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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Elevated temperature deformation of TD-nickel base alloys

Sensitivity of the elevated temperature deformation of TD-nickel to grain size and shape was examined in both tension and creep. Elevated temperature strength increased with increasing grain diameter and increasing L/D ratio. Measured activation enthalpies in tension and creep were not the same. In tension, the internal stress was not proportional to the shear modulus. Creep activation enthalpies increased with increasing L/D ratio and increasing grain diameter, to high values compared with that of the self diffusion enthalpy. It has been postulated that two concurrent processes contribute to the elevated temperature deformation of polycrystalline TD-nickel: (1) diffusion controlled grain boundary sliding, and (2) dislocation motion.

Petrovic, J. J.↗
NASA NTRS1972

Plasma wave observations near the plasmapause with the S3-A satellite

The electric field noise phenomena is described which was observed by the S3-A spacecraft near the plasmapause during the magnetic storm of 16 to 17 December, 1971. The occurrence is noted of a region of intense, low frequency (20 Hz to 500 Hz) electrostatic noise bursts just outside the plasmapause boundary. These noise bursts occurred concurrent with the rapid decrease in 24.3 or = E or = 35.1 keV ring current protons mirroring near the equator during this storm and may be responsible for the pitch angle diffusion and loss of these particles. The characteristics of other phenomena, such as whistlers, ELF hiss, and banded chorus, observed near the plasmapause during this period are also discussed.

Anderson, R. R.↗
NASA NTRS1973

Combustion detector

A device has been developed for generating a rapid response signal upon the radiation-emitting combustion reaction of certain gases in order to provide a means for the detection and identification of such reaction and concurrently discriminate against spurious signals. This combustion might be the first stage of a coal mine explosion process, and thereby this device could provide a warning of the impending explosion in time to initiate quenching action. This device has the capability of distinguishing between the light emitted from a combustion reaction and the light emitted by miners' lamps, electric lamps, welding sparks or other spurious events so that the quenching mechanism is triggered only when an explosion-initiating combustion occurs.

Trimpi, R. L.↗
NASA NTRS1973

Microbiological sampling of spacecraft cabling, antennas, solar panels and thermal blankets

Sampling procedures and techniques described resulted from various flight project microbiological monitoring programs of unmanned planetary spacecraft. Concurrent with development of these procedures, compatibility evaluations were effected with the cognizant spacecraft subsystem engineers to assure that degradation factors would not be induced during the monitoring program. Of significance were those areas of the spacecraft configuration for which special handling precautions and/or nonstandard sample gathering techniques were evolved. These spacecraft component areas were: cabling, high gain antenna, solar panels, and thermal blankets. The compilation of these techniques provides a historical reference for both the qualification and quantification of sampling parameters as applied to the Mariner Spacecraft of the late 1960's and early 1970's.

Koukol, R. C.↗
NASA NTRS1973

The circulation of Prince William Sound

The author has identified the following significant results. Results suggest that sediment-laden plumes of fresh water from rivers may be useful tracers, due to their high visibility, of surface water motion. The two useable images obtained to date corroborate that westerly flow was occurring in the Gulf of Alaska just south of Prince William Sound, and that an inflow into Prince William Sound was occurring concurrently with flood tides on both occasions. River plumes are useful tracers, but poor weather conditions somewhat limit the use of satellite imagery.

Muench, R. D.↗
NASA NTRS1973

Odor intensity and characterization of jet exhaust and chemical analytical measurements

Odor and chemical analyses were carried out on the exhaust samples from a J-57 combustor can operated over a range of inlet conditions, and with several fuel types and nozzle modifications. The odor characteristics and total intensity of odor for each exhaust were determined over a range of dilutions to allow for a least squares determination of the intensity at 1,000 to 1 dilutions. Analytical measures included the concentration of total hydrocarbons and the concentrations of aromatic organic species and oxygenated organic species from collected samples which were taken concurrently. A correlation was found between the concentration of the odorous oxygenated fraction and the total intensity of aroma. Inlet operating conditions and nozzle modifications which increase the efficiency of combustion as measured by exhaust gas analyses reduce the odor intensity and the quantity of oxygenates in the exhaust. The type of fuel burned altered the intensity of odor in relation to the quantity of oxygenates produced and, in some instances, changed the odor character.

