4,515 research outputs found

    Pure xenon hexafluoride prepared for thermal properties studies

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    Preparation of a xenon hexafluoride and sodium fluoride salt yields a sample of the highest possible purity for use in thermal measurements. The desired hexafluoride can easily be freed from the common contaminants, xenon tetra-fluoride, xenon difluoride, and xenon oxide tetrafluoride, because none of these compounds reacts with sodium fluoride

    The "Rail-Unloading" Problem

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    The "Rail-Unloading" Problem deals with a heavy beam of infinite or semi-infinite length, which is placed on both sides of a supporting point on planes with different levels. Analytical expressions for the contact lengths on both sides of the supporting point as well as for the maximum bending moment are presented

    Income Distribution Analysis for Rural Central Java: an Application of Social Accounting Methodology

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    IndonesianKetimpangan pendapatan merupakan masalah besar di negara-negara berkembang. Seringkali, kelompok-kelompok tertentu seperti wanita dan buruh tani mendapat perhatian khusus dalam analisa distribusi pendapatan. Tujuan penelitian ini adalah untuk menelusuri sumber-sumber pendapatan dari kelompok sasaran dengan menggunakan Social Accounting Matrix. Hasil analisis menunjukkan hubungan langsung dan tidak langsung antara aktivitas, komoditas dan faktor-faktor produksi dengan pendapatan serta pengaruh distribusinya diantara kelompok-kelompok sasaran

    Codeless GPS Applications to Multi-Path: CGAMP

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    Cordless Global Positioning System (GPS) Applications to Multi-Path (CGAMP) is meeting the challenge of exploiting the L-band signals from the Global Positioning System (GPS) satellites for the measurement of the impulse response of radio transmission channels over space-Earth paths. This approach was originally suggested by E. K. Smith and has been pursued by J. Lemmon, without an affordable implementation being identifiable. In addition to the high cost of a suitable P code correlating GPS receiver, there is also the major impediment of the often announced Department of Defense policy of selective availability/anti-spoof (SA/AS) that clouds reliable access to the wideband (20 MHz) P channel of the GPS signals without cryptographic access. A technique proposed by MacDoran utilizes codeless methods for exploiting the P channel signals implemented by the use of a pair of antennas and cross correlation signal detection

    Analysis of GPS radio occultation data from the FORMOSAT-3/COSMIC and Metop/GRAS missions at CDAAC

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    This study investigates the noise level and mission-to-mission stability of Global Positioning System (GPS) radio occultation (RO) neutral atmospheric bending angle data at the UCAR COSMIC Data Analysis and Archive Center (CDAAC). Data are used from two independently developed RO instruments currently flying in orbit on the FORMOSAT-3/COSMIC (F3C) and Metop/GRAS (GNSS Receiver for Atmospheric Sounding) missions. The F3C 50 Hz RO data are post-processed with a single-difference excess atmospheric phase algorithm, and the Metop/GRAS 50 Hz closed loop and raw sampling (down-sampled from 1000 Hz to 50 Hz) data are processed with a zero-difference algorithm. The standard deviations of the F3C and Metop/GRAS bending angles from climatology between 60 and 80 km altitude from June–December 2009 are approximately 1.78 and 1.13 μrad, respectively. The F3C standard deviation reduces significantly to 1.44 μrad when single-difference processing uses GPS satellites on the same side of the spacecraft. The higher noise level for F3C bending angles can be explained by additional noise from the reference link phase data that are required with single-difference processing. The F3C and Metop/GRAS mean bending angles differences relative to climatology during the same six month period are statistically significant and have values of −0.05 and −0.02 μrad, respectively. A comparison of ~13 500 collocated F3C and Metop/GRAS bending angle profiles over this six month period shows a similar mean difference of ~0.02 ± 0.02 μrad between 30 and 60 km impact heights that is marginally significant. The observed mean difference between the F3C and Metop/GRAS bending angles of ~0.02–0.03 μrad is quite small and illustrates the high degree of re-produceability and mission independence of the GPS RO data at high altitudes. Collocated bending angles between two F3C satellites from early in the mission differ on average by up to 0.5% near the surface due to systematically lower signal-to-noise ratio for one of the satellites. Results from F3C and Metop/GRAS differences in the lower troposphere suggest the Metop/GRAS bending angles are negatively biased compared to F3C with a maximum of several percents near the surface in tropical regions. This bias is related to different tracking depths (deeper in F3C) and data gaps in Metop/GRAS which make it impossible to process the data from both missions in exactly the same way

    Radon mitigation during the installation of the CUORE 0νββ0\nu\beta\beta decay detector

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    CUORE - the Cryogenic Underground Observatory for Rare Events - is an experiment searching for the neutrinoless double-beta (0νββ0\nu\beta\beta) decay of 130^{130}Te with an array of 988 TeO2_2 crystals operated as bolometers at ∼\sim10 mK in a large dilution refrigerator. With this detector, we aim for a 130^{130}Te 0νββ0\nu\beta\beta decay half-life sensitivity of 9×10259\times10^{25} y with 5 y of live time, and a background index of ≲10−2\lesssim 10^{-2} counts/keV/kg/y. Making an effort to maintain radiopurity by minimizing the bolometers' exposure to radon gas during their installation in the cryostat, we perform all operations inside a dedicated cleanroom environment with a controlled radon-reduced atmosphere. In this paper, we discuss the design and performance of the CUORE Radon Abatement System and cleanroom, as well as a system to monitor the radon level in real time.Comment: 10 pages, 6 figures, 1 tabl

    Comparing and improving hybrid deep learning algorithms for identifying and locating primary vertices

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    Using deep neural networks to identify and locate proton-proton collision points, or primary vertices, in LHCb has been studied for several years. Preliminary results demonstrated the ability for a hybrid deep learning algorithm to achieve similar or better physics performances compared to standard heuristic approaches. The previously studied architectures relied directly on hand-calculated Kernel Density Estimators (KDEs) as input features. Calculating these KDEs was slow, making use of the DNN inference engines in the experiment's real-time analysis (trigger) system problematic. Here we present recent results from a high-performance hybrid deep learning algorithm that uses track parameters as input features rather than KDEs, opening the path to deployment in the real-time trigger system.Comment: Proceedings for the ACAT 2022 conferenc
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