نتایج جستجو برای: equivalent sound pressure level
تعداد نتایج: 1647037 فیلتر نتایج به سال:
Introduction: Low frequency sound is one of the most important sources of sound in the environment. Some individual differences such as extraversion, neuroticism, and sound sensitivity are factors that influence the effect of sound on cognitive functions. The purpose of this study was to investigate the effect of personality type (introversion/extraversion) on cognitive Performances in the pres...
The advantage of using the normal component of the particle velocity rather than the sound pressure in the hologram plane as the input of conventional spatial Fourier transform based near field acoustic holography (NAH) and also as the input of the statistically optimized variant of NAH has recently been demonstrated. This paper examines whether there might be a similar advantage in using the p...
A-weighted equivalent continuous noise levels of nine companies/industries in Jos-Bukuru metropolis were determined by using Impulse Precision Sound Level Meter Type 2209 in conjunction with -Octave Filter set Type 1616 and an audiometric test of five hundred and twenty four workers out of a total of seven hundred and ninety one volunteers interviewed were carried out. The physical measurements...
Simultaneous audio and video were recorded of a silver perch Bairdiella chrysoura producing its characteristic drumming sound in the field. The background noise contribution to the total sound pressure level is estimated using sounds that occurred between the pulses of the silver perch sound. This background contribution is subtracted from the total sound to give an estimate of the sound pressu...
Introduction: noise pollution has a negative effect on physiological parameters, efficiency and auditory system. The aim of this study was to evaluate the performance of a sound screening method for estimating sound risk in small workshops of Hamadan city. Methods: This cross-sectional study was conducted in 22 plants with more than 20 workers. Noise screening was done using a screen...
With the increase of English teaching courses, specific vocal characteristics teachers in are studied and used as basic data for design teachers’ spatial acoustics. In order to study this problem, three different voice materials were read a anechoic room under sound intensity levels: large, medium small, respectively, so analyse equivalent continuous pressure level (SPL) frequency characteristi...
Background and aims The influences of Low Frequency Noise (LFN) on mental performance have been the objectives of many papers in recent years. Many researchers believe that the LFN even at low pressure levels has impacts on mental performance. In the present work the influences of LFN and Reference Noise (RN) at two different sound pressure levels (45 & 65 dBA) on mental performances of co...
The Research has shown that the primary sound source in centrifugal turbomachines is the blade passing frequency noise, which is caused by due to impac rotor exit flow with the volute and the wild pressure fluctuations. In this paper, a centrifugal blower with forward facing blades has been selected and the sound created by it in the output channel has been investigated in different operating c...
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