ing. It will b e n o t e d that a statistically significant correlation with job performance was obtained i n only one case, a n d this was not d u p l i c a t e d i n the following year. Better correlations were obtained with academic performance in the firstyear advanced course. In this course two separate guides a r e reported: first, t h e average grade on t h e 30 half-hour quizzes given weekly d u r i n g the class sessions; a n d second, t h e average grade o n the 30 weekly problems which a r e solved outside of class a n d involve about 15 hours of work each. As Table II indicates, a number of tests s h o w a significant correlation with the q u i z scores, but only the three sections of t h e Carnegie Foundation's experimental g r a d u a t e aptitude test showed a significant correlation with the problem scores. ( This test also showed t h e highest consistent correlations with job performance; correlation coefficients of its three parts were 0.27, 0.37, a n d 0.28 for a group of 27 men. ) Factors such as perseverance, interest, and thoroughness evidently are far more important in the successful solution of long problems than the purely mental factors which t h e tests attempt to measure. T h e experiments with testing thus have proved of value only in the educational classes. As yet t h e testing program has not shown much value in predicting over-
all ability o n the job. This is in contrast to the relatively high correlation found b e tween college standing and over-all job performance. Apparently college standing reflects not only purely mental ability b u t other traits as well. Besides t h e intelligence tests the Kuder preference record w a s given to both groups of men. This is a test which attempts to measure interest in nine types of activity: mechanical, computational, scientific, persuasive, artistic, literary, musical, social service, and clerical. The general profile of interests showed t h e pattern normal for technical men—high scientific and lowclerical and social service interests [Kuder, G. F., "Manual for the Kuder Preference Record ( R e v i s e d ) , " Chicago, Science R e search Associates, 1946; Speer, G. S., J. Psych., 25, 3 5 7 - 6 3 ( 1948)]. Men rated in the upper third on job performance tended to show a higher mechanical and a lower literary interest than men in the lower third. Other differences were minor or inconsistent in the two groups. Scores on t h e mechanical, computational, or scientific interest sections did not give significant correlations with either the quiz or problem grades in t h e first-year advanced course. Conclusions This study dealt only with recently graduated chemists and engineers selected
for an industrial training program tlirough normal employment procedure. The following conclusions are applicable to this limited group: 1. Performance on an industrial training program of t h e type described is a good measure of a young technical man's performance on a permanent job in his first years in industry. 2. College standing is definitely an important criterion of a young technical graduate's performance in industry. 3. No other quantitative or objective criteria of job success were found in the groups studied. 4. Although personality, working habits, and other personal traits are all important criteria for job success, initiative and aggressiveness a r e of outstanding importance. 5. A variety of intelligence tests w e r e of value in predicting standings in an educational program hut did not give good predictions of job performance. Acknowledgment The authors are indebted to Gilbert S. Bahn a n d John T. Russello for administration of t h e testing program. PRESENTED before the Division of Chemical Education at the 116th Meeting of the AMERICAN CHEMICAL SOCIETY, Atlantic Cit\, X. J., Sept. 22, 1949.
AEC Issues Seventh Semiannual Report A E C research p r o g r a m reflects definite trend tow a r d increased f u n d a m e n t a l a n d basic studies I T is no secret t h a t our great structure of nuclear technology is built on an extraordinarily slim foundation of basic knowledge about t h e atomic nucleus." In making this statement in a recent address, L e e A. DuBridge, president of the California Instituite of Technology and memb e r of the A t o m i c Energy Commission's General Advisory Committee, echoed a conviction expressed by many qualified scientists. M a n y of these scientists, including those in t h e A E C , are convinced that without an extensive program of basic scientific research, there will b e no foundation for fixture technological advances. Fortunately for science, recognition of the need of extensive basic research has not been limited to the scientists alone. Congress, in enacting t h e Atomic EnergyAct of 1946, specifically provided for basic research studies in addition to technical development. T h e act further required that the Government foster both public and p r i v a t e research i n the fields of nuclear processes; t h e theory and prod u c t i o n of atomic energy; utilization of fissionable a n d radioactive materials for medical, biological, health, or military purposes; utilization of these materials and VOLUME
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A quarter scale model of t h e Bevatron at the University of California. The units beside the m e n a r e vacuum p u m p s . W h e n the full size, B-evatron is complete it is expected to accelerate protons to within 1% of the speed of light processes entailed in their production for other purposes, including industrial uses; and t h e protection of health during research and production activities. In view of the general accord as to the need for research, it is not surprising that the A E C lias devoted much time, effort, personnel, and funds to this purpose. In its seventh semiannual report, recently presented to Congress, the A E C has outlined its research activities. E v e n without considering classified research, which is omitted from t h e current report, the extent of these activities is impressive. T h e progress of the nation's atomic energy physical research program is dependent o n the availability of talented,
