نتایج جستجو برای: noise

تعداد نتایج: 194715  

Around the word, traffic growth is causing growing air and noise pollution. Noise levels in a given area are affected by traffic on the streets as well as effective factors, including existing infrastructure and industrial centers, and so on. The purpose of this research is to model and estimate the amount of acoustic emission in the streets of Tehran's third district, using the 3D spatial info...

دهقان, حبیب اله, غریب, سیف اله,

Introduction: In some jobs, physical activity can be done in high noise pollution that can affect the heart rate. The aim of this study was to investigate the effects of noise exposure and physical activity on heart rate in the hot and humid conditions. Materials and Methods:  This experimental study was performed on 14 healthy men in hot and humid climatic chamber (35 °C, 75% RH). ...

Journal: :international journal of automotive engineering 0
younesian hamzavi rostam

in recent years, need to increase the convenience of trips in railway vehicles causes that train operators and manufacturers focus on reducing the noise level which is sensed by passengers. in this paper, first the state of modeling acoustic noise in cab train is discussed and natural frequencies and acoustic mode shapes are derived and then formulation of acoustic pressure in the cab will be o...

آزادی, نمامعلی , ساقی, محمد حسین , صادقی, شهرام ,

Background: One of the critical unit in each hospital is intensive care unit (ICU). The United States’ Environmental Protection Agency (EPA) recommends to control the noise level of this unit in order to not exceed 45 decibels (dBA) during the day and 35 dBA at night. In this study, our goal was to evaluate the noise level at adult and neonatal ICUs at some Sanandaj’s hospitals, Iran. Methods:...

Background: Ototoxic chemicals can impair the sense of hearing and balance. In the past decades, the ototoxicity of solvents and their interaction with noise have become evident. This study has been carried out in the shoe manufacturing factory in Tehran (Iran) with the aim of evaluating the combined effects of noise and toluene on the workers' hearing. Materials and Methods: This cross-sect...

Journal: :journal of rehabilitation sciences and research 0
yones lotfi university of social welfare and rehabilitation sciences saiede kargar mohanna javanbakht akbar biglarian

background: one of the most common complaints expressed by individuals with hearing-impairment is the difficulty in speech perception in background noise. different tests have been developed for the evaluation of reduced ability of speech perception in noise, and the consonant-vowel in noise test is one of the simplest one regard to speech materials. the goal of the present study was developmen...

بهزادی, محمد حسن , مصطفایی , مریم , نصیری, پروین ,

Introduction: According to previous researches, working at the airport is one of the most vociferous jobs in the world. Airport workers are at risk of noise induced hearing loss. The present study was done to evaluate the Sound Pressure Level (SPL) in the closest aprons to Ground Safety department at Mehrabad airport and to investigate the effect of airport noise on the employees of this depart...

Quality of speech signal significantly reduces in the presence of environmental noise signals and leads to the imperfect performance of hearing aid devices, automatic speech recognition systems, and mobile phones. In this paper, the single channel speech enhancement of the corrupted signals by the additive noise signals is considered. A dictionary-based algorithm is proposed to train the speech...

Journal: :international journal of environmental research 0

noise pollution can be considered as the most important problem of urban environmental management in mega metropolises and urban transportation is the main source of the mentioned problem. this study aims to investigate the amount of traffic noise dose received by traffic policemen in tehran; district 1 municipality. the investigation was conducted during three consecutive months in 2007 in 282...

Journal: :فیزیک زمین و فضا 0
رامین موقری ژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران غلام جوان دولوئی پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران مژگان نوروزی پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران احمد سدیدخوی گروه فیزیک زمین، موسسه ژئوفیزیک دانشگاه تهران

the mixture of natural and artificial seismic sources with random distributions cause diffuse wave field with random amplitudes and phases called noise. when noise is analyzed in a long-term process, it contains surface waves which are spread in all directions. thus, ambient noise contains data relevant to the surface waves. in recent years, as broadband seismic networks have been distributed v...

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