نتایج جستجو برای: equivalent sound pressure level
تعداد نتایج: 1647037 فیلتر نتایج به سال:
Background: The noise caused by traffic is an increasingly prominent feature of urban environments. However, limited studies have been focused on the assessment of exposure-response relationship between road traffic noise exposure and driving behaviors in Iran. The present study aimed to investigate the prevalence of the violations caused by road traffic noise exposure in Qazvin, Iran. Methods...
INTRODUCTION The use of Personal Digital Audio Players can cause hearing injuries, as the sound is generated directly in the ear canal. It is believed that different types of headphones can cause different amplifications, since they cause changes in the volume and resonance of the ear canal according to their depth. OBJECTIVE This study aimed to determine the sound pressure to which young ind...
background: noise is one of the most important harmful agents in work environment. noise pollution in oil refinery industries is related to workers' health. this study aimed to determine the overall noise pollution of an oil refinery operation and its frequency analysis to determine the control plan for a vent noise in these industries. methods: this experimental study performed in control unit...
the narrow operating window between pore pressure and fracture pressure makes drilling difficult in some operations. a feasibility study of managed pressure drilling (mpd) is carried out on iran darquain oil field. the previous wells drilled in this field showed that mud returns were lost during drilling gadvan formation. the present work addresses this problem by means of surface back pressure...
Background and Objective: Noise pollution is one of the serious environmental issue. Sound control technologies based on sound absorption and sound insulation are considered as the two widely used methods. Therefore, the aim of this study was to modify silica aerogel nanocomposites to improve its acoustic properties. Materials and Methods: This applied experimental research involved in examin...
AIM To evaluate the sound pressure level to which preschool students are exposed. METHOD This was a prospective, quantitative, nonexperimental, and descriptive study. To achieve the aim of the study we used an audio dosimeter. The sound pressure level (SPL) measurements were obtained for 2 age based classrooms. Preschool I and II. The measurements were obtained over 4 days in 8-hour session...
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...
Background and Aim: Noise pollution is recognized as a major problem in urban areas. Therefore, the current study was aimed to determine noise pollution indices in Birjand old districts. Materials and Methods: In this cross-sectional and analytical-descriptive study, noise measurement was performed by means of "CEL" sound level meter (model 450.490). Equivalent noise level "Leq 10 min" was meas...
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