I&EC TRENDS
TODAY
Long-term storage of nuclear wastes is promised by a continuous, phosphateglass solidzjcation process based on earlier work by G. Barton of G.E.'s Hanford installation. Conducted by remote control, the process starts with the addition of phosphoric acid to concentrated nuclear waste. The waste is further concentrated by evaporation of nitric acid and water and then fed into a platinum-lined melter operating at a temperature of 1250" C. Further heating reduces the volume and converts the residue into a molten glass mix which overflows into a storage vessel. These tests are designed to determine whether or not all thejssion products can be trapped in the glass and can be expected to provide samples of fully radioactive glass for observation and evaluation.
A new vacuum deposition technique produces cadmium suljide transducers that generate either transverse or longitudinal waves. The method, developed by N . F. Foster of Bell Telephone Laboratories, uses a heated boat from which the cadmium suljide is evaporated and deposited on a metal-plated surface. Transducers that generate predominantly transverse waves are formed when the sulfide vapors strike the metal surface at oblique angles. Transducers are formed that generate longitudinal waves when the vapors strike the surface at right angles. Transducers formed by this process have no need for acoustic jilters formerly used to suppress unwanted modes. These units, recommended for memory elements in computers and high-frequency delay lines, range in frequency from 100 mc. to 1800 mc. Thickness is controlled by regulating the evaporation time.
DIREC,IoR
6oR
* n o u or
CAOMIUM S U L P H ~ O E
A more systematic method of predicting the reactions of irradiated chemicals is expected to result from studies conducted by H. E. Zimmerman of the University of Wisconsin's Chemistry Department. Preliminary studies with 4,4-diphenylcyclohexadienone indicated that normal treatment with acids or heat produced 3,4-diphenylphenol; irradiation of the parent compound before treatment, resulted in the predicted 2,3-diphenylphenol. Further investigations are expected to relate the structure of these irradiated, high energy molecules to a set of rules governing their behavior. Methods for calculating the heating effects produced when a pulsed ruby laser beam strikes metallic objects have evolved from studies carried out at the Honeywell Research Center. These methods can be expected to further the study of the laser's value as a plasma source and as a high density electron source. Some of thejindings, as described by J . F. Ready of the Center, are as follows: heating effects, resulting from the absorption of the pulsed laser radiation at powers below those producing vaporization, have been calculated theoretically for iron, aluminum, tungsten, and other metals; measurements performed on electrons emitted from the surface heated by the beam at relatively low powers, indicate that emission is thermal in origin. Theoretical predictions were verified by the experimental results. Studies of surface damage caused by power levels strong enough to vaporize the absorbing material, resulted in models which could predict the depth of the material vaporized. VOL. 5 7
NO. 1
JANUARY 1965
7
HOW TO CONTROL FORMULATIONS, PRODUCTION, AND COSTS POLYVINYL ALCOHOL,
Vary the surface tension of water or interfacial tension between oil and water.
Fine control of polymerization degree helps meet exact requirements.
With Gelvatol, a large family of polyvinyl alcohol resins, you can now more accurately control formulations, production and costs. V i s c o s i t y ? Y o u c a n v a r y it smoothly with the specificationspanning range of Gelvatol (initial viscosities, 1.3 to 65 cps.) Mechanical properties? pH? Solubility? Surface and interfacial (water/oil) tension? Adhesive characteristics? Oil and solvent resistance? Films? Chemical derivatives? polymerization? Yes, you control them all better, because the polymerization of Gelvatol itself is better controlled. Shawinigan offers unusually fine variations in viscosity, ‘/. hydrolysis and residual polyvinyl acetate c o n t e n t i n t h i s , t h e world’s broadest polyvinyl alcohol line. Equally helpful is the technology that comes packaged with Gelvatol, Shawinigan’s quarter century of experience. In adhesives - Gelvatol builds viscosity, bond strength, water resistance. In paper coatings - it upgrades Mullen, wet strength, pick and grease resistance, fold endurance, other qualities. In textile finishes - it builds permanent stiffness, resilience. I n building products -it’s a binder. Gelvatol is also an effective emulsifying agent - is used in photosensitive coatings, films and molded products. If you have a new product gleam in your eye - see if Gelvatol won’t make it pay off faster . . . easier ! Write for our newest GELVATOL Brochure. SHAWl Nl G A N RES1 NS CORP. Dept. 3, Springfield, Massachusetts 01101
Improves the Mullen and 10 other qualities of paper and paperboard.
