100 research outputs found

    Experience in feeding coal into a liquefaction process development unit

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    A system for preparing coal slurry and feeding it into a high pressure liquefaction plant is described. The system was developed to provide supporting research and development for the Bureau of Mines coal liquefaction pilot plant. Operating experiences are included

    Bi2Te3Bi_2Te_3: Implications of the rhombohedral k-space texture on the evaluation of the in-plane/out-of-plane conductivity anisotropy

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    Different computational scheme for calculating surface integrals in anisotropic Brillouin zones are compared. The example of the transport distribution function (plasma frequency) of the thermoelectric Material \BiTe near the band edges will be discussed. The layered structure of the material together with the rhombohedral symmetry causes a strong anisotropy of the transport distribution function for the directions in the basal (in-plane) and perpendicular to the basal plane (out-of-plane). It is shown that a thorough reciprocal space integration is necessary to reproduce the in-plane/out-of-plane anisotropy. A quantitative comparison can be made at the band edges, where the transport anisotropy is given in terms of the anisotropic mass tensor.Comment: 7 pages, 6 figs., subm. to J. Phys. Cond. Ma

    Implementation of a non-equilibrium Green's function method to calculate spin transfer torque

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    We present an implementation of the steady state Keldysh approach in a Green's function multiple scattering scheme to calculate the non-equilibrium spin density. This density is used to obtain the spin transfer torque in junctions showing the magnetoresistance effect. We use our implementation to study the spin transfer torque in metallic Co/Cu/Co junctions.Comment: 4 pages, 4 figure

    Antimicrobial Resistance: A Risk Factor for the Biosafety System

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    Scientific relevance. In recent years, antimicrobial resistance in pathogenic microorganisms has become a global problem that threatens the health of humans and animals and poses a risk to the biosafety of Russia.Aim. The study aimed to analyse the prevalence of antimicrobial resistance, consider the risks and medical consequences of this biological phenomenon, and suggest ways to optimise the use of existing antimicrobial agents and search for new ones.Discussion. The emergence of antibiotic resistance in bacteria is a natural biological process; the selection of resistant microorganisms occurs constantly with the use of the entire spectrum of antimicrobial agents in healthcare, agriculture, and other fields. The World Health Organisation (WHO) monitors these processes using the Global Antimicrobial Resistance Surveillance System (GLASS). Russia has adopted the Strategy to prevent the spread of antimicrobial resistance in the Russian Federation to 2030. The country has established a regulatory framework that supports the operation of the national antimicrobial resistance prevention system. The strategy to prevent the spread of antimicrobial resistance is being implemented through making organisational arrangements and developing novel medicines with mechanisms of action based on an understanding of the molecular mechanisms of infection and resistance. This review considers the main approaches to designing exploratory studies and evaluating the antimicrobial activity of the innovative molecules obtained. The rapid development of synthetic biology increases the likelihood of creating synthetic biological pathogens with high virulence and resistance to antimicrobial agents, which might pose risks of artificial epidemics.Conclusions. The antimicrobial resistance prevention system in Russia should be considered a strategically essential medical technology ensuring the biosafety of the country and the people

    Lorenz function of Bi2_{2}Te3_{3}/Sb2_{2}Te3_{3} superlattices

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    Combining first principles density functional theory and semi-classical Boltzmann transport, the anisotropic Lorenz function was studied for thermoelectric Bi2_{2}Te3_{3}/Sb2_{2}Te3_{3} superlattices and their bulk constituents. It was found that already for the bulk materials Bi2_{2}Te3_{3} and Sb2_{2}Te3_{3}, the Lorenz function is not a pellucid function on charge carrier concentration and temperature. For electron-doped Bi2_{2}Te3_{3}/Sb2_{2}Te3_{3} superlattices large oscillatory deviations for the Lorenz function from the metallic limit were found even at high charge carrier concentrations. The latter can be referred to quantum well effects, which occur at distinct superlattice periods

    Thermoelectric transport in Bi2Te3/Sb2Te3\text{Bi}_2\text{Te}_3/\text{Sb}_2\text{Te}_3 superlattices

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    The thermoelectric transport properties of Bi2Te3/Sb2Te3\text{Bi}_2\text{Te}_3/\text{Sb}_2\text{Te}_3superlattices are analyzed on the basis of first-principles calculations and semi-classical Boltzmann theory. The anisotropy of the thermoelectric transport under electron and hole-doping was studied in detail for different superlattice periods at changing temperature and charge carrier concentrations. A clear preference for thermoelectric transport under hole-doping, as well as for the in-plane transport direction was found for all superlattice periods. At hole-doping the electrical transport anisotropies remain bulk-like for all investigated systems, while under electron-doping quantum confinement leads to strong suppression of the cross-plane thermoelectric transport at several superlattice periods. In addition, insights on the Lorenz function, the electronic contribution to the thermal conductivity and the resulting figure of merit are given
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