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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 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Instant-replay data system for combustion tests

A portable, inexpensive, easily programmed, and flexible pressure measuring and display system is described and evaluated in a multi-port combustion model. The data reduction system consists of a desk-top graphics display system and calculator with data tape storage and standard data communications interfacing capabilities, while a hard copy unit provides a permanent record of all plots and tables. The system offers the advantages of recording and comparing a large number of pressures at high data rates along with the display of the results in a meaningful graphical form for near real time analysis. Some discussion of combustor and engine experiments are included as examples of the data system application.

Trexler, C. A.↗
NASA NTRS1980

Protective clothing textile research for space activities in the 1980's

Textile and clothing specifications for space activities are discussed, emphasizing a chronological and utilitarian role. New fabrication techniques led to the Mercury Space Suit, a constant-wear hybrid of the omni-environmental full pressure suit used by high-flying pilots of the 1950s. The Gemini program (1964-1966) provided the first specifically designed protective clothing assembly for both intra- and extravehicular operations. The G4C, used for EV (extravehicular) activities, protected the astronaut against solar radiation, heat loss, and meteoroid penetration. The clothing for the Apollo program (1968-1975) mirrored a greater concern for fire safety with Durette (a halogenated polyamide) and PBI (polybenzimadazole) widely used for intravehicular garments. With the advent of the Shuttle program, cabin pressure and composition were changed from 6 psi, 100% oxygen to 9-14 psi, 23.4% oxygen, 76.6% N2. As a result, 'off-the-shelf' materials were used without compromising fire safety. Reusability was stressed, as textile costs and durability were now important selection criteria noting that existing textile materials will probably be adequate for the next 20 years of space operations and research. A portable lunar survival shelter made of textiles is being developed; and a preliminary design for an EV 'tunnel suit system' (an access tunnel and homoform work station) is already in existence.

Radnofsky, M. I.↗
NASA NTRS1981

High-speed photometry of the 11 December 1979 Juno occultation

The occultation of SAO 115946 by Juno on 11 December 1979 was observed from two sites in southern California with portable two-color, high-speed photometers. A composite light curve was constructed from the data by suitable scaling of individual observations, using an astrometric solution for the location of the contact points on Juno's limb. The preliminary astrometric solution used here has a semiminor axis of 118 km and a semimajor axis of 145 km at position angle 75.5 deg. The composite light curve is compatible with a stellar radius of (1.6 + or - 0.8) x 10 to the -4th arcsec, consistent with the radius estimated from the color and visual magnitude. There is no evidence for any companions to SAO 115946 or Juno. The prospects for use of asteroid occultations to determine stellar radii and asteroid surface slopes are discussed as compared with the lunar occultation technique.

Reitsema, H. J.↗
NASA NTRS1981

The mineralogy and the isotopic composition of sulfur in hydrothermal sulfide/sulfate deposits on the East Pacific Rise, 21 deg N latitude

The mineralogy and isotopic composition of sulfur found in hydrothermal deposits associated with five groups of vents along the ridge axis of the East Pacific Rise near 21 deg N latitude are investigated. Solid samples of mixed sulfides and sulfates from mounds, chimneys and the surrounding sediment as well as fresh basaltic glass were examined with a portable X-ray fluorescence spectrometer and by scanning electron microscopy, X-ray diffractometry, and electron microprobe analysis. For the three vents of exit temperature close to 350 C, the chimneys are found to be rich in copper sulfides, while for those of temperatures around 300 C, zinc sulfide is found to predominate. The major sulfides found in the chimneys include wurtzite, chalcopyrite, pyrite and cubanite, with anhydrite the dominant sulfate. Significant mineralogical differences are found between active and inactive vents. The isotopic composition of sulfur in anhydrites from active vents is observed to be close to that of sea water and consistent with a derivation from sea water sulfate. The isotopic composition of sulfur in the sulfide minerals is explained in terms of precipitation from solutions with reduced sulfur derived from basalts or basaltic magmas, and sea water sulfate. Finally, the deposits are interpreted as the results of the mixing of H2S-dominated hydrothermal fluids with cold sea water near the sea floor.

