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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Apparatus for use in the production of ribbon-shaped crystals from a silicon melt

A susceptor for facilitating induction heating of silicon melt is described. The susceptor comprises a pair of susceptor halves of a thickness less than two skin depths, each being the mirror image of the other, disposed in mutually opposed, electrically insulated relation. The crucible comprises a quartz body supported by the graphite susceptor, whereby the R-F coil is electrically coupled with the melt.

Berkman, S.↗
NASA NTRS1983

Electrodynamics of the stratosphere using 5000 cu m superpressure balloons

The Electrodynamics of the Middle Atmosphere research project encompasses the design of a microprocessor-controlled payload and the launch of up to eight small superpressure balloons in the 1982-1984 period. The primary payload instrument will measure the vector electric field from dc to 10 kHz, and the payloads will include instruments measuring local ionization, electrical conductivity, magnetic field, and temperature and pressure fluctuations. In addition, optical lightning will be recorded. The simultaneous measurement of these stratospheric parameters by several balloons, for periods extending over several solar rotations, will allow the study of electrical coupling between atmosphere and magnetosphere, of global current systems, and of global response to solar flares and magnetospheric storms.

Holzworth, R. H.↗
NASA NTRS1984

Observation of interplanetary magnetic field and of ionospheric plasma convection in the vicinity of the dayside polar cleft

Dayside ionosphere convection at high latitudes has been examined during a series of experiments using the Sondrestrom radar together with ancillary observations of the interplanetary magnetic field (IMF) by the IMP-8 spacecraft. The radar experiments obtained a latitude coverage of 67.6 to 81.3 deg Lambda and a temporal resolution of between 14 to 25 minutes. A total of 17 rotations through the dayside cleft region during April, June and July, 1983 have been examined. The observations show two convection cells with sunward flow at lower latitudes and antisunward flow at higher latitudes. The flow commonly rotates through a 180 deg angle resulting in the predominant appearance of east-west flows. Rapid temporal variations in the convection velocities are frequently observed. Many of the high latitude variations in convection velocity appear to be directly related to variations in the IMF By component, with eastward (westward) velocity associated with negative (positive) By. This is strong evidence for a direct electrical coupling between the solar wind and dayside high latitude ionosphere.

Clauer, C. R.↗
NASA NTRS1987

Electrodynamic plasma motor/generator experiment

The Plasma Motor/Generator Proof of Function (PMG/POF) experiment, a low-cost payload for flight aboard the Shuttle Orbiter using the Hitchhiker G carrier, is discussed. The primary objective of this experiment is to verify that hollow cathode plasma sources can couple electric currents from either end of a long wire moving through the space plasma in LEO into and through that plasma to produce a PMG circuit. The support structure and the electrical components of the experiment are described. The experimental operation is discussed, including the calibration, experimental measurements, and follow-on missions.

Mccoy, James E.↗
NASA NTRS1988

Comparison of plasma sheet ion composition with the IMF and solar wind plasma

Plasma sheet energetic ion data (0.1- to 16 keV/e) obtained by the Plasma Composition Experiment on ISEE-1 between 10 and 23 earth radii are compared with concurrent IMF and solar wind plasma data. The densities of H(+) and He(++) ions in the plasma sheet are found to be the highest, and the most nearly proportional to the solar wind density, when the IMF B(z) is not northward. The density of terrestrial O(+) ions increases strongly with increasing magnitude of the IMF, in apparent agreement with the notion that the IMF plays a fundamental role in the electric coupling between the solar wind and the ionosphere.

Lennartsson, W.↗
NASA NTRS1992

Generation of dynamo magnetic fields in the primordial solar nebula

The present treatment of dynamo-generated magnetic fields in the primordial solar nebula proceeds in view of the ability of the combined action of Keplerian rotation and helical convention to generate, via alpha-omega dynamo, large-scale magnetic fields in those parts of the nebula with sufficiently high, gas-and magnetic field coupling electrical conductivity. Nebular gas electrical conductivity and the radial distribution of the local dynamo number are calculated for both a viscous-accretion disk model and the quiescent-minimum mass nebula. It is found that magnetic fields can be easily generated and maintained by alpha-omega dynamos occupying the inner and outer parts of the nebula.

