41 Matching Results

Search Results

Advanced search parameters have been applied.

Tabulated Pressure Coefficients and Aerodynamic Characteristics Measured on the Wing of the Bell X-1 Airplane in an Unaccelerated Stall and in Pull-Ups at Mach Numbers of 0.74, 0.75, 0.94, and 0.97

Description: "Tabulated pressure coefficients and aerodynamic characteristics are presented for six spanwise stations on the left wing of the Bell X-1 research airplane. The data were obtained in an unaccelerated stall and in pull-ups at Mach numbers of 0.74, 0.75, 0.94, and 0.97" (p. 1).
Date: June 19, 1951
Creator: Smith, Lawrence A.
Partner: UNT Libraries Government Documents Department

Distributed Energy Resources, Power Quality and Reliability - Background

Description: Power quality [PQ] and power reliability [PR] gained importance in the industrialized world as the pace of installation of sensitive appliances and other electrical loads by utility customers accelerated, beginning in the mid 1980s. Utility-grid-connected customers rapidly discovered that this equipment was increasingly sensitive to various abnormalities in the electricity supply.
Date: January 31, 2002
Creator: Schienbein, Lawrence A. & DeSteese, John G.
Partner: UNT Libraries Government Documents Department

Electrical Generation for More-Electric Aircraft Using Solid Oxide Fuel Cells

Description: This report examines the potential for Solid-Oxide Fuel Cells (SOFC) to provide electrical generation on-board commercial aircraft. Unlike a turbine-based auxiliary power unit (APU) a solid oxide fuel cell power unit (SOFCPU) would be more efficient than using the main engine generators to generate electricity and would operate continuously during flight. The focus of this study is on more-electric aircraft which minimize bleed air extraction from the engines and instead use electrical power obtained from generators driven by the main engines to satisfy all major loads. The increased electrical generation increases the potential fuel savings obtainable through more efficient electrical generation using a SOFCPU. However, the weight added to the aircraft by the SOFCPU impacts the main engine fuel consumption which reduces the potential fuel savings. To investigate these relationships the Boeing 787­8 was used as a case study. The potential performance of the SOFCPU was determined by coupling flowsheet modeling using ChemCAD software with a stack performance algorithm. For a given stack operating condition (cell voltage, anode utilization, stack pressure, target cell exit temperature), ChemCAD software was used to determine the cathode air rate to provide stack thermal balance, the heat exchanger duties, the gross power output for a given fuel rate, the parasitic power for the anode recycle blower and net power obtained from (or required by) the compressor/expander. The SOFC is based on the Gen4 Delphi planar SOFC with assumed modifications to tailor it to this application. The size of the stack needed to satisfy the specified condition was assessed using an empirically-based algorithm. The algorithm predicts stack power density based on the pressure, inlet temperature, cell voltage and anode and cathode inlet flows and compositions. The algorithm was developed by enhancing a model for a well-established material set operating at atmospheric pressure to reflect the effect ...
Date: April 1, 2012
Creator: Whyatt, Greg A. & Chick, Lawrence A.
Partner: UNT Libraries Government Documents Department

Measurements of the pressure distribution on the horizontal-tail surface of a typical propeller-driven pursuit airplane in flight III: tail loads in abrupt pull-up push-down maneuvers

Description: Results regarding the total horizontal-tail load and the root bending-moment increments calculated by use of existing rational procedures compared with the experimental values obtained in pull-up push-down maneuvers on a propeller-driven pursuit-type airplane for six combinations of power, indicated airspeed, and pressure altitude.
Date: February 1948
Creator: Sadoff, Melvin & Clousing, Lawrence A.
Partner: UNT Libraries Government Documents Department

Measurements of the pressure distribution on the horizontal tail surface of a typical propeller-driven pursuit airplane in flight II: the effect of angle of sideslip and propeller operation

Description: Report presenting measurements in sideslipping flight of the pressure distribution over the horizontal tail surface of a tractor-propeller-driven pursuit airplane to determine the effects of angle of sideslip and propeller operation on the tail-load distribution. Results regarding the reduction of data, effect of sideslip and power on tail loads, effect of sideslip and power on tail moments, and a comparison of the calculated loading with experimental results.
Date: May 1947
Creator: Sadoff, Melvin & Clousing, Lawrence A.
Partner: UNT Libraries Government Documents Department

