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At least 451 records · Page 25

The ILLIAC IV memory system: Current status and future possibilities

The future needs of researchers who will use the Illiac were examined and the requirements they will place on the memory system were evaluated. Various alternatives to replacing critical memory components were considered with regard to cost, risk, system impact, software requirements, and implementation schedules. The current system, its performance and status, and the limitations it places on possible enhancements are discussed as well as the planned enhancements to the Illiac processor. After a brief technology survey, different implementations are presented for each system memory component. Three different memory systems are proposed to meet the identified needs of the Illiac user community. These three alternatives differ considerably with respect to storage capacity and accessing capabilities, but they all offer significant improvements over the current system. The proposed systems and their relative merits are analyzed.

Stevenson, D. K.↗

Results and status of the NASA aircraft engine emission reduction technology programs

The results of an aircraft engine emission reduction study are reviewed in detail. The capability of combustor concepts to produce significantly lower levels of exhaust emissions than present production combustors was evaluated. The development status of each combustor concept is discussed relative to its potential for implementation in aircraft engines. Also, the ability of these combustor concepts to achieve proposed NME and NCE EPA standards is discussed.

Jones, R. E.↗

Technology status: Batteries and fuel cells

The current status of research and development programs on batteries and fuel cells and the technology goals being pursued are discussed. Emphasis is placed upon those technologies relevant to earth orbital electric energy storage applications.

Fordyce, J. S.↗

Technology Status: Fuel Cells and Electrolysis Cells

The status of the baselined shuttle fuel cell as well as the acid membrane fuel cell and space-oriented water electrolysis technologies are presented. The more recent advances in the alkaline fuel cell technology area are the subject of a companion paper. A preliminary plan for the focusing of these technologies towards regenerative energy storage applications in the multi-hundred kilowatt range is also discussed.

Mcbryar, H.↗

Status review of PMR polyimides

The current status of first and second generation PMR polyimides are reviewed. Synthesis, processing, and applications were considered, using prepreg materials based on processable, high temperature resistant polyimides.

Serafini, T. T.↗

Present status of GaAs

An extensive literature survey on GaAs was carried out for the period December 31, 1970, to December 31, 1977. The increasing interest in GaAs device structures increased steadily during that period. The leading research and development centers and the specific areas of interest were identified. A workshop on GaAs was held in November 1977 to assess the present status of melt-grown GaAs and the existing needs for reliable chemical, structural, and electronic characterization methods. It was concluded that the present available bulk GaAs crystals are of poor quality and that GaAs technology is lagging demonstrated or potentially feasible GaAs devices and systems.

Gatos, H. C.↗

The advanced low-emissions catalytic-combuster program. Phase 1: Description and status

An overview of the ongoing program is presented. Objectives, plan, schedule, pollution and performance goals, catalyst advantages, present problems, and the present status of identified combustor concepts are discussed. The possible increase in upper atmosphere oxides of nitrogen (NOx) levels due to aircraft number density increases was predicted to adversely decrease ozone concentration levels. A technique for achieving low NOx emission levels was experimentally demonstrated with a lean, premixing prevaporizing flame-tube combustor.

Szaniszlo, A. J.↗

Status and prospects of computational fluid dynamics

The use and limitations on using computational aerodynamics in approximating inviscid linear, inviscid nonlinear, vicous time averaged, and viscous time dependent flow past airfoils, wings, and aircraft is reviewed. The current status of two- and three-dimensional time averaged Navier-Stokes equation is discussed and possible applications for the 1980 and 1985 to 1990 period is projected for three-dimensional applications.

Chapman, D. R.↗

Review and status of liquid-cooling technology for gas turbines

A review was conducted of liquid-cooled turbine technology. Selected liquid-cooled systems and methods are presented along with an assessment of the current technology status and requirements. A comprehensive bibliography is presented.

Vanfossen, G. J., Jr.↗

Systems identification and application systems development for monitoring the physiological and health status of crewmen in space

The use of automated, analytical techniques to aid medical support teams is suggested. Recommendations are presented for characterizing crew health in terms of: (1) wholebody function including physiological, psychological and performance factors; (2) a combination of critical performance indexes which consist of multiple factors of measurable parameters; (3) specific responses to low noise level stress tests; and (4) probabilities of future performance based on present and periodic examination of past performance. A concept is proposed for a computerized real time biomedical monitoring and health care system that would have the capability to integrate monitored data, detect off-nominal conditions based on current knowledge of spaceflight responses, predict future health status, and assist in diagnosis and alternative therapies. Mathematical models could play an important role in this approach, especially when operating in a real time mode. Recommendations are presented to update the present health monitoring systems in terms of recent advances in computer technology and biomedical monitoring systems.

