25,703 research outputs found

    Severe storm electricity

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    Successful ground truth support of U-2 overflights was been accomplished. Data have been reduced for 4 June 1984 and some of the results have been integrated into some of MSFC's efforts. Staccato lightning (multiply branched, single stroke flash with no continuing current) is prevalent within the rainfree region around the main storm updraft and this is believed to be important, i.e., staccato flashes might be an important indicator of severe storm electrification. Results from data analysis from two stations appear to indicate that charge center heights can be estimated from a combination of intercept data with data from the fixed laboratory at NSSL. An excellent data base has been provided for determining the sight errors and efficiency of NSSL's LLP system. Cloud structures, observable in a low radar reflectivity region and on a scale smaller than is currently resolved by radar, which appear to be related to electrical activity are studied

    Angular intricacies in hot gauge field theories

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    It is argued that in hot gauge field theories, "Hard Thermal Loops" leading order calculations call for a definite sequence of angular averages and discontinuity (or Imaginary part prescription) operations, and run otherwise into incorrect results. The ten years old collinear singularity problem of hot QCDQCD, provides a striking illustration of that fate.Comment: 14 pages, 1 figur

    Magnetic reversals in a simple model of MHD

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    We study a simple magnetohydrodynamical approach in which hydrodynamics and MHD turbulence are coupled in a shell model, with given dynamo constrains in the large scales. We consider the case of a low Prandtl number fluid for which the inertial range of the velocity field is much wider than that of the magnetic field. Random reversals of the magnetic field are observed and it shown that the magnetic field has a non trivial evolution linked to the nature of the hydrodynamics turbulence.Comment: 4 pages, submitted to PR

    Synthesis, Reactions, and Properties of 1-Phenyl-2-Propen-1-ol Derivatives

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    The synthesis and chemical properties of some 1-phenyl-2- -propen-1-ol derivatives are described, with emphasis on the synthesis of 1-phenyl-2-propenyl type alkylating agents. Alkylation reactions of the ester enolate derived from methyl isobutyrate with isomeric 1-chloro-1-phenyl-2-propene and 1-chloro-3-phenyl-2- -propene, to give the same final product, is discussed in some detail
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