The following report discusses the results of a survey that was initiated to ascertain the availability of uranium hydride in tonnage quantities.

The purpose of this report is to summarize the work done at KAPL on physical properties of high density concretes.

Report discussing progress made by the National Research Corporation in developing preparation of ductile zirconium for the month of December, 1949.

Abstract: A new feeder chute on the continuous casting apparatus, and the use of outgassed zirconium chips resulted in a stable arc and quiet pool. Ingots up to 9 1/2 inches in length were made, and some correlation between tension on the ingot and the "necking" effect was determined. Conversions of zirconium iodide to zirconium in the arc dissociation apparatus ran from 41 to 48.2 percent with a maximum of 474 grams of metal produced in 4 hours.

Abstract: A tungsten tipped electrode has been used in the continuous casting arc furnace for a 25 minute period during which a 12 inch length of ingot was made. Thermocouple junctions within the mold wall have been improved to give mold zone temperature. A total of 10 iodide dissociation runs have been conducted using feed rates of .62-22.7 lbs ZrI₄ per hour with attendant conversion efficiencies of 97.7-16.4% and zirconium yields of 255-41.2 grams per hour. A curve expressing these data for an arbitrarily selected set of conditions is presented.

Our knowledge of the properties of mesons and their interactions with nuclei has come from two sources. Studies of cosmic ray phenomena provided the earliest information. The discovery that mesons may be produced artificially by bombardment of nuclei with radiations from high energy accelerators has, on the other hand, made it feasible to undertake a wide variety of investigations under more controlled conditions than is possible in cosmic ray experiments. In such experiments mesons have been produced by high-energy protons, alpha-particles and neutrons.