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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 613 records · Page 34

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NASA NTRS1981

Bladed-shrouded-disc aeroelastic analyses: Computer program updates in NASTRAN level 17.7

In October 1979, a computer program based on the state-of-the-art compressor and structural technologies applied to bladed-shrouded-disc was developed. The program was more operational in NASTRAN Level 16. The bladed disc computer program was updated for operation in NASTRAN Level 17.7. The supersonic cascade unsteady aerodynamics routine UCAS, delivered as part of the NASTRAN Level 16 program was recorded to improve its execution time. These improvements are presented.

Gallo, A. M.↗

NASA NTRS1985

1000 GeV gamma rays from Cygnus X-3: An update

Measurements of 1000 GeV gamma-rays from Cygnus X-3 made with the University of Durham facility at Dugway, Utah in 1981/82 are reviewed. The light curve of the 4.8 hour modulated emission is updated and shows evidence significant at the 4.4 sigma level for strong emission (9% of the cosmic ray rate) at phase 0.625 and less significant (1.4 sigma level) indications of weaker emission (3% of the cosmic ray rate) at phase 0.125. The effect constituting the excess on the few nights showing the strongest emission appears to arise from the smallest Cerenkov light signals suggesting a steep gamma-ray spectrum. The 1982 data have been searched unsuccessfully for evidence of emission at phase 0.2, in coincidence with the results from the ultra-high energy (extensive Air Showers (EAS) measurements in 1979-1982. A systematic investigation of a long term variation in the strength of the peak of the 4.8 hr modulated 1000 GeV gamma-ray emission has been made. We find that in addition to the approximately 34 d variation reported by us previously, a stronger effect exists at around 19d.

Chadwick, P. M.↗

NASA NTRS1985

An update on the correlation between the cosmic radiation intensity and the geomagnetic AA index

A statistical study between the cosmic ray intensity, as observed by a neutron monitor, and of the geomagnetic aa index, as representative of perturbations in the plasma and interplanetary magnetic field in the heliosphere, has been updated to specifically exclude time periods around the reversal of the solar magnetic field. The results of this study show a strong negative correlation for the period 1960 through 1968 with a correlation coefficient of approximately -0.86. However, there is essentially no correlation between the cosmic ray intensity and the aa index for the period 1972-1979 (i.e. correlation coefficient less than 0.16). These results would appear to support the theory of preferential particle propagation into the heliosphere vis the ecliptic during the period 1960-1968 and via the solar polar regions during 1972-1979.

Shea, M. A.↗

NASA NTRS1984

Ultraviolet spectroscopy of cometary comae - An update

This report provides an update to the reviews of ultraviolet spectroscopy of comets presented by Feldman (1982, 1983). Recent developments are largely related to the use of the International Ultraviolet Explorer (IUE), which to date has now observed approximately 20 comets. Distant, dusty comets are considered, taking into account Comet Bowell (1982 I), and Comet Cernis (1983l). Attention is also given to earth-approaching comets, the periodic Comet Encke in 1980 and 1984, and planned ultraviolet observations of P/Halley. It is pointed out that a large number of ultraviolet spectroscopic and imaging programs are planned for the 1985-86 apparition of Comet Halley utilizing encounter spacecraft, satellite and Space Shuttle borne observatories, and suborbital sounding rocket flights.

Feldman, P. D.↗

NASA NTRS1985

An update of spacecraft dynamic environments induced by ground transportation

An update to a spacecraft transportation dynamic environments data base was developed based on data from recent transportation of spacecrafts. Vibration levels are significantly lower than those measured in 1966, while the shock response spectra are nearly the same. Ground shipping criteria and shipping practices, which have been very successful in preventing damage, are also summarized.

Oconnell, N. R.↗

NASA NTRS1987

Updated Conceptual Cost Estimating

16-page report discusses development and use of NASA TR-1508, the Kennedy Space Center Aerospace Construction Price Book for preparing conceptual, budget, funding, cost-estimating, and preliminary cost-engineering reports. Updated annually from 1974 through 1985 with actual bid prices and government estimates. Includes labor and material quantities and prices with contractor and subcontractor markups for buildings, facilities, and systems at Kennedy Space Center. While data pertains to aerospace facilities, format and cost-estimating techniques guide estimation of costs in other construction applications.

Brown, J. A.↗

NASA NTRS1988

Optimizing advanced propeller designs by simultaneously updating flow variables and design parameters

A scheme is developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The scheme updates the design parameter iterative solutions and the flow variable iterative solutions simultaneously. It is applied to an advanced propeller design problem with the Euler equations used as the flow governing equations. The scheme's accuracy, efficiency and sensitivity to the computational parameters are tested.

