PHYSICA CONDITINS OF THE ‘LIGHT’ CORE FORMATION AND THERMONUCLEAR HEAT SOURCE DEEP INSIDE THE EARTH

Purpose. Experimental research into the physical model of the Earth’s core formation in the center of gas‑dust spiral vortex and numerical assessment of the physical conditions associated with the development of thermonuclear reactions in the Earth’s core. Methodology. Analysis of the main points of conventional conceptions, their principal merits and drawbacks which delineate their potential possibilities. Experimental studies implementing shock‑wave treatment of porous materials in cylindrical containers. Numerical assessment of the physical conditions that initiate thermonuclear reactions in the Earth’s core. Findings. It is extremely important to choose the model of the Earth formation with originally “light” core for several reasons. First, it provides a physically grounded mechanism of the thermonuclear heat source formation;second, the process of the Earth transition to equilibrium state inevitably creates conditions for mechanical, physical and chemical activity of elements in geospheres. Numerical assessment was performed to estimate the main conditions which are necessary for thermonuclear heating of the Earth’s central bulk – to determine the deuterium nuclei concentration and the respective temperatures. Originality. The authors suggested a model describing formation of the initially “light” core of the Earth. Experiments allowed studying some physical peculiarities of spiral vortices initiation and development. Regularities of change in plasma parameters, core temperature and thermonuclear energy release have been established in reference to the Earth’s age. Practical value. The obtained results will be useful for studying such important planetary geological phenomena as matter differentiation and formation of spheres inside the planet, as well as heat flow distribution in its bulk

ON FORMATION OF ELECTRICALLY CONDUCTIVE PHASES UNDER ELECTROTHERMAL ACTIVATION OF FERRUGINOUS CARBONATES

Purpose. Study of the formation of an electrically conductive phase in carbonates using siderite as an example and determination of the temperature dependence of its formation and silicon content during simultaneous heating and the action of a weak electric field. Methodology. Analysis and generalization of the results of experimental studies. Physicochemical analytical studies have been performed using electron and optical microscopy, petrographic and X-ray phase analysis, thermogravimetric analysis and differential scanning calorimetry, and gas chromatography. Phase equilibria in the “iron oxides – carbon – carbon oxides” system have been evaluated using data on the standard change in the Gibbs energy Evaluation. Findings. Formation of electrically conductive phases in siderite has been studied. The dependence of new phase formation on heating and the magnitude of the electric field strength have been determined. The regularities of the change in threshold temperatures of phase transitions in samples of siderite and calcite containing silicon impurities have been established. Originality. Due to the thermally stimulated increase in the concentration of mobile charge carriers in intergranular space, the electric field of point charges takes the prominent part in the formation of the end product of chemical reactions. The additional effect of electric current on the increasing destabilization of chemical bonds between surface atoms leads to the formation and transport of ions, to a decrease in the energy barrier of nuclei formation of the electrically conductive phase near the active centres. The abrupt increase in electrical conductivity is due to the spontaneous formation of the nuclei of a new phase and the transition of ionic conductivity to a mixed one or an electronic one primarily. A composite semiconductor is formed as a result of electrothermal activation of siderite. This semiconductor consists of a matrix-semiconductor representing the initial mineral and is penetrated by parallel-oriented highconductivity threads. Practical value. Experimental results show that such processes occurring in rock are quite real under the conditions of the earth’s crust, and the physical values of thermodynamic quantities (factors of metamorphism) are sometimes overestimated significantly in the interpretation of various geological events

ELECTRICAL ChARGES AS CATALySTS OF ChEMICAL REACTIONS ON A SOLID SuRFACE

Purpose. To determine the change dependency of the potential energy of the chemical bond of a diatomic molecule on the value of the point charge and its distance to the bond using quantum mechanical calculation. Methodology. Numerical simulation of a quantum mechanical system consisting of a point charge and a diatomic molecule interacting with each other. Findings. The quantum-mechanical problem of the effect of an external Coulomb center on the chemical bond of diatomic molecules is solved. Originality. A quantum mechanical model of a physical system consisting of three interacting Coulomb centers (there is a chemical bond between two of them) is developed. The model makes it possible to understand the dynamics of the interaction of a molecule with an ion, the charge of which can be characterized by either integers or fractional numbers. The change in the energy of the chemical bond in the ion field depending on the distance to the bond and the magnitude of the charge is established. Practical value. The developed technique for calculating the energy of a chemical bond as a function of the magnitude of the electric charge was used in the development of the method for growing single crystals of metastable diamond, in calculating the limits of the chemical bond stability in metal azides, in developing the way of additional harmful gases formation during rock blasting and in calculating the stability of nanoscale hydrocarbon chains in coal, and others. The method can be used to decide on the catalyst and control the catalytic reactions

Decomposition of PD-regulators design problem for systems with slow and fast modes

The PD-regulators design problem for the singularly perturbed control system is considered in the paper. It is shown that this problem can be reduced to the P-regulators design problems for two subsystems of lower dimension.The authors are supported by the Russian Foundation for Basic Research and Samara Region (project 16-41-630524-p) and the Ministry of Education and Science of the Russian Federation under the Competitiveness Enhancement Program of Samara University (2013-2020)

