Science.gov

Sample records for dc wiring system

  1. DC wiring system grounding and ground fault protection issues for central station photovoltaic power plants

    NASA Technical Reports Server (NTRS)

    Simburger, E. J.

    1983-01-01

    The DC wiring system for a photovoltaic power plant presents a number of unique challenges to be overcome by the plant designers. There are a number of different configurations that the grounding of the DC wiring system can take, and the choice will affect the number and type of protective devices required to ensure safety of personnel and protection of equipment. The major grounding and fault protection considerations that must be taken into account when selecting the basic overall circuit configuration are summarized. The inherent advantages and disadvantages of each type of circuit grounding (resistance or solid) along with the personnel safety and equipment protection issues for each of these grounding methods are presented.

  2. EXPERIMENTS WITH A DC WIRE IN RHIC

    SciTech Connect

    FISCHER,W.; CALAGA, R.; DORDA, U.; KOUTCHOUK, J.-P.; ZIMMERMANN, F.; SEN, T.

    2007-06-25

    A DC wire has been installed in RHIC to explore the long-range beam-beam effect, and test its compensation. We report on experiments that measure the effect of the wire's electro-magnetic field on the beam's lifetime and tune distribution, and accompanying simulations.

  3. LANSCE-R WIRE-SCANNER SYSTEM

    SciTech Connect

    Gruchalla, Michael E.

    2011-01-01

    The National Instruments cRIO platform is used for the new LANSCE-R wire-scanner systems. All wire-scanner electronics are integrated into a single BiRa BiRIO 4U cRIO chassis specifically designed for the cRIO crate and all interface electronics. The BiRIO chassis, actuator and LabVIEW VIs provide a complete wire-scanner system integrated with EPICS. The new wire-scanner chassis includes an 8-slot cRIO crate with Virtex-5 LX 110 FPGA and Power-PC real-time controller, the LANL-developed cRIO 2-axis wire-sensor analog interface module (AFE), NI9222 cRIO 4-channel 16-bit digitizer, cRIO resolver demodulator, cRIO event receiver, front-panel touch panel display, motor driver, and all necessary software, interface wiring, connectors and ancillary components. This wirescanner system provides a complete, turn-key, 2-axis wire-scanner system including 2-channel low-noise sensewire interface with variable DC wire bias and wireintegrity monitor, 16-bit signal digitizers, actuator motor drive and control, actuator position sensing, limit-switch interfaces, event receiver, LabVIEW and EPICS interface, and both remote operation and full stand-alone operation using the touch panel.

  4. A Prototype Wire Position Monitoring System

    SciTech Connect

    Wang, Wei

    2010-12-07

    The Wire Position Monitoring System (WPM) will track changes in the transverse position of LCLS Beam Position Monitors (BPMs) to 1{micro}m over several weeks. This position information will be used between applications of beam based alignment to correct for changes in component alignment. The WPM system has several requirements. The sensor range must be large enough so that precision sensor positioning is not required. The resolution needs to be small enough so that the signal can be used to monitor motion to 1{micro}m. The system must be stable enough so that system drift does not mimic motion of the component being monitored. The WPM sensor assembly consists of two parts, the magnetic sensor and an integrated lock-in amplifier. The magnetic sensor picks up a signal from the alternating current in a stretched wire. The voltage v induced in the sensor is proportional to the wire displacement from the center of the sensor. The integrated lock-in amplifier provides a DC output whose magnitude is proportional to the AC signal from the magnetic sensor. The DC output is either read on a digital voltmeter or digitized locally and communicated over a computer interface.

  5. DC systems with transformerless converters

    SciTech Connect

    Vithayathil, J.J.; Mittlestadt, W.; Bjoerklund, P.E.

    1995-07-01

    A technical and economic feasibility study of HVDC systems without converter transformers is presented. The presentation includes proposed solutions to the drawback related to the absence of galvanic separation between the ac and dc systems, if the converter transformers are eliminated. The results show that HVDC systems without converter transformers are both technically and economically feasible. The cost savings can be substantial.

  6. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Wiring systems. 393.28 Section 393.28 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.28 Wiring...

  7. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Wiring systems. 393.28 Section 393.28 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.28 Wiring...

  8. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Wiring systems. 393.28 Section 393.28 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.28 Wiring...

  9. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Wiring systems. 393.28 Section 393.28 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.28 Wiring...

  10. SpaceWire Data Handling Demonstration System

    NASA Astrophysics Data System (ADS)

    Mills, S.; Parkes, S. M.; O'Gribin, N.

    2007-08-01

    The SpaceWire standard was published in 2003 with the aim of providing a standard for onboard communications, defining the physical and data link layers of an interconnection, in order to improve reusability, reliability and to reduce the cost of mission development. The many benefits which it provides mean that it has already been used in a number of missions, both in Europe and throughout the world. Recent work by the SpaceWire community has included the development of higher level protocols for SpaceWire, such as the Remote Memory Access Protocol (RMAP) which can be used for many purposes, including the configuration of SpaceWire devices. Although SpaceWire has become very popular, the various ways in which it can be used are still being discovered, as are the most efficient ways to use it. At the same time, some in the space industry are not even aware of SpaceWire's existence. This paper describes the SpaceWire Data Handling Demonstration System that has been developed by the University of Dundee. This system simulates an onboard data handling network based on SpaceWire. It uses RMAP for all communication, and so demonstrates how SpaceWire and standardised higher level protocols can be used onboard a spacecraft. The system is not only a good advert for those who are unfamiliar with the benefits of SpaceWire, it is also a useful tool for those using SpaceWire to test ideas.

  11. A Vibrating Wire System For Quadrupole Fiducialization

    SciTech Connect

    Wolf, Zachary

    2010-12-13

    A vibrating wire system is being developed to fiducialize the quadrupoles between undulator segments in the LCLS. This note provides a detailed analysis of the system. The LCLS will have quadrupoles between the undulator segments to keep the electron beam focused. If the quadrupoles are not centered on the beam axis, the beam will receive transverse kicks, causing it to deviate from the undulator axis. Beam based alignment will be used to move the quadrupoles onto a straight line, but an initial, conventional alignment must place the quadrupole centers on a straight line to 100 {micro}m. In the fiducialization step of the initial alignment, the position of the center of the quadrupole is measured relative to tooling balls on the outside of the quadrupole. The alignment crews then use the tooling balls to place the magnet in the tunnel. The required error on the location of the quadrupole center relative to the tooling balls must be less than 25 {micro}m. In this note, we analyze a system under construction for the quadrupole fiducialization. The system uses the vibrating wire technique to position a wire onto the quadrupole magnetic axis. The wire position is then related to tooling balls using wire position detectors. The tooling balls on the wire position detectors are finally related to tooling balls on the quadrupole to perform the fiducialization. The total 25 {micro}m fiducialization error must be divided between these three steps. The wire must be positioned onto the quadrupole magnetic axis to within 10 {micro}m, the wire position must be measured relative to tooling balls on the wire position detectors to within 15 {micro}m, and tooling balls on the wire position detectors must be related to tooling balls on the quadrupole to within 10 {micro}m. The techniques used in these three steps will be discussed. The note begins by discussing various quadrupole fiducialization techniques used in the past and discusses why the vibrating wire technique is our method of choice. We then give an overview of the measurement system showing how the vibrating wire is positioned onto the quadrupole axis, how the wire position detectors locate the wire relative to tooling balls without touching the wire, and how the tooling ball positions are all measured. The novel feature of this system is the vibrating wire which we discuss in depth. We analyze the wire dynamics and calculate the expected sensitivity of the system. The note should be an aid in debugging the system by providing calculations to compare measurements to.

  12. DC Magnetics Measurement System Design

    NASA Technical Reports Server (NTRS)

    Mastny, Timothy

    2012-01-01

    This report will detail the updates to the magnetics measurement system design and testing procedures that are required for performing static (DC) magnetics testing of future flight hardware. An older magnetics testing system had to be integrated with new procedures and hardware to meet the demands of future testing programs and accommodate an upcoming magnetics tests. The next test will be for the Geostationary Operational Environmental Satellite R-Series (GOES-R), which will verify that the SAFT Battery component meets its specifications for magnetic cleanliness. The satellite is scheduled to launch in 2015 with magnetics testing to be completed on the battery in November 2012.

  13. In-Situ Wire Damage Detection System

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Roberson, Luke; Tate, Lanetra; Smith, Trent; Gibson, Tracy; Medelius, Pedro; Jolley, Scott

    2012-01-01

    An In-Situ Wire Damage Detection System (ISWDDS) has been developed that is capable of detecting damage to a wire insulation, or a wire conductor, or to both. The system will allow for realtime, continuous monitoring of wiring health/integrity and reduce the number of false negatives and false positives while being smaller, lighter in weight, and more robust than current systems. The technology allows for improved safety and significant reduction in maintenance hours for aircraft, space vehicles, satellites, and other critical high-performance wiring systems for industries such as energy production and mining. The integrated ISWDDS is comprised of two main components: (1) a wire with an innermost core conductor, an inner insulation film, a conductive layer or inherently conductive polymer (ICP) covering the inner insulation film, an outermost insulation jacket; and (2) smart connectors and electronics capable of producing and detecting electronic signals, and a central processing unit (CPU) for data collection and analysis. The wire is constructed by applying the inner insulation films to the conductor, followed by the outer insulation jacket. The conductive layer or ICP is on the outer surface of the inner insulation film. One or more wires are connected to the CPU using the smart connectors, and up to 64 wires can be monitored in real-time. The ISWDDS uses time domain reflectometry for damage detection. A fast-risetime pulse is injected into either the core conductor or conductive layer and referenced against the other conductor, producing transmission line behavior. If either conductor is damaged, then the signal is reflected. By knowing the speed of propagation of the pulse, and the time it takes to reflect, one can calculate the distance to and location of the damage.

