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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 901 records · Page 50

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NASA NTRS1982

Progress in 800 x 800 charge-coupled device /CCD/ imager development and applications

Performance parameters of the 800 x 800 three phase and virtual phase CCD imaging sensors for the planned Project Galileo and Space Telescope Wide Field/Planetary Camera are compared, and the significance of some of the parameters for device radiation performance is discussed. The problems encountered by the three phase device that resulted in its being considered not suitable for the Galileo mission are described, and the radiation hardening performed on the virtual phase device to permit it to cope with Jupiter's radiation belts is addressed. Major research tasks in the effort to advance the technology of large area virtual phase imagers are stated.

Norris, D. D.↗

NASA NTRS1983

Prosthetic occlusive device for an internal passageway

An occlusive device is disclosed for surgical implant to occlude the lumen of an internal organ. The device includes a cuff having a backing collar and two isolated cuff chambers. The fluid pressure of one chamber is regulated by a pump/valve reservoir unit. The other chamber is unregulated in pressure but its fluid volume is adjusted by removing or adding fluid to a septum/reservoir by means of a hypodermic needle. Pressure changes are transmitted between the two cuff chambers via faying surfaces which are sufficiently large in contact area and thin as to transmit pressure generally without attenuation. By adjusting the fluid volume of the septum, the operating pressure of the device may be adjusted to accommodate tubular organs of different diameter sizes as well as to compensate for changes in the organ following implant without reoperation.

Tenney, J. B., Jr.↗

NASA NTRS1983

Inflatable device for installing strain gage bridges

Methods and devices for installing in a tubular shaft multiple strain gages are disclosed with focus on a method and a device for pneumatically forcing strain gages into seated engagement with the internal surfaces of a tubular shaft in an installation of multiple strain gages in a tubular shaft. The strain gages or other electron devices are seated in a template-like component which is wrapped about a pneumatically expansible body. The component is inserted into a shaft and the body is pneumatically expanded after a suitable adhesive was applied to the surfaces.

Cook, C. E.↗

NASA NTRS1983

Initial experimental results from a laboratory size beam plasma discharge device

A laboratory beam plasma discharge (BPD) device produced BPD in N2, A, and He. All features of the BPD observed in the device agree with those observed in a large vacuum chamber. The empirical ignition criteria determined in the large chamber apply in the small device but do not fit when used for extrapolation between the large and the small geometry. At some energies and magnetic fields beam currents exist for which the total light output in the BPD state varies by a factor of 2 with a factor of 6 pressure variation. Above 0.0001 torr the BPD width is pressure independent but for lower pressures it expands by as much as a factor of 4 at 0.00002 torr.

Konradi, A.↗

NASA NTRS1983

Pressure letdown method and device for coal conversion systems

In combination with a reactor for a coal utilization system, a pressure letdown device accepts from a reactor, a polyphase fluid at an entrance pressure and an entrance velocity, and discharges the fluid from the device at a discharge pressure substantially lower than the entrance pressure and at a discharge temperature and a discharge velocity substantially equal to the entrance temperature and entrance velocity. The device is characterized by a series of pressure letdown stages including several symmetrical baffles, disposed in coaxially nested alignment. In each baffle several ports or apertures of uniform dimensions are defined. The number of ports or apertures for each baffle plate is unique with respect to the number of ports or apertures defined in each of the other baffles. The mass rate of flow for each port is a function of the area of the port, the pressure of the fluid as applied to the port, and a common pressure ratio established across the ports.

Kendal, J. M.↗

NASA NTRS1984

Millimeter wave transmission systems and related devices

A survey was made of the state-of-the-art in millimeter (20 GHz to 300 GHz) wave transmission systems and related devices. The survey includes summaries of analytical studies and theoretical results that were obtained for various transmission line structures. This material was supplemented by further analysis where appropriate. The transmission line structures are evaluated in terms of electrical performance, ease of manufacture, usefulness for building other devices and compatibility with solid state devices. Descriptions of waveguide transmission lines which have commonly been used in the microwave frequency range are provided along with special attention given to the problems that these guides face when their use is extended into the millimeter wave range. Also, guides which have been introduced specifically to satisfy the requirements of millimeter wave transmission are discussed in detail.

