نتایج جستجو برای: noise sources

تعداد نتایج: 473529  

2008
Dimitri Papamoschou

This study relates to the imaging of noise sources that are distributed and strongly directional, such as in turbulent jets. The goal is to generate noise source maps that are self-consistent, i.e., their integration over the extent of the noise source region gives the far-field pressure autospectrum for a particular emission direction. This is possible by including a directivity factor in the ...

2012
Ph. Lerch P. Dumas T. Schilcher A. Nadji A. Luedeke N. Hubert L. Cassinari M. Boege J.-C. Denard L. Stingelin L. Nadolski T. Garvey S. Albert Ch. Gough M. Quack J. Wambach M. Dehler J.-M. Filhol

Today, the vast majority of electron storage rings delivering synchrotron radiation for general user operation offer a dedicated infrared port. There is growing interest expressed by various scientific communities to exploit the mid-IR emission in microspectroscopy, as well as the far infrared (also called THz) range for spectroscopy. Compared with a thermal (laboratory-based source), IR synchr...

2001
Peter D. Burns Don R. Williams

A procedure that enables the evaluation and further distillation of fixed pattern noise for digital capture devices is proposed. This method also allows for the direct calculation of the random, or temporal, noise contribution, devoid of fixed pattern components. Our method is consistent with a draft digital camera noise measurement standard under consideration through ISO 15739, but is intende...

2007
Shaohua Yang Aleksandar Kavcic

We consider a linear Gaussian noise channel used with delayed feedback. The channel noise is assumed to be an ARMA (autoregressive and/or moving average) process. We reformulate the Gaussian noise channel into an intersymbol interference channel with white noise, and show that the delayed-feedback of the original channel is equivalent to the instantaneous-feedback of the derived channel. By gen...

2016
L. Bjørnø

An overview over the most important results obtained over the past of noise produced in water by impacts of single droplets, artificial rain and real rain is presented. Two distinct sources form the major contributors to rainfall produced noise in the sea. The raindrop impact and the pulsations of entrained air bubbles. The impact sound is produced by raindrops of all sizes, while the bubble pu...

2011
Fabrice Ardhuin Eleonore Stutzmann Martin Schimmel Anne Mangeney

[1] Noise with periods 3 to 10 s, ubiquitous in seismic records, is expected to be mostly generated by pairs of ocean wave trains of opposing propagation directions with half the seismic frequency. Here we present the first comprehensive numerical model of microseismic generation by random ocean waves, including ocean wave reflections. Synthetic and observed seismic spectra are well correlated ...

2015
Laura Ermert Antonio Villaseñor Andreas Fichtner

S U M M A R Y We develop and apply a novel technique to image ambient seismic noise sources. It is based on measurements of cross-correlation asymmetry defined as the logarithmic energy ratio of the causal and anticausal branches of the cross-correlation function. A possible application of this technique is to account for the distribution of noise sources, a problem which currently poses obstac...

2004
Narendra Singh

The study examines the problem of noise pollution in the wake of its ill effect on the life of the people. A crosssection survey of the population in Delhi State points out that main sources of noise pollution are loudspeakers and automobiles. However, female population is affected by religious noise a little more than male population. Major effects of noise pollution include interference with ...

Journal: :The Journal of the Acoustical Society of America 2011
J Kennedy O Adetifa M Carley N Holt I Walker

The prevalence of noise in the riding of motorcycles has been a source of concern to both riders and researchers in recent times. Detailed flow field information will allow insight into the flow mechanisms responsible for the production of sound within motorcycle helmets. Flow field surveys of this nature are not found in the available literature which has tended to focus on sound pressure leve...

ژورنال: سلامت کار ایران 2012
نصیری, پروین , کاوسی, امیر , حمیدی, منصوره, دهقان, حمیدرضا , همدانی, ابوالفضل, کیانی, سجاد ,

  Background and aims: Noise pollution is one of the risk factors of the human environment that may seriously threat physical and mental health of human beings. One of the main sources of this type of pollution is the noise produced by urban transportation and traffic, particularly subway in the environment. This article aims at study and evaluation of the noise condition in drivers’ cabin and ...

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