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KAPUSTINA, MCSKIMIN, 0. A. Investigation of ultrasonic absorption in a 3-component system. Akust. Zh., 8, No. 3, p. 314 (1962) An experimental inve...

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KAPUSTINA,

MCSKIMIN,

0. A.

Investigation of ultrasonic absorption in a 3-component system. Akust. Zh., 8, No. 3, p. 314 (1962) An experimental investigation was made of ultrasonic absorption in a 3-component system consisting of a suspension of colloxilin in water that contained air bubbles of diameter The occurrence of similar systems in 0.0003-O-04 cm. practical work, which made this enquiry necessary, is indicated. On the assumption that the absorption processes between water and colloxilin and between water and air bubbles were independent, an estimate was obtained of the coefficient of absorption. The absorption was measured experimentally, at frequencies ranging from 16.2-3,000 kc/s, by an acoustic interferometric method. A package emitter, consisting of two metal discs between which was a plate or stick of barium titanate was used as the source of sound. The amplitude of the variable sonic pressure in the standing wave at different distances from the source was measured with a barium titanate sound receiver. Hence, by means of the formula 3.48f 0: = ~ nc

tanh-l

(P,,,

P,i,,)

Pmin are respectively where f, c, P,,,, phase velocity and the nodal and antinodal standing wave, the coefficient of absorption This agreed with the theoretical estimate assumption that the two processes of independent. (Ultrasonics 1963, abstract 22)

the frequency, pressures of the was calculated. obtained on the absorption are

R. F., and SKOBOV, v. G. On the theory of the amplification of ultrasound by semi-metals in electric and magnetic fields. Zh. Eksperimental’noi i teor. Fiz., 43, No. 4 (IO), p. 1496 (1962) The authors investigate the passage of ultrasound through electric and magnetic fields and establish the following results: (1) Interaction of conduction electrons with the sound wave leads to the amplification of the wave provided that the electron drift velocity in the direction of propagation of the ultrasound exceeds the velocity of sound. (2) The amplification factor is often significantly increased by the presence of a strong magnetic field perpendicular to the electric field. Numerous examples of the resonance dependence of the amplification factor on the strength of the fields are considered. (11 references) (Ultrasonics 1963, abstract 23) KARAZINOV,

KAY,

L.

Auditory perception and its relation to ultrasonic blind guidance aid. Symposium on practical electronic aids for the handicapped, London (1962). A portable guidance aid for blind people which uses frequency modulation echo-location principles has been tested on a small group of people with encouraging results. Both pulsed and continuous wave frequency modulated transmission were used, but the best results have been achieved with continuous wave methods. (Ultrasonics 1963, abstract 24)

H. J.

The measurement of ultrasonic wave velocities in solids in the frequency range 100-500 MC/S. J. Acoust. Sot. Amer., 34, No. 4, p. 404 (1962) Apparatus for measuring ultrasonic wave velocities and hence elastic moduli by phase comparison methods at frequencies as high as 500 MC/S is described. Gated harmonic generators for providing pulse modulated r.f. of accurately known carrier frequency and circuits for the electrical coupling to resonant quartz-crystal transducers are discussed. Application to measurements on small specimens with illustrative data for cadmium telluride is dealt with. (14 figures) (Ultrasonics 1963, abstract 26) MALECKI,I.

New problems in ultrasonic non-destructive testing of materials. Wiss. Z. Hochsch. Schwermaschinenbau Magdeburg, 5, No. 1, p. 77 (1962) The problems of N.D.T. have shifted in emphasis from purely technical difficulties to standardization of the methods of testing and calibration. Automation of testing, methods of coupling and visual display may soon be important. Some Japanese test pieces are described. (Ultrasonics 1963, abstract 27) v. v., and METELKIN, I. v. Surface purity and the precision of holes in ultrasonic machinery. Mashinostroitel’, 2, p. 29 (1962) The authors consider the four factors affecting surface quality in general, namely, the amplitude of oscillation of the instrument, the size of the abrasive particles, the strength characteristics of the material being machined and the method of machining. They state that there are two groups of factors which affect the precision of ultrasonic machining, those which affect all methods of mechanical machining and those which affect only this particular method. In the second group are the size of the abrasive particles, the abrasion of the cutting part of the instrument and the depth of the hole cut. The magnitudes of the effects are investigated and the results are given. (5 tables and 5 figures) (Ultrasonics 1963, abstract 28)

METELKIN,

and YAKOVLEV,L. A. Some features of the propagation and reflections of ultrasound beams in mono-crystals. Akust. Zh., 8, No. 1, p. 99 (1962) A simple derivation is given of equations which permit the direction of sound beams in crystals to be found; reflection from a free boundary is considered. The possibility is demonstrated of using a shadow method of making the sonic field visible and of using a pulse method of mutiple reflections for the experimental observation of the paths of the beams in the crystals. Numerical calculations of the directions of the beams in quartz give a good coincidence with experiment. (1 table, 7 figures and 8 references) (Ultrasonics 1963, abstract 29) MERKULOV,L.G.,

and YAKOLDEV,L. A. Crystal ultrasonic delay line with application of the phenomenon of beam deviation. Akust. Zh., 8, No. 2, p. 199 (1962) The possibility is considered of making an ultrasonic delay line from a crystal. The length of the acoustic path with multiple reflection is increased by using the phenomenon of deviation of the sonic beam from the wave normal, which permits the sound carrier to be given the simpler form of a rectangular parallelopiped. The calculation is made, and the results given of the experimental investigation of a sound carrier of crystalline quartz. A method of excitation away from resonance was used for the generation of very high ultrasonic frequencies. An equation connecting the amplitude of the displacement in the sonic wave with the magnitude of the electric field is deduced. (3 figures and 5 references) (Ultrasonics 1963, abstract 30) MERKULOV,L.G.,

KRAUTKRAMER,J.

Ultrasonic valve testing in Europe and the attitude of technical control authorities. Non-destructive Testing, 20, No. 5, p. 319 (1962) The author briefly surveys ultrasonic inspection both in Europe and the U.S.A. and enumerates some of the factors influencing the reliability of results. The advantages of manual and other methods of testing are compared and the various types of probe are discussed. The problem of flaw location has largely been overcome but evaluation of the size and type of defect and the interpretation of its significance is closely connected with the training of personnel and remains a problem. (Ultrasonics 1963, abstract 25:)

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