نتایج جستجو برای: noise sources
تعداد نتایج: 473529 فیلتر نتایج به سال:
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...
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...
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...
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...
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 ...
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...
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...
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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