نتایج جستجو برای: acoustic noise measurement

تعداد نتایج: 694467  

1997
Christophe Couvreur

Introduction Noise pollution has become an important problem in our society. Noise assessment regulations require the measurement and evaluation of noise. The basic equipment for this measurement is the noise monitoring systems (or NMS). The current generation of NMS consists of "dumb" systems that record noise level and, possibly, noise spectra, over programmed periods of time. The interpretat...

Journal: :The Journal of the Acoustical Society of America 2009

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی امیرکبیر(پلی تکنیک تهران) - دانشکده مهندسی 1385

با توجه به اینکه زبان فارسی زبانی نسبتا هجامحور است در این پروژه تقطیع سیگنال گفتار فارسی به واحدهای هجایی مورد توجه قرار گرفته است. هدف از این پروژه آن است که تنها با استفاده از سیگنال گفتار و کمیت های پروزودیک آن، تقطیع به واحدهای هجایی در محیط تمیز و آلوده به نویز با صحت قابل قبولی انجام شود. در این کار ابتدا انرژی زمان کوتاه سیگنال گفتار مورد پردازش قرار گرفته است. روش های مورد استفاده در ...

1999
Marianne Mosher Michael E. Watts Jorge Bardina

A processing system has been developed to meet increasing demands for detailed noise measurement of aircraft in wind tunnels. Phased arrays enable spatial and amplitude measurements of acoustic sources, including low signal-to-noise sources not measurable by conventional measurement techniques. The Microphone Array Phased Processing System (MAPPS) provides processing and visualization of acoust...

ژورنال: سلامت کار ایران 2014

  Abstract   Background and aims: Occupational noise is a major cause of hearing loss and tinnitus. In the present study, acoustic characteristics of tinnitus were evaluated and their relation with hearing loss and nervousness was studied.   Methods: Our study was performed on 56 male workers aged between 40 to 56 years including 28 workers with accompanied hearing loss and tinnitus and a long ...

2000
Qamar A. Shams Kenneth D. Wright Charles B. Lunsford Charlie D. Smith

Langley Research Center (LaRC) has for years been a leader in field acoustic array measurement technique. Two field-deployable digital measurement systems have been developed to support acoustic research programs at LaRC. For several years, LaRC has used the Digital Acoustic Measurement System(DAMS) for measuring the acoustic noise levels from rotorcraft and tiltrotor aircraft. Recently, a seco...

Journal: :journal of computational applied mechanics 0
masoud ghasemian department of mechanical engineering, university of tehran, tehran, iran amir nejat department of mechanical engineering, university of tehran, tehran, iran

the current study presents the results of the aerodynamic noise prediction of the flow field around a naca 0012 airfoil at a chord-based reynolds number of 100,000 and at 8.4 degree angle of attack. an incompressible large eddy simulation (les) turbulence model is applied to obtain the instantaneous turbulent flow field. the noise prediction is performed by the ffowcs williams and hawkings (fw-...

Journal: :international journal of occupational and environment medicine 0
m amirabadi division of surgery, nioc health organization, shiraz

[no abstract available]

درویشی, ابراهیم , علی آبادی, محسن , گلمحمدی, رستم ,

Introduction: In the steel industry,air blowers used to supply compressed air are considered as sources of annoying noise. This study aims to acoustics analysis of theairblower workroomand sound source characteristics in order to present noise controlmeasuresinthe steel industry. .Material and Method: Measurement of noiselevel and its frequency analysis was performed usingsound levelmetermod...

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