44,556 research outputs found

    Flight telerobotic servicer control from the Orbiter

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    The research and work conducted on the development of a testbed for a display and control panel for the Flight Telerobotic Servicer (FTS) are presented. Research was conducted on both software and hardware needed to control the FTS. A breadboard was constructed and placed into a mockup of the aft station of the Orbiter spacecraft. This breadboard concept was then evaluated using a computer graphics representation of the Tinman FTS. Extensive research was conducted on the software requirements and implementation. The hardware selected for the breadboard was 'flight like' and in some cases fit and function evaluated. The breadboard team studied some of the concepts without pursuing in depth their impact on the Orbiter or other missions. Assumptions are made concerning payload integration

    ROSAT observations of the dwarf starforming galaxy Holmerg II (UGC 4305)

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    We present ROSAT PSPC and HRI observations of the dwarf irregular galaxy Holmberg II (UGC4305). This is one of the most luminous dwarf galaxies (Lx~ 10^{40} erg s^{-1} cm^{-2}) detected in the ROSAT All-Sky Survey. The X-ray emission comes from a single unresolved point source, coincident with a large HII region which emits intense radio emission. The source is variable on both year and day timescales, clearly favouring accretion into a compact object rather than a supernova remnant or a superbubble interpretation for the origin of the X-ray emission. However, its X-ray spectrum is well-fit by a a Raymond-Smith spectrum with kT~0.8 keV, lower than the temperature of X-ray binaries in nearby spiral galaxies.Comment: Accepted for publication in MNRA

    Torsion pendulum measurements on viscoelastic materials during vacuum exposure

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    A torsional pendulum apparatus designed for testing in situ in vacuum, the dynamic mechanical properties of materials is described. The application of this apparatus to an experimental program to measure the effects of vacuum on the mechanical properties of two ablator materials (a foamed material and a filled elastomer) and a solid rocket propellant (a filled elastomer) is presented. Results from the program are discussed as to the effects of vacuum on the mechanical properties of these three materials. In addition, time-temperature-superposition, as a technique for accelerating vacuum induced changes in mechanical properties, is discussed with reference to the three materials tested in the subject program

    From 2D Integrable Systems to Self-Dual Gravity

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    We explain how to construct solutions to the self-dual Einstein vacuum equations from solutions of various two-dimensional integrable systems by exploiting the fact that the Lax formulations of both systems can be embedded in that of the self-dual Yang--Mills equations. We illustrate this by constructing explicit self-dual vacuum metrics on R2Ă—ÎŁ\R^2\times \Sigma, where ÎŁ\Sigma is a homogeneous space for a real subgroup of SL(2, \C) associated with the two-dimensional system.Comment: 9 pages, LaTex, no figure

    Extent and Characteristics of Retail Fresh Beef Branding

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    Limited information exists regarding the extent and characteristics of branded fresh beef. Retail package data from a sample of grocery stores in three metropolitan areas enabled determining the extent of branded beef for ground beef, roasts, and steaks. Logit models identified factors affecting the probability of beef products being branded, and the probability of beef products carrying specific types of brands compared with store brands and generic (unbranded) beef. The extent of branded beef and type of brand both varied by store type, specific product, quality designation, package type, and presence of special labeling.Marketing,
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