Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “B”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

On scaling the magnetic field strength in interstellar clouds Resolution of the 'B versus n dilemma'

Attention is given to the 'B versus n dilemma' associated with the near constancy of magnetic field strength based on H I Zeeman data over a range of gas densities. The problem is examined in terms of preferential mass flow along magnetic field lines resulting from the low thermal energy of these regions. Approximate relations have been found to scale the magnetic field strength in interstellar clouds. It is noted that the fiducial gas density for scaling the increasing magnetic field strength is 2-3 orders of magnitude above the average interstellar density often used to estimate B.

Fleck, R. C., Jr.↗
NASA NTRS1983

NASA B-57B severe storms flight program

The B-57B Severe Storms Flight Program gathers data to characterize atmosphere anomalies such as wind shear, turbulence, and microbursts at altitudes up to 1000 feet (300 meters). These data are used to enhance the knowledge of atmospheric processes, to improve aviation safety, to develop systems technology and piloting technique for avoiding hazards and to increase the understanding of the causes of related aircraft accidents. The NASA Dryden Flight Research Facility B-57B aircraft has participated in several severe storms data collection programs such as the Joint Airport Weather Studies (JAWS) located in Denver, Colorado area, Operation Rough Rider located in the Norman, Oklahoma area with the National Severe Storms Laboratory, and Mountain and desert turbulence in the Edwards Air Force Base, California area. Flight data are presented from flights which encountered the wind shear, turbulence and microburst anomalies. These flight results are discussed and some conclusions are made relating to these atmospheric anomalies.

Painter, W. D.↗
NASA NTRS1984

GP-B error modeling and analysis

The analysis and modeling for the Gravity Probe B (GP-B) experiment is reported. The finite-wordlength induced errors in Kalman filtering computation were refined. Errors in the crude result were corrected, improved derivation steps are taken, and better justifications are given. The errors associated with the suppression of the 1-noise were analyzed by rolling the spacecraft and then performing a derolling operation by computation.

Source record↗
NASA NTRS1984

NASA's B-57B Gust Gradient Program

The B-57B Gust Gradient Program is a joint effort of NASA Headquarters, Marshall Space Flight Center, Dryden Flight Research Facility, Langley Research Center, and Ames Research Center. The primary program goal is to measure spanwise variations of turbulent gusts across an airflow. To this end, the NASA B-57B aircraft was equipped with three component gust probes on each wing tip and on the nose. Early results of flights done in conjunction with the Joint Airport Weather Studies (JAWS) project are described.

Camp, D.↗
NASA NTRS1984

Ultraviolet and visible flare observations of EQ Pegasi B

EQ Peg AB (dM43+dM5.5e) was monitored in the visible at the Whipple Observatory and ultraviolet with IUE on September 2, 1981. In the visible spectrophotometry of EQ Peg B the H-beta emission strengthened by a factor of 2 relative to the nearby stellar continuum within a few minutes and decayed over an hour. This flare in EQ Peg B was coincident with the enhancement of ultraviolet emission lines of C IV 1550 A, He II 1640 A, and C II 1335 A in the combined light of EQ Peg AB. The ultraviolet fluxes during the flare can be interpreted as similar to those either in the thermal phases of large two-ribbon solor flares where radiative cooling balances thermal conduction or in gas cooling quickly from X-ray emitting temperatures. The appearance of the ultraviolet continuum at 1700-1900 A and ratio of H-alpha to H-beta fluxes during the flare are consistent with models producing these emissions in the chromosphere.

Baliunas, S. L.↗
NASA NTRS1984

SIR-B analysis of the Precambrian shield of Sudan and Egypt: Penetration studies and subsurface mapping

A shuttle imaging radar-B (SIR-B) study is proposed for the Precambrian shield in southeast Egypt and northeast Sudan in an area east of the Nile. The phenomenon of radar penetration of thin, dry eolian/alluvial cover is to be confirmed and quantified. The penetration phenomenon is to be used to map structural and lithologic features. Field work to be done in conjunction with image acquisition is discussed.

Dixon, T. H.↗
NASA NTRS1984

Evaluation of SIR-B data for identifying rainfall event occurrence and intensity

The utility of shuttle imaging radar-B (SIR-B) data for the detection and measurement of rainfall events is to be investigated. The investigation is described along with the approach for data acquisition, handling, and analysis. Anticipated results are also considered. The CROPCAST rainfall estimation technique is discussed.

