scholarly journals Calorimetric Research into the Heat Capacity of Novel Nano-Sized Cobalt(Nickelite)-Cuprate-Manganites of LaBaMeIICuMnO6 (MeII = Co, Ni) and their Thermodynamic Properties

2020 ◽  
Vol 22 (1) ◽  
pp. 27
Author(s):  
B.K. Kassenov ◽  
Sh.B. Kassenova ◽  
Zh.I. Sagintaeva ◽  
E.E. Kuanyshbekov ◽  
M.O. Turtubaeva
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Calculated Data ◽  
Heat Capacities ◽  
Fundamental Constants ◽  
Debye Theory ◽  
Standard Heat ◽  
Standard Heat Capacity ◽  
Dynamic Calorimetry ◽  
Temperature Dependences

The isobaric heat capacities of novel nano-sized cobalt-cuprate-manganite of lanthanum and barium LaBaCoCuMnO6 and nickel-cuprate-manganite of lanthanum and barium LaBaNiCuMnO6 were investigated by dynamic calorimetry over the temperature range of 298.15‒673 K. It is found that a λ-shaped effect is observed on the curve of the heat capacity dependence on temperature of LaBaCoCuMnO6 at 523 K, while LaBaNiCuMnO6 also has a similar effect at 473 K. Equations for the temperature dependence of the heat capacity of cobalt(nickelite)-cuprate-manganite of lanthanum and barium are derived with allowance for the temperatures of phase transitions. Based on the experimental data, the fundamental constants ‒ the standard heat capacities of the compounds under study were found. Irrespective of the experimental data, we also calculated the standard heat capacities of the mentioned compounds using the Debye theory using the characteristic temperatures of the elements, their melting points, the Koref and Nernst-Lindemann equations. The obtained calculated data on C0p (298.15) of the compounds were in satisfactory agreement with the experimental data on the standard heat capacity. The standard entropies of LaBaCoCuMnO6 and LaBaNiCuMnO6 were calculated by the ion increment method. We calculated the temperature dependences of the enthalpy Ho(T)- Ho(298.15), entropy ΔSo(T), and the reduced thermodynamic potential ΔФ**(Т).

scholarly journals Calculation of the Isobaric Heat Capacities of the Liquid and Solid Phase of Organic Compounds at 298.15K by Means of the Group-Additivity Method

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1147
Author(s):  
Rudolf Naef
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Goodness Of Fit ◽  
Cross Validation ◽  
Solid Phase ◽  
Linear Equations ◽  
Heat Capacities ◽  
Molecular Volume ◽  
Complementary Method ◽  
Standard Deviations

The calculation of the isobaric heat capacities of the liquid and solid phase of molecules at 298.15 K is presented, applying a universal computer algorithm based on the atom-groups additivity method, using refined atom groups. The atom groups are defined as the molecules’ constituting atoms and their immediate neighbourhood. In addition, the hydroxy group of alcohols are further subdivided to take account of the different intermolecular interactions of primary, secondary, and tertiary alcohols. The evaluation of the groups’ contributions has been carried out by solving a matrix of simultaneous linear equations by means of the iterative Gauss–Seidel balancing calculus using experimental data from literature. Plausibility has been tested immediately after each fitting calculation using a 10-fold cross-validation procedure. For the heat capacity of liquids, the respective goodness of fit of the direct (r2) and the cross-validation calculations (q2) of 0.998 and 0.9975, and the respective standard deviations of 8.24 and 9.19 J/mol/K, together with a mean absolute percentage deviation (MAPD) of 2.66%, based on the experimental data of 1111 compounds, proves the excellent predictive applicability of the present method. The statistical values for the heat capacity of solids are only slightly inferior: for r2 and q2, the respective values are 0.9915 and 0.9874, the respective standard deviations are 12.21 and 14.23 J/mol/K, and the MAPD is 4.74%, based on 734 solids. The predicted heat capacities for a series of liquid and solid compounds have been directly compared to those received by a complementary method based on the "true" molecular volume and their deviations have been elucidated.

A study of the electrolytic solution process using the scaled particle theory. 5. Heat capacity of aqueous ions at elevated temperatures

1991 ◽  
Vol 69 (3) ◽  
pp. 440-450
Author(s):  
Utpal Sen
Keyword(s):  
Heat Capacity ◽  
Elevated Temperatures ◽  
Solution Process ◽  
Scaled Particle Theory ◽  
Thermodynamic Quantities ◽  
Particle Theory ◽  
Standard Heat ◽  
Born Model ◽  
Standard Heat Capacity ◽  
Aqueous Ions

A theory composite of the scaled particle theory and the Born model of solvent continuum has been used to theoretically calculate the standard heat capacity of hydration as well as the partial molal heat capacity of aqueous ions and electrolytes at elevated temperatures. The uncertainties in the second temperature derivatives of solvent dielectric constant at various temperatures present a barrier to an accurate heat capacity prediction by the theory. Nevertheless, the agreement between the predicted standard heat capacity of electrolytes in solution and the corresponding experimental data, particularly at higher temperatures, is encouraging. Moreover, the composite theory seems to provide the most accurate thermodynamic predictions to date for aqueous electrolytes at higher temperatures without involving any arbitrary adjustable parameter. We therefore use this theory to find the proper ionic scale of the partial molal heat capacities at elevated temperatures. Key words: scaled particle theory, solvent continuum model of Born, standard heat capacity of aqueous ions, absolute scale for hydration thermodynamic quantities.

