نتایج جستجو برای: statics and vibration

تعداد نتایج: 16842813  

Journal: :iranian red crescent medical journal 0
seyyed ali moussavi najarkola department of occupational hygiene, collage of health, shahid beheshti university of medical sciences, tehran, ir iran ali khavanin department of occupational health, school of medical sciences, tarbiat modares university, tehran, ir iran; department of occupational health, school of medical sciences, tarbiat modares university, tehran, ir iran, tel: +98-2182883849, fax: +98-2182883825 ramazan mirzaei department of occupational health, health promotion research center, zahedan university of medical sciences,zahedan, ir iran mojdeh salehnia department of anatomical sciences, school of medical sciences, tarbiat modares university, tehran, ir iran ahad muhammadnejad cancer research center, iran cancer institute, tehran university of medical sciences, tehran, ir iran

background many industrial devices have an excessive vibration which can affect human body systems. the effect of vibration on cochlear histology has been as a debatable problem in occupational health and medicine. objectives due to limitation present in human studies, the research was conducted to survey the influence of vibration on cochlear histology in an animal model. materials and methods...

Journal: :علوم کاربردی و محاسباتی در مکانیک 0
سعید امینی محمدرضا خسروجردی مهدی محمدی مهر

this research is carried out to design and manufacturing of lathe vibration tool and their tests. firstly, one-dimensional vibration tool is designed and made of the bending vibration mode. one-dimensional vibration tool with half piezoelectric rings is considered to excite the bending mode of tool. structure of vibration tool is designed in abaqus software about 20 khz and then is made with re...

Journal: :Journal of Applied Mechanics 1966

Journal: :مهندسی بیوسیستم ایران 0
حسین جوادی کیا دانشگاه رازی کرمانشاه لیلا ندرلو دانشگاه رازی کرمانشاه علی سفرنگیان دانشگاه رازی مصطفی مصطفایی دانشگاه رازی سید سعید محتسبی دانشگاه تهران

in this study, the mf285 tractor engine vibrations resulting from the use of different combinations of biodiesel, bioethanol and diesel as fuel were studied. engine vibrations in three directions and three engine speeds: 1000, 1600 rpm 2000 and ten fuel level was measured. to investigate the influence of measured parameters on engine vibration of factorial design in a randomized complete block ...

Journal: :international journal of occupational hygiene 0
farough mohammadian parvin nasiri omid giahi zahra rezvani mehdi kangavari athena rafieepour

original article   noise and vibration are the common problems in industrialized countries which can affect individual's job performance. the present study aimed to investigate the combination of the whole body vibration and the noise and their effects on the students' mental performance in the laboratory setting. twenty male students of tehran university of medical sciences, tehran, iran were ...

Journal: :مهندسی بیوسیستم ایران 0
فیض اله شهبازی استادیار، دانشکدۀ کشاورزی، دانشگاه لرستان سعید محمدزاده استادیار، دانشکده کشاورزی دانشگاه لرستان

improper transportation of agricultural materials causes mechanical damage to them. the damage isdepended to the physical and mechanical properties of the product and properties of the appliedforce. vibration generated by vehicles during road transportation causes shake the product, contactit with carrier bin and other components, tissues deformation and damage to product. this researchwas cond...

Journal: :تحقیقات نظام سلامت 0
اصغر نیک روش استادیار، گروه مهندسی بهداشت حرفه ای، دانشگاه علوم پزشکی شیراز، شیراز، ایران زهرا زمانیان دانشجوی کارشناسی ارشد ارگونومی، گروه ارگونومی، دانشگاه علوم پزشکی شیراز، شیراز، ایران مجتبی خدادادی مربی، گروه روانشناسی، دانشگاه امام حسین(ع)، تهران، ایران محمدرضا منظم دانشیار، گروه مهندسی بهداشت حرفه ای، دانشگاه علوم پزشکی تهران، تهران، ایران جعفر حسن زاده دانشیار، گروه اپیدمیولوژی، دانشگاه علوم پزشکی شیراز، شیراز، ایران

background: deficiency of attention and concentration is one of great reasons of traffic incidents and it covers between 20 to 50 percent of events due to careless and mindedness. studies show that attention and concentration are considered as one of important cognitive components in safe driving. vibration is an important physical effect in all vehicles. till now has not been any organized stu...

Journal: :journal of agricultural science and technology 2012
m. sadeghi m. h. khoshtaghaza

black tea sample was dried by a vibro-fluidized bed dryer to find its aerodynamic behavior and thermal performance during drying. the drying experiments were conducted at three different inlet air temperatures of 100, 115 and 130°c and fluidization condition at five vibration intensity levels of 0 (no vibration), 0.063, 0.189, 0.395 and 1.184. the results showed that bed channeling and defluidi...

Journal: :ماشین های کشاورزی 0
حمید قربانپور محمد هادی خوش تقاضا محمدرضا مستوفی سرکاری

manual citrus harvesting is commonly performing hard, expensive and time consuming. in this study, a factorial experiment with a completely randomized design in three replications was performed to find out the effect of frequency (three levels of 5, 7.5 and 10 hz), vibration time (three levels of 10, 15 and 20 seconds) on harvesting capacity and losses of thomson cultivar of orange. the results...

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