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Ultrasonic probes: Ultrasonic inspection devices
Resonance matching in thin transition layers Aranovich, V. B., Prudov, I. A. Vol 17 No 4 (April-June 1972) pp 438-443 A technique of matching acoustic impedances at an interface, based on the utilization of resonance in a system comprising two transition layers of small thickness, is investigated. The matching efficiency is estimated for the cases of semi-infinite media and half-wave receiving-transmitting transducers at near-resonance frequencies. The theoretical results are obtained by the method of equivalent circuits in the one dimensional approximation, the matching resonator being represented as a system having lumped mass and compliance. Experimental data has been obtained for half-wave piezoelectric ceramic transducers in water and air, at atmospheric pressure.
MATERIALS
EVALUATION
Ultrasonic examination of welds: comparison of ASME and AWS procedures McGaughey, W. C. Vol 30 No 2 (February 1972) pp 44-48 Correlation of pulse-echo measurements with tensile strength of diffusion bonded joints Regalbuto, J. A. Vol30 No 3 (March 1972) pp 66-72 A simple mathematical model is constructed to calculate tensile strength of diffusion bonded joints from pulse-echo and attenuation measurements. Experimental data is presented which agrees well with the theoretical results. Attenuation, contamination and signal-to-noise ratio effects are discussed.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Multipath summability in ray-theory intensity calculations in the real ocean Neubert, J. A. Vol51 No 1 Part 2 (January 1972) pp 310-322 The conventions1 ray-theory intensity relation is extended to permit consideration of partial coherence in multipath problems by looking at the stochastic nature of microfluctuations. The partial coherence factor is shown to be a function of the curvilinear range, the frequency and the oceanographic conditions. A practical estimate for the standard deviation el of the intensity about its expected value is found; olis shown to depend on the partial coherence factor and to saturate as this factor approaches zero. Measured discrimination of boundary-layer pressure fluctuations by round, square and rectangular transducers Recine, E. C. Vol51 No 1 Part 2 (January 1972) pp 369-377 Pressure fluctuations obtained in a turbulent air pipe flow facility were measured using 19 flush-mounted transducers that varied in size and shape. Good agreement
ULTRASONICS.
JULY 1972
was found between experimental data and theoretical predictions. In the mid-frequency range, transducers that had their longest dimension parallel to the flow produced the greatest discrimination against pressure fluctuations. At high frequencies, the response became a function of size and independent of shape, as predicted. Performance degradation of deep-ocean transducers using onion-skin paper for acoustic decoupling Haan, D. E. Vol51 No 1 Part 2 (January 1972) pp 290-294 The acoustic decoupling behaviour of onion-skin paper is examined with emphasis on sonar transducer applications. Non-linear changes in the sound velocity of onion-skin paper with pressure are used to predict the degradation of both frequency and directional response. These results are obtained by computer analysis of a longitudinal-vibrator equivalent circuit. The results are in reasonable agreement with the measured characteristics of a specific transducer configuration. Acoustically induced gas bubble growth Skinner, L. A. Vol51 No 1 Part 2 (January 1972) pp 378-382 The diffusion problem governing gas bubble growth in oscillatory pressure fields, including growth through reasonance size, is solved by superposition of two sub-problems. Approximate solution of the growth-rate equation is shown to be independent of resonance behaviour details.
PATENTS Hightemperature ultrasonic device Bell Telephone Labs Inc US patent 3599123 (1971) filed 24 September 1969 Certain gold alloys, containing from about 12 to about 67% indium, when used in ultrasonic bonds, have been found to permit the operation of fused silica de$ty lines at temperatures from 200-550 C. This results in at least a 50% increase in frequency of acoustic waves transmitted for a given loss level as compared with room temperature operation. Electron-phonon resonator Wojskow Akademia Techniczna in Jaroslowa Dabrowskiege UK patent 1247622 (1971) filed 3 January 1969 Electra-acoustic transducer plastic diaphragm AKG Akustische & kino-Gerate GmbH UK patent 1246253 (1971) tiled 16 January 1970 Acousto-optic devices using lead molybdate and related compounds Bell Telephone Labs Inc US patent 3617931 (1971) fded 5 May 1969 Acousto-optic devices dependent for their operation on lead molybdate and related compounds show efficiencies comparable to that of devices made from alpha-iodic acid and superior to that of devices constructed of earlier materials such as lithium niobate.