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trained scientists, specialized equipment, and research laboratories. The importance of this research is evident w h e n it is realized that over 5 0 % of the entire personnel is engaged in direct research in t h e physical sciences, reactor development, and biological and medical sciences. The $81 million AEC research budget this year will engage t h e services of 5,400 scientists. Of this total, $31 million is allocated to research in the physical sciences, $33 million for reactor development, and $17 million for biological and medical sciences. In the physical research program, $23 million are being spent to support t h e work of 1,350 scientists in AEC installations, and $8 million 537
tor the οΌϋ scientists engaged in "off-site" contract work. In addition to t h e $ 3 1 million for op erating physical r e s e a r c h , $25 million are being spent on construction of new physi cal research facilities and equipment. Construction work in t h e reactor program will call for $41 million. AEC has eight major installations, owned o r leased b y the Government, and four other installations on university campuses, almost completely s u p p o r t e d by Government funds. In addition to con tracts for reactor development, about $4 million w e r e spent during 1949 on con tracts w i t h universities, research institutes, industrial organizations, and other gov ernment agencies. M u c h of t h i s work is basic research. T h i s portion of the A E C work is tied in w i t h a similar program maintained by the Office of Naval Hesearch. Atomic E n e r g y Research The general guides for atomic energy research are outlined in the Atomic En ergy Act of 1946, w h i c h directs the A E C to find o u t ( a ) h o w atomic nuclei are put together and what forces operate within them, so as to obtain a fuller u n d e r s t a n d ing of h o w atomic energy is released and how it c a n b e put t o work; a n d ( b ) how to work with and u s e fissionable materials, and all other materials which assist in the production of atomic energy and which are produced by atomic energy. The particles which issue from bom barded nuclei give an indication of the nuclear structure a n d t h e forces involved. Bombardment of nuclei is carried on with charged particles o r neutrons. The prin cipal work with particle accelerators is concentrated on t h e light nuclei such as hydrogen and its isotopes. In addition to h y d r o g e n studies, workhas been done on other light nuclei. For example, lithium 7 has b e e n obtained from the rare lithium 6 isotope b y deuteron bombardment, and beryllium 7 has been produced by a proton b o m b a r d m e n t of boron 1 0 . Studies on t h e excited state of oxygen 16 will be undertaken when nec essary instruments have been p r e p a r e d . A major a d v a n c e m e n t in t h e efforts of AEC scientists t o discover information about t h e b i n d i n g forces of the nuclei has resulted from t h e u s e of t h e 184-inch cyclotron at Berkeley a n d t h e linear ac celerator. A tentative report o n progress in the study of proton-proton reactions concludes that "it is apparent t h a t present theoretical concepts must be modified, and perhaps new concepts introduced, before a satisfactory mathematical description of the proton-proton force will b e at h a n d . " Symmetrical c l e a v a g e is most often found i n t h e fission p r o d u c t s obtained from high-energy, fast-particle bombard ment of heavier e l e m e n t s such as bismuth. These results are q u i t e different from the asymmetric p r o d u c t s resulting from the elow-neutron fission of u r a n i u m and plutonium. I n a d d i t i o n to fission, fast bombardment of a t o m i c nuclei with mil lion-electron volt particles chips off (spal 538
lation) pieces of all sizes. T h u s , from bombardment of uranium, nearly every known element m a y be found, as well as substances never before known. As a re sult, research of this n a t u r e can be ex pected to furnish theoretical physicists and mathematicians a wealth of data o n atomic structures. Scientists hope that through the use of high-energy particle accelera tors which resulted in production of the theoretically predicted meson, t h e y may obtain the answer to the question of what holds the nucleus together. Research with uncharged particles ( neu trons ) is another principal line of study being followed to solve t h e question of atomic structure. I n this case, o n e of the major problems is t o produce neutrons of various measured energies. Such control is difficult since t h e lack of an electrical charge renders electrical and magnetic field controls useless. T h e short half-life of 30 minutes or less further complicates the problem. In general, neutrons are produced by knocking t h e m out of nuclei by b o m b a r d m e n t or by means of nuclear fission in a reactor. Research in Chemistry A sizable portion of t h e problems of atomic energy development are chemical in nature. T h e s e range all the w a y from the extraction of radioisotopes for medical research to t h e designing of a reactor to drive a warship. In most studies of atomic nuclei, chemistry plays some part and in others it plays a major role. This is particularly true in t h e handling and processing of special materials t h a t result from nuclear reactions, or are essential to bring t h e m about. Most chemical research conducted by the A E C is d i r e c t e d t o w a r d solving prac tical problems. I n many cases this in volves development or a d a p t a t i o n of al ready understood principles of t h e be havior of atoms a n d molecules. I n other instances, however, the principles are so new that the work of the chemists is es sentially basic in t h a t it involves explora tions