Random drug testing of schoolchildren: A shot in the arm or a shot in the foot for drug prevention?
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The Effect of External and Internal Focus of Attention on Shot Put Skill
The purpose of the present study was to study the effect of attentional focus instructions on motor skills that requiring near to maximum force production, such as shot put skill. In this experiment, twenty eight right- handed girl students with little shot put experience were selected voluntarily. They divided to two groups (internal and external focus) based on their shot put scores in pre- t...
متن کاملModelling of Conventional and Severe Shot Peening Influence on Properties of High Carbon Steel via Artificial Neural Network
Shot peening (SP), as one of the severe plastic deformation (SPD) methods is employed for surface modification of the engineering components by improving the metallurgical and mechanical properties. Furthermore artificial neural network (ANN) has been widely used in different science and engineering problems for predicting and optimizing in the last decade. In the present study, effects of conv...
متن کاملFatigue Life of Repaired Welded Tubular Joints
In this study, the effect of repair on fatigue life of tubular joints is investigated. Six cracked specimens precedently subjected to fatigue loading undergone to weld repair. Two of those specimens were shot peened before primary fatigue loading. It is shown that repair gives rise to about 150% increase in fatigue life for original specimens while the increase of fatigue life for shot-peened ...
متن کاملStudy and Simulation of Shot peening Effect on Fatigue Life of a Powder Forged Connecting rod
Shot peening applies a residual compressive stress field (RCSF) on the surface of parts. It also shifts “crack nucleation sites” to sub-surface locations. A nondestructive method of measuring the stresses, Sin2ψ was utilized here and the stress values introduced to Ansys software. For this purpose, uniform stress in all directions was applied on the con rod. Loading on the rod in Ansys had thre...
متن کاملSide Effects of Shot Peening on Fatigue Crack Initiation Life
Shot peening beneficial effects on fatigue life of mechanical components are well known. However, there are some reports in the literature that indicate inappropriate shot peening parameters tend to reduce the fatigue life. It is therefore, the purpose of this study to find a logical quantitative justification for these observations. Using finite element method, a dynamic elastic-plastic simula...
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تاریخ انتشار 2005