Products • Q
Photosensitive
and Glass Developed
A glass which through prescribed use of ultraviolet light and heat can receive permanent colored photographic prints with three-dimensional effect, has been announced by Corning Glass Works, Corning, N. Y . One of the o u t s t a n d i n g characteristics of photosensitive glass from a practical standpoint is t h e ageless quality of i t s photographic reproductions which will not fade a n d are safe from any d a m a g e except s h a t t e r i n g the glass. This durability results from the fact t h a t the print is inside t h e glass and often permeates the whole piece. T o reproduce a picture, a negative is placed on t h e glass—originally crystal clear—and momentarily exposed to ultraviolet light from any of several sources, including sunlight, sunlamp, or arc light. Following removal of t h e negative, t h e photograph is developed by raising t h e temperature of the glass t o 1,000° F . T h e secret of this unique new photographic medium lies in t h e mixing of invisible submicroscopic metallic particles in t h e glass. T h e ultraviolet light precipitates these particles, making t h e m come out of solution and assume color. T h e possible color combinations are contingent on the t y p e of ingredients in the glass, and the shade or d e p t h of t h e color is determined b y the length of exposure. One glass will reproduce in brilliant red. Another permits pictures in blue, purple, r u b y , or orange, while a third prints in yellow and brown. T h e shade of color is determined b y length of exposure. W i t h one glass, exposure for a couple of minutes will make the entire picture purple. T o m a k e p a r t s of it red, the exposure is continued longer, with the other portions of the negative being masked off. T h e three-dimensional effect achieved is due to t h e fact that shadowed areas penet r a t e farther into t h e glass t h a n highlight areas. U n u s u a l lighting effects can also be obtained by placing a light behind t h e glass. Sensitive only to ultraviolet light, the glass does not have t o be handled with the same care required by photographic p a per. I n printing, black tape is used to m a s k off sections of the glass not covered by the negative, a n d t h e process can be carried o u t in room light. T h e uses of this m e d i u m potentially are m a n y according to Corning. Physically it m a y b e tailor-made for almost any p u r pose a n d tempered t o the desired strength. Reproduction of extremely fine detail is possibly due t o the lack of " g r a i n " in t h e
1822
Processes
$=
by
Corning
design—due in turn to the smallness of t h e particles making u p t h e picture ( t h e y are smaller t h a n t h e silver grains in p h o t o graphic emulsions). Corning h a s also developed photosensitive opal glasses, whose m y r i a d microscopic t r a n s p a r e n t particles scatter light in different directions. Colors possible in this m e d i u m are white, red, blue, yellow, or brown, and combinations of those colors. T h e opal and t r a n s p a r e n t glasses can be combined to m a k e designs side b y side or superimposed so t h a t t h e opalescent glass forms a background for a t r a n s p a r e n t colored surface image. Following are some specific uses for p h o tosensitive glass: p o r t r a i t photographs, scenic photographs, d e c o r a t e d glassware (tableware, goblets, vases), costume jewelry (miniature portraits, signet rings, religious emblems), church windows, p h o t o murals, decorative tile, illuminated a d v e r tising displays, p e r m a n e n t records in m i crofile print, i n s t r u m e n t dials, a n d l a n t e r n slides.
Allyl Sucrose
Varnish
A h e a t - a n d chemical-resistant varnishlike coating from allyl sucrose, said t o be unaffected by alcohol or b u r n i n g cigarets, has been a n n o u n c e d b y Sugar R e search F o u n d a t i o n , I n c . , 52 Wall St., N e w York 5, N . Y . I t w i t h s t a n d s t e m peratures u p to 400° so t h a t wood u n d e r t h e varnish will char before t h e coating is marred. Original work on t h e formula was carried on a t t h e E a s t e r n Regional Laboratory of t h e D e p a r t m e n t of Agriculture under the supervision of P . L . Nichols a n d Elias Y a n o v s k y . Allyl esters of c a r b o h y d r a t e s polymerize to form resins w i t h unusual toughness a n d other properties needed for coating c o m p o u n d s . F u r t h e r tests are being carried o u t t o see how economically t h e new c o m p o u n d can be m a d e . B o t h allyl chloride a n d sucrose, t h e main ingredients, are normally abundant.
