نتایج جستجو برای: vibration stress
تعداد نتایج: 487237 فیلتر نتایج به سال:
Whole-body vibration training using single-frequency methods has been reported to improve bone mineral density. However, the intensities can exceed safe levels and have drawn unfavorable comments from subjects. In a previous article, whole-body vibration training using multiple vibration displacements at multiple vibration frequencies (MVDMVF) was reported. This article presents the computation...
Heat shock protein levels are increased in cells as a result of exposure to stress. To determine whether heat shock protein regulation could be used to evaluate stress in cells during spaceflight, the response of Jurkat cells to spaceflight and simulated space shuttle launch vibration was investigated by evaluating hsp70 and hsp27 gene expression. Gene expression was assessed by reverse transcr...
Simultaneous vibration welding of 304 stainless steel was carried out with an eccentric circulating vibrator and a magnetic telescopic vibrator at subresonant (362 Hz and 59.3 Hz) and resonant (376 Hz and 60.9 Hz) frequencies. The experimental results indicate that the temperature gradient can be increased, accelerating nucleation and causing grain refinement during this process. During simulta...
O'BRIANT, C. R., and M. K. OHLBAUM. Visual acuity decrements associated with whole body ±Oz vibration stress. Aerospace Med. 41(1): 79-82. 1970. The fact that vibration has an adverse effect on visual acuity is well established but inadequately quantified. The operational acceleration environments of lo*v altitude terrain avoidance flight, the increasing use of helicopters, and the potential vi...
The Japan Society for Occupational Health (JSOH) recommends the Occupational Exposure Limits (OELs) as reference values for preventing adverse health effects on workers caused by occupational exposure to chemical substances, continuous or intermittent noise, impulsive or impact noise, heat stress, cold stress, whole-body vibration, hand-arm vibration and time-varying electric, magnetic and elec...
The Japan Society for Occupational Health (JSOH) recommends the Occupational Exposure Limits (OELs) as reference values for preventing adverse health effects on workers caused by occupational exposure to chemical substances, continuous or intermittent noise, impulsive or impact noise, heat stress, cold stress, whole-body vibration, hand-arm vibration and time-varying electric, magnetic and elec...
a considerable amount of energy is released in the form of shock wave from explosive charge detonation. shock wave energy is responsible for the creation of crushing and fracture zone around the blast hole. the rest of the shock wave energy is transferred to rock mass as ground vibration. ground vibration is conveyed to the adjacent structures by body and surface waves. geological structures li...
Background and Objectives: Bus drivers are exposed to harmful agents such as noise and vibration which may led to increasing the level of job stress among them. The aim of this study was to evaluation of job stress among urban bus drivers with respect to daily noise and vibration exposures. Methods: This cross-sectional study carried out with participation of 103 urban bus drivers in Hamadan, ...
in this research, the surface stress effect on the nonlocal vibration of piezoelectric square plate reinforced by single walled carbon nanotubes (swcnts) based on classical plate theory (cpt) and first order shear deformation theory (fsdt) is presented. the elastic properties of piezoelectric nanocomposite plate are estimated by eshelby-mori-tanaka and the extended mixture rule approaches. the ...
OBJECTIVES A three-dimensional finite element (FE) model of the lumbar spine L3-L5 segment, the ligaments of which were assumed to be nonlinear materials, was established based on the actual vertebra geometry to investigate the influence of the injury lumbar spine on its adjacent components on the condition of whole-body vibration. Several injury conditions of the spine components were assumed,...
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