Finite element (FE) modelling of ultrasonic propagation using Comsol Multiphysics, or indeed any other FE software, inevitably involves large computations because two or three dimensional time-stepping models are needed to predict the behaviour of these kinds of travelling mechanical waves. Comsol can be used to create video of waves in these models, which is both attractive and informative. Un...

The lethal effects of high-intensity airborne sonic (9.9 kc/sec) and ultrasonic waves (30.4 kc/sec) on spores of Bacillus subtilis var. niger ATCC 9372 were determined. The spores, which were deposited on filter-paper strips, were exposed to sound waves for periods varying from 1 to 8 hr, at a temperature of 40 C and a relative humidity of 40%. Significant reductions in the viable counts of spo...

Recent years have seen a growing interest in underwater communication and some progress has been made in this area. However, underwater communication is still immature compared with terrestrial communication. A prime reason for this is that the underwater environment is intrinsically not suitable for propagation of electric waves. Instead, ultrasonic waves are mainly used for underwater communi...

The modeling of the interaction between piezoelectric wafer active sensors (PWAS) and structural waves and vibration is addressed. Three main issues are discussed: (a) modeling of pitch-catch ultrasonic waves between a PWAS transmitter and a PWAS receiver by comparison between exact Lamb wave solutions and various finite element method (FEM) results; (b) analytical modeling of the power and ene...

Probing material degradation and properties change to anticipate stages of damage can be achieved using advanced in-situ and hybrid non-contact remote ultrasonic sensing including laser generation and air-coupled detection arrangements. The sensing technology is based on application of guided waves such as plate (Lamb waves) or surface waves (Rayleigh waves) for direct material interrogation th...

People have difficulty understanding ultrasonic sensing because they cannot see sound. The purpose of simulation is to overcome this problem by visualizing the scattering of ultrasonic waves off objects. The lattice gas model calculates wave behavior with finite difference equations to produce data suitable for grayscale visualization. This visualization is useful when designing ultrasonic sens...

The embedded ultrasonic structural radar (EUSR) was developed based on phased array technology. It can interrogate large structural areas from a single location using ultrasonic guided Lamb and Rayleigh waves generated by tuned piezoelectric wafer active sensors (PWAS) that are permanently attached to the structure. This paper brings together several aspects of the implementation and applicatio...

This presentation discusses different Zakharenko waves (ZWs) such as the non-dispersive ZWs, dispersive leaky ZWs, slow surface ZWs and ultrasonic surface ZWs, as well as their possible applications. The nondispersive Zakharenko waves can be found in complex systems such as different layered and quantum systems. Existence examples of the non-dispersive Zakharenko waves in both fundamental modes...