To improve the defect detectability of Lamb wave inspection systems, the application of nonlinear signal processing was investigated. The approach is based on a Warped Frequency Transform WFT to compensate the dispersive behavior of ultrasonic guided waves, followed by a Wigner-Ville time-frequency analysis and the Hough Transform to further improve localization accuracy. As a result, an automa...

The rouge waves in an optically injected semiconductor lasers are receiving a lot of interest. In this work, the generating and controlling of the rogue waves in semiconductor lasers have been investigated. For this purpose, the laser’s rate equations are solved numerically in a specified time interval, then the field amplitude and the intensity versus time are calculated and analyzed. To solve...

A mathematical model is considered to investigate the behavior of horizontally polarized shear waves (SH-waves) in fluid saturated porous medium sandwiched between heterogeneous half-spaces. Heterogeneity in the upper half-space is due to linear variation of elastic parameters, whereas quadratic variation has been considered for lower half-space. The method of separation of variables and Whitta...

We investigate the generation of acoustic phonons from electrostriction of optical waves in small core waveguides. We specifically consider simple step-index strip waveguides composed of silica or silicon in air, with sub-micron lateral dimensions. Such waveguides support one or a few optical modes, but a rich spectrum of acoustic phonons that becomes densely populated as the phonon frequency i...

Guided waves have been the attractive ways for the nondestructive inspection of the large structure because of their many advantages. The characteristics of guided waves are presented; some consideration of guided waves in the large structure inspection is stated; excitation methods and their merits and shortcomings are introduced. Several typical applications of guided waves in the large struc...

Guided Waves Testing is a new technology of ultrasonic testing of NDT bloomed in recent years especially for pipes and boards inspection in industry. Different methods used in guided waves signal processing are analyzed. The contrast between Fourier and Wavelet analysis is presented to support the outstanding features of wavelet in the processing of signals with sudden changes, such as guided w...