The Minima of Viscosities.

The Trachenko-Brazhkin equation of the minimal possible viscosity is analysed, emphasising its validity by the account of multibody interactions between flowing species through some effective masses replacing their true (bare) masses. Pressure affects the effective masses, decreasing them and shifting the minimal viscosity and the temperature at which it is attained to higher values. The analysis shows that effective masses in the Trachenko-Brazhkin equation are typically lighter compared bare masses; e.

On Crossover Temperatures of Viscous Flow Related to Structural Rearrangements in Liquids.

An additional crossover of viscous flow in liquids occurs at a temperature above the known non-Arrhenius to Arrhenius crossover temperature (). is the temperature when the minimum possible viscosity value is attained, and the flow becomes non-activated with a further increase in temperature. Explicit equations are proposed for the assessments of both and , which are shown to provide data that are close to those experimentally measured.

NiTi, a New Liquid Glass.

Many endothermic liquid-liquid transitions, occurring at a temperature T above the melting temperature T, are related to previous exothermic transitions, occurring at a temperature T after glass formation below T, with or without attached crystallization and predicted by the nonclassical homogenous nucleation equation. A new thermodynamic phase composed of broken bonds (configurons), driven by percolation thresholds, varying from ~0.145 to Δε, is formed at T with a constant enthalpy up to T.

The Flow of Glasses and Glass-Liquid Transition under Electron Irradiation.

Recent discovery and investigation of the flow of glasses under the electron beams of transmission electron microscopes raised the question of eventual occurrence of such type effects in the vitrified highly radioactive nuclear waste (HLW). In connection to this, we analyse here the flow of glasses and glass-liquid transition in conditions of continuous electron irradiation such as under the e-beam of transmission electron microscopes (TEM) utilising the configuron (broken chemical bond) concept and configuron percolation theory (CPT) methods. It is shown that in such conditions, the fluidity of glasses always increases with a substantial decrease in activation energy of flow at low temperatures and that the main parameter that controls this behaviour is the dose rate of absorbed radiation in the glass.

Zirconolite Polytypes and Murataite Polysomes in Matrices for the REE-Actinide Fraction of HLW.

Electron backscatter diffraction (EBSD) has been used for more than 30 years for analyzing the structure of minerals and artificial substances. In recent times, EBSD has been widely applied for investigation of irradiated nuclear fuel and matrices for the immobilization of radioactive waste. The combination of EBSD and scanning electron microscopy (SEM/EDS) methods allows researchers to obtain simultaneously data on a specimen's local composition and structure.