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Automotive Antifreezes

Description: From abstract: "A report on when antifreeze should be installed, what strength should be used, and what kind of antifreeze is best suited to the service involved."
Date: November 10, 1948
Creator: Brooks, Donald B.
Partner: UNT Libraries Government Documents Department

Berkeley Proton Linear Accelerator

Description: Construction of a linear accelerator which increases the energy of protons from a 4 Mev Van de Graaff injector to a final energy of 31.5 Mev.
Date: November 30, 1948
Creator: Alvarez, Luis W.
Partner: UNT Libraries Government Documents Department

The Radioactivity of Potassium 40: A Survey of Investigations

Description: From note: "Report discussing the history of the research of potassium 40 and its radioactivity, as well as the author's own investigations into the isotope."
Date: November 29, 1948
Creator: Weaver, B. S.
Partner: UNT Libraries Government Documents Department

The changes in the blood of humans chronically exposed to low level gamma radiation

Description: Ten individuals received an average of 0.211 roentgens of gamma radiation per week for a 77 period week (December 1946-June 1948) for a total average dose of 16.21 roentgens. During this period these 10 men carried out an experiment involving materials which emit gamma radiation and were monitored by daily film badges. The radiation delivered during a week was received in a five day work week and usually they received approximately one-half of their weekly dosage during one of the five days. A significant fall in total white blood count and absolute neutrophil and lymphocytes count was observed during the 77 week period. The degree of fall in counts would not have been predicted from experimental irradiation in animals and so other unknown factors may have been causal agents. It is suggested that hematological and exposure data from other laboratories be analyzed statistically to confirm or disprove the effect of such low- dosages of ionizing radiation on humans.
Date: December 31, 1948
Creator: Knowlton, N.P. Jr.
Partner: UNT Libraries Government Documents Department

Investigation of the Design and Control of Asphalt Paving Mixtures: Volume 3

Description: "This appendix presents a description of the loading equipment, the tracking procedure, and the results of tests and observations made during and after the traffic tests on the asphalt stability test section. Analyses of the test results are also included" (p. 1).
Date: May 1948
Creator: Waterways Experiment Station (U.S.)
Partner: UNT Libraries Government Documents Department

Investigation of the Design and Control of Asphalt Paving Mixtures: Volume 1

Description: "This report presents the results of laboratory and field tests conducted by the Corps of Engineers to develop a method for the design and construction control of asphalt paving mixtures. The investigation consisted of: (a) the selection of a test apparatus and the performance of laboratory studies to develop techniques and procedures; (b) the construction of a test section and the performance of traffic tests with 15,000 and 37,000-lb single and 60,000-lb dual wheel loads to obtain design criteria; and (c) additional laboratory work to adjust the test procedures to the design criteria" (p. 1).
Date: May 1948
Creator: Waterways Experiment Station (U.S.)
Partner: UNT Libraries Government Documents Department

Charts of Compressibility Factors and Charts Showing Quantities Delivered by Commercial Cylinders for Hydrogen, Nitrogen, and Oxygen

Description: Two charts are given for each of the gases hydrogen, nitrogen, and oxygen. The first gives directly the number of standard cubic feet of the gas which a cylinder will deliver. The second chart gives values of the compressibility factor and of the density.
Date: November 17, 1948
Creator: Hoge, Harold J.
Partner: UNT Libraries Government Documents Department

The excretion of hexavalent uranium following intravenous administration. II, Studies on human subjects

Description: Tracer studies employing uranium enriched in the isotopes U{sup 234}, U{sup 235} have been carried out in six human subjects; four males and two females. The uranium, 6 micrograms to 70 micrograms per kilogram of body weight was given intravenously in the hexavalent state as uranyl nitrate. Each individual of the series received a single injection of the metal except for one who was given two widely spaced doses. The first of these was when his condition was normal and the second after an acidosis had been produced by ingestion of ammonium chloride. Renal function tests including urinary catalase, protein, amino N to Creatinine N ratio and clearances of mannitol and p-aminohippurate were done before and after administration of uranium. Only at the 70 microgram per kilogram level in Subject 6 was there a slight rise in urinary catalase and protein suggesting that tolerance had been reached. The excretion of uranium was mainly in the urine, where from 70 to 85% of the administered dose appeared in the first twenty-four hours. Urine of the second twenty-four hours contained about 4% and the third twenty-four hour urine, 1.5% of the administered dose. Detectable amounts were excreted for at least two weeks.
Date: June 25, 1948
Creator: Bassett, S.H.; Frankel, A.; Cedars, N.; VanAlstine, H.; Waterhouse, C. & Cusson, K.
Partner: UNT Libraries Government Documents Department

