The following report calculates how many neutrons are produced by the O-16([alpha]-n) reaction in a thin and uniform polonium oxide layer.

This report follows the study of a perturbation in the fringing magnetic field of a synchrocyclotron, using the computed unperturbed orbits of the modified Berkeley 184-inch synchrocyclotron, and introduces the peeler extraction to overcome limitations by using a perturbation that recedes with increasing radial amplitude.

"The split reactor of the Critical Experiment is analyzed, using a single-energy group-diffusion approximation. A further approximation is introduced in that the two halves of the reactor are treated as a parallelopipeds rather than the half-cylinders. The reactivity of the reactor is obtained as a function of the separation of the two halves, both for the 'standard' uranium concentration and for various greater concentrations."

From introduction: "This study is concerned with the shape of the electrodes of high-voltage insulator and with the method of joining them to the dielectric. The study is limited to insulators operating in vacuum, with special interest in the cases where strong magnetic fields are present. It is further limited to insulators with the high-voltage electrodes maintained at negative potential. The object of the study was to obtain information that would aid in improving the design of the insulators in two respects. First, to decrease to a minimum the number of charged particles set free which may directly or indirectly cause early failure of the insulator. Second, to increase the voltages at which partial or complete flashovers occur. Therefore, experiments were made to determine the principal phenomenon which have as their primary source the insulator under high electrical stress in vacuum."

From Introduction: "An analysis of eddy currents in a compressor blade, the geometry of which has been limited to that of a flat plate for simplicity, is presented."

Report presenting an investigation to determine the damping-in-roll characteristics of a 42.7 degree sweptback wing using a linearly twisted wing to represent a rolling wing. Results regarding the effect of the airfoil contour, damping-in-roll coefficient, wing-tip helix angle, and theoretical results are provided.

Results of tests to determine the aerodynamic forces and moments on bodies of revolution at angles of attack from 0 degrees to 25 degrees are presented and compared with theory. Cones and ogives of fineness ratios 3 to 7 and two blunt-nosed body shapes with fineness ratios 3 and 5 were tested at Mach numbers from 2.75 to 5.00. Reynolds numbers were from 0.5 million to 6.4 million, depending on Mach number and body fineness ratio.

Report presenting a study of the supersonic longitudinal stability and control characteristics of a canard missile configuration using flight tests and wind-tunnel tests at a range of Mach numbers and Reynolds numbers. Good correlation was noted for the two techniques for slopes of lift and moment coefficients against angle of attack and for aerodynamic-center location.

Report presenting an investigation utilizing the transonic-bump technique through a range of Mach numbers in the high-speed 7- by 10-foot tunnel to determine the lateral control characteristics of retractable spoiler and plug-type spoiler-slot ailerons. The wing had a sweepback of 60 degrees at the quarter-chord line, an aspect ratio of 2, a taper ratio of 0.6, and an NACA 65A006 airfoil section parallel to the free stream. The plug-type spoiler-slot aileron was found to be more effective in producing roll than the retractable spoiler aileron through the entire range of values tested.

Report presenting the results of nine experimental flutter tests involving two flat-plate models and two rib and spar models of NACA 0012 airfoil sections in order to give a comparison of the flutter characteristics of wings with M and W type plan forms. The W plan form generally gave higher flutter speeds than the M plan forms.

Report presenting tests using the NACA wing-flow method at a range of Mach numbers to determine the aerodynamic characteristics of four triangular-wing-fuselage models. Measurements of the normal force, chord force, and pitching moment for various angles of attack. Two models had wings of aspect ratio 2.31, one with an NACA 65-009 airfoil section and one with a 9-percent-thick biconvex section, and two with wings of aspect ratio 4, one with an NACA 65-006 airfoil and one with a 6-percent-thick double-wedge airfoil.

The following report is the fourth in a series of reports on rare and uncommon elements prepared by the Geological Survey. This report covers columbius and tantalus, two chemical elements belonging to the fifth group of the periodic table and quinquevalent in most of their compounds.