Styrt, M. M.↗
NASA NTRS1980

Integrated computer-aided design using minicomputers

Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM), a highly interactive software, has been implemented on minicomputers at the NASA Langley Research Center. CAD/CAM software integrates many formerly fragmented programs and procedures into one cohesive system; it also includes finite element modeling and analysis, and has been interfaced via a computer network to a relational data base management system and offline plotting devices on mainframe computers. The CAD/CAM software system requires interactive graphics terminals operating at a minimum of 4800 bits/sec transfer rate to a computer. The system is portable and introduces 'interactive graphics', which permits the creation and modification of models interactively. The CAD/CAM system has already produced designs for a large area space platform, a national transonic facility fan blade, and a laminar flow control wind tunnel model. Besides the design/drafting element analysis capability, CAD/CAM provides options to produce an automatic program tooling code to drive a numerically controlled (N/C) machine. Reductions in time for design, engineering, drawing, finite element modeling, and N/C machining will benefit productivity through reduced costs, fewer errors, and a wider range of configuration.

Storaasli, O. O.↗
NASA NTRS1981

An approach to real-time simulation using parallel processing

Current applications of real-time simulations to the development of complex aircraft propulsion system controls have demonstrated the need for accurate, portable, and low-cost simulators. This paper presents a preliminary simulator design that uses a parallel computer organization to provide these features. The hardware and software for this prototype simulator are discussed. A detailed discussion of the inter-computer data transfer mechanism is also presented.

Blech, R. A.↗
NASA NTRS1982

X Ray Measurement of Tank Liquid Level

Liquid surface observed through metal container wall, allowing direct determination of quantities and changes. X-ray measurement of liquid level produces photograph in which liquid appears as solid dark mass. Commercially-available portable X-ray machine is used.

Macias, R. G.↗
NASA NTRS1982

Lock for Gantry Trolley

Single operator on ground controls trolley-locking mechanism on portable gantry. Mechanism prevents trolley and load from moving along track when gantry is wheeled from one location to another. A downward pull on chain withdraws brakeshoes from trolley wheels. When operator releases chain, brakeshoes reengage to wheels.

Newberg, H. F.↗
NASA NTRS1983

Ride-Quality Meter

Single- and combined-Axis discomfort are corrected by effects of noise and vibration to yield measure of total discomfort experienced by rider. Three modules transform mathematically-weighted rms accelerations, which represent physical vibration characteristics, into subjective discomfort units. Portable "ride-quality" meter measures passenger discomfort and acceptability of vehicle interior noise and vibration. Meter especially suited for determining vehicle comfort and design tradeoffs and for comparing ride quality of vehicles.

Leatherwood, J. D.↗
NASA NTRS1983

Quick-Connect, Self-Alining Latch

Sturdy latch tolerates 10 degrees of angular mismatch in joining structural elements. Hexagonal passive plate nests in active plate, guided by capture plates and alinement keys and grooves. Center hole in both active and passive plates is 1 meter in diameter. Latch has possible uses a pipe joint, connector for parts of portable structures, and fitting for marine risers on offshore drilling rigs.

Burns, G. C.↗
NASA NTRS1983

Radionuclide Counting Technique Measures Wind Velocity

Proposed technique for measuring wind velocity based on inverse-squarelaw variation of radioactive counting rates. In proposal, radioative source is deposited on bottom of light, hollow sphere and suspended by flexible wire over radiation counter, Anemometer based on this concept is self-contained, portable, yet not too fragile. Used for extended periods of time, even at remote, inhospitable and inaccessible sites.

Singh, J. J.↗
NASA NTRS1981

Technical and economic aspects of hydrogen storage in metal hydrides

The recovery of hydrogen from such metal hydrides as LiH, MgH2, TiH2, CaH2 and FeTiH compounds is studied, with the aim of evaluating the viability of the technique for the storage of hydrogen fuel. The pressure-temperature dependence of the reactions, enthalpies of formation, the kinetics of the hydrogen absorption and desorption, and the mechanical and chemical stability of the metal hydrides are taken into account in the evaluation. Economic aspects are considered. Development of portable metal hydride hydrogen storage reservoirs is also mentioned.

Schmitt, R.↗
NASA NTRS1981

Real time software tools and methodologies

Real time systems are characterized by high speed processing and throughput as well as asynchronous event processing requirements. These requirements give rise to particular implementations of parallel or pipeline multitasking structures, of intertask or interprocess communications mechanisms, and finally of message (buffer) routing or switching mechanisms. These mechanisms or structures, along with the data structue, describe the essential character of the system. These common structural elements and mechanisms are identified, their implementation in the form of routines, tasks or macros - in other words, tools are formalized. The tools developed support or make available the following: reentrant task creation, generalized message routing techniques, generalized task structures/task families, standardized intertask communications mechanisms, and pipeline and parallel processing architectures in a multitasking environment. Tools development raise some interesting prospects in the areas of software instrumentation and software portability. These issues are discussed following the description of the tools themselves.

