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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 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Digital Instrumentation Analysis and Navigation System (DIANS) for system identification

Hardware, software, and performance features of the Digital Instrumentation and Navigation System (DIANS) designed for NASA research to collect flight data as a strap-down system are detailed. The support software for the system has a cross compiler, a linkage editor, and cross assembler, extended communication capabilities, postflight processing applications, and compilers for PASCAL, FORTRAN, CBASIC and MT. The DIANS microcomputer has a 1 Mbyte RAM module, a fast floating point processor board, a 68000 monoboard computer with 64 RAM, a 128 Kbyte bubble memory card, and a navigation radio. The system also carries a battery for full system operation for over an hour. The support software is also stored on a host mainframe computer, which has a CP/M operating system. Pitch, roll, and heading data are gathered from the on-board system, and communication is possible between the airborne and ground-based computer.

Smyth, R. K.↗
NASA NTRS1983

Thermal oxidative degradation reactions of perfluoroalklethers

The objective of this contract was to investigate the mechanisms operative in thermal and thermal oxidative degradation of Fomblin Z and hexafluoropropene oxide derived fluids and the effect of alloys and additives upon these processes. The nature of arrangements responsible for the inherent thermal oxidative instability of the Fomblin Z fluids has not been established. It was determined that this behavior was not associated with hydrogen end-groups or peroxy linkages. The degradation rate of these fluids at elevated temperatures in oxidizing atmospheres was found to be dependent on the surface/volume ratio. Once a limiting ratio was reached, a steady rate appeared to be attained. Based on elemental analysis and oxygen consumption data, -CF2OCF2CF2O-, not -CF2CF2O-, is one of the major arrangements present. The action of the M-50 and Ti(4 Al, 4 Mn) alloys was found to be much more drastic in the case of Fomblin Z fluids than that observed for the hexalfuoropropane oxide derived materials. The effectiveness of antioxidation/anticorrosion additives, P-3 and phospha-s-triazine, in the presence of metal alloys was very limited at 316 C; at 288 C the additives arrested almost completely the fluid degradation. The phospha-s-triazine appeared to be at least twice as effective as the P-3 compound; it also protected the coupon better. The Ti(4 Al, 4 Mn) alloy degraded the fluid mainly by chain scission processes; this took place to a much lesser degree with M-50.

Paciorek, K. L.↗
NASA NTRS1983

A cryocooler for applications requiring low magnetic and mechanical interference

A very low-power, low-interference Stirling cryocooler is being developed based on principles and techniques described in several previous publications over the last four years. It differs in several important details from those built previously. It uses a tapered displacer based upon an analytical optimization procedure. The displacer is driven by an auxiliary piston and cylinder (rather than by mechanical linkage) using some of the working fluid itself to provide the driving force. This provides smooth, vibration-free motion, and, more importantly, allows complete mechanical and spatial separation of the cryostat from the pressure-wave generator. Either of two different pressure-wave generators can be used. One is a non-contaminating, unlubricated ceramic piston and cylinder. The other is a compressed-air-operated rubber diaphragm with motor-driven valves to cycle the pressure between appropriate limits.

Zimmerman, J. E.↗
NASA NTRS1984

Operating system for a real-time multiprocessor propulsion system simulator

The success of the Real Time Multiprocessor Operating System (RTMPOS) in the development and evaluation of experimental hardware and software systems for real time interactive simulation of air breathing propulsion systems was evaluated. The Real Time Multiprocessor Operating System (RTMPOS) provides the user with a versatile, interactive means for loading, running, debugging and obtaining results from a multiprocessor based simulator. A front end processor (FEP) serves as the simulator controller and interface between the user and the simulator. These functions are facilitated by the RTMPOS which resides on the FEP. The RTMPOS acts in conjunction with the FEP's manufacturer supplied disk operating system that provides typical utilities like an assembler, linkage editor, text editor, file handling services, etc. Once a simulation is formulated, the RTMPOS provides for engineering level, run time operations such as loading, modifying and specifying computation flow of programs, simulator mode control, data handling and run time monitoring. Run time monitoring is a powerful feature of RTMPOS that allows the user to record all actions taken during a simulation session and to receive advisories from the simulator via the FEP. The RTMPOS is programmed mainly in PASCAL along with some assembly language routines. The RTMPOS software is easily modified to be applicable to hardware from different manufacturers.

Cole, G. L.↗
NASA NTRS1984

Inherent Problems in Designing Two-Failure Tolerant Electromechanical Actuators

An electromechanical ac-powered rotary actuated four-bar linkage system for rotating the Shuttle/Centaur deployment adapter is described. The essential features of the deployment adapter rotation system (DARS) are increased reliability for mission success and maximum practical hazard control for safety. The requirements, concept development, hardware configuration, quality assurance provisions, and techniques used to meet two-fault tolerance requirements are highlighted. The rationale used to achieve a degree of safety equivalent of that of two-failure tolerance is presented. Conditions that make this approach acceptable, including single failure point components with regard to redundancy versus credibility of failure modes, are also discussed.

