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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Portable inference engine: An extended CLIPS for real-time production systems

The present C-Language Integrated Production System (CLIPS) architecture has not been optimized to deal with the constraints of real-time production systems. Matching in CLIPS is based on the Rete Net algorithm, whose assumption of working memory stability might fail to be satisfied in a system subject to real-time dataflow. Further, the CLIPS forward-chaining control mechanism with a predefined conflict resultion strategy may not effectively focus the system's attention on situation-dependent current priorties, or appropriately address different kinds of knowledge which might appear in a given application. Portable Inference Engine (PIE) is a production system architecture based on CLIPS which attempts to create a more general tool while addressing the problems of real-time expert systems. Features of the PIE design include a modular knowledge base, a modified Rete Net algorithm, a bi-directional control strategy, and multiple user-defined conflict resolution strategies. Problems associated with real-time applications are analyzed and an explanation is given for how the PIE architecture addresses these problems.

Le, Thach↗
NASA NTRS1988

Evaluation of the Portable Instantaneous Display Analysis Spectrometer (PIDAS)

The Portable Instantaneous Display Analysis System (PIDAS) was evaluated by measuring 125 spectra of mineral specimens and rock samples under the following conditions: in the laboratory under artificial illumination and outdoors, on the building patio, while still using the line voltage electric power supplies. The PIDAS was compared and contrasted with the GEOSCAN PFS, Daedalus-Spectrafax 440, and the Geophysical Environmental Research (GER) IRIS Mark 4.

Lyon, R. J. P.↗
NASA NTRS1990

Portable High-Frequency Data-Acquisition System

Compact unit made of readily available solid-state components. Proposed system for acquisition of rapidly changing data self-contained and portable. Conceived for monitoring such aerodynamic effects as flutter, vibration, shock, sound, and pressure. Offers precise and fast acquisition of data and large data-storage capacity: has maximum sampling rate of 125 kHz, access time of 15 ns, and 1-million-bit memory. Measures time with "smart" (microprocessor-controlled) watch that maintains calendar time for more than 10 years without external power. Provides standby power from "smart" battery furnishing up to 1 ampere-hour of charge if power from main batteries lost.

Mustain, Roy W.↗
NASA NTRS1990

Force user's manual: A portable, parallel FORTRAN

The use of Force, a parallel, portable FORTRAN on shared memory parallel computers is described. Force simplifies writing code for parallel computers and, once the parallel code is written, it is easily ported to computers on which Force is installed. Although Force is nearly the same for all computers, specific details are included for the Cray-2, Cray-YMP, Convex 220, Flex/32, Encore, Sequent, Alliant computers on which it is installed.

Jordan, Harry F.↗
NASA NTRS1989

Portable digital pressure indicator for calibrating magnetic tape recorders

The design of a portable Digital Pressure Indicator (DPI) to be used for calibrating the pressure systems on Langley's magnetic tape recorders is described. High-speed magnetic tape recorders require pressure (0 to 20 psig) for providing an air cushion across the tape guides and a slight vacuum (30 inch H2O) for maintaining the proper number of tape loops in the advance and feed chamber. The DPI is a hand-held device that can be quickly coupled to a magnetic tape recorder and includes a two-position switch for selecting either measured pressure or vacuum, to be displayed digitally in engineering units (psig or inches H2O). The DPI is currently in use in Langley's Analysis and Computation Division.

Mccormick, Royce F.↗
NASA NTRS1989

Portable Dextrous Force Feedback Master for robot telemanipulation (PDMFF)

A major drawback of open loop masters is a lack of force feedback, limiting their ability to perform complex tasks such as assembly and repair. Researchers present a simple dextrous force feedback master for computer assisted telemanipulation. The device is compact, portable and can be held in the operator hand, without the need for a special joystick or console. The system is capable of both position feed forward and force feedback, using electronic position sensors and a pneumatic micro-actuator. The level of forces exercised by the pneumatic actuator is such that near rigidity may be attained. Experimental results showing good system linearity and small time lag are given.