Garofalo, D.↗
NASA NTRS1984

Geological, structural, and geomorphological analyses from SIR-B

A Shuttle Imaging Radar-B (SIR-B) study designed to develop a better understanding of the application of radar in geological studies is described. The specific objectives for deltaic environments include the examination of delta morphology and the intertidal zone, the surface expression of shallow bathymetry, the characterization of vegetation cover, and the water balance of the delta. In impact crater environments, the goals include the establishment of the radar characteristics of exposed craters and the application of this knowledge to test for the detectability of very poorly exposed craters.

Head, J. W., III↗
NASA NTRS1984

SIR-B cartography and stereo topographic mapping

The SIR-B mapping experiment which will evaluate the utility of SAR images taken singularly, in pairs, and in combination with other data sets for cartographic, topographic, and thematic mapping, and determine the optimum configuration of a SAR system for future mapping mission is outlined. SIR-B is the first orbital imaging radar mission which will incorporate maintenance of geometric image fidelity along with careful calibration and documentation of internal timing and frequency parameters. This along and and the multiple incidence angle images of the same target which are necessary for stereoscopy and topographic mapping, make it the ideal opportunity for cartographic experimentation. It is emphasized that comprises a significant part of the overall experiment objectives.

Kobrick, M.↗
NASA NTRS1984

Studies of coastal mesoscale winds using SIR-B

The variability of the mesoscale wind fields near coastlines which can be caused by mountains that shadow offshore wind and by valleys that enhance them. These wind, provide relatively fixed patterns that must be considered in the development of algorithms for future spaceborne scatterometer systems; mesoscale variability over the offshore regions is random and must be averaged out for forecasting yet nearshore fixed patterns are treated differently. Before the patterns of interest can be defined quantitatively, the scattering response of the ocean to winds at the L-band frequency and SIR-B angles of incidence must be developed from the SIR-B data. Patterns can be analyzed on the images both in regions selected for high probability of the occurrence of suitable patterns, and in other regions where the patterns are observed. The patterns are analyzed for topographic effects and the distance to sea over which these effects cause variations in the oceanic wind patterns. The results are interpreted in terms of quantitative description of the processes involved and in for need of modifications of future scatterometer algorithms.

Moore, R. K.↗
NASA NTRS1985

The effect of tantalum on the structure/properties of two polycrystalline nickel-base superalloys: B-1900 + Hf MAR-M247

The microstructure, phase compositions, and phase fractions were studied in conventionally cast B-1900 + Hf and both conventionally cast and directionally solidified MAR-M247 as a function of tantalum concentration. The hot tensile and creep rupture properties of the solutionized and aged MAR-M247-type alloys were also determined as a function of tantalum level. The effects of tantalum on the microstructure and phase compositions of B-1900 + Hf and MAR-M247 (conventionally cast and directionally solidified) were found to be very similar. The addition of tantalum to the as cast and heat treated alloys was shown to cause the partial replacement of the Hf in the MC carbides by Ta, although the degree of replacement was decreased by the solutionizing and aging heat treatment. The gamma prime and minor phase fractions (primarily MC type carbides) both increased approximately linearly with tantalum concentration. The gamma prime phase compositions were relatively insensitive to tantalum variations with the exception of the tantalum and/or hafnium levels. Bulk tantalum additions increased the tantalum, chromium, and cobalt levels of the gamma phase in both alloy series. The increase in the concentrations of the latter two elements in the gamma phase was a result of the decrease in the gamma phase fraction with increasing bulk tantalum concentration and constant gamma/gamma prime partitioning ratio. Tantalum additions increased the yield stress and ultimate tensile strength of the directionally solidified MAR-M247 type alloys and had no significant effect on ductility.

Janowski, G. M.↗
NASA NTRS1985

B-52B/DTV (Drop Test Vehicle) flight test results: Drop test missions

The NASA test airplane, B-52B-008, was a carrier for drop tests of the shuttle booster recovery parachute system. The purpose of the test support by Boeing was to monitor the vertical loads on the pylon hooks. The hooks hold the Drop Test Vehicle to the B-52 pylon during drop test missions. The loads were monitored to assure the successful completion of the flight and the safety of the crew.

