Pressures were simultaneously measured at 54 orifices distributed over the midspan section of a 5 by 30-inch rectangular model of the NACA 4412 airfoil in the variable-density tunnel. These measurements were made at 17 angles of attack from -20 degrees to 30 degrees for eight values of the effective Reynolds number form approximately 100,000 to 8,200,000. Accurate data were thus obtained for studying the variation of pressure distribution with Reynolds number. These results on the NACA 4412 section indicated that the pressure distribution is practically unaffected by changes in Reynolds number except where separation is involved.

"Equations and design charts are given for predicting the downwash angles and the wake characteristics for power-off conditions behind plain and flapped wings of the types used in modern design practice. The downwash charts cover the cases of elliptical wings and wings of taper ratios 1, 2, 3, and 5, with aspect ratios of 6, 9, and 12, having flaps covering 0, 40, 70, and 100 percent of the span. Curves of the span load distributions for all these cases are included" (p. 1).

Technical report with short reports on (1) P-9 recovery from UO2F2 solution; (2) Correlation of theories on action of radiation on matter; (3) Literature surveys on organic compounds and on chemistry of UO2F2; (4) effect of radiation on organic compounds; and (5) Effect of radiation on 100 area construction materials.

This paper contains a description of the apparatus and theories of the methods successfully used for determining the fast decay periods of near-critical assemblies. The methods described are: (1) the modulation method and (2) the delayed coincidence or Rossi method

All of the available evidence leads to the view that the 5f electron shell is being filled in the heaviest elements giving rise to a transition series which begins with actinium in the same sense that the rare earth or 'lanthanide' series begins with lanthanum. Such an 'actinide' series is suggested on the basis of evidence in the following lines: (1) chemical properties, (2) absorption spectra in aqueous solution and crystals, (3) crystallographic structure data, (4) magnetic susceptibility data and (5) spectroscopic data. The salient point is that the characteristic oxidation state (i.e., the oxidation state exhibited by the member containing seven 5f and presumably also by the member containing fourteen 5f electrons, curium and element 103) is the III state, and the group is placed in the periodic table on this basis. The data also make it possible to give a suggested table of electronic configurations of the ground state of the gaseous atom for each of the elements from actinium to curium inclusive.

"An investigation has been made in the Langley 16-foot high-speed tunnel to determine the propeller-section characteristics by measuring the pressure distribution on the airfoil sections of a rotating propeller. The pressures were measured at nine radial stations on an NACA 10-(3)(08)-03 design two-blade propeller. This paper presents the results of the pressure measurements in the form of normal-force and moment coefficients and covers a range of nominal angle of attack (simple blade element theory) from 0 degrees to 4 degrees for a section Mach number range of approximately 0.6 to 1.15 for the outboard stations and approximately 0.3 to 0.6 for inboard stations" (p. 1).

On July 14, 1949, and office memorandum was written about operations of a reprocessing building on the Hanford Site being suspended due to the mishandling of some plutonium powder. The letter describes the process of decontamination of the building surfaces, and the ventilation of the rooms of that building. It also describes the problem with the ventilation fans due to increased temperature and pressures.

A solution of Pu was prepared for use in a re-investigation of the present 49 titration method. Three 500 microliter portions of the sample were dried and ignited to PuO{sub 2}. From the weight of the residue and the impurity analysis, the concentration, in g/l, of the solution was found to be 222.2, 221.5, and 222.5; average of 222.0. The six samples submitted to the control laboratory in Bldg. 231 were reported as: 219.3, 223.6, 221.5, 220.9, 222.3, and 228.2 (re-run 229.3); average of 222.6 g/l. The 234-5 Laboratory reported: 228.2, 233.3, 220.2, 236.1, 225.2 (re-run 220.6), and 227.9; average of 227.3 g/l. Since the standardization was carried out on April 13, the 231 Lab received its samples on May 11, and the 234-5 Lab received their samples on May 23, a correction for increase in concentration due to decomposition of the water by alpha particles and evaporation was calculated. It was determined that the results reported by the 231 Lab were very consistent (except for one determination) and that the average value agreed with the gravimetric determination. The average results from the 234-5 Lab are 2% higher than the gravimetric results. Further studies are being made on the chemical …

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"An investigation has been made in the Langley 9- by 12-inch super-sonic blowdown tunnel at Mach numbers of 1.62 and 1.96 of a partial-span body with one tail surface, designed for use on the Hughes Falcon (MX-904) missile. The present paper extends the work reported in NACA-RM-SL50E10. Force and moment data including elevator hinge moment were obtained for the conditions of the tail in the presence of a small segment of the fore-shortened body, in the presence of a semi-span body and attached to a semi-span body, and for the condition of the foreshortened semi-span body alone" (p. 1).

Analysis of the problem of accelerating ions in a Thomas cyclotron has been confined almost entirely to the integration of various equations of motion (for single particles) for which a complete field description is necessary. In contrast, the problem of principal interest to rf system engineers concerns the gross transfer of electrical energy from an rf generator into an accelerated beam.