Stepinski, Tomasz F.↗
NASA NTRS1994

Spline-Screw Payload-Fastening System

Payload handed off securely between robot and vehicle or structure. Spline-screw payload-fastening system includes mating female and male connector mechanisms. Clockwise (or counter-clockwise) rotation of splined male driver on robotic end effector causes connection between robot and payload to tighten (or loosen) and simultaneously causes connection between payload and structure to loosen (or tighten). Includes mechanisms like those described in "Tool-Changing Mechanism for Robot" (GSC-13435) and "Self-Aligning Mechanical and Electrical Coupling" (GSC-13430). Designed for use in outer space, also useful on Earth in applications needed for secure handling and secure mounting of equipment modules during storage, transport, and/or operation. Particularly useful in machine or robotic applications.

Vranish, John M.↗
NASA NTRS1996

Macroscopic Violation of Three Cauchy-Schwarz Inequalities Using Correlated Light Beams From an Infra-Red Emitting Semiconductor Diode Array

We briefly review quantum mechanical and semi-classical descriptions of experiments which demonstrate the macroscopic violation of the three Cauchy-Schwarz inequalities: g(sup 2)(sub 11)(0) greater than or equal to 1; g(sup 2)(sub 11)(0) greater than or equal to g(sup 2)(sub 11)(t), (t approaches infinity); (the absolute value of g(sup 2)(sub 11)(0))(exp 2) less than or equal to g(sup 2)(sub 11)(0) g(sup 2)(sub 11)(0). Our measurements demonstrate the violation, at macroscopic intensities, of each of these inequalities. We show that their violation, although weak, can be demonstrated through photodetector current covariance measurements on correlated sub-Poissonian Poissonian, and super Poissonian light beams. Such beams are readily generated by a tandem array of infrared-emitting semiconductor junction diodes. Our measurements utilize an electrically coupled array of one or more infrared-emitting diodes, optically coupled to a detector array. The emitting array is operated in such a way as to generate highly correlated beams of variable photon Fano Factor. Because the measurements are made on time scales long compared with the first order coherence time and with detector areas large compared with the corresponding coherence areas, first order interference effects are negligible. The first and second inequalities are violated, as expected, when a sub-Poissonian light beam is split and the intensity fluctuations of the two split beams are measured by two photodetectors and subsequently cross-correlated. The third inequality is violated by bunched (as well as anti-bunched) beams of equal intensity provided the measured cross correlation coefficient exceeds (F - 1)/F, where F is the measured Fano Factor of each beam. We also investigate the violation for the case of unequal beams.

Edwards, P. J.↗
NASA NTRS1999

Acceleration Processes in the Cusp -- Observations by the FAST Satellite

The FAST spacecraft has encountered the Earth's cusp regions near its apogee of 4175 km on numerous occasions during its first two and half years of operations. The cusp encounters are identified by their signatures of keV dispersed ion injections of solar wind origin. The FAST instruments reveal a complex microphysics inherent to many, but not all, of the cusp regions encountered by the spacecraft, that often include upgoing ion beams within regions of downgoing electrons that may appear as series of inverted-V features with energies near a few hundred eV. In many instances, upgoing electron beams have also been observed. Intense (> 100 mV/m) spikey DC-coupled electric fields and plasma waves are common features of the cusp encounters which also provide evidence for the presence of such local acceleration processes. In some cases, the FAST data show clear modulation of the precipitating magnetosheath ions indicative that they are affected by local electric potentials, as evidenced by simultaneous electron acceleration within such intervals. Furthermore, the acceleration events are sometimes organized with an apparent cellular structure that suggest Alfven waves or other large scale phenomena are controlling the localized potentials. We examine several cusp encounters in detail in order to study the complex relation of the cusp energetic particle populations with the plasma waves and DC electric fields.

Pfaff, R. F.↗
NASA NTRS1999

Acceleration Processes in the Cusp: Observations by the FAST Satellite

The Fast Auroral Snapshot (FAST) spacecraft has encountered the Earth's cusp regions near its apogee of 4175 km on numerous occasions during its first two and half years of operations. The cusp encounters are identified by their signatures of keV dispersed ion injections of solar wind origin. The FAST instruments reveal a complex microphysics inherent to many, but not all, of the cusp regions encountered by the spacecraft, that often include upgoing ion beams within regions of downgoing electrons that may appear as series of inverted-V features with energies near a few hundred eV. In many instances, upgoing electron beams have also been observed. Intense (> 100 mV/m) spikey DC-coupled electric fields and plasma waves are common features of the cusp encounters which also provide evidence for the presence of such local acceleration processes. In some cases, the FAST data show clear modulation of the precipitating magnetosheath ions indicative that they are affected by local electric potentials, as evidenced by simultaneous electron acceleration within such intervals. Furthermore, the acceleration events are sometimes organized with an apparent cellular structure that suggest Alfv6n waves or other large scale phenomena are controlling the localized potentials. We examine several cusp encounters in detail in order to study the complex relation of the cusp energetic particle populations with the plasma waves and DC electric fields.

