نتایج جستجو برای: noise levels

تعداد نتایج: 1099855  

Journal: :journal of biotechnology and health sciences 0
ahmad nikpey department of occupational health, qazvin university of medical sciences, qazvin, ir iran mehran ghalenoei department of occupational health, qazvin university of medical sciences, qazvin, ir iran; department of occupational health, qazvin university of medical sciences, qazvin, ir iran. tel: +98-2833328212, fax: +98-2833345862 ali safary variani department of occupational health, qazvin university of medical sciences, qazvin, ir iran hamed nadri department of occupational health, shahid beheshti university of medical sciences, tehran, ir iran

background noise at intensive care units (icu) has an adverse effect on patients and icu staff. there are some evidences that sleep, recovery from critical illness and average background noise in hospitals as recommended by the us environmental protection agency (epa) and world health organization (who) should not exceed 30 a-weighted decibel (dba) and peaks during night time should be less tha...

حاج علی زاده, حسین, علی آبادی, محسن, چاوشی, ابراهیم,

Introduction: Application of agricultural machineries such as tractor has been yielded a considerable development in different agricultural activities and productions. However, noticeable health problems such as noise pollution impact the users of these off-road vehicles. The purpose of this study was to determine the noise level induced by agricultural tractors and to evaluate the driver’s noi...

Removing salt and pepper noise is an active research area in image processing. In this paper, a two-phase method is proposed for removing salt and pepper noise while preserving edges and fine details. In the first phase, noise candidate pixels are detected which are likely to be contaminated by noise. In the second phase, only noise candidate pixels are restored using adaptive median filter. In...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1389

growing demands and requires of high data rate systems cause significant increase of high frequency systems for wideband communication applications. as mixers are one of the main blocks of each receivers and its performance has great impact on receiver’s performance; in this thesis, a new solution for ku-band (12-18 ghz) mixer design in tsmc 0.18 µm is presented. this mixer has high linearity a...

Farnaz Khadivi Fatemeh Masjedi Mohammad Hossein Mohammadi Mahdiabadi Hasani shima mohammadi,

Background: The recruitment of medicinal herbs for the treatment of psychological disorders such as anxiety and stress has a long history. The purpose of the present study was to investigate the compensatory effects of hydroalcoholic extract of green tea on anxiety behaviors that are induced by noise stress in male Wistar rats. Methods: In this study, male Wis...

Journal: :European journal of dental education : official journal of the Association for Dental Education in Europe 2006
J C Sampaio Fernandes A P O Carvalho M Gallas P Vaz P A Matos

OBJECTIVE To measure and analyse noise levels in the learning-teaching activities at the Dental School of the University of Porto (Portugal). MATERIALS AND METHODS Sound levels were measured in five different practice areas and laboratories, selected as representative of a variety of learning-teaching activities. The noise levels were determined using a precision sound level meter that was po...

Journal: :محیط شناسی 0
محمد حسین صیادی اناری استادیار گروه محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه بیرجند افسانه موفق دانشجوی دکتری دانشکدۀ محیط زیست و انرژی دانشگاه آزاد واحد علوم و تحقیقات تهران

introduction noise pollution is one of the environmental pollution that threats public health to the survival of organisms. urban traffic causes noise pollution as a major factor of air pollution. this is one of the problems of urban citizens. this is also a growing problem that has a potential impact on public health, which is mainly resulted from transport vehicles in the cities and the resid...

2013
Justin L. Rogers JUSTIN L. ROGERS

Journal: :iranian journal of electrical and electronic engineering 0
شایق shayegh محمدی mohammadi عبدی پور abdipour صدقی sedghi میرزاوند mirzavand

a direct conversion modulator-demodulator with even harmonic mixers with emphasis on noise analysis is presented. the circuits consist of even harmonic mixers (ehms) realized with antiparallel diode pairs (apdps). we evaluate the different levels of i/q imbalances and dc offsets and use signal space concepts to analyze the bit error rate (ber) of the proposed transceiver using m-ary qam schemes...

Journal: :international journal of occupational hygiene 0
rostam golmohammadi department of occupational hygiene, faculty of public health and research center for health sciences, hamadan university of medical sciences, hamadan, iran. mohsen aliabadi department of occupational hygiene, faculty of public health and research center for health sciences, hamadan university of medical sciences, hamadan, iran.

original article   introduction: a practical solution which is sometimes efficient for noise control in the receiver locations is to enclose workers in an acoustic cabin. accordingly, prediction of the noise insulation performance is regarded as an important aspect of the design a personnel cabin. this study empirically aims to design an acoustic cabin using sandwich panels in a typical metal i...

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