scholarly journals SYNTHESIS AND STUDY OF THERMODYNAMIC PROPERTIES OF NEW ZINCATE-MANGANITES NdM2IIZnMnO6 (MII − Mg, Ca)

2018 ◽  
Vol 61 (3) ◽  
pp. 16
Author(s):  
Bulat К. Kasenov ◽  
Shuga B. Kasenova ◽  
Zhenisgul I. Sagintaeva ◽  
Yerbolat Y. Kuanyshbekov ◽  
Meruert O. Turtubaeva
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
Ceramic Technology ◽  
Cell Parameters ◽  
Dynamic Calorimetry ◽  
Temperature Dependences ◽  
Calorimetric Studies ◽  
Experimental Values

Zincate-manganites with the composition NdM2IIZnMnO6 (MII− Mg, Ca) were synthesized using ceramic technology from oxides of Nd (III), Zn (II), Mn (III) and carbonates of alkaline-earth metals - magnesium and calcium. X-ray patterns of the prepared substancies were measured on a DRON-2.0 diffractometer. We established that they crystallize in the cubic system with the following unit cell parameters: NdMg2ZnMnO6 – а=13.927±0.035 Å, Z = 4, V0 = 2701.36±0.11 Å3, V0el.cell. = 675.34±0.03 Å3, ρX-ray = 4.20, ρpycn. = 4.19±0.01 g/cm3; NdCa2ZnMnO6 – а=13.910±0.030 Å, Z = 4, V0 = 2691.45±0.10 Å3, V0el.cell. = 672.86±0.03 Å3, ρX-ray = 4.04, ρpycn. = 4.01±0.08 g/сm3. The temperature dependence of the heat capacity of NdMg2ZnMnO6 and NdCa2ZnMnO6 was studied by dynamic calorimetry in the range of 298.15-673 K on the IT-S-400 calorimeter. Five parallel experiments were performed at each temperature point with 25 K step. The results were averaged and analyzed using mathematical statistics. As a result of calorimetric studies of the heat capacity, within the temperature range of 298.15-673 K, we discovered on the curves of the temperature dependence of heat capacity the phase transitions of the II kind at the following temperatures: 373, 548 К- NdMg2ZnMnO6, 448, 573 К – NdCa2ZnMnO6. These phase transitions were probably due to Schottky effects -the transition from semiconductivity to metallic conductivity, and variations in capacity, dielectric permittivity, the occurrence of Curie or Neel points. The equations of the temperature dependence of the heat capacity were derived on the basis of the experimental values with account the temperatures of the phase transitions. By the ion increment method, we calculated the standard entropies of the compounds investigated. We calculated the temperature dependences of С°р(Т) and thermodynamic functions Н°(Т)-Н°(298.15), S°(T) and Фхх(Т).Forcitation:Kasenov B.K., Kasenova Sh.B., Sagintaeva Zh.I., Kuanyshbekov Е.Е., Turtubaeva М.О. Synthesis and study of thermodynamic properties of new zincate-manganites NdM2IIZnMnO6 (MII − Mg, Ca). Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 16-20

THERMODYNAMIC PROPERTIES OF MC (M = V, Nb, Ta): FIRST-PRINCIPLES CALCULATIONS

2013 ◽  
Vol 27 (19) ◽  
pp. 1341035 ◽  
Author(s):  
YONG CAO ◽  
JINGCHUAN ZHU ◽  
YONG LIU ◽  
ZHISHEN LONG
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Linear Expansion ◽  
Debye Model ◽  
Linear Expansion Coefficient ◽  
First Principles Calculations ◽  
Temperature Dependences

Through the quasi-harmonic Debye model, the pressure and temperature dependences of linear expansion coefficient, bulk modulus, Debye temperature and heat capacity have been investigated. The calculated thermodynamic properties were compared with experimental data and satisfactory agreement is reached.

scholarly journals Mean-field parameters of some PrxTb(1-x)Al2 compounds found via searching for the best magnetic heat capacity fitting

2021 ◽  
Vol 2090 (1) ◽  
pp. 012081
Author(s):  
J. C. G. Tedesco ◽  
V.J. Monteiro ◽  
A. M. G. Carvalho ◽  
L.P. Cardoso ◽  
A. A. Coelho
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Magnetocaloric Effect ◽  
Mean Field ◽  
Heat Capacities ◽  
Field Approach ◽  
Physical Limitations ◽  
The Mean ◽  
Good Agreement

Abstract Simulations of the magnetic heat capacity of some (Pr, Tb)Al2 compounds were performed using the mean-field approach. The developed routine aims to optimize the set of mean-field parameters. The proposed algorithm calculates the sum of squared differences between the experimental points and the simulated curve and then changes the parameters in order to minimize this sum. This searching leads to consistent values that can reproduce the experimental data. The parameters found in this work reproduced the heat capacities curves of the PrxTb(1−x)Al2 compounds, x=0.25, x=0.50 and x=0.75, with good agreement. The physical limitations of the mean-field approach do not preclude analysing the results. These parameters are important because they can help to understand and calculate the magnetocaloric effect these materials can present.

scholarly journals Prediction of Standard Heat Capacity and Entropy of Inorganic XY3, XY4 and XY5 Gases at 25 degrees C Based on Correlation with the Normal Boiling Point.

