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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 1,063 records · Page 59
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Soluble Aromatic Polyimides For Film Coating

Because of toughness, flexibility, and remarkable thermal stability, linear all-aromatic polyimides excellent candidate film and coating materials for advanced electronic circuitry and wires. Study determined effects on solubility of changing isomeric points of attachment of phenoxy units in diamine portions of several all-aromatic polyimides. Tough, flexible, transparent films produced by thermally converting polyamic acids to polyimides at 300 degree C in air. Potential for electronic applications excellent.

St. Clair, Anne K.↗
NASA NTRS1989

Polymer Coatings Reduce Electro-osmosis

Poly(ethylene glycol) film controls electrostatic potential. Electro-osmosis in quartz or glass chambers reduced or reversed by coating inside surface of chambers with monomacromolecular layers of poly(ethylene glycol). Stable over long times. Electrostatic potential across surface of untreated glass or plastic chamber used in electro-phoresis is negative and attracts cations in aqueous electrolyte. Cations solvated, entrains flow of electrolyte migrating toward cathode. Electro-osmotic flow interferes with desired electrophoresis of particles suspended in electrolyte. Polymer coats nontoxic, transparent, and neutral, advantageous for use in electrophoresis.

Herren, Blair J.↗
NASA NTRS1989

Review Of Fiber-Optic Electric-Field Sensors

Tutorial paper reviews state of art in fiber-optic sensors of alternating electric fields. Because such sensors are made entirely of dielectric materials, they are relatively transparent to incident electric fields; they do not distort fields significantly. Paper presents equations that express relationships among stress, strain, and electric field in piezoactive plastic and equations for phase shift in terms of photoelastic coefficients and strains in optical fiber.

De Paula, Ramon P.↗
NASA NTRS1989

Making MgO/SiO2 Glasses By The Sol-Gel Process

Silicon dioxide glasses containing 15 mole percent magnesium oxide prepared by sol-gel process. Not made by conventional melting because ingredients immiscible liquids. Synthesis of MgO/SiO2 glass starts with mixing of magnesium nitrate hexahydrate with silicon tetraethoxide, both in alcohol. Water added, and transparent gel forms. Subsequent processing converts gel into glass. Besides producing glasses of new composition at lower processing temperatures, sol-gel method leads to improved homogeneity and higher purity.

Bansal, Narottam P.↗
NASA NTRS1988

Observing SN 1987A with IUE

Spectra from IUE were used to study SN 1987A in order to examine its progenitor and stellar evolution before the explosion. The B3 Ia blue supergiant is identified as progenitor. The narrow UV lines from the circumstellar shell are discussed. When the supernova turns transparent in the ultraviolet, the ultraviolet spectra can provide important chemical information about the interior of the massive star.

Kirshner, Robert P.↗
NASA NTRS1988

Hitchhiker capabilities

A carrier system has been developed for economical and quick response flight of small attached payloads on the space shuttle. Hitchhiker can accommodate up to 750 lb of customer payloads in canisters or mounted to an exposed side-mount plate, or up to 1200 lb mounted on a cross-bay structure. The carrier connects to the orbiter's electrical systems and provides up to six customers with standard electrical services including power, real time telemetry and commands. A transparent data and command system concept is employed to allow the customer to easily use his own ground support equipment and personnel to control his payload during integration and flight operations. A general description of the Hitchhiker program and the Shuttle Payload of Opportunity Carrier (SPOC) is given and future enhancements are outlined.

Goldsmith, Theodore C.↗
NASA NTRS1988

Inorganic chemical precipitate formation payload design

The Get Away Special payload to investigate the formation of inorganic precipitates (G-405) utilizes six transparent chemical reaction chambers to actively mix a dry powder with a liquid solution. At predetermined intervals the progress of the precipitate formation is photographed and stored as data. The precipitate particles will also be subject to post-flight analysis. The various tasks performed during the 14 hour duration of the experiment are initiated and monitored by a custom-built digital controller. The payload is currently scheduled as a backup payload for STS-29 with a possible launch date of January, 1989.