in u n k n o w n regions. O t h e r basicresearch is sponsored which has no im mediate practical application. Examples of this are studies on newly created ele ments a n d t h e utilization of n e w nuclear research techniques for discovering facts about nature. In m u c h of this w o r k close cooperation b e t w e e n physicists a n d chem ists is essential. Chemical Separation Much of t h e chemist's work in t h e field of atomic energy comes under t h e decep tively simple h e a d i n g "chemical separa tion." T h e separation or extraction of one material from another, or more often from a mixture of others, had to be resolved in order to make t h e bomb possible. Simi larly, future progress is d e p e n d e n t on more effective means of carrying out com plex separations. I n this work, t h e chem ists have studied all k n o w n m e t h o d s for separations, including selective solvent extraction, distillation, precipitation, ionexchange, a n d liquid-liquid extraction. C H E M I C A L
W i t h the exception of two series of elements, the chemical properties of ele ments are d e p e n d e n t to a great extent o n t h e number of electrons in t h e outer shell. In such cases there is a fairly s h a r p c h a n g e in chemical properties b e t w e e n elements. In the rare earth series ( c e rium, number 58, through lutecium, n u m ber 71 ) and in the radioactive series c o m prising actinium ( 8 9 ) , thorium (90), protactinium ( 9 1 ) , uranium ( 9 2 ) , n e p tunium ( 9 3 ) , plutonium ( 9 4 ) , americium ( 9 5 ) , curium ( 9 6 ) , and berkelium ( 9 7 ) , such sharp changes are not evident. I n these two areas successive elements a r e built u p , not by additions to the o u t e r shell, but by various additions a n d a d justments to t h e inner shells. It is in t h e s e t w o families of elements that separations in a p u r e form are difficult. T h e prime objective of t h e chemical research program is to gain a g r e a t e r understanding of t h e chemical character istics of the heavy element transition series. Knowledge gained about some of these elements has assisted in d e a l i n g with the chemistry of others in the s a m e series. Since available samples are often of the order of a few millionths of a gram, their chemical properties are most often studied by tracer m e t h o d s based o n their radioactivity. Preparation of p r o tactinium and americium in a metallic form in very minute a m o u n t s has b e e n accomplished. The separation of t h e s e elements from each other a n d from t h e rare earth fission p r o d u c t s has involved detailed studies of methods. T h e s e p a r a tion problem has b e e n q u i t e p r o n o u n c e d in the case of the newer m a n - m a d e ele ments, 95, 9 6 , and 97. T h e s e studies have resulted in marked advances in t h e t e c h n i q u e of ion-exchange. Another factor which complicates t h e work with these elements is the n e c e s sity for shielding to protect workers from t h e effects of radioactivity. A good ex a m p l e of this is observed in work w i t h americium. Chemists at Los Alamos suc c e e d e d in separating a small q u a n t i t y of this element ( atomic n u m b e r 9 5 ; atomic weight 2 4 1 ) for conversion t o curium by neutron b o m b a r d m e n t . It h a s an alpha activity three times greater t h a n r a d i u m a?ri··•·.·ugh its g a m m a radiation is not as penetrating. L e a d shielding a n d other precautions are required when w o r k ing on this element. T h e immediate practical value of t h e improved separation techniques is in solu tion of the very pressing problem of e x tracting plutonium from t h e u r a n i u m slugs used in the Hanford reactors. T h e information gained will also b e essential if greater efficiency is to b e achieved i n t h e production of fissionable materials from new reactors which are now in t h e planning stage. A E C chemists consider t h e p l u t o n i u m separation the most difficult p r o b l e m ever undertaken o n a large scale. Not only is the amount of t h e metal in the slugs very minute, but it is mixed with 40 o r more elements from w h i c h it m u s t b e separated. Typical problems which m u s t b e faced include die dissolving of p l u A N D
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toniurn, precipitation from dilute solution, extraction of plutonium and uranium compounds from aqueous solution by nonaqueous solvents, and the preparation of plutonium metal from its salts. Interference effects resulting from the presence of 40 to 50 other elements, especially the rare earths, "which are not commonly encountered in chemical separations, must also be determined and overcome. In an attempt to solve some of these problems, much research has been carried out on the chemistry of the 14 rare earth elements. Prior to 1940 little work had been done in this field due to the lack of practical value of the elements and the difficulties involved in separating them. As a result of much fundamental, experimental, and theoretical chemistry, A.EC chemists developed a refined ionexchange process to effect the separations. In this process, a solution containing rare earth elements is allowed to flow downward through a long thin vertical tube which is packed with resin. This solid resin removes the various elements from solution by the process of ion exchange. After the rare earths are absorbed on the resin, a weakly acid sodium citrate solution is poured through the column. Under the action of this solution, the grip of the resin upon the rare earths seems to be loosened, but to a slightly different degree for each rare earth element present. As the solution passes down the tube t h e rare earths begin to be carried with it, but at different rates, so that the solution as it emerges from the bottom of the column is found to carry one rare earth for a time, and then another for a time, then a third for a time, and so on. By collecting these fractions in different vessels, a separation of the component rare earth elements is effected. Even though the quantities involved in these separations are small, they are quite radioactive, being the products of a nuclear reactor. The chemist, who must be protected by several feet of concrete, views his materials with mirrors and periA* the Argonne National Laboratory a "cave" is used by radiochemists for protection against gamma radiation