Packaging and shipment of irradiated spent fuel. Final report

Description: Irradiated spent fuel rods, rod sections, and other loose fuel were retrieved from various storage locations at the Battelle hot cells, packaged in stainless steel tubes, and inserted in a new basket assembly in preparation for shipment to EG&G Idaho. Few assemblies Connecticut Yankee S004 and Turkey Point 817 were also retrieved and prepared for shipment. All three fuel assemblies were loaded in shipping cask TN8-L and shipped to EG&G Idaho for storage.
Date: October 1, 1988
Creator: Kohli, R. & Lawrence, A.
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

The Radio and Optical Luminosity Evolution of Quasars II - The SDSS Sample

Description: We determine the radio and optical luminosity evolutions and the true distribution of the radio loudness parameter R, defined as the ratio of the radio to optical luminosity, for a set of more than 5000 quasars combining SDSS optical and FIRST radio data. We apply the method of Efron and Petrosian to access the intrinsic distribution parameters, taking into account the truncations and correlations inherent in the data. We find that the population exhibits strong positive evolution with redshift in both wavebands, with somewhat greater radio evolution than optical. With the luminosity evolutions accounted for, we determine the density evolutions and local radio and optical luminosity functions. The intrinsic distribution of the radio loudness parameter R is found to be quite different than the observed one, and is smooth with no evidence of a bi-modality in radio loudness. The results we find are in general agreement with the previous analysis of Singal et al., 2011 which used POSS-I optical and FIRST radio data.
Date: December 28, 2012
Creator: Singal, J.; Petrosian, V.; Stawarz, L. & Lawrence, A.
Partner: UNT Libraries Government Documents Department

Technology Development: Wireless Sensors and Controls BT0201 Review of Energy Scavenging Schemes and Recommended Order of Investigation

Description: This report reviews the characteristics of four candidate concepts that extract and convert ambient energy to provide electrical power for wireless sensors.
Date: September 1, 2004
Creator: DeSteese, John G.; Olsen, Larry C. & Schienbein, Lawrence A.
Partner: UNT Libraries Government Documents Department

Looking for Darwin's footprints in the microbial world

Description: As we observe the 200th anniversary of Charles Darwin's birthday, microbiologists interested in the application of Darwin's ideas to the microscopic world have a lot to celebrate: an emerging picture of the (mostly microbial) Tree of Life at ever-increasing resolution, an understanding of horizontal gene transfer as a driving force in the evolution of microbes, and thousands of complete genome sequences to help formulate and refine our theories. At the same time, quantitative models of the microevolutionary processes shaping microbial populations remain just out of reach, a point that is perhaps most dramatically illustrated by the lack of consensus on how (or even whether) to define bacterial species. We summarize progress and prospects in bacterial population genetics, with an emphasis on detecting the footprint of positive Darwinian selection in microbial genomes.
Date: March 30, 2009
Creator: Shapiro, B. Jesse; David, Lawrence A.; Friedman, Jonathan & Alm, Eric J.
Partner: UNT Libraries Government Documents Department

Electric Power From Ambient Energy Sources

Description: This report summarizes research on opportunities to produce electric power from ambient sources as an alternative to using portable battery packs or hydrocarbon-fueled systems in remote areas. The work was an activity in the Advanced Concepts Project conducted by Pacific Northwest National Laboratory (PNNL) for the Office of Research and Development in the U.S. Department of Energy Office of Nonproliferation and National Security.
Date: October 3, 2000
Creator: DeSteese, John G.; Hammerstrom, Donald J. & Schienbein, Lawrence A.
Partner: UNT Libraries Government Documents Department