Christofferson, M. J.↗
NASA NTRS1981

Advanced Microwave Moisture Sounder (AMMS) for WB-57F CCOPE mission

The AMMS, flown on the WB-57F Cooperative Convective Precipitation Experiment (CCOPE), collected data at three bands on either side of the 183.3 GHz water vapor line at + or - 2.25, + or - 5.00, and + or - 8.75 GHz. Data were also collected simultaneously at a single low-loss atmospheric window channel near 94 GHz. The AMMS scanner imaged the scene below the WB-57F over an angular range of + or - 45 degree about nadir with beam-widths of 2 degree and 1 degree for the 94 GHz and 183 GHz sensors, respectively. The radiometer system operated under control of the onboard microcomputer used to: store radiometric data on the AMMS flight recorder, operate the stepper motor driven scanner, and collect pertinent housekeeping data for the system. A portable ground support system was used following each CCOPE flight to provide quick-look data analysis. The CCOPE flight logs and tape of the AMMS data were delivered to NASA.

Gagliano, J. A.↗
NASA NTRS1981

Acoustic ground impedance meter

A compact, portable instrument was developed to measure the acoustic impedance of the ground, or other surfaces, by direct pressure-volume velocity measurement. A Helmholz resonator, constructed of heavy-walled stainless steel but open at the bottom, is positioned over the surface having the unknown impedance. The sound source, a cam-driven piston of known stroke and thus known volume velocity, is located in the neck of the resonator. The cam speed is a variable up to a maximum 3600 rpm. The sound pressure at the test surface is measured by means of a microphone flush-mounted in the wall of the chamber. An optical monitor of the piston displacement permits measurement of the phase angle between the volume velocity and the sound pressure, from which the real and imaginary parts of the impedance can be evaluated. Measurements using a 5-lobed cam can be made up to 300 Hz. Detailed design criteria and results on a soil sample are presented.

Zuckerwar, A. J.↗
NASA NTRS1982

User's guide to noise data acquisition and analysis programs for HP9845: Nicolet analyzers

A software interface package was written for use with a desktop computer and two models of single channel Fast Fourier analyzers. This software features a portable measurement and analysis system with several options. Two types of interface hardware can alternately be used in conjunction with the software. Either an IEEE-488 Bus interface or a 16-bit parallel system may be used. Two types of storage medium, either tape cartridge or floppy disc can be used with the software. Five types of data may be stored, plotted, and/or printed. The data types include time histories, narrow band power spectra, and narrow band, one-third octave band, or octave band sound pressure level. The data acquisition programming includes a front panel remote control option for the FFT analyzers. Data analysis options include choice of line type and pen color for plotting.

Mcgary, M. C.↗
NASA NTRS1982

High accuracy OMEGA timekeeping

The Smithsonian Astrophysical Observatory (SAO) operates a worldwide satellite tracking network which uses a combination of OMEGA as a frequency reference, dual timing channels, and portable clock comparisons to maintain accurate epoch time. Propagational charts from the U.S. Coast Guard OMEGA monitor program minimize diurnal and seasonal effects. Daily phase value publications of the U.S. Naval Observatory provide corrections to the field collected timing data to produce an averaged time line comprised of straight line segments called a time history file (station clock minus UTC). Depending upon clock location, reduced time data accuracies of between two and eight microseconds are typical.

Imbier, E. A.↗
NASA NTRS1982

Comparison of VLBI, TV and traveling clock techniques for time transfer

A three part experiment was conducted to develop and compare time transfer techniques. The experiment consisted of (1) a very long baseline interferometer (VLBI), (2) a high precision portable clock time transfer system between the two sites, and (3) a television time transfer. A comparison of the VLBI and traveling clock shows each technique can perform satisfactorily at the five nsec level. There was a systematic offset of 59 nsec between the two methods, which we attributed to a difference in epochs between VLBI formatter and station clock. The VLBI method had an internal random error of one nsec at the three sigma level for a two day period. Thus, the Mark II system performed well, and VLBI shows promise of being an accurate method of time transfer. The TV system, which had technical problems during the experiment, transferred time with a random error of about 50 nsec.

Spencer, J. H.↗