24,420 research outputs found

    On the κ\kappa-Dirac Oscillator revisited

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    This Letter is based on the κ\kappa-Dirac equation, derived from the κ\kappa-Poincar\'{e}-Hopf algebra. It is shown that the κ\kappa-Dirac equation preserves parity while breaks charge conjugation and time reversal symmetries. Introducing the Dirac oscillator prescription, p→p−imωβr\mathbf{p}\to\mathbf{p}-im\omega\beta\mathbf{r}, in the κ\kappa-Dirac equation, one obtains the κ\kappa-Dirac oscillator. Using a decomposition in terms of spin angular functions, one achieves the deformed radial equations, with the associated deformed energy eigenvalues and eigenfunctions. The deformation parameter breaks the infinite degeneracy of the Dirac oscillator. In the case where ε=0\varepsilon=0, one recovers the energy eigenvalues and eigenfunctions of the Dirac oscillator.Comment: 5 pages, no figures, accepted for publication in Physics Letters

    REDUCED-SCALE STUDY OF LIQUID FUEL STORAGE TANK FIRE USING FIRE DYNAMICS SIMULATOR

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    Most of the accidents that occur in liquid fuel storage tank parks are caused by fire. This paper presents a numerical study using Large Eddy Simulation through Fire Dynamics Simulator (FDS) for the simulation of liquid fuel (ethanol) storage tanks at different scales (real-scale 1:1, and reduced- scales, 1:2, 1:4, 1:8). This paper proposes correlations for flame height, and temperature profile and radiative heat flux profile in the region adjacent to the tanks. Correlations have as inputs the diameters of the tanks in real- and reduced-scale, temperature profiles and radiative heat flux profiles for a reduced-scale tank simulation, and then provide as outputs flame height and temperature profiles and radiative heat flux profiles for the tank in real- scale. Percentage errors of the correlations found in this study are lower than 2.0% and 0.6% for the maximum radiative heat flux and maximum temperature, respectively

    Performing railway traffic vibration forecast using in situ vibration measurements

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    As international normalized methods for performing railway traffic vibration prediction are not available yet, the authors of this paper will analyze the feasibility and applicability of an in situ vibration measurement method in accordance with the guidelines establish in ISO 14837-1. The authors will present the achieved results of several vibration measurements, performed near the railways and the related transfer functions that will allow predicting the vibrations near different receiver locations

    Phantom Black Holes in Einstein-Maxwell-Dilaton Theory

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    We obtain the general static, spherically symmetric solution for the Einstein-Maxwell-dilaton system in four dimensions with a phantom coupling for the dilaton and/or the Maxwell field. This leads to new classes of black hole solutions, with single or multiple horizons. Using the geodesic equations, we analyse the corresponding Penrose diagrams revealing, in some cases, new causal structures.Comment: Latex file, 32 pages, 15 figures in eps format. Typo corrected in Eq. (3.18
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