In coda wave interferometry, one records multiply scattered waves at a limited number of receivers to infer changes in the medium over time. With this technique, we have determined the nonlinear dependence of the seismic velocity in granite on temperature and the associated acoustic emissions. This technique can be used in warning mode, to detect the presence of temporal changes in the medium, ...

In part II of this two-part tutorial we review the underlying theory of seismic interferometry and discuss various new advances. In the 1990’s the method of time-reversed acoustics was developed. This method employs the fact that the acoustic wave equation for a lossless medium is invariant for time-reversal. When ultrasonic responses recorded by piezoelectric transducers are reversed in time a...

Optical fiber based Extrinsic Fabry-Perot Interferometric (EFPI) sensor significantly emerged as an advanced optical sensor for the health monitoring of civil, mechanical and aeronautical structures. This sensor responds its well capability also towards the measurement of acoustic/shock wave pressure. This paper presents an approach for high blast (acoustic/shock wave) pressure measurement usin...

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...

optical interferometry is being used as an efficient tool to analyse smooth surfaces for more than a century. although, due to introduction of novel computer assisted analyzing techniques and array detectors, like ccd, the speed and the precision of processing have been increased tremendously, but the main equation involved is not changed. the main equation is the intensity distribution in the ...

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 ...