301 research outputs found

    Visitors' preferences of renewable energy options in 'green' hotels.

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    Tourism belongs to the industries with significant energy consumption. Visitors as well as hotel managers have, however, a positive attitude towards the responsible use of energy resources. The level of research on visitors’ preferences of using different types of renewable energy is low, unlike findings on factual characteristics of conventional and renewable energies. That is why our aim was to assess visitors’ preferences of environmentally friendly energy sources in hotels. Preferences of six types of renewable energy - “green” tariff energy, solar panels on the rooftops, solar panels on the ground, heat pumps, AD, wind turbine, were measured at four tourist destinations in the Czech Republic. The positive attitude of tourists towards the selected types of energy sources was confirmed. The highest preferences were found for solar panels installed on the rooftops. A typology of preferences was revealed by cluster analysis and differences between clusters were tested for independent variables. Clusters of visitors with a high and low interest in any type of renewable energy were identified as well as a cluster of visitors with interest in all types apart from solar panels installed on the ground - the visitor’s origin was found as the main differentiation factor

    Strangelet search at RHIC

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    Two position sensitive Shower Maximum Detector (SMDs) for Zero-Degree Calorimeters (ZDCs) were installed by STAR before run 2004 at both upstream and downstream from the interaction point along the beam axis where particles with small rigidity are swept away by strong magnetic field. The ZDC-SMDs provides information about neutral energy deposition as a function of transverse position in ZDCs. We report the preliminary results of strangelet search from a triggered data-set sampling 100 million Au+Au collisions at top RHIC energy.Comment: Strange Quark Matter 2004 conference proceedin

    Transverse momentum and collision energy dependence of high pTp_{T} hadron suppression in Au+Au collisions at ultrarelativistic energies

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    We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at \sqrtsNN=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5\lt\pT\lt12 GeV/c. The collision energy dependence of the yields and the centrality and \pT dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of \pT-dependent suppression, which may be expected from models incorporating jet attentuation in cold nuclear matter or scattering of fragmentation hadrons.Comment: Final journal version. Data tables for figures may be downloaded from the STAR home page: http://www.star.bnl.gov --> Publications --> Access to STAR published dat

    Correlations in STAR: interferometry and event structure

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    STAR observes a complex picture of RHIC collisions where correlation effects of different origins -- initial state geometry, semi-hard scattering, hadronization, as well as final state interactions such as quantum intensity interference -- coexist. Presenting the measurements of flow, mini-jet deformation, modified hadronization, and the Hanbury Brown and Twiss effect, we trace the history of the system from the initial to the final state. The resulting picture is discussed in the context of identifying the relevant degrees of freedom and the likely equilibration mechanism.Comment: 8 pages, 6 figures, plenary talk at the 5th International Conference on Physics and Astrophysics of Quark Gluon Plasma, to appear in Journal of Physics G (http://www.iop.org

    Pion interferometry in Au+Au collisions at sNN\sqrt{\mathrm{s}_{_{\mathrm{NN}}}} = 200 GeV

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    We present a systematic analysis of two-pion interferometry in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV using the STAR detector at RHIC. We extract the HBT radii and study their multiplicity, transverse momentum, and azimuthal angle dependence. The Gaussianess of the correlation function is studied. Estimates of the geometrical and dynamical structure of the freeze-out source are extracted by fits with blast wave parameterizations. The expansion of the source and its relation with the initial energy density distribution is studied.Comment: 21 pages, 30 figures. As published in Physics Review

    Evidence from d+Au measurements for final-state suppression of high pTp_T hadrons in Au+Au collisions at RHIC

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    We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high pTp_T) in minimum bias and central d+Au collisions at sNN\sqrt{s_{NN}}=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high pTp_T previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.Comment: Final journal version. Data tables for figures may be downloaded from the STAR home page: http://www.star.bnl.gov --> Publications --> Access to STAR published dat

    Multiplicity and Pseudorapidity Distributions of Charged Particles and Photons at Forward Pseudorapidity in Au + Au Collisions at sqrt{s_NN} = 62.4 GeV

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    We present the centrality dependent measurement of multiplicity and pseudorapidity distributions of charged particles and photons in Au + Au collisions at sqrt{s_NN} = 62.4 GeV. The charged particles and photons are measured in the pseudorapidity region 2.9 < eta < 3.9 and 2.3 < eta < 3.7, respectively. We have studied the scaling of particle production with the number of participating nucleons and the number of binary collisions. The photon and charged particle production in the measured pseudorapidity range has been shown to be consistent with energy independent limiting fragmentation behavior. The photons are observed to follow a centrality independent limiting fragmentation behavior while for the charged particles it is centrality dependent. We have carried out a comparative study of the pseudorapidity distributions of positively charged hadrons, negatively charged hadrons, photons, pions, net protons in nucleus--nucleus collisions and pseudorapidity distributions from p+p collisions. From these comparisons we conclude that baryons in the inclusive charged particle distribution are responsible for the observed centrality dependence of limiting fragmentation. The mesons are found to follow an energy independent behavior of limiting fragmentation while the behavior of baryons seems to be energy dependent.Comment: 17 pages and 20 figure

    Transverse-momentum dependent modification of dynamic texture in central Au+Au collisions at sqrt(S_NN)=200 GeV

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    Correlations in the hadron distributions produced in relativistic Au+Au collisions are studied in the discrete wavelet expansion method. The analysis is performed in the space of pseudorapidity (|eta| < 1) and azimuth (full 2 pi) in bins of transverse momentum (p_t) from 0.14 < p_t < 2.1 GeV/c. In peripheral Au+Au collisions a correlation structure ascribed to mini-jet fragmentation is observed. It evolves with collision centrality and p_t in a way not seen before which suggests strong dissipation of minijet fragmentation in the longitudinally-expanding medium.Comment: 6 pages, 3 figure, accepted as Phys.Rev.C Rapid Communication. This version fixes journal style issue

    Particle-type dependence of azimuthal anisotropy and nuclear modification of particle production in Au+Au collisions at s(NN)**(1/2) = 200-GeV

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    We present STAR measurements of the azimuthal anisotropy parameter v2v_2 and the binary-collision scaled centrality ratio RCPR_{CP} for kaons and lambdas (Λ+Λˉ\Lambda+\bar{\Lambda}) at mid-rapidity in Au+Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. In combination, the v2v_2 and RCPR_{CP} particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish pT5p_T \approx 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The KS0K_S^0 and Λ+Λˉ\Lambda+\bar{\Lambda} v2v_2 values are consistent with expectations of constituent-quark-number scaling from models of hadron fromation by parton coalescence or recombination.Comment: 6 pages, 4 figures, 1 table. As published in PRL on Feb. 2, 2004; Significant revisions have been made to the text and color has been added to plot

    Rapidity and centrality dependence of proton and antiproton production from 197Au + 197Au collisions at √SNN = 130 GeV

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    We report on the rapidity and centrality dependence of proton and antiproton transverse mass distributions from 197Au + 197Au collisions at sqrt[sNN ]=130 GeV as measured by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Our results are from the rapidity and transverse momentum range of |y| <0.5 and 0.35< pt <1.00 GeV/c . For both protons and antiprotons, transverse mass distributions become more convex from peripheral to central collisions demonstrating characteristics of collective expansion. The measured rapidity distributions and the mean transverse momenta versus rapidity are flat within |y| <0.5 . Comparisons of our data with results from model calculations indicate that in order to obtain a consistent picture of the proton (antiproton) yields and transverse mass distributions the possibility of prehadronic collective expansion may have to be taken into account
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