This report discusses methods of producing aluminum nitrate for the Redox process. Large amounts of aluminum nitrate are consumed during the Redox process, so this report explores preparation of this material through the dissolution of hydrated aluminum oxide in nitric acid.

From abstract: "The chemical analyses of graphite test bars obtained from National Carbon Company and the analyses performed by the Hanford Works Laboratories Division do not correlate significantly with the test pile results, nor do the chemical analyses obtained from National Carbon Company agree with those done in the Handford Works Laboratories. Chemical results obtained at Hanford on samples taken lengthwise from individual bars correlated significantly with the individual test pile results."

Abstract. The separation of uranyl nitrate from aqueous solutions of 0.635 M thorium nitrate, 3 M nitric acid and 3 M calcium nitrate by extraction with organic solvents has been investigated. Solvents which gave good separations were 2-tthyl hexyl acetate, ethyl benzoate, n-butyl either and beta-beta- dichloroethyl ether. In general, higher esters, ethers and alcohols are better for separating uranium from thorium that the lower homologues. Several solvents were tested at lower nitric acid concentrations. Dibutyl cellosolve gave a very good separation when the solution was 0.1 M nitric acid. Of the solvent mixtures studied that of equal parts of n-butyl ether and dibutyl cellosolve gave a good separation.

Introduction. It has been known for a long time that thorium is precipitated by oxalic acid in acid solutions, but a survey of the literature showed no study of the limits of the acidity and oxalic acid excess which yield quantitative results. V. I. Spitzin reports on the solubility of thorium oxalate in varying concentrations of several acids, but the effect of an excess oxalic acid is not included. Since solutions are sometimes presented for analysis that contain more than the recommended two per cent mineral acid, it would be advantageous to be able to quantitatively remove the thorium without otherwise altering the solutions. This was especially of interest in solutions containing bismuth, since it was hoped that some amounts of thorium could be precipitated in nitric acid solutions containing large quantities of bismuth. In removing the bismuth, first by a bismuth oxychloride precipitation, thee is every opportunity for carrying of the thorium.

Abstract. Successive approximations ae obtained from transport theory for the neutron distribution around a black sphere surrounded by a spherical gap and a non-absorbing medium extending to infinity. Six cases are calculated numerically to show the difference between this treatment and simple diffusion theory. The extrapolation distance and a quantity that is essentially the thermal utilization are calculated in different approximations. It is found that the neutron density in the gap, instead of being a constant as predicted by the simple theory, may vary by a factor of one-third in cases of practical interest.

The following report provides information conducted during histological observations made on the anatomy of female mice who have been exposed to 400 arbitrary units of slow neutrons.

Compilation of the papers presented at a NACA conference on transonic airplane design, including stability and control and configurations with extreme sweep. From Introduction: "The purpose of this conference was to convey to those involved in the study of the aerodynamic problems of transonic aircraft these recent research results and to provide those attending an opportunity for discussion of the results."

Report presenting measurements using the NACA wing-flow method of the lift, pitching-moment, and hinge-moment characteristics of a 35 degree sweptback NACA 65-009 airfoil of aspect ratio 3.04 with a full-span 1/4-chord unsealed plain flap. The tests were carried out at a range of Mach numbers, Reynolds numbers, angles of attack, and flap deflections. Variations of lift and pitching moment with angle of attack or flap deflection were approximately rectilinear at all Mach numbers for moderate angles of attack and flap deflections.

Report presenting the results of testing in the transonic range of four flutter airfoils attached to a freely falling body. Failures of the airfoils were metered and recorded in order to determine the Mach numbers and altitudes of failure.

From Summary: "The results of an experimental investigation of an NACA submerged-air-inlet system on a 1/5-scale model of a fighter airplane are presented. Preliminary development tests were conducted to select the optimum entrance configuration. Duct-system total-pressure losses and pressure distributions over the lip and ramp of this air intake were obtained."

Report presenting a flight investigation conducted to establish the heat requirements for ice prevention on aircraft windshields mounted on the forebody of an airplane at several angles. Electrically heated windshields were used in order to provide accurate measuring of heat input to the windshield. Results regarding the quantity of heat provided, amount of water collection, ideal windshield angle, ranges in airplane velocity, and icing conditions are provided.

From experience gained by NACA test pilots in flying at high subsonic Mach numbers and from interpretation of the data obtained, some general precautionary rules for test flying near sonic Mach numbers have been formulated. The reasons for these rules are discussed and observations are made with respect to the hazards arising from undesirable stability and control characteristics which have been noted in test flights of various airplanes. This paper, although written primarily for the attention of test pilots, contains general information of interest to those who are concerned with various phases of flight testing near sonic Mach numbers.