  14. Telephone wire is backbone of security system

    SciTech Connect

    Brede, K.; Rackson, L.T.

    1995-09-01

    Video provides a variety of low-cost, high-quality solutions in today`s security environment. Cost-conscious managers of power generation stations, casinos, prison facilities, military bases and office buildings are considering using regular telephone wire (unshielded twisted pair-UTP) within their existing systems as the backbone of a video to the PC, personal and video-conferencing and training are other areas where phone wire in a building can save money and provide an alternative to coax or fiber for video. More and more, businesses and government agencies are meeting their needs efficiently by using telephone wires for more than just telephones.

  15. Inspection of anode and field wires for the COMPASS drift chamber, DC5, with Environmental Scanning Electron Microscope

    NASA Astrophysics Data System (ADS)

    Cyuzuzo, Sonia

    2014-09-01

    The COMPASS experiment at CERN uses a secondary pion beam from the Super Proton Synchrotron (SPS) at CERN to explore the spin structure of nucleons. A new drift chamber, DC5, will be integrated into the COMPASS spectrometer to replace an aging straw tube detector. DC5 will detect muon pairs from Drell-Yan scattering of a pion-beam off a transversely polarized proton target. This data will be used to determine the correlation between transverse proton spin and the intrinsic transverse momentum of up-quarks inside the proton, the Sivers effect. DC5 is a large area planar drift chamber with 8 layers of anode-frames made of G10 fiberglass-epoxy. The G10 frames support printed circuit boards for soldering 20 μm diameter anode and 100 μm diameter field wires. The anode planes are sandwiched by 13 graphite coated Mylar cathode planes. To ensure a well-functioning of DC5, the wires were carefully tested. An optical inspection and a spectral analysis was performed with an Environmental Scanning Electron Microscope (ESEM) to verify the composition and dimensions and the integrity of the gold plating on the surface of these wires. The spectra of the wires were studied at 10 and 30 keV. The COMPASS experiment at CERN uses a secondary pion beam from the Super Proton Synchrotron (SPS) at CERN to explore the spin structure of nucleons. A new drift chamber, DC5, will be integrated into the COMPASS spectrometer to replace an aging straw tube detector. DC5 will detect muon pairs from Drell-Yan scattering of a pion-beam off a transversely polarized proton target. This data will be used to determine the correlation between transverse proton spin and the intrinsic transverse momentum of up-quarks inside the proton, the Sivers effect. DC5 is a large area planar drift chamber with 8 layers of anode-frames made of G10 fiberglass-epoxy. The G10 frames support printed circuit boards for soldering 20 μm diameter anode and 100 μm diameter field wires. The anode planes are sandwiched by 13 graphite coated Mylar cathode planes. To ensure a well-functioning of DC5, the wires were carefully tested. An optical inspection and a spectral analysis was performed with an Environmental Scanning Electron Microscope (ESEM) to verify the composition and dimensions and the integrity of the gold plating on the surface of these wires. The spectra of the wires were studied at 10 and 30 keV. Acknowledging NSF and UIUC.

  16. Modeling of DC spacecraft power systems

    NASA Astrophysics Data System (ADS)

    Berry, F. C.

    1995-07-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  17. Modeling of DC spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Berry, F. C.

    1995-01-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  18. LANSCE Wire Scanner System Prototype: Switchyard Test

    SciTech Connect

    Sedillo, James D

    2012-04-11

    On November 19, 2011, the beam diagnostics team of Los Alamos National Laboratory's LANSCE accelerator facility conducted a test of a prototype wire scanner system for future deployment within the accelerator's switchyard area. The primary focus of this test was to demonstrate the wire scanner control system's ability to extend its functionality beyond acquiring lower energy linac beam profile measurements to acquiring data in the switchyard. This study summarizes the features and performance characteristics of the electronic and mechanical implementation of this system with details focusing on the test results.

  19. A FLYING WIRE SYSTEM IN THE AGS.

    SciTech Connect

    HUANG,H.; BUXTON,W.; MAHLER,G.; MARUSIC,A.; ROSER,T.; SMITH,G.; SYPHERS,M.; WILLIAMS,N.; WITKOVER,R.

    1999-03-29

    As the AGS prepares to serve as the injector for RHIC, monitoring and control of the beam transverse emittance become a major and important topic. Before the installation of the flying wire system, the emittance was measured with ionization profile monitors in the AGS, which require correction for space charge effects. It is desirable to have a second means of measuring profile that is less depend on intensity. A flying wire system has been installed in the AGS recently to perform this task. This paper discusses the hardware and software setup and the capabilities of the system.

  20. Development of toroid-type HTS DC reactor series for HVDC system

    NASA Astrophysics Data System (ADS)

    Kim, Kwangmin; Go, Byeong-Soo; Park, Hea-chul; Kim, Sung-kyu; Kim, Seokho; Lee, Sangjin; Oh, Yunsang; Park, Minwon; Yu, In-Keun

    2015-11-01

    This paper describes design specifications and performance of a toroid-type high-temperature superconducting (HTS) DC reactor. The first phase operation targets of the HTS DC reactor were 400 mH and 400 A. The authors have developed a real HTS DC reactor system during the last three years. The HTS DC reactor was designed using 2G GdBCO HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. The total system has been successfully developed and tested in connection with LCC type HVDC system. Now, the authors are studying a 400 mH, kA class toroid-type HTS DC reactor for the next phase research. The 1500 A class DC reactor system was designed using layered 13 mm GdBCO 2G HTS wire. The expected operating temperature is under 30 K. These fundamental data obtained through both works will usefully be applied to design a real toroid-type HTS DC reactor for grid application.

  1. Integrated Electrical Wire Insulation Repair System

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Jolley, Scott; Gibson, Tracy; Parks, Steven

    2013-01-01

    An integrated system tool will allow a technician to easily and quickly repair damaged high-performance electrical wire insulation in the field. Low-melt polyimides have been developed that can be processed into thin films that work well in the repair of damaged polyimide or fluoropolymer insulated electrical wiring. Such thin films can be used in wire insulation repairs by affixing a film of this low-melt polyimide to the damaged wire, and heating the film to effect melting, flow, and cure of the film. The resulting repair is robust, lightweight, and small in volume. The heating of this repair film is accomplished with the use of a common electrical soldering tool that has been modified with a special head or tip that can accommodate the size of wire being repaired. This repair method can furthermore be simplified for the repair technician by providing replaceable or disposable soldering tool heads that have repair film already "loaded" and ready for use. The soldering tool heating device can also be equipped with a battery power supply that will allow its use in areas where plug-in current is not available

  2. dc power system for deuteron accelerator

    SciTech Connect

    Creek, K.O.; Liska, D.J.

    1981-01-01

    The Fusion Materials Irradiation Test (FMIT) Facility dc power system provides excitation current for all linac and High-Energy Beam Transport (HEBT) quadrupole and bending magnets, excitation for horizontal and vertical beam steering, and current-bypass shunts.

  3. 49 CFR 393.28 - Wiring systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Wiring systems. 393.28 Section 393.28 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION Lamps,...

  4. A review of wiring system safety in space power systems

    NASA Technical Reports Server (NTRS)

    Stavnes, Mark W.; Hammoud, Ahmad N.

    1993-01-01

    Wiring system failures have resulted from arc propagation in the wiring harnesses of current aerospace vehicles. These failures occur when the insulation becomes conductive upon the initiation of an arc. In some cases, the conductive path of the carbon arc track displays a high enough resistance such that the current is limited, and therefore may be difficult to detect using conventional circuit protection. Often, such wiring failures are not simply the result of insulation failure, but are due to a combination of wiring system factors. Inadequate circuit protection, unforgiving system designs, and careless maintenance procedures can contribute to a wiring system failure. This paper approaches the problem with respect to the overall wiring system, in order to determine what steps can be taken to improve the reliability, maintainability, and safety of space power systems. Power system technologies, system designs, and maintenance procedures which have led to past wiring system failures will be discussed. New technologies, design processes, and management techniques which may lead to improved wiring system safety will be introduced.

  5. USAF/WL robust 300 C wire insulation system program status

    NASA Technical Reports Server (NTRS)

    Wong, Wing

    1995-01-01

    The objective of this program is to identify, develop, and demonstrate an optimum wire insulation system capable of continuous operation at 300 C which possesses a combination of superior electrical (AC or DC), mechanical, and physical properties over Kapton derived insulations described in MIL-W-81381 and those hybrid materials commonly known as TKT constructions.

  6. Anti-slipping system improves wire saw performance

    NASA Technical Reports Server (NTRS)

    Gallo, E. A.

    1971-01-01

    System prevents wire saw slippage by providing sufficient friction to turn idler spools even when turns of wire on spools do not provide sufficient friction. Low cost system is easily applied to existing equipment.

  7. Safety requirements for wiring systems and connectors for photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Lundweit, T.

    1984-09-01

    Safety requirements for wiring systems and connections and for separable connectors for use in roof mounted photovoltaic (PV) arrays were identified. The environmental use conditions applicable to PV arrays and the differences between integral, direct, standoff and rack mounted modules were considered. The articles in the national electrical code (NEC) covering wiring systems are discussed to: (1) define the wiring systems; (2) identify the permitted uses and use restrictions; (3) outline the advantages and disadvantages; and (4) address the concerns regarding support, protection against mechanical damage and wet versus dry locations. The advantages and disadvantages of each wiring system to arrive at candidate wiring systems that are best suited for use in PV arrays are assessed. For candidate wiring systems which use restrictions that may prohibit their use, considerations need to be addressed by any proposed revision to the NEC to permit acceptance by the inspection authorities. The various wiring termination methods that are permitted by the NEC are discussed and those which have features that are desirable for PV applications are identified.

  8. The dream and reality of automated wiring systems

    SciTech Connect

    Manno, R.; Dugan, D.