Hebert, L. M.↗

NASA NTRS1984

A survey of gas-side fouling measuring devices

A survey of measuring devices or probes, which were used to investigate gas side fouling, was carried out. Five different types of measuring devices are identified and discussed including: heat flux meters, mass accumulation probes, optical devices, deposition probes, and acid condensation probes. A total of 32 different probes are described in detail and summarized in matrix or tabular form. The important considerations of combustion gas characterization and deposit analysis are also given a significant amount of attention. The results show that considerable work was done in the development of gas side fouling probes. However, it is clear that the design, construction, and testing of a durable, versatile probe - capable of monitoring on-line fouling resistances - remains a formidable task.

Marner, W. J.↗

NASA NTRS1983

Latchup in CMOS devices from heavy ions

It is noted that complementary metal oxide semiconductor (CMOS) microcircuits are inherently latchup prone. The four-layer n-p-n-p structures formed from the parasitic pnp and npn transistors make up a silicon controlled rectifier. If properly biased, this rectifier may be triggered 'ON' by electrical transients, ionizing radiation, or a single heavy ion. This latchup phenomenon might lead to a loss of functionality or device burnout. Results are presented from tests on 19 different device types from six manufacturers which investigate their latchup sensitivity with argon and krypton beams. The parasitic npnp paths are identified in general, and a qualitative rationale is given for latchup susceptibility, along with a latchup cross section for each type of device. Also presented is the correlation between bit-flip sensitivity and latchup susceptibility.

Soliman, K.↗

NASA NTRS1985

Variable-Temperature-Gradient Device for Solidification Research

Device for research in solidification and crystal growth allows crystallization of melt observed as occurs. Temperature gradient across melt specimen increased or decreased rapidly while solidification front proceeds at constant speed across sample. Device moves sample at same speed, thereby holding position of liquid/solid interface stationary within field of optical microscope. Device, variabletemperature-gradient microscope stage, used to study crystal growth at constant rate while thermal driving force is varied.

Kaukler, W. F.↗

NASA NTRS1985

Spill-Detector-and-Shutoff Device

Overflow in liquid chromatography systems rapidly detected and stopped. Spill-detector-and-shutoff device incorporated into liquid-chromatography system. When liquid from output nozzle spills on liquid sensor, device automatically shuts off pump and releases solenoid to pinch off flow in tube. Device uses common type of alarm circuit reset manually before normal operation resumes.

Jarvis, M. R.↗

NASA NTRS1984

Overview of magnetic bearing control and linearization approaches for annular magnetically suspended devices

An overview of magnetic bearing control and linearization approaches which have been considered for annular magnetically suspended devices is presented. These devices include the Annular Momentum Control Device and the Annular Suspension and Pointing System. Two approaches were investigated for controlling the magnetic actuator. One approach involves controlling the upper and lower electromagnets differentially about a bias flux. The bias flux can either be supplied by permanent magnets in the magnetic circuit or by bias currents. In the other approach, either the upper electromagnet or the lower electromagnet is controlled depending on the direction of force required. One advantage of the bias flux is that for small gap perturbations about a fixed operating point, the force-current characteristic is linear. Linearization approaches investigated for individual element control include an analog solution of the nonlinear electromagnet force equation and a microprocessor-based table lookup method.

Groom, N. J.↗

NASA NTRS1984

Determining Training Device Requirements in Army Aviation Systems

A decision making methodology which applies the systems approach to the training problem is discussed. Training is viewed as a total system instead of a collection of individual devices and unrelated techniques. The core of the methodology is the use of optimization techniques such as the transportation algorithm and multiobjective goal programming with training task and training device specific data. The role of computers, especially automated data bases and computer simulation models, in the development of training programs is also discussed. The approach can provide significant training enhancement and cost savings over the more traditional, intuitive form of training development and device requirements process. While given from an aviation perspective, the methodology is equally applicable to other training development efforts.

