نتایج جستجو برای: sound pressure level
تعداد نتایج: 1531055 فیلتر نتایج به سال:
introduction: noise is one of the hazardous factors in work places such as textile industries. the objective of this study is to determine noise pollution in textile industries in kermanshah (2001). materials & methods: this study is an analytical-descriptive one. the study was done in 2 steps. in the first step the characteristics of the work place & buildings were completely determined; the...
this paper presents noise problems associated with the use of air-turbine drills in dental practice. two hundred and fifty dentists (male and female) were randomly selected from the faculty of dentistry as well as the dentists who worked private in tehran. the results indicated that the mean value of sound pressure level produced by the high-speed drills was 69.1 db. most of the energy from the...
Background and aims: The power plants, including important industry of the country in which a large number of noise sources which workers are exposed with harmful levels occupational noise. The aim of this study was designing enclosures to noise control in the feed water pumps in a power plant. Methods: This cross-sectional study and their Interventional plants were done on the ground floor ...
Background and Aim: Noise is the most common source of environmental stress that influences negatively the psychological and physiological aspects of human. The purpose of this study was determining the noise sources and assessing in General Intensive Care Unit. Materials and Methods: In this cross-sectional study, equivalent noise level "Leq 15 min", Maximum and Minimum sound pressure level we...
background: hospital is a place to provide medical services. it is affected by noise pollution sources that can be associated with negative impacts on health and comfort status of the staff members and patients. the aim of this study was to measure noise levels in different wards of hospitals and to determine the irritation caused by noise among the hospital staff members in hamadan, iran. meth...
Background: The sound is an environmental and occupational pollutant and can cause a number of reactions in human body, in which hearing loss is one of the most important effects. Cement industry is one of the industries with noise induced hazards. The aim of this study was to evaluate the noise level in different parts of Kerman Cement Plant. Materials and Methods: This descri...
background: in the steel industry, coke-fueled furnaces are used for smelting iron ore to produce cast iron are considered as sources of annoying noise.this study aims to evaluate the noise pollution blast furnace and sound source characteristics in order to present noise control measures in the steel industry. methods: measurement of noise level and its frequency analysis was performed using s...
conclusions use of flexible joint in the exhaust system leads to conversion of linear vibration to non-linear one, resulting in significant reduction of noise levels. results by using this new exhaust at speed levels of 1000, 2000, 3000, 4000, and 5000 rpm, we had respectively 3.9, 6.8, 7.4, 5.6, and 5 dba decreases in total sound level pressure. objectives this study aimed to reduce motorcycle...
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...
Background and Objectives: Over the last three decades environmental pollutions became a more noticeable problem in all around of the world. In many countries, noise pollution as a basic problem has a great importance.Development of the city, increasing of industrial centers, increasing vehicles, other annoying noise resources and also little information about the noise pollution of Tabriz city...
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