    1994-01-01

    This article examines the use of computer programs for automated substation/switchgear wiring in order to cut production costs associated with wiring diagrams and documentation. The topics of the article include automating the process, schematic capture editor, wiring diagram editor, design aids and documentation, display formats, and system benefits.

  9. In-Situ Wire Damage Detection System

    NASA Technical Reports Server (NTRS)

    Williams, Martha K. (Inventor); Roberson, Luke B. (Inventor); Tate, Lanetra C. (Inventor); Smith, Trent M. (Inventor); Gibson, Tracy L. (Inventor); Jolley, Scott T. (Inventor); Medelius, Pedro J. (Inventor)

    2014-01-01

    An in-situ system for detecting damage in an electrically conductive wire. The system includes a substrate at least partially covered by a layer of electrically conductive material forming a continuous or non-continuous electrically conductive layer connected to an electrical signal generator adapted to delivering electrical signals to the electrically conductive layer. Data is received and processed to identify damage to the substrate or electrically conductive layer. The electrically conductive material may include metalized carbon fibers, a thin metal coating, a conductive polymer, carbon nanotubes, metal nanoparticles or a combination thereof.

  10. Safety requirements for wiring systems and connectors for photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Lundtveit, T.

    1984-09-01

    Safety requirements for roof-mounted photovoltaic (PV) arrays were established by considering the environmental use-conditions applicable to PV arrays and the differences between integral-, direct-, standoff- and rack-mounted modules. Those articles in the National Electrical Code (NEC) covering wiring systems are discussed to: (1) define the wiring systems; (2) identify the permitted uses and use-restrictions; (3) outline the advantages and disadvantages; and (4) address the concerns regarding support, protection against mechanical damage, and wet versus dry locations. The advantages and disadvantages of each wiring system are assessed to arrive at candidate wiring systems that are best suited for use in PV arrays. For candidate wiring systems having prohibitive use-restrictions issues are considered that need to be addressed by any proposed revision to the National Electrical Code to permit acceptance by the inspection authorities. Various wiring termination methods permitted by the NEC are discussed and those which have features that are desirable for PV applications are identified. Performance and construction requirements for PV cable and for PV connectors are presented in separate outlines of proposed investigations of these products.

  11. DC side filters for multiterminal HVDC systems

    SciTech Connect

    Shore, N.L.; Adamson, K.; Bard, P.

    1996-10-01

    Multiterminal HVDC systems present challenges in the specification and design of suitable dc side filtering. This document examines the existing experience and addresses the particular technical problems posed by multiterminal systems. The filtering requirements of small taps are discussed, as is the potential use of active filters. Aspects of calculation and design are considered and recommendations made to guide the planners and designers of future multiterminal schemes.

  12. Practical dc SQUID system: Devices and electronics

    NASA Astrophysics Data System (ADS)

    Zhang, Guofeng; Zhang, Yi; Hong, Tao; Wang, Hai; Krause, Hans-Joachim; Xie, Xiaoming

    2015-11-01

    In order to set up a liquid helium-cooled practical dc SQUID system with acceptable noise figure, we employ a weakly damped dc SQUID with a large flux-to-voltage transfer coefficient ∂V/∂V in a direct readout scheme (DRS) without flux modulation. Two preamplifiers are utilized: (1) AD 797 for a so-called "single chip readout electronics" (SCRE); (2) 6 parallel-connected bipolar transistors (PCBT). The latter reduces the preamplifier voltage noise Vn but increases its current noise In, which plays a leading role in the system low-frequency noise. We introduce a current feedback circuit (CFC) consisting of an inductor Li coupled to the SQUID with mutual inductance Mi to improve the noise performance. In this work, the preamplifier In contribution and CFC are analyzed. To evaluate the In suppression with CFC, two criteria are presented. Furthermore, we establish a dimensionless parameter ξ to describe CFC quantitatively. The system noise is compared with and without CFC using the two preamplifiers. For a dc SQUID with a loop inductance of 350 pH, an intrinsic noise of about 5 μV0/√Hz and a corner frequency at 2 Hz are measured using PCBT with CFC.

  13. Evaluation of the intermittent GTA cold wire feed weld system

    SciTech Connect

    Dereskiewicz, J.P.

    1991-08-01

    An intermittent gas tungsten arc cold wire feed process was statistically evaluated to determine the feasibility of applying this process to meet the 0.030-inch weld penetration and peak temperature requirements when unfavorable joint tolerances exist on a subassembly weld. The wire feed system was determined to only slightly benefit the welding process over normal pulsed gas tungsten arc welding using traditional wire feeding capabilities. However, the complexity of this process and extensive welding operator training and qualification does not outweigh the benefits of incorporating this synchronized pulse wire feed system in production. 2 refs., 43 figs., 11 tabs.

  14. The DC-DC conversion power system of the CMS Phase-1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Schmitz, St.; Wlochal, M.

    2015-01-01

    The pixel detector of the CMS experiment will be exchanged during the year-end technical stop in 2016/2017, as part of the experiment's Phase-1 upgrade. The new device will feature approximately twice the number of readout channels, and consequently the power consumption will be doubled. By moving to a DC-DC conversion powering scheme, it is possible to power the new pixel detector with the existing power supplies and cable plant. The power system of the Phase-1 pixel detector is described and the performance of the new components, including DC-DC converters, DC-DC converter motherboards and various power distribution boards, is detailed. The outcome of system tests in terms of electrical behaviour, thermal management and pixel module performance is discussed.

  15. System and method for evaluating a wire conductor

    DOEpatents

    Panozzo, Edward; Parish, Harold

    2013-10-22

    A method of evaluating an electrically conductive wire segment having an insulated intermediate portion and non-insulated ends includes passing the insulated portion of the wire segment through an electrically conductive brush. According to the method, an electrical potential is established on the brush by a power source. The method also includes determining a value of electrical current that is conducted through the wire segment by the brush when the potential is established on the brush. The method additionally includes comparing the value of electrical current conducted through the wire segment with a predetermined current value to thereby evaluate the wire segment. A system for evaluating an electrically conductive wire segment is also disclosed.

  16. DC, AC and advanced EV propulsion systems

    SciTech Connect

    O'Neil, W.

    1983-08-01

    Battery development and liquid fuel availability and cost are still the pacing factors in wide scale electric vehicle introduction. Propulsion systems also require technical development, however, if electric vehicles are to be acceptable in the marketplace in competition against ICE vehicles. Eaton Corporation has undertaken a program designed to identify and investigate three broad types of propulsion systems in identical test vehicles on the same test track under conditions as similar as possible. Characteristics of dc, ac and advanced systems are compared to date, and projections of anticipated results and further work are provided. The compelling advantages of multiple mechanical ratios in EV propulsion systems are reviewed. An emerging, but less obvious, advantage is higher overall system efficiency.

  17. A New Flying Wire System for the Tevatron

    NASA Astrophysics Data System (ADS)

    Blokland, Willem; Dey, Joseph; Vogel, Greg

    1997-05-01

    A new Flying Wires system replaces the old system to enhance the analysis of the beam emittance, improve the reliability, and handle the upcoming upgrades of the Tevatron. New VME data acquisition modules and timing modules allow for more bunches to be sampled more precisely. The programming language LabVIEW, running on a Macintosh computer, controls the VME modules and the nuLogic motion board that flies the wires. LabVIEW also analyzes and stores the data, and handles local and remote commands. The new system flies three wires and fits profiles of 72 bunches to a gaussian function within two seconds. A new console application operates the flying wires from any control console. This paper discusses the hardware and software setup, the capabilities and measurement results of the new Flying Wires system.

  18. Simultaneous distribution of AC and DC power

    SciTech Connect

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  19. Asymmetric hysteresis loops of systems of bistable nanoscopic wires.

    PubMed

    Tomkowicz, J; González, J; Kułakowski, K

    2012-06-01

    A system of bistable magnetic nanowires of diameter D = 57 nm, length L = 115 nm, magnetization M = 370 emu/cm3 is simulated. The probability distribution of the switching fields of the wires is Gaussian, with mean Hs = 710 Oe and standard deviation u(Hs) = 105 Oe. The wires are randomly distributed on a plane, with directions parallel (OX) or perpendicular (OY) to the axis direction where the magnetic field is applied. The magnetostatic interaction between the wires leads to an asymmetry of the hysteresis loop of the system. Namely, we obtain different curves M(H) for ascending and descending magnetic field. This behaviour is due to the wires which are perpendicular to the applied magnetic field. The directions of their magnetic moments remain often unchanged during the hysteresis experiment, and their contribution to the magnetic moment measured along OX is equal to zero. However, they interact with the wires parallel to the field, and this interaction influences the magnetic state of the parallel wires. The effect can be useful when we are interested in tailoring the shape of the hysteresis loop. Also, a given magnetic configuration of the wires parallel to OY produces a unique asymmetry of the hysteresis loop of the wires parallel to OX. Once an additional field is applied along OY, this unique state is destroyed. The effect can be useful for safety systems. PMID:22905544

  20. KIM-1 interface adapter to 3-wire teletype systems

    NASA Technical Reports Server (NTRS)

    Burhans, R. W.

    1976-01-01

    The KIM-1 circuit designed for use with a full duplex isolated 4 terminal system is described. Operation of the circuit with a 3 wire system in conjunction with a single +5v supply interface is discussed.

  1. Comparison of solar panel cooling system by using dc brushless fan and dc water

    NASA Astrophysics Data System (ADS)

    Irwan, Y. M.; Leow, W. Z.; Irwanto, M.; M, Fareq; Hassan, S. I. S.; Safwati, I.; Amelia, A. R.

    2015-06-01

    The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 °C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 °C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer.

  2. Electric Field Wire Boom System and instrument for CubeSats

    NASA Astrophysics Data System (ADS)

    Stromberg, E. M.; Burr, S.; Hui, D.; Swenson, C.

