217 research outputs found

    Fuel cells as an energy source for desalination applications.

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    Nowadays, there is a renewed interest in fuel cell technology from industry and academia, electrochemistry and catalysis scientists. This interest is due to environmental legislations for CO2 and other greenhouse gases emissions (United Nations Environment Programme and the World Trade Organization, 2009) that demand the use of high efficiency energy production systems. Such systems have great potential in the area of desalination technology (Kenet, 2003, Al-Hallaj et al., 2004, Singh, 2008, Wang et al. 2011, Jones, 2013). Fuel cells are characterised by high operation efficiency, which results in decreased fuel consumption, and low environmental impact. A fuel cell is a device that converts the chemical energy of a fuel directly into electricity through electrochemical reactions, with low waste heat (e.g. SOFC in Fig. 1). The first fuel cell was fabricated back in 1830's, and slow but steady progress has been made toward their commercialization since then

    Spin 3/2 Pentaquarks

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    We investigate the possible existence of the spin 3/2 pentaquark states using interpolating currents with K-N color-octet structure in the framework of QCD finite energy sum rule (FESR). We pay special attention to the convergence of the operator product expansion

    Magnetic moment of the pentaquark Θ+(1540)\Theta^+(1540) with light-cone QCD sum rules

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    In this article, we study the magnetic moment of the pentaquark state Θ+(1540) \Theta^+(1540) as diquark-diquark-antiquark ([ud][ud]sˉ[ud][ud]\bar{s}) state in the framework of the light-cone QCD sum rules approach. The numerical results indicate the magnetic moment of the pentaquark state Θ+(1540) \Theta^+(1540) is about μΘ+=(0.49±0.06)μN\mu_{\Theta^+}=-(0.49\pm 0.06)\mu_N.Comment: 10 pages, 1 figure. The main contents of this article is included in hep-ph/0503007, this article will not be submitted to a journal for publicatio

    J/Psi Propagation in Hadronic Matter

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    We study J/ψ\psi propagation in hot hadronic matter using a four-flavor chiral Lagrangian to model the dynamics and using QCD sum rules to model the finite size effects manifested in vertex interactions through form factors. Charmonium breakup due to scattering with light mesons is the primary impediment to continued propagation. Breakup rates introduce nontrivial temperature and momentum dependence into the J/ψ\psi spectral function.Comment: 6 Pages LaTeX, 3 postscript figures. Proceedings for Strangeness in Quark Matter 2003, Atlantic Beach, NC, March 12-17, 2003; minor corrections in version 2, to appear in J. Phys.

    Progress in the determination of the J/ψπJ/\psi-\pi cross section

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    Improving previous calculations, we compute the J/ψπcharmedmesonsJ/\psi \pi\to {charmed mesons} cross section using QCD sum rules. Our sum rules for the J/ψπDˉDJ/\psi \pi\to \bar{D} D^*, DDˉD \bar{D}^*, DˉD{\bar D}^* D^* and DˉD{\bar D} D hadronic matrix elements are constructed by using vaccum-pion correlation functions, and we work up to twist-4 in the soft-pion limit. Our results suggest that, using meson exchange models is perfectly acceptable, provided that they include form factors and that they respect chiral symmetry. After doing a thermal average we get 0.3\sim 0.3 mb at T=150\MeV.Comment: 22 pages, RevTeX4 including 7 figures in ps file

    Nonfactorizable contributions in B decays to charmonium: the case of BKhcB^- \to K^- h_c

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    Nonleptonic BB to charmonium decays generally show deviations from the factorization predictions. For example, the mode BKχc0B^- \to K^- \chi_{c0} has been experimentally observed with sizeable branching fraction while its factorized amplitude vanishes. We investigate the role of rescattering effects mediated by intermediate charmed meson production in this class of decay modes, and consider BKhcB^- \to K^- h_c with hch_c the JPC=1+J^{PC}=1^{+-} cˉc\bar c c meson. Using an effective lagrangian describing interactions of pairs of heavy-light QqˉQ{\bar q} mesons with a quarkonium state, we relate this mode to the analogous mode with χc0\chi_{c0} in the final state. We find B(BKhc){\cal B}(B^- \to K^- h_c) large enough to be measured at the BB factories, so that this decay mode could be used to study the poorly known hch_c.Comment: RevTex, 16 pages, 2 eps figure

    The Bethe ansatz as a matrix product ansatz

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    The Bethe ansatz in its several formulations is the common tool for the exact solution of one dimensional quantum Hamiltonians. This ansatz asserts that the several eigenfunctions of the Hamiltonians are given in terms of a sum of permutations of plane waves. We present results that induce us to expect that, alternatively, the eigenfunctions of all the exact integrable quantum chains can also be expressed by a matrix product ansatz. In this ansatz the several components of the eigenfunctions are obtained through the algebraic properties of properly defined matrices. This ansatz allows an unified formulation of several exact integrable Hamiltonians. We show how to formulate this ansatz for a huge family of quantum chains like the anisotropic Heisenberg model, Fateev-Zamolodchikov model, Izergin-Korepin model, tJt-J model, Hubbard model, etc.Comment: 4 pages and no figure

    Hadron yields and spectra in Au+Au collisions at the AGS

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    Inclusive double differential multiplicities and rapidity density distributions of hadrons are presented for 10.8 A GeV/c Au+Au collisions as measured at the AGS by the E877 collaboration. The results indicate that large amounts of stopping and collective transverse flow effects are present. The data are also compared to the results from the lighter Si+Al system.Comment: 12 pages, latex, 10 figures, submitted to Nuclear Physics A (Quark Matter 1996 Proceedings
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