DOMNIKOV, L. The effect of u l t r a s o n i c s on the phosphating p r o c e s s . Metal Finishing, 65, No. 2, p. 55 (1967).

The use of u l t r a s o n i c s in phosphat ing of f e r r o u s m e t a l s p ro - duces s u p e r i o r coat ing and obvia tes the neces s i t y for p r e - l im ina ry sand blast ing. The phosphate coat ings produced in an u l t r a son ic bath at 16-22kHz for 40-60 min a r e l e s s porous, have h igher c o r r o s i o n r e s i s t a n c e , g r e a t e r d i e l ec t r i c s t r eng th and a f i ne r f inish. Best r e s u l t s we re obta ined in so lu t ions of 20 -25g / l i t phosphor ic acid, 38 -42g / l i t zinc monophosphate , 56 -62g / l i t zinc n i t r a t e at 70°C. (2 f igures , 2 tables , 1 r e f e r - ence) (Ul t r a son ics 1967, a b s t r a c t 651)

GARG, A. G. and TAYLOR, A. R. Effec ts of u l t rasound--wi th spec ia l r e f e r e n c e to the ne rvous sys t em. Biomedica l Engineer ing , 2, No. 5, p. 222 (1967).

A review of an investigation to determine the effects of ultrasonics on the nervous system. Thermal, mechanical, chemical and electrochemical effects are summarized. Refe rence is made to biological changes and t h e i r t h e r a - peutic appl icat ions, p a r t i c u l a r l y on the cen t r a l ne rvous s y s - t ems . (49 r e f e r e n c e s ) (U l t r a son ic s 1967, a b s t r a c t 652)

HEFFAN, H. et al Quali ty evaluat ion of m i s s i l e s t r u c t u r e spot welded joints . M a t e r i a l s Evaluat ion, 25, No. 1, p. 15 (1967).

Th i s r e s e a r c h p r o g r a m m e followed a n u m b e r of s t r u c t u r a l f a i l u re s in m i s s i l e s dur ing flight. A s igni f icant n u m b e r of spot welds were found to be s u b s t a n d a r d to an extent that ranged f rom u n d e r s i z e d nuggets to comple te unbonds. In conjunct ion with r ad iograph ic and me ta l log raph ic ana ly s i s new u l t r a son ic t r a n s d u c e r s have been developed, and spec ia l s t anda rds have been devised that a r e thought to give comple te re l i ab i l i ty in the grad ing of spot welds. (6 f igures , 1 table) (Ul t r a son ics 1967, a b s t r a c t 653)

JACOBS, J. E. P e r f o r m a n c e of the u l t r a s o n i c m i c r o s cope . M a t e r i a l s Evaluation, 25, No. 3, p. 41 (1967).

The reso lu t ion of an u l t r a son ic c a m e r a is se t by the th ick- ness of the p i ezoe lec t r i c c r y s t a l and by the acous t ic opt ics . Maximum reso lu t ion is obtained when the incident sound pa t t e rn does not devia te m o r e than 2 ° f rom the beam axis . With p r e s e n t f r equenc i e s (up to approx imate ly 15MHz) the s m a l l e s t r e so lvab le object is approx imate ly 0 .34mm. It is thought that with the advent of the deplet ion l aye r t r a n s d u c e r s f r equenc ie s of up to 3GHz will be able to be used but then the reso lu t ion will be d e t e r m i n e d by the e l ec t ron beam d i a m e t e r which is at p r e s e n t approx imate ly 20~m. (8 f igures , 6 r e f e r - ences) (Ul t rason ics 1967, a b s t r a c t 654)

KORDINA, K. et a l Ultrasonic m e a s u r e m e n t s on r e i n f o r c e d g r a v e l - a g g r e g a t e concre te . Mater ia lp rufung , 9, No. 3, p. 81 (1967).

The u se fu lnes s of u l t r a son ic pulse ve loc i ty m e a s u r i n g methods in the bui lding indus t ry is inves t iga ted . The ve lo - ci ty of u l t r a s o n i c s in conc re t e depends on i t s composi t ion, age, po ros i ty and loading, the method of r e i n fo r cemen t , m i c r o c r a c k s and o ther f a c t o r s and by e l imina t ing some of these v a r i a b l e s the effects of o t h e r s can be de t e rmined . Con- s i s t en t and r ep roduc ib le r e s u l t s have been de r ived for a l l the 27 d i f fe rent c o n c r e t e s inves t iga ted . Method of t e s t ing and the equipment used a r e d e s c r i b e d and it is concluded that th is technique is su i tab le for o n - s i t e quali ty cont ro l app l ica - t ions. (5 f igures , 1 table, 1 r e f e r ence ) (Ul t r a son ic s 1967, a b s t r a c t 656)

KORPEL, A. Visua l i za t ion of the c r o s s - e c h o e s of a sound beam by Bragg d i f f rac t ion of l ight . Applied P h y s i c s Le t t e r s , 9, No. 12, p. 425 (1966).

