The problem of shimmy of a castering wheel, such as the nose wheel of a tricycle gear airplane, is treated analytically. The flexibility of the tire is considered to be the primary cause of shimmy. The rather simple theory developed agrees rather well with previous experimental results. The author suggests that shimmy may be eliminated through a suitable choice of landing gear dimensions in lieu of a damper.

From Summary: "A simplified approximate theory is presented by means of which the laminar boundary layer over an insulated two-dimensional surface may be calculated, a linear velocity profile being assumed, and an estimate made of its effect in changing the pressure distribution over the profile upon which the boundary layer is formed. Skin friction is also determined. Comparisons of results from this theory are made with experimental results at a Mach number of 6.86 and a Reynolds number of 980,000."

Report issued by the Brookhaven National Laboratory discussing the Emergency Radiological Monitoring Team. Equipment, training, and personnel required for the team is presented. This report includes tables, illustrations, and photographs.

"Two methods of using the concept of linearized characteristics are derived for the one-dimensional unsteady flow in a tube that is rotated about an axis perpendicular to the axis of the tube. One of the methods correponds to that used by Ferri in his basic work on the subject. Solutions are made by both methods for boundary conditions that allow analytic solutions" (p. 1).

Report presenting burst testing conducted on several designs of sound disks and disks with defects. Results were compared with tensile strength, tensile ductility, and notch tensile strength. The main purpose of the investigation was to determine the extent to which disk strength can be increased by increasing tensile strength, to investigate the extent to which a correlation exists between disk strength and mechanical properties, and to present data on the influence of several types of stress concentration on the strength of disks made from ductile and brittle materials.

A report regarding the distribution of the Leached Zone of the Bone Valley Formation, Land-Pebble Phosphate Field, Florida.

Report presenting force testing in the high-speed tunnel to determine the effect of a simulated propeller slipstream on the aerodynamic characteristics of an unswept wing panel with and without nacelles. Lift, drag, and pitching moment were measured for a range of angles of attack and Mach numbers.

Abstract: A study has been conducted to provide data on the loss of germanium from ashed lignite samples. The lignite samples, of known germanium content, were ashed at various temperatures as high as 1000 °C with varying rates of heating and varying amounts of surface area of the lignites. The results indicate that no germanium was volatilized during the various ignitions.

Report presenting a study to establish the effect of solvents on boundary lubrication by silicones. Boundary-lubrication data were obtained which are considered substantiating evidence for a hypothesis that, in solutions of solvents blended with silicones, the silicones form a closely packed and oriented absorbed film on ferrous surfaces. Results regarding room-temperature lubrication experiments, elevated-temperature lubrication experiments, low-temperature physical behavior, and effect of conventional lubrication additive are provided.

Report presenting an analysis to give a qualitative picture of the effects of wing sweep on the upwash at the propeller airplanes of multi-engine airplanes. The method was applied to two hypothetical airplanes of the high-speed long-range type, one with an unswept wing and the other with a sweptback wing. Results regarding wing upwash, total upflow for the airplanes, upwash contribution of the airplane components, nacelles inclined, and aerodynamic exciting parameter, nacelles inclined are provided.

"A structural theory is developed for the analysis of thin multicell wings with straight spars and perpendicular ribs. The analysis is intended to be suitable for supersonic wings of low aspect ratio. Deflections due to shearing strains are taken into account" (p. 1).

"With the aid of the method of small oscillations which was used successfully in the investigation of the stability of laminar velocity distributions in the presence of two-dimensional perturbations, the excitation of the unstable perturbations for the Hartree velocity distributions occurring in plane boundary-layer flow for decreasing and increasing pressure is calculated as a supplement to a former report. The results of this investigation are to make a contribution toward calculation of the transition point on cylindrical bodies" (p. 1).

Report presenting an investigation in flight at free-stream Mach numbers up to 0.77 to determine the effect of a laminar boundary layer and thin and thick turbulent boundary layers on the chordwise pressure distribution over an airfoil in the presence of shock at full-scale Reynolds numbers. Boundary-layer and pressure-distribution measurements were made on a short-span airfoil built around the wing of a fighter airplane.

Report presenting a flight investigation on a four-engine bomber to determine the effect of transient wing response in rough air on the acceleration measurements at the center of gravity of the airplane. Flights occurred in clear-air turbulence for two speed and two weight conditions. The results indicate that transient-response effects on total aerodynamic load are small for the test airplane.

Report presenting an investigation in order to study the characteristics of flow in the vicinity of a rectangular wing of aspect ratio 0.25 with a modified flat-plate airfoil section. The investigation was conducted using photographs of a tuft grid located at a number of chordwise positions along the airfoil and behind the trailing edge. Results regarding the force-tests, formation of vortices and vorticity distribution in the wake, location of vortex cores, and chordwise growth of lift are provided.

Report describing the geology of the land-pebble phosphate district on the Gulf Coastal Plain of Florida. This district is mapped out and the formation of land-pebble phosphate deposits is shown.

From introduction: This report summarizes the results of diamond-drill and wagon-drill exploration by the U. S. Geological Survey in the Yellow Cat area from October 9, 1951, to May 22, 1952. The Yellow Cat area is about 10 miles southeast of Thompsons, Grand County, Utah. It is accessable by two graded roads which leave U. S. Highway 50 at points 5 miles east of Thompsons and 7 miles west of Cisco, Utah. A sampling plant and purchasing depot, belonging to the United States Vanadium Co., is at Thompsons. The explored ground includes about 8 square miles principally in T. 22 S., R. 22 E., and the northern part of T. 23 S., R. 22 E., Salt Lake meridian (fig. 1). Altitudes in the area range from about 4, 600 feet to 5, 100 feet (datum is assumed but is approximately correct), and the relief is moderate.

Note presenting an application of the well-known analogy between electrical and mechanical systems to the calculation of stresses and deflections of beams. The main objective of the paper is to give an explanation of the analogies in a basic manner which will enable a structural engineer to understand the process of designing the electrical circuits. Analogies are given for beams in bending and torsion with static loads and in vibrational motion.

Note presenting an extension of the Kármán-Pohlhausen method to sixth-degree velocity profiles for determining the characteristics of the compressible laminar boundary layer over an adiabatic wall in the presence of an axial pressure gradient.

"A method is presented for finding an mth-degree polynomial that passes through a specified point with (m - j) specified derivatives (l ≤ j ≤ m) and is a least-squares polynomial for other points spaced at unequal intervals of the independent variable" (p. 1).

Note presenting a method for the determination of the time lag in pressure measuring systems incorporating capillaries. The method can be used to select, design, or redesign a pressure measuring system to meet the time requirements of a particular installation. Experimental data are shown and a step-by-step sample application is presented.

Report discussing the leaching of uranium, radium and lead from oxidized black Katanga pitchblende. Results of leaching are included.

This is a map, scale 1:24,000, of the photogeology and surface geology of the Colorado Plateau Area.

Report discussing the investigation of radioactivity at the Copper Creek related to copper mineralization in sedimentary rocks. The radioactivity probably originated from uranium relating to bornite and malachite.