ARTICLES

Ultrasonic Domestic Gas Meter
Noel Bignell

Three Dimensional Medical Ultrasound
S. W. Hughes

Ultrasound Calibration at the National Measurement Laboratory
Adrian J. Richards and Adam P. Stirling

Ultrasound Guided Waves for Inspection of Bonded Panels
D. C. Price, B. J. Martin and D. A. Scott

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ULTRASONIC DOMESTIC DOMESTIC GAS METERS

Noel Bignell
CSIRO Telecommunications and Industrial Physics
Lindfield NSW 2070

Vol. 27, No. 3 pp 77-81 (1999)
ABSTRACT: Different ultrasonic domestic gas meters and the transducers used are discussed. They all measure a gas velocity with a transit time method. Time measurement techniques include repeated transmission and phase measurement. The propagation of the acoustic energy in the duct of the meter is in the form of modes and these can cause waveform changes and timing errors, which are discussed. The relationship of the velocity measured to the flow is not simple and various means are used to determine the flow from the velocity. This significance of delays and proper reciprocal operation is discussed.

THREE-DIMENSIONAL MEDICAL ULTRASOUND

S. W. Hughes
Queensland University of Technology
Brisbane, QLD 4001

Vol. 27, No. 3 pp 83-87 (1999)
ABSTRACT: A number of groups around the world are working in the field of three dimensional (3D) ultrasound (US) in order to obtain higher quality diagnostic information. 3D US, in general, involves collecting a sequence of conventional 2D US images along with information on the position and orientation of each image plane. A transformation matrix is calculated relating image space to word space. This allows image pixels and region of interest (ROI) points drawn on the image to be displayed in 3D. The 3D data can be used for the production of volume or surface rendered images, or for the direct calculation of ROI volumes.

ULTRASOUND CALIBRATION AT THE NATIONAL MEASUREMENT LABORATORY.

Adrian J. Richards and Adam P. Stirling
Ultrasound Standards, National Measurement Laboratory
Division of Telecommunications and Industrial Physics, CSIRO Lindfield.

Vol. 27, No. 3 pp 89-93 (1999)
ABSTRACT: The National Measurement Laboratory (NML) has had interactions in ultrasound ranging from the medical (therapy and diagnostic), non-destructive testing/evaluation (NDT/E) to high power cleaning and sonic processing. A present emphasis is in therapy ultrasound. In this area there is a problem with poorly calibrated ultrasound therapy machines either delivering a dangerous amount of ultrasound or so little that it is of no clinical benefit. A traceability chain is required from the clinical user of the ultrasound therapy machine to national standards. A portable power standard (PPS) is presently being designed to enable the traceability to occur. Just as importantly the associated advisory publications are being formulated to enable its deployment in the traceability chain. The next major effort in ultrasound standards is expected to be NDT/E for Australian and New Zealand industry. A review of what is required for standards support in the NDT/E community is to be undertaken.

ULTRASOUND GUIDED WAVES FOR INSPECTION OF BONDED PANELS

D. C. Price, B. J. Martin and D. A. Scott
CSIRO Division of Telecommunications and Industrial Physics
Lindfield, NSW

Vol. 27, No. 3 pp 95-101 (1999)
ABSTRACT: This paper describes the propagation of "leaky" guided ultrasonic waves in layered planar structures, typically of adhesively bonded metal panels, when they are immersed in water. An outline of the physics of these waves is given, and the way in which they can be used to detect bond defects is indicated.