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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 NTRS1979

Conceptual design study of an Improved Gas Turbine (IGT) powertrain

Design concepts for an improved automotive gas turbine powertrain are discussed. Twenty percent fuel economy improvement (over 1976), competitive costs (initial and life cycle), high reliability/life, low emissions, and noise/safety compliance were among the factors considered. The powertrain selected consists of a two shaft gas turbine engine with variable geometry aerodynamic components and a single disk rotating regenerator. The regenerator disk, gasifier turbine rotor, and several hot section flowpath parts are ceramic. The powertrain utilizes a conventional automatic transmission. The closest competitor was a single shaft turbine engine matched to a continuously variable transmission (CVT). Both candidate powertrain systems were found to be similar in many respects; however, the CVT represented a significant increase in development cost, technical risk, and production start-up costs over the conventional automatic transmission. Installation of the gas turbine powertrain was investigated for a transverse mounted, front wheel drive vehicle.

Johnson, R. A.↗
NASA NTRS1979

High Efficiency, High Density Terrestrial Panel

Terrestrial panels were fabricated using rectangular cells. Packing densities in excess of 90% with panel conversion efficiencies greater than 13% were obtained. Higher density panels can be produced on a cost competitive basis with the standard salami panels.

Wohlgemuth, J.↗
NASA NTRS1979

Making it in academic psychology: Demographic and personality correlates of eminence

Citations to published work, personality, and demographic characteristics were examined in a sample of male and female academic psychologists. A large sex difference was found in citations with men receiving significantly more recognition. Reputational rankings of graduate school and current institution were significantly related to citations, as were components of achievement motivation. Mastery and work needs were positively related to citations while competitiveness was negatively associated with the criterion. A model of attainment in psychology is proposed and possible explanations for the differential recognition of women are explored.

Helmreich, R. L.↗
NASA NTRS1979

Development of tunable high pressure CO2 laser for lidar measurements of pollutants and wind velocities, January 1976 to December 1977

A tunable multiatmospheric pulsed CO2 laser with emphasis on experimental features and supporting theoretical analyses important to differential absorption lidar and Doppler lidar measurement of pollutants and wind velocities is reported. The energy deposition and the means to produce the uniform high density plasma in the multiatmospheric medium, through UV preionization of an organic seed gas is discussed. Design features of the pulsed CO2 laser are presented. The radiative processes which are operative and prevent the laser from breaking into oscillations in a large number of modes over its broad amplification bandwidth are described. The mode competition for the transient pulsed laser oscillation in a standing wave and traveling wave ring laser configuration is discussed and contrasted with the approach to steady state oscillations. The latter findings are important to transient injection locking for production of a highly stable pulsed CO2 laser output.

Javan, A.↗
NASA NTRS1977

The trapped mercury ion frequency standard

Singly ionized mercury atoms have a structure similar to neutral alkali atoms. They can be maintained as ions for very long times in an RF quadrupole ion trap. Thus, their ground state hyperfine structure can be used to make a frequency standard using optical pumping techniques similar to the well-known rubidium standard. The mass 199 isotope of mercury has an ionic hyperfine structure of 40.5 GHz. In a trap system a linewidth of 10 Hz has been measured. An expression is presented for the short-term stability of a proposed mercury standard as set by the achieved signal to noise ratio. There is prospect of further improvement. Long-term stability is affected by second order doppler effect, and by pressure, light, and Stark shifts. However, these appear either sufficiently small or sufficiently controlable that the proposed mercury ion standard would be competitive with existing standards.

Mcguire, M. D.↗
NASA NTRS1978

Pyrolysis and oxidation of aromatic compounds

A study of the questions associated with the use of alternate fuels demands knowledge of the chemical mechanism of pyrolysis and oxidation of aromatic compounds. Both pyrolysis and oxidation are important, because fuel-rich conditions may mean that pyrolysis is competitive with oxidation. Soot formation is certainly a pyrolysis problem. The complexity of system characteristics makes a detailed study of thermodynamical and kinetic conditions difficult. The matter can be simplified somewhat by generalizing the chemistry by classes of molecules. The criteria for such a generalization of the chemistry are discussed along with an evaluation of the rate constants and their temperature and pressure dependences. Attention is given to the pyrolysis of hydrocarbons, the oxidation of hydrocarbons, the oxidation reactions of alkanes, aspects of codification and extrapolation, group additivity, structural consideration, kinetics, and the pyrolysis of aromatic compounds.

