Validity of the Generalized Second Law of Thermodynamics of the Universe Bounded by the Event Horizon in Brane Scenario

In this paper, we examine the validity of the generalized second law of thermodynamics (GSLT) of the universe bounded by the event horizon in brane-world gravity. Here we consider homogeneous and isotropic model of the universe filled with perfect fluid in one case and in another case holographic dark energy model of the universe has been considered. The conclusions are presented point wise.Comment: 8 pages, the paper has been accepted in EPJC for publication. Conclusion has been modified an some references have been adde

Symmetric and anti-symmetric Landau parameters and magnetic properties of dense quark matter

We calculate the dimensionless Fermi liquid parameters (FLPs), $F_{0,1}^{sym}$ and $F_{0,1}^{asym}$, for spin asymmetric dense quark matter. In general, the FLPs are infrared divergent due to the exchange of massless gluons. To remove such divergences, the Hard Density Loop (HDL) corrected gluon propagator is used. The FLPs so determined are then invoked to calculate magnetic properties such as magnetization $\langle M\rangle$ and magnetic susceptibility $\chi_M$ of spin polarized quark matter. Finally, we investigate the possibility of magnetic instability by studying the density dependence of $\langle M\rangle$ and $\chi_M$.Comment: 14 pages, 5 figures, abstract and introduction modifified. Published in Phys. Rev. C. 81, 054906 (2010

FRW Universe in Ho\~rava Gravity

Recently, a field theoretic model for a UV complete theory of gravity has been proposed by Ho\~{r}ava. This theory is a non-relativistic renormalizable gravity theory which coincides with Einstein's general relativity at large distances. Subsequently L\"{u} et al have formulated the modified Friedmann equations and have presented a solution in vacuum. In the present work, we rewrite the modified FRW equations in the form of usual FRW equations in Einstein gravity and consequences has been analyzed. Also the thermodynamics of the FRW universe has been studied

Excess power circulation in distribution networks containing distributed energy resources

The presence of large number of single-phase distributed energy resources (DERs) can cause severe power quality problems in distribution networks. The DERs can be installed in random locations. This may cause the generation in a particular phase exceeds the load demand in that phase. Therefore the excess power in that phase will be fed back to the transmission network. To avoid this problem, the paper proposes the use of distribution static compensator (DSTATCOM) that needs to be connected at the first bus following a substation. When operated properly, the DSTATCOM can facilitate a set of balanced current flow from the substation, even when excess power is generated by DERs. The proposals are validated through extensive digital computer simulation studies using PSCAD and MATLAB

Scalar-Tensor Theory of Gravity and Generalized Second Law of Thermodynamics on the Event Horizon

In blackhole physics, the second law of thermodynamics is generally valid whether the blackhole is a static or a non-static one. Considering the universe as a thermodynamical system the second law of blackhole dynamics extends to the non-negativity of the sum of the entropy of the matter and the horizon, known as generalized second law of thermodynamics(GSLT). Here, we have assumed the universe to be bounded by the event-horizon or filled with perfect fluid and holographic dark energy in two cases. Thus considering entropy to be an arbitrary function of the area of the event-horizon, we have tried to find the conditions and the restrictions over the scalar field and equation of state for the validity of the GSLT and both in quintessence-era and in phantom-era in scalar tensor theory.Comment: 8 page

ρ\rho-ω\omega mixing and spin dependent CSV potential

We construct the charge symmetry violating (CSV) nucleon-nucleon potential induced by the $\rho^0$-\o mixing due to the neutron-proton mass difference driven by the $NN$ loop. Analytical expression for for the two-body CSV potential is presented containing both the central and non- central $NN$ interaction. We show that the $\rho$$NN$ tensor interaction can significantly enhance the charge symmetry violating $NN$ interaction even if momentum dependent off-shell $\rho^0$-$\omega$ mixing amplitude is considered. It is also shown that the inclusion of form factors removes the divergence arising out of the contact interaction. Consequently, we see that the precise size of the computed scattering length difference depends on how the short range aspects of the CSV potential are treated.Comment: Accepted for publication in Phys. Rev.

Stopping power of hot QCD plasma

The partonic energy loss has been calculated taking both the hard and soft contributions for all the $2 \to 2$ processes, revealing the importance of the individual channels. Cancellation of the intermediate separation scale has been exhibited. Subtleties related to the identical final state partons have properly been taken into account. The estimated collisional loss is compared with its radiative counter part. We show that there exists a critical energy ($E_c$) below which the collisional loss is more than its radiative counterpart. In addition, we present closed form formulas for both the collision probabilities and the stopping power ($dE/dx$)Comment: revised version, section added, 9pages with 5 figure

The effects of water and microstructure on the performance of polymer electrolyte fuel cells

n this paper, we present a comprehensive non-isothermal, one-dimensional model of the cathode side of a Polymer Electrolyte Fuel Cell. We explicitly include the catalyst layer, gas diffusion layer and the membrane. The catalyst layer and gas diffusion layer are characterized by several measurable microstructural parameters. We model all three phases of water, with a view to capturing the effect that each has on the performance of the cell. A comparison with experiment is presented, demonstrating excellent agreement, particularly with regard to the effects of water activity in the channels and how it impacts flooding and membrane hydration. We present several results pertaining to the effects of water on the current density (or cell voltage), demonstrating the role of micro-structure, liquid water removal from the channel, water activity, membrane and gas diffusion layer thickness and channel temperature. These results provide an indication of the changes that are required to achieve optimal performance through improved water management and MEA-component design. Moreover, with its level of detail, the model we develop forms an excellent basis for a multi-dimensional model of the entire membrane electrode assembly

A Motivating Exploration on Lunar Craters and Low-Energy Dynamics in the Earth -- Moon System

It is known that most of the craters on the surface of the Moon were created by the collision of minor bodies of the Solar System. Main Belt Asteroids, which can approach the terrestrial planets as a consequence of different types of resonance, are actually the main responsible for this phenomenon. Our aim is to investigate the impact distributions on the lunar surface that low-energy dynamics can provide. As a first approximation, we exploit the hyberbolic invariant manifolds associated with the central invariant manifold around the equilibrium point L_2 of the Earth - Moon system within the framework of the Circular Restricted Three - Body Problem. Taking transit trajectories at several energy levels, we look for orbits intersecting the surface of the Moon and we attempt to define a relationship between longitude and latitude of arrival and lunar craters density. Then, we add the gravitational effect of the Sun by considering the Bicircular Restricted Four - Body Problem. As further exploration, we assume an uniform density of impact on the lunar surface, looking for the regions in the Earth - Moon neighbourhood these colliding trajectories have to come from. It turns out that low-energy ejecta originated from high-energy impacts are also responsible of the phenomenon we are considering.Comment: The paper is being published in Celestial Mechanics and Dynamical Astronomy, vol. 107 (2010