7,838 research outputs found

    Low-energy three-body charge transfer reactions with Coulomb interaction in the final state

    Get PDF
    Three-body charge transfer reactions with Coulomb interaction in the final state are considered in the framework of coordinate-space integro-differential Faddeev-Hahn-type equations within two- and six-state close coupling approximations. The method is employed to study direct muon transfer in low-energy collisions of the muonic hydrogen HÎĽ_\mu by helium (He++^{++}) and lithium (Li+++^{+++}) nuclei. The experimentally observed isotopic dependence is reproduced.Comment: 14 pages REVTeX, accepted for publication in Journal of Physics

    CMS endcap RPC gas gap production for upgrade

    Get PDF
    The CMS experiment will install a RE4 layer of 144 new Resistive Plate Chambers (RPCs) on the existing york YE3 at both endcap regions to trigger high momentum muons from the proton-proton interaction. In this paper, we present the detailed procedures used in the production of new RPC gas gaps adopted in the CMS upgrade. Quality assurance is enforced as ways to maintain the same quality of RPC gas gaps as the existing 432 endcap RPC chambers that have been operational since the beginning of the LHC operation

    Low-energy quenching of positronium by helium

    Get PDF
    Very low-energy scattering of orthopositronium by helium has been investigated for simultaneous study of elastic cross section and pick-off quenching rate using a model exchange potential. The present calculational scheme, while agrees with the measured cross section of Skalsey et al, reproduces successfully the parameter ^ 1Z_{\makebox{eff}}, the effective number of electrons per atom in a singlet state relative to the positron. Together with the fact that this model potential also leads to an agreement with measured medium energy cross sections of this system, this study seems to resolve the long-standing discrepancy at low energies among different theoretical calculations and experimental measurements.Comment: 4 latex pages, 3 postscript figure

    A Carbon Corrosion Model to Evaluate the Effect of Steady State and Transient Operation of a Polymer Electrolyte Membrane Fuel Cell

    Full text link
    A carbon corrosion model is developed based on the formation of surface oxides on carbon and platinum of the polymer electrolyte membrane fuel cell electrode. The model predicts the rate of carbon corrosion under potential hold and potential cycling conditions. The model includes the interaction of carbon surface oxides with transient species like OH radicals to explain observed carbon corrosion trends under normal PEM fuel cell operating conditions. The model prediction agrees qualitatively with the experimental data supporting the hypothesis that the interplay of surface oxide formation on carbon and platinum is the primary driver of carbon corrosion

    Performance of the Gas Gain Monitoring system of the CMS RPC muon detector and effective working point fine tuning

    Full text link
    The Gas Gain Monitoring (GGM) system of the Resistive Plate Chamber (RPC) muon detector in the Compact Muon Solenoid (CMS) experiment provides fast and accurate determination of the stability in the working point conditions due to gas mixture changes in the closed loop recirculation system. In 2011 the GGM began to operate using a feedback algorithm to control the applied voltage, in order to keep the GGM response insensitive to environmental temperature and atmospheric pressure variations. Recent results are presented on the feedback method used and on alternative algorithms

    Economic and health burden of brucellosis in Kazakhstan

    Full text link
    Brucellosis is a widespread zoonotic disease considered as an emerging and re-emerging disease with a resulting threat of public health and animal health. Official reports document an animal incidence in Kazakhstan of about 0.6% per year, and the country still registers high number of human cases annually . The main objective of this paper was to evaluate the distribution and economic impact of brucellosis in Kazakhstan. We analysed human disease incidence data obtained from the Government Sanitary & Epidemiological Service with the aim to estimate the burden of disease in terms of disability-adjusted life years (DALYs). We also estimated the economic impact in terms of monetary losses. Additionally, we mapped the geographical distribution of the disease throughout Kazakhstan. In total, 1,334 human cases of brucellosis were registered in 2015 in Kazakhstan that resulted in 713 DALYs. Around US Dollar 21 million was spent on compensation for animals that had to be slaughtered due to brucellosis, and an additional US Dollar 24 million was spent on testing animals. Animal brucellosis and human brucellosis occur throughout the whole country, some trends of which are reviewed in this paper. We estimated the burden of the disease and explored possible explanation for high human incidence rates. This paper is the first to estimate the human burden of disease and the economic costs in Kazakhstan. Both of these are substantial
    • …
    corecore