7,949 research outputs found

    Update, comparing different plate treatments and design

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    Eight electrochemical cells were tested for precycling capacity and compared. The cell design variables included teflon treatment, silver treatment, light loading, and a polypropylene separator. Data are presented in tabular form

    Recharge unit provides for optimum recharging of battery cells

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    Percent recharge unit permits each cell of a rechargeable battery to be charged to a preset capacity of the cell. The unit automatically monitors and controls a rechargeable battery subjected to charge-discharge cycling tests

    21st Century Simulation: Exploiting High Performance Computing and Data Analysis

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    This paper identifies, defines, and analyzes the limitations imposed on Modeling and Simulation by outmoded paradigms in computer utilization and data analysis. The authors then discuss two emerging capabilities to overcome these limitations: High Performance Parallel Computing and Advanced Data Analysis. First, parallel computing, in supercomputers and Linux clusters, has proven effective by providing users an advantage in computing power. This has been characterized as a ten-year lead over the use of single-processor computers. Second, advanced data analysis techniques are both necessitated and enabled by this leap in computing power. JFCOM's JESPP project is one of the few simulation initiatives to effectively embrace these concepts. The challenges facing the defense analyst today have grown to include the need to consider operations among non-combatant populations, to focus on impacts to civilian infrastructure, to differentiate combatants from non-combatants, and to understand non-linear, asymmetric warfare. These requirements stretch both current computational techniques and data analysis methodologies. In this paper, documented examples and potential solutions will be advanced. The authors discuss the paths to successful implementation based on their experience. Reviewed technologies include parallel computing, cluster computing, grid computing, data logging, OpsResearch, database advances, data mining, evolutionary computing, genetic algorithms, and Monte Carlo sensitivity analyses. The modeling and simulation community has significant potential to provide more opportunities for training and analysis. Simulations must include increasingly sophisticated environments, better emulations of foes, and more realistic civilian populations. Overcoming the implementation challenges will produce dramatically better insights, for trainees and analysts. High Performance Parallel Computing and Advanced Data Analysis promise increased understanding of future vulnerabilities to help avoid unneeded mission failures and unacceptable personnel losses. The authors set forth road maps for rapid prototyping and adoption of advanced capabilities. They discuss the beneficial impact of embracing these technologies, as well as risk mitigation required to ensure success

    Exact quantum cross sections for a three dimensional angle dependent model for three body reactions

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    Quantum mechanical reactive cross sections reported for three dimensional angle dependent model surfac

    SUPERSYMMETRY REACH OF AN UPGRADED TEVATRON COLLIDER

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    We examine the capability of a s=2\sqrt{s}=2 TeV Tevatron ppˉp\bar p collider to discover supersymmetry, given a luminosity upgrade to amass 25 fb125\ fb^{-1} of data. We compare with the corresponding reach of the Tevatron Main Injector (1 fb11\ fb^{-1} of data). Working within the framework of minimal supergravity with gauge coupling unification and radiative electroweak symmetry breaking, we first calculate the regions of parameter space accessible via the clean trilepton signal from \tw_1\tz_2\to 3\ell +\eslt production, with detailed event generation of both signal and major physics backgrounds. The trilepton signal can allow equivalent gluino masses of up to mtg600700m_{\tg}\sim 600-700 GeV to be probed if m0m_0 is small. If m0m_0 is large, then mtg500m_{\tg}\sim 500 GeV can be probed for μ0\mu 0 and large values of m0m_0, the rate for \tz_2\to\tz_1\ell\bar{\ell} is suppressed by interference effects, and there is {\it no} reach in this channel. We also examine regions where the signal from \tw_1\overline{\tw_1}\to \ell\bar{\ell}+\eslt is detectable. Although this signal is background limited, it is observable in some regions where the clean trilepton signal is too small. Finally, the signal \tw_1\tz_2\to jets+\ell\bar{\ell} +\eslt can confirm the clean trilepton signal in a substantial subset of the parameter space where the trilepton signal can be seen. We note that although the clean trilepton signal may allow Tevatron experiments to identify signals in regions of parameter space beyond the reach of LEP II, the dilepton channels generally probe much the same region as LEP II.Comment: 19 page REVTEX file; a uuencoded PS file with PS figures is available via anonymous ftp at ftp://hep.fsu.edu/preprints/baer/FSUHEP950301.u

    Is "just-so" Higgs splitting needed for t-b-\tau Yukawa unified SUSY GUTs?

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    Recent renormalization group calculations of the sparticle mass spectrum in the Minimal Supersymmetric Standard Model (MSSM) show that t-b-\tau Yukawa coupling unification at M_{\rm GUT} is possible when the mass spectra follow the pattern of a radiatively induced inverted scalar mass hierarchy. The calculation is entirely consistent with expectations from SO(10) SUSY GUT theories, with one exception: it seems to require MSSM Higgs soft term mass splitting at M_{\rm GUT}, dubbed "just-so Higgs splitting" (HS) in the literature, which apparently violates the SO(10) gauge symmetry. Here, we investigate three alternative effects: {\it i}). SO(10) D-term splitting, {\it ii}). inclusion of right hand neutrino in the RG calculation, and {\it iii}). first/third generation scalar mass splitting. By combining all three effects (the DR3 model), we find t-b-\tau Yukawa unification at M_{\rm GUT} can be achieved at the 2.5% level. In the DR3 case, we expect lighter (and possibly detectable) third generation and heavy Higgs scalars than in the model with HS. In addition, the light bottom squark in DR3 should be dominantly a right state, while in the HS model, it is dominantly a left state.Comment: 21 pages with 11 .eps figures; revised version added two reference

    Combustion chemistry of solid propellants

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    Several studies are described of the chemistry of solid propellant combustion which employed a fast-scanning optical spectrometer. Expanded abstracts are presented for four of the studies which were previously reported. One study of the ignition of composite propellants yielded data which suggested early ammonium perchlorate decomposition and reaction. The results of a study of the spatial distribution of molecular species in flames from uncatalyzed and copper or lead catalyzed double-based propellants support previously published conclusions concerning the site of action of these metal catalysts. A study of the ammonium-perchlorate-polymeric-fuel-binder reaction in thin films, made by use of infrared absorption spectrometry, yielded a characterization of a rapid condensed-phase reaction which is likely important during the ignition transient and the burning process
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