1,387 research outputs found
Thermodynamical description of interacting entropy-corrected new agegraphic dark energy
To explain the accelerating universe driven by dark energy, a so-called
"entropy-corrected new agegraphic dark energy" (ECNADE), was recently proposed
with the help of quantum corrections to the entropy-area relation in the
framework of loop quantum cosmology. Using this definition, we study its
thermodynamical features including entropy and energy conservation. We discuss
the thermodynamical interpretation of the interaction between ECNADE and dark
matter in a non-flat universe bounded by the apparent horizon. We obtain a
relation between the interaction term of the dark components and thermal
fluctuation.Comment: 8 pages, version accepted for publication in Europhysics Letters
(2011
Attractor Solutions in f(T) Cosmology
In this paper, we explore the cosmological implications of interacting dark
energy model in a torsion based gravity namely . Assuming dark energy
interacts with dark matter and radiation components, we examine the stability
of this model by choosing different forms of interaction terms. We consider
three different forms of dark energy: cosmological constant, quintessence and
phantom energy. We then obtain several attractor solutions for each dark energy
model interacting with other components. This model successfully explains the
coincidence problem via the interacting dark energy scenario.Comment: 10 pages, 23 figures, version accepted for publication in European
Physical Journal C (2012
Can a wormhole generate electromagnetic field?
We have considered the possibility of a slowly rotating wormhole surrounded
by a cloud of charged particles. Due to slow rotation of the wormhole, the
charged particles are dragged thereby producing an electromagnetic field. We
have determined the strength of this electromagnetic field and the
corresponding flux of radiation.Comment: 9 pages, typos fixe
Solvable K-essence Cosmologies and Modified Chaplygin Gas Unified Models of Dark Energy and Dark Matter
This paper is devoted to the investigation of modified Chaplygin gas model in
the context of solvable k-essence cosmologies. For this purpose, we construct
equations of state parameter of this model for some particular values of the
parameter . The graphical behavior of these equations are also discussed by
using power law form of potential. The relationship between k-essence and
modified Chaplygin gas model shows viable results in the dark energy scenario.
We conclude that the universe behaves as a cosmological constant, quintessence
phase or phantom phase depending upon .Comment: 14 pages, 6 figure
Possibility of cyclic Turnarounds In Brane-world Scenario: Phantom Energy Accretion onto Black Holes and its consequences
A universe described by braneworlds is studied in a cyclic scenario. As
expected such an oscillating universe will undergo turnarounds, whenever the
phantom energy density reaches a critical value from either side. It is found
that a universe described by RSII brane model will readily undergo oscillations
if, either the brane tension, \lambda, or the bulk cosmological constant,
\Lambda_{4}, is negative. The DGP brane model does not readily undergo cyclic
turnarounds. Hence for this model a modified equation is proposed to
incorporate the cyclic nature. It is found that there is always a remanent mass
of a black hole at the verge of a turnaround. Hence contrary to known results
in literature, it is found that the destruction of black holes at the
turnaround is completely out of question. Finally to alleviate, if not solve,
the problem posed by the black holes, it is argued that the remanent masses of
the black holes do not act as a serious defect of the model because of Hawking
evaporation.Comment: 10 pages, 2 figures; International Journal of Theoretical Physics
(2012
Statefinder Parameter for Varying G in Three Fluid System
In this work, we have considered variable G in flat FRW universe filled with
the mixture of dark energy, dark matter and radiation. If there is no
interaction between the three fluids, the deceleration parameter and
statefinder parameters have been calculated in terms of dimensionless density
parameters which can be fixed by observational data. Also the interaction
between three fluids has been analyzed due to constant . The statefinder
parameters also calculated in two cases: pressure is constant and pressure is
variable.Comment: 5 pages, Accepted for publication in "Astrophysics and Space Science
Design Concepts and Process Analysis for Transmuter Fuel Manufacturing: Quarterly Progress Report #2
This report discusses mainly the fabrication of inert matrix fuels. There are three fabrication routes to obtain inert matrix fuels (IMF). IMF is a dispersion-type fuel in which the actinide phase is distributed as a separate phase in a so called inert matrix. This concept has evolved as one of the most promising in the field of transmutation. The following section discusses each manufacturing route aside
Statefinder Parameters for Different Dark Energy Models with Variable G Correction in Kaluza-Klein Cosmology
In this work, we have calculated the deceleration parameter, statefinder
parameters and EoS parameters for different dark energy models with variable
correction in homogeneous, isotropic and non-flat universe for Kaluza-Klein
Cosmology. The statefinder parameters have been obtained in terms of some
observable parameters like dimensionless density parameter, EoS parameter and
Hubble parameter for holographic dark energy, new agegraphic dark energy and
generalized Chaplygin gas models.Comment: 9 pages, no figure, accepted for publication in IJTP. arXiv admin
note: text overlap with arXiv:1104.2366 by other author
Potentiality of the Usage of Compressed Natural Gas for Competitiveness in Service Delivery Industries
. With the rising costs of gasoline, many vehicle owners are looking for alternatives of it. Compressed natural gas (CNG) has been tested for this very purpose in some countries and found as a better alternative so far. CNG comes from country's natural resources and it is clean and less costly to use. This paper is mainly an analysis of the potential benefits of using natural gas as a transportation fuel by the service delivery industries. It will examine CNG's potential contribution in reducing delivery and vehicle maintenance cost, saving money in the long run projects, improving fuel efficiency, enhancing physical safety and assuring environment friendly emissions of carbon monoxide or reactive gases for the service delivery industries
Financing Small and Medium Enterprises in Bangladesh – Issues and Challenges
. Now-a-days, Small and Medium Enterprises (SMEs) have become an important sector that is supposed to play a pivotal role in boosting the economy of Bangladesh. But, SME financing is still facing some remarkable challenges that limit its potential success in contributing to the economy. Lots of thinking has contributed to the initiation and development of SMEs in Bangladesh. Now is the time to identify the challenges and making adjustments to the initial thinking. This paper is, therefore, an attempt to analyze various issues and challenges of financing this particular sector and find some worthy ways out to overcome these challenges. It will also survey various literatures and reports on the concerned field and recommend supporting actions to help this highly prospective industrial sector operate in a fully yielding manner
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