    2009-12-01

    The viability of CubeSats as meaningful platforms for observing the upper atmosphere depends upon the development of suitable scientific instrumentation. One of the most fundamental parameters to observe in the space environment is the electric fields which drive the motions of the plasma in the ionosphere and magnetosphere. A well known technique for observing electric fields is the double probe with sensors deployed several meters from the space vehicle. A compact wire boom system, deploying sensors from opposite sides of a spinning CubeSat has been developed at Utah State University. We present the development of a 10 meter tip-to-tip wire boom system to deploy four 1-cm spherical double probe sensors. The wire boom mechanism consists of a spool which is actuated with a small non-magnetic, piezoelectric motor, to control deployment. The wire boom and electric field instrument is 1.25cm high and fits a standard 10 x10 cm CubeSat cross section. The spherical sensors at the end of the wire booms are gold plated to minimize geometric work function dissimilarities and to provide surface electrical stability. We present an analysis of the expected performance and lifetime of this boom in low Earth orbit. The proposed design permits the measurement of the two-dimensional DC-electric field determined only by the spacecraft velocity and the instrument sampling rate.

  3. Beam Position and Phase Monitor - Wire Mapping System

    SciTech Connect

    Watkins, Heath A; Shurter, Robert B.; Gilpatrick, John D.; Kutac, Vincent G.; Martinez, Derwin

    2012-04-10

    The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded for the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.

  4. Active dc filter for HVDC systems

    SciTech Connect

    Zhang, W. ); Asplund, G.

    1994-01-01

    This article is a case history of the installation of active dc filters for high-performance, low-cost harmonics filtering at the Lindome converter station in the Konti-Skan 2 HVDC transmission link between Denmark and Sweden. The topics of the article include harmonics, interference, and filters, Lindome active dc filter, active dc filter design, digital signal processor, control scheme, protection and fault monitoring, and future applications.

  5. Aircraft wire system laboratory development : phase I progress report.

    SciTech Connect

    Dinallo, Michael Anthony; Lopez, Christopher D.

    2003-08-01

    An aircraft wire systems laboratory has been developed to support technical maturation of diagnostic technologies being used in the aviation community for detection of faulty attributes of wiring systems. The design and development rationale of the laboratory is based in part on documented findings published by the aviation community. The main resource at the laboratory is a test bed enclosure that is populated with aged and newly assembled wire harnesses that have known defects. This report provides the test bed design and harness selection rationale, harness assembly and defect fabrication procedures, and descriptions of the laboratory for usage by the aviation community.

  6. DC isolation and protection system and circuit

    NASA Technical Reports Server (NTRS)

    Wagner, Charles A. (Inventor); Kellogg, Gary V. (Inventor)

    1991-01-01

    A precision analog electronic circuit that is capable of sending accurate signals to an external device that has hostile electric characteristics, including the presence of very large common mode voltages. The circuit is also capable of surviving applications of normal mode overvoltages of up to 120 VAC/VDC for unlimited periods of time without damage or degradation. First, the circuit isolates the DC signal output from the computer. Means are then provided for amplifying the isolated DC signal. Further means are provided for stabilizing and protecting the isolating and amplifying means, and the isolated and amplified DC signal which is output to the external device, against overvoltages and overcurrents.

  7. BAE Systems Radiation Hardened SpaceWire ASIC and Roadmap

    NASA Technical Reports Server (NTRS)

    Berger, Richard; Milliser, Myrna; Kapcio, Paul; Stanley, Dan; Moser, David; Koehler, Jennifer; Rakow, Glenn; Schnurr, Richard

    2006-01-01

    An Application Specific Integrated Circuit (ASIC) that implements the SpaceWire protocol has been developed in a radiation hardened 0.25 micron CMOS, technology. This effort began in March 2003 as a joint development between the NASA Goddard Space Flight Center (GSFC) and BAE Systems. The BAE Systems SpaceWire ASlC is comprised entirely of reusable core elements, many of which are already flight-proven. It incorporates a 4-port SpaceWire router with two local ports, dual PC1 bus interfaces, a microcontroller, 32KB of internal memory, -and a memory controller for additional external memory use. The SpaceWire ASlC is planned for use on both the Geostationary Operational Environmental Satellites (GOES)-R and the Lunar Reconnaissance Orbiter (LRO). Engineering parts have already been delivered to both programs. This paper discusses the SpaceWire protocol and those elements of it that have been built into the current SpaceWire reusable core. There are features within the core that go beyond the current standard that can be enabled or disabled by the user and these will be described. The adaptation of SpaceWire to BAE Systems' On Chip Bus (OCB) for compatibility with the other reusable cores will be discussed. Optional configurations within user systems will be shown. The physical imp!ementation of the design will be described and test results from the hardware will be discussed. Finally, the BAE Systems roadmap for SpaceWire developments will be discussed, including some products already in design as well as longer term plans.

  8. Differential Power Processing for DC Systems

    SciTech Connect

    Shenoy, PS; Krein, PT

    2013-04-01

    This paper introduces an approach to dc power delivery that reduces power loss by minimizing redundant energy conversion. Existing power distribution techniques tend to increase the number of cascaded conversion stages, which limits overall efficiency. Differential power processing enables independent load regulation, while processing only a small portion of the total load power. Bulk power conversion occurs once. Load voltage domains are connected in series, and differential converters act as controllable current sources to regulate intermediate nodes. This enables independent, low supply voltages, which can reduce system energy consumption, especially in digital circuits and solid-state lighting. Since differential voltage regulators process a fraction of the load power, decreased size, cost, and conversion losses are attainable. Under balanced load conditions, secondary differential converters do not process any power. This paper analyzes several differential power delivery architectures that can be applied to homogenous and heterogeneous loads at various levels: chip, board, blade, etc. A variety of operating conditions for a test system with four series voltage domains are examined in simulation and verified with experimental hardware. Results in a reference application show a 7-8% decrease in input power and 6-7 percentage points increase in overall conversion efficiency as compared to a conventional cascaded approach.

  9. Ferrite insertion at Recycler Flying Wire System

    SciTech Connect

    K.Y. Ng

    2004-02-27

    Ferrite rods are installed inside the flying-wire cavity of the Recycler Ring and at entrance and exit beam pipes in order to absorb high-frequency electromagnetic waves excited by the beam. However, these rods may also deteriorate the vacuum pressure of the ring. An investigation is made to analyze the necessity of the ferrite rods at the entrance and exit beam pipes.

  10. SNS LINAC Wire Scanner System : Signal Levels and Accuracy.

    SciTech Connect

    Plum, M. A.; Christensen, W.; Myer, R. E.; Rose, C. R.

    2002-01-01

    The linac wire scanner system for the Spallation Neutron Source (SNS) at Oak Ridge, TN, USA, calls for 5 units in the medium energy beam transport (MEBT), 5 in the drift tube linac (DTL), and 10 in the coupled cavity linac (CCL). In this paper we present expected signal levels and an analysis of the error in the beam size measurement as functions of wire position and electrical signal errors.

  11. New solar cell power supply system using a boost type bidirectional dc-dc converter

    NASA Astrophysics Data System (ADS)

    Matsuo, H.; Kurokawa, F.

    New solar cell power supply system is presented, in which the boost type bidirectional dc-dc converter and the simple control circuit with a small monitor solar cell are employed to track the maximum power point of the solar array. It is confirmed by the experiment that the new system has the sufficiently precise tracking operation performance and the satisfactorily high power efficiency. Also, a comparison of the power efficiencies is made with theoretically as well as experimentally on the new and the conventional solar cell power supply systems. As a result, it is revealed that the new system is superior to the conventional one in the power efficiency.

  12. A Laser-Wire System at the ATF Extraction Line

    SciTech Connect

    Boogert, S.T.; Blair, G.; Boorman, G.; Bosco, A.; Deacon, L.; Driouichi, C.; Karataev, P.; Kamps, T.; Delerue, N.; Dixit, S.; Foster, B.; Gannaway, F.; Howell, D.F.; Qureshi, M.; Reichold, A.; Senanayake, R.; Aryshev, A.; Hayano, H.; Kubo, K.; Terunuma, N.; Urakawa, J.; /KEK, Tsukuba /Liverpool U. /Cockcroft Inst. Accel. Sci. Tech. /SLAC

    2007-02-12

    A new laser-wire (LW) system has been installed at the ATF extraction line at KEK, Tsukuba. The system aims at a micron-scale laser spot size and employs a mode-locked laser system. The purpose-built interaction chamber, light delivery optics, and lens systems are described, and the first results are presented.

  13. Operational environments for electrical power wiring on NASA space systems

    NASA Technical Reports Server (NTRS)

    Stavnes, Mark W.; Hammoud, Ahmad N.; Bercaw, Robert W.

    1994-01-01

    Electrical wiring systems are used extensively on NASA space systems for power management and distribution, control and command, and data transmission. The reliability of these systems when exposed to the harsh environments of space is very critical to mission success and crew safety. Failures have been reported both on the ground and in flight due to arc tracking in the wiring harnesses, made possible by insulation degradation. This report was written as part of a NASA Office of Safety and Mission Assurance (Code Q) program to identify and characterize wiring systems in terms of their potential use in aerospace vehicles. The goal of the program is to provide the information and guidance needed to develop and qualify reliable, safe, lightweight wiring systems, which are resistant to arc tracking and suitable for use in space power applications. This report identifies the environments in which NASA spacecraft will operate, and determines the specific NASA testing requirements. A summary of related test programs is also given in this report. This data will be valuable to spacecraft designers in determining the best wiring constructions for the various NASA applications.

  14. Operational environments for electrical power wiring on NASA space systems

    NASA Astrophysics Data System (ADS)

    Stavnes, Mark W.; Hammoud, Ahmad N.; Bercaw, Robert W.

