in this paper we are going to show the importance of mode identification in microtremor array analysis. the idea come from four concentric ambient noise array recordings with aperture 100 to 1000 meters, performed in southern urban area of tehran near the shrine of imam khomeini. these measurements were part of a comprehensive research project with the aim of determination of deep shear wave ve...

Previous discussions of Alfvdn wave propagation across an inhomogeneous plasma predicted that shear Alfvin waves become singular (resonant) at the w = kzuA layer and that there is a strong wave absorption at this layer giving localized ion heating. In this paper the three standard derivations of the Alfvdn ‘resonance’ (incompressible magnetohydrodynamics, compressible magnetohydrodynamics, and ...

doppler ultrasound can provide important information about vascular problems through the analysis of blood flow wave-form. the purpose of this study was obtaining the normal images of color doppler and estimation of blood flow velocity parameters of femoral artery in rabbits. left and right femoral arteries of 8 healthy adult new zealand rabbits were evaluated. color and spectral doppler images...

uniaxial compressive strength (ucs) and internal friction coefficient (µ) are the most important strength parameters of rock. they could be determined either by laboratory tests or from empirical correlations. the laboratory analysis sometimes is not possible for many reasons. on the other hand, due to changes in rock compositions and properties, none of the correlations could be applied as an ...

A theory of compressional and shear wave propagation in consolidated porous media ~rocks! is developed by extending ideas already introduced in connection with unconsolidated marine sediments. The consolidated material is treated as an elastic medium which exhibits a specific form of stress relaxation associated with grain boundaries and microcracks. The stress relaxation, which is linear in th...

Otoacoustic emissions provide unambiguous evidence that the cochlea supports energy propagation both towards, and away from, the stapes. The standard wave model for energy transport and cochlear mechanical amplification provides for compressional and inertial waves to transport this energy, the compressional wave through the fluids and the inertial wave along the basilar membrane via fluid coup...

Acoustic emission testing (AET) often utilises waveguides to separate delicate sensors from hot surfaces or to facilitate access to otherwise obstructed materials such as lagged vessels. In the authors’ work, restricted access to mechanical seals on a hot water pump necessitated the use of a short rod to transmit acoustic emission (AE) information from the ceramic seal face. Consequently, an ap...

Uniaxial compressive strength (UCS) and internal friction coefficient (µ) are the most important strength parameters of rock. They could be determined either by laboratory tests or from empirical correlations. The laboratory analysis sometimes is not possible for many reasons. On the other hand, Due to changes in rock compositions and properties, none of the correlations could be applied as an ...

Introduction: Large scale reductions in compressional velocity caused by impact-induced damage is an important but largely unstudied feature of impact craters [1]. Damage depth beneath impact craters can be used to extract information about the impact cratering process. A new non-destructive method is developed to study the damage structure beneath impact craters in the laboratory. Experimental...