3,039 research outputs found

    Solar energy research and development program on the exploitation of the solar resource on the Reunion Island and its integration into an electrical power grid

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    Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.Reunion Island stands out by its specific energy context due to its growing population and a strong economic development. The main objective of this French region is to ensure that its exceptional potential for renewable power generation could meet an increasing energy demand. Regarding the energy development, the Regional strategy is to reach the energy independence by 2030 (SPL “Energies RĂ©union”) without using fossil fuels. In this context, the LE2P is leading a solar resource research programme with the aim to use solar resource as a stable source of energy and ensure its management in a reliable and efficient way for its integration into an electrical power grid. This paper aims to describe the methodology used for the development of this ambitious and challenging R&D program, projects articulation within the LE2P roadmap’s and the collaborations and partnerships initiated in UE and OI zone, permitting Eco city development especially in the IO area.cf201

    Research collaboration in solar radiometry between the University of Reunion Island and the University of Kwazulu-Natal

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    Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.Since 2012, the Universities of KwaZulu-Natal and Reunion Island have collaborated on a joint programme of solar energy research. The initiative has two principle aims: the development of solar forecasting techniques and the expansion of solar monitoring capabilities from continental Africa into the southern Indian Ocean region. In this paper, we introduce the programme and review the progress made. A key activity is performance validation of a low-cost radiometric sensor, the Delta-T Devices SPN1, which has been operated at a UKZN ground station for comparison against reference sensors. The instrument potentially represents an opportunity to expand existing radiometric networks by reducing the cost of ground station facilities. A novel feature of the device is its use of seven thermopile sensors and a stationery shading mask which together enable the simultaneous measurement of global horizontal and diffuse horizontal irradiance. It is important that the instrument performance should first be assessed, however, so that its measurement uncertainty is known ahead of deployment. Data from the UKZN trial are included in the paper, along with a description of a meteorological classification system that may be used in solar forecasting systems. The system is based on the direct solar fraction, that is, the ratio of direct horizontal irradiance to global horizontal irradiance. A clustering methodology is described and sample data are provided to illustrate the ability of the method to segregate days into statistically significant bins.cf201

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Technical design and characterization of a ground based solar metrology network on Reunion Island

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    Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.The roadmap of Reunion Island regarding energy is to reach autonomy by 2030. Obviously, renewable energies will play a key role in this ambitious project. However, a couple of years ago, a limit set by the French government relatively to the amount of lethal power injected on the electrical grid stopped the thrust: at any time, intermittent sources should not exceed 30 % of the whole production. This is due to the fragility of the grid: rugged topography, no interconnection. The University of La Reunion through the LE2P lab (Energy, Electronic and Process) decided to search a solution by predicting the solar resource in order to erase part of the intermittency of the production coming from the solar plants. Along this track, the first step is to evaluate precisely the resource and study its spatio-temporal variability. To do so, the LE2P gets engaged in deploying, at ground level, a network of monitoring stations. These units should be capable to produce field data responding to specific requirements in terms of acquisition frequency and quality, compatible with the clustering tools and mapping programs developed beside. Today, LE2P team manages a fleet of more than 15 stations, with various configurations, all over Reunion Island and plans to extend its network to neighboring territories. This article proposes to present in details the different components of a typical station, how they have been selected and how they are maintained. We will also see how the lab gets organized in order to propose top quality data to the solar scientific community.cf201

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon Ό\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, ΌΌ\mu\mu or eΌe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde
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