seismic waves when crossing the earth in heterogeneous and anisotropic environments, having interaction. recognizing the impact of these factors on the seismograms help us to find out more information about interior of the earth. coda waves are the main reason for the random heterogeneities in earth. local earthquakes in the northeast region of iran with epicentral distance less than 200 km is ...

Ultrasonic wedges which can propagate one longitudinal L and two orthogonally polarized shear S waves are presented. In order to use this wedge to generate and received guided plate acoustic waves along a metal plate at high temperatures brass which has a slow L and S wave velocities was chosen. Mode conversion method was used to convert L to S waves in the wedge. The mode conversion efficiency...

Background: An electroencephalogram (EEG) is an accepted method in neurophysiology with a wide application. Different types of brain rhythms indicate that simultaneous activity of the brain cortex neurons depend on the person’s mental state. Method: we have focus on reviewing the existing literature pertaining to changes of the brain’s bioelectrical activity that recorded from the ...

[1] We report properties of substorm-related, globally excited Alfvén waves on a temporal scale of 6 to 300 s (3.3 to 167 mHz) at geocentric distances between 5 and 6 RE. The waves were observed in the tail lobes and the plasma sheet boundary layer (PSBL) by the Polar satellite. In each region we made the following observations: (1) The tail lobe Alfvén waves started at substorm onset as determ...

electrocardiographic (ecg) parameters and cardiac rhythms have been evaluated and published in different breeds of beef and dairy cattle but there is limited information regarding these parameters in healthy sheep. this study is aimed to investigate the ecg parameters in balouchi sheep. the ecg parameters including the amplitudes of p, q, r, s and t waves, duration of p, qrs and t waves and p-r...

The Fourier spectrum of waves in the Pacific Ocean is analysed. The power in 4 s waves is more regular than the power in 10 s waves and larger than expected.

alfvén waves dissipation is an extensively studied mechanism for the coronal heating problem. these waves can be generated by magnetic reconnection and propagated along the reconnected field lines. here, we study the generation of alfvén waves at the presence of both steady flow and sheared magnetic field in the longitudinally density stratified of solar spicules. the initial flow is assumed to...

In this paper, we are concerned with the detection of point-like obstacles using elastic waves. We show that one type of waves, either the P or the S scattered waves, is enough for localizing the points. We also show how the use of S incident waves gives better resolution than the P waves. These affirmations are demonstrated by several numerical examples using a MUSIC type algorithm.

Earth’s rotation causes splitting of normal modes. Wave fronts and rays are, however, not affected by Earth’s rotation, as we show theoretically and with observations made with USArray. We derive that the Coriolis force causes a small transverse component for P waves and a small longitudinal component for S waves. More importantly, Earth’s rotation leads to a slow rotation of the transverse pol...