Abstract: Procedures are presented in detail of two methods for the determination of very small percentages or uranium (down to 0.0025). The methods are applicable to a wide variety of materials. Notes on the methods and confirmatory experiments are also given.

Abstract: An ionization chamber to monitor air for beta activity is described. Operating curves are given, as well as results of shock and vibration tests. Recommendation for improved design are included.

Abstract: "The Midi Mist (U12n.02) event produced rock spalling along bedding, joint, and fault planes in the U12n.02 and U12n.03 drifts. The spalling in the U12n.02 drift started at about construction station 12 + 75 and was continuous toward the W.P. Most of the spalling in the U12n.03 drift occurred between C.S. 0 + 00 and 7 + 00."

This report for the month of July, 1949 discusses progress regarding work on the carbonate process and the recovery of uranium and vanadium from carbonate liquors.

From abstract: "The report describes the complete structure of barium hydrogen phosphate, Ba HPO4, as determined by means of x-ray diffraction. The crystal is orthorhombic, with cell dimensions given by a=5.71 A b=7.05 A c=4.61 A. The calculated density is 4.15gm/cm[^]3 for two molecules in the unit cell. The space group is C[subscript]2v[superscript]7-pmn. The barium, phosphorus, and two sets of oxygen lie in the plane of symmetry. The third set of oxygens are in general positions. Parameters for these atoms have been found, and interatomic distances calculated. The positions of the hydrogens are indicated by the characteristics O-H-O distance (2.58A) between two oxygens."

The pressure and temperature cycles developed during the bomb reduction of uranium tetrafluoride by calcium have been determined. Data for the 250, 500, and 1000 gram scale reductions are given, and the apparatus used is described.

Measurements have been at the Pajarito remote control laboratory to determine the effect of change of shape on system reactivity for oralloy cylinders. Systems tested include cylindrical configurations with various height-to-diameter ratios ranging from slabs to rods. Each system reactivity is referred to that of a sphere in the same tamper. Reactivity tests were made on bare (untamped) Oy configurations, as well as on systems In tuballoy tampers 1.12,1.87,and 8.0 thick. The amount of reactivity change associated with a particular cylinder height-to-diameter ratio is feud to be a function of tamper thickness, and is greatest for very thin tampers.

Report documenting the ongoing research and developments of the Oak Ridge National Laboratory's Homogeneous Reactor Project.

Report presents the results of a wind-tunnel investigation of the effect of wing-fuselage interference on lateral-stability characteristics made in the NACA 7 by 10-foot wind tunnel on four fuselages and two fins, representing high-wing, low-wing, and midwing monoplanes. The fuselages are of circular and elliptical cross section. The wings have rounded tips and, in plan form, one is rectangular and the three are tapered 3:1 with various amounts of sweep. The rate of change in the coefficients of rolling moment, yawing moment, and lateral force with angle of yaw is given in a form to show the increment caused by wing-fuselage interference for the model with no fin and the effect of wing-fuselage interference on fin effectiveness. Results for the fuselage-fin combination and the wing tested alone are also given.

From Summary: "A simple method is presented for estimating lift, pitching-moment, and hinge-moment characteristics of all-movable wings in the presence of a body as well as the characteristics of wing-body combinations employing such wings. In general, good agreement between the method and experiment was obtained for the lift and pitching moment of the entire wing-body combination and for the lift of the wing in the presence of the body. The method is valid for moderate angles of attack, wing deflection angles, and width of gap between wing and body."

Revision of genus Zapus based upon a study of more than 900 specimens, including nomenclature and skull and teeth figures.

Let F be the flux of radiation going from a sample of radius R2 to a counter of radius B1 then the emitted intensity of radiation per unit solid angle. Then the flux between two elements of area do1 and do2 will be given by [equation] since [equation] and [equation]. Calculations and equations follow.