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Results for “proximity effect”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Effects of ground proximity on a low aspect ratio propulsive wing/canard configuration

The effect of near proximity to the ground are investigated on a low aspect ratio propulsive wing/canard concept at STOL conditions. Data were obtained on a wing/body and wing/body/canard configuration at various heights above the ground, ranging from free air to approximately 1/4 of the mean aerodynamic chord (MAC) above the ground. The data presented and discussed include force and moment coefficients, surface pressure distributions, and downwash angles measured one MAC behind the wing. The test technique, model requirements, and special considerations required for testing these configurations are also discussed. Special model requirements included evenly distributed exit nozzle pressures along four separate nozzles of lengths of one and two feet with only one air supply to the model. Test techniques must recognize and deal with the ground boundary layer as well as the air supply pressure measurement and management.

Stewart, V. R.↗
NASA NTRS1974

Aerodynamic results of an abort separation effects test (IA8) conducted in the NASA/ARC 14-foot transonic wind tunnel on a model (6-OTS) of the Rockwell International launch configuration integrated vehicle

Experimental aerodynamic investigations were conducted on a 6-OTS 0.015-scale model. The Ames dual sting support separation rig was used to obtain grid-type data for tank-booster abort from orbiter (SSV). Freestream data were obtained for the orbiter to provide a baseline for evaluation of proximity effects. Data were obtained at Mach numbers from 0.32 to 1.1, and Reynolds number per foot varying from 2.1 million to 3.9 million. Data are not presented. Because of balance failure, a very substantial portion of the test was run with a dummy balance in the tank boosters configuration.

Campbell, J. H.↗
NASA NTRS1988

Sedimentological effects of tsunamis, with particular reference to impact-generated and volcanogenic waves

Impulse-generated waves (tsunamis) may be produced, at varying scales and global recurrence intervals (RI), by several processes. Meteorite-water impacts will produce tsunamis, and asteroid-scale impacts with associated mega-tsunamis may occur. A bolide-water impact would undoubtedly produce a major tsunami, whose sedimentological effects should be recognizable. Even a bolide-land impact might trigger major submarine landslides and thus tsunamis. In all posulated scenarios for the K/T boundary event, then, tsunamis are expected, and where to look for them must be determined, and how to distinguish deposits from different tsunamis. Also, because tsunamis decrease in height as they move away from their source, the proximal effects will differ by perhaps orders of magnitude from distal effects. Data on the characteristics of tsunamis at their origin are scarce. Some observations exist for tsunamis generated by thermonuclear explosions and for seismogenic tsunamis, and experimental work was conducted on impact-generated tsunamis. All tsunamis of interest have wave-lengths of 0(100) km and thus behave as shallow-water waves in all ocean depths. Typical wave periods are 0(10 to 100) minutes. The effect of these tsunamis can be estimated in the marine and coastal realm by calculating boundary shear stresses (expressed as U*, the shear velocity). An event layer at the K/T boundary in Texas occurs in mid-shelf muds. Only a large, long-period wave with a wave height of 0(50) m, is deemed sufficient to have produced this layer. Such wave heights imply a nearby volcanic explosion on the scale of Krakatau or larger, or a nearby submarine landslide also of great size, or a bolide-water impact in the ocean.

Bourgeois, Joanne↗
NASA NTRS1995

(abstract) All Epitaxial Edge-geometry SNS Devices with Doped PBCO and YBCO Normal Layers

We will present our results on tapered-edge-geometry SNS weak link fabricated from c-axis oriented base-, counterelectrode and normal layers using a variety of processing conditions. To date, we have employed a variety of different normal materials (Co-doped YBCO, Y-doped PBCO, Ca-doped PBCO). We have been examining the junction fabrication process in detail and we will present our methods. In particular, we have been examining both epitaxial and non-epitaxial milling mask overlayers and we will present a comparison of both methods. These devices behave similar to the expectations of the resisively shunted junction model and conventional SNS proximity effect models but with some differences which will be discussed. We will present the detailed systematics of our junctions including device parameters versus temperature, rf and dc magnetic response for the various processing conditions.

