferes when reduced in presence of CuSO4, while Na2SO4, MgSO4, Al2(SO4)3, ZnSO4, CdSO4 do not interfere within limited temperature range. Of these only Na2SO4 forms a complex sulfate with CuSO4. No Cu2SO4 was identified when CuSO4 was reduced in presence of other sulfates although it is an intermediate product during the reduction of pure CuSO4.

Heat capacity measurements of CaAlSiO4F from 5 to 850 K and its standard entropy

2018 ◽  
Vol 103 (7) ◽  
pp. 1165-1168 ◽  
Author(s):  
Peter Tropper ◽  
Ulrike Troitzsch ◽  
Edgar Dachs ◽  
Artur Benisek
Keyword(s):  
Heat Capacity ◽  
Standard Entropy ◽  
Heat Capacity Measurements

scholarly journals Phase Transitions and Local Polarity above TC in a PbZr0.87Ti0.13O3 Single Crystal

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 286
Author(s):  
Iwona Lazar ◽  
Andrzej Majchrowski ◽  
Andrzej Soszyński ◽  
Krystian Roleder
Keyword(s):  
Phase Transitions ◽  
Solid Solutions ◽  
Piezoelectric Materials ◽  
Temperature Range ◽  
Limited Temperature ◽  
Similar Chemical ◽  
Limited Temperature Range ◽  
Optical Dielectric ◽  
Top Seeded Solution Growth ◽  
First Time

Solid solutions of PbZr1−xTixO3 (PZT) are one of the most widely used piezoelectric materials with perovskite structure. Despite the decades of research, the phase diagram of PZT reported in 1971 has not been resolved yet. Recently, it turned out that single crystals of good quality of these solid solutions can be grown. By means of top-seeded solution growth (TSSG) technique, we succeeded to grow a single PbZr0.87Ti0.13O3 crystal. Hence, a partial verification of the diagram could be performed through investigations of the optical, dielectric, pyroelectric and elastic properties of this crystal, in a wide temperature range. The obtained results confirmed that the PbZr0.87Ti0.13O3 crystal undergoes a sequence of phase transitions, such as those observed in ceramics of similar chemical composition. However, additional anomalies of investigated physical properties were observed and discussed. Moreover, the influence of electric field on optical properties has been investigated for the first time and has proven the existence of local polar character of the phase above TC in a limited temperature range.

HEAT CAPACITY MEASUREMENTS ON GELATIN GELS. II.

1934 ◽  
Vol 10 (4) ◽  
pp. 452-462 ◽  
Author(s):  
W. F. Hampton ◽  
J. H. Mennie
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Heat Effect ◽  
Freezing Point ◽  
Temperature Range ◽  
Calorimetric Measurements ◽  
Gelatin Gels ◽  
Heat Capacity Measurements

Measurements of the heat capacity of gelatin gels, prepared from ash-free, electric gelatin, have been extended to cover the temperature range between − 180° and 25 °C. and the concentration range from 9 to 100% gelatin. Change in the temperature of the gel above the freezing point is found to be accompanied by a heat effect which has not previously been taken into account in calorimetric measurements on gels and which renders the interpretation of the experimental data uncertain.

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