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...

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...

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...

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...

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...

Background: Recently, ultrasonic neuromodulation research has been an important and interesting issue. Ultrasonic neuromodulation is possible by the use of low-intensity transcranial focused ultrasound (tFUS) to stimulate or inhibit the neural structures. The primary capability of this method is the improvement in the treatment progress of certain neurological and psychiatric disorders noninvas...

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...

| For large aerospace structures, it is extremely important to detect faults, and non-destructive testing is the only practical way to do it. Based on measurements of ultrasonic waves, Eddy currents, magnetic resonance, etc., we reconstruct the locations of the faults. The best (most eecient) known statistical methods for fault reconstruction are not perfect. We show that the use of expert know...