نتایج جستجو برای: sound

تعداد نتایج: 104142  

Journal: :journal of biotechnology and health sciences 0
karim jabbari occupational health department, tehran university of medical sciences, tehran, ir iran; occupational health department, tehran university of medical sciences, tehran, ir iran parvin nassiri occupational health department, tehran university of medical sciences, tehran, ir iran mohammad reza monazzam esmaeelpour occupational health department, tehran university of medical sciences, tehran, ir iran kamal azam department of epidemiology and biostatistics, tehran university of medical sciences, tehran, ir iran mohammad faridan department of occupational health, tarbiat modares university, tehran, ir iran leila heidari tehran east health center, tehran, ir iran

background exposure to the excessive levels of occupational noise is one of the principal harmful agents affecting the workers’ health. this study aimed to investigate the relationship between the occupational noise exposure and the hearing loss caused by working in small-scale service industries in the city of damavand, close to the metropolitan capital city of tehran, iran. methods this descr...

We investigated the issue of noise pollution in the Bidboland gas refineryby noise measurement and surveys. The Bidboland gas refinery has several process units.The sound pressure levels were measured at several places, such as units of 200, 300,400, 500, boiler, powerhouse area, cooling towers pumps, and maintenance area, and thecorresponding noise maps were produced by using sound plan softwa...

Background: Today, the effects of environmental pollution on human life and human needs, which reduces the level of community health caused by traffic noise in large cities, are clearly visible by creating irritation and pathogenic conditions. The aim of this study was to assess the risk of noise pollution resulted from central traffic in Shiraz by analyzing its indicators and related componen...

Aerospace engines testing is a source of noise pollution and determining the low frequency acoustic characteristics of the test cell, plays an important role in optimally control of the sound field and reducing the level of sound pressure and pollution. In this study, the drop in average sound pressure level is numerically predicted by constructing a test cell according to ISO 140 standard. To ...

Barmar, Mohammad , Farhang Dehghan, Somayeh , Hajizadeh, Roohalah , Jonidi Jafari, Ahmad , Khavanin, Ali ,

Introduction: Nowadays multiple techniques have been developed to noise control. One the most important way is the control based on sound absorption and insulation. The purpose of current study was to improve the acoustic properties of soft polyurethane foam regarding combined sound absorption and insulation characteristics. Materials and Methods: Polyacrylonitrile and polyvinylidine fluoride ...

Journal: :مهندسی بیوسیستم ایران 0
عیسی زارع قلعه عبدشاهی کارشناس مرکز تحقیقات رضا یگانه معاون آموزشی دانشکده کشاورزی/ دانشگاه ایلام

birds, sometimes numbering in millions, can cause serious damage to grain fields. in order to find a method to accordance with environmental issues and effective in controlling these birds, in this research, the effect of sound was studied for keep birds away. the broadcast unit was developed with the following design criteria: 1) three sound levels of hawk, gas gun and sparrow distress, with f...

A Najlerahim B No’doust G Tarighat Saber R Nilipour S Clarke

The human auditory cortex is the gateway to the most powerful and complex communication systems and yet relatively little is known about its functional organization as compared to the visual system. Several lines of evidence, predominantly from recent studies, indicate that sound recognition and sound localization are processed in two at least partially independent networks. Evidence from human...

The widespread use of squirrel cage fans, especially in ventilation and home and industrial environments, has led to the formation of many research efforts to improve performance and reduce the sound produced by this type of fan. In the literature, the most important factor in generating sound in this category of fans is the confrontation between the rotor exit flow and the volute of the fan. I...

Journal: :Journal of Environmental Conservation Engineering 1996

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