Cosmic Produces
Radiation Carbon 14
T h e existence of carbon 14 in m e t h a n e derived from sewage h a s been cited as evidence of t h e p r o d u c t i o n of radioelem e n t s b y cosmic radiation according to a report in Science [ 105, 576 (1947)] by E . C . Anderson a n d W . F . L i b b y of t h e I n s t i t u t e of Nuclear Studies of t h e University of
CHEMICAL
Chicago, a n d S. Weinhouse, A. F. Reid, A. D . K i r s h e n b a u m , a n d A. V. Grosse of H o u d r y Process Corp. The existence of such elements h a d previously been predicted by D r . Grosse, a n d the formation of C 1 4 by the n e u t r o n s produced by cosmic radiation h a d been forecast b y Dr. Xdbby. T h e work of s e p a r a t i n g the various isotopes of carbon from the m e t h a n e was carried out at the H o u d r y plant near Marcus Hook, Pa., a n d t h e radiation m e a s u r e m e n t s were m a d e at the University of Chicago where it was found t h a t the radiation w a s identical with t h a t of Cu produced in the atomic pile. There; is believed to be sufficient C 1 4 formed b y cosmic radiation so t h a t all chemical forms in exchange equilibrium with atmospheric carbon dioxide (which includes all carbon in living m a t t e r ) will contain some of the radioactive form. M e t h a n e made from petroleum was found to contain none of the C 1 4 . T h i s was a t t r i b u t e d t o t h e fact t h a t t h e petroleum h a d long since lost its radioactive material since C 14 has a half-life of 5,000 y e a r s .
Coating for Irregular Surfaces A vinyl-type coating has recently been perfected b y Heil Process Equipment Corp., 12901 E l m w o o d Ave., Cleveland, Ohio, for t a n k s and rack fixtures u s e d in t h e plating a n d chemical industries. Heilex 445 (also available as a lining) is said to have well-defined resistance to chemicals and t o be n o t e d for its t o u g h surface a n d high bonding characteristics. Acids such as sulfuric, hydrofluoric, and hydrochloric, as wrell as nitric and chromic oxidizing acids, h a v e n o deteriorating effect. Physically, this plastic is r u b b e r y and tough, and resists abrasion and rough handling. Another p r o p e r t y of Heilex 445 is the negligible effect of temperatures u p to boiling. T h e coating has been approved b y manufacturers of nickel salts for bright nickel plating. It is giving good service on racks, stanchions, fixtures, ta.nks in copper, nickel, and chrome sequerLce. It protects t h e p l a t i n g solution from contamination a n d the rack from corrosion.
Quartz Produced
Crystals at NRL
Quartz crystals suitable for use i n electronic devices h a v e been successfully grown a t t h e N a v a l Research Laboratories in Washington, D. C. Crystals t h u s far produced a p p e a r to h a v e all t h e properties of n a t u r a l l y grown crystals, a n d the m e t h o d promises t o release this country from dependence on foreign sources for supply of this i m p o r t a n t material. T h e process is a n a d a p t a t i o n of a Germ a n technique which proved inherently unsuitable. I t consists of growing the crystal from a seed placed in a solution of
AND
ENGINEERING
MEWS
silica, water, a n d sodium hydroxide or sod i u m c a r b o n a t e a t t e m p e r a t u r e s of 350° to 4 0 0 ° C. a n d a t pressures of 2,000 t o 3,000 lb. per square inch, t h e v a p o r pressure of the s y s t e m . T h e entire process is carried o u t within a steel b o m b . P . H . Egli, director of the project, r e p o r t s t h a t before working o u t the final m e t h o d extensive studies were m a d e t o o b t a i n t h e necessary solubility d a t a . F r o m these i t developed t h a t within t h e o p t i m u m solubility range of silica two immiscible phases formed differing only in t h e i r w a t e r content. T h u s b y p l a n t i n g seed in t h e phase h a v i n g t h e higher silica c o n t e n t t h e efficiency of t h e m e t h o d was greatly enhanced. New e q u i p m e n t is now being installed t o m a k e possible t h e production of larger crystals.
Bleaching
microfilm, S I ; trations) .
3 5 pages including illus-
G e r m a n production of phthalic anhyd r i d e from n a p h t h a l e n e and its conversion to P a l a t i n o l plasticizers a r e described in r e p o r t P B 47,71S (microfilm, S I ; photos t a t , §2; 19 pages). A n oxidation vessel with a u t o m a t i c t e m p e r a t u r e control used in t h e process is of particular interest. T h e raw materials used b y I. G. Farbeni n d u s t r i e a t Ludwigshafen in t h e phthalic a n h y d r i d e process are pressed n a p h t h a lene, sulfuric acid, calcium carbonate, and a v a n a d i u m oxide catalyst. T h e catalyst is p r e p a r e d b y diluting potassium sulfate w i t h water a n d ammonia a n d by precipit a t i n g t h e silica with dilute sulfuric acid. Use of a m m o n i a is said t o reduce subseq u e n t filtration time. T h e n a p h t h a l e n e is vaporized in a steel t o w e r in w h i c h preheated a i r flows over the surface of t h e liquid. Emerging from the vaporizer a t 120° to 130° C , t h e n a p h t h a lene air m i x t u r e is filtered to remove tar before e n t e r i n g t h e oxidation vessel. T h e oxidation process is essentially a salt b a t h accomplished in a rust-free steel vessel containing c a t a l y s t tubes arr a n g e d a r o u n d tubular air condensers. An air j a c k e t surrounds the reaction vessel. Specially designed blades circulate the salt m i x t u r e from the catalyst zone to the inner
Clay
Adsorbed, an adsorption clay available in b o t h t h e n a t u r a l and a c t i v a t e d states, is being offered by Imiis, Speiden & Co., 117 L i b e r t y St., N e w Y o r k , N . Y . I t s chief use is in decolorizing vegetable, m a r i n e , n u t , and petroleum oils. I t also can be used to excellent a d v a n t a g e in t h e recovery of crankcase oils a n d d r y cleaning solvents.
