This study reports different properties of ionospheric perturbations detected to the west and south Korean Peninsula after Hunga-Tonga volcanic eruption on 15 January 2022. Transient wave-like total electron content (TEC) modulations intense irregular TEC are in Peninsula, respectively, about 8 hr eruption. The propagate away from epicenter with a speed 302 m/s. Their occurrence time, propagati...

Shear wave velocity (Vs) data are key information for petrophysical, geophysical and geomechanical studies. Although compressional wave velocity (Vp) measurements exist in almost all wells, shear wave velocity is not recorded for most of elderly wells due to lack of technologic tools. Furthermore, measurement of shear wave velocity is to some extent costly. This study proposes a novel methodolo...

The propagation of the fundamental symmetric Lamb mode S0 along wz-BN/AlN thin composite plates suitable for telecommunication and sensing applications is studied. The investigation of the acoustic field profile across the plate thickness revealed the presence of modes having longitudinal polarization, the Anisimkin Jr. plate modes (AMs), travelling at a phase velocity close to that of the wz-B...

Piezoelectric transducers have been widely used for the generation and detection of ultrasonic waves for structural health monitoring. Recently, we proposed the use of inductive coupling in order to implement wireless coupling to a Lamb wave transducer. In that transducer the ultrasonic waves were generated by a piezoelectric wafer attached to the surface of a plate. These transducers are effec...

Structural health monitoring (SHM) is an emerging technology with great potential in structural diagnosis and prognosis. SHM systems can be passive or active. Active SHM systems rely on structural interrogation using active sensors (transducers) that can transmit and receive ultrasonic Lamb waves traveling at large distances in the structural material. Piezoelectric-wafer active sensors (PWAS) ...

Theory of Lamb Wave propagation in plate-like structures have found many practical applications in Structural Health Monitoring. However for better understanding of complex physical phenomena associated with wave propagation and wave interaction with damage numerical simulations are as important as laboratory experiments. The paper shows the application of Cellular Automata technique for modeli...

background: we sought to assess right ventricular (rv) systolic and diastolic functions via tissue doppler imaging (tdi) in order to discriminate right-to-left (bidirectional) from left-to-right intracardiac shunts. methods: a tissue doppler velocity study via doppler echocardiography was performed in 20 patients with left-to-right shunt (without evidence of significant pulmonary hypertension) ...

Ultrasonic guided waves inspection using Lamb waves is suitable for damage detection in metallic structures. This paper will present experimental results obtained using guided Lamb waves to detect flaws in aluminum specimens with design features applicable to space applications. Two aluminum panels were fabricated from a variable-thickness aluminum top plate, with two bolted I-beams edge stiffe...