Golden, D. M.↗
NASA NTRS1978

Laser aircraft propulsion

The concept of using a high energy continuous wave laser beam from a power satellite in geosynchronous orbit to power a commercial air transport during cruise, i.e., a laser-powered airplane, is examined. These studies indicate that a laser powered airplane is a nearly fuelless and pollution-free flight transportation system which is cost competitive with the fuel conservative air transport of the future. This laser flight system involves the integration of a conventional aircraft with a laser power satellite and a set of laser driven turbofans, all of which can be fabricated with existing or projected technology. The dominant cost of the laser-powered flight transportation system is the cost of the power satellite.

Hertzberg, A.↗
NASA NTRS1979

A Mars airplane

An airplane specifically designed for Mars flight is described, emphasizing its conceivable role as an aerial surveyor for visual imaging, gamma-ray and IR reflectance spectroscopy, studies of atmospheric composition and dynamics, and gravity-field, magnetic-field, and electromagnetic sounding. Possible imaging systems and surveying tasks are considered, along with a plausible mission scenario for a fleet of 12 airplanes, which would be taken to Mars in squadrons of four by three Shuttle/IUS Twin Stage/spacecraft carriers. A basic configuration closely resembling that of a competition glider is examined, and four types of airplane are discussed: hydrazine-powered cruisers and landers and electrically powered cruisers and landers. Attention is given to navigation, guidance, and control avionics, vehicle weight, the use of composite materials for the wing, and flight testing on earth.

Clarke, V. C.↗
NASA NTRS1979

A Mars Airplane . . . Oh really

This paper describes the mission design, scientific utilization, and prototypical design of a Mars Airplane. As a scientific platform, the airplane provides an excellent means of obtaining data in a resolution range intermediate to surface vehicles and orbiters. It has great versatility to perform a variety of missions: conduct aerial surveys, land instrument packages, collect samples, and perform atmospheric sounding. The Mars Airplane has many characteristics of a competition glider on earth. Two versions of the plane, a cruiser, and one with soft landing and takeoff capability, have been designed. Maximum range and endurance are 10,000 km and 31.1 hours with a 40-kg payload.

Clarke, V. C., Jr.↗
NASA NTRS1978

Fabrication of composite shell structure for advanced space transportation

It is pointed out that future space missions, such as those involving spacecraft and structural assemblies to be used in geosynchronous orbits, will require ultralightweight composite structures to achieve maximum payloads. Of equal importance is the requirement to provide designs that are cost-competitive with metal designs. For space structures that must resist buckling, graphite-epoxy materials offer an attractive potential for providing lightweight, low-cost structural components that will meet future space mission requirements. A description is presented of a program which was conducted to evaluate the merits of graphite-epoxy cylindrical shells and to continue the development of a design data base for ultralightweight structures. An objective of the program was to design, fabricate, and test a corrugated graphite-epoxy cylinder 10 ft in diameter and 10 ft long.

Penton, A. P.↗
NASA NTRS1978

Background and system description of the Mod 1 wind turbine generator

The Mod-1 wind turbine considered is a large utility-class machine, operating in the high wind regime, which has the potential for generation of utility grade power at costs competitive with other alternative energy sources. A Mod-1 wind turbine generator (WTG) description is presented, taking into account the two variable-pitch steel blades of the rotor, the drive train, power generation/control, the Nacelle structure, and the yaw drive. The major surface elements of the WTG are the ground enclosure, the back-up battery system, the step-up transformer, elements of the data system, cabling, area lighting, and tower foundation. The final system weight (rotor, Nacelle, and tower) is expected to be about 650,000 pounds. The WTG will be capable of delivering 1800 kW to the utility grid in a wind-speed above 25 mph.

Ernst, E. H.↗
NASA NTRS1979

Space reflector technology and its system implications

The technical feasibility of providing nearly continuous solar energy to a world-distributed set of conversion sites by means of a system of orbiting, large-area, low-areal-density reflecting structures is examined. Requisite mirror area to provide a chosen, year-averaged site intensity is shown. A modeled reflector structure, with suitable planarity and ability to meet operational torques and loads, is discussed. Typical spatial and temporal insolation profiles are presented. These determine the sizing of components and the output electric power from a baselined photovoltaic conversion system. Technical and economic challenges which, if met, would allow the system to provide a large fraction of future world energy needs at costs competitive to circa-1995 fossil and nuclear sources are discussed.

