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Abnormal grain growth in M-252 and S-816 alloys

Description: Report discussing an experimental investigation was carried out on air- and vacuum-melted M-252 and S-816 alloys to find conditions of heating and hot-working which resulted in abnormal grain growth. The experiments were mainly limited to normal conditions of heating for hot-working and heat treatment and normal temperatures of solution treatment were used to allow grain growth after susceptibility to abnormal grain growth was developed by various experimental conditions. Results indicated that small reductions of essentially strain-free metal were the basic cause of such grain growth.
Date: November 1957
Creator: Decker, R F; Rush, A I; Dano, A G & Freeman, J W
Partner: UNT Libraries Government Documents Department

Abnormal grain growth in nickel-base heat-resistant alloys

Description: From Introduction: "The data included in this report for Nimonic 80A alloy, for instance, represent experiments carried out to help clarify a production problem of grain-size control in an alloy which has been extensively used. The general procedure of the investigation was to carry out controlled laboratory experiments on samples of bar stock to find conditions of heating and hot-working which resulted in abnormal grain growth."
Date: December 1957
Creator: Decker, R F; Rush, A I; Dano, A G & Freeman, A G
Partner: UNT Libraries Government Documents Department

Acceleration of high-pressure-ratio single-spool turbojet engine as determined from component performance characteristics I : effect of air bleed at compressor outlet

Description: An analytical investigation was made to determine from component performance characteristics the effect of air bleed at the compressor outlet on the acceleration characteristics of a typical high-pressure-ratio single-spool turbojet engine. Consideration of several operating lines on the compressor performance map with two turbine-inlet temperatures showed that for a minimum acceleration time the turbine-inlet temperature should be the maximum allowable, and the operating line on the compressor map should be as close to the surge region as possible throughout the speed range. Operation along such a line would require a continuously varying bleed area. A relatively simple two-step area bleed gives only a small increase in acceleration time over a corresponding variable-area bleed. For the modes of operation considered, over 84 percent of the total acceleration time was required to accelerate through the low-speed range ; therefore, better low-speed compressor performance (higher pressure ratios and efficiencies) would give a significant reduction in acceleration time.
Date: March 10, 1953
Creator: Rebeske, John J , Jr & Rohlik, Harold E
Partner: UNT Libraries Government Documents Department

Accelerations in fighter-airplane crashes

Description: From Introduction: "This report describes some measurements of these quantities obtained by crashing fighter aircraft under circumstances approximating those observed in service."
Date: November 4, 1957
Creator: Acker, Loren W; Black, Duglad O & Moser, Jacob C
Partner: UNT Libraries Government Documents Department

An accurate and rapid method for the design of supersonic nozzles

Description: From Introduction: "This report presents a computational procedure which provides for the rapid and accurate calculation of any streamline in a series of special flows. Detailed information is given on the boundary conditions and equations used for computing the characteristic nets and stream function."
Date: February 1955
Creator: Beckwith, Ivan E & Moore, John A
Partner: UNT Libraries Government Documents Department

Acoustic analysis of ram-jet buzz

Description: From Introduction: "The surging of a system containing a centrifugal- or axial-flow compressor (e.g., refs. 1 to 4) is an example of self-sustained oscillation. Inlets designed for supersonic jet engines also have been observed to induce oscillations (e.g., refs. 5 to 11) which are usually referred to as "buzz." The origin of buzz in ram-jet engines is the subject of the present report."
Date: November 1955
Creator: Mirels, Harold
Partner: UNT Libraries Government Documents Department

Acoustic radiation from two-dimensional rectangular cutouts in aerodynamic surfaces

Description: From Introduction: "The experiments in high-speed flow showed that an intense, high-frequency acoustic radiation is an essential feature of the problem. Consequently, a study of the acoustic field (involving schlieren observations and frequency and intensity measurements) was undertaken. This report presents the salient features of the study, which was mainly exploratory."
Date: August 1955
Creator: Krishnamurty, K
Partner: UNT Libraries Government Documents Department

Acoustic, thrust, and drag characteristics of several full-scale noise suppressors for turbojet engines

Description: From Introduction: " Considerable analytical and experimental research has been done to find means of reducing the noise levels of the turbojet transports. Noise levels can be decreased by engine redesign to reduce the jet-exit velocity (ref. 1), proper flight-climb techniques (ref. 2), and the use of noise-suppression exhaust nozzles (refs. 3 to 5). The present report is concerned with the last method."
Date: April 1958
Creator: Ciepluch, Carl C; North, Warren J; Coles, Willard D & Antl, Robert J
Partner: UNT Libraries Government Documents Department

Acoustical treatment for the NACA 8- by 6-foot supersonic propulsion wind tunnel

Description: From Introduction: "This report presents results of a research and engineering program performed during the first half of 1950 that resulted in an acoustical treatment for the 8- by 6-foot supersonic wind tunnel at the Lewis Flight Propulsion Laboratory."
Date: June 1955
Creator: Beranek, Leo L; Labate, Samuel & Ingard, Uno
Partner: UNT Libraries Government Documents Department

Acoustics of a nonhomogeneous moving medium.

Description: Report discussing theoretical basis of the acoustics of a moving nonhomogeneous medium. Experiments that illustrate or confirm some of the theoretical explanation or derivation of these acoustics are also included.
Date: February 1956
Creator: Blokhintsev, D I
Partner: UNT Libraries Government Documents Department

An active particle diffusion theory of flame quenching for laminar flames / Dorothy M. Simon and Frank E. Belles

Description: An equation for quenching distance based on the destruction of chain carriers by the surface is derived. The equation expresses the quenching distance in terms of the diffusion coefficients and partial pressures of the chain carriers and gas phase molecules, the efficiency of the surface as a chain breaker, the total pressure of the mixture, and a constant which depends on the geometry of the quenching surface. Quenching distances measured by flashback for propane-air flames are shown to be consistent with the mechanism. The derived equation is used with the lean inflammability limit and a rate constant calculated from burning velocity data to estimate quenching distances for propane-air (hydrocarbon lean) flames satisfactorily.
Date: March 4, 1952
Creator: Simon, Dorothy M & Belles, Frank E
Partner: UNT Libraries Government Documents Department