Kinetics of ultrasonic chemical reactions

A d i s p e r s i o n relation is derived for ultrasound in an a n i s o t r o p i c p i e z o e l e c t r i c s e m i c o n d u c t o r in the p r e sence of an alternating e l e c t r i c field whose frequency is much higher than the collision frequency of elect r o n s with impurities, phonons, etc. When the field f r e q u e n c y is much higher than the u l t r a s o n i c frequency the coefficient of absorption of ultrasound by conduction e l e c t r o n s is an oscillating function of the field amplitude. By m e a s u r i n g the oscillation period for v a r i o u s relative d i r e c t i o n s between the field v.ector and u l t r a s o n i c wave vector it is possible to determine all the components of the effective m a s s tensor. D e t e r m i n a t i o n of the equivalent p a r a m e t e r s of t r a n s d u c e r s f r o m impedance or a d m ~ c e phase di~5.rams Lovyagin, A. V. Vol 16, No 3 ( J a n u a r y - M a r c h 1971) pp357-360 l~inet~cs of ultrasouie c h e m i c a l r e a c t i o n s Margulis, M. A. Vol 16, No 3 ( J a n u a r y - M a r c h 1971) pp361-371 The fundamental experimental r e s u l t s of different r e s e a r c h e r s on the kinetics of c h e m i c a l r e a c t i o n s stimulated by u l t r a s o n i c waves, as well as the kinetic c h a r a c t e r i s t i c s of those reactions, are analyzed. Kinetic equations a r e derived for r e a c t i o n s o c c u r r i n g in solutions with the participation of r a d i c a l s that are products of the u l t r a s o n i c decomposition of water molecules. Calculation of the t h i r d - o r d e r e l a s t i c constants f r o m resultB v~ u l t r a s o n i c m e a s u r e m e n t s Sekoyan, S. S. Vol 16, No 3 ( J a n u a r y - M a r c h 1971) pp377-380 Equations are derived for calculating the values of the t h i r d - o r d e r elastic constants of an i s o t r o p i c m a t e r i a l f r o m the r e s u l t s of m e a s u r e m e n t s of the propagation velocities of elastic waves in the m a t e r i a l when it is subjected to homogeneous static s t r e s s e s . Unlike the well-known equations of Thurston and Brugger, the equations obtained here involve c e r t a i n t h e r m a l c h a r a c t e r i s t i c s of the m a t e r i a l . Intersection of the ultrasonic v e l o c i t y c u r v e s for substances in the liquid and vapour p h a s e s near the c r i t i c a l point Nozdrev, V. F., Petukhov, P. S. Vol 16, No 3 ( J a n u a r y - M a r c h 1971) pp405-407 Conference on solid state tfltrasonics Propopenko, G. I. Vol 16, No 3 ( J a n u a r y - M a r c h 1971) pp412-415

MATERIALS EVALUATION

A proposed resolution test for ultrasonic angle beam probes Chapman, H. Vol 29, No 1 (January 1971) p p l - 7 R e s u l t s are p r e s e n t e d of a study on an experimental verification of a resolution test for u l t r a s o n i c angle beam probes. A t a r g e t is proposed consisting of a group of three small, in-line holes with finished bore. The interaction between the pitch of the holes and the attitude of the l a r g e s t group to the sound beam is shown. Test blocks are proposed that maintain a

c o m m o n p r o b e - t o - t a r g e t distance and take into account the frequency of the sound as well as the attitude of the t a r g e t to the sound beam. Other models of test blocks f r o m the literature a r e c o m p a r e d with the p r o posed blocks. Acoustic e m i s s i o n monitoring s y s t e m for detection of c r a c k s in a c o m p l e x structure Nakamura, Y. Vol 29, No 1 (January 1971) ppS-12 A description is given of various types of ultrasonic d i r e c t - r e a d i n g wall-thickness m e t e r s . The implications of the type of instrument as r e g a r d s the indication e r r o r are discussed. The behaviour of different i n s t r u m e n t - p r o b e combinations can be c o m p a r e d with the aid of d i a g r a m s showing the depth Characteristic and the useful operating area. The influence of t e m p e r a t u r e on probe and object is analyzed. Suggestions are made with r e s p e c t to minimum r e q u i r e m e n t s for m e t e r s to be used in the p r o c e s s industry.

BRITISH P A T E N T S

Acoustic signalling Raytheon Co B r i t i s h Patent 1, 214, 050 (1970) Filed 21 Oct 1968 In a f r e q u e n c y - c o d e d s y s t e m for activating a r e m o t e u n d e r w a t e r device, a r e c e i v e r is a r r a n g e d to respond only to the p r e s e n c e of at least one of two a s s e r t i o n f r e q u e n c i e s and to the absence of other negation frequencies. The s y s t e m will operate a relay, motor, radio t r a n s m i t t e r or valve. A c o u s t i c range-finding P o l a r o i d Corp British Patent 1, 214, 447 (1970) Filed 24 March 1969 A c a m e r a has means for propagating an acoustic signal, m e a n s for r e c e i v i n g a r e f l e c t e d signal, and a m e a n s for focusing the lens s y s t e m according to the reflected signal. The acoustic device has two identical conical horns for t r a n s m i t t i n g and receiving, and is of p a r t i c u l a r application when an object being photographed is moving rapidly, or in dark or poor light conditions. Measuring liquid level e l e c t r i c a l l y European Atomic E n e r g y Community B r i t i s h Patent 1,216, 253 (1970) Filed 17 Sept 1968 Ultrasonic couplings J o s e p h L u c a s (Industries) Ltd British Patent 1, 213,471 (1970) Filed 26 Jan 1968 An ultrasonic tool for pasting e l e c t r i c battery plates c o m p r i s e s an oscillator driven by a t r a n s d u c e r through a velocity t r a n s f o r m e r . The oscillator o p e r a t e s at frequencies up to 24kHz and amplitudes between 1 × 10 -4 and 1 × 10 -2 in. P u l s e generators Compagnie Generate d ' E l e c t r o n i q u e Industrielle Lepanto British Patent I, 213, 717 (1970) Filed 15 March 1968 Modifying a c o u s t i c s Applied Acoustics Ltd B r i t i s h Patent 1, 214, 358 (1970) Filed 17 March 1969 ULTRASONICS July 1971

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