نتایج جستجو برای: equivalent noise level
تعداد نتایج: 1367872 فیلتر نتایج به سال:
testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...
introduction: the improvement of technology has increased noise levels in hospital wards to higher than international standard levels (35-45 db). higher noise levels than the maximum level result in patient’s instability and dissatisfaction. moreover, it will have serious negative effects on the staff’s health and the quality of their services. the purpose of this survey is to analyze the level...
background: one of the most widely used equipments in harvesting hay and grains are four wheel mowers. the aim of the present study was to determine the levels of noise exposure in drivers and bystanders in different states, speeds and gear of four wheel mowers (bcs model 622). methods: the iso 5131 and iso 6814 standards were used to assess noise exposure in drivers and bystanders, respectiv...
Background and aims: In the steel industry, air blowers used to supply compressed air are considered as sources of annoying noise . This study aims to design an acoustic room chamber in order to control the noise level of the air blower. Methods: Measuring of the noise level along with frequency analysis was performed by using sound level meter, model ofCASELLA-Cell.450 . Dosimetery was per...
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...
conclusions atpl was higher in the post-monsoon season. w/s ratio and correlation analysis revealed interseasonal homogeneity of tmv and traffic noise levels and interseasonal heterogeneity of air pollutant concentrations and atpl in the city microenvironments. results atpl was 3.35 times higher in the post-monsoon and 1.83 times higher in the pre-monsoon season than the permissible limits pres...
Noise emitted from traffic contributes to about 55% of total noise pollution in India. This paper is an effort of a research conducted to quantify and analyze the traffic noise emissions along the Salem-Namakkal NH 7 corridor with an ultimate objective of setting up a traffic noise model based on the traffic noise conditions of Indian cities. Noise levels and other variables have been measured ...
Annoyance, recognition and detection of noise from a single wind turbine were studied by means of a two-stage listening experiment with 50 participants with normal hearing abilities. In-situ recordings made at close distance from a 1.8-MW wind turbine operating at 22 rpm were mixed with road traffic noise, and processed to simulate indoor sound pressure levels at LAeq 40 dBA. In a first part, w...
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