Burdea, Grigore C.↗
NASA NTRS1989

Metal oxide regenerable carbon dioxide removal system for an advanced portable life support system

The development of a CO2 removal system for an astronaut portable life support system to meet the EVA requirements for the Space Station is discussed, focusing on the factors important in the selection of the metal oxide absorbent for CO2 removal. Results from laboratory tests on metal oxide absorbent materials are given, including characterization studies and dynamic CO2 uptake and regeneration measurements. The preliminary design of the breadboard system to perform both the absorption and regeneration functions is presented.

Nacheff, Maurena S.↗
NASA NTRS1990

Characterization of metal oxide absorbents for regenerative carbon dioxide and water vapor removal for advanced portable life support systems

Characterization of the performance of a silver-oxide-based absorbent in terms of its ability to remove both gaseous CO2 and water vapor in an astronaut portable life support systems (PLSS) is discussed. Attention is focused on regeneration of the absorbent from the carbonite state of the oxide state, preconditioning of the absorbent using a humidified gas stream, and absorption breakthrough testing. Based on the results of bench-scale experiments, a test plan is carried out to further characterize the silver-oxide-based absorbent on a larger scale; it calls for examination of the absorbent in both an adiabatic packed bed and a near-isothermal cooled bed configuration. It is demonstrated that the tested absorbent can be utilized in a way that removes substantial amounts of CO2 and water vapor during an 8-hour extravehicular activity mission, and that applying the absorbent to PLSS applications can simplify the ventilation loop.

Kast, Timothy P.↗
NASA NTRS1991

Portable Water-Saving Shower For Emergencies

Stowable compact unit sprays from many directions. Proposed portable emergency fogging shower rinses harmful chemicals from person. Includes double-walled transparent, approximately cylindrical curtain containing sets of interior nozzles on regularly spaced loops. Sealed at top and bottom. Victim of contamination enters through longitudinal zippered opening. Pressurized mixture of air and water flows through selected nozzles, creating foglike spray scrubbing contaminants from skin and clothing. Intended for use on Space Station, also used in laboratories and factories on Earth, or for routine shower bathing in areas with limited water supplies.

Grenier, Francis E.↗
NASA NTRS1990

A study of the portability of an Ada system in the software engineering laboratory (SEL)

A particular porting effort is discussed, and various statistics on analyzing the portability of Ada and the total staff months (overall and by phase) required to accomplish the rehost, are given. This effort is compared to past experiments on the rehosting of FORTRAN systems. The discussion includes an analysis of the types of errors encountered during the rehosting, the changes required to rehost the system, experiences with the Alsys IBM Ada compiler, the impediments encountered, and the lessons learned during this study.

Jun, Linda O.↗
NASA NTRS1991

A portable Ka-band front-end test package for beam-waveguide antenna performance evaluation. Part 1: Design and ground tests

A unique experimental method was used to test the beam waveguide (BWG) antenna at Deep Space Station (DDS) 13 in the Goldstone Deep Space Communications Complex near Barstow, California. The methodology involved the use of portable test packages to make measurements of operating noise temperatures and antenna efficiencies (as functions of antenna pointing angles) at the Cassegrain focal point and the final focal point located in a subterranean pedestal room. Degradations caused by the BWG mirror systems were determined by making comparisons of the measured parameters at the two focal points of the antenna. Previous articles were concerned with the design, performance characteristics, and test results obtained with an X-band test package operating at 32 GHz. Noise temperature measurement results are presented for the Ka-band test package in an on-the-ground test configuration.

Otoshi, T. Y.↗
NASA NTRS1992

Portable Power And Digital-Communication Units

Conceptual network of electronic-equipment modules provides electrical power and digital radio communications at multiple sites not served by cables. System includes central communication unit and portable units powered by solar photovoltaic arrays. Useful to serve equipment that must be set up quickly at remote sites or buildings that cannot be modified to provide cable connections.

