431 research outputs found
Emergence and Expansion of Cosmic Space in BIonic system
Recently, Padmanabhan [arXiv:1206.4916] argued that the expansion rate of the
universe can be thought of as the emergence of space as cosmic time progresses
and is related to the difference between the surface degrees of freedom on the
holographic horizon and the bulk degrees of freedom inside. The main question
arises as to what is origin of emergence of space in 4D universe? We answer to
this question in BIonic system. The BIon is a configuration in flat space of a
D-brane and a parallel anti-D-brane connected by a thin shell wormhole with
F-string charge. We propose a new model that allows all degrees of freedom
inside and outside the universe are controlled by the evolutions of BIon in
extra dimension and tend to degrees of freedom of black F-string in string
theory or black M2-brane in M theory.Comment: Published in Phys.Lett. B741 (2014) 92-9
The Finslerian wormhole models
We present models of wormhole under the Finslerian structure of spacetime.
This is a sequel of our previous work (Eur Phys J 75:564, 2015) where we
constructed a toy model for compact stars based on the Finslerian spacetime
geometry. In the present investigation, a wide variety of solutions are
obtained that explore wormhole geometry by considering different choices for
the form function and energy density. The solutions, like the previous work,
are revealed to be physically interesting and viable models for the explanation
of wormholes as far as the background theory and literature are concerned.Comment: 9 pages and 7 figue
Energy-momentum for a charged nonsingular black hole solution with a nonlinear mass function
The energy-momentum of a new four-dimensional, charged, spherically symmetric
and nonsingular black hole solution constructed in the context of general
relativity coupled to a theory of nonlinear electrodynamics is investigated,
whereby the nonlinear mass function is inspired by the probability density
function of the continuous logistic distribution. The energy and momentum
distributions are calculated by use of the Einstein, Landau-Lifshitz, Weinberg
and M{\o}ller energy-momentum complexes. In all these prescriptions it is found
that the energy distribution depends on the mass and the charge of the
black hole, an additional parameter coming from the gravitational
background considered, and on the radial coordinate . Further, the
Landau-Lifshitz and Weinberg prescriptions yield the same result for the
energy, while in all the aforesaid prescriptions all the momenta vanish. We
also focus on the study of the limiting behavior of the energy for different
values of the radial coordinate, the parameter , and the charge .
Finally, it is pointed out that for and all the
energy-momentum complexes yield the same expression for the energy distribution
as in the case of the Schwarzschild black hole solution.Comment: 20 pages, 4 figures, two of the figures changed, Discussion modified
accordingly, present version accepted for publication in AHE
Charged gravastars admitting conformal motion
We propose a new model of a {\it gravastar} admitting conformal motion. While
retaining the framework of the Mazur-Mottola model, the gravastar is assumed to
be internally charged, with an exterior defined by a Reissner-Nordstr{\"o}m
rather than a Schwarzschild line element. The solutions obtained involve (i)
the interior region, (ii) the shell, and (iii) the exterior region of the
sphere. Of these three cases the first case is of primary interest since the
total gravitational mass vanishes for vanishing charge and turns the total
gravitational mass into an {\it electromagnetic mass} under certain conditions.
This suggests that the interior de Sitter vacuum of a charged gravastar is
essentially an electromagnetic mass model that must generate the gravitational
mass. We have also analyzed various other aspects such as the stress energy
tensor in the thin shell and the entropy of the system.Comment: Minor addition, Accepted in Phys. Lett.
Study on Prevalence and Surgical Management of Haemorrhoid’s in a Tertiary Care Teaching Hospital in a Rural Area
Background: Haemorrhoids, which is also termed as piles characterized by the enlarged and bulged blood vessels surrounding the supporting tissues present in the anal canal of an individual. In the present study, an attempt has been made to find the prevalence of haemorrhoids and surgical management done in our geographical area.
Methods: The present study was retrospective, cross-sectional study from the period of 1st January 2013 to 31st December 2017. A total of 351 haemorrhoid’s patients were admitted in inpatient surgical ward during that period. The demographic details of all the patients were noted from the medical records.
Results: A total 219 (62%) patients were male and 132 (38%) were females. Most of the patients are predominantly adults above the age of 21 years. The post-operative stay in hospital is almost less than 10 days as it indicates that most of the patients were discharged without any complication.
Conclusions: The male patients are predominant compared to female patients. The surgical complications are less. The exact prevalence rate may be high as some patients may either undergo a self-treatment or native medicine treatmen
Determine the Electrical Energy Saving in Residential Sector of Iraq
The electricity consumption in residential complexes has severe impact on electricity production in Iraq because it currently constitutes more than 47% of the national energy consumption. Calculations have been made on the basis of predicted growth of residential energy consumption for the next 10 years which shows an increase from 64783 GWh in 2013 to 121606 GWh in 2023. This study analysis the data with a view to exploring the most suitable management systems for the residential electricity consumption in order to reduce the impact on the national energy production and promote the other sectors by saving energy consumption. It is worth mentioning that the household appliances and lighting devices which consume 34.95%, 13.55% and 13.20% of the total electrical energy consumptions in the residential sector respectively. Five scenarios have been adopted for maximizing the energy saving. It has been found that the fifth scenario is the best one
Physical properties of Tolman-Bayin solutions: some cases of static charged fluid spheres in general relativity
In this article, Einstein-Maxwell space-time has been considered in
connection to some of the astrophysical solutions as previously obtained by
Tolman (1939) and Bayin (1978). The effect of inclusion of charge into these
solutions has been investigated thoroughly and also the nature of fluid
pressure and mass density throughout the sphere have been discussed.
Mass-radius and mass-charge relations have been derived for various cases of
the charged matter distribution. Two cases are obtained where perfect fluid
with positive pressures give rise to electromagnetic mass models such that
gravitational mass is of purely electromagnetic origin.Comment: 15 pages, 12 figure
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