1,744 research outputs found

    Heavy quark damping rate in hot viscous QCD plasma

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    We derive an expression for the heavy quark damping rate in hot quark gluon plasma in presence of flow. Here all the bath particles here are out of equilibrium due to the existence of non-zero velocity gradient. The magnetic sector shows similar infrared divergences even after hard thermal loop corrections as one encounters in case of non-viscous plasma. We estimate the first order correction in (η/s\eta/s) for heavy quark damping rate due to the non-zero viscosity of the QCD plasma.Comment: 19 pages, 1 figure, accepted for publication in PR

    Next to leading order non Fermi liquid corrections to the neutrino emissivity and cooling of the neutron star

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    In this work we derive the expressions of the neutrino mean free path(MFP) and emissivity with non Fermi liquid corrections up to next to leading order(NLO) in degenerate quark matter. The calculation has been performed both for the absorption and scattering processes. Subsequently the role of these NLO corrections on the cooling of the neutron star has been demonstrated. The cooling curve shows moderate enhancement compared to the leading order(LO) non-Fermi liquid result. Although the overall correction to the MFP and emissivity are larger compared to the free Fermi gas, the cooling behavior does not alter significantly.Comment: 8 pages, 8 figures, references added, matches published versio

    Isospin mode splitting and mixing in asymmetric nuclear matter

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    We estimate exclusive density and asymmetry parameter dependent dispersion relations of various charged states of pions in asymmetric nuclear matter. The possibility of matter induced mixing of π0\pi^0 with η\eta is clearly exposed with the further mass modification of π0\pi^0 meson due to mixing. Asymmetry driven mass splitting and mixing amplitude are of the same order as the corresponding values in vacuum. Closed form analytic results for the mass shifts and dispersion relations with and without mixing are presented. Furthermore, we discuss the sensitivity of our results on the scalar mean field within the framework of Quantum Hadrodynamics.Comment: 8 pages, 4 Figure

    Validity of the Generalized Second Law of Thermodynamics of the Universe Bounded by the Event Horizon in Brane Scenario

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    In this paper, we examine the validity of the generalized second law of thermodynamics (GSLT) of the universe bounded by the event horizon in brane-world gravity. Here we consider homogeneous and isotropic model of the universe filled with perfect fluid in one case and in another case holographic dark energy model of the universe has been considered. The conclusions are presented point wise.Comment: 8 pages, the paper has been accepted in EPJC for publication. Conclusion has been modified an some references have been adde

    Study of Velocity and Materials on Tribocharging of Polymer Powders for Powder Coating Applications

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    Electrostatic powder deposition is widely used in a plethora of industrial-applications ranging from the pharmaceutical and food.industries, to farm equipment and automotive applications. The disadvantages of this technique are possible back corona (pin-like formations) onset and the Faraday penetration limitation (when the powder does not penetrate in some recessed areas). A possible solution to overcome these problems is to use tribochargers to electrostatically charge the powder. Tribocharging, or contact charging while two materials are in contact, is related to the work function difference between the contacting materials and generates bipolarly charged particles. The generation of an ion-free powder cloud by tribocharging with high bipolar charge and an overall charge density of almost zero, provides a better coverage of the recessed areas. In this study, acrylic and epoxy powders were fluidized and charged by passing through stainless steel, copper, aluminum, and polycarbonate static mixers, respectively. The particle velocity was varied to determine its effect on the net charge-to-mass ratio (QIM) acquired by the powders. In general, the Q/M increases rapidly when the velocity was increased from 1.5 to 2.5 m/s, remaining almost constant for higher velocities. Charge separation experiments showed bipolar charging for all chargers

    Carbide precipitates in solution-quenched PH13-8 Mo stainless steel: a small-angle neutron scattering investigation

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    This paper deals with the small-angle neutron scattering (SANS) investigation on solution-quenched PH13-8 Mo stainless steel. From the nature of the variation of the functionality of the profiles for varying specimen thickness and also from the transmission electron microscopy (TEM), it has been established that the small-angle scattering signal predominantly originates from the block-like metallic carbide precipitates in the specimen. The contribution due to double Bragg reflection is not significant in the present case. The single scattering profile has been extracted from the experimental profiles corresponding to different values of specimen thickness. In order to avoid complexity and non-uniqueness of the multi-parameter minimization for randomly oriented polydisperse block-like precipitate model, the data have been analyzed assuming randomly oriented polydisperse cylindrical particle model with a locked aspect ratio

    Mars Dust: Characterization of Particle Size and Electrostatic Charge Distribution

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    Some of the latest pictures of Mars surface sent by NASA's Spirit rover in early January, 2004, show very cohesive, "mud-like" dust layers. Significant amounts of dust clouds are present in the atmosphere of Mars [1-4]. NASA spacecraft missions to Mars confirmed hypotheses from telescopic work that changes observed in the planet's surface markings are caused by wind-driven redistribution of dust. In these dust storms, particles with a wide range of diameters (less than 1 micrometer to 50 micrometers) are a serious problem to solar cells, spacecraft, and spacesuits. Dust storms may cover the entire planet for an extended period of time [5]. It is highly probable that the particles are charged electrostatically by triboelectrification and by UV irradiation

    Cardiorespiratory and Neuromuscular Effects of Freshwater Cyanophyte Anabena flosaquae in Rats

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    Anatoxin-a, recognised as a potent toxin warfare agent, is considered as a weapon of mass destruction due to its lethal anticholinesterase activity. The intravenous administration of cell-free extract of Anabena flosaquae UTEX-2383(anatoxin-a) produced a transient vasodepressor response followed by a sustained rise in blood pressure. The vasodepressor effect was potentiated by physostigmine and antagonised by atropine and bilateral vagotomy, suggesting the involvement of cholinergic system. On the contrary, the vasopressor response was antagonised by hexamethonium prazosin and hemicholinium-3, indicating that the toxin stimulates the sympathetic system through the release of catecholamines from nerve endings. Prolonged apnoea with attendant bronchoconstriction was observed corresponding to bradycardia and vasppressor response which remained unaltered by atropine while antagonised by bilateral vagotomy. The extract when administered intra-arterially did not modify the apnoea induced by veratridine; but phenyldiguanide potentiated the bronchoconstriction, indicating the involvement of pulmonary vagal afferents. The extract produced a dose- and time-dependent blockade of indirect muscle twitch recorded from gastrocnemius muscle. The neuromuscular blockade was potentiated by neostigmine but unaltered by DTC
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