Poumade, M. L.↗

NASA NTRS1984

Some thoughts on the implementation of pilot night vision devices for helicopters

Night vision enhancement devices greatly expand the range and quality of services by extending night operational capabilities. Evolving military tactical concepts for helicopters survivability and battlefield effectiveness necessitate nap-of-the-earth (NOE) flying under both day and night conditions. From a pilot workload standpoint, flying a helicopter NOE in day VFR conditions with minimum clearance between rotors and obstacles is quite demanding. Doing the same job at night is several times more difficult. There are two general categories of night vision devices in operation in helicopter aviation: the Night Vision Goggles (NVG) and forward looking infrared (FLIR) system. The capabilities and limitations of those two devices are discussed.

Tucker, G. E.↗

NASA NTRS1985

Feasibility of self-structured current accessed bubble devices in spacecraft recording systems

The self-structured, current aperture approach to magnetic bubble memory is described. Key results include: (1) demonstration that self-structured bubbles (a lattice of strongly interacting bubbles) will slip by one another in a storage loop at spacings of 2.5 bubble diameters, (2) the ability of self-structured bubbles to move past international fabrication defects (missing apertures) in the propagation conductors (defeat tolerance), and (3) moving bubbles at mobility limited speeds. Milled barriers in the epitaxial garnet are discussed for containment of the bubble lattice. Experimental work on input/output tracks, storage loops, gates, generators, and magneto-resistive detectors for a prototype device are discussed. Potential final device architectures are described with modeling of power consumption, data rates, and access times. Appendices compare the self-structured bubble memory from the device and system perspectives with other non-volatile memory technologies.

Nelson, G. L.↗

NASA NTRS1984

Si MOS devices at low temperatures

Low temperature operation of micron and submicron size Si MOSFETs (metal-oxide-semiconductor field-effect-transistors) results in their improved device characteristics. Various low temperature device properties such as increase in mobility, shift in the theshold voltage, increased reliability, etc., were considered. Other device characteristics such as the subthreshold behavior, delay times and miniaturization at low temperatures are discussed. Discussion includes presenting experimental results along with physical models explaining the observed effects.

Kamgar, A.↗

NASA NTRS1985

A life-saving device for ships

A life-saving device is described which can be used on either ships or airplanes. The device consists of an airtight container for passengers equipped with elements needed for survival (oxygen, food, medicines, etc.), an energy source, and a parachute. This device can be ejected from the plane or ship when an emergency arises.

Converti, P.↗

NASA NTRS1986

Combined Devices for Turbulent-Drag Reduction

Aircraft skin-friction drag reduced as much as 15 percent. One effective drag-reduction technique involves use of riblets. Riblets are longitudinal striations or grooves machined on originally smooth surface. Grooves alined with flow. Grooves have depths and spacings on order of turbulent wallstreak and burst dimensions and designed to change near-wall structure of turbulent boundary layer. Another approach, using large-eddy-breakup (LEBU) devices, or turbulence manipulators or ribbons also demonstrated reductions in local skin friction and net drag in air. LEBU device consists of thin, ribbonlike strips or airfoils suspended parallel to test surface and positioned within turbulent boundary layer. Technique potentially reduce net skin-friction drag by at least 15 percent on turbulent boundary layer of aircraft, representing possible annual savings in fuel costs of $300 to $400 million for U.S. commercial fleet. Also applicable to frictionloss reduction inside pipes and ducts, contributing to increased efficiency of pumps, heat exchangers, air conditioners, and other devices involving fluid flow.

Walsh, M. J.↗

NASA NTRS1985

Crystal Growth of Device Quality Gaas in Space

The GaAs research evolves about these key thrust areas. The overall program combines: (1) studies of crystal growth on novel approaches to engineering of semiconductor material (i.e., GaAs and related compounds); (2) investigation and correlation of materials properties and electronic characteristics on a macro- and microscale; and (3) investigation of electronic properties and phenomena controlling device applications and device performance. This effort is aimed at the essential ground-based program which would insure successful experimentation with and eventually processing of GaAs in near zero gravity environment. It is believed that this program addresses in a unique way materials engineering aspects which bear directly on the future exploitation of the potential of GaAs and related materials in device and systems applications.

Gatos, H. C.↗