Analysis on Nonlinear Ultrasonic Images of Vertical Closed Cracks by Damped Double Node Model

Nonlinear ultrasonic imaging method for closed cracks using subtraction of responses at different external loads.

To improve the selectivity of closed cracks for objects other than cracks in ultrasonic imaging, we propose an extension of a novel imaging method, namely, subharmonic phased array for crack evaluation (SPACE) as well as another approach using the subtraction of responses at different external loads. By applying external static or dynamic loads to closed cracks, the contact state in the cracks ...

a study on insurer solvency by panel data model: the case of iranian insurance market

the aim of this thesis is an approach for assessing insurer’s solvency for iranian insurance companies. we use of economic data with both time series and cross-sectional variation, thus by using the panel data model will survey the insurer solvency.

Experimental Analysis of a Vertical, Double-Effect Diffusion Solar Still

Ultrasonic evaluation of closed cracks using subharmonic/ superharmonic phased array and a laser interferometer

A new method for detection and sizing of closed crack is described which uses transient waveform of subharmonics with half input frequency in ultrasonic nondestructive evaluation. In analogy to the resonant characteristics of vibration of bubbles in liquids, we formulate an equation for resonant excitation of subharmonics at partially closed cracks. The equation has been partially verified by c...

Nondestructive Evaluation of Closed Cracks Using an Ultrasonic Transit Timing Method

In this study, we investigated a method for the non-destructive detection of cracks based on an ultrasonic transit timing method. This method is considered to be an effective means for crack monitoring over an extensive coverage area. Aluminum specimens were prepared with a range of crack sizes and subjected to a tone burst wave to investigate the relationship between crack depth and the transi...