69,473 research outputs found

    Recent Results on Charmonium Decays at CLEO-c

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    The CLEO-c Experiment has made several recent contributions to the study of charmonium decays. This review briefly outlines the CLEO-c analyses of charmonium that were completed or made public during 2010. Special attention is given to the discovery of the process e+e- to pi+pi-h_c at a center of mass energy of 4170 MeV.Comment: Proceedings for CHARM 201

    PWA of 3pi Final States and a Search for the pi1(1600)

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    Partial wave analyses (PWA) of the 3pi systems in the reactions pi- p --> pi+ pi- pi- p (the ``charged'' mode) and pi- p --> pi- pi0 pi0 p (the ``neutral'' mode) with an 18.3 GeV/c pion beam were performed using high statistics data from the E852 experiment. Conventional signals, such as the a1(1260), the a2(1320), and the pi2(1670), were found to be remarkably stable to the choice of waves included in the fit. In contrast, possible evidence for the pi1(1600) in the JPC = 1-+ exotic wave amplitude disappears when additional decay modes of conventional mesons (especially those of the pi2(1670)) are included in the PWA fit.Comment: Hadron05 Proceedings, 5 pages, 4 figure

    NASA's Advanced solid rocket motor

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    The Advanced Solid Rocket Motor (ASRM) will not only bring increased safety, reliability and performance for the Space Shuttle Booster, it will enhance overall Shuttle safety by effectively eliminating 174 failure points in the Space Shuttle Main Engine throttling system and by reducing the exposure time to aborts due to main engine loss or shutdown. In some missions, the vulnerability time to Return-to-Launch Site aborts is halved. The ASRM uses case joints which will close or remain static under the effects of motor ignition and pressurization. The case itself is constructed of the weldable steel alloy HP 9-4-0.30, having very high strength and with superior fracture toughness and stress corrosion resistance. The internal insulation is strip-wound and is free of asbestos. The nozzle employs light weight ablative parts and is some 5,000 pounds lighter than the Shuttle motor used to date. The payload performance of the ASRM-powered Shuttle is 12,000 pounds higher than that provided by the present motor. This is of particular benefit for payloads delivered to higher inclinations and/or altitudes. The ASRM facility uses state-of-the-art manufacturing techniques, including continuous propellant mixing and direct casting

    Combustion stability with baffles, absorbers and velocity sensitive combustion

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    Analytical and computational techniques were developed to predict the stability behavior of liquid propellant rocket combustors using damping devices such as acoustic liners, slot absorbers, and injector face baffles. Models were developed to determine the frequency and decay rate of combustor oscillations, the spatial and temporal pressure waveforms, and the stability limits in terms of combustion response model parameters

    Computer program determines thermal environment and temperature history of lunar orbiting space vehicles

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    Program computes the thermal environment of a spacecraft in a lunar orbit. The quantities determined include the incident flux /solar and lunar emitted radiation/, total radiation absorbed by a surface, and the resulting surface temperature as a function of time and orbital position

    NLTE 1.5D Modeling of Red Giant Stars

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    Spectra for 2D stars in the 1.5D approximation are created from synthetic spectra of 1D non-local thermodynamic equilibrium (NLTE) spherical model atmospheres produced by the PHOENIX code. The 1.5D stars have the spatially averaged Rayleigh-Jeans flux of a K3-4 III star, while varying the temperature difference between the two 1D component models (ΔT1.5D\Delta T_{\mathrm{1.5D}}), and the relative surface area covered. Synthetic observable quantities from the 1.5D stars are fitted with quantities from NLTE and local thermodynamic equilibrium (LTE) 1D models to assess the errors in inferred TeffT_{\mathrm{eff}} values from assuming horizontal homogeneity and LTE. Five different quantities are fit to determine the TeffT_{\mathrm{eff}} of the 1.5D stars: UBVRI photometric colors, absolute surface flux SEDs, relative SEDs, continuum normalized spectra, and TiO band profiles. In all cases except the TiO band profiles, the inferred TeffT_{\mathrm{eff}} value increases with increasing ΔT1.5D\Delta T_{\mathrm{1.5D}}. In all cases, the inferred TeffT_{\mathrm{eff}} value from fitting 1D LTE quantities is higher than from fitting 1D NLTE quantities and is approximately constant as a function of ΔT1.5D\Delta T_{\mathrm{1.5D}} within each case. The difference between LTE and NLTE for the TiO bands is caused indirectly by the NLTE temperature structure of the upper atmosphere, as the bands are computed in LTE. We conclude that the difference between TeffT_{\mathrm{eff}} values derived from NLTE and LTE modelling is relatively insensitive to the degree of the horizontal inhomogeneity of the star being modeled, and largely depends on the observable quantity being fit.Comment: 46 pages, 14 figures, 7 tables, accepted for publication in ApJ on April 5, 201

    The letters of Charlotte Mary Yonge (1823-1901) edited by Charlotte Mitchell, Ellen Jordan and Helen Schinske.

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    Charlotte Yonge is one of the most influential and important of Victorian women writers; but study of her work has been handicapped by a tendency to patronise both her and her writing, by the vast number of her publications and by a shortage of information about her professional career. Scholars have had to depend mainly on the work of her first biographer, a loyal disciple, a situation which has long been felt to be unsatisfactory. We hope that this edition of her correspondence will provide for the first time a substantial foundation of facts for the study of her fiction, her historical and educational writing and her journalism, and help to illuminate her biography and also her significance in the cultural and religious history of the Victorian age

    Comparison of high-resolution solar irradiance spectra and the solar luminosity in the period 1980-1989

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    In this research, we aim to determine to what extent the solar irradiance changes measured through the 1980's from orbiting vehicles are accompanied by spectroscopic irradiance changes observable from the ground. We describe fractional changes in line absorption as 'blanketing'. In section 2, we briefly review results obtained in an earlier project and which have been published. Section 3 describes the data of this investigation; section 4 describes the data reduction; section 5 describes the observational results in terms of blanketing; and section 6 describes the interpretation of the measured changes. Section 7 contains an outline of possible uses for Doppler-shift data that emerges with the measurements of the blanketing variations. Section 8 is an outline for future research suggested by our results in this project
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