Pfaff, R. F.↗
NASA NTRS1998

Polar Cap Plasma and Convection

This presentation will describe the character of the polar cap plasma in 10% AGU Spring 1998 particular the convection velocities at the perigee (about 1.8 Re) and apogee( about 8.9 Re) of Polar in relationship to Interplanetary Magnetic Field (IMF) and solar wind parameters. This plasma is thought to be due to several sources; the polar wind, cleft ion fountain, and auroral outflow. The plasma in the polar cap tends to be mostly field-aligned. At any given point in the polar cap, this plasma could be from a different regions since convection of magnetic field lines can transport this material. it is quite difficult to study such a phenomena with single point measurements. Current knowledge of the polar cap plasma obtained by in situ measurements will be presented along with recent results from the Polar mission. This study also examines the direct electrical coupling between the magnetosphere and ionosphere by comparing convection velocities measured by the Thermal Ion Dynamics Experiment (TIDE) and Magnetic Field Experiment (MFE) instruments in magnetosphere and measurements of the ionosphere by ground-based radars. At times such a comparison is difficult because the Polar satellite at apogee spends a large amount of time in the polar cap which is a region that is not coverage well by the current SuperDam coherent radars. This is impart due to the lack of irregularities that returns the radar signal.

Elliott, Heather A.↗
NASA NTRS2001

Physical and Electronic Isolation of Carbon Nanotube Conductors

Multi-walled nanotubes are proposed as a method to electrically and physically isolate nanoscale conductors from their surroundings. We use tight binding (TB) and density functional theory (DFT) to simulate the effects of an external electric field on multi-wall nanotubes. Two categories of multi-wall nanotube are investigated, those with metallic and semiconducting outer shells. In the metallic case, simulations show that the outer wall effectively screens the inner core from an applied electric field. This offers the ability to reduce crosstalk between nanotube conductors. A semiconducting outer shell is found not to perturb an electric field incident on the inner core, thereby providing physical isolation while allowing the tube to remain electrically coupled to its surroundings.

OKeeffe, James↗
NASA NTRS2007

System and Method for Monitoring Piezoelectric Material Performance

A system and method are provided for monitoring performance capacity of a piezoelectric material that may form part of an actuator or sensor device. A switch is used to selectively electrically couple an inductor to the piezoelectric material to form an inductor-capacitor circuit. Resonance is induced in the inductor-capacitor circuit when the switch is operated to create the circuit. The resonance of the inductor-capacitor circuit is monitored with the frequency of the resonance being indicative of performance capacity of the device's piezoelectric material.

Moses, Robert W.↗
NASA NTRS2007

Thermal modulation for gas chromatography

A thermal modulator device for gas chromatography and associated methods. The thermal modulator device includes a recirculating fluid cooling member, an electrically conductive capillary in direct thermal contact with the cooling member, and a power supply electrically coupled to the capillary and operable for controlled resistive heating of the capillary. The capillary can include more than one separate thermally modulated sections.

Hasselbrink, Ernest F.↗
NASA NTRS2007

Thermal modulation for gas chromatography

A thermal modulator device for gas chromatography and associated methods. The thermal modulator device includes a cooling member, an electrically conductive capillary in direct thermal contact with the cooling member, and a power supply electrically coupled to the capillary and operable for controlled resistive heating of the capillary.