epitaxial doped PBCO YBCO junction fabrication mil↗
NASA NTRS1975

Aerodynamic results of a separation effects test conducted in the AEDC 40 by 40 inch tunnel A facility on the Rockwell International launch configuration 3 (model-OTS) integrated vehicle (IA13), volume 1

Experimental aerodynamic investigations were conducted from July 5 through July 17, 1973, on a 0.01 scale model. The AEDC captive trajectory system was utilized in conjunction with the tunnel primary sector to obtain grid-type data for external tank abort from the orbiter, and for nominal separation of one solid rocket booster from the orbiter-tank combination. Booster separation was investigated with and without separation motors plume simulation. The plumes were generated by eight M sub j = 2.15 nozzles using a 1500 psia cold air supply. Free stream data were obtained for all models (orbiter, tank, orbiter-tank, and right-hand booster) to provide baselines for evaluation of proximity effects.

Campbell, J. H., II↗
NASA NTRS1968

One hundred angstrom niobium wire

Composite of fine niobium wires in copper is used to study the size and proximity effects of a superconductor in a normal matrix. The niobium rod was drawn to a 100 angstrom diameter wire on a copper tubing.

Cline, H. E.↗
NASA NTRS1971

Mass spectrometry in structural and stereochemical problems. CXCIX.

Electron-impact induced fragmentations of o-, m-, and p-hydroxyalkylphenones and their trimethylsilyl (TMS) ethers are studied by means of high-resolution mass spectrometry, metastable defocusing, and deuterium labeling of the TMS ether derivatives. A markedly increased methyl radical loss from the o-TMS ether is attributed to a proximity effect. Minor fragmentation was observed with m- and p-isomers. Significantly intense doubly-charged ions were formed from ketonic cleavage and by the loss of a TMS methyl radical. The sequence of fragmentation was found to depend on the size of the alkyl group attached to the ketone carbonyl.

Smith, G. G.↗
NASA NTRS1975

Superconducting quantum-interference devices

Published document discusses devices which are based on weak-link Josephson elements that join superconductors. Links can take numerous forms, and circuitry utilizing links can perform many varied functions with unprecedented sensitivity. Theoretical review of Josephson's junctions include tunneling junctions, point contact devices, microbridges, and proximity-effect devices.

Peters, P. N.↗
NASA NTRS1975

Rigid format alter packets for the analysis of electromagnetic field problems

The computer program NASTRAN is used to solve electromagnetic field problems. The diffusion equation and the boundary conditions valid for problems of these kinds together with a replacing potential energy function are given. The extent to which an analogy with finite element displacement and temperature approaches holds is indicated. The outputting of complex quantities is made possible after adjustment of standard rigid format 1 input data blocks to module SDR2. The applications made involve the study of the proximity effect in a system of three parallel conductors and the analysis of the magnetic field in the vicinity of the points of contact in circuit breakers.

Spreeuw, E.↗
NASA NTRS1975

Advances in superconducting quantum electronic microcircuit fabrication

Standard microelectronic fabrication techniques have been utilized to produce batch quantities of superconducting quantum electronic devices and circuits. The overall goal is a fabrication technology yielding circuits that are rugged and stable and capable of being fabricated controllably and reproducibly in sizeable quantities. Our progress toward this goal is presented, with primary emphasis on the most recent work, which includes the use of electron-beam lithography and techniques of hybrid microelectronics. Several prototype microcircuits have been successfully fabricated. These microcircuits are formed in a thin-film parent material consisting of layers of superconducting and normal metals, and use proximity-effect structures as the active circuit elements.