Hornyak, S.↗
NASA NTRS1984

Nucleic acids, proteins, and chirality

The present investigation is concerned with experimental results related, in one case, to the chirality of nucleotides, and, in another case, to the possibility of a link between the chirality of nucleic acids, and that of peptides. It has been found that aminoacylation of the 'internal' hydroxyl group of a dinucleoside monophosphate can occur stereoselectively. However, this reaction has not yet been made a part of a working peptide synthesis scheme. The formation and cleavage of oligonucleotides is considered. In the event of the formation of a helical complex between the oligonucleotide and the polymer, 1-prime,5-prime-bonds in the oligomer are found to become more resistant towards cleavage. The conditions required for peptide bond formation are examined, taking into account the known structures of RNA and possible mechanisms for prebiotic peptide bond formation. The possibility is considered that the 2-prime,5-prime-internucleotide linkage could have played an important part in the early days of biological peptide synthesis.

Usher, D. A.↗
NASA NTRS1984

An evaluation and force gradient determination of mechanically linked reversible sidestick controllers for General Aviation aircraft

In connection with the increase in air traffic, IFR (Instrument Flight Rules) flight in the air traffic control system has become very demanding. It has, therefore, become imperative to optimize the pilot's skills in his management of the various aircraft systems. The present investigation is concerned with the human factors aspects of the use of sidesticks in direct mechanical linkage (reversible) control systems in a production General Aviation (G.A.) aircraft. A total of 140 fifteen to twenty minute flight tasks were flown on the NASA Langley G.A. motion base simulator. The study involved a comparison of three locations of the sidestick, left side, center, and right side, and the standard yoke. It was found that the sidestick is preferable to the standard yoke. However, some of the design and installation features of the sidestick are critical for pilot acceptance.

Bergeron, H. P.↗
NASA NTRS1983

Modes of inter-hemispheric wave propagation

Attention is given to observations made in connection with the First GARP (Global Atmospheric Research Program) Global Experiment (FGGE), taking into account the average 200 mb zonal wind for two periods during the First Special Observing Period of FGGE, and the 200 mb velocity potential. The meridional linkages implied in the observations involve sources south of 15 deg N, and the most active extratropical patterns are collocated with regions of tropical easterlies. The possibility is investigated that the theory of reduced Rossby wave propagation through easterlies is not sufficiently general to cover the considered observations, taking into account a shallow water model. It is found that the meridional interactions cannot be associated with Rossby waves because these waves connot be generated in the regions of zero absolute vorticity gradient within which the forcing is embedded.

Paegle, J.↗
NASA NTRS1983

The new standard spacecraft timecode

Time is an important parameter for space-acquired measurements, in virtue of the basing of instrument analysis on a sampled sensor time series. In addition, time provides the most efficient linkage between instrument data and externally generated ancillary parameters. Attention is presently given to the rationale and form of the standard timecode structure developed by NASA, with emphasis on the important class of binary unsegmented codes. The structure provides a mechanism for the self-documentation of timecodes, so that data users can interpret time measurement in an unambiguous manner. The binary unsegmented codes are modular and easily machine-readable; they also feature expendable resolution and ambiguity periods.

Connell, E. B.↗
NASA NTRS1986

Synthesis of Metal Phthalocyanine Sheet Polymers

New method for synthesizing metal phthalocyanine tetracarboxylic acids (MPTCA's) yields high purity end product. In addition, high-purity metal phthalocyanine sheet polymers synthesized from compounds. Monomer formed into sheet polymer by heating. Units of polymer linked in manner similar to phenyl-group linkages in biphenyl: Conjugation extends throughout macromolecule, thereby increasing delocalization of TT-electrons. Increases conductivity and thermal stability of polymer.

Achar, B. N.↗
NASA NTRS1986

Bistable Articulated Joint

Joint with four-bar-linkage geometry has following attributes: Springs to fully extended fully folded positions. Automatically locks in its extended position. Joint combines zero backlash, positive locking, and centerline pivoting. Used in folding tool handles, portable antenna booms, and many other deployable structures.

Graighead, Norwood D., II↗
NASA NTRS1986

Latch for Telescoping Structures

Latch for three-member telescoping column developed for deployment of antenna 122 meters in diameter. Deployable column along axis of antenna open lattice structure with three longerons as principal loadbearing members. Column divided into telescoping sections that deploy, one section at time. Latch automatically locks sections into position during deployment and unlocks them when antenna restowed. Latch is four-bar linkage using over-center principle for locking, with Belleville spring washers to absorb deflections.

