Powder Metallurgy Use of Waste from Bearing Production

A technology has been developed for improving the properties of ShKhl7 steel powder, obtained from bearing production waste sludge by familiar technological processes. On the basis of theoretical and experimental studies, we have ascertained the optimal conditions for ball milling, grinding, and heat treatment of the powders so as to improve their fluidity and bulk density. The technological and strength characteristics of the powders studied make them suitable for the production of serviceable parts by powder metallurgy methods.__________Translated from Poroshkovaya Metallurgiya, Nos. 1–2(441), pp. 106–112, January–February, 2005.     

Studying the active layer of oligotrophic bogs in the Taiga zone of Western Siberia

In this paper, we identify and describe the active and inert horizons of oligotrophic bogs. These often appear to be a fire risk to oil and gas extraction industries, but these bogs are a complex biological system also. We describe three structural layers for the active horizon. These are the turf layer, the porous layer, the intermediate layer. We have investigated the morphological characteristics of these layers. For each layer, we gave the measurement of physical parameters – pH, general mineralisation, conductivity, coefficient of ash and moisture. In each selected layer we study microbiological parameters – microbial biomass, the carbon of microbial biomass, basal respiration and microbial metabolic quotient. Microbiological studies have established the boundary between the aerobic and anaerobic conditions in active layer of oligotrophic bogs. In each layer, we have established the biochemical characteristics of layers studying enzymes catalase and invertase. The obtained data make it possible to assess the functional processes in the active horizon of the wetland’s ecosystem.     

New hard ternary Hf–Ir–B borides formed by reaction hafnium diboride with iridium

A variety of the ternary Hf–Ir–B phases formed via the reaction between iridium and hafnium diboride at elevated temperatures was found. The data on the phase and elemental composition, as well as crystal structure, obtained by powder and single-crystal X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectrometer, and time-of-flight neutron diffraction analysis unambiguously confirm that HfIr₃B_x solid solution, two known ternary borides (HfIr₃B₄, Hf₂Ir₅B₂), as well as two novel ternary HfIr_2.1B_1.3 and HfIr_5.7B_2.7 phases, are formed at elevated temperatures. This result is fundamentally different from that previously obtained by us for the Hf–Ir–C system in which only one binary intermetallic compound, HfIr₃, was produced. The measured Vickers microhardness for all the aforementioned ternary borides (13–19 GPa) allows us to consider them hard. The coefficients of thermal expansion of ternary borides were measured by in situ high-temperature X-ray analysis.     

Mitochondrial Dysfunction and Chronic Inflammation in Polycystic Ovary Syndrome

Polycystic ovarian syndrome (PCOS) is the most common endocrine–metabolic disorder affecting a vast population worldwide; it is linked with anovulation, mitochondrial dysfunctions and hormonal disbalance. Mutations in mtDNA have been identified in PCOS patients and likely play an important role in PCOS aetiology and pathogenesis; however, their causative role in PCOS development requires further investigation. As a low-grade chronic inflammation disease, PCOS patients have permanently elevated levels of inflammatory markers (TNF-α, CRP, IL-6, IL-8, IL-18). In this review, we summarise recent data regarding the role of mtDNA mutations and mitochondrial malfunctions in PCOS pathogenesis. Furthermore, we discuss recent papers dedicated to the identification of novel biomarkers for early PCOS diagnosis. Finally, traditional and new mitochondria-targeted treatments are discussed. This review intends to emphasise the key role of oxidative stress and chronic inflammation in PCOS pathogenesis; however, the exact molecular mechanism is mostly unknown and requires further investigation.     

