Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Area of Review”

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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Power processing for electric propulsion

The inclusion of electric thruster systems in spacecraft design is considered. The propulsion requirements of such spacecraft dictate a wide range of thruster power levels and operational lifetimes, which must be matched by lightweight, efficient, and reliable thruster power processing systems. Electron bombardment ion thruster requirements are presented, and the performance characteristics of present power processing systems are reviewed. Design philosophies and alternatives in areas such as inverter type, arc protection, and control methods are discussed along with future performance potentials for meeting goals in the areas of power process or weight (10 kg/kW), efficiency (approaching 92 percent), reliability (0.96 for 15,000 hr), and thermal control capability (0.3 to 5 AU).

Finke, R. C.↗
NASA NTRS1975

Advanced short haul systems in high density markets

The design requirements, performance, economics, and noise aspects of STOL and VTOL conceptual aircraft developed for short haul air transportation are reviewed, along with the characteristics of areas of high-density annual passenger flow in which the aircraft are intended to operate. It is shown that aircraft of 100 to 200 passenger capacity provide the best return on investment in high density markets. The various STOL propulsive lift concepts have the same general trends with field length; their wing loadings are 20 to 30 pounds per square foot higher than the nonpropulsive lift concepts. A comparison of the aircraft under consideration shows that no one aircraft concept will be optimum for all future operational environments.

Galloway, T. L.↗
NASA NTRS1975

Strainrange Partitioning - A tool for characterizing high-temperature low-cycle fatigue

The basic concepts of Strainrange Partitioning are reviewed, with particular reference to the areas requiring expanded verification. A cooperative program is proposed for achieving this broader verification through the additional experience provided by the participants in this program. The suggested program includes verification of the four basic life relationships (for PP, CC, PC, and CP type inelastic strainranges) for a variety of materials chosen by the participating organizations. The four relationships are then used in conjunction with the Interaction Damage Rule to predict the cyclic lives of tests involving various combinations of the basic strainrange components. The testing program also includes evaluation of the degree of insensitivity of these relationships to temperature as well as their utility in representing bounds on life.

Hirschberg, M. H.↗
NASA NTRS1977

Impact of alternative energy forms on public utilities

The investigation of alternative energy sources by the electric utility industry is discussed. Research projects are reviewed in each of the following areas; solar energy, wind energy conversion, photosynthesis of biomass, ocean thermal energy conversion, geothermal energy, fusion, and the environmental impact of alternative energy sources.

Keith, F. W., Jr.↗
NASA NTRS1978

The promise of advanced technology for future air transports

Progress in all weather 4-D navigation and wake vortex attenuation research is discussed and the concept of time based metering of aircraft is recommended for increased emphasis. The far term advances in aircraft efficiency were shown to be skin friction reduction and advanced configuration types. The promise of very large aircraft, possibly all wing aircraft is discussed, as is an advanced concept for an aerial relay transportation system. Very significant technological developments were identified that can improve supersonic transport performance and reduce noise. The hypersonic transport was proposed as the ultimate step in air transportation in the atmosphere. Progress in the key technology areas of propulsion and structures was reviewed. Finally, the impact of alternate fuels on future air transports was considered and shown not to be a growth constraint.

Bower, R. E.↗
NASA NTRS1977

Organic matter in eolian dusts over the Atlantic Ocean

The elemental and mineralogical composition and the microfossil and detritus content of particulate fallout from the lower troposphere over the Atlantic Ocean have been extensively documented in earlier work, and it was possible to ascribe terrigenous source areas to such fallout. A brief review of the organic geochemistry of eolian dusts is also presented here. The lipids of eolian dusts sampled from the air mass over the eastern Atlantic from about 35 deg N to 30 deg S were analyzed here. These lipids consisted mainly of normal alkanes, carboxylic acids and alcohols. The n-alkanes were found to range from n-C23 to n-C35 with high CPI values and maximizing at n-C27 in the North Atlantic, at n-C29 in the equatorial Atlantic and at n-C31 in the South Atlantic. The n-fatty acids had mostly bimodal distributions, ranging from n-C12 to n-C30 (high CPI), with maxima at n-C16 and in the northern samples at n-C24 and in the southern samples at n-C26. The n-alcohols ranged from n-C12 to n-C32, with high CPI values and maxima mainly at n-C28. The compositions of these lipids indicated that their terrigenous sources were comprised mainly of higher plant vegetation and desiccated lacustrine mud flats on the African continent.

