875 research outputs found

    Characterization of central elements of operator algebras by inequalities

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    We propose a list of inequalities which characterize central elements in von Neumann algebras and C*-algebras

    MIXING VISCOUS LIQUIDS IN SETTLING TANKS

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    The study adresses the problem of maintaining the operability of settling tanks designed for storing contaminated liquids. The study provided a method of mixing of bottom sludge and a mathematical model for determining initial velocity of outflow from the flat orifice depending on physical, mechanical and rheological parameters of the bottom sludge

    Atmospheric Aerosol Limb Scanning Based on the Lunar Eclipses Photometry

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    The work is devoted to the analysis of the surface photometric observations of two total lunar eclipses in 2004. The lunar surface relative brightness distribution inside the umbra was used to retrieve the vertical distribution of aerosol extinction of the solar radiation expanding by a tangent path and its dependence on the location at the limb of the Earth. The upper altitude of troposphere aerosol layer was estimated for different latitude zones. The correlation between additional aerosol extinction in the upper troposphere and cyclones was investigated.Comment: 17 pages, 10 figures, submitted to Journal of Quantitative Spectroscopy and Radiative Transfe

    The Enrichment of Stale Tailings of Bom-gorhon Tungsten Ore Deposits

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    The results of mineralogical studies of technogenic tungsten raw material (stale tailings of Bom-Gorhon deposit) are represented. Its particle size distribution as well as tungsten and accompanying element distribution among the fractions were determined. The necessity of grinding the heaps down to 0.2-0.25 mm in size was established. It allows increasing the recovery rate of two or more times in comparison with the traditional pattern of tailing processing

    New behavioral forms of sportsman students identification in university digital educational reality

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    The relevance of the research is due to a wide range of changes in the University educational reality caused by the influence of the Internet, computers, smartphones, mobile devices and modern gadgets on the behavioural forms of student identification. These processes are becoming a matter of particular concern to the public and University teachers. In this regard, this study reveals the features of the value priorities of the University digital educational reality, which modify the behavioural forms of student identification. In the course of pedagogical modelling, which is the leading research method, the phenomenon of new behavioural forms of student identification is identified as the leading idea of the University digital educational reality. This article reveals the key values of student identity identification in the University digital educational reality. The structure and content of new behavioural forms of student identification are established. Based on the research materials, the correction module of new behavioural forms of student identification in the University digital educational reality is justified. The module effectiveness is proved by the results of using new behavioural forms of student identification in the University educational process. The materials of the article are recommended to teachers, methodologists, organizers of the educational process and University students

    Reactive SPS of Al2O3–RE:YAG (RE = Ce; Ce+Gd) composite ceramic phosphors

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    Ultrafine-grained Al2O3–rare earth:yttrium aluminium garnet (Al2O3–RE:YAG) (RE = Ce; Ce+Gd) composite ceramics were obtained for the first time by reactive spark plasma sintering (SPS) using commercially available initial oxide powders. The effect of key sintering parameters (temperature, dwell time, and external pressure (Pload)) on densification peculiarities, structural-phase states, and luminescent properties of composites was studied comprehensively. Differences in phase formation and densification between Ce-doped and Ce,Gd-codoped systems were shown. Parameters of reactive SPS, at which there is partial melting with the formation of near-eutectic zones of the Al2O3–YAG system/coexistence of several variations of the YAG-type phase, were established. Pure corundum–garnet biphasic ceramics with an optimal balance between microstructural and luminescence performance were synthesized at 1425 ℃/30 min/30–60 MPa. The external quantum efficiency (EQE) of the phosphor converters reached 80.7% and 72% with close lifetime of ~63.8 ns, similar to those of commercial Ce:YAG materials, which is promising for further applications in the field of high-power white light-emitting diodes (WLEDs) and laser diodes (LDs)

    Erot spatiaalisissa ja ajallisissa reaktionormeissa kevään ja syksyn fenologisille tapahtumille

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    For species to stay temporally tuned to their environment, they use cues such as the accumulation of degree-days. The relationships between the timing of a phenological event in a population and its environmental cue can be described by a population-level reaction norm. Variation in reaction norms along environmental gradients may either intensify the envi- ronmental effects on timing (cogradient variation) or attenu- ate the effects (countergradient variation). To resolve spatial and seasonal variation in species’ response, we use a unique dataset of 91 taxa and 178 phenological events observed across a network of 472 monitoring sites, spread across the nations of the former Soviet Union. We show that compared to local rates of advancement of phenological events with the advancement of temperature-related cues (i.e., variation within site over years), spatial variation in reaction normsPeer reviewe

    Phenological shifts of abiotic events, producers and consumers across a continent

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    Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe
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