نتایج جستجو برای: equivalent sound pressure level
تعداد نتایج: 1647037 فیلتر نتایج به سال:
Background and Objective: Noise pollution is an important environmental problem that may cause hazardous effects, such as hearng loss, sleep disorders, hypertension and digestive problems in communities. To prevent these effects, achieving recommended standards of noise pollution measuring in cities is mandatory. This study was aimed to evaluate noise pollution in zanjan city in 2007. Materials...
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...
Active noise control systems tend to be designed with a target on sound pressure level reduction. However, the perceived control efficiency for the occupants can be more accurately assessed if psychoacoustic metrics are taken into account. The aim of this paper is to evaluate the effect of an adaptive structural acoustic controller on the sound quality of engine noise in a vehicle mockup. The e...
The study aims to diagnose the sound pressure levels inside incubators in a controlled environment under free-field conditions. tests were carried out semi-anechoic room standard UNE-EN ISO 3745:2012/A1:2018 three different operating states: off, on, and on with temperature alarm triggered. Sound analyzed models of incubators, both outside. main noise indices corrected equivalent continuous lev...
Background : Cement industry has many process units. Basically all of these units can be considered as a source of noise. Since noise pollution is defined based on its offensive hearing effects, the importance of the noise sources depends directly on the number of workers in the unit. Materials and Methods : An experimental study has been done at Tehran cement factory to recogn...
Noise pollution is one of the common physical harmful factors in many work environments. The current study aimed to assess personal and environmental sound pressure level project sound-Isosonic map Razavi Khorasan Paste manufacture using Surfer V.14 at V.5.0. This cross-sectional, descriptive analytical that was conducted 2018 factory contains Canister, production Brewing unit. Following ISO 96...
Introduction & Objective: Noise is one of the most important harmful agents in work environment. In spit of industrial improvements, exposure with over permissible limit of noise is counted as one of the health complication of workers. In Iran, do not exact information of the absorption coefficient of acoustic materials. Iranian manufacturer have not laboratory for measured of sound absorbanc...
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