Friedrich, Craig↗
NASA NTRS1988

Gas particle radiator

A gas particle radiator adapted to operate in a microgravity space environment having a transparent boundary which transmits energy in the infrared spectrum, and a gas particle mixture that yields high absorption and emittances are described.

Donald L Chubb↗
NASA NTRS1988

A reference standard for bidirectional reflection distribution function and bidirectional transmission distribution function measurement

A Lambertian reference standard for uniformly scattering a beam of light is constructed of a plate having a planar surface with a layer of glue disposed on the surface. An evenly packed layer of monodisperse spheres is set in the layer, and when the standard is used for bi-directional (BRDF) measurements, the spheres are coated with a layer of highly relective substance, such as gold or silver. When the standard is used for bi-directional transmittance distribution function (BTDF) measurements, the spheres are of a transparent material and are provided with a roughened surface, as by acid etching. In this case, the layer of glue is an optical cement, and the plate is of glass, with the spheres, the layer, and the plate all possessing a similar refractive index.

Witherow, William K.↗
NASA NTRS1988

A fibre optic, four channel comparative photometer

Development of a four channel comparative photometer is described. Tests have shown that it is stable from night to night and is capable of working in very poor sky conditions. Even when the sky conditions are so poor that stars are barely visible, light curves can still be obtained with an r.m.s. value of 0.0016 mag., provided that integration times that are long compared with the transparancy changes are possible.

Walker, E. N.↗
NASA NTRS1984

The USL NASA PC R and D interactive presentation development system

The Interactive Presentation Development System (IPFS) is a highly interactive system for creating, editing, and displaying video presentation sequences, e.g., for developing and presenting displays of instructional material similiar to overhead transparency or slide presentations. However, since this system is PC-based, users (instructors) can step through sequences forward or backward, focusing attention to areas of the display with special cursor pointers. Additionally, screen displays may be dynamically modified during the presentation to show assignments or to answer questions, much like a traditional blackboard. This system is now implemented at the University of Southwestern Louisiana for use within the piloting phases of the NASA contract work.

Dominick, Wayne D.↗
NASA NTRS1988

Development of an expert planning system for OSSA

This paper presents concepts related to preliminary work for the development of an expert planning system for NASA's Office for Space Science and Applications (OSSA). The expert system will function as a planner's decision aid in preparing mission plans encompassing sets of proposed OSSA space science initiatives. These plans in turn will be checked against budgetary and technical constraints and tested for constraint violations. Appropriate advice will be generated by the system for making modifications to the plans to bring them in line with the constraints. The OSSA Planning Expert System (OPES) has been designed to function as an integral part of the OSSA mission planning process. It will be able to suggest a best plan, be able to accept and check a user-suggested strawman plan, and should provide a quick response to user request and actions. OPES will be written in the C programming language and have a transparent user interface running under Windows 386 on a Compaq 386/20 machine. The system's sorted knowledge and inference procedures will model the expertise of human planners familiar with the OSSA planning domain. Given mission priorities and budget guidelines, the system first sets the launch dates for each mission. It will check to make sure that planetary launch windows and precursor mission relationships are not violated. Additional levels of constraints will then be considered, checking such things as the availability of a suitable launch vehicle, total mission launch mass required vs. the identified launch mass capability, and the total power required by the payload at its destination vs. the actual power available. System output will be in the form of Gantt charts, spreadsheet hardcopy, and other presentation quality materials detailing the resulting OSSA mission plan.

Groundwater, B.↗
NASA NTRS1986

A distributed programming environment for Ada

Despite considerable commercial exploitation of fault tolerance systems, significant and difficult research problems remain in such areas as fault detection and correction. A research project is described which constructs a distributed computing test bed for loosely coupled computers. The project is constructing a tool kit to support research into distributed control algorithms, including a distributed Ada compiler, distributed debugger, test harnesses, and environment monitors. The Ada compiler is being written in Ada and will implement distributed computing at the subsystem level. The design goal is to provide a variety of control mechanics for distributed programming while retaining total transparency at the code level.

