A frequency domain tomographic inversion was developed to estimate frequency dependent energy attenuation by using prestack depth migration common image gathers (CIGs). The frequency dependent attenuation is estimated from the centroid frequency difference for reflections in CIGs. Migration stretch and ghost effects are taken into account to get correct measurements of frequency. This method ma...

In this research work cobalt-ferrite (CoFe2O4) nanoparticles were synthesized by a simple, general sol-gel auto-combustion method. For this study, electromagnetic (EM) wave absorbing coatings with different weight fractions of nano-carbon and CoFe2O4 (which, arises from both dielectric and magnetic contributions) and polymeric epoxy resin were prepared and their characteristics were fully inves...

To prevent serious electromagnetic interference, a single-layer and double layer wave-absorbing coating employing complex absorbents composed of carbon black with epoxy resin as matrix was prepared. The morphologies of carbon black /epoxy composites were characterized by scanning electron microscope  and atomic force microscope, respectively. The carbon black  particles exhibit obvious polyarom...

In this paper, the turbulent air droplet flow inside a single passage of a curved type vane separator has been studied numerically. The simulation is based on the Eulerian - Lagrangian method. For turbulent air flow calculations, a computer code was developed to solve the Reynolds Averaged Navier Stokes (RANS) equations together with the equations of Reynolds Stress Transport Model (RSTM) o...

In this research, at first, Ce-substituted barium ferrite, BaCe0.2Fe11.8O19 was prepared via the sol-gel method as a substrate and then Carbon NanoTubes (CNTs) was synthesized on the surface of the substrate by Chemical Vapor Deposition (CVD) technique. The structure, morphology, and electromagnetic performance of the synthesized nanocompos...

In this research work, airplane grade aluminum alloy substrate was coated by Al2O3/ TiO2 ceramic coatings in two different compositions as 50:50 and 87:13 using Flame spraying technique. The surface & cross-sectional morphological characterizations of the Al2O3/ TiO2 powders and coatings were performed by scanning electron microscopy (SEM). The microwave absorbing properties of coatings were ex...

Ocean bottom reflectivity has been studied for a simple layered sedimentary model at shallow depth. Reflections from the bottom were determined from standard geophysical reflection data. The plane wave reflections have been obtained as bottom loss (-20log|R|) from the available reflection seismic data. Bottom loss estimated in the 10-250 Hz band are presented as functions of frequency and of an...

A general review and comparison on two types widely adopted measurement techniques of dielectric constant and dielectric loss at microwave frequencies has been undertaken. Characteristics of various transmission/reflection techniques and resonance techniques are compared with each other. Suggestions on how to select adequate measurement techniques of microwave dielectric properties are given. T...