Kendall, D. A.↗
NASA NTRS1972

Long life assurance study for manned spacecraft long life hardware. Volume 1: Summary of long life assurance guidelines

A long life assurance program for the development of design, process, test, and application guidelines for achieving reliable spacecraft hardware was conducted. The study approach consisted of a review of technical data performed concurrently with a survey of the aerospace industry. The data reviewed included design and operating characteristics, failure histories and solutions, and similar documents. The topics covered by the guidelines are reported. It is concluded that long life hardware is achieved through meticulous attention to many details and no simple set of rules can suffice.

Source record↗
NASA NTRS1973

Evaluation of ERTS data for certain hydrological uses

The author has identified the following significant results. Melting ice has been detected in Lake Erie by comparison of visible and near infrared differential reflectance. This melting condition is confirmed by meteorological ground truth data and concurrent NOAA-2 thermal infrared data. Using near-synchronous ERTS-1 data, it was possible to determine the approximate ground resolution of NOAA-2 very high resolution radiometer by comparing the smallest identifiable ice crack in the imagery and measuring the same crack on the ERTS-1 image. It was determined that photointerpretation and analysis of a single Lake Erie image can, under certain conditions, provide meaningful data on ice dynamics. ERTS-1 imagery is effective for icepack monitoring of the Great Lakes, but the sampling interval of 18 days imposes a severe limitation. Maps of the snow cover in the American River basin for 16 March 1973 have been prepared using all four bands.

Wiesnet, D. R.↗
NASA NTRS1973

Regeneratively cooled rocket engine for space storable propellants

Analysis, design, fabrication, and test efforts were performed for the existing OF2/B2H6 regeneratively cooled lK (4448 N) thrust chamber to illustrate simultaneous B2H6 fuel and OF2 oxidizer cooling and to provide results for a gaseous propellant condition injected into the combustion chamber. Data derived from performance, thermal and flow measurements confirmed predictions derived from previous test work and from concurrent analytical study. Development data derived from the experimental study were indicated to be sufficient to develop a preflight thrust chamber demonstrator prototype for future space mission objectives.

Wagner, W. R.↗
NASA NTRS1972

Nonlinear and Digital Man-machine Control Systems Modeling

An adaptive modeling technique is examined by which controllers can be synthesized to provide corrective dynamics to a human operator's mathematical model in closed loop control systems. The technique utilizes a class of Liapunov functions formulated for this purpose, Liapunov's stability criterion and a model-reference system configuration. The Liapunov function is formulated to posses variable characteristics to take into consideration the identification dynamics. The time derivative of the Liapunov function generate the identification and control laws for the mathematical model system. These laws permit the realization of a controller which updates the human operator's mathematical model parameters so that model and human operator produce the same response when subjected to the same stimulus. A very useful feature is the development of a digital computer program which is easily implemented and modified concurrent with experimentation. The program permits the modeling process to interact with the experimentation process in a mutually beneficial way.

Mekel, R.↗
NASA NTRS1973

Enriched aluminide coatings for dispersion strengthened nickel materials

Improved aluminide/barrier coating combinations for dispersion strengthened nickel materials were investigated. The barrier materials involved alloys with refractory metal content to limit interdiffusion between the coating and the substrate, thereby minimizing void formation. Improved aluminide coatings involved the dispersion of aluminum-rich compounds. Coatings were tested in argon at 1533 K (2300 F) for 100 hours and in cyclic oxidation at 1422 K (2100 F). Two coatings on TDNiCr completed 300 hours of oxidation testing, none on TDNi. Selected coating combinations were evaluated in Mach 1 burner rig testing using JP-4 fuel and air at 1422 K (2100 F) and 1477 K (2200 F) for 350 and 100 hours, respectively. Static oxidation in 1-hour cycles was conducted at 1533 K (2300 F) for 100 hours. For comparison purposes a physical vapor deposition (PVD) NiCrAlY coating was tested concurrently. Only the NiCrA1Y coating survived the 1477 K (2200 F)/100-hour burner rig test and 275 hours of the 350-hour 1422 K (2100 F) test. Elevated temperature exposure reduced room temperature tensile properties but had little effect on elevated temperature properties.

Levinstein, M. A.↗
NASA NTRS1973

The Delta Launch Vehicle Model 2914 Series

The newest Delta launch vehicle configuration, Model 2914 is described for potential users together with recent flight results. A functional description of the vehicle, its performance, flight profile, flight environment, injection accuracy, spacecraft integration requirements, user organizational interfaces, launch operations, costs and reimbursable users payment plan are provided. The versatile, relatively low cost Delta has a flight demonstrated reliability record of 92 percent that has been established in 96 launches over twelve years while concurrently undergoing ten major upratings to keep pace with the ever increasing performance and reliability requirements of its users. At least 40 more launches are scheduled over the next three years from the Eastern and Western Test Ranges.

