46,750 research outputs found

    Experiments with Magnetohydrodynamically Supported Shock Layers

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    Shock tube experiments to determine interaction of hypersonic flow with magnetic fiel

    Spin projection and spin current density within relativistic electronic transport calculations

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    A spin projection scheme is presented which allows the decomposition of the electric conductivity into two different spin channels within fully relativistic abab initioinitio transport calculations that account for the impact of spin-orbit coupling. This is demonstrated by calculations of the spin-resolved conductivity of Fe1x_{1-x}Crx_x and Co1x_{1-x}Ptx_x disordered alloys on the basis of the corresponding Kubo-Greenwood equation implemented using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) band structure method. In addition, results for the residual resistivity of diluted Ni-based alloys are presented that are compared to theoretical and experimental ones that rely on Mott's two-current model for spin-polarized systems. The application of the scheme to deal with the spin-orbit induced spin Hall effect is discussed in addition

    Household item ownership and self-rated health: material and psychosocial explanations

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    Background: There has been an ongoing debate whether the effects of socioeconomic factors on health are due to absolute poverty and material factors or to relative deprivation and psychosocial factors. In the present analyses, we examined the importance for health of material factors, which may have a direct effect on health, and of those that may affect health indirectly, through psychosocial mechanisms.Methods: Random national samples of men and women in Hungary (n=973) and Poland (n=1141) were interviewed (response rates 58% and 59%, respectively). The subjects reported their self-rated health, socioeconomic circumstances, including ownership of different household items, and perceived control over life. Household items were categorised as "basic needs", "socially oriented", and "luxury". We examined the association between the ownership of different groups of items and self-rated health. Since the lists of household items were different in Hungary and Poland, we conducted parallel identical analyses of the Hungarian and Polish data.Results: The overall prevalence of poor or very poor health was 13% in Poland and 25% in Hungary. Education, material deprivation and the number of household items were all associated with poor health in bivariate analyses. All three groups of household items were positively related to self-rated health in age-adjusted analyses. The relation of basic needs items to poor health disappeared after controlling for other socioeconomic variables (mainly material deprivation). The relation of socially oriented and luxury items to poor health, however, persisted in multivariate models. The results were similar in both datasets.Conclusions: These data suggest that health is influenced by both material and psychosocial aspects of socioeconomic factors

    The Patent Paradox Revisited: Determinants of Patenting in the US Semiconductor Industry, 1980-94

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    This paper examines the patenting behavior of firms in an industry characterized by rapid technological change and cumulative innovation. Recent evidence suggests that semiconductor firms do not rely heavily on patents, despite the strengthening of US patent rights in the early 1980s. Yet the propensity of semiconductor firms to patent has risen dramatically over the past decade. This paper explores this apparent paradox by analyzing the patenting activities of almost 100 US semiconductor firms during 1980-94. The results suggest that stronger patents may have facilitated entry by firms in niche product markets, while spawning patent portfolio races' among capital-intensive firms.

    Heat transfer measurements in partially ionized gases

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    Heat transfer measurements in partially ionized gase

    One hundred angstrom niobium wire

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    Composite of fine niobium wires in copper is used to study the size and proximity effects of a superconductor in a normal matrix. The niobium rod was drawn to a 100 angstrom diameter wire on a copper tubing

    Heat transfer measurements in partially ionized gases research report no. 196

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    Heat transfer measurements in partially ionized gases - high temperature convective energy transpor

    Flatfish herding behavior in response to trawl sweeps: a comparison of diel responses to conventional sweeps and elevated sweeps

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    Commercial bottom trawls often have sweeps to herd fish into the net. Elevation of the sweeps off the seaf loor may reduce seafloor disturbance, but also reduce herding effectiveness. In both field and laboratory experiments, we examined the behavior of flatfish in response to sweeps. We tested the hypotheses that 1) sweeps are more effective at herding flatfish during the day than at night, when fish are unable to see approaching gear, and that 2) elevation of sweeps off the seafloor reduces herding during the day, but not at night. In sea trials, day catches were greater than night catches for four out of six flatfish species examined. The elevation of sweeps 10 cm significantly decreased catches during the day, but not at night. Laboratory experiments revealed northern rock sole (Lepidopsetta polyxystra) and Pacific halibut (Hippoglossus stenolepis) were more likely to be herded\ud by the sweep in the light, whereas in the dark they tended to pass under or over the sweep. In the light, elevation of the sweep reduced herding, and more fish passed under the sweep. In contrast, in the dark, sweep elevation had little effect upon the number of fish that exhibited herding behavior. The results of both field and laboratory experiments were consistent with the premise that vision is the principle sensory input that controls fish behavior and orientation to trawl gear, and gear performance will differ between conditions where flatfish can see, in contrast to where they cannot see, the approaching gear
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