1,937 research outputs found
Cosmological Evolution of Interacting New Holographic Dark Energy in Non-flat Universe
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
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
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 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
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
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
Design and simulation of solar grid-connected charger for electric vehicles
© 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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