نتایج جستجو برای: acoustic wave

تعداد نتایج: 289789  

The acoustic wave velocity depends on elasticity and density at most materials, but because of anisotropy and especially piezoelectric coupling effect, the acoustic wave propagation at piezoelectric based crystalloacoustic materials, is an applied and challenging problem. In this paper, using modified Christoffel's equation based on group velocity concept, the effect of anisotropy and piezoelec...

Massah, H.R., Momeni-Masuleh, S.H., Setvati-Zirak, A.,

Investigating waves propagation’s equation in the atmosphere is one of the important and widely used issues in various sciences, which has attracted many researchers. A type of propagating waves is an acoustic-gravity wave. These type of waves have a lot of stationarity properties and can be propagate to a high altitude in the atmosphere. The equation of acoustic-gravity wave propagation is a h...

Journal: :iranian journal of public health 0
m shayeghi dept. of medical entomology and vector control, school of public health, tehran mh dehghani dept. of environmental health engineering, school of public health, tehran university of medical sci am fadaei dept. of environmental health engineering, school of public health, tehran university of medical sci

background: organophosphorus pesticides are one of the most prevalent usages for pest control in the country. such pesti­cides enter into water sources by different routes. since drinking of contaminated water at the higher doses than the standard level, may causes undesirable effects to human health and ecosystem. the object of this research was to investigate the ef­fect of various parameters...

Journal: :international journal of environmental research 2012
a.r. noorpoor a. sadighzadeh h. habibnejad

the removal of fine particles less than 2.5 μm in diameter generated from industrial plantsrepresents a serious challenge in air pollution abatement. these particles can penetrate deeply into the lungs and are difficult to remove by cyclones, electrostatic precipitators, and other conventional separation devices. in this paper, the influence of acoustic waves on removing aerosol particles from ...

The mathematical modeling of the acoustic wave propagation in seawater is the basis for realizing goals such as, underwater communication, seabed mapping, advanced fishing, oil and gas exploration, marine meteorology, positioning and explore the unknown targets within the water. However, due to the existence of various physical phenomena in the water environment and the various conditions gover...

Ultrasonic horn with transfer of acoustic wave into an aqueous solution results in unique properties. When, transfer of sound wave into a liquid results in liquid movement in the direction of wave propagation which gradually loses its energy due to the viscous friction. This wave motion induces a flow which is known as acoustic streaming or micro-streaming. In this article, a simple innovative ...

Javad Farzi

This paper concerns with the modeling and construction of a fifth order method for two dimensional acoustic wave equation in heterogenous media. The method is based on a standard discretization of the problem on smooth regions and a nonstandard method for nonsmooth regions. The construction of the nonstandard method is based on the special treatment of the interface using suitable jump conditio...

عبداله, امیر, ملکی, مسعود,

Propagation and dispersion of acoustic waves is one of the important phenomena in physics. Acoustic-waves are nowadays widely used in a variety of applications ranging from underwater communications, identification and specification of the internal defects of materials to extracorporeal shock wave lithotripsy. Apart from application and utilization of such phenomena, study on production and pro...

In this paper, the acoustic wave propagation in multilayer Thue-Morse structures has theoretically been studied. The composing layers were assumed do be Cu, Al, Mgo and Pb materials. Two, three or four different materials have been used in a typical structure. By using a perpendicular incident acoustic wave, the transmission coefficient was calculated and then by its old, the frequency gaps was...

Journal: :iranian journal of science and technology (sciences) 2013
m. shahmansouri

dust acoustic (da) solitary waves are investigated in an unmagnetized dusty plasma comprising of fluid warm dust particles and kappa distributed ions. we assume the electron number density to be sufficiently depleted in this fluid model, i.e., ne  nd . we consider the usual ad hoc damping term, involving the damping rate  due to the dust–neutral collisions; and derived the modified dis...

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