Structural transformations in porous glasses under mechanical loading. I. Tension

The evolution of porous structure and mechanical properties of binary glasses under tensile loading were examined using molecular dynamics simulations. We consider vitreous systems obtained in the process of phase separation after a rapid isochoric quench of a glass-forming liquid to a temperature below the glass transition. The porous structure in undeformed samples varies from a connected porous network to a random distribution of isolated pores upon increasing average glass density. We find that at small strain, the elastic modulus follows a power-law dependence on the average glass density and the pore size distribution remains nearly the same as in quiescent samples. Upon further loading, the pores become significantly deformed and coalesce into larger voids that leads to formation of system-spanning empty regions associated with breaking of the material.Comment: 27 pages, 13 figure

Distributions of pore sizes and atomic densities in binary glasses revealed by molecular dynamics simulations

We report on the results of a molecular dynamics simulation study of binodal glassy systems, formed in the process of isochoric rapid quenching from a high-temperature fluid phase. The transition to vitreous state occurs due to concurrent spinodal decomposition and solidification of the matter. The study is focused on topographies of the porous solid structures and their dependence on temperature and average density. To quantify the pore-size distributions, we put forth a scaling relation that provides a robust data collapse in systems with high porosity. We also find that the local density of glassy phases is broadly distributed, and, with increasing average glass density, a distinct peak in the local density distribution is displaced toward higher values.Comment: 22 pages, 6 figure

Structural transformations in porous glasses under mechanical loading. II. Compression

The role of porous structure and glass density in response to compressive deformation of amorphous materials is investigated via molecular dynamics simulations. The disordered, porous structures were prepared by quenching a high-temperature binary mixture below the glass transition into the phase coexistence region. With decreasing average glass density, the pore morphology in quiescent samples varies from a random distribution of compact voids to a porous network embedded in a continuous glass phase. We find that during compressive loading at constant volume, the porous structure is linearly transformed in the elastic regime and the elastic modulus follows a power-law increase as a function of the average glass density. Upon further compression, pores deform significantly and coalesce into large voids leading to formation of domains with nearly homogeneous glass phase, which provides an enhanced resistance to deformation at high strain.Comment: 25 pages, 12 figure

Evolution of the pore size distribution in sheared binary glasses

Molecular dynamics simulations are carried out to investigate mechanical properties and porous structure of binary glasses subjected to steady shear. The model vitreous systems were prepared via thermal quench at constant volume to a temperature well below the glass transition. The quiescent samples are characterized by a relatively narrow pore size distribution whose mean size is larger at lower glass densities. We find that in the linear regime of deformation, the shear modulus is a strong function of porosity, and the individual pores become slightly stretched while their structural topology remains unaffected. By contrast, with further increasing strain, the shear stress saturates to a density-dependent plateau value, which is accompanied by pore coalescence and a gradual development of a broader pore size distribution with a discrete set of peaks at large length scales.Comment: 30 pages, 16 figure

The influence of periodic shear on structural relaxation and pore redistribution in binary glasses

The evolution of porous structure, potential energy and local density in binary glasses under oscillatory shear deformation is investigated using molecular dynamics simulations. The porous glasses were initially prepared via a rapid thermal quench from the liquid state across the glass transition and allowed to phase separate and solidify at constant volume, thus producing an extended porous network in an amorphous solid. We find that under periodic shear, the potential energy decreases over consecutive cycles due to gradual rearrangement of the glassy material, and the minimum of the potential energy after thousands of shear cycles is lower at larger strain amplitudes. Moreover, with increasing cycle number, the pore size distributions become more skewed toward larger length scales where a distinct peak is developed and the peak intensity is enhanced at larger strain amplitudes. The numerical analysis of the local density distribution functions demonstrates that cyclic loading leads to formation of higher density solid domains and homogenization of the glass phase with reduced density.Comment: 23 pages, 10 figure

Formation of an integrated financial regulation system of transport corporations’ economic development

Scientific findings of this article correspond with the fact that the development of interacting business entities is quite diverse. This affects the efficiency of corporations’ budget management. So, a need arises to adjust the financial assets applied to the development of integrated enterprises, basing on their economic compatibility evaluation. Authors suggest using the companies’ development intensity determined by the increasing qualitative business activity indicators compared to the increasing quantitative ones. Theoretical economics gives no clear definition of compatibility of developing companies. Economic practices do not pay proper attention to the development of effective financial regulation of economic development of companies integrated into a corporation. The article suggests original definitions of economic compatibility as well as the model of forming the integrated system of transport companies’ economic development on the basis of morphological approach. Theoretical and methodological findings are approved in the business activity of transport corporationspeer-reviewe

PROSECUTOR’S SUPERVISION OVER THE ACTIVITIES OF THE BODIES OF PRELIMINARY INVESTIGATION ON COMPENSATION FOR DAMAGE CAUSED BY A CRIME AT THE STAGE OF INITIATING A CRIMINAL CASE

Aim: The article is devoted to the consideration of the essence and main directions of prosecutorial supervision over the activities of officials of the preliminary investigation bodies for compensation for harm caused by a crime at the stage of initiating a criminal case. According to the deep conviction of the authors, one of the directions for ensuring the rights and legitimate interests of victims of crimes is to ensure compensation for property and physical damage, as well as compensation for moral damage and damage to business reputation. This area of activity of the preliminary investigation bodies is no less important than bringing the perpetrators to justice in order to assign them a fair punishment. Results: The author identified some reasons that negatively affect the implementation of prosecutorial supervision over the activities of these participants in criminal proceedings to ensure compensation for harm caused by a crime at the stage of pre-investigation verification. Conclusion: In conclusion, the authors substantiate the conclusion that at present, prosecutorial supervision over the activities of officials of the bodies of preliminary investigation is relevant and especially in demand to ensure the principle of competitiveness of the parties, the creation of legal guarantees for the realization by persons who have become victims of criminal acts, the right to full compensation for the harm caused. Prosecutorial supervision is proposed to be regarded as an important dominant of the procedural function of prosecutors, aimed at preventing violations in the activities of the preliminary investigation and inquiry bodies to compensate for harm caused by criminal acts, starting from the stage of initiating a criminal case

Dephosphorization of Manganese Ore Raw Materials

The dephosphorization of manganese ores and concentrates in a reducing atmosphere is thermodynamically analyzed. It is shown that phosphorus can completely pass to a gas phase in a closed reaction system in a wide temperature range (1273–2073 K) at the amounts of a reducing gas (CO) that exceed the stoichiometric minimum required for reduction reactions. The gaseous products of reduction is found to contain phosphorus in the form of mainly polyatomic “heavy” molecular oxides, which can decrease the real effect of dephosphorization as compared to that obtained by equilibrium calculations because of kinetic factors. A thermodynamic simulation of a flow reaction system shows that almost complete transition of phosphorus to light gaseous substances (PO, P2) is thermodynamically possible at the temperatures that are close to the technological operation temperatures. This transition is provided by the ratio of the rate of formation of volatile phosphorus-containing substances to the rate of their removal from reaction regions. Keywords: manganese ores, manganese concentrates, phosphorus, carbon monoxide, reductio