Sharif Digital Repository

The importance of having a rich repertoire of vocabulary at one’s disposal is evidently an undeniable fact for a successful communication. However, the best way to improve the lexical knowledge of the students is an issue that is still open to dispute. Considering this issue the present study focused on vocabulary learning strategies in L2 teaching. Actually, this study aimed at investigating three different methods of teaching new words to Iranian students in order to determine which one of the methods is more effective in terms of immediate and delayed retention. So the researchers strived to examine the question of how two different mnemonic devices, i.e., the Keyword method and the... 

The main purpose of the current study is to control the boundary layer of the flow passing over the wing and the lift force enhancement. In this research has been tried to introduce a new generation of passive flow control and use bumpy surface structures to control the separated flow and increase the aerodynamic efficiency. Therefore, the wing with the hawk bird’s airfoil section has been designated. Then, assuming a viscous, incompressible flow and a low Reynolds number range (about 2 × 105), the flow formation and boundary layer development on this wing has been investigated. Subsequently, bump structures have been settled on the upper surface of this wing. The numerical simulations have...