29,091 research outputs found

    Interpretation of AIS Images of Cuprite, Nevada Using Constraints of Spectral Mixtures

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    A technique is outlined that tests the hypothesis Airborne Imaging Spectrometer (AIS) image spectra are produced by mixtures of surface materials. This technique allows separation of AIS images into concentration images of spectral endmembers (e.g., surface materials causing spectral variation). Using a spectral reference library it was possible to uniquely identify these spectral endmembers with respect to the reference library and to calibrate the AIS images

    A low molecular weight hydrogel with unusual gel aging

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    We describe a dipeptide hydrogel with unusual aging characteristics. Over time, a transformation from a turbid gel to a transparent gel occurs which is initiated from the air–water interface. Here, we investigate this transition and discuss the implications of this aging on the bulk properties of the gel

    STAR inner tracking upgrade - A performance study

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    Anisotropic flow measurements have demonstrated development of partonic collectivity in 200GeV200\mathrm{GeV} Au+Au collisions at RHIC. To understand the partonic EOS, thermalization must be addressed. Collective motion of heavy-flavor (c,b) quarks can be used to indicate the degree of thermalization of the light-flavor quarks (u,d,s). Measurement of heavy-flavor quark collectivity requires direct reconstruction of heavy-flavor hadrons in the low \pt region. Measurement of open charm spectra to high \pt can be used to investigate heavy-quark energy loss and medium properties. The Heavy Flavor Tracker (HFT), a proposed upgrade to the STAR experiment at midrapidity, will measure v2v_{2} of open-charm hadrons to very low \pt by reconstructing their displaced decay vertices. The innermost part of the HFT is the PIXEL detector (made of two low mass monolithic active pixel sensor layers), which delivers a high precision position measurement close to the collision vertex. The Intermediate Silicon Tracker (IST), a 1-layer strip detector, is essential to improve hit identification in the PIXEL detector when running at full RHIC-II luminosity. Using a full GEANT simulation, open charm measurement capabilities of STAR with the HFT will be shown. Its performance in a broad \pt range will be demonstrated on v2v_{2} (\pt > 0.5\mathrm{GeV}/c) and RCPR_\mathrm{CP} (\pt < 10\mathrm{GeV}/c) measurements of \D meson. Results of reconstruction of \Lc baryon in heavy-ion collisions are presented.Comment: to appear in EPJ C (Hot Quarks 2008 conference volume

    The finite element machine: An experiment in parallel processing

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    The finite element machine is a prototype computer designed to support parallel solutions to structural analysis problems. The hardware architecture and support software for the machine, initial solution algorithms and test applications, and preliminary results are described

    Hyperspherical Harmonics, Separation of Variables and the Bethe Ansatz

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    The relation between solutions to Helmholtz's equation on the sphere Sn−1S^{n-1} and the [{\gr sl}(2)]^n Gaudin spin chain is clarified. The joint eigenfuctions of the Laplacian and a complete set of commuting second order operators suggested by the RR--matrix approach to integrable systems, based on the loop algebra \wt{sl}(2)_R, are found in terms of homogeneous polynomials in the ambient space. The relation of this method of determining a basis of harmonic functions on Sn−1S^{n-1} to the Bethe ansatz approach to integrable systems is explained.Comment: 14 pgs, Plain Tex, preprint CRM--2174 (May, 1994

    The Mouth Parts of the Firebrat Thermobia domestica (Packard), (Thysanura)

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    The purpose of this paper is to present detailed drawings of the external form of the mouth parts of the adult firebrat, as a representative lepismatid. That the Lepismatidae, or silverfish insects, are of great significance in insect morphology, is well known to students of the subject. In certain respects they are the principle morphological link between the Apterygota and the Pterygota. While any of the widely distributed, domestic species of Lepisma or Ctenolepisma might well be used for morphological study, the firebrat, Thermobia domestica, is the species which seems to us the most likely to be practical for use in experimental biology, largely because it is thermophilic and can be reared comparatively quickly at high constant temperatures (Adams, HJ33, 1936; Sweetman, 1938). This insect has been used successfully in a series of toxicological studies carried on at Iowa State College: one of the more recent of these is an investigation of the toxicity of barium compounds (Richardson and Seiferle, 1941). The morphology of this insect, including the structure of its mouth parts, is likely to be of interest to a considerable variety of workers

    Sweetest Girl In Dixie

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    https://digitalcommons.library.umaine.edu/mmb-vp/6624/thumbnail.jp

    Large perturbation flow field analysis and simulation for supersonic inlets

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    An analysis technique for simulation of supersonic mixed compression inlets with large flow field perturbations is presented. The approach is based upon a quasi-one-dimensional inviscid unsteady formulation which includes engineering models of unstart/restart, bleed, bypass, and geometry effects. Numerical solution of the governing time dependent equations of motion is accomplished through a shock capturing finite difference algorithm, of which five separate approaches are evaluated. Comparison with experimental supersonic wind tunnel data is presented to verify the present approach for a wide range of transient inlet flow conditions

    Large deviations for many Brownian bridges with symmetrised initial-terminal condition

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    Consider a large system of NN Brownian motions in Rd\mathbb{R}^d with some non-degenerate initial measure on some fixed time interval [0,β][0,\beta] with symmetrised initial-terminal condition. That is, for any ii, the terminal location of the ii-th motion is affixed to the initial point of the σ(i)\sigma(i)-th motion, where σ\sigma is a uniformly distributed random permutation of 1,...,N1,...,N. Such systems play an important role in quantum physics in the description of Boson systems at positive temperature 1/β1/\beta. In this paper, we describe the large-N behaviour of the empirical path measure (the mean of the Dirac measures in the NN paths) and of the mean of the normalised occupation measures of the NN motions in terms of large deviations principles. The rate functions are given as variational formulas involving certain entropies and Fenchel-Legendre transforms. Consequences are drawn for asymptotic independence statements and laws of large numbers. In the special case related to quantum physics, our rate function for the occupation measures turns out to be equal to the well-known Donsker-Varadhan rate function for the occupation measures of one motion in the limit of diverging time. This enables us to prove a simple formula for the large-N asymptotic of the symmetrised trace of e−βHN{\rm e}^{-\beta \mathcal{H}_N}, where HN\mathcal{H}_N is an NN-particle Hamilton operator in a trap
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