9,873 research outputs found

    Walking the Talk: A Guide to Assessment Using the CAPRA Community Problem Solving Model

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    CAPRA is a community problem-solving model with five stages: C = Clients, A = Analysis, P = Partnership, R = Response, and A = Assessment. CAPRA was the problem-solving method used by the Alaska Native and Technical Resource Center (ANTARC). This guide describes the final stage of the CAPRA model—assessment—including the reasons for conducing an assessment, the documentation needed and why it is needed, and methods for evaluation. Discussion is with a particular focus on assessment methods for community problem-solvers in rural Alaska Native villages. Some background about CAPRA is assumed.What is Assessment? / Why do we do Assessment? / Assessment = Documentation + Evaluation / Documentation / Evaluation / How Do We Deal With those Who Object to Assessment? / What DO We Do With Our Assessment? / Conclusio

    Instability analysis procedure for 3-level multi-bearing rotor-foundation systems

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    A procedure for the instability analysis of a three-level multispan rotor systems is described. This procedure is based on a distributed mass elastic representation of the rotor system in several eight-coefficient bearings. Each bearing is supported from an elastic foundation on damped, elastic pedestals. The foundation is represented as a general distributed mass elastic structure on discrete supports, which may have different stiffness and damping properties in the horizontal and vertical directions. This system model is suited to studies of instability threshold conditions for multirotor turbomachines on either massive or flexible foundations. The instability conditions is found by obtaining the eigenvalues of the system determinant, which is obtained by the transfer matrix method from the three-level system model. The stability determinant is solved for the lowest rotational speed at which the system damping becomes zero in the complex eigenvalue, and for the whirl frequency corresponding to the natural frequency of the unstable mode. An efficient algorithm for achieving this is described. Application of this procedure to a rigid rotor in two damped-elastic bearings and flexible supports is described. A second example discusses a flexible rotor with four damped-elastic bearings. The third case compares the stability of a six-bearing 300 Mw turbine generator unit, using two different bearing types. These applications validate the computer program and various aspects of the analysis

    Alaska Native Technical Assistance and Resource Center: Final Report

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    Too often, federal and state justice programs directed at rural, predominately Alaska Native villages do not sufficiently coordinate planning and funding, and are not tailored to fit local cultures and needs. The language and institutional contexts of granting agencies and requests for proposals for grants frame justice problems and their solutions in ways that may or may not relate to the experiences of Alaska Native villages. The Alaska Native Technical Resource Center (ANTARC) was designed as a three-year project to improve village capacity to identify problems and educate the university and granting agencies about the nature of their justice problems and the resources needed to implement solutions. The initial group involved the Justice Center and four rural communities — Gulkana, Kotlik, Wainwright, and Yakutat — with representatives from the communities chosen by village leaders. This report examines ANTARC's evolution, considers its implementation, evaluates the results, and presents recommendations for promoting effective change in Alaska Native villages.Bureau of Justice Assistance, United States Department of Justice Award No. 1999-LB-VX-002Introduction / The Evolution of Antarc / Structure of the Project / Implementation / Evaluating Results / Concluding Recommendations / References / Appendix 1: Proceedings of the March 1999 Antarc Workshop / Appendix 2: Proceedings of the November 1999 Antarc Workshop / Appendix 3: Capra Training Materials / Appendix 4: Evaluation Training Workshop Material

    Domain Growth in Random Magnets

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    We study the kinetics of domain growth in ferromagnets with random exchange interactions. We present detailed Monte Carlo results for the nonconserved random-bond Ising model, which are consistent with power-law growth with a variable exponent. These results are interpreted in the context of disorder barriers with a logarithmic dependence on the domain size. Further, we clarify the implications of logarithmic barriers for both nonconserved and conserved domain growth.Comment: 7 pages, 4 figure

