This report has two parts to it discussing mineralogical examination of pitchblende concentrates and nitric acid digest residues. Part I gives the results of a cursory examination with the petrographic microscope of samples of pitchblende concentrates and residues to see if there is a relationship between the mineral composition of the samples and the filterability of the residue. Part II gives a revaluation of the data in Report BMI-241 on the mineral composition of two residues from the nitric acid digestion of pitchblende concentrates at the Rallinckrodt Chemical Works.

Technical report outlining the investigation of corrosion on MTR type fuel elements for the Shielding Reactor in filtered water. Report includes two basic types of protection: element pretreatment by either anodizing or alodizing, and solution control using nitric acid to maintain a pH of 5.5 to 6.5 or the addition of 60 ppm sodium chromate as an inhibitor. [From Abstract]

Report presenting the drag-reducing effectiveness of bleeding air to the base region of blunt-base bodies in a supersonic stream was investigated at a Mach number of 1.91.

Report presenting flight test data obtained with two Bell X-1 airplanes, one with an 8-percent-thick wing and a 6-percent-thick tail and one with a 10-percent-thick wing and an 8-percent-thick tail. Data was obtained at a variety of Mach numbers, lift coefficients, and test altitudes. Results regarding stick-fixed stability and trim changes are provided.

Report presenting an investigation of a 1/21-scale model of the Chance Vought F7U-3 airplane in the 20-foot free-spinning tunnel to determine the erect and inverted spin and recovery characteristics for combat loading in the clean condition. Results regarding erect spins, inverted spins, spin-recovery parachutes, and recommended recovery technique are provided.

Report presenting testing of several turbojet engines with both constant- and variable-area nozzles to extend full-scale nozzle performance to higher exhaust-nozzle pressure ratios and to investigate the effects of constant- and variable-area nozzles on turbojet-engine operation. Results regarding the different types of nozzles are provided.

Memorandum presenting an investigation to determine the effect of mass distribution on the dynamic lateral stability and control characteristics of a model with a 60 degree triangular wing in the free-flight tunnel. Flight tests and calculations were made for five different loading conditions. Results regarding the oscillatory stability, lateral control, and general flight behavior are provided.

Report presenting a theoretical investigation to determine the effects of autopilot natural frequency on the dynamic performance characteristics of an attitude-controlled supersonic missile configuration with rate damping for a Mach number and altitude range. The autopilots considered were single-degree-of-freedom systems with a fixed damping ratio and various natural frequencies.

"Experimental data have been obtained of the rolling effectiveness of several all-movable wing configurations by means of rocket-propelled test vehicles in free flight. The results are compared with some available methods of estimation. These results validate the use of the simple equation derived by a strip integration and originally presented in NACA RM L50G14b over a wide range of application as a means of estimating the rolling effectiveness of all-movable wings" (p. 1).

From Introduction: "The propulsive jet that discharges from the base of a missile body or nacelle may, by interaction with external stream, cause important drag and stability changes. This paper presents some results of recent investigations by the Lewis and Langley laboratories of the jet effect on body end pressures and drag at zero lift."

"An investigation to determine the structural damping characteristics of a full-scale airplane wing was conducted by the shock-excitation method wherein the wing was loaded to a predetermined deflection and the load suddenly released. The test specimen vibrated at its fundamental bending frequency of 1.69 cycles per second. Only the first 2 or 3 cycles showed any indication of a higher frequency being superimposed upon the fundamental bending frequency" (p. 1).

Report presenting the rates of flame propagation of four alkylsilanes as determined by the tube method. Results regarding alkylsilane flame velocities, blends of diethylsilane and n-pentane, and flame propagation theories are provided.

Report presenting an investigation by means of tests of a flying model in still air to determine the dynamic stability and control characteristics of a delta-wing vertically rising airplane in take-off, landing, and hovering phases of flight. The uncontrolled pitching motion consisted of an unstable oscillation which was more unstable with a rearward than with the normal center-of-gravity location.

"A light-source power unit has been developed that provides reliable trigger, and easy synchronization with rotating elements or electric impulses. When used with conventional spark gaps and flash tubes, this power unit provides a light pulse of high intensity and short duration" (p. 1).

Report presenting a wind-tunnel investigation to determine the effects of a section modification on the aerodynamic characteristics of a wing with 35 degrees of sweepback. The wing was modified by increasing the leading-edge radius of the NACA 64A010 section and adding a small amount of camber to the forward portion of the chord. Lift, drag, pitching-moment, and trailing-edge-flap hinge-moment characteristics of the modified wing are compared with results from the original wing.

This report discusses the development of a method for creating leak-proof closures in aluminum sample casings in order to pass a standard bubble-test inspection.

Introduction: A limited test progress on Alloghany-Ludlum type 347 stainless steel plate which failed the Huey test (ASTN A-262-44T) has been completed.

Abstract: An evaluation is made of radioactivity logging as applied to exploration drilling on the Colorado Plateau. The compilation of data gives a preliminary insight into the possibilities of the technique being applied.

"A program of creep-rupture tests of several bars of Beryllium has been completed. The tests were made at 1200, 1400, 1550, and 1700 F. in protective atmospheres of tank helium or hydrogen. The results are given in a summary table and by creep and design curves. A description of the test set-up is included."

From introduction: "It has become desirable to develop an alternative method for the determination of lithium to serve as a stand-by method at times when the flame photometer is inoperative, or to supplement the latter in cases where a doubtful analysis requires further investigation. A method based upon the precipitation of lithium with potassium ferriperiodate was investigated because of its expected freedom from interference by aluminum."

Calculations indicative of the power loss for 75 in.radius gap splitters are given.

Technical report outlining the fabrication of twenty-five fuel assemblies and three shim-safety rod fuel sections for use in the Materials Resting Reactor Mock-Up Critical Experiments. Results show that two of the assemblies exceeded tolerance in a few of the key dimensions, but were considered acceptable and as a consequence, production was carried out with no rejects. [From Abstract]

Heat-transfer investigation conducted on cooled as well heated impulse-type turbine blades in a static cascade to determine the effect of direction of heat flow on convective heat-transfer coefficients.

A simple, light-weight, split beam optical smoke densitometer is described.