Acoustic direction-finding Fried Krupp GmbH UK patent 1262900 (1972) fled 31 July 1968 The device calculates the angle of incidence of a sound wave-front, of predetermined frequency, relative to two spaced transducer groups, from the phase shift needed to compensate for the pl.ase angle between the output voltages of the two groups. Acoustic holography Holotron Group UK patent 1263093 (1972) fled 6 March 1968 Viewing optics are focused on the detecting surface itself to reduce the dependence of image resolution on the size of light source, and on irregularities in the ultrasonic detecting surface. Acoustic lenses Holotron Corp UK patent 1263749 (1971) filed 20 May 1968 An acoustic lens consists of two liquids having differing acoustic indices of refraction relative to air, and a stretched and curved synthetic polymeric film separating the liquids. Ultrasonic inspection devices Branson Instrument Inc UK patent 1264424 (1972) filed 23 May 1968 A pulse-echo device selects and indicates the shortest pulse transit-time in a series of measurements to prevent spurious readings due to increasing pulse propagation times when the temperature of a coupling medium between the transducer probe and a hot test object rises. Ultrasonic probes: ultrasonic inspection devices Shurtronics Corp UK patent 1267208 (1972) filed 26 September 1968 An ultrasonic probe has a generally cylindrical transducer element loosely retained by guides to permit limited radial axial movement of the element. Piezoelectric devices Minnesota Mining & MFG Co UK patent 1268141 (1972) filed 27 January 1969 Delay lines make use of transducer or delay elements cut from a single crystal of wurzite zinc oxide. The element has maior faces at right-angles to an axis which makes an angle of between 13 and 53 degrees with the crystallographic c-axis. Acoustic detection of gas bubbles in blood National Research Development Corp UK patent 1268640 (1972) filed 31 May 1968 Acoustic delay lines Motorola Inc UK patent 1268853 (1972) filed 26 August 1969 A delay line comprises a piezoelectric crystal shaped as a tube. The mean diameter of the
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MATERIALS
EVALUATION
Ultrasonic examination of welds: comparison of ASME and AWS procedures McGaughey, W. C. Vol 30 No 2 (February 1972) pp 44-48 Correlation of pulse-echo measurements with tensile strength of diffusion bonded joints Regalbuto, J. A. Vol30 No 3 (March 1972) pp 66-72 A simple mathematical model is constructed to calculate tensile strength of diffusion bonded joints from pulse-echo and attenuation measurements. Experimental data is presented which agrees well with the theoretical results. Attenuation, contamination and signal-to-noise ratio effects are discussed.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA Multipath summability in ray-theory intensity calculations in the real ocean Neubert, J. A. Vol51 No 1 Part 2 (January 1972) pp 310-322 The conventions1 ray-theory intensity relation is extended to permit consideration of partial coherence in multipath problems by looking at the stochastic nature of microfluctuations. The partial coherence factor is shown to be a function of the curvilinear range, the frequency and the oceanographic conditions. A practical estimate for the standard deviation el of the intensity about its expected value is found; olis shown to depend on the partial coherence factor and to saturate as this factor approaches zero. Measured discrimination of boundary-layer pressure fluctuations by round, square and rectangular transducers Recine, E. C. Vol51 No 1 Part 2 (January 1972) pp 369-377 Pressure fluctuations obtained in a turbulent air pipe flow facility were measured using 19 flush-mounted transducers that varied in size and shape. Good agreement
ULTRASONICS.
