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Pre-Cambrian Rocks of the Lake Superior Region: A Review of Newly Discovered Geologic Features, with a Revised Geologic Map

Description: From abstract: Detailed knowledge of the geology of the pre-Cambrian rocks of the Lake Superior region has been greatly augmented since the publication of Monograph 52 by the United States Geological Survey in 1911. The authors have attempted in the present report to assemble as much of this new information as possible, and to give the reader a birdseye view of the geology as seen in the light of all studies made there up to the present time. Detailed descriptions are not presented, and the emphasis is placed upon the major problems of correlation. A revised map of the region, with cross sections, accompanies the report, bringing up to date a knowledge of the areal geology of the region, which otherwise could be gained only by consulting some 150 maps contained in almost as many separate local reports, many of which are unpublished.
Date: 1935
Creator: Leith, C. K.; Lund, Richard Jacob & Leith, Andrew
Partner: UNT Libraries Government Documents Department

Precast Concrete Elements for Structures in Selected Theaters of Operations

Description: Partial abstract: "The current state of the art of design, fabrication, and erection techniques of various prefabricated elements for concrete structures are reviewed. Included are precast concrete highway bridges, logging bridges, railway bridges, piles, culverts, pipes, floating structures, and field fortifications. The structural properties, advantages, and disadvantages of various elements and systems are discussed."
Date: February 1978
Creator: McDonald, James E. & Liu, Tony C.
Partner: UNT Libraries Government Documents Department

Precautions for flight testing near the speed of sound

Description: From experience gained by NACA test pilots in flying at high subsonic Mach numbers and from interpretation of the data obtained, some general precautionary rules for test flying near sonic Mach numbers have been formulated. The reasons for these rules are discussed and observations are made with respect to the hazards arising from undesirable stability and control characteristics which have been noted in test flights of various airplanes. This paper, although written primarily for the attention of test pilots, contains general information of interest to those who are concerned with various phases of flight testing near sonic Mach numbers.
Date: November 5, 1947
Creator: Clousing, Lawrence A
Partner: UNT Libraries Government Documents Department

Prechamber compression-ignition engine performance

Description: Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.
Date: January 1, 1938
Creator: Moore, Charles S & Collins, John H , Jr
Partner: UNT Libraries Government Documents Department

Precipitation of Lead and Copper from Solution on Sponge Iron

Description: From abstract of Bulletin: "The results of the experiments described in this bulletin are largely a record of the behavior of sponge iron as precipitant of lead and copper under laboratory conditions comparable to those that would obtain in a commercial plant were it attempted to secure the maximum contact of surface between solution and precipitant."
Date: 1928
Creator: Oldright, G. L.; Keyes, H. E.; Miller, Virgil & Sloan, W. A.
Partner: UNT Libraries Government Documents Department

Precipitation-Runoff Modeling System: User's Manual

Description: From introduction: This documentation is designed to provide the user with the basic philosophy and structure of PRMS, instructions for application of established models designed as cataloged procedures, and instructions for interaction with the PRMS library to permit user additions or modifications of model components. The components and subroutines described in this document are those available at the time of publication. However, the library is dynamic and will be enhanced and updated through time. This manual will be updated to reflect major additions and changes through manual inserts or republications.
Date: 1983
Creator: Leavesley, G. H.; Lichty, R. W.; Troutman, B. M. & Saindon, L. G.
Partner: UNT Libraries Government Documents Department

Precision Measurement and Calibration: Electricity: Selected Papers on the Realization and Maintenance of the Fundamental Electrical Units and Related Topics

