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Heat capacity of cheese

Determination or calculation?

Journal of Thermal Analysis and Calorimetry
Authors: S. Heidenreich, T. Langner, and H. Rohm

Abstract  

The heat capacity of several samples of hard cheese, semi-hard cheese and soft cheese was determined by conventional differential scanning calorimetry (DSC) and by temperature modulated DSC. Additionally, the gross composition of the cheeses was analysed, and equations from the literature were used to calculate the heat capacity therefrom. Both analytical methods were suitable to determine the heat capacity of the cheese samples whereas only one out of three equations proposed for the calculation of the heat capacity of foods from composition data led to results which were comparable with analytical data. As the equation coefficients for particular constituents are responsible for the deviations in the calculated heat capacities the differences between calculated and measured values increase with a decreasing moisture content of the cheeses.

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. Matsui , Y. 1987 J. Nucl. Mater. 148 230 – 230 . 10.1016/0022-3115(87)90119-X . 4 Kohli , R. , Heat Capacity

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Journal of Thermal Analysis and Calorimetry
Authors: Iwona Zięborak-Tomaszkiewicz, Ewa Utzig, and P. Gierycz

Abstract  

The heat capacity of gallium nitride has been measured by DSC method using DuPont Thermal Analyst 2100, DSC 951 unit in the temperature range (300–850 K). The temperature dependence of the heat capacity can be presented in the following form: C p=32.960+0.162·10−1 T+2360170T −2-775370000T −3.

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Journal of Thermal Analysis and Calorimetry
Authors: Iwona Zięborak-Tomaszkiewicz, R. Świerzewski, and P. Gierycz

Abstract  

The heat capacity of the solid indium nitride was measured, using the Calvet TG-DSC 111 differential scanning microcalorimeter (Setaram, France), in the temperature between (314–978 K). The temperature dependence of the heat capacity can be presented in the following form: C p=41.400+0.499·10−3 T−135502T −2−26169900 T −3.

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Abstract  

Conventional thermodynamic expression predicts that the isobaric heat capacity decreases with increasing pressure. In model calculations, heat capacity increases with pressure, decreases, or remains insensitive to pressure, depending on the model applied. The expression cannot be applied to the gases, but experimental data on gases show evidently that heat capacity increases with pressure. Considering the change in enthalpy along two different paths with identical starting and ending points, we derive new expression dC P/dPV, where α is the volume coefficient of thermal expansion and V is the molar volume. The expression predicts the increase in C P with pressure and can be applied to gases. The test of the new expression against accurate literature data on the heat capacity of air, gaseous and liquid, demonstrates its validity.

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Abstract  

Heat capacity C p(T) of dysprosium diboride is experimentally investigated at the temperatures of 5–300 K. On the dependence C p(T) smooth anomaly at the temperatures of 15–20 K and sharp anomalies at T m1=47.8 K and T m2=178.8 K are revealed. Anomaly at T m1 is caused, obviously, by ferromagnetic phase transition in DyB2. The lattice contribution to DyB2 heat capacity is determined by comparison with heat capacity of non-magnetic YB2. The estimation of Schottky contribution to DyB2 heat capacity is made, the scheme of splitting of the ground state of Dy3+ ion is offered.

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Abstract  

The heat capacity of 9.70 and 11.35 mol% yttria stabilized zirconia ((ZrO2)1–x(Y2O3)x; x=0.0970, 0.1135) was measured by adiabatic calorimetry between 13 and 300 K, and some thermodynamic functions were calculated and given in a table. A large excess heat capacity extending from the lowest temperature to room temperature with a broad maximum at about 75 K was found in comparison with the heat capacity calculated from those of pure zirconia and yttria on the basis of simple additivity rule. The shape of the excess heat capacity is very similar to the Schottky anomaly, which may be attributed to a softening of lattice vibration. The amount of the excess heat capacity decreased with increasing yttria doping, while the maximum temperature did not vary. The relationships among the excess heat capacity, defect structure and interatomic force constants, and also the role of oxygen vacancy were discussed.

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Heat capacity and phonon spectra of A IIIN

Experiment and calculation

Journal of Thermal Analysis and Calorimetry
Authors: D. Sedmidubský, J. Leitner, P. Svoboda, Z. Sofer, and J. Macháček

Abstract  

The low temperature heat capacities of three A IIInitrides, A III=Al, Ga and In, were measured by relaxation method in the temperature range 2–300 K and the corresponding entropies at the reference temperature 298.15 K were evaluated from the experimental data. The lattice heat capacity at constant volume was also assessed theoretically within harmonic crystal approximation by direct method using a combination of VASP software package to obtain the Hellmann-Feynman forces and the Phonon program to calculate the phonon spectra. The experimental data were analyzed by means of a Debye-Einstein model taking use of the calculated heat capacity and involving additionally an anharmonic contribution.

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Low-temperature heat capacity of diglycylglycine

Some summaries and forecasts for the heat capacity of amino acids and peptides

Journal of Thermal Analysis and Calorimetry
Authors: V. Drebushchak, Yulia Kovalevskaya, I. Paukov, and Elena Boldyreva

Abstract  

Heat capacity of tripeptide diglycylglycine was measured in a temperature range from 6.5 to 304 K. The results were compared with those for glycine and glycylglycine. Peptide bonding was found not to change C P(T) virtually above 70 K, where heat capacity does not obey the Debye model. Comparison with literature data allows one to expect a significant difference in the heat capacity for enantiomorph and racemic species of valine and leucine, like it was found recently for D-and DL-serine.

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Abstract  

Synthetic enstatite MgSiO3 was crystallized from a melt, quenched into water, and then annealed at 873 K. The product is the monoclinic polymorph with the unit cell parameters of a=0.9619(7), b=0.8832(3), c=0.5177(4) nm, β=108.27(5)°. Heat capacity was measured from 6 to 305 K using an adiabatic vacuum calorimeter. Thermodynamic functions for clinoenstatite differ by about 5% from those predicted after a thermodynamic model in the literature, but are very close to those measured for orthorhombic enstatite.

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