1,270 research outputs found

    Applying uncertainty considerations to energy conservation equations

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    When applying computer simulation tools in practice uncertainties abound, for example in material properties and boundary conditions. To facilitate the quantification of the effects of uncertainties, the differential, factorial and Monte Carlo methods have been implemented within a simulation tool, ESP-r. These methods require multiple simulations to extract statistical measures of model uncertainty. An alternative approach is to embed uncertainty considerations within the simulation tool's algorithms. The principle advantages of this approach are that the uncertainty is quantified at all times and therefore requires only a single simulation. Coupled with this, it is possible to take control action based on the prevailing effects of uncertainties. This paper details the mathematical techniques required to integrate uncertainty considerations within the energy conservation equations when applied to the simulation of buildings. A comparison is made between the use of this novel approach and traditional mechanisms of assessing uncertainty

    A computational method for the coupled solution of reaction–diffusion equations on evolving domains and manifolds: application to a model of cell migration and chemotaxis

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    In this paper, we devise a moving mesh finite element method for the approximate solution of coupled bulk–surface reaction–diffusion equations on an evolving two dimensional domain. Fundamental to the success of the method is the robust generation of bulk and surface meshes. For this purpose, we use a novel moving mesh partial differential equation (MMPDE) approach. The developed method is applied to model problems with known analytical solutions; these experiments indicate second-order spatial and temporal accuracy. Coupled bulk–surface problems occur frequently in many areas; in particular, in the modelling of eukaryotic cell migration and chemotaxis. We apply the method to a model of the two-way interaction of a migrating cell in a chemotactic field, where the bulk region corresponds to the extracellular region and the surface to the cell membrane

    A computational method for the coupled solution of reaction-diffusion equations on evolving domains and manifolds : application to a model of cell migration and chemotaxis

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    In this paper, we devise a moving mesh finite element method for the approximate solution of coupled bulk-surface reaction-diffusion equations on an evolving two dimensional domain. Fundamental to the success of the method is the robust generation of bulk and surface meshes. For this purpose, we use a novel moving mesh partial differential equation (MMPDE) approach. The developed method is applied to model problems with known analytical solutions; these experiments indicate second-order spatial and temporal accuracy. Coupled bulk-surface problems occur frequently in many areas; in particular, in the modelling of eukaryotic cell migration and chemotaxis. We apply the method to a model of the two-way interaction of a migrating cell in a chemotactic field, where the bulk region corresponds to the extracellular region and the surface to the cell membrane

    Experimental and numerical study of local mean age of air

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    This paper presents the results from the experimental and numerical study of a room with mixing ventilation, focused on the local mean age of air (LMA). The measurements were performed using the tracer gas concentration decay method. The numerical predictions were obtained from the computational fluid dynamics (CFD) module of the latest version of the ESP-r software

    Two-Dimensional Vortex Lattice Melting

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    We report on a Monte-Carlo study of two-dimensional Ginzburg-Landau superconductors in a magnetic field which finds clear evidence for a first-order phase transition characterized by broken translational symmetry of the superfluid density. A key aspect of our study is the introduction of a quantity proportional to the Fourier transform of the superfluid density which can be sampled efficiently in Landau gauge Monte-Carlo simulations and which satisfies a useful sum rule. We estimate the latent heat per vortex of the melting transition to be ∼0.38kBTM\sim 0.38 k_B T_M where TMT_M is the melting temperature.Comment: 10 pages (4 figures available on request), RevTex 3.0, IUCM93-00

    Integral Representations of the Macdonald Symmetric Functions

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    Multiple-integral representations of the (skew-)Macdonald symmetric functions are obtained. Some bosonization schemes for the integral representations are also constructed.Comment: LaTex 21page

    Measurement of K^+ \to \pi^0 \mu^+ \nu \gamma decay using stopped kaons

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    The K^+ \to \pi^0 \mu^+ \nu \gamma (Kμ3γK_{\mu 3 \gamma}) decay has been measured with stopped positive kaons at the KEK 12 GeV proton synchrotron. A Kμ3γK_{\mu 3 \gamma} sample containing 125 events was obtained. The partial branching ratio Br(Kμ3γ,Eγ>30MeV,θμ+γ>20∘)Br(K_{\mu 3 \gamma}, E_{\gamma}>30 {\rm MeV}, \theta_{\mu^+ \gamma}>20^{\circ}) was found to be [2.4±0.5(stat)±0.6(syst)]×10−5[2.4 \pm 0.5(stat) \pm 0.6(syst)]\times 10^{-5}, which is in good agreement with theoretical predictions.Comment: 12 pages, 3 figures, to be published in Physics Letters
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