Hasselbrink, Ernest F.↗
NASA NTRS2007

Using G4FETs as a Data Router for In-Plane Crossing of Signal Paths

Theoretical analysis and some experiments have demonstrated that siliconon- insulator (SOI) 4-gate transistors the type known as G(exp 4)FETs could be efficiently used for in-plane crossing of signal paths. Much of the effort of designing very-large-scale integrated (VLSI) circuits is focused on area-efficient routing of signals. The main source of difficulty in VLSI signal routing is the requirement to prevent crossing, in the same plane, of wires that are meant to be kept electrically insulated from each other. Consequently, it often becomes necessary to design and build VLSI circuits in multiple layers with vias (connections between conductors in different layers at selected locations). Suitable devices that would prevent, or at least sufficiently suppress, undesired electrical coupling (cross-talk) between wires crossing in the same plane would enable compact, simpler implementation complex interconnection networks with in-plane crossings that, heretofore, have not been possible in VLSI circuitry. The use of G4FETs as in-plane signal-crossing devices or routers, in combination with the use of G(exp 4)FETs as universal programmable logic gates, would create opportunities for reducing complexity in VLSI design.

Fijany, Amir↗
NASA NTRS2010

NASA Tech Briefs, May 2010

Topics covered include: Instrument for Analysis of Greenland's Glacier Mills Cryogenic Moisture Apparatus; A Transportable Gravity Gradiometer Based on Atom Interferometry; Three Methods of Detection of Hydrazines; Crossed, Small-Deflection Energy Analyzer for Wind/Temperature Spectrometer; Wavefront Correction for Large, Flexible Antenna Reflector; Novel Micro Strip-to-Waveguide Feed Employing a Double-Y Junction; Thin-Film Ferro Electric-Coupled Microstripline Phase Shifters With Reduced Device Hysteresis; Two-Stage, 90-GHz, Low-Noise Amplifier; A 311-GHz Fundamental Oscillator Using InP HBT Technology; FPGA Coprocessor Design for an Onboard Multi-Angle Spectro-Polarimetric Imager; Serrating Nozzle Surfaces for Complete Transfer of Droplets; Turbomolecular Pumps for Holding Gases in Open Containers; Triaxial Swirl Injector Element for Liquid-Fueled Engines; Integrated Budget Office Toolbox; PLOT3D Export Tool for Tecplot; Math Description Engine Software Development Kit; Astronaut Office Scheduling System Software; ISS Solar Array Management; Probabilistic Structural Analysis Program; SPOT Program; Integrated Hybrid System Architecture for Risk Analysis; System for Packaging Planetary Samples for Return to Earth; Offset Compound Gear Drive; Low-Dead-Volume Inlet for Vacuum Chamber; Simple Check Valves for Microfluidic Devices; A Capillary-Based Static Phase Separator for Highly Variable Wetting Conditions; Gimballing Spacecraft Thruster; Finned Carbon-Carbon Heat Pipe with Potassium Working Fluid; Lightweight Heat Pipes Made from Magnesium; Ceramic Rail-Race Ball Bearings; Improved OTEC System for a Submarine Robot; Reflector Surface Error Compensation in Dual-Reflector Antennas; Enriched Storable Oxidizers for Rocket Engines; Planar Submillimeter-Wave Mixer Technology with Integrated Antenna; Widely Tunable Mode-Hop-Free External-Cavity Quantum Cascade Laser; Non-Geiger-Mode Single-Photon Avalanche Detector with Low Excess Noise; Using Whispering-Gallery-Mode Resonators for Refractometry; RF Device for Acquiring Images of the Human Body; Reactive Collision Avoidance Algorithm; Fast Solution in Sparse LDA for Binary Classification; Modeling Common-Sense Decisions in Artificial Intelligence; Graph-Based Path-Planning for Titan Balloons; Nanolaminate Membranes as Cylindrical Telescope Reflectors; Air-Sea Spray Airborne Radar Profiler Characterizes Energy Fluxes in Hurricanes; Large Telescope Segmented Primary Mirror Alignment; and Simplified Night Sky Display System.

Source record↗
NASA NTRS2011

Fast-responding short circuit protection system with self-reset for use in circuit supplied by DC power

A short circuit protection system includes an inductor, a switch, a voltage sensing circuit, and a controller. The switch and inductor are electrically coupled to be in series with one another. A voltage sensing circuit is coupled across the switch and the inductor. A controller, coupled to the voltage sensing circuit and the switch, opens the switch when a voltage at the output terminal of the inductor transitions from above a threshold voltage to below the threshold voltage. The controller closes the switch when the voltage at the output terminal of the inductor transitions from below the threshold voltage to above the threshold voltage.

Burns, Bradley M.↗