Present status of polonium tolerance estimations

Description: This report contains a summary of biological information on distribution, excretion, and toxicity of polonium; a comparison of results obtained when maximum permissible exposure rates for man are calculated from available data by different methods; and a critical evaluation of the present status of Po tolerance estimates. A maximum permissible body content of the order of 0.2 {mu}c/70 Kg man is obtained by two methods. Applying an urinary excretion rate of 0.1% of body content/day, effective half-life of 34 days, and certain corrections for the non-exponential nature of Pb excretion, maximum permissible air and water concentrations and urinary excretion rates have been computed. Extrapolation from present data to calculations of tolerance levels in man is still difficult, and there appears to be no substitute for actual long term experiments. On the other hand, permissible exposure levels quoted herein appear to be, to a large extent, consistent with conservative practice.
Date: October 14, 1948
Creator: Hursh, J.B. & Stannard, J.N.
Partner: UNT Libraries Government Documents Department

The Preparation of Uranium

Description: The method used for the preparation of uranium metal in a fused state was reduction of uranium chloride with calcium in a refractory-lined bomb. The reaction was started by externally heating the bomb with a gas flame. The metal was obtained in a solid chunk which was covered with a layer of fused calcium chloride. The metal obtained by this process had a density of 17.6 which on remelting in a vacuum induction furnace rose to 18.8. The melting temperature of the metal was estimated to be no greater than 1400 C. The metal was malleable, and had a silvery surface when freshly cut which rapidly tarnished, becoming black in the course of a few days.
Date: August 26, 1948
Creator: Rodden, Clement J.
Partner: UNT Libraries Government Documents Department

Experiments of the Effect of Atomic Electrons on the DecayConstant of Be7

Description: In an attempt to detect a possible influence of the atomic electrons on the radioactive decay constant of Be{sup 7} they have measured {lambda}{sub Be}-{lambda}{sub BeO} and found (-3.0 {+-} 1.8) 10{sup -4} {lambda}{sub Be}. They describe also a method to measure mean lives of radioactive substances in a time short compared with the mean life.
Date: July 1, 1948
Creator: Segre, Emilio & Wiegand, Clyde
Partner: UNT Libraries Government Documents Department

Electronic Structure of the Heaviest Elements

Description: All of the available evidence leads to the view that the 5f electron shell is being filled in the heaviest elements giving rise to a transition series which begins with actinium in the same sense that the rare earth or 'lanthanide' series begins with lanthanum. Such an 'actinide' series is suggested on the basis of evidence in the following lines: (1) chemical properties, (2) absorption spectra in aqueous solution and crystals, (3) crystallographic structure data, (4) magnetic susceptibility data and (5) spectroscopic data. The salient point is that the characteristic oxidation state (i.e., the oxidation state exhibited by the member containing seven 5f and presumably also by the member containing fourteen 5f electrons, curium and element 103) is the III state, and the group is placed in the periodic table on this basis. The data also make it possible to give a suggested table of electronic configurations of the ground state of the gaseous atom for each of the elements from actinium to curium inclusive.
Date: July 14, 1948
Creator: Seaborg, G.T.
Partner: UNT Libraries Government Documents Department

Some Excitation Functions of Bismuth

Description: Excitation functions have been measured, using a 38-Mev alpha-beam and a 19-Mev deuteron beam for the following reactions: Bi({alpha},2n)At{sup 211}, Bi({alpha},3n)At{sup 210}, Bi(d,p)Ra E, Bi(d,n)Po{sup 210}, and Bi(d,3n)Po{sup 209}. The results are summarized in Figs. 4 and 5 and Tables I and II. A new isotope of astatine, At{sup 210}, has been identified; this isotope has a half life of 8.3 hr., decaying by K-capture to Po{sup 210} with the emission of a 1.0-Mev gamma-ray and a few conversion electrons.
Date: October 10, 1948
Creator: Kelly, E.L. & Segre, E.
Partner: UNT Libraries Government Documents Department