    1994-06-01

    Electrical wiring systems are used extensively on NASA space systems for power management and distribution, control and command, and data transmission. The reliability of these systems when exposed to the harsh environments of space is very critical to mission success and crew safety. Failures have been reported both on the ground and in flight due to arc tracking in the wiring harnesses, made possible by insulation degradation. This report was written as part of a NASA Office of Safety and Mission Assurance (Code Q) program to identify and characterize wiring systems in terms of their potential use in aerospace vehicles. The goal of the program is to provide the information and guidance needed to develop and qualify reliable, safe, lightweight wiring systems, which are resistant to arc tracking and suitable for use in space power applications. This report identifies the environments in which NASA spacecraft will operate, and determines the specific NASA testing requirements. A summary of related test programs is also given in this report. This data will be valuable to spacecraft designers in determining the best wiring constructions for the various NASA applications.

  15. Wired.

    ERIC Educational Resources Information Center

    Conklin, Aaron R.

    1998-01-01

    Discusses technology's impact on scoreboard design: the development of the light-emitting diode (LED) display. How the LED system works is explained, as are the advantages and disadvantages of LED compared with incandescent lamp boards. Final comments address deciding on materials for scoreboard casings. (GR)

  16. Risk management in fly-by-wire systems

    NASA Technical Reports Server (NTRS)

    Knoll, Karyn T.

    1993-01-01

    A general description of various types of fly-by-wire systems is provided. The risks inherent in digital flight control systems, like those used in the Space Shuttle, are identified. The results of a literature survey examining risk management methods in use throughout the aerospace industry are presented. The applicability of these methods to the Space Shuttle program is discussed.

  17. dc: a live Webcast control system

    NASA Astrophysics Data System (ADS)

    Yu, Tai-Ping; Wu, David; Mayer-Patel, Ketan D.; Rowe, Lawrence A.

    2000-12-01

    Live Internet streaming media programs, called webcasts, can adopt techniques developed by television to obtain higher quality. We have developed a general webcast production model composed of three stages (i.e., sources, broadcast, and transmission) and a tool, called the Director's Console (dc), to control live webcasts. The tool is one component of a distributed service architecture, which adapts to varying physical infrastructure and broadcast configurations.

  18. Suppression Method for Harmonic Magnification of DC Circuit in Large-Scale Inverter System

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Ikuo; Okui, Akinobu; Matsuse, Kouki

    In a large-scale inverter system that uses a semiconductor switching device, a rectifier and an inverter are connected through a DC circuit. In this circuit, the harmonic magnification phenomenon is often induced by the inductance of distribution wires and the condenser to absorb the harmonic voltage and current. To suppress this harmonic magnification phenomenon, we propose a new suppression method to use the initial phase of the carrier wave. When some inverters operate in parallel at the same frequency, such as the inverters to drive LSM, it is possible to reduce the specific harmonic component of the total inverter input current due to PWM control by changing the phase of the carrier wave of each inverter. We studied a method of suppressing the magnification phenomenon of the specific harmonic near the resonant frequency of the DC circuit by using this principle and confirmed its performance by the digital simulation.

  19. DC motor proportional control system for orthotic devices

    NASA Technical Reports Server (NTRS)

    Blaise, H. T.; Allen, J. R.

    1972-01-01

    Multi-channel proportional control system for operation of dc motors for use with externally-powered orthotic arm braces is described. Components of circuitry and principles of operation are described. Schematic diagram of control circuit is provided.

  20. Semiautomatic cold wire feeder systems increase GTA productivity

    SciTech Connect

    Richardson, M. )

    1995-01-01

    Often, the focus of attempts to increase GTA welding productivity is on studies to determine if justification exists for additional workstations, or for the investment in new fully automated dedicated welding fixtures. Often less costly and simpler solutions can bring about the necessary means to increase production rates and reduce operating costs. For short-run production applications, it is almost impossible to justify the substantial investment in a dedicated automatic fixture. Now, low cost GTA cold wire feeder systems are within the reach of even small shops. The paper views how cold wire equipment has been applied in several GTAW applications to improve results.

  1. Development of a Production Ready Automated Wire Delivery System

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The current development effort is a Phase 3 research study entitled "A Production Ready Automated Wire Delivery System", contract number NAS8-39933, awarded to Nichols Research Corporation (NRC). The goals of this research study were to production harden the existing Automated Wire Delivery (AWDS) motion and sensor hardware and test the modified AWDS in a range of welding applications. In addition, the prototype AWDS controller would be moved to the VME bus platform by designing, fabricating and testing a single board VME bus AWDS controller. This effort was to provide an AWDS that could transition from the laboratory environment to production operations. The project was performed in two development steps. Step 1 modified and tested an improved MWG. Step 2 developed and tested the AWDS single board VME bus controller. Step 3 installed the Wire Pilot in a Weld Controller with the imbedded VME bus controller.

  2. NASA/BAE SYSTEMS SpaceWire Effort

    NASA Technical Reports Server (NTRS)

    Rakow, Glenn Parker; Schnurr, Richard G.; Kapcio, Paul

    2003-01-01

    This paper discusses the state of the NASA and BAE SYSTEMS developments of SpaceWire. NASA has developed intellectual property that implements SpaceWire in Register Transfer Level (RTL) VHDL for a SpaceWire link and router. This design has been extensively verified using directed tests from the SpaceWire Standard and design specification, as well as being randomly tested to flush out hard to find bugs in the code. The high level features of the design will be discussed, including the support for multiple time code masters, which will be useful for the James Webb Space Telescope electrical architecture. This design is now ready to be targeted to FPGA's and ASICs. Target utilization and performance information will be presented for Spaceflight worthy FPGA's and a discussion of the ASIC implementations will be addressed. In particular, the BAE SYSTEMS ASIC will be highlighted which will be implemented on their .25micron rad-hard line. The chip will implement a 4-port router with the ability to tie chips together to make larger routers without external glue logic. This part will have integrated LVDS drivers/receivers, include a PLL and include skew control logic. It will be targeted to run at greater than 300 MHz and include the implementation for the proposed SpaceWire transport layer. The need to provide a reliable transport mechanism for SpaceWire has been identified by both NASA And ESA, who are attempting to define a transport layer standard that utilizes a low overhead, low latency connection oriented approach that works end-to-end. This layer needs to be implemented in hardware to prevent bottlenecks.

  3. Mechanical Backup For Fly-By-Wire Control System

    NASA Technical Reports Server (NTRS)

    Stewart, Eric C.

    1992-01-01

    Mechanical device eliminates need for redundant fly-by-wire subsystems. Main components are two linkages. One connected to control column in conventional, reversible control system. Other slides inside first linkage and connected to pilot's control wheel. In addition to aircraft applications, design used in control systems in which computer control desirable but safety backup systems required; for example, in boat rudders, engine controls in boats and automobiles, and controls in construction equipment.

  4. Commissioning a Vibrating Wire System for Quadrupole Fiducialization

    SciTech Connect

    Levashov, Michael Y

    2010-12-03

    Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of the quadrupoles. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing such a system. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). A previous study investigated the error associated with each step by using a permanent quadrupole magnet on an optical mover system. The study reported an error of 11{micro}m for step 1 and a repeatability of 4{micro}m for step 2. However, the set up used a FARO arm to measure tooling balls and didn't allow to accurately check step 2 for errors; an uncertainty of 100{micro}m was reported. Therefore, even though the repeatability was good, there was no way to check that the error in step 2 was small. Following the recommendations of that study, we used a CMM (Coordinate Measuring Machine) instead of the FARO arm for measuring the tooling balls. In addition, a roller cam positioner system replaced the optical movers for moving the quadrupole. With the exception of the quadrupole itself, the system was identical to what will be used in fiducializing the undulator quadrupoles. In this study, we investigate the new vibrating wire set up, including the error associated with each step of fiducialization. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note is a continuation of previous work to study the ability of the system to fulfill the fiducialization requirements.

  5. Crossed hot-wire data acquisition and reduction system

    NASA Technical Reports Server (NTRS)

    Westphal, R. V.; Mehta, R. D.

    1984-01-01

    The report describes a system for rapid computerized calibration acquisition, and processing of data from a crossed hot-wire anemometer is described. Advantages of the system are its speed, minimal use of analog electronics, and improved accuracy of the resulting data. Two components of mean velocity and turbulence statistics up to third order are provided by the data reduction. Details of the hardware, calibration procedures, response equations, software, and sample results from measurements in a turbulent plane mixing layer are presented.

  6. Photovoltaic-wind hybrid system for permanent magnet DC motor

    NASA Astrophysics Data System (ADS)

    Nasir, M. N. M.; Lada, M. Y.; Baharom, M. F.; Jaafar, H. I.; Ramani, A. N.; Sulaima, M. F.

    2015-05-01

    Hybrid system of Photovoltaic (PV) - Wind turbine (WT) generation has more advantages and reliable compared to PV or wind turbine system alone. The aim of this paper is to model and design hybrid system of PV-WT supplying 100W permanent-magnet dc motor. To achieve the objective, both of PV and WT are connected to converter in order to get the same source of DC supply. Then both sources were combined and straightly connected to 100W permanent magnet dc motor. All the works in this paper is only applied in circuit simulator by using Matlab Simulink. The output produced from each converter is expected to be suit to the motor specification. The output produced from each renewable energy system is as expected to be high as it can support the motor if one of them is breakdown

  7. A framework for SFC/DC system data analysis

    NASA Technical Reports Server (NTRS)

    Centeno, Martha A.

    1993-01-01

    The Shop Floor Control/Data Collection (SFC/DC) system is one of four major modules of the Integrated Work Control System being implemented at the NASA Kennedy Space Center. The SFC/DC system, which has been in operation approximately one and a half years, collects detailed information regarding the duration of tasks as well as work stoppages duration. This information needs to be effectively analyzed, so as be able to manage the shuttle processing activities under the continuous improvement philosophy. We have studied the contents and form of the SFC/DC database, and based on the results of such study, we have designed a Shop floor Modeling, Analysis, and Reporting Tool (SMART). SMART is a collection of compatible tools (off-the-shelf as well as customized C-based tools) that work cohesively to prepare inputs for the analysis models and process the various models. The feasibility of SMART has been demonstrated through an initial prototype.

