81,123 research outputs found

    Suppression of the high pTp_T charged hadron RAAR_{AA} at the LHC

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    We present a parameter free postdiction of the high-pTp_T charged-hadron nuclear modification factor (RAAR_{AA}) in two centralities, measured by the CMS collaboration in PbPb-PbPb collisions at the Large Hadron Collider (LHC). The evolution of the bulk medium is modeled using viscous fluid dynamics, with parameters adjusted to describe the soft hadron yields and elliptic flow. Assuming the dominance of radiative energy loss, we compute the medium modification of the RAAR_{AA} using a perturbative QCD based formalism, the higher twist scheme. The transverse momentum diffusion coefficient q^\hat{q} is assumed to scale with the entropy density and normalized by fitting the RAAR_{AA} in the most central AuAu-AuAu collisions at the Relativistic Heavy-Ion Collider (RHIC). This set up is validated in non-central AuAu-AuAu collisions at RHIC and then extrapolated to PbPb-PbPb collisions at the LHC, keeping the relation between q^\hat{q} and entropy density unchanged. We obtain a satisfactory description of the CMS RAAR_{AA} over the pTp_{T} range from 10-100 GeV.Comment: 4 pages, 3 figures, revtex4, new experimental data used, new calculations with systematic error bands, changed abstract and contents, conclusions unchange

    A silicone column for GC analysis of polar and nonpolar chemicals

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    The investigation of the Saturnian System is being proposed jointly by NASA and the European Space Agency (ESA). The mission is scheduled for a launch in 1996. The mission provides an opportunity for close observation and exploration of Saturn's atmosphere, the complex Saturnian System of satellites and rings, Titan (Saturn's planet-sized moon), and Saturn's magnetosphere. The mission gives special attention to Titan which is blanketed by a thick, opaque atmosphere. An atmospheric probe will be deposited into the Titan Atmosphere for in situ measurement during a slow, three hour descent to the surface. The results from this analysis may provide the information which is important to the research of chemical evolution, and the origin of life. An analytical system was developed as a part of the Titan Aerosol Gas Experiment (TAGEX), a proposed experiment for the Cassini Mission. This system will use two highly sensitive detectors, the Metastable Ionization Detector (MID) and the Ion Mobility Spectrometer (IMS). Unfortunately, when commercial columns are utilized with these highly sensitive detectors, volatile components continuously bleed from the column and interfere with the detector. In addition, light columns must be able to separate polar and nonpolar organic chemicals within 10-15 minutes under isothermal conditions for the Titan Mission. Therefore, a highly crosslinked silicone polymeric packed column was developed which is able to efficiently separate amines, alcohols, and hydrocarbons with retention times less that 15 minutes at 100 C isothermal condition

    Transient Dynamics and Thermal Stress for Nuclear Rocket Heat-exchanger

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    Transient dynamics and thermal stresses in nuclear rocket heat exchange

    A Comparison Between the Variational Solution and the Experimental Data

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    Current distribution on dipole antenna with nonreflecting resistive loading, expressed using variation metho

    An experimental study of imperfectly conducting dipoles

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    Input admittances of imperfectly conducting dipole antennas measured in ultrahigh frequency rang

    The control of absorption cross-section for a nuclear rocket

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    Control of absorption cross section of nuclear rocket with distributed parameter kinetics using two optimization procedure

    Distributed parameter type of control for a bilinear system

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    Optimal control laws for bilinear system in distributed parameter model - analytical determinatio
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