1,083 research outputs found

    The structure of Atlantic Water at Eurasian continental slope in summer 2007

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    Intensive field campaigns during the IPY (2007-2009) allowed unprecedented coverage of Eurasian continental slope by CTD measurements. These data allowed detailed mapping of the warm Atlantic water on its way from Fram Strait to the East Siberian Sea. Fourteen cross-slope sections, carried out by Russian, US and German scientists in August-September 2007 were used to determine position and properties of the warm Atlantic water core. Temperature and salinity data were examined against traditional concept of warm intermediate layer in the Arctic Ocean and in the view of recently introduced new ideas (e.g. seasonal oscillations in AW layer far from Fram Strait). Joined analysis of CTD data with long-term mooring observations demonstrated complex nature of warming-cooling pulses, which enter Arctic Ocean through Fram Strait and effect thermal conditions in Eurasian sector of the Arctic Ocean

    Toward a warmer Arctic Ocean: Spreading of the early 21st century Atlantic Water warm anomaly along the Eurasian Basin margins

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    We document through the analysis of 2002–2005 observational data the recent Atlantic Water (AW) warming along the Siberian continental margin due to several AW warm impulses that penetrated into the Arctic Ocean through Fram Strait in 1999–2000. The AW temperature record from our long-term monitoring site in the northern Laptev Sea shows several events of rapid AW temperature increase totaling 0.8°C in February–August 2004. We hypothesize the along-margin spreading of this warmer anomaly has disrupted the downstream thermal equilibrium of the late 1990s to earlier 2000s. The anomaly mean velocity of 2.4–2.5 ± 0.2 cm/s was obtained on the basis of travel time required between the northern Laptev Sea and two anomaly fronts delineated over the Eurasian flank of the Lomonosov Ridge by comparing the 2005 snapshot along-margin data with the AW pre-1990 mean. The magnitude of delineated anomalies exceeds the level of pre-1990 mean along-margin cooling and rises above the level of noise attributed to shifting of the AW jet across the basin margins. The anomaly mean velocity estimation is confirmed by comparing mooring-derived AW temperature time series from 2002 to 2005 with the downstream along-margin AW temperature distribution from 2005. Our mooring current meter data corroborate these estimations

    Technique and Technology of Whole-Body Cryotherapy (WBC)

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    Whole-body cryotherapy (WBC) is a highly effective treatment method of a number of serious diseases. The therapeutic effect of WBC is achieved by stimulating cold receptors of the patient’s skin, which provide supercooling of the skin surface to the level of −2°C. To achieve such a temperature of the skin surface, it is necessary to ensure heat removal with intensity not less than 3500 W/m2. Such a heat flux can remove gas with the temperature not higher than −130°C. Procedures lasting less than 2 minutes do not form therapeutic effect. Procedures lasting more than 3 minutes are dangerous for the patient’s health. WBC procedures are carried out in single- and multi-seat devices. Due to the compact placement of the patient in the WBC area, the share of useful heat load on the cryostatting system is up to 70%. In multi-seat installations, the useful heat load share is not more than 50%. During the WBC procedure, consumption of liquid nitrogen per patient is 3.77 kg. For the effective use of WBC technology, it is necessary to determine the general requirements for the power of cooling systems and the temperature of cryostatting of the WBC area

    Mathematical model of a flexible asymmetrical rotor for active magnetic bearing reaction wheel

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    The paper introduces the mathematical model of rotor for active magnetic bearing reaction/momentum wheels, used as actuator in spacecraft attitude and orbit control system. Developed model is used for estimation of critical speeds and forced oscillation magnitudes with a glance of the rotor modes. Rotor is considered as a two-mass system, consisting of a shaft and a rim, active magnetic bearings are assumed to be a linear elastic springs. The equations of the rotor motion are derived using the Lagrange equation. Developed model is verified by comparing the calculated Campbell diagrams with the results of the finite-element modal analysis, performed in the ANSYS software

    The two-dimensional electron gas of the In2O3 surface: Enhanced thermopower, electrical transport properties, and its reduction by adsorbates or compensating acceptor doping