Rizk, Magdi H.↗

NASA NTRS1988

Optical correlators with fast updating speed using photorefractive semiconductor materials

The performance of an updatable optical correlator which uses a photorefractive semiconductor to generate real-time matched filters is discussed. The application of compound semiconductors makes possible high-speed operation and low optical input intensities. The Bragg diffraction is considered, along with the speed and power characteristics of these materials. Experimental results on photorefractive GaAs are presented.

Gheen, Gregory↗

NASA NTRS1988

Aerodynamic optimization by simultaneously updating flow variables and design parameters with application to advanced propeller designs

Rizk, Magdi H.↗

NASA NTRS1988

User's manual for an aerodynamic optimization scheeme that updates flow variables and design parameters simultaneously

This user's manual is presented for an aerodynamic optimization program that updates flow variables and design parameters simultaneously. The program was developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The program was tested by applying it to the problem of optimizing propeller designs. Some reference to this particular application is therefore made in the manual. However, the optimization scheme is suitable for application to general aerodynamic design problems. A description of the approach used in the optimization scheme is first presented, followed by a description of the use of the program.

Rizk, Magdi H.↗

NASA NTRS1988

Reference coordinate systems: An update. Supplement 11

A common requirement for all geodetic investigations is a well-defined coordinate system attached to the earth in some prescribed way, as well as a well-defined inertial coordinate system in which the motions of the terrestrial frame can be monitored. The paper deals with the problems encountered when establishing such coordinate systems and the transformations between them. In addition, problems related to the modeling of the deformable earth are discussed. This paper is an updated version of the earlier work, Reference Coordinate Systems for Earth Dynamics: A Preview, by the author.

Mueller, Ivan I.↗

NASA NTRS1989

An update of commercial infrared sensing and imaging instruments

A classification of infrared sensing instruments by type and application, listing commercially available instruments, from single point thermal probes to on-line control sensors, to high speed, high resolution imaging systems is given. A review of performance specifications follows, along with a discussion of typical thermographic display approaches utilized by various imager manufacturers. An update report on new instruments, new display techniques and newly introduced features of existing instruments is given.

Kaplan, Herbert↗

NASA NTRS1990

National Educators' Workshop: Update 1989 Standard Experiments in Engineering Materials Science and Technology

Presented here is a collection of experiments presented and demonstrated at the National Educators' Workshop: Update 89, held October 17 to 19, 1989 at the National Aeronautics and Space Administration, Hampton, Virginia. The experiments related to the nature and properties of engineering materials and provided information to assist in teaching about materials in the education community.

Gardner, James E.↗

NASA NTRS1990

Solar radiation on Mars: Update 1990

Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. The authors present a procedure and solar radiation related data from which the diurnally and daily variation of the global, direct beam and diffuse insolation on Mars are calculated. The radiation data are based on measured optical depth of the Martian atmosphere derived from images taken of the Sun with a special diode on the Viking Lander cameras and computation based on multiple wavelength and multiple scattering of the solar radiation. This work is an update to NASA-TM-102299 and includes a refinement of the solar radiation model.

Appelbaum, Joseph↗

NASA NTRS1991

METCAN updates for high temperature composite behavior: Simulation/verification

The continued verification (comparisons with experimental data) of the METCAN (Metal Matrix Composite Analyzer) computer code is updated. Verification includes comparisons at room and high temperatures for two composites, SiC/Ti-15-3 and SiC/Ti-6-4. Specifically, verification of the SiC/Ti-15-3 composite includes comparisons of strength, modulus, and Poisson's ratio as well as stress-strain curves for four laminates at room temperature. High temperature verification includes comparisons of strength and stress-strain curves for two laminates. Verification of SiC/Ti-6-4 is for a transverse room temperature stress-strain curve and comparisons for transverse strength at three temperatures. Results of the verification indicates that METCAN can be used with confidence to simulate the high temperature nonlinear behavior of metal matrix composites.

Lee, H.-J.↗

NASA NTRS1990

National Educators' Workshop: Update 1988. Standard Experiments in Engineering Materials Science and Technology

Presented here is a collection of experiments presented and demonstrated at the National Educators' Workshop: Update 88, held May 10 to 12, 1988 at the National Institute of Standards and Technology (NIST), Gaithersberg, Maryland. The experiments related to the nature and properties of engineering materials and provided information to assist in teaching about materials in the education community.

Gardner, James E.↗

NASA NTRS1991

Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells. An update

An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

Smithrick, John J.↗

NASA NTRS1990

The 1990 update to strategy for exploration of the inner planets

The Committee on Planetary and Lunar Exploration (COMPLEX) has undertaken to review and revise the 1978 report Strategy for Exploration of the Inner Planets, 1977-1987. The committee has found the 1978 report to be generally still pertinent. COMPLEX therefore issues its new report in the form of an update. The committee reaffirms the basic objectives for exploration of the planets: to determine the present state of the planets and their satellites, to understand the processes active now and at the origin of the solar system, and to understand planetary evolution, including appearance of life and its relation to the chemical history of the solar system.

Esposito, Larry W.↗