نتایج جستجو برای: frequency noise
تعداد نتایج: 648515 فیلتر نتایج به سال:
original article introduction: a practical solution which is sometimes efficient for noise control in the receiver locations is to enclose workers in an acoustic cabin. accordingly, prediction of the noise insulation performance is regarded as an important aspect of the design a personnel cabin. this study empirically aims to design an acoustic cabin using sandwich panels in a typical metal i...
Noise is essential for the existence of a liquid market, and if noise traders are not present in the market, the trade volume will drop severely and an important aspect of the market philosophy will be lost. However, these noise traders bring noise to the market, and the existence of noise in prices indicates a temporary deviation in prices from their fundamental values. In particular, high-fre...
oroginal article tiller is a handy multi – a purpose tractor is used in agriculture. the noise emitted from tiller may be seriously affected auditory system users. the purpose of this study was to evaluate the exposure to noise in operators of this device. in this study 36cultivator tiller was examined. measurement of sound is based in iso 5131-1996 and iso 7216 standard and was conducted in in...
This study evaluates the impact of underwater ambient noise using seven real noise samples; Dolphin, Rain, Ferry, Sonar, Bubbles, Lightning, and Outboard Motor in three frequency ranges in extremely low frequency (ELF) band. The ELF band is the most significant bandwidth for underwater long-range communication. ELF band which is extended from 3 to 3000 Hz clearly, faces bandwidth limitation. Me...
Sound is an effective exogenous factors which affecting human brain processing mechanisms. This research was quasi experimental study that was carried out among 70 students to evaluate the effect of sound frequency on human noise annoyance. Noise annoyance degree was measured during exposure to sound at various frequencies of 500, 1000, 2000, 4000 and 8000 Hz. Sound.exe software was used to det...
A reliable speech enhancement method is important for speech applications as a pre-processing step to improve their overall performance. In this paper, we propose a novel frequency domain method for single channel speech enhancement. Conventional frequency domain methods usually neglect the correlation between neighboring time-frequency components of the signals. In the proposed method, we take...
introduction: hearing loss is one of the most common occupational diseases. in most workplaces, workers are exposed to noise and solvents simultaneously, so the potential risk of hearing loss due to solvents may be attributed to noise. in this study we aimed to assess the effect of exposure to mixed aromatic solvents on hearing in the absence of exposure to hazardous noise. materials and met...
Time-frequency filtering is an acceptable technique for attenuating noise in 2-D (time-space) and 3-D (time-space-space) reflection seismic data. The common approach for this purpose is transforming each seismic signal from 1-D time domain to a 2-D time-frequency domain and then denoising the signal by a designed filter and finally transforming back the filtered signal to original time domain. ...
low frequency noise (lfn) is ubiquitous in both occupational and general environments. mental performance of subjects exposed to lfn is expected to be impaired. individual characters seem to play a significant role in this process. this study aimed to evaluate the effects of moderate levels of lfn (20–200 hz) on mental performance. fifty-three subjects (in two groups) were exposed to low and fl...
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...
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