1. introduction the analysis of drainage networks is a powerful tool to detect recent tectonic activity and uplift, as river channels are very sensitive to changes in the parameters that control their shapes and. climate changes, tectonics and lithology affect river equilibrium conditions and hence, river geometry. a river is in dynamic equilibrium when erosion keeps pace with sedimentation and...

channel flows have three components of velocity, 1component in flow direction and 2components in spanwise of channel. because of heterogeneity of velocity undulations, in the channel section the vortices are formed that are nominated “secondary current cells”. these cells cause the lateral shear stress in the channel walls and introduce the erosion and scour of the channel walls. heterogeneity ...

Due to geographic and climatic conditions in mountainous northwest area, Roads in these areas are often covered with snow, ice and mud. Hence Transportation of equipment and soldiers encounter hardship and difficulties in rural area and specially outposts. To solve these problems, it is needed to fabricate portable roadway or traction mats. These high strength mats cover surface of roads and ar...

In this paper, collapse behavior of simple and reinforced thin-walled channel- section beams, subjected to three- point bending, is investigated. Many simple channel- section beams of different geometry and some reinforced ones were tested, and their strengths after collapse were obtained thoroughly. Since the available theories in this area are complicated and little attention has been paid to...

To simulate a new economical architecture for PEM fuel cell and investigate the effectiveness of the introduced structure on the performance, computational fluid dynamics (CFD) code is used to solve the equations for a single domain of the cell namely: the flow field, the mass conservation, the energy conservation, the species transport, and the electric/ionic fields under the assumptions of st...

We study the effect of channel geometry on the potential barrier encountered by ions as they permeate the acetylcholine receptor channel. Among the various channel geometries which have been used to represent the acetylcholine receptor channel include the cylinder and the toroidal catenary. The main reasons for those choices appear to be the facilitation of separation of the Poisson equation, r...

In this paper, collapse behavior of simple and reinforced thin-walled channel- section beams, subjected to three- point bending, is investigated. Many simple channel- section beams of different geometry and some reinforced ones were tested, and their strengths after collapse were obtained thoroughly. Since the available theories in this area are complicated and little attention has been paid to...