36,013 research outputs found

    Evaluation of a hemispherical head flow direction sensor for inlet duct measurements

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    A hemispherical head flow direction sensor was tested in a wind tunnel to evaluate its effectiveness for measuring dynamic duct flow direction angles of plus and minus 27 degrees. The tests were conducted at Reynolds numbers of 3.8 million per meter (1.0 million per foot) and 4.92 million per meter (1.5 million per foot) and at Mach numbers from 0.30 to 0.70. The design criteria for the probe are discussed and the wind tunnel results are presented. Three techniques for deriving the flow angles are described

    The Initial Value Problem For Maximally Non-Local Actions

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    We study the initial value problem for actions which contain non-trivial functions of integrals of local functions of the dynamical variable. In contrast to many other non-local actions, the classical solution set of these systems is at most discretely enlarged, and may even be restricted, with respect to that of a local theory. We show that the solutions are those of a local theory whose (spacetime constant) parameters vary with the initial value data according to algebraic equations. The various roots of these algebraic equations can be plausibly interpreted in quantum mechanics as different components of a multi-component wave function. It is also possible that the consistency of these algebraic equations imposes constraints upon the initial value data which appear miraculous from the context of a local theory.Comment: 8 pages, LaTeX 2 epsilo

    Limits on the Halo White Dwarf Component of Baryonic Dark Matter from the {\em Hubble Deep Field}

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    The MACHO collaboration lensing event statistics suggest that a significant fraction of the dark galactic halo can be comprised of baryonic matter in the form of white dwarf stars with masses between 0.1 and 1.0 \Msun . Such a halo white dwarf population, in order to have escaped detection by those who observe the white dwarf luminosity function of the disk, must have formed from an old population. The observations indicate that the number of halo white dwarfs per cubic parsec per unit bolometric magnitude is less than 10510^{-5} at 104.510^{-4.5}\Lsun; the number must rise significantly at lower luminosities to provide the needed baryonic halo mass. Such white dwarfs may easily escape detection in most current and earlier surveys. Though it is limited in angular extent, the {\em Hubble Deep Field} (HDF) probes a sufficient volume of the galactic halo to provide interesting limits on the number of halo white dwarf stars, and on the fraction of the halo mass that they can make up. If the HDF field can be probed for stars down to V=29.8V=29.8 then the MACHO result suggests that there could be up to 12 faint halo white dwarfs visible in the HDF. Finding (or not finding) these stars in turn places interesting constraints on star formation immediately following the formation of the galaxy.Comment: 10 pages, AASTEX, 1 table, no figures, accepted for publication in Ap.J. Letter

    A comparative analysis of the decoupling effects in a magnetic forming beryllium coil assembly

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    Digital computer for determining currents and forces in magnetic forming beryllium coil assembl

    Implementation of the Multiple Point Principle in the Two-Higgs Doublet Model of type II

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    The multiple point principle (MPP) is applied to the non--supersymmetric two-Higgs doublet extension of the Standard Model (SM). The existence of a large set of degenerate vacua at some high energy scale caused by the MPP results in a few relations between Higgs self-coupling constants which can be examined at future colliders. The numerical analysis reveals that these MPP conditions constrain the mass of the SM--like Higgs boson to lie below 180 GeV for a wide set of MPP scales Λ\Lambda and tanβ\tan\beta.Comment: 26 pages, 3 figures, some minor changes to the tex
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