Technical Report Archive and Image Library (TRAIL) - 22,064 Matching Results

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Planing-surface tests at large Froude numbers - airfoil comparison

Description: The take-off capacity of a flying boat depends upon the design of the hull bottom ahead as well as aft of the step. Systematic tests - largely made by industry itself - had proved the benefit accruing from a well designed hull bottom long before theoretical insight into the flow phenomena involved had been obtained. The theoretical framing of the problem was beset with serious difficulties and, though restricted to the processes within range of the planing bottom ahead of the step, the solutions do not yet afford a comprehensive survey.
Date: February 1, 1938
Creator: Sambraus, A
Partner: UNT Libraries Government Documents Department

Planning Double-Tagging Experiments

Description: This report provides guidelines for planning experiments to determine how many fish should be double-tagged, the run-time of the experiment, and how the recovery data should be regrouped.
Date: June 1981
Creator: Wetherall, Jerry A. & Yong, Marian Y. Y.
Partner: UNT Libraries Government Documents Department

Plastic buckling of a rectangular plate under edge thrusts

Description: The fundamental equations for the plastic buckling of a rectangular plate under edge thrusts are developed on the basis of a new set of stress-strain relations for the behavior of a metal in the plastic range. These relations are derived for buckling from a state of uniform compression. The fundamental equation for the buckling of a simply compressed plate together with typical boundary conditions is then developed and the results are applied to calculating the buckling loads of a thin strip, a simply supported plate, and a cruciform section. Comparisons with the theories of Timoshenko and Ilyushin are made. Finally, an energy method is given which can be used for finding approximate values of the critical load.
Date: January 1, 1949
Creator: Handelman, G H & Prager, W
Partner: UNT Libraries Government Documents Department

Plastic deformation of aluminum single crystals at elevated temperatures

Description: This report describes the results of a comprehensive study of plastic deformation of aluminum single crystals over a wide range of temperatures. The results of constant-stress creep tests have been reported for the temperature range from 400 degrees to 900 degrees F. For these tests, a new capacitance-type extensometer was designed. This unit has a range of 0.30 inch over which the sensitivity is very nearly linear and can be varied from as low a sensitivity as is desired to a maximum of 20 microinches per millivolt with good stability. Experiments were carried out to investigate the effect of small amounts of prestraining, by two different methods, on the creep and tensile properties of these aluminum single crystals. From observations it has been concluded that plastic deformation takes place predominantly by slip which is accompanied by the mechanisms of kinking and polygonization.
Date: January 1, 1956
Creator: Johnson, R. D.; Young, A. P. & Schwope, A. D.
Partner: UNT Libraries Government Documents Department

Plastic Heat Exchangers : A State-of-the-Art Review

Description: Significant increases in energy utilization efficiency can be achieved through the recovery of low-temperature rejected heat. This energy conserving possibility provides incentive for the development of heat exchangers which could be employed in applications where conventional units cannot be used. Some unique anticorrosion and nonstick characteristics of plastics make this material very attractive for heat recovery where condensation, especially sulfuric acid, and fouling occur. Some of the unique characteristics of plastics led to the commercial success of DuPont's heat exchangers utilizing polytetrafluoroethylene (trade name Teflon) tubes. Attributes which were exploited in this application were the extreme chemical inertness of the material and its flexibility, which enabled utilization in odd-shaped spaces. The wide variety of polymeric materials available ensures chemical inertness for almost any application. Lower cost, compoundability with fillers to improve thermal/mechanical properties, and versatile fabrication methods are incentives for many uses. Also, since many plastics resist corrosion, they can be employed in lower temperature applications (< 436 K), where condensation can occur and metal units have been unable to function. It is clear that if application and design can be merged to produce a cost-effective alternate to present methods of handling low-temperature rejected heat, then there is significant incentive for plastic heat exchangers, to replace traditional metallic heat exchangers or to be used in services where metals are totally unsuited.
Date: July 1979
Creator: Miller, David; Holtz, Robert E.; Koopman, R. Nelson; Marciniak, Thomas J. & MacFarlane, Donald R.
Partner: UNT Libraries Government Documents Department

