Ionization waves in the PK-4 direct current neon discharge
Explore the source record for details and available documents.
Peter Hartmann↗
SEARCH · Search NASA
Results for “Direct current”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Episode 8: Ho-Ho-How Holiday Lights Work (Direct Current – An Energy.gov Podcast)
Why do holiday lights burn out all the time? We find out the answer, and do it in rhyme.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Low-inductance direct current power bus
A DC power bus having reduced parasitic inductance and higher tolerable operating temperature is disclosed. In example embodiments, a bus structure overlies a printed circuit board, and an array of capacitors is arranged on a surface of the printed circuit board distal the bus structure. The bus structure comprises an upper metal plate, a lower metal plate, and a dielectric film interposed between the upper and lower metal plates. The capacitors are connected in parallel between conductive planes of the printed circuit board. The upper and lower metal plates of the bus structure are connected to respective conductive planes of the printed circuit board.
Neely, Jason C.↗
Medium Voltage Direct Current Power Electronics for Alaska Remote Community Interties.
Abstract not provided.
Atcitty, Stanley↗
High-frequency direct current bulk capacitors with interleaved busbar packages
Presented are electrical capacitors with interleaved busbar architectures, methods for making/operating such capacitors, and electric-drive vehicles equipped with such capacitors. A bulk capacitor includes multiple capacitor devices disposed within an outer housing and operable to modify electric current transmitted between a power source and an electrical load. An interleaved busbar package is interposed between the capacitor devices and outer housing. The interleaved busbar package includes a first busbar plate that electrically connects to first terminals of the capacitor devices and defines a busbar pocket. A second busbar plate is seated within the busbar pocket and electrically connects to second terminals of the capacitor devices. The second busbar plate includes a capacitor basin that seats therein the capacitor devices. An isolator sheet is interleaved between and electrically insulates the first and second busbar plates. The capacitor devices and interleaved busbar package may be partially submerged in an epoxy endfill composition.
42 ENGINEERING↗
Electronic assembly with a direct current bus connection
A folded outer tab comprises a first outer dielectric layer and a second outer dielectric layer that contact or overlie an outer terminal, where the outer terminal is associated with a first polarity of the DC bus. A bent inner tab comprises a first inner dielectric layer and a second inner dielectric layer that contact or overlie an inner terminal, where the inner terminal is associated with a second polarity of the DC bus that is opposite the first polarity. The folded outer tab and the bent inner tab comprise electrically conductive faces, of opposite polarities, formed of exposed portions of the outer terminal and the inner terminal.
Schmit, Christopher J.↗
Direct current momentary circuit interrupter
A momentary circuit interrupter in series connection with a mechanical switch to provide protection against short circuit faults in a DC power circuit. The momentary circuit interrupter injects a transient voltage pulse via a pulse transformer to reduce a DC fault current to near zero in a DC circuit branch, thus allowing the mechanical switch to disconnect the faulty branch under a near zero-current condition. The power electronic circuit on the primary side of the transformer controls the discharge of a plurality of pre-charged capacitors to generate the transient voltage pulse during the fault interruption process, but otherwise does not incur any power loss during normal operation. The secondary winding of the pulse transformer conducts the main DC current, and is highly conductive to minimize the conduction power loss. The invention provides ultrafast response to a short circuit fault (even faster than solid-state circuit breakers and much faster than hybrid circuit breakers), significantly reduced overcurrent stress in the power system, and/or ultralow conduction power losses.
Shen, Zheng John↗
Orientation-Dependent Distortion of Lamellae in a Block Copolymer Electrolyte under DC Polarization
Lithium-salt-doped block copolymers have the potential to serve as solid electrolytes in rechargeable batteries with lithium metal anodes. In this work, we use small-angle X-ray scattering (SAXS) to study the structure of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) doped with bis-(trifluoromethylsulfonyl)amine lithium salt (LiTFSI) during direct current (dc) polarization experiments in lithiu-lithium symmetric cells. The block copolymer studied is nearly symmetric in composition, has a total molecular weight of 39 kg mol -1 , and exhibits a lamellar morphology at all studied salt concentrations. When ionic current is passed through the electrolyte, a salt concentration gradient forms that induces a spatial gradient in the domain spacing, d. The dependence of d on distance from the positive electrode, x, was determined experimentally by scanning the incident X-ray beam from one lithium electrode to the other. By studying the two-dimensional (2D) SAXS patterns as a function of azimuthal scattering angle, we find that lamellae with PS/PEO interfaces oriented perpendicular to the flow of ionic current (LAM ⟂ ) swell and contract to a greater degree than those with interfaces oriented parallel to the current direction (LAM || ). While domains with the LAM ⟂ do not provide direct conducting pathways between the electrodes, our analysis suggests that they play an important role in establishing the salt concentration gradient necessary for sustaining a large ionic current through greater expansion and contraction.
25 ENERGY STORAGE↗
DPE Techno-Economic Analyses
This National Energy Technology Laboratory (NETL) report presents the results of an extensive set of techno-economic analyses for several open-cycle coal fuel oxy-fired direct power extraction (DPE) concepts. These power cycles make use of a conducting plasma accelerated through a magnetic field to generate direct current directly without the need for moving parts. Similar to gas turbines, the efficiency of the power cycle increases with increasing working fluid temperature and typically, plasma temperatures are much higher than the inlet temperature of even the most advanced gas turbine available today, affording the opportunity for very high cycle efficiencies. Most of the study uses high-fidelity models to assess a coal-fueled oxy-combustion DPE system with an AUSC steam bottoming cycle. Two baseline configurations were explored, one with relatively conservative operating point parameters and another with relatively aggressive operating point parameters. Additional analysis on the high-fidelity models as well as reduced order models were performed to analyze the cost and performance potential more thoroughly for the baseline systems and to compare their performance to two alternate open-cycle DPE systems.
