The idea of ''antiparticles'', as is well known, originated with Dirac, who in establishing the relativistic equations for the electron noted that besides the solutions corresponding to ordinary electrons there were also ''unwanted solutions'' corresponding to particles of electronic mass but of charge +e instead of the electronic charge - e. The discovery of the positron by CD Anderson offered a brilliant experimental confirmation of Dirac's prediction and gave the first example of an ''antiparticle.''

A general survey is presented of information in the uranium alloy field. Emphasis is centered on alpha uranium-rich alloys of special interest as uranium- base fuel element materials. The systems treated include uranium-molybdenum, uranium-silicon, uraniumzirconium, uranium-niobium, and uranium-zirconiumniobium (high uranium compositions). The uraniumfissium alloys are discussed in relation to their projected applications as fast reactor fuels. Equilibrium diagrams, transformation kinetics, and other pertinent data are presented for the uranium plus fissium'' element systems, e.g., uranium-ruthenium, uranium-rhodium, uraninum-palladium, and uraniummolybdenum-ruthenium. The properties covered include constitution phase diagrams, metallographic structure, physical and mechanicaly properties, transformation kinetics, crystallographic structure, thermal cycling, ad irradiation stability (where pertinent). Correlations between microstructure, heat treatment, and dimensional stability are emphasized, with particular reference to the U-2 wt.% Zr, U-5 wt.% Zr, and 1 1/2 wt.% Nb alloys. A discussion of the role of alloying and heattreatment in improving the dimensionaly stability and corrosion resistance of uraaium is presented, and an evaluation is made of the present status in attaining these objectives. (auth)

Data are presented on the absorption of molybdenum on activated carbon. The effect of retention time and linear flow on absorption, the use of sodium hydroxide as an eluant, and the possibility of recovering molybdenum from the caustic eluate are discussed. (auth)

Low-frequency abeorption centers, observed by electrical measurements in single crystals of rutile, can be produced by thermal quenching or optical irradiation in the edge of the eigen absorption region (600 A). They are observed when electric fields are applied parallel to the optic axis (crystallographic c axis) and are not visible with the field perpendicular to this axis. The temperature dependence of the principal dispersion indicates an activation energy of 0.18 ev. The centers can be explained by a localized electron transfer process along the optic axis. The introduction of silver and copper by thermal diffusion did not produce low frequency absorption spectra. (auth)

Note presenting wind-tunnel calibrations of three types of angle-of-attack sensing devices - the pivoted vane, the differential pressure tube, and the null-seeking pressure tube. Flight data on the position errors for three sensor locations - ahead of the fuselage nose, ahead of the wing tip, and on the forebody of the fuselage - are also presented. Various methods for calibrating angle-of-attack installations in flight are briefly described.

Memorandum presenting an analysis of a large number of liquid-metal-to-air heat-exchanger cores for the nuclear-powered liquid-metal turbojet cycle to determine which types yield the best overall net thrust per total engine weight. The performances of all exchangers considered were initially evaluated at a median condition. The performance of the best of each of the four types was compared with that of a shell-and-tube exchanger with the air flowing through the tubes, operating at the same condition.

The economic development of nuclear reactors depends upon the integrated progress in the fields of reactor design, fuel element design, reactor operation, and fuel production and separation. Broad criteria, which restrict the fuel element design, are determined by the mutual consideration of the problems encountered in all the above fields. Hence, no stage of reactor design or operation is independent of the fuel element problem, nor can the fuel element designer disregard the interest of any one field. As an introduction to the fuel element design problem, this chapter describes how the general criteria for a fuel element are determined.

The following report describes the use of airborne radioactivity surveying and analytical techniques in geologic exploration by examples of the analysis or evaluation of airborne data related to specific geologic settings. The airborne radioactivity surveying program was begun in 1949 by the U.S. Geological Survey to assist in uranium exploration.

Report presenting values of the nondimensional normal component of induced velocity throughout the flow field of a uniformly loaded lifting rotor operating in the upper half of the helicopter speed range in the form of graphs and tables. The results obtained should be useful for estimating the induced velocity distribution about lifting rotors in general and for synthesizing the distributions over the rotor disk for the case of any specified non-uniform loading.

The results of laboratory studies on sodium carbonate ion exchange are shown. The effect of salt concentration, uranium concentration, and possible interference with ion exchange from vanadium, molybdenum, sulfate and chloride are discussed. Various elution systems and the effect of residual uranium are described. A short discussion of ammonium carbonate ion exchange is also presented. (auth)

This report describes the operation of the fuels preparation department for the month of April 1958. Manufacturing, employee relations, process development, plant improvements, and financial operations are described.

Annual report submitted by the Boy Scouts of America to Congress describing highlights from 1957, activities, organizational leadership, and other information about scouting programs.

Report issued by the Bureau of Mines over studies conducted on manganese deposits of Aroostook County, Maine. Descriptions of the deposits, and the results of the study are presented. This report includes tables, maps, illustrations, and photographs.

Preface: The Fuel Elements Conference held in Paris, France, November 18 to 23, 1957, under the joint sponsorship of the U.S. Atomic Energy Commission and the French Commissarat à l'Energie Atomique (CEA), provided an intensive review of fuel-element fabrication practices and behavior of fuel elements under in-pile irradiation and when subjected to corrosive media.

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Annual report submitted by the Girl Scouts of the United States of America to Congress describing highlights from 1957, activities, finance, organizational leadership, and other information about scouting programs.

This is the monthly report for the Hanford Laboratories Operation, March, 1958. Metallurgy, reactor fuels, chemistry, dosimetry, separation processes, reactor technology, financial activities, visits, biology operation, physics and instrumentation research, and employee relations are discussed.

Papers are presented in the following major categories: applied metallurgical research, natural-uranium metallic fuel elements, enriched-uranium metallic fuel elements, nonmetallic fuel elements, corrosion of U alloys, irradiation effects on U, its alloys, and its compounds, and Pu fuel elements. (M.H.R.)

This report gives an information about the substation present in the state of Alaska from the day it was established through the year 1955.

Biweekly, comprehensive compilation of decisions, reports, public notices, and other documents of the U.S. Federal Communications Commission.