Plastic Heat Exchangers for Waste Heat Recovery

Description: Metallic corrosion is one of the major impediments to using the large amounts of heat available in flue and exhaust gases. Our approach is to develop plastic coatings to eliminate this corrosion problem and make this waste heat available economically. The advantages of plastics and their limitations in this application are discussed. Laboratory testing in an acid-condensing environment has been performed on numerous plastics and has identified several plastics with good potential as corrosion barriers. Polyphenylene sulfide, in particular, has resisted sulfuric acid attack for over 5000 hours and can be used at temperatures up to 300 C.
Date: September 1983
Creator: Roach, P. D. & Holtz, Robert E.
Partner: UNT Libraries Government Documents Department

Plastic Magnesia

Description: Report issued by the Bureau of Mines over the production methods and uses of plastic magnesia. Methods, properties, and uses of plastic magnesia are discussed. This report includes tables, illustrations, and photographs.
Date: 1925
Creator: Ralston, Oliver C. & Pike, Robert D.
Partner: UNT Libraries Government Documents Department

Plastic stress-strain relations for 75S-T6 aluminum alloy subjected to biaxial tensile stresses

Description: In this investigation, the material tested was a 75S-T6 aluminum alloy and the stresses were essentially biaxial and tensile. The biaxial tensile stresses were produced in a specially designed testing machine by subjecting a thin-walled tubular specimen to axial tension and internal pressure. Plastic stress-strain relations for various biaxial stress conditions were obtained using a clip-type SR-4 strain gage. Three types of tests were made: Constant-stress-ratio tests, variable-stress-ratio tests, and special tests. The constant-stress-ratio test results gave control data and showed the influence of biaxial stresses on the yield, fracture, and ultimate strength of the material. By means of the variable-stress-ratio tests, it is possible to determine whether there is any significant difference between the flow and deformation type of theory. Finally, special tests were conducted to check specific assumptions made in the theories of plastic flow. The constant-stress-ratio tests show that the deformation theory based on the octahedral, effective; or significant stress-strain relations is in approximate agreement with the test results. The variable-stress-ratio tests show that both the deformation and flow theory are in equally good agreement with the test results.
Date: August 1, 1951
Creator: Marin, Joseph; Ulrich, B H & Hughes, W P
Partner: UNT Libraries Government Documents Department

Plastics as structural materials for aircraft

Description: The purpose here is to consider the mechanical characteristics of reinforced phenol-formaldehyde resin as related to its use as structural material for aircraft. Data and graphs that have appeared in the literature are reproduced to illustrate the comparative behavior of plastics and materials commonly used in aircraft construction. Materials are characterized as to density, static strength, modulus of elasticity, resistance to long-time loading, strength under repeated impact, energy absorption, corrosion resistance, and ease of fabrication.
Date: December 1, 1937
Creator: Kline, G M
Partner: UNT Libraries Government Documents Department

Plate compressive strength of FS-1H magnesium-alloy sheet and a maximum-strength formula for magnesium-alloy and aluminum-alloy formed sections

Description: From Summary: "The plate compressive strength of FS-1h magnesium-alloy sheet was determined from local-instability tests of formed Z-section columns. The critical compressive stress was found to correlate well with the compressive stress-strain curve for the material. The curves of average stress at maximum load plotted against calculated elastic critical strain resulted in a family of curves similar to previous results for aluminum-alloy sheet."
Date: October 1948
Creator: Gallaher, George L.
Partner: UNT Libraries Government Documents Department

Plates To Accompany Final Report Of Geological, Geophysical, Chemical, And Hydrological Investigations Of The Sand Springs Range, Fairview Valley, And Fourmile Flat, Churchill County, Nevada

Description: The following documents are aseries of plates to accompany the final report of "Geological, Geophysical, Chemical, and Hydrological Investigations of the Sand Springs Range, Fairview Valley, and Fourmile Flat, Churchill County, Nevada".
Date: 1965
Creator: Nevada. Bureau of Mines.
Partner: UNT Libraries Government Documents Department

Plating Thickness Tester

Description: An electromagnetic eddy current instrument is described that is capable of measuring copper and nickel plating 1 to 8 mils thick plated on bismuth mandrils of various sizes and shapes.
Date: November 15, 1957
Creator: Fitch, C. E., Jr.
Partner: UNT Libraries Government Documents Department