27,474 research outputs found

    Studies of magnetostriction and spin polarized band structures of rare earth intermetallics

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    Anisotropic magnetostriction measurements of R6Fe23, R = (Tb, Dy, Ho, and Er) were carried out from 77 K to room temperature. Magnetic fields up to 2.1 Tesla were applied. All the compounds exhibited large magnetostrictions at 77 K, the largest effect being obtained for Tb6Fe23. Saturation magnetostriction values for the compounds were also determined for 77 K and room temperature. Results of the temperature dependence of magnetostriction for Er6Fe23 are in good agreement with Callen and Callen's single ion theory. Therefore, the main sources of magnetostriction in this compound is the Er ion. The spin-up and spin-down electronic energy bands, the density of states and the magnetic moments of YCo5, SmCo5, and GdCo5 were calculated by the spin polarized augmented plane wave technique. The calculations obtained show the origin of the moment, provide good estimates of its magnitude and variation, and the reasons for those variations. They also show the important role of partial charge transfer and of d-d electronic coupling. Calculations for LaNi5 and GdNi5 systems are discussed

    Machine Science in Biomedicine: Practicalities, Pitfalls and Potential

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    Machine Science, or Data-driven Research, is a new and interesting scientific methodology that uses advanced computational techniques to identify, retrieve, classify and analyse data in order to generate hypotheses and develop models. In this paper we describe three recent biomedical Machine Science studies, and use these to assess the current state of the art with specific emphasis on data mining, data assessment, costs, limitations, skills and tool support

    Data report of six free-drifting buoys tracked by the Eole satellite in the western North Atlantic Ocean in the autumn of 1972

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    The buoys were deployed on the Continental Shelf east of the Chesapeake Light and were tracked by the French EOLE satellite. Two buoys drifted for 11 days during the first mission and four buoys drifted for 14 days during the second mission. Trajectory and water temperature data are presented in tabular and graphical from with a discussion of the accuracy

    Pre-emphasis determination for an S-band constant bandwidth FM/FM station

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    Telemetry bands are being reassigned to UHF at 1500 and 2200 MHz. Conversion primarily requires changes in equipment used in RF link, while many of same subcarrier oscillators, mixer amplifiers, and frequency discriminators can be used

    Data report of four free-drifting buoys tracked by the Eole satellite in the western North Atlantic Ocean in the winter of 1973

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    Data from four free-drifting buoys deployed near Chesapeake Light on February 20, 1973 is presented. Position and water temperature data are presented in tabular and graphic form

    Mercury in the environment

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    Problems in assessing mercury concentrations in environmental materials are discussed. Data for situations involving air, water, rocks, soils, sediments, sludges, fossil fuels, plants, animals, foods, and man are drawn together and briefly evaluated. Details are provided regarding the toxicity of mercury along with tentative standards and guidelines for mercury in air, drinking water, and food

    Optimal Fleet Size When National Quotas Can Be Traded

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    Assuming stochastic quotas for a fish stock that is shared between two nations, we find the optimal fleet size for one of them by maximizing expected profit under the assumption that national quotas can be traded and that stable national quotas is a political goal. As an example we use the Norwegian purse seiner fleet and the summer capelin fishery in the Barents Sea.Environmental Economics and Policy, International Development, International Relations/Trade, Resource /Energy Economics and Policy,

    Molecular astronomy of cool stars and sub-stellar objects

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    The optical and infrared spectra of a wide variety of `cool' astronomical objects including the Sun, sunspots, K-, M- and S-type stars, carbon stars, brown dwarfs and extrasolar planets are reviewed. The review provides the necessary astronomical background for chemical physicists to understand and appreciate the unique molecular environments found in astronomy. The calculation of molecular opacities needed to simulate the observed spectral energy distributions is discussed
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