The Ion-Exchange Separation of Zirconium and Hafnium

Description: In the course of a rather cursory examination of the elution of tetra-positive ions from the cation exchange resin Dowex 50 with hydrochloric acid solutions, the authors have discovered a very effective method of separating zirconium from hafnimu. In view of the great labor involved in preparing even reasonably pure hafnium compounds by existing methods, they feel that this procedure will prove very valuable to those interested in obtaining hafnium compounds free of zirconium. Although the conditions which give satisfactory separation were first worked out using microgram amounts of material and the radioactive tracer technique, the run described here, involving milligrams of material, illustrates the applicability of the method to the production of significant amounts of pure hafnium and zirconium.
Date: October 11, 1948
Creator: Street, Kenneth, Jr. & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

An Isotope Effect in a Simple Chemical Reaction

Description: It has been found that the carbon dioxide obtained from the decarboxylation of singly-carboxyl labeled malonic acid is impoverished in the C{sup 14} label and that the acetic acid formed is correspondingly enriched.
Date: July 13, 1948
Creator: Yankwich, Peter E. & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

An Isotope Effect in Photosynthesis

Description: In the course of some kinetic studies on photosynthesis of barley seedlings, it has been found that plants utilize C{sup 12}O{sub 2} faster than C{sup 14}O{sub 2}. The plants were placed in a closed system containing an infra-red absorption-cell for the analysis of total CO{sub 2} and an ionization chamber for the determination of C{sup 14}O{sub 2} in the gas phase, both instruments recording continuously. Carbon dioxide, containing about 2% C{sup 14}O{sub 2}, was introduced in the dark and the specific activity at this point taken as unity. After a short dark period, the lights were turned on and photosynthesis was allowed to take place. A figure shows the result of a typical experiment. During the initial dark period the specific activity fell because of dilution by inactive respired CO{sub 2}. However, as photosynthesis proceeded, the specific activity of the residual CO{sub 2} rose until, when only 1/6 of it remained, the specific activity reached a peak some 20% higher than it had been at the start of photosynthesis. At this point the steady respiratory dilution became an appreciable fraction of the total remaining CO{sub 2}, and the specific activity dropped rapidly.
Date: November 23, 1948
Creator: Weigl, J.W. & Calvin, M.
Partner: UNT Libraries Government Documents Department

Paramagnetic Suseptibilities and Electronic Structure of AqueousCations of Elements 92 to 95

Description: Magnetic susceptibilities per gram atomic weight of elements 92 to 95 in most of their oxidation states were measured on 0.1 ml of solution which was 0.007 to 0.09 M in heavy element. The values obtained (all paramagnetic) in c.g.s. units x 10{sup 6} were: U(IV), 3690; Np(VI), 2060; Np(V), 4120; Np(IV), 4000; Pu(IV), 1610; Pu(III), 370; Am(III), 720. The results could be interpreted only on the basis of electronic configurations 5f{sup n}, even though susceptibilities were generally lower than the theoretical values and lower than experimental values for corresponding lanthanide cations. The lower values should be expected as a result of the Stark effect produced by fields of anions and of water dipoles. Failure of the Russell-Saunders approximation to the coupling between electrons may account for some of the error in the theoretical calculations. Wider multiplet splitting in the actinides accounts for the fact that the susceptibilities of Pu(III) and Am(III) are many-fold lower than those of Sm(III) and Eu (III) respectively.
Date: November 12, 1948
Creator: Howland, Jerome J. & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

The Path of Carbon in Photosynthesis

Description: The dark fixation of carbon dioxide by green algae has been investigated and found to be closely related to photosynthesis fixation. By illumination in the absence of carbon dioxide followed by treatment with radioactive carbon dioxide in the dark, the amount fixed has been increased ten to twenty fold. This rate of maximum fixation approaches photosynthesis maximum rates. The majority of the radioactive products formed under these conditions have been identified and isolated and the distribution of labeled carbon determined. From these results a tentative scheme for the mechanism of photosynthesis is set forth.
Date: March 8, 1948
Creator: Calvin, M. & Benson, A.A.
Partner: UNT Libraries Government Documents Department