refractor ambiguities are big problem in seismic refraction method especially in seismic engineering. there can be hidden subsurface geological phenomena such as hidden faults and shear zones which are not simply predicted by the travel-time graph or some geophysical methods. head wave amplitudes are used to show the resolution of refractor ambiguities and the existence of anisotropy in complex...

â â â  avicenna and the arabic phonetics â â â â â  * mahmood shakib ansari â  * * alireza yusofi â â â  abstract â  avicenna, the iranian philosopher and sage, mostly famous for his scientific works such as law and the shifa has done some studies in arabic phonetics as well. besides pointing to some physical aspects of sounds in the above mentioned books, he has also written a monograph in ara...

in the current paper, we have studied the effect of dark energy on for-mation where dark energy exists in the background. for this purpose, we used both wmap9 and planck data to study how the radius changes with redshift in these mod-els. we used different data sets to fix the cosmological parameters to obtain a solution for a spherical region under collapse. the mechanism of structure formation f...

introduction: to report our experience with a large series of surgical procedures for removal of cerebellopontine angle (cpa) tumors using different approaches.   materials and methods: this was a retrospective analysis of 50 patients (mean age, 49 years) with cpa tumors (predominantly acoustic neuroma) who underwent surgical removal using appropriate techniques (principally a translabyrinthine...

Non-Riemannian geometry of acoustic non-relativistic turbulent flows is irrotationally perturbed generating a acoustic geometry model with acoustic metric and acoustic Cartan contortion. The contortion term is due to nonlinearities in the turbulent fluid. The acoustic curvature and acoustic contortion are given by Dirac delta distributions. Violation of Lorentz invariance due to turbulence is c...

Hybrid CAA-approaches are commonly used for aeroacoustic engineering applications. In this kind of computational techniques, the numerical domain is split into a noise generating region, where an aerodynamic field generates the acoustic sources, and an acoustic propagation region. Nowadays a large variety of hybrid approaches exist differing from each other in the way the source region is model...