Ahl, Elvin L., Jr.↗
NASA NTRS1984

Second Sailplane Project: The RP-2

Progress has been made on the design fabrication and installation of a tension carry-through linkage between the aft parts of the port and starboard wings to resist forward bending deflection on the RP-2 sailplane. In addition, towhook/release mechanisms, landing gear and wheel brake assembly, compound curved sandwich composite fuselage shells and an enclosed trailer to house and transport the complete disassembled aircraft, have all undergone various stages of design, fabrication, installation and testing.

Source record↗
NASA NTRS1983

A study of the Armstrong Whitworth swing beam engine for automotive application

The introduction of ceramics to those parts suffering high thermal loading was successfully demonstrated, and there is no question that the 100 kw (134 hp) naturally aspirated engine of the future will be developed to produce up to 300 kw (402 hp) by the application of turbocharging or its equivalent. However, at the 60 - 80 kw (80 - 107 hp) size needed for the economic automotive engine, scaling down the 300 kw (402 hp) is beset by the laws of scale. The conventional four stroke diesel was not shown to be successful at the small high speed engine size. The opposed piston two stroke engine does not suffer the same laws of scale and engines in the low power range have already been marketed successfully. The half liter/cylinder Armstrong Whitworth Swing Beam Engine is the latest to be designed with the automotive market in mind. Its low noise structure and balanced linkage system coupled with advantages for easy start and potential use of low grade fuels, derived from its variable compression ratio and slow piston motion, qualifies it for the application.

Source record↗
NASA NTRS1984

Modeling long-term changes in forested landscapes and their relation to the Earth's energy balance

The dynamics of the forested parts of the Earth's surface on time scales from decades to centuries are discussed. A set of computer models developed at Oak Ridge National Laboratory and elsewhere are applied as tools. These models simulate a landscape by duplicating the dynamics of growth, death and birth of each tree living on a 0.10 ha element of the landscape. This spatial unit is generally referred to as a gap in the case of the forest models. The models were tested against and applied to a diverse array of forests and appear to provide a reasonable representation for investigating forest-cover dynamics. Because of the climate linkage, one important test is the reconstruction of paleo-landscapes. Detailed reconstructions of changes in vegetation in response to changes in climate are crucial to understanding the association of the Earth's vegetation and climate and the response of the vegetation to climate change.

Shugart, H. H.↗
NASA NTRS1985

Development of large wind energy power generation system

The background and development of an experimental 100 kW wind-energy generation system are described, and the results of current field tests are presented. The experimental wind turbine is a two-bladed down-wind horizontal axis propeller type with a 29.4 m diameter rotor and a tower 28 m in height. The plant was completed in March, 1983, and has been undergoing trouble-free tests since then. The present program calls for field tests during two years from fiscal 1983 to 1984. The development of technologies relating to the linkage and operation of wind-energy power generation system networks is planned along with the acquisition of basic data for the development of a large-scale wind energy power generation system.

Source record↗
NASA NTRS1984

Starbursts in Galaxies: Implications of Molecular and Far-infrared Observations

Starburst galaxies are defined in several ways (colors, optical spectroscopic signatures, and excess radio flux), and observational evidence indicating that episodes of rapid star formation occur in many galaxies with active nuclei is presented. There is a good correlation of 100 micron luminosity with CO emission, and of both quantities with excess nonthermal radio flux. This fact requires some linkage between central and global star formation rates. In addition, the presence of starbusts distorts the appearance of the molecular gas in which they occur. Using far infrared color temperatures and comparisons of CO isotopes, it is shown that the strong (12)CO emission in these galaxies does not accurately trace the H2 distribution, probably because the starburst raises the avearage temperature of the cloud ensemble.

Rickard, L. J.↗
NASA NTRS1985

Remote sensing of directional wave spectra using the surface contour radar

A unique radio-oceanographic remote sensing instrument was developed. The 36 GHz airborne Surface Contour Radar (SCR) remotely produces a real-time topographical map of the sea surface beneath the aircraft. It can routinely produce ocean directional wave spectra with off-line data processing. The transmitter is a coherent dual-frequency device that uses pulse compression to compensate for the limited available power at Ka band. The radar has selectable pulse widths of 1, 2, 4, and 10 nanoseconds. The transmitting antenna is a 58 lambda horn fed dielectric lens whose axis is parallel to the longitudinal axis of the aircraft. It illuminates an elliptical mirror which is oriented 45 deg to the lens' longitudinal axis to deflect the beam towards the region beneath the aircraft. The mirror is oscillated in a sinusoidal fashion through mechanical linkages driven to a variable speed motor to scan the transmitter beam (1.2 deg X 1.2 deg) with + or - 16 deg of the perpendicular to the aircraft wings in the plane perpendicular to the aircraft flight direction.

Walsh, E. J.↗