Report discussing an adapter which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.

From Summary: "Bearing tests of AM-3S, AM-52S, and AM-C57S magnesium-alloy sheet in various thicknesses and tempers were made. Bearing yield and ultimate strengths were determined and compared for various edge distances and for various ratios of loading-pin diameter to sheet thickness. Tensile strengths were determined and ratios of average bearing yield and ultimate strength to tensile strength are given."

Report issued by the Bureau of Mines over briquetting of coal for development of more effective fuel. Materials, equipment, and processes are discussed. This report includes tables, illustrations, and photographs.

Abstract. The precipitation of Pa233 with MnO2 from a solution of thorium nitrate has been studied in some detail and seems quite satisfactory up to 36 gm Th(HO3)4 4H2O per 100 cc solution. The concentration of Pa233 with respect to the manganese dioxide carrier and the thorium precipitated with the carrier appears to be accomplished quite well by either a series of MnO2 cycles or thorium iodate cycles. Volatility methods for both the separation of Pa233 from the original thorium and for its separation from MnO2 are now under investigation. It has been decided that thorium carbonate will the the thorium compound used in the pile at Site X.

From abstract: "This paper gives a method for determining Uranium using sodium cresotate as a colorimetric reagent. A precision is obtained of better than 2%. In carrying out analyses for Uranium in corrosion products by existing methods such as ignition to the oxide, silver reductor, or titration with ceric sulfate, it became apparent that a rapid, fairly accurate method for determining uranyl ion would be of great value. Such a method is described in this paper. The most logical color to use is that given by the ferrocyanide complex, but upon studying this, it proved to be unsatisfactory. Sodium salycilate also gives a color which has been used with some success, but its color appears to fade and is not very sensitive. A similar compound, sodium cresotate, was found to give an orange-red color and is the reagent used in the method to be described."

The following sources of contamination in cooling water of the P-9 plant are considered: (1) Fission recoils, (2) Corrosion of metal, (3) Recoil from aluminum, (4) Induced activity in the water. It is found that for a P-9 plant of 3.5 x 10(4) KW contamination of the river at "X" should not exceed the .1 r criterion unless coating failure occurs. Tables of the amount of coating failure permissible are given as a function of holdup time.

Describes the results of a scientific study on the effect of summer weeds on crops (mainly sugar beets and tomatoes) and the use of the beet leafhopper to reduce their growth in the San Joaquin Valley in California.

Report presenting porpoising tests of three rudimentary models composed of two V-bottom planing surfaces in tandem and fitted with a tail plane. The upper and lower branches of the upper trim limit of stability were determined for three angles of dead rise and two depths of step.

Report presenting data on the effect of exhaust back pressure on engine power for 14 aircraft engines. The data showed that the effect of exhaust back pressure on engine power varies with engine speed, range of back pressure and manifold pressure involved, and engine type. The only method of accurately determining the effect of back pressure on engine power than can currently be recommended is to test the specific engine type at the engine speed for which data are desired.

Report presenting an investigation to determine the effects of wing loading and altitude on lateral stability and control in the free-flight tunnel. The results of flight tests of the model were correlated with calculated stability boundaries, and an effort was made to determine for each loading condition the airplane configuration that gave the best flight characteristics. Results regarding the lateral stability, lateral control, and general flight behavior are provided.

Describes the tools and tasks of the engineer soldier. Includes a proficiency test for soldiers in training.

"A mathematical procedure is herein developed for obtaining exact solutions of shear-lag problems in flat panels and box beams: the method is based on the assumption that the amount of stretching of the sheets in the direction perpendicular to the direction of essential normal stresses is negligible. Explicit solutions, including the treatment of cut-outs, are given for several cases and numerical results are presented in graphic and tabular form. The general theory is presented in a from which further solutions can be readily obtained" (p. 1).

Report presenting values of the lateral-stability derivative, the rate of change of yawing-moment coefficient with yawing angular velocity, contributed by the wing, the fuselage, and the vertical tail, which have been determined for a midwing airplane model by the free-oscillation method.

Report presenting the results of an investigation of the fatigue characteristics of spot-welded 24S-T aluminum alloy. The static shear strength of spot welds in lap joints of 24S-T alclad increases with increasing sheet thickness for thicknesses in the range of 0.025 inch to 0.032 inch.

Report issued by the U.S. Bureau of Mines discussing the organization of the Coal-Mine Inspection Division. The inspection procedures and work accomplished are presented. This report includes tables, illustrations, photographs, and a map.

Report presenting flight tests of an all-movable vertical tail of reduced area of the Fairchild XR2K-1 airplane. Results are in agreement with previously obtained data on a larger all-movable tail. Results regarding rudder effectiveness, directional stability, rudder-free lateral motion, rudder hinge moments, and areas of future research are provided.

Report presenting a series of tests of the Brewster XSBA-1 airplane conducted to determine the effect of various tail modifications. The current report describes an investigation of flying qualities of the airplanes with its original tail surfaces. Testing regarding longitudinal stability and control and stalling characteristics are provided.

Report presenting force tests and measurements of the pressure distribution over the elevator and forward part of the fuselage on a flying model of the Curtiss XP-55 airplane in the full-scale tunnel. The results of the elevator pressure measurements are given in this paper. Results regarding chordwise pressure distributions, span-load distribution, and normal-force coefficients are provided.

Report presenting experimental data on the distribution coefficients of technical xylidines for the system gasoline-water. The distribution coefficient is defined as the ratio of the concentration of xylidines in the gasoline layer to that in the water layer. Results regarding the effect of concentration of xylidines, effect of aromatic content of fuel, effect of sea water, and effect of temperature are provided.

Report presenting an investigation to determine the loci of possible positions of a heavy bomber in space following a 12-second interval.

Report presenting testing to determine the low-temperature solubility of technical xylidines in aviation gasoline. Testing included measuring the cloud point, or incipient separation temperature, at several concentrations of technical xylidines in a 65-octane-number clear gasoline without aromatics and with aromatics added in various percentages up to 15 percent by volume and a grade 130, specification AN-F-28, amendment 2, gasoline.

Report presenting results of mechanical tests of macerated phenolic molding material. The following tests were performed: static tension, compression, torsion, and flexure tests; long-time creep tests at different stresses, tests for time to fracture under long-continued constant load; Izod and Charpy impact tests; bending fatigue tests at different ranges of stress; rotating-beam fatigue tests at different speeds of testing; rotating beam fatigue tests of notched specimens; and torsion fatigue tests.

Front: Text describes action on various war fronts: China, Air Offensive, Aleutians, Russia, North Africa, Southwest Pacific. Maps: Global map of war fronts; China, Burma, Mongolia, Japan. Photographs: Nazi sub sank after charged by The U.S. Coast Guard Cutter Spencer; The enterprise "Workhorse of War"; Yanks in India; Six B-24's of the U.S. Army Eighth Air Force attacking the port at Kiel in northern Germany. Back: "Secret" weapons are the little drops of information that you could give away! [Illustrations of the importance of keeping a military secret.]

Front: Text describes action on various war fronts: Plans, Russia, Italy, Far East, Southwest Pacific, Argentina. Maps: The Eastern Front; large world map shows United Nations, Axis and Axis occupied areas, countries with Axis relations broken, and neutral countries. Photographs: Gangway, I'm a choo choo train [Army jeep pulls a freight car] -- Member of Chinese Expeditionary Force trains at a U.S. Army base in India -- Soldiers move material into place to build a bridge -- Chinese soldier simultaneously receives immunization shots in both arms. Back: The Making of a U.S. Bluejacket. Text and 25 photographs illustrate the training of the Naval personnel.