3,650 research outputs found

    Mixing, conveying and injection molding hybrid system for conductive polymer composites

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    The demand for conductive fuel cell stack components contributed to the research and development of composite materials and technologies. Significant activities were directed to the study of low-cost bipolar plates made in thermosets and thermoplastics manufactured by compression and injection molding. For the production of conductive thermoplastics carbon-polymers composites are used methods including thermokineting, twin screw extruder, or Banbury type mixing. In this paper are presented the results of research of a technology combining the mixing of the pellets of a composite carbon black in a polymer matrix with expanded graphite and conveying the compound to the injection molding unit and then, the melt injection molded into a micro-channel bipolar plate for a proton exchange membrane fuel cell (PEMFC)

    OGSA/Globus Evaluation for Data Intensive Applications

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    We present an architecture of Globus Toolkit 3 based testbed intended for evaluation of applicability of the Open Grid Service Architecture (OGSA) for Data Intensive Applications.Comment: To be published in the proceedings of the XIX International Symposium on Nuclear Electronics and Computing (NEC'2003), Bulgaria, Varna, 15-20 September, 200

    A method to localize gamma-ray bursts using POLAR

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    The hard X-ray polarimeter POLAR aims to measure the linear polarization of the 50-500 keV photons arriving from the prompt emission of gamma-ray bursts (GRBs). The position in the sky of the detected GRBs is needed to determine their level of polarization. We present here a method by which, despite of the polarimeter incapability of taking images, GRBs can be roughly localized using POLAR alone. For this purpose scalers are attached to the output of the 25 multi-anode photomultipliers (MAPMs) that collect the light from the POLAR scintillator target. Each scaler measures how many GRB photons produce at least one energy deposition above 50 keV in the corresponding MAPM. Simulations show that the relative outputs of the 25 scalers depend on the GRB position. A database of very strong GRBs simulated at 10201 positions has been produced. When a GRB is detected, its location is calculated searching the minimum of the chi2 obtained in the comparison between the measured scaler pattern and the database. This GRB localization technique brings enough accuracy so that the error transmitted to the 100% modulation factor is kept below 10% for GRBs with fluence Ftot \geq 10^(-5) erg cm^(-2) . The POLAR localization capability will be useful for those cases where no other instruments are simultaneously observing the same field of view.Comment: 13 pages, 10 figure

    The KLASH Proposal

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    We propose a search of galactic axions with mass about 0.2 µeV using a large volume resonant cavity, about 50 m3, cooled down to 4 K and immersed in a moderate axial magnetic field of about 0.6 T generated inside the superconducting magnet of the KLOE experiment [1] located at the National Laboratory of Frascati of INFN. This experiment, called KLASH (KLoe magnet for Axion SearcH) in the following, has a potential sensitivity on the axion-to-photon coupling, gaγγ, of about 6 × 10−17 GeV−1, reaching the region predicted by KSVZ [2] and DFSZ [3] models of QCD axions

    Sulphonylureas and cancer: a case-control study.

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