On the Radio and Optical Luminosity Evolution of Quasars

Description: We calculate simultaneously the radio and optical luminosity evolutions of quasars, and the distribution in radio loudness R defined as the ratio of radio and optical luminosities, using a flux limited data set containing 636 quasars with radio and optical fluxes from White et al. We first note that when dealing with multivariate data it is imperative to first determine the true correlations among the variables, not those introduced by the observational selection effects, before obtaining the individual distributions of the variables. We use the methods developed by Efron and Petrosian which are designed to obtain unbiased correlations, distributions, and evolution with redshift from a data set truncated due to observational biases. It is found that as expected the population of quasars exhibits strong positive correlation between the radio and optical luminosities and that this correlation deviates from a simple linear relation in a way indicating that more luminous quasars are more radio loud. We also find that there is a strong luminosity evolution with redshift in both wavebands, with significantly higher radio than optical evolution. We conclude that the luminosity evolution obtained by arbitrarily separating the sources into radio loud (R > 10) and radio quiet (R < 10) populations introduces significant biases that skew the result considerably. We also construct the local radio and optical luminosity functions and the density evolution. Finally, we consider the distribution of the radio loudness parameter R obtained from careful treatment of the selection effects and luminosity evolutions with that obtained from the raw data without such considerations. We find a significant difference between the two distributions and no clear sign of bi-modality in the true distribution. Our results indicate therefore, somewhat surprisingly, that there is no critical switch in the efficiency of the production of disk outflows/jets between very radio quiet and ...
Date: May 20, 2011
Creator: Singal, J.; Petrosian, V.; Lawrence, A. & Stawarz, L.
Partner: UNT Libraries Government Documents Department

Sources of the Radio Background Considered

Description: We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.
Date: August 22, 2011
Creator: Singal, J.; Stawarz, L.; Lawrence, A. & Petrosian, V.
Partner: UNT Libraries Government Documents Department

Distribution of Nitrate in Ground Water Redlands, California

Description: Report and geographical survey. This report examines the distribution of nitrates in the Redland area's ground water and concludes that this distribution depends primarily upon depth below the water table and areal location. Includes several maps and figures.
Date: March 1977
Creator: Eccles, Lawrence A. & Bradford, Wesley L.
Partner: UNT Libraries Government Documents Department

Misaligned Disks as Obscurers in Active Galaxies

Description: We review critically the evidence concerning the fraction of Active Galactic Nuclei (AGN) which appear as Type 2 AGN, carefully distinguishing strict Type 2 AGN from both more lightly reddened Type 1 AGN, and from low excitation narrow line AGN, which may represent a different mode of activity. Low excitation AGN occur predominantly at low luminosities; after removing these, true Type 2 AGN represent 58{-+}5% of all AGN, and lightly reddened Type 1 AGN a further {approx}15%. Radio, IR, and volume-limited samples all agree in showing no change of Type 2 fraction with luminosity. X-ray samples do show a change with luminosity; we discuss possible reasons for this discrepancy. We test a very simple picture which produces this Type 2 fraction with minimal assumptions. In this picture, infall from large scales occurs in random directions, but must eventually align with the inner accretion flow, producing a severely warped disk on parsec scales. If the re-alignment is dominated by tilt, with minimal twist, a wide range of covering factors is predicted in individual objects, but with an expected mean fraction of Type 2 AGN of exactly 50%. This 'tilted disc' picture predicts reasonable alignment of observed nuclear structures on average, but with distinct misalignments in individual cases. Initial case studies of the few well resolved objects show that such misalignments are indeed present.
Date: June 2, 2010
Creator: Lawrence, A.; Elvis, M. & /Edinburgh U., Inst. Astron. /Harvard-Smithsonian Ctr. Astrophys.
Partner: UNT Libraries Government Documents Department

Measurements in flight of the pressure distribution on the right wing of a P-39N-1 airplane at several values of Mach number

Description: Report presenting pressure-distribution measurements made on the right wing of a P-39N-1 airplane at values of Mach number up to 0.80. A considerable portion of the lift was carried by components of the airplane other than the wings, and the proportion carried by the wing varies considerably with Mach number. Results regarding the variation of wing loads and moments with Mach number, internal wing pressure, and airplane lift-curve slope are provided.
Date: April 1945
Creator: Clousing, Lawrence A.; Turner, William N. & Rolls, L. Stewart
Partner: UNT Libraries Government Documents Department

Measurements of the pressure distribution on the horizontal-tail surface of a typical propeller-driven pursuit airplane in flight I: effects of compressibility in steady straight and accelerated flight