  8. Fly-by-Wire Systems Enable Safer, More Efficient Flight

    NASA Technical Reports Server (NTRS)

    2012-01-01

    Using the ultra-reliable Apollo Guidance Computer that enabled the Apollo Moon missions, Dryden Flight Research Center engineers, in partnership with industry leaders such as Cambridge, Massachusetts-based Draper Laboratory, demonstrated that digital computers could be used to fly aircraft. Digital fly-by-wire systems have since been incorporated into large airliners, military jets, revolutionary new aircraft, and even cars and submarines.

  9. Operating characteristic analysis of a 400 mH class HTS DC reactor in connection with a laboratory scale LCC type HVDC system

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Kyu; Kim, Kwangmin; Park, Minwon; Yu, In-Keun; Lee, Sangjin

    2015-11-01

    High temperature superconducting (HTS) devices are being developed due to their advantages. Most line commutated converter based high voltage direct current (HVDC) transmission systems for long-distance transmission require large inductance of DC reactor; however, generally, copper-based reactors cause a lot of electrical losses during the system operation. This is driving researchers to develop a new type of DC reactor using HTS wire. The authors have developed a 400 mH class HTS DC reactor and a laboratory scale test-bed for line-commutated converter type HVDC system and applied the HTS DC reactor to the HVDC system to investigate their operating characteristics. The 400 mH class HTS DC reactor is designed using a toroid type magnet. The HVDC system is designed in the form of a mono-pole system with thyristor-based 12-pulse power converters. In this paper, the investigation results of the HTS DC reactor in connection with the HVDC system are described. The operating characteristics of the HTS DC reactor are analyzed under various operating conditions of the system. Through the results, applicability of an HTS DC reactor in an HVDC system is discussed in detail.

  10. Electrohydrodynamic force produced by a wire-to-cylinder dc corona discharge in air at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Moreau, Eric; Benard, Nicolas; Lan-Sun-Luk, Jean-Daniel; Chabriat, Jean-Pierre

    2013-11-01

    Wire-to-cylinder corona discharges are studied to better understand the electrohydrodynamic (EHD) phenomena that govern the performances of electric propulsion systems. First, theory associated with EHD thrusters is presented in order to be compared with experimental results. Secondly, direct thrust measurements are carried out to optimize the electrical and geometrical parameters of such devices. The main results are as follows: (1) the discharge current I is proportional to the square root of the grounded electrode diameter and to 1/d2 where d is the electrode gap; (2) for d ⩽ 20 mm, the mobility of negative ions is higher than that of positive ions while the mobility of both ions is equal for higher gaps; (3) therefore, for gap ⩾30 mm, positive and negative coronas results in the same current-to-thrust conversion; (4) the current-to-thrust conversion is equal to 33 N A-1 per centimetre of gap, and it is proportional to the gap; (5) the thruster effectiveness θ increases with \\sqrt d , decreases with the square root of thrust and reaches about 15 N kW-1 for d = 40 mm (6) the force computed from experimental velocity profiles is overestimated compared with the values measured with a balance, showing that this method cannot be used for thrust determination.

  11. AC/DC Power Systems with Applications for future Lunar/Mars base and Crew Exploration Vehicle

    NASA Technical Reports Server (NTRS)

    Chowdhury, Badrul H.

    2005-01-01

    ABSTRACT The Power Systems branch at JSC faces a number of complex issues as it readies itself for the President's initiative on future space exploration beyond low earth orbit. Some of these preliminary issues - those dealing with electric power generation and distribution on board Mars-bound vehicle and that on Lunar and Martian surface may be summarized as follows: Type of prime mover - Because solar power may not be readily available on parts of the Lunar/Mars surface and also during the long duration flight to Mars, the primary source of power will most likely be nuclear power (Uranium fuel rods) with a secondary source of fuel cell (Hydrogen supply). The electric power generation source - With nuclear power being the main prime mover, the electric power generation source will most likely be an ac generator at a yet to be determined frequency. Thus, a critical issue is whether the generator should generate at constant or variable frequency. This will decide what type of generator to use - whether it is a synchronous machine, an asynchronous induction machine or a switched reluctance machine. The type of power distribution system - the distribution frequency, number of wires (3- wire, 4-wire or higher), and ac/dc hybridization. Building redundancy and fault tolerance in the generation and distribution sub-systems so that the system is safe; provides 100% availability to critical loads; continues to operate even with faulted sub-systems; and requires minimal maintenance. This report descril_es results of a summer faculty fellowship spent in the Power Systems Branch with the specific aim of investigating some of the lessons learned in electric power generation and usage from the terrestrial power systems industry, the aerospace industry as well as NASA's on-going missions so as to recommend novel surface and vehicle-based power systems architectures in support of future space exploration initiatives. A hybrid ac/dc architecture with source side and load side redundancies and including emergency generators on both ac and dc sides is proposed. The generation frequency is 400 Hz mostly because of the technology maturity at this frequency in the aerospace industry. Power will be distributed to several ac load distribution buses through solid state variable speed, constant frequency converters on the ac side. A segmented dc ring bus supplied from ac/dc converters and with the capability of connecting/disconnecting the segments will supply power to multiple de load distribution buses. The system will have the capability of reverse flow from dc to ac side in the case of an extreme emergency on the main ac generation side.

  12. System For Characterizing Three-Phase Brushless dc Motors

    NASA Technical Reports Server (NTRS)

    Howard, David E.; Smith, Dennis A.

    1996-01-01

    System of electronic hardware and software developed to automate measurements and calculations needed to characterize electromechanical performances of three-phase brushless dc motors, associated shaft-angle sensors needed for commutation, and associated brushless tachometers. System quickly takes measurements on all three phases of motor, tachometer, and shaft-angle sensor simultaneously and processes measurements into performance data. Also useful in development and testing of motors with not only three phases but also two, four, or more phases.

  13. DC link stabilized field oriented control of electric propulsion systems

    SciTech Connect

    Sudhoff, S.D.; Corzine, K.A.; Glover, S.F.; Hegner, H.J.; Robey, H.N. Jr.

    1998-03-01

    Induction motor based electric propulsion systems can be used in a wide variety of applications including locomotives, hybrid electric vehicles, and ships. Field oriented control of these drives is attractive since it allows the torque to be tightly and nearly instantaneously controlled. However, such systems can be prone to negative impedance instability of the DC link. This paper examines this type of instability and sets forth a readily implemented albeit nonlinear control strategy to mitigate this potential problem.

  14. Carbon-atom wires: 1-D systems with tunable properties.

    PubMed

    Casari, C S; Tommasini, M; Tykwinski, R R; Milani, A

    2016-02-18

    This review provides a discussion of the current state of research on linear carbon structures and related materials based on sp-hybridization of carbon atoms (polyynes and cumulenes). We show that such systems have widely tunable properties and thus represent an intriguing and mostly unexplored field for both fundamental and applied sciences. We discuss the rich interplay between the structural, vibrational, and electronic properties focusing on recent advances and the future perspectives of carbon-atom wires and novel hybrid sp-sp(2)-carbon architectures. PMID:26847474

  15. Carbon-atom wires: 1-D systems with tunable properties

    NASA Astrophysics Data System (ADS)

    Casari, C. S.; Tommasini, M.; Tykwinski, R. R.; Milani, A.

    2016-02-01

    This review provides a discussion of the current state of research on linear carbon structures and related materials based on sp-hybridization of carbon atoms (polyynes and cumulenes). We show that such systems have widely tunable properties and thus represent an intriguing and mostly unexplored field for both fundamental and applied sciences. We discuss the rich interplay between the structural, vibrational, and electronic properties focusing on recent advances and the future perspectives of carbon-atom wires and novel hybrid sp-sp2-carbon architectures.

  16. Electrostatic coalescence system with independent AC and DC hydrophilic electrodes

    DOEpatents

    Hovarongkura, A. David; Henry, Jr., Joseph D.

    1981-01-01

    An improved electrostatic coalescence system is provided in which independent AC and DC hydrophilic electrodes are employed to provide more complete dehydration of an oil emulsion. The AC field is produced between an AC electrode array and the water-oil interface wherein the AC electrode array is positioned parallel to the interface which acts as a grounded electrode. The emulsion is introduced into the AC field in an evenly distributed manner at the interface. The AC field promotes drop-drop and drop-interface coalescence of the water phase in the entering emulsion. The continuous oil phase passes upward through the perforated AC electrode array and enters a strong DC field produced between closely spaced DC electrodes in which small dispersed droplets of water entrained in the continuous phase are removed primarily by collection at hydrophilic DC electrodes. Large droplets of water collected by the electrodes migrate downward through the AC electrode array to the interface. All phase separation mechanisms are utilized to accomplish more complete phase separation.

  17. Novel calibration system with sparse wires for CMB polarization receivers

    SciTech Connect

    Tajima, O.; Nguyen, H.; Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

    2011-07-01

    B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

  18. Novel Calibration System with Sparse Wires for CMB Polarization Receivers

    NASA Astrophysics Data System (ADS)

    Tajima, O.; Nguyen, H.; Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A.

    2012-06-01

    A curl competent (also known as B-modes) in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate "simultaneously" all detectors on the large focal plane. We developed a novel calibration system that rotates a large "sparse" grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature photons from the wire surface. Since the detector has a finite beam size, the observed signal is convolved with the beam property. The intensity of the of the calibrator is reasonable (a few Kelvin or less) compared to sky temperature for typical observing conditions (˜10 K). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

  19. CydDC-mediated reductant export in Escherichia coli controls the transcriptional wiring of energy metabolism and combats nitrosative stress.

