This study proposes a portable long distance laser ultrasonic propagation imaging (LUPI) system with associated damage visualization algorithms based on anomalous wave propagation imaging (AWPI) methods with adjacent wave subtraction, reference wave subtraction, reference image subtraction, and the variable time window amplitude mapping (VTWAM) for a robust SHM solution.

The influence of ultrasonic pretreatment prior to vacuum drying of Chinese fir specimens was examined in this work. In the pretreatments, wood samples were immerged in a distilled water bath and were treated using two wave frequencies for four different elapsed times to investigate effects of ultrasonic frequency and treatment duration. Then the wood samples were vacuum-dried at 80°C and absolu...

Several different strategies are being considered for ultrasonic structural health monitoring systems using a variety of approaches. Guided wave techniques for interrogating large plate-like structures have probably generated the most interest; these methods have the potential of monitoring large areas with a low sensor density while remaining sensitive to defects. The acousto-ultrasonic nondes...

Abstract The ultrasonic (longitudinal and transverse) velocities and the transport and magnetic properties of polycrystalline La0.25Ca0.75Mn1−xCrxO3 (x = 0, 0.03, 0.05, and 0.07) have been studied systematically. It was found that with increasing Cr content, the resistivity increases, the charge-ordering transition temperature TCO shifts to low temperature, and the magnetic moment of the system...

Continuous-wave ultrasonic modulation of scattered laser light has been used to image objects in tissue-simulating turbid media for what is to our knowledge the first time. The ultrasound wave focused into the turbid media modulates the laser light passing through the ultrasonic focal zone. The modulated laser light collected by a photomultiplier tube reflects the local mechanical and optical p...

In a low-frequency ultrasonic guided wave dual-probe flaw inspection of a square steel bar with a finite length boundary, the flaw reflected pulse wave cannot be identified using conventional time monitoring when the flaw is located near the reflection terminal; therefore, the conventional ultrasonic echo method is not applicable and results in a non-detection zone. Using analysis and simulatio...

The aim of this study was to evaluate ultrasonic P-wave velocity as a feature for predicting some physical and mechanical properties that describe the behavior of local building limestone. To this end, both ultrasonic testing and compressive tests were carried out on several limestone specimens and statistical correlation between ultrasonic velocity and density, compressive strength, and modulu...

An electric field built inside a crystal was proposed to enhance photoinduced carrier separation for improving photocatalytic property of semiconductor photocatalysts. However, a static built-in electric field can easily be saturated by the free carriers due to electrostatic screening, and the enhancement of photocatalysis, thus, is halted. To overcome this problem, here, we propose sonophotoca...

Nonlinear properties of lead zirconate-titanate ~PZT! piezoceramics are investigated using ultrasonic second harmonic generation technique. When a sinusoidal ultrasonic wave of frequency v0 is sent into a nonlinear material, the second harmonic wave with frequency 2v0 is generated. Through measuring the absolute amplitude of the fundamental (v0) and of the second harmonic (2v0) waves, the ultra...