Description: Report presenting pressure-distribution measurements made in steady straight and accelerated flight over a horizontal tail surface of a typical pursuit airplane. Results regarding the variation of horizontal-tail loads with Mach number, variation of root bending moments and fuselage torsional moments with Mach number, and variation of section loads with Mach number are provided.
Date: July 1947
Creator: Sadoff, Melvin; Turner, William N. & Clousing, Lawrence A.
Partner: UNT Libraries Government Documents Department

Preliminary report on flight tests of an airplane having exhaust-heated wings

Description: Report presenting testing of an airplane in icing conditions to determine the effect of exhaust heat applied to the wings as a means of preventing ice formations. Other ice-prevention equipment, including an exhaust gas-heated pitot-static head, hot-air-heated windshield, and an inflatable de-icer were also tested.
Date: April 1941
Creator: Rodert, Lewis A.; McAvoy, William H. & Clousing, Lawrence A.
Partner: UNT Libraries Government Documents Department

Preliminary results of a flight investigation to determine the effect of negative flap deflection on high-speed longitudinal-control characteristics

Description: Report presenting flight testing on two propeller-driven airplanes with wings of NACA 66-series and NACA 230-series airfoil sections to determine the effect of deflecting the landing flaps upward on the high-speed longitudinal-control characteristics.
Date: December 16, 1947
Creator: White, Maurice D.; Sadoff, Melvin; Clousing, Lawrence A. & Cooper, George E.
Partner: UNT Libraries Government Documents Department

Measurements in flight of the pressure distribution on the right wing of a pursuit-type airplane at several values of Mach number

Description: Pressure-distribution measurements were made on the right wing of a pursuit-type airplane at values of Mach number up to 0.80. The results showed that a considerable portion of the lift was carried by components of the airplane other than the wings, and that the proportion of lift carried by the wings may vary considerably with Mach number, thus changing the bending moment at the wing root whether or not there is a shift in the lateral position of the center of pressure. It was also shown that the center of pressure does not necessarily move outward at high Mach numbers, even though the wing-thickness ratio decreases toward the wing tip. The wing pitching-moment coefficient increased sharply in a negative direction at a Mach lift-curve slope increased with Mach number up to values of above the critical value. Pressures inside the wing were small and negative.
Date: 1946
Creator: Clousing, Lawrence A.; Turner, William N. & Rolls, L. Stewart
Partner: UNT Libraries Government Documents Department

Compressibility effects on the longitudinal stability and control of a pursuit-type airplane as measured in flight

Description: Measurements of the longitudinal stability and control of a pursuit-type airplane were made in flight up to a Mach number of 0.78. The data are presented in the form of curves showing the variation, with center-of-gravity position, dynamic pressure, and Mach number, of the stick-fixed and stick-free stability, control, and balance of the airplane.
Date: 1946
Creator: Turner, William N.; Steffen, Paul J. & Clousing, Lawrence A.
Partner: UNT Libraries Government Documents Department

An analysis of longitudinal-control problems encountered in flight at transonic speeds with a jet-propelled airplane

Description: From Introduction: "This report presents an analysis based on flight and wind-tunnel test data directed toward the determination of the probable cause of the pitch-up. Wing pressure distribution and stability and control characteristics in the dive are also included."
Date: September 25, 1947
Creator: Brown, Harvey H.; Rolls, L. Stewart & Clousing, Lawrence A.
Partner: UNT Libraries Government Documents Department

Effects of taper ratio on the longitudinal characteristics at Mach numbers from 0.6 to 1.4 of a wing-body-tail combination having an unswept wing of aspect ratio 3

Description: Report presenting the results of a wind-tunnel investigation to determine the effects of a variation in wing taper ratio on the longitudinal characteristics of a wing-body combination at a variety of Mach numbers. The wings had an aspect ratio of 3, an unswept midchord line, and an NACA 64A003 profile. Results regarding the lift and pitching-moment characteristics and drag characteristics are provided.
Date: March 23, 1955
Creator: Summers, James L.; Treon, Stuart L. & Graham, Lawrence A.
Partner: UNT Libraries Government Documents Department