276 research outputs found

    Development of a 1 kW Gravitational Water Vortex Hydropower Plant Prototype

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    A pilot testing of a Gravitational Water Vortex Hydropower Plant (GWVHP) has been done to evaluate the applicability in a real-world scenario and validate the results from the lab-scale model. A scaled-up model of a capacity of 1 kW was constructed for the evaluation purpose. The test provided data in good agreement with a lab-scale model and a proper visualization to install Gravitational Water Vortex in real-world scenarios. The project lasted for nearly four months and thus provided important information on the problems that might arise in scaling up the lab model to a micro-hydro system. The pilot testing shows an overall plant efficiency of 49%, validating the lab-based studies conducted beforehand. The information obtained from this pilot study shall be implemented in a micro-hydro project on a larger scale

    Inference of Convergent Gene Acquisition Among Pseudomonas syringae Strains Isolated From Watermelon, Cantaloupe, and Squash

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    Pseudomonas syringae sensu strict , (phylogroup 2; referred to as P. syringae) consists of an environmentally ubiquitous bacterial population associated with diseases of numerous plant species. Recent studies using multilocus sequence analysis have indicated the clonal expansion of several P. syringae lineages, located in phylogroups 2a and 2b, in association with outbreaks of bacterial spot disease of watermelon, cantaloupe, and squash in the United States. To investigate the evolutionary processes that led to the emergence of these epidemic lineages, we sequenced the genomes of six P. syringae strains that were isolated from cucurbits grown in the United States, Europe, and China over a period of more than a decade, as well as eight strains that were isolated from watermelon and squash grown in six different Florida counties during the 2013 and 2014 seasons. These data were subjected to comparative analyses along with 42 previously sequenced genomes of P. syringae stains collected from diverse plant species and environments available from GenBank. Maximum likelihood reconstruction of the P. syringae core genome revealed the presence of a hybrid phylogenetic group, comprised of cucurbit strains collected in Florida, Italy, Serbia, and France, which emerged through genome-wide homologous recombination between phylogroups 2a and 2b. Functional analysis of the recombinant core genome showed that pathways involved in the ATP-dependent transport and metabolism of amino acids, bacterial motility, and secretion systems were enriched for recombination. A survey of described virulence factors indicated the convergent acquisition of several accessory type 3 secreted effectors (T3SEs) among phylogenetically distinct lineages through integrative and conjugative element and plasmid loci. Finally, pathogenicity assays on watermelon and squash showed qualitative differences in virulence between strains of the same clonal lineage, which correlated with T3SEs acquired through various mechanisms of horizontal gene transfer (HGT). This study provides novel insights into the interplay of homologous recombination and HGT toward pathogen emergence and highlights the dynamic nature of P. syringae sensu lato genomes

    Measurements of double-helicity asymmetries in inclusive J/ψJ/\psi production in longitudinally polarized p+pp+p collisions at s=510\sqrt{s}=510 GeV

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    We report the double helicity asymmetry, ALLJ/ψA_{LL}^{J/\psi}, in inclusive J/ψJ/\psi production at forward rapidity as a function of transverse momentum pTp_T and rapidity y|y|. The data analyzed were taken during s=510\sqrt{s}=510 GeV longitudinally polarized pp++pp collisions at the Relativistic Heavy Ion Collider (RHIC) in the 2013 run using the PHENIX detector. At this collision energy, J/ψJ/\psi particles are predominantly produced through gluon-gluon scatterings, thus ALLJ/ψA_{LL}^{J/\psi} is sensitive to the gluon polarization inside the proton. We measured ALLJ/ψA_{LL}^{J/\psi} by detecting the decay daughter muon pairs μ+μ\mu^+ \mu^- within the PHENIX muon spectrometers in the rapidity range 1.2<y<2.21.2<|y|<2.2. In this kinematic range, we measured the ALLJ/ψA_{LL}^{J/\psi} to be 0.012±0.0100.012 \pm 0.010~(stat)~±\pm~0.0030.003(syst). The ALLJ/ψA_{LL}^{J/\psi} can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken xx: one at moderate range x0.05x \approx 0.05 where recent RHIC data of jet and π0\pi^0 double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-xx region x2×103x \approx 2\times 10^{-3}. Thus our new results could be used to further constrain the gluon polarization for x<0.05x< 0.05.Comment: 335 authors, 10 pages, 4 figures, 3 tables, 2013 data. Version accepted for publication by Phys. Rev. D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    L\'evy-stable two-pion Bose-Einstein correlations in sNN=200\sqrt{s_{_{NN}}}=200 GeV Au++Au collisions

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    We present a detailed measurement of charged two-pion correlation functions in 0%-30% centrality sNN=200\sqrt{s_{_{NN}}}=200 GeV Au++Au collisions by the PHENIX experiment at the Relativistic Heavy Ion Collider. The data are well described by Bose-Einstein correlation functions stemming from L\'evy-stable source distributions. Using a fine transverse momentum binning, we extract the correlation strength parameter λ\lambda, the L\'evy index of stability α\alpha and the L\'evy length scale parameter RR as a function of average transverse mass of the pair mTm_T. We find that the positively and the negatively charged pion pairs yield consistent results, and their correlation functions are represented, within uncertainties, by the same L\'evy-stable source functions. The λ(mT)\lambda(m_T) measurements indicate a decrease of the strength of the correlations at low mTm_T. The L\'evy length scale parameter R(mT)R(m_T) decreases with increasing mTm_T, following a hydrodynamically predicted type of scaling behavior. The values of the L\'evy index of stability α\alpha are found to be significantly lower than the Gaussian case of α=2\alpha=2, but also significantly larger than the conjectured value that may characterize the critical point of a second-order quark-hadron phase transition.Comment: 448 authors, 25 pages, 11 figures, 4 tables, 2010 data. v2 is version accepted for publication in Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
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