    Bifurcation analysis in an associative memory model

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    We previously reported the chaos induced by the frustration of interaction in a non-monotonic sequential associative memory model, and showed the chaotic behaviors at absolute zero. We have now analyzed bifurcation in a stochastic system, namely a finite-temperature model of the non-monotonic sequential associative memory model. We derived order-parameter equations from the stochastic microscopic equations. Two-parameter bifurcation diagrams obtained from those equations show the coexistence of attractors, which do not appear at absolute zero, and the disappearance of chaos due to the temperature effect.Comment: 19 page

    First results of the CERN Resonant WISP Search (CROWS)

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    The CERN Resonant WISP Search (CROWS) probes the existence of Weakly Interacting Sub-eV Particles (WISPs) like axions or hidden sector photons. It is based on the principle of an optical light shining through the wall experiment, adapted to microwaves. Critical aspects of the experiment are electromagnetic shielding, design and operation of low loss cavity resonators and the detection of weak sinusoidal microwave signals. Lower bounds were set on the coupling constant g=4.5⋅10−8g = 4.5 \cdot 10^{-8} GeV−1^{-1} for axion like particles with a mass of ma=7.2μm_a = 7.2 \mueV. For hidden sector photons, lower bounds were set for the coupling constant χ=4.1⋅10−9\chi = 4.1 \cdot 10^{-9} at a mass of mγ′=10.8μm_{\gamma'} = 10.8 \mueV. For the latter we were probing a previously unexplored region in the parameter space

    Chaos in the Random Field Ising Model

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    The sensitivity of the random field Ising model to small random perturbations of the quenched disorder is studied via exact ground states obtained with a maximum-flow algorithm. In one and two space dimensions we find a mild form of chaos, meaning that the overlap of the old, unperturbed ground state and the new one is smaller than one, but extensive. In three dimensions the rearrangements are marginal (concentrated in the well defined domain walls). Implications for finite temperature variations and experiments are discussed.Comment: 4 pages RevTeX, 6 eps-figures include

    A future very-high-energy view of our Galaxy

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    The survey of the inner Galaxy with H.E.S.S. was remarkably successful in detecting a wide range of new very-high-energy gamma-ray sources. New TeV gamma-ray emitting source classes were established, although several of the sources remain unidentified, and progress has been made in understanding particle acceleration in astrophysical sources. In this work, we constructed a model of a population of such very-high-energy gamma-ray emitters and normalised the flux and size distribution of this population model to the H.E.S.S.-discovered sources. Extrapolating that population of objects to lower flux levels we investigate what a future array of imaging atmospheric telescopes (IACTs) such as AGIS or CTA might detect in a survey of the Inner Galaxy with an order of magnitude improvement in sensitivity. The sheer number of sources detected together with the improved resolving power will likely result in a huge improvement in our understanding of the populations of galactic gamma-ray sources. A deep survey of the inner Milky Way would also support studies of the interstellar diffuse gamma-ray emission in regions of high cosmic-ray density. In the final section of this paper we investigate the science potential for the Galactic Centre region for studying energy-dependent diffusion with such a future array.Comment: Proceeding of "Heidelberg International Symposium on High Energy Gamma-Ray Astronomy", held in Heidelberg, 7-11 July 2008, submitted to AIP Conference Proceedings. 4 pages, 4 figure

    VERITAS Observations of the Coma Cluster of Galaxies

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    Clusters of galaxies are one of the few prominent classes of objects predicted to emit gamma rays not yet detected by satellites like EGRET or ground-based Imaging Atmospheric Cherenkov Telescopes (IACTs). The detection of Very High Energy (VHE, E > 100 GeV) gamma rays from galaxy clusters would provide insight into the morphology of non-thermal particles and fields in clusters. VERITAS, an array of four 12-meter diameter IACTs, is ideally situated to observe the massive Coma cluster, one of the best cluster candidates in the Northern Hemisphere. This contribution details the results of VERITAS observations of the Coma cluster of galaxies during the 2007-2008 observing season.Comment: Submitted to Proceedings of "4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy 2008
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