    PubMed

    Holyoake, Louise V; Hunt, Stuart; Sanguinetti, Guido; Cook, Gregory M; Howard, Mark J; Rowe, Michelle L; Poole, Robert K; Shepherd, Mark

    2016-03-15

    The glutathione/cysteine exporter CydDC maintains redox balance in Escherichia coli. A cydD mutant strain was used to probe the influence of CydDC upon reduced thiol export, gene expression, metabolic perturbations, intracellular pH homoeostasis and tolerance to nitric oxide (NO). Loss of CydDC was found to decrease extracytoplasmic thiol levels, whereas overexpression diminished the cytoplasmic thiol content. Transcriptomic analysis revealed a dramatic up-regulation of protein chaperones, protein degradation (via phenylpropionate/phenylacetate catabolism), β-oxidation of fatty acids and genes involved in nitrate/nitrite reduction. (1)H NMR metabolomics revealed elevated methionine and betaine and diminished acetate and NAD(+) in cydD cells, which was consistent with the transcriptomics-based metabolic model. The growth rate and ΔpH, however, were unaffected, although the cydD strain did exhibit sensitivity to the NO-releasing compound NOC-12. These observations are consistent with the hypothesis that the loss of CydDC-mediated reductant export promotes protein misfolding, adaptations to energy metabolism and sensitivity to NO. The addition of both glutathione and cysteine to the medium was found to complement the loss of bd-type cytochrome synthesis in a cydD strain (a key component of the pleiotropic cydDC phenotype), providing the first direct evidence that CydDC substrates are able to restore the correct assembly of this respiratory oxidase. These data provide an insight into the metabolic flexibility of E. coli, highlight the importance of bacterial redox homoeostasis during nitrosative stress, and report for the first time the ability of periplasmic low molecular weight thiols to restore haem incorporation into a cytochrome complex. PMID:26699904

  20. CydDC-mediated reductant export in Escherichia coli controls the transcriptional wiring of energy metabolism and combats nitrosative stress

    PubMed Central

    Holyoake, Louise V.; Hunt, Stuart; Sanguinetti, Guido; Cook, Gregory M.; Howard, Mark J.; Rowe, Michelle L.; Poole, Robert K.; Shepherd, Mark

    2015-01-01

    The glutathione/cysteine exporter CydDC maintains redox balance in Escherichia coli. A cydD mutant strain was used to probe the influence of CydDC upon reduced thiol export, gene expression, metabolic perturbations, intracellular pH homoeostasis and tolerance to nitric oxide (NO). Loss of CydDC was found to decrease extracytoplasmic thiol levels, whereas overexpression diminished the cytoplasmic thiol content. Transcriptomic analysis revealed a dramatic up-regulation of protein chaperones, protein degradation (via phenylpropionate/phenylacetate catabolism), β-oxidation of fatty acids and genes involved in nitrate/nitrite reduction. 1H NMR metabolomics revealed elevated methionine and betaine and diminished acetate and NAD+ in cydD cells, which was consistent with the transcriptomics-based metabolic model. The growth rate and ΔpH, however, were unaffected, although the cydD strain did exhibit sensitivity to the NO-releasing compound NOC-12. These observations are consistent with the hypothesis that the loss of CydDC-mediated reductant export promotes protein misfolding, adaptations to energy metabolism and sensitivity to NO. The addition of both glutathione and cysteine to the medium was found to complement the loss of bd-type cytochrome synthesis in a cydD strain (a key component of the pleiotropic cydDC phenotype), providing the first direct evidence that CydDC substrates are able to restore the correct assembly of this respiratory oxidase. These data provide an insight into the metabolic flexibility of E. coli, highlight the importance of bacterial redox homoeostasis during nitrosative stress, and report for the first time the ability of periplasmic low molecular weight thiols to restore haem incorporation into a cytochrome complex. PMID:26699904

  1. A wire scanner system for characterizing the BNL energy recovery LINAC beam position monitor system

    SciTech Connect

    Michnoff R.; Biscardi, C.; Cerniglia, P.; Degen, C.; Gassner, D.; Hoff, L.; Hulsart, R.

    2012-04-15

    A stepper motor controlled wire scanner system has recently been modified to support testing of the Brookhaven National Laboratory (BNL) Collider-Accelerator department's Energy Recovery Linac (ERL) beam position monitor (BPM) system. The ERL BPM consists of four 9.33 mm diameter buttons mounted at 90 degree spacing in a cube with 1.875 inch inside diameter. The buttons were designed by BNL and fabricated by Times Microwave Systems. Libera brilliance single pass BPM electronic modules with 700 MHz bandpass filter, manufactured by Instrumentation Technologies, will be used to measure the transverse beam positions at 14 locations around the ERL. The wire scanner assembly provides the ability to measure the BPM button response to a pulsed wire, and evaluate and calibrate the Libera position measurement electronics. A description of the wire scanner system and test result data will be presented.

  2. Multi-kw dc power distribution system study program

    NASA Technical Reports Server (NTRS)

    Berkery, E. A.; Krausz, A.

    1974-01-01

    The first phase of the Multi-kw dc Power Distribution Technology Program is reported and involves the test and evaluation of a technology breadboard in a specifically designed test facility according to design concepts developed in a previous study on space vehicle electrical power processing, distribution, and control. The static and dynamic performance, fault isolation, reliability, electromagnetic interference characterisitics, and operability factors of high distribution systems were studied in order to gain a technology base for the use of high voltage dc systems in future aerospace vehicles. Detailed technical descriptions are presented and include data for the following: (1) dynamic interactions due to operation of solid state and electromechanical switchgear; (2) multiplexed and computer controlled supervision and checkout methods; (3) pulse width modulator design; and (4) cable design factors.

  3. Active disturbance rejection control in steering by wire haptic systems.

    PubMed

    Rodriguez-Angeles, A; Garcia-Antonio, J A

    2014-07-01

    This paper introduces a steering by wired haptic system based on disturbance rejection control techniques. High gain Generalized Proportional Integral (GPI) observers are considered for the estimation of tire and steering wheel dynamic disturbances. These disturbances are on line canceled to ensure tracking between the commanded steering wheel angle and the tire orientation angle. The estimated disturbances at the steering rack are feedback to the steering wheel to provide a haptic interface with the driver. The overall system behaves as a bilateral master-slave system. Very few sensors and minimum knowledge of the dynamic model are required. Experimental results are presented on a prototype platform that consists on: (1) half of the steering rack of a beetle VW vehicle, (2) a steering wheel. PMID:23978660

  4. NASA/Ames Research Center DC-8 data system

    NASA Technical Reports Server (NTRS)

    Cherniss, S. C.; Scofield, C. P.

    1991-01-01

    In-flight facility data acquisition, distribution, and recording on the NASA Ames Research Center (ARC) DC-8 are performed by the Data Acquisition and Distribution System (DADS). Navigational and environmental data collected by the DADS are converted to engineering units and distributed real-time to investigator stations once per second. Selected engineering units data are printed and displayed on closed circuit television monitors throughout flights. An in-flight graphical display of the DC-8 flight track (with barbs indicating wind direction and magnitude) has recently been added to the DADS capabilities. Logging of data run starts/stops and commentary from the mission director are also provided. All data are recorded to hard disk in-flight and archived to tape medium post-flight. Post-flight, hard copies of the track map and mission director's log are created by the DADS. The DADS is a distributed system consisting of a data subsystem, an Avionic Serial Data-to-VMEbus (ASD2VME) subsystem, and a host subsystem. Each subsystem has a dedicated central processing unit (CPU) and is capable of stand-alone operation. All three subsystems are housed in a single 20-slot VME chassis and communicate with each other over the VMEbus. The data and host subsystems are briefly discussed, and the DC-8 DADS internal configuration and system block diagram are presented.

  5. Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System

    ERIC Educational Resources Information Center

    Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

    2012-01-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders

  6. Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System

    ERIC Educational Resources Information Center

    Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

    2012-01-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

  7. DC Bus Regulation with a Flywheel Energy Storage System

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Kascak, Peter E.

    2003-01-01

    This paper describes the DC bus regulation control algorithm for the NASA flywheel energy storage system during charge, charge reduction and discharge modes of operation. The algorithm was experimentally verified with results given in a previous paper. This paper presents the necessary models for simulation with detailed block diagrams of the controller algorithm. It is shown that the flywheel system and the controller can be modeled in three levels of detail depending on the type of analysis required. The three models are explained and then compared using simulation results.

  8. 14 CFR 26.11 - Electrical wiring interconnection systems (EWIS) maintenance program.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Electrical wiring interconnection systems (EWIS) maintenance program. 26.11 Section 26.11 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... AIRPLANES Enhanced Airworthiness Program for Airplane Systems § 26.11 Electrical wiring...

  9. 14 CFR 26.11 - Electrical wiring interconnection systems (EWIS) maintenance program.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Electrical wiring interconnection systems (EWIS) maintenance program. 26.11 Section 26.11 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... AIRPLANES Enhanced Airworthiness Program for Airplane Systems § 26.11 Electrical wiring...

  10. Efficient Design in a DC to DC Converter Unit

    NASA Technical Reports Server (NTRS)

    Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.

    2002-01-01

    Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.

  11. Multi-KW dc distribution system technology research study

    NASA Technical Reports Server (NTRS)

    Dawson, S. G.

    1978-01-01

    The Multi-KW DC Distribution System Technology Research Study is the third phase of the NASA/MSFC study program. The purpose of this contract was to complete the design of the integrated technology test facility, provide test planning, support test operations and evaluate test results. The subjet of this study is a continuation of this contract. The purpose of this continuation is to study and analyze high voltage system safety, to determine optimum voltage levels versus power, to identify power distribution system components which require development for higher voltage systems and finally to determine what modifications must be made to the Power Distribution System Simulator (PDSS) to demonstrate 300 Vdc distribution capability.

