UNT Libraries Government Documents Department - 1,000 Matching Results

Search Results

N-17, A Delayed Neutron Emitter

Description: The decay scheme of a 4.2 second neutron emitter has been investigated in detail. Chemical and physical evidence shows that it is N{sup 17}, which emits beta rays to a broad excited state of O{sup 17}, which then breaks up into a neutron plus O{sup 16}. The energy spectrum of the neutrons is determined by measuring the energies of the O{sup 16} recoils in a proportional counter. The neutrons have a most probable energy of 0.9 Mev, a 'half width' of less than .5 Mev, and an upper limit of about 2 Mev. {beta}-recoil coincidences are observed, as predicted by the Bohr-Wheeler theory, and the {beta}-ray energy is measured by absorption. The beta rays in coincidence with neutrons have an upper limit of 3.7 {+-} 0.2 Mev. Beta-rays directly to the ground stat of O{sup 17} are not observed because of high background effects, but should have an energy of 8.7 Mev. Some evidence is presented to show that energy is conserved in the {beta}-n transition through the broad excited state in O{sup 17}.
Date: November 5, 1948
Creator: Alvarez, L. W.

234-5 Project specification letter 234-41, 235-41 (Supplement D), Chemical Development Laboratory

Description: This letter itemizes the miscellaneous equipment and supplies not previously specified which should be ordered to equip the 234-5 Chemical Development Laboratory. Equipment currently carried in store stock is not included in this list. The vendor is given only to identify the item or as a suggested source of supply.
Date: October 22, 1948
Creator: Work, J.B.

Accuracy of airspeed measurements and flight calibration procedures

Description: From Summary: "The sources of error that may enter into the measurement of airspeed by pitot-static methods are reviewed in detail together with methods of flight calibration of airspeed installations. Special attention is given to the problem of accurate measurements of airspeed under conditions of high speed and maneuverability required of military airplanes." (author).
Date: 1948
Creator: Huston, Wilber B

Additional abstracts pertaining to seaplanes

Description: From Summary: "About 500 additional references pertaining to hydrodynamic design of seaplanes have been compiled, and the information is presented in the form of abstracts classified under six main headings:GENERAL INFORMATION, HYDROSTATICS, HYDRODYNAMICS, AERODYNAMICS, OPERATION, and RESEARCH. The compilation is an extension of NACA RM No. L6I13, entitled "Abstracts Pertaining to Seaplanes," by Jerold M. Bidwell and Douglas A. King. An author index and a subject index are included."
Date: March 9, 1948
Creator: Bidwell, J. M. & King, D. A.

Additional free-flight tests of the rolling effectiveness of several wing-spoiler arrangements at high subsonic, transonic, and supersonic speeds

Description: From Introduction: "The purpose of the present paper is to present results obtained recently relating to the characteristics of a full-span sharp-edge spoiler with an 0.02-chord projection above the wing surface at several chordwise positions and also to the relative effectiveness of the sharp-edge spoiler and a wedge-type spoiler located at the 80-percent-chord line."
Date: November 24, 1948
Creator: Strass, H Kurt

Aerodynamic characteristics at high speeds of a two-blade NACA 10-(3)(062)-045 propeller and of a two-blade NACA 10-(3)(08)-045 propeller

Description: From Introduction: "The aerodynamic characteristics of a series of 10-foot-diameter propellers are being investigated in the Langley 16-foot high-speed tunnel in a comprehensive propeller research program. Using high-critical-speed NACA 16-series airfoil sections (reference 1), these propellers are designed to have Betz minimum induced-energy loss loading (reference 2) for a blade angle of 45^o at the 0.7 radius, when used as a four-blade propeller operating at an advance ratio of approximately 2.1 The ultimate purpose of the program is to determine the influence upon propeller design factors and of compressiblity; the propeller tests reported herein form part of the investigation of the effects of blade-section thickness ratio."
Date: October 1, 1948
Creator: Solomon, William

Aerodynamic characteristics at subsonic and supersonic Mach numbers of a thin triangular wing of aspect ratio 2 II : maximum thickness at midchord

Description: The lift, drag, and pitching-moment characteristics of a triangular wing, having an aspect ratio of 2 and a symmetrical double-wedge profile of 5-percent-chord maximum thickness at midchord, have been evaluated from wind-tunnel tests at Mach numbers from 0.50 to 0.975 and from 1.09 to 1.49 and at Reynolds numbers ranging from 0.67 to 0.85 million. The lift, drag, and pitching-moment coefficients of the triangular wing with a leading-edge sweepback of approximately 63 degrees did not exhibit the irregular variations with Mach number at high subsonic and low supersonic Mach numbers that are characteristic of unswept wings. The lift-curve slope increased steadily with Mach number below unity and declined slowly beyond the Mach number of 1.13. A substantial rise in the minimum drag coefficient occurred between Mach numbers of 0.95 and 1.20 with an associated reduction in the maximum lift-drag ratio. The aerodynamic center shifted rearward toward the centroid of area of the wing with increasing Mach number below 0.975; whereas above 1.09 it coincided with the centroid.
Date: December 3, 1948
Creator: Walker, Harold J & Berggren, Robert E

Aerodynamic properties of slender wing-body combinations at subsonic, transonic, and supersonic speeds

Description: From Introduction: "In an incomprehensible medium, the mutual interference of a fuselage and wing of high-aspect ratio (to which lifting-line theory is applicable) has been treated by Lennertz, Wiselsberger, Pepper, and Multhopp in reference 1, 2, 3, and 4. It is the purpose of this note to treat the effect of on the aerodynamic loading of the mutual interference between a low-aspect-ratio pointed wing and a fuselage consisting of a slender body of revolution."
Date: July 1948
Creator: Spreiter, John R