1,937 research outputs found

    Cosmological Evolution of Interacting New Holographic Dark Energy in Non-flat Universe

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    We consider the interacting holographic dark energy with new infrared cutoff (involving Hubble parameter and its derivative) in non-flat universe. In this context, we obtain the equation of state parameter which evolutes the universe from vacuum dark energy region towards quintessence region for particular values of constant parameters. It is found that this model always remains unstable against small perturbations. Further, we establish the correspondence of this model having quintessential behavior with quintessence, tachyon, K-essence and dilaton scalar field models. The dynamics of scalar fields and potentials indicate accelerated expansion of the universe which is consistent with the current observations. Finally, we discuss the validity of the generalized second law of thermodynamics in this scenario.Comment: 21 pages, 13 figure

    Accretion onto Some Well-Known Regular Black Holes

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    In this work, we discuss the accretion onto static spherical symmetric regular black holes for specific choices of equation of state parameter. The underlying regular black holes are charged regular black hole using Fermi-Dirac Distribution, logistic distribution, nonlinear electrodynamics, respectively and Kehagias-Sftesos asymptotically flat regular black hole. We obtain the critical radius, critical speed and squared sound speed during the accretion process near the regular black holes. We also study the behavior of radial velocity, energy density and rate of change of mass for each regular black holes.Comment: 25 pages, 7 figures, Accepted for publication in Eur. Phys. J.

    Effects of Thermal Fluctuations on Non-minimal Regular Magnetic Black Hole

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    We analyze the effects of thermal fluctuations on a regular black hole (RBH) of non-minimal Einstein-Yang-Mill theory with gauge field of magnetic Wu-Yang type and a cosmological constant. We consider the logarithmic corrected entropy in order to analyze the thermal fluctuations corresponding to non-minimal RBH thermodynamics. In this scenario, we develop various important thermodynamical quantities such as entropy, pressure, specific heats, Gibb's free energy and Helmothz free energy. We investigate first law of thermodynamics in the presence of logarithmic corrected entropy and non-minimal RBH. We also discuss the stability of this RBH using various frameworks such as Îł\gamma factor (comprises of ratio of heat capacities), phase transition, grand canonical ensemble and canonical ensemble. It is observed that the non-minimal RBH becomes more globally and locally stable if we increase the value of cosmological constant.Comment: 20 pages, 5 figure

    Tidal Forces in Kiselev Black Hole

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    The aim of this paper is to examine the tidal forces occurred in Kiselev black hole surrounded by radiation and dust fluids. It is noted that radial and angular component of tidal force change the sign between event and Cauchy horizons. We solve the geodesic deviation equation for radially free falling bodies toward Kiselev black holes. We explain the geodesic deviation vector graphically and point out the location of event and Cauchy horizons in it for specific values of radiation and dust parameter.Comment: 20 pages, 10 figure

    Accreting Fluids onto Regular Black Holes Via Hamiltonian Approach

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    We investigate the accretion of test fluids onto regular black holes such as Kehagias-Sfetsos black hole and a regular black hole with Dagum Distribution Function. We analyze the accretion process when different test fluids are falling onto these regular black holes. The accreting fluid is being classified through equation of state according to features of regular black holes. The behavior of fluid flow and the existence of sonic points is being checked for these regular black holes. It is noted that three velocity depends on critical points and equation of state parameter on phase space.Comment: 25 pages; 10 Figure

    In Praise of Dialogue: Storytelling as a Means of Negotiated Diversity Management

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    Design and simulation of solar grid-connected charger for electric vehicles

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    © 2018 IEEE. Electric Vehicles (EV) are playing major role in decreasing carbon emissions. The major problem so far with the Electric Vehicles are overloading the Distribution Grids and availability of enough charging stations. The main objective of this research is to design and install a solar powered charging station for EVs in the UAE environment. This research aims to focus on the need for the shifting from the traditional gas and petrol vehicles to Electric vehicles in the UAE. Additionally, the project intends to ease the problem of the additional load that these EVs impose on the grid by powering the charging station from solar energy. This will help evolve the existing transport system of the UAE into a cleaner and greener system. The project is divided mainly into three important parts. First of all, the system components are designed to match with the ratings of available most common EVs. Then the system has been modelled in DIgSILENT Power factory for the simulation and validation of design. Finally, the results from calculations and simulations are described and compared
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