JULY 1972
was found between experimental data and theoretical predictions. In the mid-frequency range, transducers that had their longest dimension parallel to the flow produced the greatest discrimination against pressure fluctuations. At high frequencies, the response became a function of size and independent of shape, as predicted. Performance degradation of deep-ocean transducers using onion-skin paper for acoustic decoupling Haan, D. E. Vol51 No 1 Part 2 (January 1972) pp 290-294 The acoustic decoupling behaviour of onion-skin paper is examined with emphasis on sonar transducer applications. Non-linear changes in the sound velocity of onion-skin paper with pressure are used to predict the degradation of both frequency and directional response. These results are obtained by computer analysis of a longitudinal-vibrator equivalent circuit. The results are in reasonable agreement with the measured characteristics of a specific transducer configuration. Acoustically induced gas bubble growth Skinner, L. A. Vol51 No 1 Part 2 (January 1972) pp 378-382 The diffusion problem governing gas bubble growth in oscillatory pressure fields, including growth through reasonance size, is solved by superposition of two sub-problems. Approximate solution of the growth-rate equation is shown to be independent of resonance behaviour details.
PATENTS Hightemperature ultrasonic device Bell Telephone Labs Inc US patent 3599123 (1971) filed 24 September 1969 Certain gold alloys, containing from about 12 to about 67% indium, when used in ultrasonic bonds, have been found to permit the operation of fused silica de$ty lines at temperatures from 200-550 C. This results in at least a 50% increase in frequency of acoustic waves transmitted for a given loss level as compared with room temperature operation. Electron-phonon resonator Wojskow Akademia Techniczna in Jaroslowa Dabrowskiege UK patent 1247622 (1971) filed 3 January 1969 Electra-acoustic transducer plastic diaphragm AKG Akustische & kino-Gerate GmbH UK patent 1246253 (1971) tiled 16 January 1970 Acousto-optic devices using lead molybdate and related compounds Bell Telephone Labs Inc US patent 3617931 (1971) fded 5 May 1969 Acousto-optic devices dependent for their operation on lead molybdate and related compounds show efficiencies comparable to that of devices made from alpha-iodic acid and superior to that of devices constructed of earlier materials such as lithium niobate.
Acoustic direction-finding Fried Krupp GmbH UK patent 1262900 (1972) fled 31 July 1968 The device calculates the angle of incidence of a sound wave-front, of predetermined frequency, relative to two spaced transducer groups, from the phase shift needed to compensate for the pl.ase angle between the output voltages of the two groups. Acoustic holography Holotron Group UK patent 1263093 (1972) fled 6 March 1968 Viewing optics are focused on the detecting surface itself to reduce the dependence of image resolution on the size of light source, and on irregularities in the ultrasonic detecting surface. Acoustic lenses Holotron Corp UK patent 1263749 (1971) filed 20 May 1968 An acoustic lens consists of two liquids having differing acoustic indices of refraction relative to air, and a stretched and curved synthetic polymeric film separating the liquids. Ultrasonic inspection devices Branson Instrument Inc UK patent 1264424 (1972) filed 23 May 1968 A pulse-echo device selects and indicates the shortest pulse transit-time in a series of measurements to prevent spurious readings due to increasing pulse propagation times when the temperature of a coupling medium between the transducer probe and a hot test object rises. Ultrasonic probes: ultrasonic inspection devices Shurtronics Corp UK patent 1267208 (1972) filed 26 September 1968 An ultrasonic probe has a generally cylindrical transducer element loosely retained by guides to permit limited radial axial movement of the element. Piezoelectric devices Minnesota Mining & MFG Co UK patent 1268141 (1972) filed 27 January 1969 Delay lines make use of transducer or delay elements cut from a single crystal of wurzite zinc oxide. The element has maior faces at right-angles to an axis which makes an angle of between 13 and 53 degrees with the crystallographic c-axis. Acoustic detection of gas bubbles in blood National Research Development Corp UK patent 1268640 (1972) filed 31 May 1968 Acoustic delay lines Motorola Inc UK patent 1268853 (1972) filed 26 August 1969 A delay line comprises a piezoelectric crystal shaped as a tube. The mean diameter of the
191