Leonard, J. I.↗

Status of NO sub x control for coal-fired power plants

The status of technologies for controlling emissions of oxides of nitrogen (NOx) from coal-fired power plants is reviewed. A discussion of current technology as well as future NOx control approaches is presented. Advanced combustion approaches are included as well as post-combustion alternatives such as catalytic and noncatalytic ammonia-bases systems and wet scrubbing. Special emphasis is given to unresolved development issues as they relate to practical applications on coal-fired power plants.

Teixeira, D. P.↗

Status of candidate materials for full-scale tests in the 737 fuselage

The test program has the objectives to: (1) increase passenger evacuation time to a minimum of five minutes from commercial aircraft in case of a fire; (2) prevent an external fire from entering closed cabins for five minutes by using fire barrier materials in the exterior wall; (3) demonstrate that a closed cabin will not reach 400 F; and (4) prove that a fire near a cabin opening will not propagate through the cabin for a minimum of five minutes. The materials status is outlined for seat cushions, upholstery and associated seat materials, wall and ceiling panels, floor panels, carpet and carpet underlay, windows, cargo bay liners, insulation bagging, and thermal acoustical insulation.

Supkis, D.↗

First Spacelab flight - A status report of the joint ESA/NASA mission

A general overview of the first Spacelab flight is presented and a table is given listing the payload composition. An accommodation study is presented with emphasis on the configuration, mass status, timeline, and experiment interface specifications. Also considered are flight and ground operations, safety factors, and payload specialists training for the first flight.

Craft, H. G., Jr.↗

Status and summary of laser energy conversion

This paper presents a survey of the status of laser energy converters. Since the inception of these devices in the early 1970's, significant advances have been made in understanding the basic conversion processes. Numerous theoretical and experimental studies have indicated that laser energy can be converted at wavelengths from the ultraviolet to the far-infrared. These converters can be classified into five general categories: photovoltaics, heat engines, thermoelectronic, optical diode, and photochemical. The conversion can be directly into electricity (such as the photovoltaic, thermoelectronic, and optical diode) or it can go through an intermediate stage of conversion to mechanical energy, as in the heat engines. The photochemical converters result in storable energy such as hydrogen. Projected conversion efficiencies range from about 30% for the photochemical to nearly 75% for the heat engines.

Lee, G.↗

Space Shuttle Program description and status

The main reason for the development of the Space Shuttle is related to the aim to achieve a major reduction in the cost of placing a payload into space. Such a reduction is to be obtained by using a reusable in place of an expendable launch vehicle. Developments concerning launch vehicles show a steady reduction in launching expenses. From a cost of about $500,000 a pound in the late 1950's, launching expenses were reduced to $600 a pound for payloads on the Saturn V. With the Space Shuttle the cost will drop to approximately $150 a pound. The Space Shuttle Program is discussed, taking into account a system description, a typical mission profile, aspects of mission design, launch costs, and Space Shuttle characteristics. The Space Shuttle Program status is also examined, giving attention to orbital flight schedules, flight hardware tests, launch area facilities, the mission control center, and details of flight crew training.

Macleod, J. B.↗

Prop-fan propulsion - Its status and potential

Studies have established that advanced turboprop (prop-fan) equipped aircraft will reduce fuel consumption by 15 to 30 percent compared to aircraft equipped with high-bypass turbofan engines of equivalent technology. A reduction in direct operating costs of approximately 10 percent has been identified for commercial aircraft as well as approximately 20 percent lower gross weight airplane for long endurance military missions. The prop-fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficiency program which includes both analytical studies and experimental tests. The experimental work encompasses performance and acoustic wind tunnel tests on several prop-fan models. The prop-fan technology status is reviewed in the major areas of performance, installed effects, cabin noise, blade structure and maintenance cost. Also, further activities required to complete the technical validation of prop-fans are described.

Dugan, J. F., Jr.↗

Status review of PMR polyimides

In the NASA developed PMR (polymerization of monomer reactants) the reinforcing fibers are impregnated with a solution containing a mixture of monomers dissolved in a low boiling point alkyl alcohol solvent, with the monomers reacting in situ at elevated temperatures to form a thermo-oxidatively stable polyimide matrix. The current status of first and second generation PMR polyimides is reviewed, considering synthesis and properties, processing, and applications. It is concluded that the PMR approach offers various significant advantages, especially superior high temperature properties and processing versatility, to fabricators and users of polyimide/fiber composites.

Serafini, T. T.↗

Description and status of NASA-LeRC/DOE photovoltaic applications systems experiments

In its role of supporting the DOE Photovoltaic Program, the NASA-Lewis Research Center has designed, fabricated and installed 16 geographically dispersed photovoltaic systems. These systems are powering a refrigerator, highway warning sign, forest lookout towers, remote weather stations, a water chiller at a visitor center, and insect survey traps. Each of these systems is described in terms of load requirements, solar array and battery size, and instrumentation and controls. Operational experience is described and present status is given for each system. The P/V power systems have proven to be highly reliable with almost no problems with modules and very few problems overall

Ratajczak, A. F.↗