30 DIRECT ENERGY CONVERSION↗
Load-Packaged AC/DC and DC/DC Power Electronics Converter Performance Data
This data set contains experimentally characterized performance data from load-packaged alternating current to direct current (AC/DC) and direct current to direct current (DC/DC) power electronics converters associated with lighting devices and miscellaneous electrical loads typically found in commercial buildings in the United States. The data set contains input power, output power, efficiency, and harmonic spectrum data for 58 AC/DC converters and 35 DC/DC converters.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Calibration Laboratory Capabilities Listing as of April 2009
This document reviews the Calibration Laboratory capabilities for various NASA centers (i.e., Glenn Research Center and Plum Brook Test Facility Kennedy Space Center Marshall Space Flight Center Stennis Space Center and White Sands Test Facility.) Some of the parameters reported are: Alternating current, direct current, dimensional, mass, force, torque, pressure and vacuum, safety, and thermodynamics parameters. Some centers reported other parameters.
Kennedy, Gary W.↗
Low-Power Magnetic Current Sensor
Direct current sensed via saturable-core reactor. Transducer senses direct current magnetically, providing isolation between input and output. Detecting-and-isolating element saturable reactor, where input current passes through one-turn control coil. Provides output of 0 to 3 Vdc for input current of 0 to 15 Adc and consumes power of 22 mW at 10 Adc input. Input sensed magnetically, output electrically isolated from input.
Mclyman, W. T.↗
DC current controller for continuously variable series reactor
A direct current controller includes a rectifier configured to convert alternating current input into a direct current output. A converter electrically coupled to the rectifier generates a converted direct current voltage that regulates a converted direct current from the direct current output of the rectifier and synthesizes an ac component of an alternating current grid to counteract an induced back-emf. A direct current controller central controller coupled to the converter regulates the converted direct current.
Wang, Fei (Fred)↗
Space Station Freedom secondary power wiring requirements
Secondary power is produced by DDCU's (direct current to direct current converter units) and routed to and through secondary power distribution assemblies (SPDA's) to loads or tertiary distribution assemblies. This presentation outlines requirements of Space Station Freedom (SSF) EEE (electrical, electronic, and electromechanical) parts wire and the approved electrical wire and cable. The SSF PDRD (Program Definition and Requirements Document) language problems and resolution are reviewed. The cable routing to and from the SPDA's is presented as diagrams and the wire recommendations and characteristics are given.
Sawyer, C. R.↗
Interleaved multi-channel, multi-level, multi-quadrant DC-DC converters
Direct-current-to-direct-current (DC-DC) power converters that include two or more multi-quadrant, multi-level, DC-DC, switching converter subcircuits, connected in parallel at respective input and output sides, so as to provide a multi-channel, multi-quadrant, multi-level configuration, are disclosed. The DC-DC power converters further include a control circuit configured to control the switching converter subcircuits so that corresponding switching semiconductors in each of the switching converter subcircuits are switched in an interleaved manner. In some embodiments, each of the switching converter subcircuits is a three-level, neutral-point-clamped, four-quadrant DC-DC converter circuit. In other embodiments, each of the switching converter subcircuits is a three-level, neutral-point-clamped, two-quadrant DC-DC converter circuit. In any of these embodiments, a filter capacitor may be connected between across a pair of output terminals at the output sides of the switching converter subcircuits.
Du, Yu↗
Research on the Corrosion Behavior of X70 Pipeline Steel Under Coupling Effect of AC + DC and Stress
The coupling effect of stray AC (alternating current) + DC (direct current) and tensile stress-induced X70 pipeline corrosion is complicated with its mechanism uncovered. In this work, the corrosion behavior of X70 pipeline steel under three different corrosion (including an individual AC corrosion, mixed AC + 150 MPa tensile stress corrosion, coupling effect of AC + a 30 A/m{sup 2} DC interference and 150 MPa tensile stress corrosion) conditions in Dagang soil simulated solution was investigated by COMSOL Multiphysics software simulation, electrochemical tests, scanning electron microscope and other techniques. The results indicated that with the increase in AC density, the open-circuit potential of the X70 steel samples was negatively shifted and corrosion rate increased in three different corrosion conditions. The corrosion rates of X70 steel samples under individual AC interference were almost unchanged when 150.9 MPa tensile stress was applied. When applying 30 A/m{sup 2} DC interference, the corrosion rate of X70 steel increases significantly. Therefore, the factors affecting corrosion performance of X70 pipeline steel were DC > AC > stress. Under individual AC interference, uniform corrosion occurred on the X70 steel at an AC current density of less than 30 A/m{sup 2}, while the pitting corrosion occurred at an AC current density of greater than 100 A/m{sup 2}. The application of tensile stress and DC had a certain inhibitory effect on pitting corrosion.
36 MATERIALS SCIENCE↗
Directional solidification of a planar interface in the presence of a time-dependent electric current
Directional solidification of pure materials and binary alloys with a planar crystal-metal interface in the presence of a time-dependent electric current is considered. For a variety of time-dependent currents, the temperature fields and the interface velocity as functions of time are presented for indium antimonide and bismuth and for the binary alloys germanium-gallium and tin-bismuth. For the alloys, the solid composition is calculated as a function of position. Quantitative predictions are made of the effect of an electrical pulse on the solute distribution in the solidified material.
Brush, L. N.↗