Levin, Richard R.↗
NASA NTRS1991

The microassay on a card: A rugged, portable immunoassay

The Microassay on a Card (MAC) is a portable, hand-held, non-instrumental immunoassay that can test for the presence of a wide variety of substances in the environment. The MAC is a simple device to use. A drop of test solution is placed on one side of the card and within five minutes a color is developed on the other side in proportion to the amount of substance in the test solution, with sensitivity approaching 10 ng/ml. The MAC is self-contained and self-timed; no reagents or timing is necessary. The MAC may be configured with multiple wells to provide simultaneous testing for multiple species. As envisioned, the MAC will be employed first as an on-site screen for drugs of abuse in urine or saliva. If the MAC can be used as a screen of saliva for drugs of abuse, it could be applied to driving while intoxicated, use of drugs on the job, or testing of the identity of seized materials. With appropriate modifications, the MAC also could be used to test for environmental toxins or pollutants.

Kidwell, David↗
NASA NTRS1991

Metal oxide absorbents for regenerative carbon dioxide and water vapor removal for advanced portable life support systems

Recent studies of Allied Signal metal oxide based absorbents demonstrated that these absorbents offer a unique capability to regeneratively remove both metabolic carbon dioxide and water vapor from breathing air; previously, metal oxides were considered only for the removal of CO2. The concurrent removal of CO2 and H2O vapor can simplify the astronaut Portable Life Support System (PLSS) by combining the CO2 and humidity control functions into one regenerative component. The use of metal oxide absorbents for removal of both CO2 ad H2O vapor in the PLSS is the focus of an ongoing program. The full scale Metal Oxide Carbon dioxide and Humidity Remover (MOCHR) and regeneration unit is described.

Hart, Joan M.↗
NASA NTRS1992

Portable dynamic fundus instrument

A portable diagnostic image analysis instrument is disclosed for retinal funduscopy in which an eye fundus image is optically processed by a lens system to a charge coupled device (CCD) which produces recordable and viewable output data and is simultaneously viewable on an electronic view finder. The fundus image is processed to develop a representation of the vessel or vessels from the output data.

Taylor, Gerald R.↗
NASA NTRS1991

Direct broadcast satellite-radio: Portable and mobile reception trade-offs

There has been considerable international effort in the areas of system studies, system development, and regulatory work for a Direct Broadcast Satellite Radio (DBS-R). An important milestone will be the 1992 World Radio Administrative Conference (WARC 1992) consideration of frequency allocation in the 500 - 3000 MHz range for such a service. There is an interagency agreement between Voice of America and the National Aeronautics and Space Administration for a coordinated program in DBS-R. This program includes seven tasks: systems tradeoff studies, propagation measurements, satellite experiment and demonstration, receiver development, market studies, regulatory studies, and WARC preparations. The findings of ongoing work under the first task, systems tradeoff studies, are discussed. Topics covered include digital bit rate and audio quality, propagation considerations and link margin estimates for portable reception, link margin estimates for mobile reception, coverage, and satellite size and cost estimates for a regional DBS-R coverage example.

Golshan, Nasser↗
NASA NTRS1992

A portable lidar using a diode-pumped YAG laser

A Mie lidar system is technically established and is used for monitoring air pollution, stratospheric and boundary layer aerosol distribution, plume dispersion, visibility, and the study of atmospheric structure and cloud physics. However, a lidar system is not widely used because of its cumbersome handling and unwieldy portability. Although the author developed a laser diode lidar system based on RM-CW technique, it has a limit of measurement distance. Here we report the development of an all solid Mie lidar system using a diode-pumped Nd:YAG laser and a Si-APD detector. This was constructed as a prototype of a handy lidar system.

Takeuchi, N.↗
NASA NTRS1991

Development of a miniaturized, light-weight magnetic sector for a field-portable mass spectrograph

A miniaturized, lightweight magnetic sector for a focal plane mass spectrograph (Mattauch-Herzog design) has been designed and fabricated by using a new high-energy-product magnet material (Nd-B-Fe alloy) and a high permeability magnet yoke material (V-Co-Fe alloy). The magnetic sector weighs less than 10 kg, has a focal plane of 5.1 cm in length, and covers a nominal mass range of 40-240 amu. Such a magnetic sector, in conjunction with an array detector and a short microbore capillary column, is well suited for the development of a field-portable gas chromatograph-mass spectrometer instrument of high performance.

Sinha, M. P.↗