flow and sediment transport processes are different and more complex in coarse-bed rivers than in sand-bed rivers. the main goal of the present study is to evaluate different modes of sediment transport using different hydrometric and hydraulic methods, and to address the major uncertainties. four river reaches were selected as representatives of coarse-bed rivers in the northwest of iran. a se...

Request oriented sensor networks have stricter requirements than conventional event-driven or periodic report models. Therefore, in this paper we propose a minimum energy data aggregation (MEDA), which meets the requirements for request oriented sensor networks by exploiting a low power real-time scheduler, ondemand time synchronization, variable response frame structure, and adaptive retransmi...

Deformation of the silo wall due to the single ball impact is modeled in ANSYS. The material in silo, as a Winkler bed, is replaced by spring-damper elements and the spring stiffness and damper coefficients are evaluated of the granular material and wall properties. The granular material deformation under the specified force is measured to evaluate the granular stiffness to be used for determin...

Downfall flows from different outlet hydraulic structures such as culverts and jetsthrowingtothe erodible downstream bed cause scour hole and changes in the downstream bed topography. Therefore,by performing some physical modeling tests on culvert jet flow under different angles, changes in the downstream bed topography under the effect of different parameters such as flow rate, depth of the ta...

In order to control aggregation phenomena in suspensions of nanoparticles, one often charges the particles electrically , e.g. by triboelectric charging. Stabilization of suspensions against aggregation of particles is an important issue, which may be realized by monopolar charging,where particles repel each other. Contrarily, bipolar charging may be used in coating processes, where smaller par...

The main challenge in wireless networks is to optimally use the confined radio resources to support data transfer. This holds for large-scale deployments as well as for small-scale test environments such as test-beds. We investigate two approaches to reduce the radio traffic in a test-bed, namely, filtering of unnecessary data and aggregation of redundant data. Both strategies exploit the fact ...

We present a method for aggregating information from an internal, machine representation and building a text structure that allows us to express aggregations in natural language. Features of the knowledge representation system, a semantic network, allow us to produce an initial aggregation based on domain information and the competing aggregate structures. In the £nal stages of realization, the...