نتایج جستجو برای: noise sources

تعداد نتایج: 473529  

Journal: :acta medica iranica 0
azam moslehi department of physiology & pharmacology, school of medicine, qom university of medical sciences, qom, iran. fatemeh nabavizadeh department of physiology, school of medicine, tehran university of medical sciences, tehran, iran. mansoor keshavarz department of physiology, school of medicine, tehran university of medical sciences, tehran, iran. nematollah rouhbakhsh department of audiology, tehran university of medical sciences, tehran, iran. masoud sotudeh department of pathology, shariati hospital, tehran university of medical sciences, tehran, iran. ehsan salimi department of pharmacy, tehran university of medical sciences, tehran, iran.

noise is considered as one of the most severe sources of environmental and workplace constraints. many noise effects are well known on immune function, hormonal levels, cardiovascular and respiratory systems. in this study, our aim is to evaluate the effects of traffic noise exposure on basal and stimulated gastric pepsin secretion. 48 male rats were exposed to traffic noise (86 db) for a short...

ژورنال: مهندسی دریا 2013

The noise and hydrodynamics of two propeller models were investigated. First, the non-cavitating and cavitating flow was analyzed in different operating conditions around the marine propellers using the finite volume method (FVM). The hydrodynamic tests of the propeller were performed in the cavitation tunnel and similar results were observed between the numerical and experimental results. Sec...

Journal: :international journal of occupational hygiene 0
seyedehzahra jalilzadeh islamic republic of iran broadcasting university, tehran, iran. mohammad asgari islamic republic of iran broadcasting university, tehran, iran. mohammadebrahim sadeghi islamic republic of iran broadcasting university, tehran, iran.

acoustic experimental data of irib (islamic republic of iran broadcasting) server room was taken to measure the acoustic noise characteristics of frequency and sound pressure level (spl). the purposes of this paper are measuring the noise pollution and its evaluation through the regulations. the measurements were taken in two stages. the first one was taken at 10 points by sound investigator 22...

اسدی, هادی , ذوالقدر, زهرا , ظریف یگانه, مروارید , عارفیان, ایمان , منظم اسماعیل پور, محمدرضا ,

Introduction: Vehicle engine id one of the main sources of noise which its level is influenced by various parameters. The aim of this study was to investigate the impact of motor oils quality before and after oil change on the variability of vehicle engine induced noise level. In this study it is tried to follow-up the efficacy of motor oil quality on engines sound level. .Material and Method...

Journal: :The Journal of the Acoustical Society of America 1996
B Berglund P Hassmén R F Job

The sources of human exposure to low-frequency noise and its effects are reviewed. Low-frequency noise is common as background noise in urban environments, and as an emission from many artificial sources: road vehicles, aircraft, industrial machinery, artillery and mining explosions, and air movement machinery including wind turbines, compressors, and ventilation or air-conditioning units. The ...

2010
Cedric Roberts

Low frequency noise (LFN) is common as background noise in urban environments and as an emission from many artificial sources: road vehicles, aircraft, industrial machinery, artillery and mining explosions, and air movement machinery including wind turbines, compressors, and indoor ventilation and air conditioning units (Tempest, 1976; Leventhall, 1988 from St Pierre and Maguire [1]). LFN may a...

2005
David Robertson Christian Killow Harry Ward Jim Hough Gerhard Heinzel Antonio Garcia Vinzenz Wand Ulrich Johann Claus Braxmaier

The LISA Technology Package (LTP) uses laser interferometry to measure the changes in relative displacement between two inertial test masses. The goals of the mission require a displacement measuring precision of 10 pm Hz−1/2 at frequencies in the 3–30 mHz band. We report on progress with a prototype LTP interferometer optical bench in which fused silica mirrors and beamsplitters are fixed to a...

2010
Nicholas Harmon Catherine Rychert Peter Gerstoft

S U M M A R Y We demonstrate that the distribution of seismic noise sources affects the accuracy of Green’s function estimates and therefore isotropic and anisotropic tomographic inversions for both velocity and attenuation. We compare three methods for estimating seismic noise source distributions and quantify the potential error in phase velocity, azimuthal anisotropy and attenuation estimate...

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