نتایج جستجو برای: noise control methods

تعداد نتایج: 3072762  

Journal: :Mechanical Systems and Signal Processing 2021

This paper investigates the effect of changes in environment on performance two widely-used virtual sensing methods for active noise control (ANC): remote-microphone method and additional-filter method. Robust adaptive feedforward algorithms incorporating such techniques is essential to achieving attenuation at designated locations practice, when subject uncertainties environment. Off-line simu...

Journal: :jundishapur journal of health sciences 0
behzad fouladi dehaghi department of occupational health, school of public health, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of occupational health, school of public health, ahvaz university of medical sciences, ahvaz, ir iran. tel: +98-6113738282, fax: +98-6113367543 parvin nassiri department of occupational health, school of public health, tehran university of medical sciences, tehran, ir iran mohammad reza monazam department of occupational health, school of public health, tehran university of medical sciences, tehran, ir iran leila ebrahimi ghavam abadi department of environmental management, islamic azad university, science and research branch, ahvaz, ir iran e saeed farahani department of audiology, school of rehabilitation, tehran university of medical sciences, tehran, ir iran gholamreza hassanzadeh department of anatomy, school of medicine, tehran university of medical sciences, tehran, ir iran

background noise exposure is known as a risk factor for hearing loss and one of its effects is noise-induced stress. cortisol as a stress hormone is used in noise-induced stress assessments. objectives the aim of this study was to measure and compare saliva cortisol concentrations in the morning and evening in normal work day and rest day in both case and control groups and to assess the associ...

ژورنال: طب کار 2015

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...

پایان نامه :موسسه آموزش عالی غیردولتی رودکی تنکابن - دانشکده ادبیات و زبانهای خارجی 1383

abstract this study examined the relationship between noticing pronunciation and the improvement pronunciation by administering a 50 item story, as proficiency- test in order to investigate the effectiveness of noticing pronunciation on the improvement of pronunciation. accordingly 60 qualified students were selected and assigned to the two groups of experimental and control randomly, each gr...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1393

this thesis attempts to measure learning styles, self efficacy and intrinsic motivation as predictors of iranian ielts reading comprehension. in order to address this issue, a quantitative study was conducted on some randomly selected intact students at ferdowsi university. these two groups were assigned as they were undergraduate (ba=91) and graduate (ma =74) students; they were all aged betwe...

Journal: :journal of research in health sciences 0
rostam golmohammadi mohammad reza monazzam maryam nourollahi ali nezafat samaneh momen bellah fard

background: the adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. the objective of this study was to evaluate the noise characteristics of compressors ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی صنعتی کرمان - پژوهشکده برق و کامپیوتر 1390

a phase-locked loop (pll) based frequency synthesizer is an important circuit that is used in many applications, especially in communication systems such as ethernet receivers, disk drive read/write channels, digital mobile receivers, high-speed memory interfaces, system clock recovery and wireless communication system. other than requiring good signal purity such as low phase noise and low spu...

ناظم, فرزاد, پیری, خسرو, کریمی, امیرحسین,

Background: There is a long history of using physical activities and herbal medications to cure psychological diseases such as stress and anxiety. The aim of this study was to assess the effect of training, extract of Althaea kurdica flower and noise stress on the anxiety of Wistar male rats. Methods: Thirty-five male rats were randomly divided into five groups: the noise group (n=7), traini...

Journal: :jundishapur journal of health sciences 0
farhad forouharmajd department of occupational health engineering, school of public health, isfahan university of medical sciences, isfahan, ir iran mitra shabab department of occupational health engineering, school of public health, isfahan university of medical sciences, isfahan, ir iran; department of occupational health engineering, school of health, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; occupational health engineering department, school of health, ahvaz jundishapur university of medical sciences, ahvaz, ir iran. tel: +98-6133738269, fax: +98-33738282

conclusions according to the factory noise map, except for the control rooms with 81 dba noise, other cases of measuring stations were higher than the standard exposure of 85 dba noise. as a result, the implementation of control strategies, such as inspection and performance of control systems and insulation of the control room to prevent unnecessary exposure noise, are necessary. background st...

ژورنال: سلامت کار ایران 2015
احمدی, عمران, عطرکار روشن, صدیقه,

Background and aims: Based on various studies, the noise can have a significant effect on human health. Annoyance is the most common bad effect that may be caused by the noise and traffic. Awareness of costs of traffic noise has various advantages in decision making and on control measures to reduce the traffic noise. Therefore, the purpose of this study is to analyze the costs of traffic noi...

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