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scopes and carries out his work by remote control. Use of the ion-exchange process was instrumental in discovering the rare earth promethium ( element 61 ) and also in producing the first appreciable quantities of technicium, (element 43). It is of interest to note that this ion-exchange reaction has now been applied to other fields where separations are difficult, such as the nucleic acids. Other Chemical Research As stated previously, the determination of how atoms interact to form molecules is an important objective. Because of the many shell electrons involved in the interactions of most atoms, absorption spectra are quite complex. The complexity often precludes the making of basic theoretical calculations based on studies of such spectra. For this reason, the relatively simple hydrogen molecule is the object of considerable spectroscopic study. Now that tritium (hydrogen 3) is available, comparison studies and interpretations may be made from studies of various combinations of hydrogen, deuterium, and radioactiye tritium. Recent attempts to photograph hydrogen spectra containing tritium have been quite successful. LEAD When people claim you'd get ahead Much faster if you had less lead, Before they venture further flattery Remind them of the storage battery. R.T.S. Certain aspects of work in atomic energy require a knowledge of the behavior of elements and materials under conditions of extreme cold approaching absolute zero and extreme heat of the magnitude found in the center of stars. Lack of such knowledge in the United States seriously handicapped the wartime program. One of the major problems in the high temperature work is to find refractory materials capable of withstanding the extremely corrosive effects of most molten metals. Research developed that certain cerium sulfides pnd sulfides of other metals had desirable properties in this respect. Progress has also been made in this field by combining predictions based on thermodynamic principles with known data as to the behavior of materials on the surface of the sun and stars and the study of geological processes which took place at elevated temperatures. Interesting experiments have been conducted on helium 3 and 4 at temperatures close to absolute zero. Results have shown that helium 4 becomes more sluggish as the temperature approaches absolute zero. However at a point a few degrees above zero, it abruptly changes to a so-called fourth state of matter and becomes a super heat conductor and super fluid. Helium 3 on the other hand shows no such characteristics within one degree of absolute zero. The preparation of isotopically pure He 8
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was effected by the neutron bombardment of lithium. When lithium captures a neutron it breaks down into a mixture of He4 and H 3 (tritium). The tritium is combined with oxygen to form a kind of water leaving the He* as a gas. The tritium emits a negative beta particle and becomes He 8 . Chemists have eliminated one of the dangers of working at low temperature by replacing hydrogen, which acts as a refrigerant in its liquid and solid states, with neon, which is inert. Metallurgy Success of the atomic energy program is dependent on metals and alloys which can perform adequately under the conditions of temperature, pressure, and radiation to which they are subjected. This is particularly true with respect to reactor development. Here again, although the goal is practical, much of the work must b e of a fundamental nature. The AEC program of basic research in metallurgy involves studies in several fields. I n regard to the strength of metals, considerable research is being conducted to determine the reasons for the extension or stretching of metals under stress at elevated temperatures ("creep"). Another research project has as its objective t h e determination of the reasons for the phenomena of the diffusion which occurs in solid metals a t elevated temperatures which however are below the melting point of the metal in question. Metallurgists are also applying thermodynamic principles to liquid metal solutions which have been used by chemists in chemical solutions. One of the mair> problems here is a practical one i.e. working at the high temperatures involved with molten metals. Studies to determine atomic structures of metals are being carried out particularly through the medium of X-ray research on lattice planes. In the field of corrosion, two main lines of investigation are being followed. The first, which is to solve specific problems. is the determination of corrosion effects on a given material under a given set of conditions. Experience has shown that the results obtained are generally not applicable to other situations. The second approach is a fundamental one calculated to reveal the basic nature and underlying cause of corrosion in metals. Due to the interest of the Office of Naval Research in this question, the AEC is limiting its work t o a few specific materials such as zinc and titanium. The effects of radiation on metals i^ another metallurgical problem. Hereagain the studies to determine the effects of radiation on hardness, electrical resistance, dimensions, strength, and othex properties are being changed over from a n empirical approach to a fundamental and basic study. Due to a similarity vn physical changes in metals from neutrc*xi bombardment a n d those produced b y mechanical effects, a study is being made t o establish the possible relationship b e tween the two phenomena. 539
