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    To PB or not PB: making wikis work for your library

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    Library staff at Leeds Metropolitan University have recently launched a wiki to help them with the organisation of the information they need for their day-to-day enquiry and circulation duties. Here we outline the development of the project and the reasons behind choosing a wiki as the best format for this information

    Fractal Droplets in Two Dimensional Spin Glasses

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    The two-dimensional Edwards-Anderson model with Gaussian bond distribution is investigated at T=0 with a numerical method. Droplet excitations are directly observed. It turns out that the averaged volume of droplets is proportional to l^D with D = 1.80(2) where l is the spanning length of droplets, revealing their fractal nature. The exponent characterizing the l dependence of the droplet excitation energy is estimated to be -0.42(4), clearly different from the stiffness exponent for domain wall excitations.Comment: 4 pages 4 figure

    Energy Correlations In Random Transverse Field Ising Spin Chains

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    The end-to-end energy - energy correlations of random transverse-field quantum Ising spin chains are computed using a generalization of an asymptotically exact real-space renormalization group introduced previously. Away from the critical point, the average energy - energy correlations decay exponentially with a correlation length that is the same as that of the spin - spin correlations. The typical correlations, however, decay exponentially with a characteristic length proportional to the square root of the primary correlation length. At the quantum critical point, the average correlations decay sub-exponentially as CLˉ∌e−const⋅L1/3\bar{C_{L}}\sim e^{-const\cdot L^{1/3}}, whereas the typical correlations decay faster, as ∌e−KL\sim e^{-K\sqrt{L}}, with KK a random variable with a universal distribution. The critical energy-energy correlations behave very similarly to the smallest gap, computed previously; this is explained in terms of the RG flow and the excitation structure of the chain. In order to obtain the energy correlations, an extension of the previously used methods was needed; here this was carried out via RG transformations that involve a sequence of unitary transformations.Comment: Submitted to Phys. Rev.

    Laser Schlieren and ultraviolet diagnostics of rocket combustion

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    A low pressure oxygen/hydrogen turbine drive combustor hot-fire test series was conducted on the Turbine Drive Combustor Technology Program. The first objective was to gather data on an axisymmetric combustion system to support anchoring of a new combustion/fluid dynamics computer code under development on the same contract. The second objective was to gain insight into low mixture ratio combustion characteristics of coaxial injector elements
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