Kirschman, R. K.↗
NASA NTRS1976

Results of an aerodynamic investigation of a space shuttle orbiter/747 carrier flight test configuration to determine separation characteristics utilizing 0.0125-scale models (48-0/AX1318I-1) in the LTV 4 x 4 foot high speed wind tunnel (CA26), volume 1

Results of tests conducted on a 0.0125-scale model of the Space Shuttle Orbiter and a 0.0125-scale model of the 747 CAM configuration in a 4 x 4-foot High Speed Wind Tunnel were presented. Force and moment data were obtained for each vehicle separately at a Mach number of 0.6 and for each vehicle in proximity to the other at Mach numbers of 0.3, 0.5, 0.6 and 0.7. The proximity effects of each vehicle on the other at separation distances (from the mated configuration) ranging from 1.5 feet to 75 feet were presented; 747 Carrier angles of attack from 0 deg to 6 deg and angles of sideslip of 0 deg and -5 deg were tested. Model variables included orbiter elevon, aileron and body flap deflections, orbiter tailcone on and off, and 747 stabilizer and rudder deflections.

Gillins, R. L.↗
NASA NTRS1977

Measurement of post-separated flowfields on airfoils

A small combination pitch-yaw probe designed to facilitate measurement of post-separated flow fields on airfoils is described, along with its calibration. A five-tube probe is found 'ideally suited' to separated-flow measurements because of the pitch and yaw angle information provided in addition to static and total pressures. Wall proximity effects (in a low-speed tunnel) are described. Procedures for measurements in flows with small inclinations in pitch and yaw, for large flow angles, and for scanning flows with large inclinations are indicated.

Seetharam, H. C.↗
NASA NTRS1980

Wall proximity corrections for hot-wire readings in turbulent flows

This note describes some details of recent (successful) attempts of wall proximity corrections for hot-wire measurements performed in a three-dimensional incompressible turbulent boundary layer. A simple and quite satisfactory method of estimating wall proximity effects on hot-wire readings is suggested.

Hebbar, K. S.↗
NASA NTRS1987

Low speed wind tunnel test of a propulsive wing/canard concept in the STOL configuration. Volume 1: Test description and discussion of results

A propulsive wing/canard model was tested at STOL operating conditions in the NASA Langley Research Center 4 x 7 meter wind tunnel. Longitudinal and lateral/directional aerodynamic characteristics were measured for various flap deflections, angles of attack and sideslip, and blowing coefficients. Testing was conducted for several model heights to determine ground proximity effects on the aerodynamic characteristics. Flow field surveys of local flow angles and velocities were performed behind both the canard and the wing. This is volume 1 of a 2 volume report. The model, instrumentation, and test procedures are described. An analysis of the data is included.

Stewart, V. R.↗
NASA NTRS1987

Low speed wind tunnel test of a propulsive wing/canard concept in the STOL configuration. Volume 2: Test data

A propulsive wind/canard model was tested at STOL operating conditions in the NASA Langley Research Center 4 x 7 meter wind tunnel. Longitudinal and lateral/directional aerodynamic characteristics were measured for various flap deflections, angles of attack and sideslip, and blowing coefficients. Testing was conducted for several model heights to determine ground proximity effects on the aerodynamic characteristics. Flow field surveys of local flow angles and velocities were performed behind both the canard and the wing. This is volume 2 of a 2 volume report. All of the test data in three appendices are presented. Appendix A presented tabulated six component force and moment data, Appendix B presents tabulated wing pressure coefficients, and Appendix C presents the flow field data.

Stewart, V. R.↗
NASA NTRS1988

Radial velocity studies and absolute parameters of contact binaries. I - AB Andromedae

New radial velocity curves have been obtained for the contact binary AB And, using the cross-correlation technique. A mass ratio of 0.479 is determined, which is revised to 0.491 when the velocities are corrected for proximity effects using a light curve model. These values differ by less than ten percent from the photometric mass ratio. An analysis of the symmetric B and V light curves reported by Rigterink in 1973 using the spectroscopic mass ratio yields a consistent set of light and velocity curve elements. These also produce a reasonably good fit to the infrared J and K light curves reported by Jameson and Akinci in 1979. Absolute elements are determined, and these indicate that both components have a main-sequence internal structure. These absolute parameters, together with the Galactic kinematics, suggest an age for the system similar to or greater than that of the Sun.

Hrivnak, Bruce J.↗