air condenser zone. T h e h e a t capacity of t h e salt b a t h is such t h a t oxidation can be interrupted for as m u c h as five hours and resumed successfully w i t h o u t a n y external heating. T h e salt b a t h is m a i n t a i n e d at 330° C . for a new c a t a l y s t working a t 350° C . Both t e m p e r a t u r e s are increased for a catalyst more t h a n five years old. T h e t e m p e r a t u r e of t h e c a t a l y s t rises as n a p h thoquinone increases, m a k i n g possible a c c u r a t e heat control of the oxidation. C r u d e phthalic a n h y d r i d e from the oxidation vessel is condensed b y 15 sets of receivers which reduce t h e t e m p e r a t u r e a n d deliver t h e p r o d u c t t o t h e distillation system t h r o u g h screw conveyors a n d connecting pipes. Distillation takes place in t w o stills after the charge is refluxed t o a satisfactory color. Yield of p u r e phthalic a n h y d r i d e is 8 6 . 5 % of t h e theoretical. T h e Palatinol plasticizers m a d e by I . G. F a r b e n i n d u s t r i e were derived from p h t h a lic anhydride, esterification being based o n removal of the w a t e r formed during reaction. M e t h o d s employed varied for t h e particular alcohol being processed. F o r m e t h a n o l and e t h a n o l t h e w a t e r was absorbed b y sodium bisulfate, for butanols t h e water was removed as t h e binary with t h e alcohol, and for alcohols higher t h a n b u t a n o l the water was removed azeotropically with a n entrainer such as benzene or ethylene dichloride.
OTS Reports Copies of the following reports can be obtained at the prices indicated from the Office of Technical Services, Department of Commerce, Washington 25, D. C. Orders should be accompanied by check or money order, payable to the Treasurer of the United States.
"PRECISION"
Silicon carbide, or C a r b o r u n d u m , is a promising ceramic m a t e r i a l for use in the high t e m p e r a t u r e s a t which gas turbine blades must operate, according t o G e r m a n tests out lined.in report P B 47,012 (photos t a t , S2; microfilm, SI; a limited supply of mimeographed copies, 75 c e n t s ; 26 pages). N o t only were test pieces of silicon carbide strong a n d rigid far above 1,300° C , b u t t h e y also showed exceedingly high h e a t conductivity as compared with other m a t e r i a l s tested.
,,
Operated entirely by air, the "Precision" Aero-Shak is so well designed that it incorporates every desirable feature of the ideal mechanical shaker. Adjustable to all kinds and shapes of containers and flasks, explosion-proof and silent in operation, Aero-Shak simulates the motion of manual shaking yet because of its vertical construction, occupies a minimum of space. Write for detailed Bulletin 430-1.
F o r the convenience of businessmen and researchers, selective lists of technical reports a n d d o c u m e n t s a r e available in 13 specialized industrial fields. T h e lists include t h e following fields: plastics, ceramics, adhesives, paper, deterioration, iron ores, a n d forestry a n d wood products. T h e lists contain only t h e most important materials available from O T S in each of the selected fields. P u r e d e g a s s e d iron can effectively replace m o l y b d e n u m and nickel in the construction of electrodes, getters, a n d other metallic p a r t s of electron t u b e s , according t o a J a p a n e s e research d o c u m e n t included in report P B 49,839 (photostat, S3; V O L U M E
2 5,
NO.
25
*
»
Preeision n Aero-Shak
"Precision" A e r o - M i x Wherever explosive vapors or infiamAERO-M1X mable liquids are present, absolute safety is guaranteed for the stirring operation by Aero-Mix, the efficient variable speed stirrer driven by compressed air. Operates on air pressures as low as 2 lbs. Available in three sizes. Speeds of 2500 R.P.M. attained ac 10 lbs., 7500 R.P.M. ac 65 lbs., on senior model. Write for detailed Bulletin T10304-I.
See
Your
Laboratory
Supply
Dealer
Precision Scientific Company y iC.JHtl
»
JUNE
2 3,
1947
A..G O . -»j7., • I t 1 - .
1823
