11,577 research outputs found

    Integration of ground and on-board system for terminal count

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    The development of an integrated ground and onboard system for Space Shuttle terminal count management is discussed. The criteria considered in designing this system are outlined. Examples of problems encountered in the process of maturing the design are presented

    Universal dissipation scaling for non-equilibrium turbulence

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    It is experimentally shown that the non-classical high Reynolds number energy dissipation behaviour, CÏ”â‰ĄÏ”L/u3=f(ReM)/ReLC_{\epsilon} \equiv \epsilon L/u^3 = f(Re_M)/Re_L, observed during the decay of fractal square grid-generated turbulence is also manifested in decaying turbulence originating from various regular grids. For sufficiently high values of the global Reynolds numbers ReMRe_M, f(ReM)∌ReMf(Re_M)\sim Re_M.Comment: 5 pages, 6 figure

    Photochemical colour change for traditional watercolour pigments in low oxygen levels

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    An investigation for light exposure on pigments in low-oxygen environments (in the range 0–5% oxygen) was conducted using a purpose-built automated microfadometer for a large sample set including multiple samples of traditional watercolour pigments from nineteenth-century and twentieth-century sources, selected for concerns over their stability in anoxia. The pigments were prepared for usage in watercolour painting: ground and mixed in gum Arabic and applied to historically accurate gelatine glue-sized cotton and linen-based papers. Anoxia benefited many colorants and no colorant fared worse in anoxia than in air, with the exception of Prussian blue and Prussian green (which contains Prussian blue). A Prussian blue sampled from the studio materials of J.M.W. Turner (1775 − 1851) was microfaded in different environments (normal air (20.9% oxygen) 0, 1, 2, 3.5, or 5% oxygen in nitrogen) and the subsequent dark behaviour was measured. The behaviour of the sample (in normal air, anoxia, and 5% oxygen in nitrogen) proved to be consistent with the 55 separately sourced Prussian blue samples. When exposed to light in 5% oxygen in nitrogen, Prussian blue demonstrated the same light stability as in air (at approximately 21°C and 1 atmosphere). Storage in 5% oxygen is proposed for ‘anoxic’ display of paper-based artworks that might contain Prussian blue, to protect this material while reducing light-induced damage to other components of a watercolour, including organic colorants and the paper support

    Superconformal mechanics, black holes, and non-linear realizations

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    The OSp(2|2)-invariant planar dynamics of a D=4 superparticle near the horizon of a large mass extreme black hole is described by an N=2 superconformal mechanics, with the SO(2) charge being the superparticle's angular momentum. The {\it non-manifest} superconformal invariance of the superpotential term is shown to lead to a shift in the SO(2) charge by the value of its coefficient, which we identify as the orbital angular momentum. The full SU(1,1|2)-invariant dynamics is found from an extension to N=4 superconformal mechanics.Comment: 19 pages, plain latex file. Slightly shortened version, two references adde

    ‘But by blood no wolf am I’: Language and Agency, Instinct and Essence – Transcending Antinomies in Maggie Stiefvater’s Shiver trilogy

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    Young Adult dark romance is often more questioning than its adult counterpart; different, less constraining commercial imperatives are perhaps at work, or readers’ expectations less fixed. This chapter will show how, woven into a sensitive coming-of-age narrative of first love and familial problems, Maggie Stiefvater’s Shiver trilogy performs a far more sophisticated interrogation of the boundaries of animality and humanity than other such fictions, highlighting the centrality of language and its relationship to agency. The hero, Sam’s, struggle with his lupine nature becomes an existentialist refusal to be defined by nature; other characters are tempted instead to yield to a fatalistic surrender of will. The books are tantalisingly ambivalent about the appeal of the instinctual and the borderline between an embodied humanity and the animal, particularly as manifested in the love affair of the teenage protagonists. For Marcuse, the surplus-repression of the proximity senses (smell, taste) enforces the isolation of individuals in civilisation. Stiefvater continually emphasises the sense of smell both as a trigger to sexual attraction and as an aspect of the pack sociality and sense of belonging of the wolves. Through such devices, she concretely renders the nearness of Grace and Sam (her young lovers) to wolfhood. This is contrasted with her exploration of human subjectivity through language, particularly in the perceptive depiction of silences and miscommunications and her hero’s absorption in books and poetry

    Quantum cryptography with squeezed states

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    A quantum key distribution scheme based on the use of displaced squeezed vacuum states is presented. The states are squeezed in one of two field quadrature components, and the value of the squeezed component is used to encode a character from an alphabet. The uncertainty relation between quadrature components prevents an eavesdropper from determining both with enough precision to determine the character being sent. Losses degrade the performance of this scheme, but it is possible to use phase-sensitive amplifiers to boost the signal and partially compensate for their effect.Comment: 15 pages, no figure

    Manejo de pastagem.

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    Este folder apresenta informaçÔes båsicas sobre manejo de pastagem: o objetivo do manejo de pastagem; sistemas de pastejo; taxa de lotação; pressão do pastejo, capacidade de suportebitstream/CPAF-RO-2010/14520/1/folder-pastagem.pdfFolder
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