Dissolves rapidly and efficiently into clear polyvinyl alcohol solutions.
Ask about: GELVAB polyvinyl acetate; BUTVARB polyvinyl butyral; FORMVARB polyvinyl formal. Circle N o . BO on Readers’ Service Card
8
INDUSTRIAL A N D ENGINEERING C H E M I S T R Y
SHA WINIGAN RESINS CORPm
I&EC T R E N D S
INDICATORS FOR TOMORROW A n all-adsorption pump for producing hard vacuums (less lhan
torr) has been successfully tested by Linde. The unique feature of the pump is a cryosorption panel composed of a layer of Linde 73X molecular sieve bonded to an aluminum substrate. By cooling the reverse side of the panel to the normal boiling point of helium (4.2" K.) one can remove most of the helium naturally present in air (about 5p.p.m.), something that has been nearly impossible with cryogenic cooling alone. Bonded sieves represent a new potential for designers o f adsorption and catalytic equipment since they largely overcome heat transfer rate limitations associated with the low thermal conductivity of the sieves. Reverse osmosis promises significant quantities of potable water from sea water, brackish water, or sewage. The process, using thin sheets of semipermeable cellulose
acetate, is producing more pure water than the 7000 gallons a day originally planned f o r a desalination plant at Newport Beach, Calif. According to Dr. B. Keilin, of Aerojet's Von Karman Center, ejluent from the municipal sewage treatment plant in Azusa, Calif., was processed by this method. The waste water was converted to a product with a mineral and organic material level below that considered harmful. Detergent levels were reduced below the foaming level. More durable asphalt, designed to withsiand detrimental ejects of
atmospheric ozone and induced photo-oxidation efects, can be produced by replacing process air with oxygen or ozone itself in the asphaltjux. P. G. Campbell and J.R. Wright of NBS Institute for Applied Technology used an experimental apparatus, operating at temperatures lower than those employed commercially to produce coating grade asphalts. Light oils, normally lost during conventional asphalt production runs, are retained at these temperatures thereby reducing air pollution. Reduced manufacturing costs can be expected because of lower operating temperatures and shorter reaction periods. A better understanding of adhesion of plastics has been obtained from work conducted at the NBS Institute f o r Materials. The fundamental study is jointly sponsored by the Ofice of Army Research and the Bureau of Naval Weapons. Resolved in this study were the problems concerning the shape of the polymer molecule attached to a surface and the number of contacts made by the molecule with a surface. Ellipsometric measurements coupled with studies of the changes in polarized light brought about by adsorbedjlms showed that, at maximum adsorption from ideal solutions, the conformation of the polymer molecule was similar to that of a random coil. The thickness of adsorbed glass $finishes, vinyl tris (2-methoxyethoxy) silane and aminopropyltriethoxy silane, on glass prisms were also measured. The study showed that the organic portions of these finishes polymerized in solution or at the interface rather than individually adsorbing to the glass surface. From the results obtained with tritium-labeled styrene, anionically polymerized into molecular weights fractions of 38,000 and 76,000, the investigators observed that the rate of initial contact depends on dtjiusion of the polymer in solution. They also conclude that the number of contacts each chain makes with the surface (or degree of spreading) depends on the surface area available to it before it is blocked by a nei,qhboring molecule. VQL. 5 7
NO. 1
JANUARY 1965
9