Doty, L. J.↗
NASA NTRS1984

Ultraviolet studies of O and B stars in the LMC cluster NGC 2100, the SMC cluster NGC 330 and the Galactic cluster NGC 6530

High-resolution and low-resolution IUE spectra of O and B stars in the LMC cluster NGC 2100, the SMC cluster NGC 330, and the young Galactic cluster NGC 6530 are investigated. Temperatures and luminosities are determined. In the LMC and SMC clusters, the most luminous stars are evolved stars on the horizontal supergiant branch, while in NGC 6530 the stars are all still on the main sequence. Extinction laws were determined. They confirm the known differences between LMC and Galactic extinctions. No mass loss was detected for the evolved B stars in the LMC and SMC clusters, while the high-luminosity stars in NGC 6530 show P Cygni profiles.

Boehm-Vitense, E.↗
NASA NTRS1985

Transition probabilities of the B-prime 1Sigma(u)(+) to X 1Sigma(g)(+) system of molecular hydrogen

From published potential energy curves and transition dipole moments, there are obtained by numerical integration of the equations of nuclear motion the vibrational eigenfunctions of the X 1Sigma(g)(+) and B-prime 1Sigma(u)(+) states of H2. The probabilities of radiative transitions from the discrete vibrational levels of the excited B-prime 1Sigma(u)(+) electronic state of H2 to the discrete and continuum vibrational levels of the ground X 1Sigma(g)(+) electronic state are calculated. The Franck-Condon factors are also presented.

Kwok, T. L.↗
NASA NTRS1984

The origin and significance of reverse zoning in melilite from Allende Type B inclusions

Many of Type B Allende inclusions are found to have reverse zoning over restricted portions of each crystal, in contrast to those in Type A's, which are reversely zoned throughout. Results of dynamic crystallization experiments on compositions similar to an average Type B inclusion are reported in which reversely zoned melilite rims were grown on normally zoned cores. The fact that these zoning patterns have been duplicated is interpreted as evidence that natural melilites having such zoning were formed by crystallization from a melt. Since reverse zoning could only be produced over a restricted range of experimental conditions, the presence in natural inclusions of the kinds of zoning patterns described here may place constraints on the conditions under which the inclusions formed.

Macpherson, G. J.↗
NASA NTRS1986

Tensile behavior of Fe-40Al alloys with B and Zr additions

Both Fe-40Al and Fe-40Al-0.1Zr with and without B were produced by the hot extrusion of powdered metal. Tensile properties were determined from room temperature to 1100 K in air. All of the materials possessed some ductility at room temperature, and addition of B caused an increase in ductility and a change in fracture mode from intergranular to transgranular cleavage. At high temperatures, failure was caused primarily by the formation of grain boundary cavities in all of the alloys. The effect of Zr addition was unclear because of the complexity of the various microstructures. Comparison of air and vacuum testing at high temperatures revealed that an apparent oxidation assisted mechanism reduced high temperature ductility in these alloys, especially at 900 K.

Gaydosh, D. J.↗
NASA NTRS1985

Lubrication handbook for the space industry. Part A: Solid lubricants. Part B: Liquid lubricants

This handbook is intended to provide a ready reference for many of the solid and liquid lubricants used in the space industry. Lubricants and lubricant properties are arranged systematically so that designers, engineers, and maintenance personnel can conveniently locate data needed for their work. This handbook is divided into two major parts (A and B). Part A is a compilation of solid lubricant suppliers information on chemical and physical property of data of more than 250 solid lubricants, bonded solid lubricants, dispersions, and composites. Part B is a compilation of chemical and physical porperty data of more then 250 liquid lubricants, greases, oils, compounds, and fluids. The listed materials cover a broad spectrum from manufacturing and ground support to hardware applications of spacecraft.

Mcmurtrey, E. L.↗
NASA NTRS1985

Preliminary science results from the Shuttle Imaging Radar-B

Preliminary results of analyzing digital radar imagery data obtained by the SIR-B aboard the Space Shuttle Challenger STS 41-G are presented. The data cover 5 million square kilometers of the earth surface between 57 deg north and south latitudes. Radar imagery of the same target at different incidence angles was used to classify surfaces by their backscatter response as a function of incidence angle. The SIR-B proved to be useful for collecting multiple incidence angle data sets over a broad range of targets, providing information in the areas of geology, archeology, forestry, agriculture, oceanography, geography, and hydrology. The analysis is also used to optimize radar parameters such as look angle for future missions.

Ruzek, M.↗