Original scientific paper Stress measurement by using ultrasonic waves is based on acoustoelasticity law, i. e. the relation between stress and wave velocity in engineering materials. Longitudinal critically refracted (LCR) wave is a popular ultrasonic wave in the ultrasonic stress measurement application. The LCR wave is a bulk longitudinal wave that travels within an effective depth underneat...

The amplitude of an ultrasonic signal generated by electromagnetic acoustic transducers (EMATs) is typically low when compared to those generated by contacting transducers, which restricts the application of EMATs in the fields of nondestructive testing and nondestructive evaluation. The transmission process of a surface wave EMAT is studied, based on a previously established 3-D model, with th...

Ultrasonic-standing-wave (USW) technology has potential to become a standard method for gentle and contactless cell handling in microfluidic chips. We investigate the viability of adherent cells exposed to USWs by studying the proliferation rate of recultured cells following ultrasonic trapping and aggregation of low cell numbers in a microfluidic chip. The cells form 2-D aggregates inside the ...

An ultrasonic particle concentrator based on a standing-wave hemispherical resonator is combined with confocal laser-scanning fluorescence detection. The goal is to perform ultrasensitive biomedical analysis by concentration of biologically active microspheres. The standing-wave resonator consists of a 4 MHz focusing ultrasonic transducer combined with the optically transparent plastic bottom o...

Address correspondence to [email protected] ABSTRACT The output of an ultrasonic wave-driven nanogenerator (NG) has been found to depend on the excitation conditions and geometry. Incidence angle tests indicate that the effective area of an NG determines the amount of power that can be generated. The output power of an NG is also directly related to its distance from the ultrasonic source. A si...

The ultrasonic wave is applied as an inspection method for the gas-holder and the pipeline in service. In such an inspection, the application of an automatic inspection system is desirable, because a manual inspection is difficult to accomplish perfectly and exactly due to its enormity, a so-called nondestructive inspection robot is then preferable. However, an ultrasonic nondestructive inspect...

A scanning probe microscope methodology, called resonant difference-frequency atomic force ultrasonic microscopy RDF-AFUM , has been developed. It employs an ultrasonic wave launched from the bottom of a sample while the cantilever of an atomic force microscope, driven at a frequency differing from the ultrasonic frequency by one of the contact resonance frequencies of the cantilever, engages t...

The inspection of large structures using conventional ultrasonic bulk wave techniques is slow because scanning is required if the whole structure is to be tested. Ultrasonic guided waves potentially provide an attractive solution to this problem because they can be excited at one location on the structure and will propagate many metres. However, guided wave testing is complicated by the presenc...

The propagation of broad bandwidth solitary wave impulses, generated within granular chains by narrow bandwidth ultrasonic excitation, is studied in detail. Theoretical predictions are compared to experimental results. It is demonstrated that the observed effects result from a sum of a solitary wave traveling out from the source with a wave that reflects from the far end of the chain. It is sho...

A method for ultrasonic measurement of friction material elastic constants was evaluated through a round-robin process. The purpose of the study was two-fold: 1) to formulate and evaluate a standard test method (SAE J2725) for measuring elastic constants using ultrasound and 2) to quantify the measurement variability when the testing method is applied by multiple operators and instrumentation. ...