flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...

due to lack of knowledge management system in the organization of technical and vocational university of iran (tvuni) and losing good employees because of retirement and substitution causes huge amount of costs to replace the similar expertise. there is no any suitable system in the tvuni to store, to document, and to distribute knowledge. based on the university’s features such as it has diffe...

target tracking is the tracking of an object in an image sequence. target tracking in image sequence consists of two different parts: 1- moving target detection 2- tracking of moving target. in some of the tracking algorithms these two parts are combined as a single algorithm. the main goal in this thesis is to provide a new framework for effective tracking of different kinds of moving target...

the purpose of this study was to investigate the effect of task repetition on accuracy of iranian efl learners ’speaking ability. in order to achieve this purpose, a null hypothesis was developed: there is no statistically significant difference between accuracy speaking ability in iranian efl learners by use of task repetition. ; of course i should mention that, beside this null hypothesis, an...

abstract i the purpose of this study was to launch a thorough investigation concerning the possibility of differing orientations to the writing proficiency construct by native and non-native english speaking teacher raters. it mainly revolved around the international english language testing system (ielts) that is widely administered and employed as a measure of general proficiency in englis...

run-out-table (rot) is located between last finishing stand and down coiler in a hot strip mill. as the hot steel strip passes from rot, water jets impact on it from top and bottom and strip temperature decreases approximately from 800-950 °c to 500-750°c. the temperature history that strip experience while passing through rot affects significantly the metallurgical and mechanical properties, s...

the study of air infiltration into the buildings is important from several perspectives that may be noted to energy and design of hvac systems, indoor air quality and thermal comfort and design of smoke control systems. given the importance of this issue, an experimental and numerical study of air infiltration through conventional doors and windows has been explored in iran. to this end, at fir...

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

this study investigated the effects of manipulating the cognitive complexity of tasks along +/- few elements and the time limits on l2 learners writing performance. to conduct the study, 60 iranian efl learners with two levels of proficiency, low and high intermediate, were selected and assigned to three groups based on the time devoted to task completion. the participants performed both a simp...