RESEARCH
reaching a velocity of 50 t o 60 feet per second before it begins to slow down a s maximum compression is a p proached. T h e important part of t h e compression-decompression cycle takes about O.002 second. A compression ratio (the significant factor) of 100,000 to 1 can b e achieved this way, a n d pressure beneath the piston can reach 100,000 pounds p e r square inch, o r more. While Sage doesn't think specific temperature figures have real meaning here, t h e maximum energy level beneath t h e piston is equivalent to an apparent tem-
perature of 10,000° F . ( T h e device could handle a driving air pressure of u p to 5000 pounds per square inch, but t o date Sage has found no reason for going that high.) To be suitable for study, a gaseous system must react, during the relativelyshort period of high temperature and pressure, at a high enough rate so that it both approaches, equilibrium and shows measurable changes in composition after reaction. T h e carbon-oxygen system so qualifies and was used, says Sage, to evaluate the ballistic piston's performance.
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• Easy Analysis.. Analysis is actually quite convenient. When the piston h a s rebounded to an intermediate position the sample is withdrawn in a vacuum bulb and analyzed. O n t h e negative side, kinetic events beneath the piston must be determined b y interpolating backward, mathematically, from t h e measurable data. Also, Sage doesn't claim that ther mo dynamic equilibrium is achieved in the apparatus, although it does allow study u n d e r conditions difficult, if not impossible, t o create i n a steady state experiment. So far, Sage and Longwell have worked most thoroughly on the piston's time-position history, Using electrical contacts and timerrs, they can fix piston position to within 0.OO1 inch and 1 microsecond, which h a s proved satisfactory for the pur-pose. They are n o w at work on the system's time-pressure history, using piezoelectric measurement. Here, it appears among other things that lower driving air pressure leaves t h e reactants a t high compression longer but achieves lower peak pressure. Energy transport within the system will be studied next, according t o Sage, who says cooling rates as high a s 4° F . per microsecond have already been measured. -Cooling rate appears to vary roughly a:md inversely with t h e square root of the piston weight, changes of which can thus be used to» vary the time-terraperature relationship in the system over a reasonable rangeAlso, the fugacity—temperature relationship in the system c a n b e c h a n g e d within limits fc>y adding varying amounts of helium, which shows relatively rapid, isotropic changes of t e m perature with pre-ssure.
Free Radical Future Recent studies in f r e e r a d i cal chemistry via i r r a d i a t i o n may give* dues t o reaction processes JLVADIATIONT EFFECTS are now of g r e a t
interest in the atomic energy programs for preserving foods, therapy, and p r o moting chemical, reactions. I n e a c h case, the radiation produces reactions, b u t exactly how is the question. T h e picture remains very incomplete, b u t a study of the free radicals resulting from irradiation is providing some clues. At the Oak R£dge National L a b o r a tories, Ralph Livingston, Henry Zeldes, and Ellison Taylor irradiated various acids—sulfuric, phosphoric, and p e r chloric—with gamma particles. At liquid nitrogen temperatures, these i r -
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radiated acids were found to give off atomic hydrogen as free radicals. Microwave absorption techniques make observation of atomic hydrogen's presence relatively easy. T h e ORNTL group finds that a s t h e acids are warmed, t h e microwave absorption dis appears as t h e atomic hydrogen enters chemical reactions a n d vanishes. A study of t h e speed with which atomic hydrogen enters reactions at different temperatures gives some clues to the nature of t h e s e reactions. Atomic hydrogen is also seen on ir radiated, high-surface-area glasses as a
product from absorbed water. This suggests t h e use of the method t o study the nature of atomic hydrogen o n cata lytic surfaces. F u r t h e r research is needed to see if t h e technique can be applied, Livingston said at the Atlanta meeting of the American Association foi the Advancement of Science. Free radicals m a y b e studied b y a number of methods. F o r example, those p r o d u c e d in flames and electiic discharges through gases can often be studied b y a spectroscopic analysis of the light given off. T h e paramagnetic technique is particularly useful for irra-
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diated materials since high concentra tions of free radicals can often be easily prepared a n d stabilized b y -working a t very low temperatures, says Livingston. Because free radicals h a v e a t least one unpaired electron they show a magnetic behavior. In using t h e paramagnetic resonance technique, materials contain ing free radicals a r e placed i n t h e field of a large magnet. T h e i r magnetic property causes the free radicals t o line u p in the field. Microwave absorption by t h e radicals occurs t h r o u g h a mech anism involving a reorientation of trie unpaired electrons i n t h e free radicals. W h e n the free radical e n t e r s chemical reaction a n d a paired electron bond is formed, t h e radical loses i t s magnetic behavior a n d microwave absorptions end. Much additional work is needed t o u n d e r s t a n d more fully t h e nature of free radicals involved in various radia tion processes, Livingston declares. Especially needed for industrial appli cations is more research t o develop fur ther m e t h o d s for studying atomic h y drogen's activity on catalytic surfaces. But low t e m p e r a t u r e free radical stud ies have already been valuable i n help ing t o answer some questions involved with the n a t u r e of radiation damage r e actions, h e concludes.
Kellogg Research Center Spencer Kellogg & Sons recently o p e n e d a n e w research center at Buffalo. T h e center consists of t w o units—a research office a n d laboratory building a n d a separate pilot plant— and covers 20,000 square feet of floor s p a c e . T h e cost of t h e present build ings and l a n d is about $450,000; equip ping the pilot plant will take about another $100,000. Present staff is 3 5 ; a staff of 70 is planned. T h e l a b building is e q u i p p e d for re search in t h e fields in w h i c h Spencer is active: vegetable oils i n industrial a n d protective coatings applications, edible oils a n d fats, a n d p r o d u c t s derived from vegetable proteins. T h e project also includes facilities for basic and analyti cal research, technical service, a n d supervision of p l a n t quality control.
V Cells of Erlichs' a s c i t e s m o u s e t u m o r can b e quick frozen b y a method d e vised in t h e physiological chemistry d e p a r t m e n t of UCLA's medical school. T h e frozen cells r e m a i n capable of in fecting mice for several weeks; w i t h refinement in techniques t h e cells m a y b e stored for u p to two years, according to R a l p h McKee a n d Barbara M c C a r t y .
