Thermodynamic Characteristics of the Resolvation of Glycylglycinate Ions and Their Contribution to the Change in Stability of Complexes with Cu(II) and Ni(II) in Aqueous–Organic Solvents

ABSTRACT A series of organic solvents and phenol derivatives have been examined for the extraction of the pink Kober-colour complex. Optimal results could be achieved for fluorimetry by a solution of 2 % (w/v) p-nitrophenol and 1 % (v/v) ethanol in acetylenetetrabromide, when the green mercury line (546 mμ was used as primary light. The sensitivity, stability and specificity have been improved, compared with the previously described reaction. By changing the sequence of purification steps and by reducing the volume of the urine sample (5 ml) the method for the determination of total oestrogens has been simplified. Approximately 10 determinations can be done within 3–4 hours by one person. Recovery experiments and comparative determinations with a previously described method have been carried out. The excretion of total oestrogens in a complete menstrual cycle is determined with the described method.

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ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

Alternative Energy and Ecology (ISJAEE) ◽

10.15518/isjaee.2019.01-03.056-066 ◽

2019 ◽

pp. 56-66

Author(s):

I. Khidirov ◽

V. V. Getmanskiy ◽

A. S. Parpiev ◽

Sh. A. Makhmudov

Keyword(s):

Heat Capacity ◽

High Temperature ◽

Titanium Carbide ◽

Temperature Dependence ◽

Carbon Concentration ◽

Room Temperature ◽

Thermodynamic Characteristics ◽

Liquid Nitrogen Temperature ◽

Analysis Data ◽

Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

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