Showing papers in "Ultrasonics in 1979"

TL;DR: In this article, it is shown that the L(0, 1) mode, which is comparable to the A0 Lamb wave mode in flat plate, can be generated with acceptable efficiency.

TL;DR: In this article, a theoretical and experimental study of ultrasonic plate waves in machine-made paper is described, where the paper is assumed to behave as a homogeneous orthotropic plate.

TL;DR: In this article, a medical ultrasound device using a Golay code was proposed and investigated theoretically, enabling the spread energy method to be used to help overcome the restraints of the parameters of resolution, peak power and penetration.

TL;DR: Ultrasonic attenuation in fresh and 5% formalin fixed beef skeletal muscle has been measured, as a continuous function of frequency, in the range 1-8 MHz, for muscle fibre orientations both parallel and normal to the direction of propagation.

TL;DR: In this paper, a review of available numerical techniques is presented and this is followed by discussion of a series of models which use finite difference methods to predict the reflected and transmitted signals from wide band pulses of ultrasonic Rayleigh waves incident on various surface-breaking features.

TL;DR: In this article, the authors consider the mechanisms by which two of the ultrasonic pulses of importance in the diffraction technique are produced and compare the current theoretical situation with experimental measurements taken during the period of this work.

TL;DR: A medical ultrasound device using a Golay code is proposed and investigated theoretically and the code enables the spread energy method to be used to help overcome the restraints of the parameters of resolution, peak power and penetration.

TL;DR: The development of a method for easily measuring haemodynamics in the thoracic region using an oesophageal probe will provide an essentially non-invasive method for the assessment of cardiac function and the nature of blood vessels in that region.

TL;DR: The most successful transducer-bond combinations were PZT-5A with a solder bond and lithium niobate with either a ceramic or gold-indium bond for use up to 400°C as mentioned in this paper.

TL;DR: In this paper, the authors present a high voltage scr pulse generator that is useful for testing highly attenuative materials in the pulse echo mode, and demonstrate a practical circuit design that can operate from a supply voltage of 1000 V at a pulse repetition frequency of 1000 Hz.

TL;DR: An experimental ultrasonic sonar for use as a sensory aid with blind children is described, which has two features, a variable range code and an automatic level control, which make the device very versatile in a wide variety of environments.

TL;DR: In this article, the authors measured attenuation and velocity of bulk longitudinal ultrasonic waves during the commercial suspension polymerization of vinyl chloride in the frequency range of a few hundred kHz to one MHz.

TL;DR: Three-dimensional display method by which the shape of an abnormal tissue, say, a breast tumour is represented as a line picture on a cathode ray tube (crt) by using image processing techniques such as smoothing and Laplacian.

TL;DR: In this paper, the authors investigated the most important sources of coupling in transducer arrays for ultrasonic imaging devices and proposed means for reducing this coupling. But no simple analytical calculation can be performed, and diagrams have been established that enable evaluation of the electrical coupling against the dimensional characteristics of the array.

TL;DR: In this paper, the authors demonstrate the comprehensive way in which the Unit Impulse Response technique can be used to evaluate and calibrate thickness mode piezoelectric transducers and the ultrasonic probes made from these transducers.

TL;DR: A new pair of sequences whose cross-correlation values are zero except for the peak value are presented and a new modulation method for an ultrasonic Doppler flowmeter with high sensitivity utilizing these sequences is presented.

TL;DR: In this article, a model for calculating acoustic emission amplitudes is presented based upon a method of describing the stress waves from a local change of an inelastic strain, which takes into account the limitations of normal measuring equipment.

TL;DR: In this paper, a description of methods and the arrangement for the experimental study of an ultrasonic field and displacements of piezoelectric transducer distribution using optical holography is presented.

TL;DR: In this article, a technique for the optical display of three-dimensional ultrasonic fields, involving the visualization of thin sections of the field within a layer of suitable photoelastic solid, such as polyurethane rubber, is presented.

TL;DR: In this paper, a theoretical model is developed and experimental proof of the validity of the model is presented, which is explained in terms of constructive and destructive interference due to specimen geometry.

TL;DR: In this article, it has been shown that ultrasonic transmission across an adhesive-bonded joint changes as the adhesive film progressively cures, and the time-transmission plot exhibits a characteristic curve, which appears to be indicative of the curing time.

TL;DR: A new processing technique is introduced that provides the required delay first by properly phasing the echo carrier, and successively by delaying the echo envelope based on a new analogue sampled-data delay-line.

TL;DR: Two techniques for tissue characterization by ultrasonic analysis are described and it is examined how it is possible to estimate the surface roughness and the average spatial periodicity d characteristic of the tissues by calculating the Fourier transform or the autocorrelation function of I (theta).

TL;DR: In this article, the acoustic load dependency of the electroacoustic efficiency in the electrostrictive transducer is derived theoretically and measured experimentally, and the results show that there is an optimum acoustic load resistance which maximizes the electroACoustic efficiency.

TL;DR: The application of Schlieren ultrasonic techniques to the visualization of delaminations in composite materials is described and discussed in this article, where it is shown that this technique can provide an efficient, practical, non-destructive testing method.

TL;DR: In this article, a new approach for estimating the intermolecular free-length as a function of pressure and temperature as low as 0.5 K for pure liquids was proposed.

TL;DR: In this paper, a method for determining the compressibility coefficient and relative bulk modulus, and also the density of liquid petroleum products as function of temperature and pressure in the range of −50 to 80°C and 10 to 2.5 × 108Pa is presented; the accuracy of the method is respectively 0.74, 0.43% and 0.39%.

TL;DR: The depth perception obtained from the reconstructed image using the fly's-eye lens is analysed and an optical configuration that maximizes the depth perception is devised.