The problem of expansion of a dilute granular gas consisting of smooth, inelastic hard spheres into vacuum was investigated by three different methods: both (1) analytical and (2) computational (CFD) treatments of a hydrodynamic model, and (3) by Discrete Element Method (DEM) simulation. Furthermore, the systems were followed for long times, over which the granular kinetic energy decreases by s...

Computer aided design and computer aided modeling tools are becoming increasingly important in the design and performance evaluation of communication systems. In this work, we report on the computer simulation modeling study of terrestrial digital microwave radio transmission, using Block Oriented System Simulator package (BOSS). The work concentrates on semi-analytical error rate evaluation in...

for an indoor non-directed line of sight optical wireless communication (nlos-owc) system we investigate the optimized lambertian order (olo) of light-emitting diodes (leds). we firstly derive an expression for the olo from a conventional lambertian led model. then, we analyze the indoor multi-cell nlos-owc channel characteristics including the optical power distribution and the multipath time ...

Upgrading the voltage level of a transmission line is named as one solution to increase the transmitted power. This paper introduces the results of a research project in which the upgrade of Saravan-Sooran double circuit transmission system from 63 kV to 230 kV is studied. In this context, the towers remain in their current locations, where the new structure of towers and insulators as well as ...

an attempt is made for the first time to solve the quadratic and cubic model of magneto hydrodynamic poiseuille flow of phan-thein-tanner (ptt). series solution of magneto hydrodynamic (mhd) flow is developed by using homotopy perturbation method (hpm). results are presented graphically and the effects of non-dimensional parameters on the flow field are analyzed. the results obtained reveals ma...

Nowadays, the application of floating breakwaters in small or recreational harbors has found more popularity. These types of breakwaters are more flexible in terms of design, configuration and especially installation compared with fixed breakwaters. In the current study, the performance of floating breakwater (FBs) under regular waves was studied using the physical modeling method. For the mode...

arch dams are generally built in cantilvever monoliths. vertical contraction joints between monoliths control the stresses due to concrete shrinkage and temperature variations. past studies in earthquake safety evaluation of the system often show the tensile fracture and local nonlinear deformation of joints. in this paper, some nonlinear joint element constitutive models are presented to exami...

We have studied the collective plasma excitations of a two-dimensional electron gas with an arbitrary lateral charge-density modulation. The dynamics is formulated using a previously developed hydrodynamic theory based on the Thomas-Fermi-Dirac-von Weizsäcker approximation. In this approach, both the equilibrium and dynamical properties of the periodically modulated electron gas are treated in ...

In this paper, a model for hybrid transmission expansion planning (TEP) and reactive power planning (RPP) considering demand response (DR) model has been presented. In this study RPP considered by TEP for its effects on lines capacity and reduction of system expansion costs. On the other hand the expansion of the transmission system is an important subject, especially dealing with the new i...