Brennan, Peter↗
NASA NTRS1986

Experience with the CAIS

Intermetrics' experience is that the Ada package construct, which allows separation of specification and implementation allows specification of a CAIS that is transportable across varying hardware and software bases. Additionally, the CAIS is an excellent basis for providing operating system functionality to Ada applications. By allowing the Byron APSE to be moved easily from system to system, and allowing significant re-writes of underlying code. Ada and the CAIS provide portability as well as transparency to change at the application operating system interface level.

Tighe, Michael F.↗
NASA NTRS1986

A study of the use of abstract types for the representation of engineering units in integration and test applications

Physical quantities using various units of measurement can be well represented in Ada by the use of abstract types. Computation involving these quantities (electric potential, mass, volume) can also automatically invoke the computation and checking of some of the implicitly associable attributes of measurements. Quantities can be held internally in SI units, transparently to the user, with automatic conversion. Through dimensional analysis, the type of the derived quantity resulting from a computation is known, thereby allowing dynamic checks of the equations used. The impact of the possible implementation of these techniques in integration and test applications is discussed. The overhead of computing and transporting measurement attributes is weighed against the advantages gained by their use. The construction of a run time interpreter using physical quantities in equations can be aided by the dynamic equation checks provided by dimensional analysis. The effects of high levels of abstraction on the generation and maintenance of software used in integration and test applications are also discussed.

Johnson, Charles S.↗
NASA NTRS1988

Infrared spectroscopy of Jupiter and Saturn

High resolution infrared spectoscopy provides unique insights into the chemistry and dynamics of the atmospheres of Jupiter and Saturn. The 5 micrometer spectral region, which is transparent to deep levels, is particularly useful for the identification of molecules that are present at very low (parts per billion) concentrations. These are tracers of convective and strongly non-equilibrium processes in the atmosphere. High resolution ground-based spectroscopy complements Voyager and Galileo measurements. Spectroscopy is sensitive to lower mixing levels for selected molecules, while the on-board mass spectrometers probe molecules that are spectroscopically inaccessible. Analysis and modeling of the 4.7 micrometer carbon monoxide in Jupiter was completed. CO is present at a mole fraction of 1.6 plus or minus 0.3 x 10 to the 9th power and concentrated in the troposphere. At this abundance, it must be convected upward from much deeper levels in Jupiter where the temperature is near 1100 K. Thus CO is a tracer of the deep atmosphere which is otherwise unobservable. The oxygen abundance in Jupiter (as measured by the CO abundance) is near solar. Chemical or physical process must deplete the major oxygen carrier, water. Germane, GeH4, was discovered on Saturn at amole fraction of 4 plus or minus 2 x 10 to the 10th power.

Knacke, Roger↗
NASA NTRS1988

Occultation studies of the solar system

Occultations of stars by planets, satellites, planetary ring systems, asteroids, and comets provide valuable opportunities to probe the Solar System in ways otherwise impossible from the surface of the earth. For example, one can precisely measure the size and shape of objects which are much too small to be resolved directly, accurately map the structure and transparency of ring systems, and detect the faintest trace of an atmosphere. In this investigation, researchers identify upcoming occultations through wide-ranging computer searches, provide accurate predictions for the more important events, and observe selected occultations with our specially designed portable photometric equipment. During the past year, researchers produced accurate predictions for an occultation of AG+40 degrees 0783 by 324 Bamberga on 8 December 1987 and coordinated efforts to observe this event. The occultation was successfully observed at 13 sites including two manned by Lowell Observatory astronomers.

Millis, Robert L.↗
NASA NTRS1987

An investigation of ground-based observations of solar oscillations at Stanford

Data obtained in the last 8 years of solar differential Doppler observations at Stanford were considered. The four best time series of data were examined in detail. The sources of error in the data were investigated and removed where possible. In particular, the contribution resulting from transparency variations in the sky was examined. Detection method applicable to data with low signal to noise ratio and low filling factor were developed and utilized for the investigation of global solar modes of oscillations in the data. The frequencies of p-modes were measured and identified. The presence of g-modes were also determined in the Stanford data.

Henning, Harald M. J.↗