نتایج جستجو برای: acoustic noise
تعداد نتایج: 271819 فیلتر نتایج به سال:
background : cement industry has many process units. basically all of these units can be considered as a source of noise. since noise pollution is defined based on its offensive hearing effects, the importance of the noise sources depends directly on the number of workers in the unit. materials and methods : an experimental study has been done at tehran cement factory to recognize and analyze...
Background : Cement industry has many process units. Basically all of these units can be considered as a source of noise. Since noise pollution is defined based on its offensive hearing effects, the importance of the noise sources depends directly on the number of workers in the unit. Materials and Methods : An experimental study has been done at Tehran cement factory to recogn...
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...
Transmission loss and noise reduction of reactive mufflers are determined by linear acoustic theory and unsteady flow field study, respectively. The effects of extending the inlet tube of the muffler, adding holes to the extension, and the number of holes on both transmission loss and noise reduction are investigated. In noise reduction analysis, the Navier-Stokes equations and k-ε model are us...
Objectives: Voice is influenced by personality. However, it is still questionable which acoustic features are influenced by personality traits. This study aimed to investigate the relationship between acoustic characteristics and personality dimensions. Methods: Thirty-three participants with dysphonia and 33 participants without dysphonia were recruited to take part in this cross-sectional st...
Introduction: This study was conducted to assess noise pollution in one of thepetrochemical complex andtakepractical measures to reduce it. Thecompanyis located in site 4 of Mahshahr Special Economic Zone. . Method and Materials: In the first phase of the research, environmental noise was measured to determine the noise levelsin the different sections of the plant and also identify the main s...
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 ...
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 ...
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-...
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