Billman, K. W.↗
NASA NTRS1979

Comparison of projected critical currents in PbMo6S8 and Nb3Ge

Critical current densities, Jc, of sputtered Chevrel phase PbMo6S8 films have been measured as a function of field to 19 T at several temperatures. The pinning forces were found to obey a scaling law. Assuming an effective upper critical field Bc2 = 45 T, an effective critical temperature Tc = 13 K, together with empirical estimates of numerical factors in the scaling law, the upper limits for critical current density Jc in PbMo6S8 are estimated. Comparisons are made with estimates of Jc for Nb3Ge at 4.2 K. A crossover of Jc vs. B is found for B of the order of 25 to 30 T. Below this point, Nb3Ge is projected to have a higher critical current density. Thus practical use of Chevrel materials in high field magnets only appears to be competitive with Nb3Ge for fields above 25 to 30 T.

Alterovitz, S. A.↗
NASA NTRS1979

Do photovoltaics have a future

There is major concern as to the economic practicality of widespread terrestrial use because of the high cost of the photovoltaic arrays themselves. Based on their high efficiency, photovoltaic collectors should be one of the cheapest forms of energy generators known. Present photovoltaic panels are violating the trend of lower costs with increasing efficiency due to their reliance on expensive materials. A medium technology solution should provide electricity competitive with the existing medium to high technology energy generators such as oil, coal, gas, and nuclear fission thermal plants. Programs to reduce the cost of silicon and develop reliable thin film materials have a realistic chance of producing cost effective photovoltaic panels.

Williams, B. F.↗
NASA NTRS1979

Benefits of solar/fossil hybrid gas turbine systems

The potential benefits of solar/fossil hybrid gas turbine power systems were assessed. Both retrofit and new systems were considered from the aspects of cost of electricity, fuel conservation, operational mode, technology requirements, and fuels flexibility. Hybrid retrofit (repowering) of existing combustion (simple Brayton cycle) turbines can provide near-term fuel savings and solar experience, while new and advanced recuperated or combined cycle systems may be an attractive fuel saving and economically competitive vehicle to transition from today's gas and oil-fired powerplants to other more abundant fuels.

Bloomfield, H. S.↗
NASA NTRS1978

SOLARES - A new hope for solar energy

A system of orbiting reflectors, SOLARES, has been studied as a possible means of reducing the diurnal variation and enhancing the average intensity of sunlight with a space system of minimum mass and complexity. The key impact that such a system makes on the economic viability of solar farming and other solar applications is demonstrated. The system is compatible with incremental implementation and continual expansion to meet the world's power needs. Key technology, environmental, and economic issues and payoffs are identified. SOLARES appears to be economically superior to other advanced, and even competitive with conventional, energy systems and could be scaled to completely abate our fossil fuel usage for power generation. Development of the terrestrial solar conversion technique, optimized for this new artificial source of solar radiation, yet remains.

Billman, K. W.↗
NASA NTRS1979

Development of space manufacturing systems concepts utilizing lunar resources

Results of a NASA sponsored study to evaluate the merits of constructing solar power satellites using lunar and terrestrial resources are reviewed. Three representative lunar resources utilization (LRU) concepts were developed and compared with a previously designed earth baseline concept, and major system hardware elements as well as personnel requirements were defined. LRU for space construction was shown to be competitive with earth baseline approach for a program requiring 10 to the 5th metric tons per year of completed satellites. Results also indicated that LRU can reduce earth launched cargo requirements to less than 10% of that needed to build satellites exclusively from earth materials, with a significant percentage of the reduction due to the use of liquid oxygen derived from lunar soil. A concept using the mass driver to catapult lunar material into space was found to be superior to the other LRU logistics techniques investigated.

Bock, E. H.↗
NASA NTRS1979

A review of Curtiss-Wright rotary engine developments with respect to general aviation potential

Aviation related rotary (Wankel-type) engine tests, possible growth directions and relevant developments at Curtiss-Wright have been reviewed. Automotive rotary engines including stratified charge are described and flight test results of rotary aircraft engines are presented. The current 300 HP engine prototype shows basic durability and competitive performance potential. Recent parallel developments have separately confirmed the geometric advantages of the rotary engine for direct injected unthrottled stratified charge. Specific fuel consumption equal to or better than pre- or swirl-chamber diesels, low emission and multi-fuel capability have been shown by rig tests of similar rotary engine.

Jones, C.↗