Gears are commonly used for transmitting power. They develop high stress concentration at the root and the point of contact. The repeated stressing on the fillets causes the fatigue failure of gear tooth. The main objective of this study is to add different shaped holes to reduce stress concentration. A finite element model of Spur gear with a segment of three teeth is considered for analysis a...

aim and background:   the main purpose of this study was to investigate effectiveness of mindfulness-based stress reduction (mbsr   ) on decreasing depression in patients with chronic low back pain. methods and materials:   the statistical population included patients with chronic low back pain who appointed the pain clinics in tehran. among whom 23 participants were enrolled with convenience s...

Droughtis oneof the most importantfactors limitingcrop productioninarid and semiaridregions, such as Iran.In order to study drought stress in four grain sorghum varieties (Kimia, Sepideh, KGS15 and KGS23), an experiment was laid in randomized complete block design with three replications in a split plot arrangement. Water treatments were considered the main plot at three levels: irrigation afte...

background : stress has been defined as a barrier to concentration, problem solving, decision making, and other necessary abilities for students' learning; it also has some symptoms and illnesses in the students such as depression and anxiety. in reviewing stress and its consequences, the methods of coping with stress in the method of response to it would be more important than the nature of st...

Dimensionless coefficient () in convergence confinement method shows the relaxation of stress in the wall of the tunnel at different excavation movements. This factor is considered a constant number in previous studies and tunnel geometric characteristics (such as depth, cross-section shape, radius, soil material, etc.) are not included in its determination; however, ignoring these effects can...

The goal of this study is investigating reduction of residual stresses from welding carbon steel plates through vibrationstress reliefmethod vs. thermal method. In order to carry out the required experimental tests, carbon steel plates were welded together under specific conditions as samples. Some of the samples were vibration stress relieved, some were thermal stress relieved while the rest r...

heat stress is one of the main obstacles for crop production in many areas of the world including southwest of iran. in order to evaluation the effect of heat stress on yield, yield component, and mopho-phenological traits of wheat, an experiment was conducted during 2010-2011 under normal (optimum sowing date) and heat stress (late sowing date) conditions on 11 wheat genotypes including yavaro...

drought stress is a major factor limiting crop production. investigation of physiological characteristics related to drought tolerance and crop production may be useful in selecting drought tolerant cultivars as well as in improving crop yield. two drought tolerant (azar2 & back cross roshan) and two drought susceptible (marvdast & shiraz) cultivars were investigated in both greenhouse and fiel...