9,777 research outputs found

    The Radon Monitoring System in Daya Bay Reactor Neutrino Experiment

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    We developed a highly sensitive, reliable and portable automatic system (H3^{3}) to monitor the radon concentration of the underground experimental halls of the Daya Bay Reactor Neutrino Experiment. H3^{3} is able to measure radon concentration with a statistical error less than 10\% in a 1-hour measurement of dehumidified air (R.H. 5\% at 25^{\circ}C) with radon concentration as low as 50 Bq/m3^{3}. This is achieved by using a large radon progeny collection chamber, semiconductor α\alpha-particle detector with high energy resolution, improved electronics and software. The integrated radon monitoring system is highly customizable to operate in different run modes at scheduled times and can be controlled remotely to sample radon in ambient air or in water from the water pools where the antineutrino detectors are being housed. The radon monitoring system has been running in the three experimental halls of the Daya Bay Reactor Neutrino Experiment since November 2013

    The Submillimeter Array

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    The Submillimeter Array (SMA), a collaborative project of the Smithsonian Astrophysical Observatory (SAO) and the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), has begun operation on Mauna Kea in Hawaii. A total of eight 6-m telescopes comprise the array, which will cover the frequency range of 180-900 GHz. All eight telescopes have been deployed and are operational. First scientific results utilizing the three receiver bands at 230, 345, and 690 GHz have been obtained and are presented in the accompanying papers.Comment: 10 pages, 4 figure

    Low-Temperatures Vortex Dynamics in Twinned Superconductors

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    We discuss the low-temperature dynamics of magnetic flux lines in samples with a family of parallel twin planes. A current applied along the twin planes drives flux motion in the direction transverse to the planes and acts like an electric field applied to {\it one-dimensional} carriers in disordered semiconductors. As in flux arrays with columnar pins, there is a regime where the dynamics is dominated by superkink excitations that correspond to Mott variable range hopping (VRH) of carriers. In one dimension, however, rare events, such as large regions void of twin planes, can impede VRH and dominate transport in samples that are sufficiently long in the direction of flux motion. In short samples rare regions can be responsible for mesoscopic effects.Comment: 4 pages, 2 figures email: [email protected]

    Development of a GIS Based Water Management Tool for a Large Scale Rice Irrigation Scheme

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    A GIS based model was developed to integrate the vast amounts of spatially distributed information from the Kerian Irrigation Scheme comprising eight compartments which are further subdivided into 28 blocks. The model consists of three modules. The "Scheduling" program computes irrigation deliveries based on spatial and temporal demand of the paddy field by each compartment, block or secondary canal. The "Monitoring" program gives information by compartment and by block on the uniformity of water distribution and the shortfall or excess. Relative Water Supply (RWS), Water Use Efficiency (WUE), Cumulative Relative Water Supply (CRWS), and Water Productivity Index (WPI) were computed by the "Evaluation" module. The post-season analysis uses weekly information on hydro-climatic parameters, irrigation delivery and irrigation indices by block within each compartment. On a weekly basis, RWS and WUE were found to range from 1.01 to 2.24 and 45% to 99% respectively in the main season and 1.01 to 1.87 and 53.57% to 96.15% respectively in the off season. The average values of RWS and WUE were found to be 1.53 and 68.15% in the main season and 1.33 and 78.47% in the off season respectively. The average values of WPI were also found to be 0.13 and 0.22 kg/m3 in the main season and off seasons respectively. Color-eoded thematic maps were produced for the monitoring of Seasonal Yields and Cropping Intensity (CI) by block and compartment of the scheme. The results are displayed allowing the manager to view maps, tables and graphs in a comprehensible form to ease decision making as the season progresses. This study would be useful to improve the irrigation system management based on feedback of field information

    395 OSTEOPHYTES AND JOINT SPACE NARROWING ARE INDEPENDENTLY ASSOCIATED WITH PAIN IN FINGER JOINTS IN HAND OSTEOARTHRITIS

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    Objective To study the associations between structural abnormalities on ultrasound (US) or conventional x-rays (CR) and pain in hand osteoarthritis (HOA). Methods In 55 consecutive patients with HOA (mean age 61 years, 86% women) fulfilling the American College of Rheumatology criteria, pain in 30 separate hand joints was assessed upon palpation; osteophytes were assessed by US and CR and joint space narrowing (JSN) by CR. Associations between structural abnormalities and pain per joint were analysed using generalised estimated equations to account for patient effects and adjusted for age, sex, body mass index, US inflammatory features and other remaining structural abnormalities. Results In 1649 joints, 69% and 46% had osteophytes on US and CR, respectively and 47% had JSN. Osteophytes and JSN showed independent associations with pain per joint adjusted: OR for osteophytes: 4.8 (95% CI 3.1 to 7.5) for US and 4.1 (95% CI 2.4 to 7.1) for CR; for JSN: 4.2 (95% CI 2.0 to 9.0). Conclusions Osteophytes and JSN are independently associated with pain in individual HOA joints, taking into account patient effects
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