Simoneit, B. R. T.↗
NASA NTRS1979

Recent developments in PMR polyimides at NASA Lewis

The following areas of PMR polyimide research were reviewed: (1) prepreg tack and drape; (2) cure temperature; (3) solution characterization; and (4) elevated temperature composite properties. Recent hardware applications of PMR-15 by various fabricators were also reviewed.

Serafini, T. T.↗
NASA NTRS1981

Planning assistance for the 30/20 GHz program, volume 2

In the baseline concept development the communications payload on Flight 1 was specified to consist of on-board trunking and emergency communications systems (ECS). On Flight 2 the communications payloads consisted of trunking and CPS on-board systems, the CPS capability replacing the Flight 1 ECS. No restriction was placed on the launch vehicle size. Constraints placed on multiple concept development effort were that launch vehicle size for Concept 1 was restricted to SUSS-D and for Concept 2 a SUSS-A. The design concept development was based on satisfying the baseline requirements set forth in the SOW for a single demonstration flight system. Key constraints on contractors were cost and launch vehicle size. Five major areas of new technology development were reviewed: (1) 30 GHz low noise receivers; (2) 20 GHz Power Amplifiers; (3) SS-TDMA switch; (4) Baseband Processor; (5) Multibeam Antennas.

Al-Kinani, G.↗
NASA NTRS1984

Ground-based Measurements of Solar Irradiance Variations

Observations and analysis programs being carried out at the San Fernando Observatory are reviewed. A digital analysis of sunspot areas from full disk photographs shows an especially good correlation with areas published in the Solar Geophysical Data Bulletin with scale factor near unity. Results are presented from photoelectric photometry of active regions using the Extreme Limb Photometer. These results suggest energy balance between sunspots and faculae. Preliminary results are presented from a new program of photoelectric photometry using a linear array of diodes. Results are presented for the August 1982 passage of a large active region. This active region caused a maximum dip in the quiet Sun irradiance of about 800 parts per million.

Chapman, G. A.↗
NASA NTRS1987

An overview of the DOE terrestrial crystalline solar cell research program

There has been significant progress in the crystalline solar cell area in the past two years that has rejuvenated interest in the high efficiency devices for terrestrial photovoltaic systems. The most significant developments have been in the crystalline solar cell area, but progress in the III-V area has also been recorded. A review of terrestrial crystalline cell research is presented along with a description of future research directions.

Gee, James M.↗
NASA NTRS1987

Space Station Mission Planning System (MPS) development study. Volume 2

The process and existing software used for Spacelab payload mission planning were studied. A complete baseline definition of the Spacelab payload mission planning process was established, along with a definition of existing software capabilities for potential extrapolation to the Space Station. This information was used as a basis for defining system requirements to support Space Station mission planning. The Space Station mission planning concept was reviewed for the purpose of identifying areas where artificial intelligence concepts might offer substantially improved capability. Three specific artificial intelligence concepts were to be investigated for applicability: natural language interfaces; expert systems; and automatic programming. The advantages and disadvantages of interfacing an artificial intelligence language with existing FORTRAN programs or of converting totally to a new programming language were identified.

Klus, W. J.↗
NASA NTRS1987

Aeropropulsion 1987. Session 6: High-Speed Propulsion Technology

NASA is conducting aeronautical research over a broad range of Mach numbers. In addition to the advanced CTOL propulsion research described in a separate session, the Lewis Research Center has intensified its efforts towards propulsion technology for selected high-speed flight applications. In a companion program, the Langley Research Center has also accomplished excellent research in Supersonic Combustion Ramjet (SCRAM) propulsion. What is presented in this session is an unclassified review of some of the propulsion research results that are applicable for supersonic to hypersonic vehicles. Not only is a review provided for several key work areas, it also presents a viewpoint on future research directions by calling attention to cycles, components, and facilities involved in this rapidly expanding field of work.

