Dynamics of Charged Bulk Viscous Collapsing Cylindrical Source With Heat Flux

In this paper, we have explored the effects of dissipation on the dynamics of charged bulk viscous collapsing cylindrical source which allows the out follow of heat flux in the form of radiations. Misner-Sharp formulism has been implemented to drive the dynamical equation in term of proper time and radial derivatives. We have investigated the effects of charge and bulk viscosity on the dynamics of collapsing cylinder. To determine the effects of radial heat flux, we have formulated the heat transport equations in the context of M$\ddot{u}$ller-Israel-Stewart theory by assuming that thermodynamics viscous/heat coupling coefficients can be neglected within some approximations. In our discussion, we have introduced the viscosity by the standard (non-casual) thermodynamics approach. The dynamical equations have been coupled with the heat transport equation equation, the consequences of resulting coupled heat equation have been analyzed in detail.Comment: 17 Pages, no figur

Effects of Electromagnetic Field on Gravitational Collapse

In this paper, the effect of electromagnetic field has been investigated on the spherically symmetric collapse with the perfect fluid in the presence of positive cosmological constant. Junction conditions between the static exterior and non-static interior spherically symmetric spacetimes are discussed. We study the apparent horizons and their physical significance. It is found that electromagnetic field reduces the bound of cosmological constant by reducing the pressure and hence collapsing process is faster as compared to the perfect fluid case. This work gives the generalization of the perfect fluid case to the charged perfect fluid. Results for the perfect fluid case are recovered.Comment: 17 pages, accepted for publication in Mod. Phys. Lett

Higher Dimensional Inhomogeneous Perfect Fluid Collapse in \emph{f(R)} Gravity

This paper is about the $n+2$-dimensional gravitational contraction of inhomogeneous fluid without heat flux in the framework of $f(R)$ metric theory of gravity. Matching conditions for two regions of a star has been derived by using the Darmois junction conditions. For the analytic solution of equations of motion in modified $f(R)$ theory of gravity, we have taken scalar curvature as constant. Hence final result of gravitational collapse in this frame work is the existence of black hole and cosmological horizons, both of these form earlier than singularity. It has been shown that constant curvature term $f(R_{0})$ ($R_0$ is constant scalar curvature) slows down the collapsing process.Comment: 17 Pages, to appear in European Physical Journal

Evaluating the Success of Malaysia’s Exchange Controls (1998-99)

The paper evaluates in depth, the exchange control measures imposed by Malaysia in September-1998. Controls are evaluated using three alternative benchmarks—Malaysia vs. itself (pre-controls), vs. ex-ante forecasts of Malaysia for the year-1999, and Malaysia vs. the other affected East Asian economies. The comparisons suggest that controls were effective in turning some key variables around, especially the stock market index, and also enabled Malaysia to incur fewer social costs vis-à-vis the other crisis-economies. Finally, a GARCH measure of Malaysia’s interest-rate and stock-market volatility is obtained and the impact of controls on volatility studied. Evidence was found of volatility responding differentially to the Russian crisis (before controls) and the Brazilian crisis (after controls), indicating that controls helped insulate Malaysia from developments in global financial markets. Overall the paper confirms the necessity of LDCs retaining the capital controls option in the absence of material efforts to reform the international financial architecture and the inadequacy of conventional policy tools to effectively deal with present-day capital flows.

The 43GHz SiO maser in the circumstellar envelope of the AGB star R Cassiopeiae

We present multi-epoch, total intensity, high-resolution images of 43GHz, v=1, J=1-0 SiO maser emission toward the Mira variable R Cas. In total we have 23 epochs of data for R Cas at approximate monthly intervals over an optical pulsation phase range from 0.158 to 1.78. These maps show a ring-like distribution of the maser features in a shell, which is assumed to be centred on the star at a radius of 1.6 to 2.3 times the stellar radii. It is clear from these images that the maser emission is significantly extended around the star. At some epochs a faint outer arc can be seen at 2.2 stellar radii. The intensity of the emission waxes and wanes during the stellar phase. Some maser features are seen infalling as well as outflowing. We have made initial comparisons of our data with models by Gray et. al. (2009).Comment: 12 pages, 14 figure

Phantom Energy Accretion by Stringy Charged Black Hole

We investigate the dynamical behavior of phantom energy near stringy magnetically charged black hole. For this purpose, we derive equations of motion for steady-state spherically symmetric flow of phantom energy onto the stringy magnetically charged black hole. It is found that phantom energy accreting onto black hole decreases its mass. Further, the location of critical points of accretion is explored, which yields mass to charge ratio. This ratio implies that accretion process cannot transform a black hole into an extremal black hole or a naked singularity, hence cosmic censorship hypothesis remains valid here.Comment: 7 pages, no figur

Ulam Stability for Partial Fractional Differential Inclusions via Picard Operators Theory

In the present paper, we investigate, using the Picard operator technique, some existence and Ulam type stability results for the Darboux problem associated to some partial fractional order differential inclusions