Gunn, C. R.↗
NASA NTRS1973

Automatic photointerpretation for land use management in Minnesota

The author has identified the following significant results. Progress is being made in the areas of sun angle and atmospheric effects on the data and its interpretation. The effort is aimed at correction using only navigation and calendar data needed for satellite operation and derivations from the MSS data. Water estimation of value to land planners and conservationists has been demonstrated with verification of performance by comparison with a concurrent study involving map planimetry, aerial photos, and field-checking. The satellite will provide seasonal and annual coverage with timely information in a way not now feasible by conventional methods. For example, the reference data were obtained using the most recent files, which date back to 1949, and from most recent photography taken in 1968. The calendar time involved was three to four months, which is a reflection on priority pressure on trained manpower available. ERTS-1 data can help relieve this problem by providing the needed information while freeing trained manpower for more appropriate parts of the effort.

Swanlund, G. D.↗
NASA NTRS1972

Simulator evaluation of the flying qualities of externally blown flap and augmentor wing transport configurations

Concurrent simulations of powered-lift STOL transport aircraft having either an externally blown flap configuration or an augmentor wing configuration were conducted. The following types of simulators of varying sophistication were used: (1) a simple fixed-base simulation with a simple visual display, (2) a more complex fixed-base simulation using a realistic transport cockpit and a high-quality visual display, and (3) a six-degree-of-freedom motion simulator that had a realistic transport cockpit and a sophisticated visual display. The unaugmented flying qualities determined from these simulations were rated as unacceptable for both the externally blown flap and augmentor wing configurations. The longitudinal, lateral-directional, and single-engine-failure characteristics were rated satisfactory with extensive augmentation, including pitch and roll command systems, flight-path (or speed) augmentation, turn coordination, and effective yaw damping. However, the flare and landing characteristics from any approach glide-path angle in excess of 4 deg were rated as unsatisfactory but acceptable.

Kier, D. A.↗
NASA NTRS1972

A multispectral cloud type identification method using Nimbus 3 MRIR measurements.

Using Nimbus 3 medium resolution infrared radiometer measurements, a multispectral cloud type identification method is developed. This method includes a fourth spectral region (20-23 microns), the use of radiative transfer theory, and a semiquantitative evaluation of satellite cloud type estimates with concurrent high resolution photography from aircraft flights.

Shenk, W. E.↗
NASA NTRS1973

The extreme ultraviolet emissions of solar flares - A comparison between OSO-6 spectroheliograph observations and SFDs.

The time structure and intensity of OSO-6 observations of EUV bursts were studied in relation to the corresponding 10-1030 A enhancements deduced from SFD data. Impulsive EUV emissions from lines normally emitted from either the chromosphere or from the chromosphere-corona transition region rise simultaneously with the 10-1030 A flash, to within the time resolution of the OSO-6 observations. Mg X 625 A also showed concurrent impulsive emissions and a close intensity relation to the 10-1030 A enhancement. The observational results are consistent with the hypothesis that most of the EUV radiation is being produced thermally in a region of chromospheric density, which is being heated by collisional losses of nonthermal electrons.

Donnelly, R. F.↗
NASA NTRS1972

Are lunar rilles inverted eskers.

A proposed mechanism for the formation of lunar rilles argues that escaping volatiles (CO2 and H2O) could produce a sinuous channel between an impermeable basement surface and a developing surficial permafrost layer. Concurrent with the development of the subsurface channel would be the production of a large amount of fragmented ice mixed with rock debris at the surface above and along the sides of the sinuous subsurface channel. Eventual sublimation of the ice in the surficial material down to and perhaps including the subsurface would develop a feature at the surface that would be morphologically very similar to a valley produced by running water.

Helsley, C. E.↗
NASA NTRS1973

Electron density profiles from ionograms - Comparisons with rocket profiles.

From a series of ten rocket flights at Wallops Island conducted by the University of Illinois, detailed electron density profiles are available in the altitude range 60-120 km. Concurrent ionograms from a nearby conventional ionosonde of good sensitivity and precision, have been reduced to N(h) profiles by the NOAA methods. Special attention is given to the needs for accurate ionosonde calibration, proper ionogram interpretation, and corrections for underlying ionization, 'valley' ionization, and effects of lateral-gradients. Proper corrections in the present cases yield profiles by ionogram inversion which agree to within a few percent in density, and a few hundred meters or less in height, with the rocket results.

Wright, J. W.↗