نتایج جستجو برای: equivalent sound pressure level
تعداد نتایج: 1647037 فیلتر نتایج به سال:
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...
This paper describes a method for determining a semi-empirical, equivalent simple-source model that accounts for the sound radiation in the vicinity of a high-performance military aircraft. The characteristics of the equivalent source are guided by previously reported observations of jet noise, namely that the strengths of the partially correlated sources are distributed asymmetrically. The par...
OBJECTIVES Spatial assessment of traffic noise pollution intensity will provide urban planners with approximate estimation of citizens exposure to impermissible sound levels. They could identify critical noise pollution areas wherein noise barriers should be embedded. The present study aims at using the Geographic Information System (GIS) to assess spatial changes in traffic noise pollution in ...
The fluidization behavior of silica gel was tested in a fluidized bed under different sound pressure levels and sound frequencies. It has been found that the particle mixtures can be fluidized smoothly with sound assistance at low sound frequency owing to the sound energy disrupting large size of agglomerates. The minimum fluidization velocity was found to decrease with increasing sound frequen...
Frequency resolution is a fundamental capacity of the auditory system that underlies the perception of all complex sounds. The development of this capacity has not been well characterized in humans. This investigation used a nonsimultaneous pulsation threshold technique to examine the development of infant frequency resolution. Psychophysical tuning curves were obtained for 3- and 6-month-olds ...
results according to the study results, noise levels in a co2 plant’s house and control room ranged from 88 to 102 db and 79 to 82 db (a), respectively. in order to reduce the amount of emitted noise in the co2 plant house and control room, a noise control plan was implemented in each part of the facility; it was met with effective results. conclusions the findings of this investigation have cl...
In this paper, we design, simulate, and build an ultrasonic heat generator. In thermoacoustics, heat generated by the passage of alternating current through a thin conductor produces a sound wave. In this method, unlike other methods of sound production, moving parts are not used to vibrate air molecules, and as a result, the frequency response of these generators is flatter than other sound ge...
Introduction & Objective: Noise exposure, risk exposure in a wide range of work station, especially oil and gas industry and related companies is considered. This study was carried out to evaluate the noise before and after corrective action in 11 operational units of tanks and transportation in Abadan oil refining company. Methods: First, the basic information including the location of noise ...
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