in order to present a quantitative indicator for the onset of instability, in this paper, the critical points of a stratified gravitational flow on a slope are found and analyzed. these points are obtained by means of the solution of the two-dimensional navier-stokes equations via the standard arakawa-c finite-difference method. results show that in the marginal richardson numbers, the critical...

The main purpose of this research is portfolio optimization in Tehran securities exchange using the black hole algorithm and the Gravitational Research algorithm. We also propose an algorithm named Hybrid Algorithm which combines the two algorithms above to cover the weaknesses of these two algorithms. Finally we compare the results with the Markowitz model and choose the optimal algorithm.<br ...

Tectonic inversion of passive margins is a common but poorly documented process preceding subduction inception. We perform here comprehensive land-sea experimental modeling this key by reproducing the morphotectonic and sedimentary evolution central Algerian margin over last 6 Myr. Our approach based on scaled analog models integrating interactions between crustal shortening surface processes, ...

gravitational search algorithm (gsa) is one of the newest swarm based optimization algorithms, which has been inspired by the newtonian laws of gravity and motion. gsa has empirically shown to be an efficient and robust stochastic search algorithm. since introducing gsa a convergence analysis of this algorithm has not yet been developed. this paper introduces the first attempt to a formal conve...

Here, we investigate the possible optical anisotropy of vacuum due to gravitational field. In doing this, we provide sufficient evidence from direct coordinate integration of the null-geodesic equations obtained from the Lagrangian method, as well as ray-tracing equations obtained from the Plebanski’s equivalent medium theory. All calculations are done for the Schwarzschild geometry, which resu...

An important problem in the study of microparticles in the marine environment, suspended in the water column or deposited as sediment on the ocean bottom, is the determination of provenance of the microparticles-where did they come from and by what processes were they transported to the sampling location? Two techniques of possible interest to those concerned with tracing the origins and disper...