Comparison of the Effect of Horizontal Vibrations on Interfacial Waves in a Two-Layer System of Inviscid Liquids to Effective Gravity Inversion

We study the waves at the interface between two thin horizontal layers of immiscible liquids subject to high-frequency tangential vibrations. Nonlinear governing equations are derived for the cases of two- and three-dimensional flows and arbitrary ratio of layer thicknesses. The derivation is performed within the framework of the long-wavelength approximation, which is relevant as the linear instability of a thin-layers system is long-wavelength. The dynamics of equations is integrable and the equations themselves can be compared to the Boussinesq equation for the gravity waves in shallow water, which allows one to compare the action of the vibrational field to the action of the gravity and its possible effective inversion.     

The Interaction of Rigid Cylinders in a Low Reynolds Number Pulsational Flow

The interaction of two rigid cylinders with parallel axes in a viscous liquid subjected to translational vibrations perpendicular to the plane containing the cylinder axes is considered in the framework of the low Reynolds number approximation. It is shown that the interaction type substantially depends on the distance between the cylinders. If this distance exceeds the viscous Stokes length, then the vibrations lead to the cylinder attraction. For the distances shorter than the Stokes length, the behaviour is opposite.     

Dynamics of Particle Confined Between Oscillating and Fixed Walls

In this paper, we investigate the motion of a particle confined between the oscillating and fixed walls. As the particle collides with the moving wall in the phase of oscillations, when the wall velocity grows, the wall after collision catches up with the particle. This process can be repeated many times until in finite time interval the particle is found lying on the wall and continues its motion together with the wall. When the sign of the wall acceleration changes the particle detaches from the wall with zero velocity, so that it looks as if the particle “sticks” to the wall. It has been found that if the collision is inelastic, “sticking” leads to convergence of close trajectories except for the case of weak decay. On the contrary, in the case of elastic collision “sticking” of the particle causes even a more rapid divergence of theses trajectories.     

How To Form a Phosphate Anhydride Linkage in Nucleotide Derivatives

The fundamental roles of nucleoside triphosphates and nucleotide cofactors such as NAD⁺ in biochemistry are well known. In recent decades, continuing research has revealed the key role of 5′‐capped RNA and 5′,5′‐dinucleoside polyphosphates in the regulation of vitally important physiological processes. Last but not least, the commercial potential of nucleoside triphosphate synthesis can hardly be overestimated. Nevertheless, despite decades of investigation and the obvious topicality of the research on the chemical synthesis of the nucleotide compounds containing phosphate anhydride linkages, none of the existing procedures can be considered an up‐to‐date “gold standard”. However, there are a number of fruitful synthetic approaches to forming phosphate anhydride linkages in satisfactory yield. These are summarized in this concise review, organized by the type of active phosphorous intermediate and reagents used.     

Search for New Opportunities Modification Raschig,Schiff, Andrusov,Hofmann, Colbe and Delepine Reactions

We explored new approaches to replace the nitrogen atoms of arsenic, antimony, bismuth, and discovered a new paths to modify Raschig, Schiff, Andrusov, Hofmann, Colbe, Delepine reactions with arsine, stibine and bismuthine in organometallic chemistry. We have proposed a new mechanism for possible reactions.     

Convection in a Two-Layer System with a Deformable Interface Under Low Gravity Conditions

The onset of thermal convection in a system of two horizontal layers of immiscible liquids of similar densities is studied under low gravity conditions. A constant heat flux is prescribed at both rigid boundaries. A generalized Boussinesq approach that allows correct accounting for the interface deformation is used. The long-wave perturbations emerge under low-gravity conditions; either monotonic or oscillatory modes are critical depending on the problem. Moreover, two different modes of the monotonic instability exist. For the first instability mode, the convection dominates, whereas the interface remains nearly undeformable. The second monotonic instability mode is substantially related to interface deformations. The system of non-linear amplitude equations describing the behavior of long-wave regimes at finite-amplitude interface deflection and finite supercriticalities is obtained. The analytical and numerical investigations of these equations show that the stable non-trivial stationary solutions are absent, and after a transient at least one of the layers is split into the areas not connected to each other. The nonlinear regimes of cellular convection are studied numerically by the Level Set method.