A number of considerations related to the stability of certain difference analogs of the differential equation of heat conduction and with the convergence of iteration procedures derived from implicit difference equations are presented. The operator approach is used in a manner which dispenses with the knowledge of eigenvalues. (J.R.D.)

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Advanced Water Reactor Program. The second fuel loading for the EBWR is planned as ThO/sub 2/--UO/sub 2/. Some properties of ThO/sub 2/-- UO/sub 2/ systems are presented. Fast Power Breeder Reactor Program. The development of casting techniques for EBR-1, Mark III extrusion billet cores are described. The investigation of methods for the remote refabrication of irradiated reactor fuels was undertaken with the objective of designing, constructing, and testing techniques and equipment for the refabrication of EBR-II fuels. Advanced Engineering and Development. From observations amd photographs made during disassembly operations, and from chemical, metallographic, and density measurements, it was possible to reconstruct the probable physical structure of the core after the meltdown of the EBR-1 core. A boiling experiment was performed to give preliminary information as to whether thermal decomposition or volatility would complicate the use of H/sub 3/PO/sub 4/ solution in boiling reactors. Due to the possible use of Mg as a cladding material a few preliminary corrosion tests were made with distilled water. Cylindrical, NaK-filled Zr irradiation capsules, which suddenly broke open during decanning operations following irradiation, were examined in an effort to determine the role of irradiation in these unexpected failures. Production, Treatment, and Properties of Materials. Elastic …

This report addresses the conservation laws in weak interactions.

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The use of direct refluorinntion to recover plutonium deposited in equipment by consumption and decomposition of PuF/sub 6/ gas was the subject of a brief experimental program Measurable rates of refluorination were obtained at temperatures as low as 170 C and by means of a statistically dcsigned experiment; the approximate signficance of the three variables, temperature, fluorine pressure, and fluorine flow rate, was determined. Temperature was found to be the most significant variable, and the heat of reaction based on removal rates measured from 170 to 350 C compared favorably with reported values obtained by equilibrating PuF/sub 6/ and F2 gas mixtures. At plutonium surface concentrntions below -3 mu g/cm, the rate of refluorination was found to be proportional to the plutonium surface concentration. In no case was the surface concentration decreased below 0.08 mu g/cm2. (auth)

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"Comparisons are made of experimental and theoretical zero-lift wave drag for several nose shapes, wing-body combinations, and models of current airplanes at Mach numbers up to 1.0. The experimental data were obtained from tests in the Ames 6- by 6-foot supersonic wind tunnel and at the NACA Wallops Island facility. The theoretical drag was found by use of linear theory utilizing model area distributions" (p. 1).

Report presenting results from pitot-static and hot-wire anemometer surveys at low speed of the flow over a thin, sharp-edge airfoil which simulated a flat plate. The primary purpose was to obtain detailed measurements of the flow associated with the so-called thin-airfoil type of stall. Results regarding the preliminary tests, pressure distributions, mean flow measurements, velocity fluctuation measurements, and observations and measurements of the flow in the immediate vicinity of the leading edge are provided.

Report presenting an investigation in the high-speed hydrodynamics facility to determine whether planing lift coefficient of a flat-bottom planing surface remains constant with increasing speed at the high towing speeds obtainable. The generally accepted assumption that there is no effect of speed on the lift coefficient of positive-pressure lifting surfaces is valid at least up to 170 fps.

Report presenting an investigation at Mach number 2.40 to determine the aerodynamic characteristics of plain overhang balances on flap-type controls. Testing was performed on a two-dimensional wing with three trailing-edge flaps with balance lengths of 38, 60, and 82 percent of the flap chord. The effect of wing-flap gap size were investigated for the flap with 38 percent balance.

Report presenting an experimental investigation in the flutter research tunnel on the oscillating forces and moments on a two-dimensional wing equipped with an oscillating circular-arc spoiler.

From Summary: "A simple inelastic collision model of meteor-atmosphere interaction is used and analytic relations for velocity, deceleration, size, and relative luminous magnitude of meteors are derived and expressed in dimensionless parametric form. The analysis is compared with available quantitative observations of meteor behavior and it is indicated that a large fraction of the atmospheric bombardment energy is used in eroding meteor material. The erosion from large, high-speed vehicles as they traverse the high-altitude, free-molecule portion of the atmosphere is calculated, on the assumption that the vaporization process is similar to that which occurs for meteors."

Note presenting an investigation of the vacuum and hydrogen brazing of four heat-resistant alloys with two types of high-temperature brazing alloy. The effect of time at two brazing temperatures on the 1200 degrees Fahrenheit shear strength of joints and on the base-metal properties was studied. Shear specimens of all four base alloys brazed in hydrogen with box types of brazing alloy exhibited erratic joint coverage by the brazing alloys.

An investigation of the stability and control of a high-wing transport vertical-take-off airplane with four engines during constant-altitude transitions from hovering to normal forward flight was conducted with a remotely controlled free-flight model. The model had four propellers distributed along the wing with the thrust axes in the wing chord plane. The wing could be rotated to 90 degrees incidence so that the propeller thrust axes were vertical for hovering flight. An air jet at the rear of the fuselage provided pitch and yaw control for hovering and low-speed flight.

Note presenting the impact properties of titanium carbide base cermets, some high-temperature alloys, and the intermetallic NiAl, obtained at room and elevated temperatures up to 1750 degrees Fahrenheit. The impact energies of cermets were found to increase with increased amounts of metallic binder. Results regarding the variables of drop test, impact resistance of cermets, high-temperature alloys, and comparison of cermets and alloys are provided.

From Summary: "The low-speed stalling characteristics of a large number of airfoil sections have been correlated with Reynolds number and a single airfoil ordinate near the leading edge as the correlation parameters. The correlation is appropriate only to airfoils without high-lift devices in flows of very low turbulence and with aerodynamically smooth surfaces."