Showing papers in "Ultrasonics in 1985"

TL;DR: In this paper, the results of jet and vortex ring formation obtained mainly with spark-and laser-produced bubbles are reported and demonstrated in a series of frames, using high speed photography in conjunction with some suitable bubble production mechanism to get rid of the statistical appearance of bubbles encountered in ultrasonic cavitation.

TL;DR: In this article, a laser technique for generating convergent acoustic waves is described, and the optically probed Rayleigh wave in the centre of convergence shows an amplification factor of the order of 20 with respect to a collimated surface wave.

TL;DR: In this article, the authors reviewed contemporary ideas on the nature of cavitation, including the general theories of sonoluminescence and sonochemical reactions, the origin, stability, and splitting of Cavitation bubbles, the dynamics of the cavitation field evolution, the peculiarities of cavitations at low intensity and low-frequency acoustic oscillations, the sonoline quenching effect, and some questions on the energetics of the Cavitation fields are discussed.

TL;DR: The needle hydrophone as discussed by the authors is a piezoelectric polymer hydrophone for the frequency range above 1 MHz, which consists of a needle, coated with a thin layer of polyvinylidene fluoride.

TL;DR: By building several of the theoretically investigated transducer configurations it is shown that theory and experiment agree well, and the properties of a transducers can be predicted to a good approximation before its experimental realization.

TL;DR: In this paper, the authors describe the fundamentals, design criteria and electronic structure of a new frequency control system to keep permanently at resonance high Q ultrasonic transducers whose mechanical resonance band may vary within wide limits under normal operating conditions.

TL;DR: In this paper, an expression for the ultrasonic velocity of the fundamental horizontally polarized shear (SH) wave propagating in the plane of the plate at an angle θ to the rolling direction is given.

TL;DR: In this paper, a model for the analysis of thickness-mode piezoelectric transmitters under practical operating conditions is presented, where important parameters are highlighted and their influence on transducer response is demonstrated using a number of simulation diagrams.

TL;DR: The vibrational behaviour of Alberich-type absorbers is reviewed once more in this article, where two types of resonance mechanisms are known to be present in such layered configurations: radial motion of the hole wall and the drum-like oscillations of the cover layer.

TL;DR: In this paper, the effect of grating lobes on the echo image and the mismatch of the matching layer is discussed and suggestions are made for the design of linear and phased array transducers considering the abovementioned aspects.

TL;DR: In this paper, a stochastic series is presented by which a typical AE signal detected by resonant transducers can be described, and the series is then analyzed numerically by a simulated system for AE amplitude distribution analysis.

TL;DR: The so-called KLM-model for ultrasonic transducers is employed to optimize transducer design and some new performance characteristics are defined which change monotonically with design parameters.

TL;DR: A wide variety of transducer shapes and applications exist in the field of diagnostic ultrasound as mentioned in this paper, and a qualitative way the most relevant parameters of these materials, a state of the art judgement may be made about their applicability in diagnostic ultrasound.

TL;DR: The residual stresses in a shrink-fit specimen were measured ultrasonically, using shear-horizonal (SH) waves transmitted and received by noncontacting electromagnetic acoustic transducers as discussed by the authors.

TL;DR: In this article, the importance of knowing the material's single-crystal elastic constants, the C ij s, is explained for studying welds ultrasonically, and some guidelines are given for estimating them from polycrystalline elastic constants such as Young's modulus and the shear modulus.

TL;DR: It is concluded that a direct interaction between ultrasound and the catalytic functioning of individual enzyme molecules is unlikely to be the primary step in any acousto-biological interaction, and that this primary interaction appears to be occurring at a higher level of organizational complexity.

TL;DR: In this article, the Riccati equation was used to determine the transverse acoustic impedance of viscous films and for inhomogeneities due to healing lengths and van der Waals forces near the solid/fluid interface.

TL;DR: In this paper, two ultrasonic methods are proposed to measure the crack location and the crack height for vertical and inclined defects, which do not depend on knowing the probe angle, which varies from material to material being inspected.

TL;DR: In this paper, an explanation for the phase errors is offered, and a new demodulation method is described, which eliminates these errors, and is used for cross correlation flowmeters using clamp-on ultrasonic transducers.

TL;DR: An ultrasonic signal processor is described which analyses information from conventional echo sounders fitted to small craft and permits these to be used in such a way as to augment, confirm and extend the professional experience of the individual fisherman.

TL;DR: A layered model was used to calculate total attenuation of ultrasound pulses as they passed through tissue layers to an organ site, thus enabling calculation of in situ intensities from free-field transducer emissions.

TL;DR: In this paper, the authors used ultrasonic, hardness and x-ray densitometric methods to predict the wood quality of Douglas fir sapwood from pruned and control trees.

TL;DR: In this paper, a model system consisting of a thin layer of vacuum-deposited metallic aluminium on a glass microscope slide was developed to demonstrate the effectiveness of cavitational activity (occurring within the cooling water supply of a dental ultrasonic descaler operating at 25 kHz) in the removal of particulate matter from solid surfaces.

TL;DR: In this article, the authors considered the application of the acoustic birefringence method to generalized plane stress states, where the thickness-averaged values of the shear and normal stresses are sought.

TL;DR: In this paper, an optical heterodyne method is presented for measuring the Raman-Nath parameter of ultrasound, where a light beam passes through a phase grating induced by ultrasound and then is recombined with another beam of light at a shifted frequency.

TL;DR: In this article, a new technique was developed for carrying out real-time ultrasound reflection tomography using cylindrically diverging beams with highly damped broadband probes, where the carrier information of the pulse was dispensed with and only the peak of the rectified rf pulse and its corresponding time of arrival were used for the reconstruction.

TL;DR: In this article, a method of flaw characterization based on time domain analysis of the diffracted sound field from a flaw when irradiated by short ultrasonic pulses is described, and the echo formation mechanism developed by Freedman has been utilized to predict the return pulse pattern.

TL;DR: The general conclusion is that electronic sector scanners may have a considerably improved cost/benefit ratio in the near future and thereby will become the leading systems for echocardiography.

TL;DR: In this article, a method for determining the size and size distribution of cylindrical particles is described based on the fact that rigid particles, when they impinge on each other, emit acoustic waves whose frequencies are related to the particle size and the size distribution.