Description: Abstract: Selected publications of the National Bureau of Standards technical staff in the field of electricity were first compiled in 1962 as a volume of the NBS Precision Measurement and Calibration Series (Electricity and Electronics, Handbook 77, Volume I); this compilation was extended in 1968 by the compilation of an additional volume in the Precision Measurement and Calibration Series (Electricity-Low Frequency, NBS Special Publication 300, Volume 3). The present volume, a further extension of these earlier compilations of selected publications in the field of electricity, includes 66 more recent papers by NBS authors and 16 abstracts of closely related papers by authors from other organizations. In view of the expansion of measurement technologies used in electricity and electromagnetism it has been necessary to reduce the range of topics for the selection of papers in the new compilation. In this connection an emphasis has been placed upon the realization and maintenance of fundamental electrical units and the related scientific advances, particularly in quantum physics. However, in the interest of completeness, three appendices also provide up-to-date bibliographies of publications by NBS authors in different areas of electromagnetism. (This book is a sequel to NBS Handbook 77-Vol. 1(1961) and NBS SP 300-Vol. 3 (1968).
Date: October 1985
Creator: McCoubrey, Arthur O.
Partner: UNT Libraries Government Documents Department

A Preconditioned Conjugate Gradient Method for Solving a Class of Non-Symmetric Linear Systems

Description: This report describes a conjugate gradient preconditioning scheme for solving a certain system of equations which arises in the solution of a three dimensional partial differential equation. The problem involves solving systems of equations where the matrices are large, sparse, and non-symmetric.
Date: October 1981
Creator: Dongarra, J. J.; Leaf, G. K. & Minkoff, Michael
Partner: UNT Libraries Government Documents Department

Predicted Heat-Transfer Performance of an Evacuated Glass-Jacketed CPC Receiver : Countercurrent Flow Design

Description: The heat-transfer performance of an evacuated glass-jacketed CPC-receiver facility, free on one end and fixed onto the glass jacket at the other, was carried out using heat-transfer relationships and the best information available in the literature. Specifically, the collector examined was a 3x-CPC facility, 8 ft long, with an entrance aperture 4.5 in. wide covered with a single glass cover, and provided with an aluminum reflecting surface (rho = 0.88). To maximize heat retention, a selectively treated receiver surface, epsilon = 0.11, was used. The optical efficiency of this CPC collector facility was calculated to be eta₀ = 0.536.
Date: May 1976
Creator: Thodos, George
Partner: UNT Libraries Government Documents Department

The prediction of airfoil characteristics

Description: This report describes and develops methods by which the aerodynamic characteristics of an airfoil may be calculated with sufficient accuracy for use in airplane design. These methods for prediction are based on the present aerodynamic theory and on empirical formulas derived from data obtained in the N. A. C. A. variable density wind tunnel at a Reynolds number corresponding approximately to full scale. (author).
Date: January 1, 1930
Creator: Higgins, George J
Partner: UNT Libraries Government Documents Department

Prediction of downwash and dynamic pressure at the tail from free-flight measurements

Description: The present measurements form a continuation of earlier flight tests published in a previous report for predicting the downwash at the tail of an airplane. The method makes use of the tail itself as integrating contact surface to the extent that, beginning from the measurement of the self-alignment of the elevator, the mean downwash angle and dynamic pressure at the tail are determined. The instrumental accuracy is considerably improved if the elevator is completely separate from the controls during the tests, because the effect of friction on the self-alignment of the elevator is then reduced to a minimum and a finer elevator weight balance is rendered possible. The structural design of the push-rod uncoupling mechanism is also described.
Date: July 1, 1942
Creator: Eujen, E
Partner: UNT Libraries Government Documents Department

Prediction of flame velocities of hydrocarbon flames

Description: The laminar-flame-velocity data previously reported by the Lewis Laboratory are surveyed with respect to the correspondence between experimental flame velocities and values predicted by semitheoretical and empirical methods. The combustible mixture variables covered are hydrocarbon structure (56 hydrocarbons), equivalence ratio of fuel-air mixture, mole fraction of oxygen in the primary oxygen-nitrogen mixture (0.17 to 0.50), and initial mixture temperature (200 degrees to 615 degrees k). The semitheoretical method of prediction considered are based on three approximate theoretical equations for flame velocity: the Semenov equation, the Tanford-Pease equation, and the Manson equation.
Date: January 1, 1954
Creator: Dugger, Gordon L & Simon, Dorothy M
Partner: UNT Libraries Government Documents Department