Development of a population-based microsimulation model of osteoarthritis in Canada

OBJECTIVES: The purpose of the study was to develop a population-based simulation model of osteoarthritis (OA) in Canada that can be used to quantify the future health and economic burden of OA under a range of scenarios for changes in the OA risk factors and treatments. In this article we describe the overall structure of the model, sources of data, derivation of key input parameters for the epidemiological component of the model, and preliminary validation studies. DESIGN: We used the Population Health Model (POHEM) platform to develop a stochastic continuous-time microsimulation model of physician-diagnosed OA. Incidence rates were calibrated to agree with administrative data for the province of British Columbia, Canada. The effect of obesity on OA incidence and the impact of OA on health-related quality of life (HRQL) were modeled using Canadian national surveys. RESULTS: Incidence rates of OA in the model increase approximately linearly with age in both sexes between the ages of 50 and 80 and plateau in the very old. In those aged 50+, the rates are substantially higher in women. At baseline, the prevalence of OA is 11.5%, 13.6% in women and 9.3% in men. The OA hazard ratios for obesity are 2.0 in women and 1.7 in men. The effect of OA diagnosis on HRQL, as measured by the Health Utilities Index Mark 3 (HUI3), is to reduce it by 0.10 in women and 0.14 in men. CONCLUSIONS: We describe the development of the first population-based microsimulation model of OA. Strengths of this model include the use of large population databases to derive the key parameters and the application of modern microsimulation technology. Limitations of the model reflect the limitations of administrative and survey data and gaps in the epidemiological and HRQL literature

Nephrotoxic effects of paraoxon in three rat models of acute intoxication

The Publisher's final version can be found by following the DOI link. Open access article.The delayed effects of acute intoxication by organophosphates (OPs) are poorly understood, and the various experimental animal models often do not take into account species characteristics. The principal biochemical feature of rodents is the presence of carboxylesterase in blood plasma, which is a target for OPs and can greatly distort their specific effects. The present study was designed to investigate the nephrotoxic effects of paraoxon (O,O-diethyl O-(4-nitrophenyl) phosphate, POX) using three models of acute poisoning in outbred Wistar rats. In the first model (M1, POX2x group), POX was administered twice at doses 110 µg/kg and 130 µg/kg subcutaneously, with an interval of 1 h. In the second model (M2, CBPOX group), 1 h prior to POX poisoning at a dose of 130 µg/kg subcutaneously, carboxylesterase activity was pre-inhibited by administration of specific inhibitor cresylbenzodioxaphosphorin oxide (CBDP, 3.3 mg/kg intraperitoneally). In the third model (M3), POX was administered subcutaneously just once at doses of LD16 (241 µg/kg), LD50 (250 µg/kg), and LD84 (259 µg/kg). Animal observation and sampling were performed 1, 3, and 7 days after the exposure. Endogenous creatinine clearance (ECC) decreased in 24 h in the POX2x group (p = 0.011). Glucosuria was observed in rats 24 h after exposure to POX in both M1 and M2 models. After 3 days, an increase in urinary excretion of chondroitin sulfate (CS, p = 0.024) and calbindin (p = 0.006) was observed in rats of the CBPOX group. Morphometric analysis revealed a number of differences most significant for rats in the CBPOX group. Furthermore, there was an increase in the area of the renal corpuscles (p = 0.0006), an increase in the diameter of the lumen of the proximal convoluted tubules (PCT, p = 0.0006), and narrowing of the diameter of the distal tubules (p = 0.001). After 7 days, the diameter of the PCT lumen was still increased in the nephrons of the CBPOX group (p = 0.0009). In the M3 model, histopathological and ultrastructural changes in the kidneys were revealed after the exposure to POX at doses of LD50 and LD84. Over a period from 24 h to 3 days, a significant (p = 0.018) expansion of Bowman’s capsule was observed in the kidneys of rats of both the LD50 and LD84 groups. In the epithelium of the proximal tubules, stretching of the basal labyrinth, pycnotic nuclei, and desquamation of microvilli on the apical surface were revealed. In the epithelium of the distal tubules, partial swelling and destruction of mitochondria and pycnotic nuclei was observed, and nuclei were displaced towards the apical surface of cells. After 7 days of the exposure to POX, an increase in the thickness of the glomerular basement membrane (GBM) was observed in the LD50 and LD84 groups (p = 0.019 and 0.026, respectively). Moreover, signs of damage to tubular epithelial cells persisted with blockage of the tubule lumen by cellular detritus and local destruction of the surface of apical cells. Comparison of results from the three models demonstrates that the nephrotoxic effects of POX, evaluated at 1 and 3 days, appear regardless of prior inhibition of carboxylesterase activity

Fe3+/Fetot ratio in the mantle: A micro-M\uf6ssbauer study of chromites included in diamond and kimberlites

Congresso Associazione Internazionale di Mineralogia, Budapest 21-27 agosto 201