نتایج جستجو برای: noise
تعداد نتایج: 194715 فیلتر نتایج به سال:
Background and aims Noise induced hearing loss is a permanent,usually, bilateral hearing impairment due to long term exposure to high levels of noise and exposure of workers to noise represents one of the most common occupational hazards. Although noise has also been suggested to increase the prevalence of hypertension, evidence for this association is not conclusive. This historical coh...
background : noise pollution and workers' noise exposure are common in industrial factories in iran. in order to reduce this noise pollution, evaluation and investigation of noise emission are both necessary. in this study, different noise mapping methodsare used for determining the distribution of noise. materials and methods : in the present study, for preparing a noise map in a hall o...
background: sound produced by the passing traffic contributes to noise pollution. noise pollution affects the residents of both city and suburban areas. the noise produced does not only disturb the community living nearby the main road during the day but becomes worse during the night. the purpose of the study is to perform noise level measurement and subjective evaluation on the noise produced...
Introduction: One of the possible effects of occupational exposure to high noise is high blood pressure and cardiovascular disease. Aim of this study was to investigate the association between noise with blood pressure and heart rate in an automotive industry. Methods: 78 male workers who worked in an automobile factory, were participated. Blood pressure and heart rate were measured in the m...
Background & Objectives: Noise is one of the most detrimental factors in working environments that alongside other physical problems have adverse effects on the mental health of employees. Open plan offices such as banks are under the influence of noise pollution sources, which can have a negative impact on health and comfort of employees. This study aimed to identify the sources of noise...
Background and Aims: Traffic noise is one of the most important urban noise pollution, which causes various physical and mental effects, impairment in daily activities, sleep disturbances, hearing loss and the impact on job performance. Thus it can reduce concentration significantly and increase the rate of traffic accidents. Some individual differences such as personality types in noise effe...
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...
In this paper, an intuitive analysis of a phase noise reduction technique is done, and then a modified structure is proposed to achieve higher phase noise reduction than the original one. This method reduces the impact of noise sources on the phase noise by decreasing closed-loop gain in zero-crossings points and moving this high closed-loop gain to the non-zero-crossings points. This reduction...
sar (synthetic aperture radar) image enhancement and segmentation is purpose of this thesis. sar image segmentation is a primary step before steps such as classification and target recognition. the main obstacle in sar image segmentation is inherent speckle noise. speckle noise is a multiplicative and highly destructive noise which results to intensity inhomogeneity. hence common segmentation m...
we compared the extent of temporary threshold shift (tts) and hair cell loss following high level 4 khz noise exposure with those preconditioned with moderate level 1 and 4 khz octave band noise. fifteen male albino guinea pigs (300- 350 g in weight) were randomly allocated into three groups: those exposed to 4 khz octave band noise at 102 db spl (group 1, n=5); those conditioned with 1 khz oct...
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