NpC and Pu{sub 2}O{sub 3} have been identified by x-ray diffraction. NpC is face-centered cubic, NaCl structure with a = 5.004 {+-} 0.005 A Pu{sub 2}O{sub 3} is isomorphous with the hexagonal ''A form'' for the rare earth sesquioxides with a = 3.840 {+-} 0.004 A; c = 5.957 {+-} 0.006 A and has essentially the same atomic parameters at La{sub 2}O{sub 3}. The lattice dimensions are smaller than predicted for pure Pu{sub 2}O{sub 3}, implying that the average oxidation number of plutonium is between (III) and (IV).

The following report describes the crystal structures of NpC and Pu2O3 identified by x-ray diffraction.

From abstract: "The variation of the reactivity of a pile as a function of width of a transverse gap is obtained. The method involves first finding the boundary condition satisfied by the flux at the gap face. This, in principle, provides enough information for a complete solution of the pile equations. A method for calculating the reactivity change is presented. The calculated reactivity is compared with experiment and a brief discussion of the validity of the approximations is given."

This quarterly progress report details the ongoing research happening at the Oak Ridge National Laboratory. In particular, this report discusses the current status of the Homogenous Reactor Experiment, boiling reactor and slurry studies, and general homogenous reactor studies.

Report presenting an investigation to determine the effects of dual-rotation propeller operation at high thrust on the static longitudinal stability characteristics of a semispan powered model representing a twin-engine airplane configuration with flaps retracted. Stability and trim changes associated with an extreme constant power conditions were greatly dependent on tail height and vertical location of the center of gravity. Results regarding basic data, effects of power on overall stability and trim, and tuft-grid flow surveys are provided.

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The effects of oxidation and irradiation on the microsurface structure of pile graphite have been investigated by measuring the surface area and pore size distribution of several samples. The results obtained for both oxidized and irradiated graphite samples indicate that changes in surface characteristics which occur are determined by the flux, temperature of irradiation, and gaseous atmosphere in which the radiation takes place.

Abstract: In one of the final stages of the process at the Mallinckrodt Uranium Refining Center, a 45 per cent nitric acid solution at about 170 F is used to pickle the calcined magnesium fluoride scale off the uranium derbies. The increase in the fluoride-ion content of the bath tends to promote corrosion of the Type 347 stainless tanks. This attack becomes excessive if 0.3 g/liter of fluoride ion or more is present. It was found that if aluminum ion is added to the solution the corrosiveness of the bath can be controlled. Two or three times as much aluminum ion as fluoride ion present is found satisfactory at 170 F. Indications are that the tying up of the fluoride-ion by the complexion [AlF6]8 is responsible for the corrosion control.

"The effects of elevator deflections from 0 degrees to -20 degrees on the force and moment characteristics of a 1/20-scale model of the Convair F-102 airplane with chordwise fences have been determined at Mach numbers from 0.6 to 1.1 for angles of attack up to 20 degrees in the Langley 8-foot transonic tunnel. The configuration exhibited static longitudinal stability throughout the range tested, although a mild pitch-up tendency was indicated at Mach numbers from 0.85 to 0.95. Elevator pitch effectiveness decreased rapidly between the Mach numbers of 0.9 and 1.0, however, no complete loss or reversal was indicated for all conditions tested" (p. 1).

Calculations are presented for the estimated minimum critical mass of Pu that would be allowed in Hood No. 5 and the filter boat cleaning and testing hood of the Plutonium Finishing Plant. Hood No. 5 contains the overflow tank and two vacuum traps. Limits are given for several pile exposure rates. These limits do not allow the approach of personnel into Hood No. 5 when these vessels are full.

Methods for the determination of plutonium and uranium in highly radioactive scrup dissolver solutions have been developed. Plutonium was separated from the dissolver solutions by solvent-extraction and ion-exchange techniques and determined by potentiometric titration. Uranium was separated by ion exchange and determined by potentiometric titration. Solutions that were similar to the actual dissolver solutions and that contained known amounts of plutonium and uranium were analyzed by these methods. Evaluation of the data secured for the determination of plutonium and uranium by the methods given herein indicated that, within the limits of the precision of the methods, there was no bias. The precision of the data obtained for the determination of plutonium, expressed as the relative standard deviation, was better than 2% for plutonium in the concentration range of 0.27 to 0.64 mg/ml. The precision for uranium was estimated to be about 0.2% for uranium concentrations of 425 mg/ml. These methods and the data obtained by then are discussed in this report; the procedures are appended.

Part I. Experimental Reactors: The effect of prompt-neutron lifetime upon reactor safety was investigated for the HRT. It was found that for a given pressure rise the allowable rate of reactivity addition was relatively insensitive to the average prompt-neutron lifetime, although the rate de creased somewhat with decreasing lifetime for the higher pressure rises. With only source neutrons present and the reactor initially subcritical, the allowable rate was practically independent of the initial value of k£. For a core-pressure rise of 400 psi, the corresponding rate of reactivity addition was about 0.8% per second; for a pressure rise of 4000 psi, the rate was 2.5 to 3.0% per second. Part II. Thorium Breeder Reactor: An economic study of one-region thorium breeder reactors was completed. Where possible, the process characteristics and cost factors were the same as those used previously in studies of two-region-type reactors. The mini mum-cost reactor is about 12 ft in diameter, operating with 260 g of thorium per liter on a chemical processing cycle of about 450 days. The ratio of U232 to U233 produced is approximately 2 x 10~4 VIM in the minimum-cost one-region system, compared with 4 x 10 5 in the two-region system. The …

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