Black holes/naked singularities in four-dimensional non-static space-time and the energy-momentum distributions

In this article, we discuss four dimensional non-static space-times in the background of de-Sitter and anti-de Sitter spaces with the matter-energy sources a stiff fluid, anisotropic fluid, and an electromagnetic field. Under various parameter conditions the solutions may represent models of naked singularity and/or black holes. Finally, the energy-momentum distributions using the complexes of Landau-Lifshitz, Einstein, Papapetrou, and M{\o}ller prescriptions, were evaluated.Comment: 18 pages, 6 figures. Accepted in EPJA. arXiv admin note: text overlap with arXiv:gr-qc/0309002 by other author

Multiscale approaches toward advanced lithium-ion battery: From nano to meso scale

“Battery performance and its degradation are determined by various aspects such as the transport of ions and electrons through heterogeneous internal structures composed of constituent particles, kinetic reactions at the interfaces, and a corresponding interplay between mechanical, chemical, and thermal responses. Further, modern battery materials require a variety of engineering processes such as coating, doping and mixing. As a result, in order to fully understand the behavior of the battery material and improve battery performance, it is necessary to understand and control the individual particle behavior and then connect it to the electrode. This study elucidated the physical phenomena associated with coating and grain boundaries and addressed the impact on cell-level performance. We also studied how to improve battery performance by changing the material and geometry of electrode components. The study was divided into three topics. First, it has been proved how an optimal layer thickness of CeO2 layer by ALD is better than too think or too thick layer in terms of li-ion diffusion, transition metal-ion dissolution and mechanical damage. Second, it was shown that how grain boundary can improve the cell performance significantly. Grain-boundary possesses different diffusion co-efficient than the bulk and thus the performance is different than the electrodes where no grains are considered. Also, it was shown how grain boundary has impact on stress generation for both cathode and anode particles. Finally, an attempt has been made to use Ni-VOx based nanofiber supported with carbon nanofiber to be used as an anode for advanced li-ion battery. Not only the process is simple but also the cell showed improved reversibility at a current rate of 100 mA/g”--Abstract, page iv