نتایج جستجو برای: vibration acceleration

تعداد نتایج: 95291  

Journal: :international journal of occupational hygiene 0
parvin nassiri department of occupational health engineering, tehran university of medical sciences, tehran, iran. irajali mohammadi department of occupational health engineering, occupational health research center, iran university of medical sciences, tehran, iran. mohammadhosein beheshti department of occupational health engineering , faculty of health, gonabad university of medical sciences, gonabad , iran. kamal a azam department of biostatistics, school of public health, tehran university of medical sciences, tehran, iran.

the purpose of this study was to assess exposure to hand-arm vibration in tiller users, forty users of tiller in northeastern provinces of iran were examined to measure hand-arm vibration parameters such as root mean square acceleration (rms), total equivalent acceleration, vibration dose value (vdv) and crest factor in three directions (x, y, and z) and various operating modes for comparing th...

ژورنال: مهندسی دریا 2006
بهزاد, مهدی, سلماسی, حمید, سیف, محمدسعید, کاظم زاده حنانی, سیامک,

In this paper, several models of structure-fluid coupling are employed to investigate on the vibration behavior of the structure. Using basic equations of vibration and employing a mathematical model, a single degree of freedom system is analyzed. Some parameters of the mathematical model are obtained from test. To examine structure-flow interaction, coupled system of nonlinear second-order dif...

2001
Shiyu Zhou Jianjun Shi

Since many rotor systems normally operate above their critical speeds, the problem of accelerating the machine through its critical speeds without excessive vibration draws increasing attention. This paper provides an analytical imbalance response of the Jeffcott rotor under constant acceleration. The response consists of three parts: transient vibration due to the initial condition of the roto...

2016
Johnny Padulo Riccardo Di Giminiani Antonio Dello Iacono Alessandro M. Zagatto Gian M. Migliaccio Zoran Grgantov Luca P. Ardigò

We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration...

Journal: :Annals of agricultural and environmental medicine : AAEM 2012
Leszek Solecki

The objective of the study was to recognize and evaluate the annual exposure of private farmers to whole body mechanical vibration on selected family farms of mixed production profile (plant-animal). The scope of study covered the carrying out of time schedules of agricultural activities, and measurements of the frequency weighted vibration acceleration (m/s(2)), expressed as effective values (...

Journal: :The Annals of occupational hygiene 2009
Lage Burström Ronnie Lundström Mats Hagberg Tohr Nilsson

This study clarifies whether the established frequency weighting procedure for evaluating exposure to hand-transmitted vibration can effectively evaluate the temporary changes in vibrotactile perception thresholds due to pre-exposure to vibration. In addition, this study investigates the relationship between changes of the vibrotactile perception thresholds and the normalized energy-equivalent ...

ژورنال: طب کار 2014
جلیل پور, یاسر, رجبی, حسن, رجبی, عباسعلی, زیندینی, محمد, فروهر مجد, فرهاد,

Background: Vibration of body especially that of hand-arm is a key factor in developing inconvenience in drivers, which decreases efficiency, triggers fatigue and disturbance in physiological activities, and finally predisposes drivers to occupational diseases and traffic accidents. This study examines the effect of hydraulic steering wheel system on controlling and attenuation of the vibration...

ژورنال: طب کار 2018

Introduction: Fork-lifts are considered as one of the main sources of vibration at workplaces. Due to importance of the risks from exposure to vibration, the present study was aimed to investigate health risk due to exposure of fork-lift drivers to whole body vibration at two position with load and without load in an Automobile industry. Method: In this cross sectional study, the evaluation of...

ژورنال: طلوع بهداشت یزد 2015
امکانی, مجتبی , برخورداری, ابوالفضل, ذوالعلی, فرزانه, هاشمی نژاد, ناصر,

Introduction: Cars can cause whole body vibration with different intensities which result in discomfort and musculoskeletal disorders in the exposed persons. Heavy mine vehicles based on the working environment, capacity, and power can produce considerable vibration to be transferred to the operator. The purpose of this study was to assess whole body vibration in the drivers of heavy mine vehic...

Ali Jafari, Hojat Ahmadi, Masoud Feyzi,

Introduction: Due to the non-developed mechanization situation, chainsaw is a widely used tool in Iranian forests. This tool can trigger unwelcome disorders (e.g., white finger syndrome) due to the transmitted vibrations from its handle to the body members. Characterizing these vibrations can result in minimizing the intensity of these disorders. This study aims to investigate the effect of dif...

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