Source record↗
NASA NTRS1988

SIRTF and solar system studies

Current objectives of infrared studies of solar system bodies are reviewed, and the contributions in this area that SIRTF can make are addressed. Primordial issues, the evolution of giant planet atmospheres and satellites, seasonal processes in giant planet atmospheres and satellites, the comets, the asteroids, interplanetary matter, and the detection of extrasolar planetary systems are considered. The role of SIRTF in the Comet Rendezvous Asteroids Flyby (CRAF) mission is examined.

Cruikshank, Dale P.↗
NASA NTRS1988

Recent developments in structural sensitivity analysis

Recent developments in two areas of structural sensitivity analysis are reviewed. These are the sensitivity of static and transient response, and the sensitivity of vibration and buckling eigenproblems. Recent developments from the point of view of computational cost, accuracy, and ease of implementation are considered.

Haftka, Raphael T.↗
NASA NTRS1989

Fluid flow analysis of the SSME high pressure fuel and oxidizer turbine coolant systems

The objective is to provide improved analysis capability for the Space Shuttle Main Engine (SSME) high pressure fuel and oxidizer turbine coolant systems. Each of the systems was analyzed to determine fluid flow rate and thermodynamic and transport properties at all key points in the systems. Existing computer codes were used as a baseline for these analyses. These codes were modified to provide improved analysis capability. The major areas of improvement are listed. A review of the drawings was performed, and pertinent geometry changes were included in the models. Improvements were made in the calculation of thermodynamic and transport properties for a mixture of hydrogen and steam. A one-dimensional turbine model for each system is included as a subroutine to each code. This provides a closed loop analysis with a minimum of required boundary conditions as input. An improved labyrinth seal model is included in the high pressure fuel turbine coolant model. The modifications and the analysis results are presented in detail.

Teal, G. A.↗
NASA NTRS1991

Magnetospheric radio and plasma wave research - 1987-1990

This review covers research performed in the area of magnetospheric plasma waves and wave-particle interactions as well as magnetospheric radio emissions. The report focuses on the near-completion of the discovery phase of radio and plasma wave phenomena in the planetary magnetospheres with the successful completion of the Voyager 2 encounters of Neptune and Uranus. Consideration is given to the advances made in detailed studies and theoretical investigations of radio and plasma wave phenomena in the terrestrial magnetosphere or in magnetospheric plasmas in general.

Kurth, W. S.↗
NASA NTRS1992

Evaluation of human response to structural vibrations induced by sonic booms

The topic is addressed of building vibration response to sonic boom and the evaluation of the associated human response to this vibration. An attempt is made to reexamine some of the issues addressed previously and to offer fresh insight that may assist in reassessing the potential impact of sonic boom over populated areas. Human response to vibration is reviewed first and a new human vibration response criterion curve is developed as a function of frequency. The difference between response to steady state versus impulsive vibration is addressed and a 'vibration exposure' or 'vibration energy' descriptor is suggested as one possible way to evaluate duration effects on response to transient vibration from sonic booms. New data on the acoustic signature of rattling objects are presented along with a review of existing data on the occurrence of rattle. Structural response to sonic boom is reviewed and a new descriptor, 'Acceleration Exposure Level' is suggested which can be easily determined from the Fourier Spectrum of a sonic boom. A preliminary assessment of potential impact from sonic booms is provided in terms of human response to vibration and detection of rattle based on a synthesis of the preceding material.

Sutherland, Louis C.↗
NASA NTRS1992

Microgravity vibration isolation research at the University of Virginia

Research at the University of Virginia on microgravity vibration isolation is reviewed. This work falls into three areas: the one degree of freedom isolation test rig and Lorentz actuator design, multiple degree of freedom active isolation system control, and innovative actuators for long stroke, non-contacting six degree of freedom isolation. Theoretical and design issues of multiple degree of freedom isolation are discussed.

Knospe, Carl R.↗