1989 ◽  
Vol 43 ◽  
pp. 758-762 ◽  
Author(s):  
Reidar Stølevik ◽  
I. G. Krogh Andersen ◽  
G. Ploug-Sørensen ◽  
Ewa Huskowska ◽  
Mauri Lounasmaa ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Boiling Point ◽  
Normal Boiling Point ◽  
Standard Heat ◽  
Standard Heat Capacity

scholarly journals Saturated-liquid heat capacity: New polynomial models and review of the literature experimental data

2003 ◽  
Vol 68 (6) ◽  
pp. 479-495 ◽  
Author(s):  
Jovan Jovanovic ◽  
Dusan Grozdanic
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Heat Capacities ◽  
Review Of The Literature ◽  
Saturated Liquid ◽  
Correlation Models ◽  
Polynomial Models ◽  
Liquid Heat

In this paper a review of selected literature experimental data for saturated-liquid heat capacities was presented. Two-, three- and four-parameter polynomial correlation models are tested on those data. Obtained results lead to the conclusion that correlation quality depends on the number of parameters, and slightly on the type of models. The best two three- and four-parameter models were proposed.

Heat Capacity of the Rb3LnCl6 Compounds with Ln = La, Ce, Pr, Nd

1999 ◽  
Vol 54 (6-7) ◽  
pp. 397-403 ◽  
Author(s):  
L. Rycerz ◽  
M. Gaune-Escard
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Liquid Phase ◽  
Formation Enthalpy ◽  
Heat Capacities ◽  
Small Decrease ◽  
Scanning Calorimetry ◽  
Increasing Temperature

Abstract The heat capacities of the solid and liquid Rb3LnCl6 compounds, where Ln = La, Ce, Pr, Nd, have been determined by differential scanning calorimetry (DSC) in the temperature range 300 -1100 K. The heat capacity shows a small decrease with increasing temperature from the temperature of phase transition up to 150 -200 K above this transition for the Rb3CeCl6, Rb3PrCl6 and Rb3NdCl6 compounds. The measured heat capacities were used to calculate the formation enthalpy of the liquid phase. The results obtained compare satisfactorily with the known experimental data.

Heat Capacity of K3LnCl6 Compounds with Ln = La, Ce, Pr, Nd

1999 ◽  
Vol 54 (3-4) ◽  
pp. 229-235 ◽  
Author(s):  
M. Gaune-Escard ◽  
L. Rycerz
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Heat Capacities ◽  
Scanning Calorimetry ◽  
The Enthalpy Of Formation

The heat capacities of the solid and liquid K3LnCl6 compounds (Ln = La, Ce, Pr, Nd) have been determined by differential scanning calorimetry (DSC) in the temperature range 300 -1100 K. Their temperature dependence is discussed in terms of the phase transitions of these compounds as reported in literature. The heat capacity increases and decreases strongly in the vicinity of a phase transition but else varies smoothly. The Cp data were fitted by an equation which provides a satisfactory representation up to the temperatures of Cp discontinuity. The measured heat capacities were checked for consistency by calculating the enthalpy of formation of the liquid phase, which had been previously measured. The results obtained compare satisfactorily with these experimental data.

Calorimetric and Thermodynamic Studies of Complex Ferrites

2016 ◽  
Vol 835 ◽  
pp. 260-264
Author(s):  
Mukhametkali Musagalievich Mataev ◽  
M.R. Abdraimova ◽  
Zh.D. Batyrbekova ◽  
A.M. Madiyarova
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Functions ◽  
Polynomial Equation ◽  
Data Bank ◽  
Type Ii ◽  
Dynamic Calorimetry ◽  
Temperature Ranges ◽  
Standard Values ◽  
Mathematical Processing

By method of dynamic calorimetry, in the temperature range between 298,15 and 673 K, isobaric heat capacity of polycrystalline ferrites Bі2СаFe4O10, BіMgFe2O5.5, Bі2MgFe4O10 was experimentally studied. Mathematical processing of experimental data made it possible to derive polynomial equation of temperature dependence of ferrites heat capacity for respective temperature ranges, in dependencies C0p~f (T) of ferrite Bі2СаFe4O10 a jump was detected in heat capacity at 625K associated with phase transitions of type II. The values of the thermodynamic functions C0p(Т), H0(T) – Н0(298,15), C0(T), Fhh(Т) have been calculated. Standard values of thermodynamic functions were determined using the method of ion increments. The results obtained broaden thermodynamic data bank for complex inorganic crystalline compounds.

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