Report presenting an investigation to obtain the pressure distribution over a sharp-nose body of revolution with a circular-arc profile and fineness ratio 6 at transonic speeds using the NACA wing-flow method. Results regarding the variation of pressure coefficient with Mach number, pressure distributions along the body axis, pressure drag, and effects of interference and horizontal gradient are provided.

Report presenting an investigation to study cowling-spinner combinations based on the NACA 1-series nose inlets and to obtain systemic data for one family of approximately ellipsoidal spinners. 11 of the spinners were also tested in various combinations with 9 NACA open-nose cowlings, which were also tested without spinners. Results regarding flow over spinners, internal flow, external flow over cowling, critical Mach number characteristics, envelope values, and cowling section are provided.

"In the present paper an analysis is made of the compressible-flow variations occurring in heat-exchanger passages. The results of the analysis describe the flow and heating characteristics for which specific flow passages can be treated as segments of generalized flow systems. The graphical representation of the flow variations in the generalized flow systems can then be utilized as working charts to determine directly the pressure changes occurring in any specific flow passage. On the basis of these results, working charts are constructed to handle the case of air heated at constant wall temperature under turbulent-flow conditions" (p. 1).

Report presenting an approximate method for calculating the interference pressure distribution at zero lift of a symmetrical sweptback wing mounted on a circular cylindrical body with the chord plane of the wing passing through the axis of the body. An example is provided using a circular cylindrical body and an untapered wing with 60 degrees of sweepback.

Tests were made to determine the loss in exhaust-jet thrust and engine power resulting from the insertion of an exhaust-gas-to-air heat exchanger in a jet-type exhaust stack of an aircraft engine. The thermal performance of the heat exchanger was also determined.

Report presenting a wind-tunnel investigation of a semispan pointed wing of aspect ratio 1.7 with 60 degree leading-edge sweepback and 30 degree trailing-edge sweepforward with a control surface. The purpose of the investigation was to determine the effectiveness of flap-type controls at transonic and supersonic speeds. Results regarding the wing characteristics and control-surface characteristics are provided.

Report presenting testing of a cambered and twisted wing with constant-chord elevons with a slender fuselage to determine the longitudinal and lateral control from the elevons for a range of Mach numbers. Results regarding lift, drag, pitching-moment, and rolling-moment characteristics for various elevon deflections are provided.

Report presenting the results of lift, drag, and pitching-moment measurements on a model of the Douglas D-558-2 airplane at a range of angles of attack and Mach numbers. The model was also tested with two different sets of chordwise fences in order to investigate their effects on force and moment characteristics at high speeds.

"A method is presented for predicting the amplitude and frequency, under certain simplifying conditions, of the hunting oscillations of an automatically controlled aircraft with lag in the control system or in the response of the aircraft to the controls. If the steering device is actuated by a simple right-left type of signal, the series of alternating fixed-amplified signals occurring during the hunting may ordinarily be represented by a "square wave." Formulas are given expressing the response to such a variations of signal in terms of the response to a unit signal" (p. 487).

The variation of pressure distribution is calculated for a two-dimensional supersonic airfoil either experiencing a sudden angle-of-attack change or entering a sharp-edge gust. From these pressure distributions the indicial lift functions applicable to unsteady lift problems are determined for two cases. Results are presented which permit the determination of maximum increment in lift coefficient attained by an unrestrained airfoil during its flight through a gust. As an application of these results, the minimum altitude for safe flight through a specific gust is calculated for a particular supersonic wing of given strength and wing loading.

From Summary: "A theoretical investigation of the velocity profiles for laminar mixing of a high-velocity stream with a region of fluid at rest has been made assuming that the Prandtl number is unity. A method which involves only quadratures is presented for calculating the velocity profile in the mixing layer for an arbitrary value of the free-stream Mach number. Detailed velocity profiles have been calculated for free-stream Mach numbers of 0, 1, 2, 3, and 5."

A finite-difference method previously presented for computing elastic stresses in rotating disks is extended to include the computation of the disk stresses when plastic flow and creep are considered. A finite-difference method is employed to eliminate numerical integration and to permit nontechnical personnel to make the calculations with a minimum of engineering supervision. Illustrative examples are included to facilitate explanation of the procedure by carrying out the computations on a typical gas-turbine disk through a complete running cycle. The results of the numerical examples presented indicate that plastic flow markedly alters the elastic-stress distribution.