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    In2O3 is an n-type transparent semiconducting oxide possessing a surface electron accumulation layer (SEAL) like several other relevant semiconductors, such as InAs, InN, SnO2, and ZnO. Even though the SEAL is within the core of the application of In2O3 in conductometric gas sensors, a consistent set of transport properties of this two-dimensional electron gas (2DEG) is missing in the present literature. To this end, we investigate high quality single-crystalline as well as textured doped and undoped In2O3(111) films grown by plasma-assisted molecular beam epitaxy to extract transport properties of the SEAL by means of Hall effect measurements at room temperature while controlling the oxygen adsorbate coverage via illumination. The resulting sheet electron concentration and mobility of the SEAL are 1.5E13 cm^-2 and 150 cm^2/Vs, respectively, both of which get strongly reduced by oxygen-related surface adsorbates from the ambient air. Our transport measurements further demonstrate a systematic reduction of the SEAL by doping In2O3 with the deep compensating bulk acceptors Ni or Mg. This finding is supported by X-ray photoelectron spectroscopy measurements of the surface band bending and SEAL electron emission. Quantitative analyses of these XPS results using self-consistent, coupled Schroedinger-Poisson calculations indicate the simultaneous formation of compensating bulk donor defects (likely oxygen vacancies) which almost completely compensate the bulk acceptors. Finally, an enhancement of the thermopower by reduced dimensionality is demonstrated in In2O3: Seebeck coefficient measurements of the surface 2DEG with partially reduced sheet electron concentrations between 3E12 and 7E12 cm^-2 (corresponding average volume electron concentration between 1E19 and 2E19 cm^-3 indicate a value enhanced by 80% compared to that of bulk Sn-doped In2O3 with comparable volume electron concentration.Comment: Main article: 11 pages, 7 figures Supplement: 4 pages, 2 figures To be submitted in Physical Review

    Eastern Arctic Ocean Diapycnal Heat Fluxes through Large Double-Diffusive Steps

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    The diffusive layering (DL) form of double-diffusive convection cools the Atlantic Water (AW) as it circulates around the Arctic Ocean. Large DL steps, with heights of homogeneous layers often greater than 10 m, have been found above the AW core in the Eurasian Basin (EB) of the eastern Arctic. Within these DL staircases, heat and salt fluxes are determined by the mechanisms for vertical transport through the high-gradient regions (HGRs) between the homogeneous layers. These HGRs can be thick (up to 5 m and more) and are frequently complex, being composed of multiple small steps or continuous stratification. Microstructure data collected in the EB in 2007 and 2008 are used to estimate heat fluxes through large steps in three ways: using the measured dissipation rate in the large homogeneous layers; utilizing empirical flux laws based on the density ratio and temperature step across HGRs after scaling to account for the presence of multiple small DL interfaces within each HGR; and averaging estimates of heat fluxes computed separately for individual small interfaces (as laminar conductive fluxes), small convective layers (via dissipation rates within small DL layers), and turbulent patches (using dissipation rate and buoyancy) within each HGR. Diapycnal heat fluxes through HGRs evaluated by each method agree with each other and range from ~2 to ~8 W m−2, with an average flux of ~3–4 W m−2. These large fluxes confirm a critical role for the DL instability in cooling and thickening the AW layer as it circulates around the eastern Arctic Ocean

    Text Processing and Cognitive Technologies

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    ABSTRACT This paper presents a study of possible factors that influence lexicalization of motion in Russian, specifically the choice of a verb from pairs of verbs of motion идти-ходить [ . We restricted the study to cases where a narrator observes the scene of motion s/he describes rather than memorizes or imagines it. The conclusion that at least five factors may influence the verb choice is based on the extracts from literature, and empirical observations. The conditions are defined as follows: motion path, motion space, motion regularity, and targeted vs. random motion. The influence of two factors (motion path and motion target) was tested experimentally, and the results have shown that these two factors represent significant determinants of the verb choice
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