Thermodynamic Functions of Terbium Hafnate

The molar heat capacity of terbium hafnate with a pyrochlore structure was measured by relaxation and adiabatic calorimetry. The smoothed values of the molar heat capacity were used to calculate the thermodynamic functions in the temperature range 6–330 K. The general form of the Schottky anomaly was determined.

Comparative analysis of the efficiency of optical and calorimetric methods for studying the near-critical state of hydrocarbon mixtures

By the example of a binary hydrocarbon methane–pentane mixture simulating the simplest gas-condensate system, it is shown that the optical method for studying the near-critical state of hydrocarbon fluid, using the measurement of the intensity of critical opalescence in the vicinity of the liquid–gas critical point, gives more accurate and reliable results for the dew–bubble curve and values of critical parameters of the fluid than classical adiabatic calorimetry, which uses the thermogram method to record the change in the phase state of the fluid in the near-critical region.