non-destructive ultrasonic testing is one of the methods utilized to evaluate quality of agricultural produce. transducers used in this method are made for basically industrial applications. since ultrasonic attenuation of waves in agricultural produce is very high, industrial transducers cannot be used in agriculture and needs to be modified. this is done with horns that concentrate energy on ...

background: the rapid growth of computer games, has taken a major part of teenagers leisure time. the improper and overuse of these games, can be considered as physical, mental and social threats. the goal of this study was to determine the relationship between playing computer games and students’ aggression and academic progress.   methods: in this cross- sectional study, 292 students in grade...

the purpose of this study is to investigate the relationship between computer experience, social skills and blind students' self-efficacy in the secondary level through tehran city schools, so 129 students were selected among tehran blind schools with accessible sampling (36 females and 93 males). the results of regression analysis showed that computer experience and social skills can pred...

in this paper, a discrete event simulation model of iranian railway system is used for analyzing performance of the system in freight sector. the model analysis shows more sensitivity of the system on loading and unloading facilities than on number of wagons and locomotives. system optimization through simulation optimization technique, shows that more than 4% of all wagons available in the net...

Detailed investigation on biomechanics of a complex structure such as the human lumbar spine requires the use of advanced computer-based technique for both the geometrical reconstruction and the stress analysis. In the present study, the computer-assisted tomography (CAT) and finite element method (FEM) are merged to perform detailed three dimensional nonlinear analysis of the human ligamentous...