Role of Liquid-Liquid Phase Transitions in Mechanism of Erythrocyte Protection During Cooling with CRIHBT-115 Cryopreservative Agent

The presence in the system of critical liquid-liquid phase transition (PT) by the mechanism, resulting in formation of dispersion system, namely high-concentrated emulsion, has been established here during cooling when using polarized light microscopy and fixation of critical opalescence phenomenon in erythrocyte concentrate with glycerol-containing cryopreservative agent, designed at the Central Research Institute of Haematology and Blood Transfusion (Russia) (CRIHBT-115 ). The studied cryobiological system displayed no signs of crystallization. A phase behaviour of cryopreservative and supernatant has been studied during cooling-warming cycle. Changes in the volume of cryopreservative and erythrocyte concentrate were comparatively and qualitatively evaluated during cooling. The mechanism of protective action of cryopreservation solution has been determined. The similarity between physical and chemical processes during cooling-warming of erythrocyte cytoplasm and garlic meristem cells (germinal plant tissue) when entering cold anabiosis has been established.

Heat transfer mode shift to adiabatic thermalization in near-critical carbon dioxide under terrestrial conditions

Heat transfer via acoustic waves is referred to as adiabatic thermalization or the piston effect. Until now, adiabatic thermalization was believed to be a secondary effect that mostly occurs under microgravity conditions and is readily overpowered by mixing due to gravitational forces. However, this work revealed that in microsystems, adiabatic thermalization is a dominant heat transfer mechanism. A substantial shift in thermalization modes from vaporization to acoustic waves was observed through critical opalescence temperature measurements of carbon dioxide (CO2). The contribution of the piston’s effect increased from 4.3–77.6% when the reduced pressure increased from 0.86 to 0.99. The findings are used to explain the observed heat transfer enhancement that occurred concurrently with the reduction in the void fraction. Revealing the nature of the piston effect to enhance heat transfer will advance copious technological fields like space exploration, fusion reactors, data centers, electronic devices, and sensing technology.

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.