A novel method of imaging the phase and ampl i tude of the c r o s s - s e c t i o n of an u l t r a s o n i c beam is r epor t ed . Because the phase is r e t a ined in the acous to -op t i ca l conve r s ion p r o c e s s an image of any chosen c r o s s - s e c t i o n of the beam can be obtained by opt ical manipu la t ions and r ep roduced on a s c r e e n or a photographic plate. The appa ra tu s c o n s i s t s of a l a s e r source , 22MHz u l t r a sound g e n e r a t o r in a wa t e r - f i l l ed cel l a t r igh t angles to the l a s e r beam and a col lec t ion of cy l indr ica l l enses . The u l t r a sound f ie ld behind va r ious objec ts shows that at th i s f requency the s m a l l e s t r e s o l v a b l e deta i l i s about 0 . 8 m m but at h igher f r equenc i e s th is technique might f ind appl ica t ion in sound microscopy . (4 f igures , 4 r e f e r e n c e s ) (Ul t r a son ics 1967, a b s t r a c t 657)

IRVING, R. R. Are a l l weld defec ts h a r m f u l ? I ron Age, 199, No. 14, p. 67, (1967).

A c o m p a r i s o n of the advantages and l imi ta t ions in u l t r ason ic , r ad iograph ic , magnet ic and pene t r an t t echniques of non- de s t ruc t i ve tes t ing. Applicat ion to a given s i tuat ion, ease of operat ion, r e l a t i ve cost and p e r m a n e n t r e c o r d s a r e a lso exami - ned. E m p h a s i s is p laced on the i n t e r p r e t a t i o n of the s ign i f i - cance of f laws in ERW pipes des t ined for the power g e n e r a - tion indus t ry . The author concludes that the m u l t i - m e t h o d approach is s t i l l the bes t . (8 f igures , 3 t ab les (Ul t r a son ic s 1967, a b s t r a c t 658)

LITTLEFORD, G. E. Welding e l ec t ron ic d e v i c e s by u l t rason ics . Indus t r i a l E lec t ron ics , 5, No. 3, p. 123 (1967).

U l t r a son ic welding of m i c r o e l e c t r o n i c dev ices is m o r e effi- c ient and p r e c i s e than any o the r known method. U l t r a son ic s can weld many meta l and al loy combina t ions in t h i c k n e s s e s of 100k upwards . A t rue sol id s t a t e me ta l l u rg i ca l bond i s obtained without the appl ica t ion of heat or f luxes and the bonds a r e c o m p a r a b l e in s t r eng th to the pa ren t ma te r i a l . A n u m b e r of examples a re given that have found appl ica t ion in m a s s product ion. (2 tables , 3 f igures ) (Ul t r a son ics 1967, a b s t r a c t 659)

KELPIN, H. and WEIS, O. Sound energy r e c e i v e r s for the m e a s u r e m e n t of a t t enua- t ion above 300MHz. Acust ica, 18, No. 2, p. 105 (1967).

To o v e r c o m e the dif f icul t ies of m e a s u r e m e n t s of high f r e - quency ul t rasound, t e m p e r a t u r e r e s i s t i v e e l emen t s were in- ves t iga ted . These a r e the rmocoup le e lements , the min i a tu r e NTC r e s i s t o r s and thin (BaSr)TiO 3 d i s c s as P T C - r e s i s t o r s . These devices r e g i s t e r the total energy d i ss ipa t ion and a r e not dependent on the pa ra l l e l i sm , the su r f ace f in ish or the homogenei ty of the t r a n s d u c e r s and can be used in the giga- he r t z f requency range. Resul t s of some com para t i ve expe r i - men t s at approximate ly 312MHz in the 21°-42°C t e m p e r a t u r e r ange a r e given. (6 f igures , 1 table, 8 r e f e r e n c e s ) (Ul t ra - sonics 1967, a b s t r a c t 655)

194 ULTRASONICS July 1967

LOVELACE, J. F. Mathemat ica l a n a l y s i s of the ef fec ts of d i a m e t e r and wal l th ickness on u l trasonic inspect ion of pipe but t welds. M a t e r i a l s Evaluat ion.

Resu l t s of an inves t iga t ion conducted to d e t e r m i n e the f e a s i - bi l i ty of u l t r a son ic detec t ion of in t e rna l defec ts in pipe butt welds a r e r epor t ed . The s i ze s and m a t e r i a l s of i n t e r e s t were those used for c r i t i ca l c i r cu i t s in the cons t ruc t ion of sub- m a r i n e s . A sens i t iv i ty s t anda rd was developed which u se s a c a l i b r a t e d a t tenua tor . It is thought tha t the r e l i ab i l i ty of u l t r a son ic t es t ing i s comparab l e to rad iography. Some a n o m a - lous r e f l ec t ions f rom d iscont inu i t i es in pipes below 0 .5 in (1 .27cm) wall th ickness have been o b s e r v e d and a r e ana lyzed theore t i ca l ly . (8 f igures , 1 table, 6 r e f e r e n c e s ) (Ul t rason ics 1967, a b s t r a c t 660)