نتایج جستجو برای: acoustic noise measurement
تعداد نتایج: 694467 فیلتر نتایج به سال:
ارزیابی میزان کاهندگی صدای گوشی های ایرماف رایج برمبنای روش میدانی میکروفن داخل گوش در محیط های کاری
Background and aims Nominal noise reduction rating of the earmuff manufacturers can be different compared with the actual noise attenuation rating. The current study aimed to determine the actual noise reduction rate of current hearing protection devices in the real workplaces using a field microphone in real ear method (FMIRE). Methods: In this cross-sectional study, five common earmuffs we...
background: noise prediction is considered to be the best method for evaluating cost-preventative noise controls in industrial workrooms. one of the most important issues is the development of accurate models for analysis of the complex relationships among acoustic features affecting noise level in workrooms. in this study, advanced fuzzy approaches were employed to develop relatively accurate ...
Aims: Noise is considered the most harmful physical agents in the workplace which exposure to it can cause the harmful physical and psychological effects on worker. Since the best noise control measures is to reduce or limit the at the source, the purpose of this study was to assess the noise pollution and determine the dominant sound source in an Air production plant of a Petrochemical industr...
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...
It is accepted that noise pollution has a major impact on health, such as physical, physiological, psychological and performance related effects, all over the world. This study aims to evaluate noise pollution in four urban parks located in Sanandaj City, Iran and to zone it in GIS environment. Sound pressure level (SPL) and maximum sound level (Lmax) were measured at 45 points (each point was ...
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...
Acoustic source separation aims at estimating the contribution of each acoustic source from the signals measured at an array of microphones. The measurement signals are usually mixtures of acoustic sources and some noise contributions. When mixtures are assumed to be linear instantaneous mixtures, they can be separated by the method known as blind source separation or independent component anal...
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...
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