  12. Development of a DC propulsion system for an electric vehicle

    NASA Technical Reports Server (NTRS)

    Kelledes, W. L.

    1984-01-01

    The suitability of the Eaton automatically shifted mechanical transaxle concept for use in a near-term dc powered electric vehicle is evaluated. A prototype dc propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the contractor's site. The system consisted of a two-axis, three-speed, automatically-shifted mechanical transaxle, 15.2 Kw rated, separately excited traction motor, and a transistorized motor controller with a single chopper providing limited armature current below motor base speed and full range field control above base speed at up to twice rated motor current. The controller utilized a microprocessor to perform motor and vehicle speed monitoring and shift sequencing by means of solenoids applying hydraulic pressure to the transaxle clutches. Bench dynamometer and track testing was performed. Track testing showed best system efficiency for steady-state cruising speeds of 65-80 Km/Hz (40-50 mph). Test results include acceleration, steady speed and SAE J227A/D cycle energy consumption, braking tests and coast down to characterize the vehicle road load.

  13. X-wing fly-by-wire vehicle management system

    NASA Technical Reports Server (NTRS)

    Fischer, Jr., William C. (Inventor)

    1990-01-01

    A complete, computer based, vehicle management system (VMS) for X-Wing aircraft using digital fly-by-wire technology controlling many subsystems and providing functions beyond the classical aircraft flight control system. The vehicle management system receives input signals from a multiplicity of sensors and provides commands to a large number of actuators controlling many subsystems. The VMS includes--segregating flight critical and mission critical factors and providing a greater level of back-up or redundancy for the former; centralizing the computation of functions utilized by several subsystems (e.g. air data, rotor speed, etc.); integrating the control of the flight control functions, the compressor control, the rotor conversion control, vibration alleviation by higher harmonic control, engine power anticipation and self-test, all in the same flight control computer (FCC) hardware units. The VMS uses equivalent redundancy techniques to attain quadruple equivalency levels; includes alternate modes of operation and recovery means to back-up any functions which fail; and uses back-up control software for software redundancy.

  14. Virtual Instrument Systems in Reality (VISIR) for Remote Wiring and Measurement of Electronic Circuits on Breadboard

    ERIC Educational Resources Information Center

    Tawfik, M.; Sancristobal, E.; Martin, S.; Gil, R.; Diaz, G.; Colmenar, A.; Peire, J.; Castro, M.; Nilsson, K.; Zackrisson, J.; Hakansson, L.; Gustavsson, I.

    2013-01-01

    This paper reports on a state-of-the-art remote laboratory project called Virtual Instrument Systems in Reality (VISIR). VISIR allows wiring and measuring of electronic circuits remotely on a virtual workbench that replicates physical circuit breadboards. The wiring mechanism is developed by means of a relay switching matrix connected to a PCI…

  15. Virtual Instrument Systems in Reality (VISIR) for Remote Wiring and Measurement of Electronic Circuits on Breadboard

    ERIC Educational Resources Information Center

    Tawfik, M.; Sancristobal, E.; Martin, S.; Gil, R.; Diaz, G.; Colmenar, A.; Peire, J.; Castro, M.; Nilsson, K.; Zackrisson, J.; Hakansson, L.; Gustavsson, I.

    2013-01-01

    This paper reports on a state-of-the-art remote laboratory project called Virtual Instrument Systems in Reality (VISIR). VISIR allows wiring and measuring of electronic circuits remotely on a virtual workbench that replicates physical circuit breadboards. The wiring mechanism is developed by means of a relay switching matrix connected to a PCI

  16. Toward a Reduced-Wire Readout System for Ultrasound Imaging

    PubMed Central

    Lim, Jaemyung; Arkan, Evren F.; Degertekin, F. Levent; Ghovanloo, Maysam

    2015-01-01

    We present a system-on-a-chip (SoC) for use in high-frequency capacitive micromachined ultrasonic transducer (CMUT) imaging systems. This SoC consists of trans-impedance amplifiers (TIA), delay locked loop (DLL) based clock multiplier, quadrature sampler, and pulse width modulator (PWM). The SoC down converts RF echo signal to baseband by quadrature sampling which facilitates modulation. To send data through a 1.6 m wire in the catheter which has limited bandwidth and is vulnerable to noise, the SoC creates a pseudo-digital PWM signal which can be used for back telemetry or wireless readout of the RF data. In this implementation, using a 0.35-μm std. CMOS process, the TIA and single-to-differential (STD) converter had 45 MHz bandwidth, the quadrature sampler had 10.1 dB conversion gain, and the PWM had 5-bit ENoB. Preliminary results verified front-end functionality, and the power consumption of a TIA, STD, quadrature sampler, PWM, and clock multiplier was 26 mW from a 3 V supply. PMID:25571135

  17. Toward a reduced-wire readout system for ultrasound imaging.

    PubMed

    Lim, Jaemyung; Arkan, Evren F; Degertekin, F Levent; Ghovanloo, Maysam

    2014-01-01

    We present a system-on-a-chip (SoC) for use in high-frequency capacitive micromachined ultrasonic transducer (CMUT) imaging systems. This SoC consists of trans-impedance amplifiers (TIA), delay locked loop (DLL) based clock multiplier, quadrature sampler, and pulse width modulator (PWM). The SoC down converts RF echo signal to baseband by quadrature sampling which facilitates modulation. To send data through a 1.6 m wire in the catheter which has limited bandwidth and is vulnerable to noise, the SoC creates a pseudo-digital PWM signal which can be used for back telemetry or wireless readout of the RF data. In this implementation, using a 0.35-μm std. CMOS process, the TIA and single-to-differential (STD) converter had 45 MHz bandwidth, the quadrature sampler had 10.1 dB conversion gain, and the PWM had 5-bit ENoB. Preliminary results verified front-end functionality, and the power consumption of a TIA, STD, quadrature sampler, PWM, and clock multiplier was 26 mW from a 3 V supply. PMID:25571135

  18. Low speed phaselock speed control system. [for brushless dc motor

    NASA Technical Reports Server (NTRS)

    Fulcher, R. W.; Sudey, J. (Inventor)

    1975-01-01

    A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

  19. Application of Superconducting Power Cables to DC Electric Railway Systems

    NASA Astrophysics Data System (ADS)

    Ohsaki, Hiroyuki; Lv, Zhen; Sekino, Masaki; Tomita, Masaru

    For novel design and efficient operation of next-generation DC electric railway systems, especially for their substantial energy saving, we have studied the feasibility of applying superconducting power cables to them. In this paper it is assumed that a superconducting power cable is applied to connect substations supplying electric power to trains. An analysis model line was described by an electric circuit, which was analyzed with MATLAB-Simulink. From the calculated voltages and currents of the circuit, the regenerative brake and the energy losses were estimated. In addition, assuming the heat loads of superconducting power cables and the cryogenic efficiency, the energy saving of the total system was evaluated. The results show that the introduction of superconducting power cables could achieve the improved use of regenerative brake, the loss reduction, the decreased number of substations, the reduced maintenance, etc.

  20. A One Chip Hardened Solution for High Speed SpaceWire System Implementations. Session: Components

    NASA Technical Reports Server (NTRS)

    Marshall, Joseph R.; Berger, Richard W.; Rakow, Glenn P.

    2007-01-01

    An Application Specific Integrated Circuit (ASIC) that implements the SpaceWire protocol has been developed in a radiation hardened 0.25 micron CMOS technology. This effort began in March 2003 as a joint development between the NASA Goddard Space Flight Center (GSFC) and BAE Systems. The BAE Systems SpaceWire ASIC is comprised entirely of reusable core elements, many of which are already flight-proven. It incorporates a router with 4 SpaceWire ports and two local ports, dual PC1 bus interfaces, a microcontroller, 32KB of internal memory, and a memory controller for additional external memory use. The SpaceWire cores are also reused in other ASICs under development. The SpaceWire ASIC is planned for use on the Geostationary Operational Environmental Satellites (GOES)-R, the Lunar Reconnaissance Orbiter (LRO) and other missions. Engineering and flight parts have been delivered to programs and users. This paper reviews the SpaceWire protocol and those elements of it that have been built into the current and next SpaceWire reusable cores and features within the core that go beyond the current standard and can be enabled or disabled by the user. The adaptation of SpaceWire to BAE Systems' On Chip Bus (OCB) for compatibility with the other reusable cores will be reviewed and highlighted. Optional configurations within user systems and test boards will be shown. The physical implementation of the design will be described and test results from the hardware will be discussed. Application of this ASIC and other ASICs containing the SpaceWire cores and embedded microcontroller to Plug and Play and reconfigurable implementations will be described. Finally, the BAE Systems roadmap for SpaceWire developments will be updated, including some products already in design as well as longer term plans.

  1. Plasma chemistry in wire chambers

    SciTech Connect

    Wise, J.

    1990-05-01

    The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an {sup 55}Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed.

  2. dc and ac Josephson effect in a superconductor-Luttinger-liquid-superconductor system

    NASA Astrophysics Data System (ADS)

    Fazio, Rosario; Hekking, F. W. J.; Odintsov, A. A.

    1996-03-01

    We calculate both the dc and the ac Josephson current through a one-dimensional system of interacting electrons, connected to two superconductors by tunnel junctions. We treat the (repulsive) Coulomb interaction in the framework of the one-channel, spin-1/2 Luttinger model. The Josephson current is obtained for two geometries of experimental relevance: a quantum wire and a ring. At zero temperature, the critical current is found to decay algebraically with increasing distance d between the junctions. The decay is characterized by an exponent which depends on the strength of the interaction. At finite temperatures T, lower than the superconducting transition temperature Tc, there is a crossover from algebraic to exponential decay of the critical current as a function of d, at a distance of the order of ħvF/kBT. Moreover, the dependence of critical current on temperature shows nonmonotonic behavior. If the Luttinger liquid is confined to a ring of circumference L, coupled capacitively to a gate voltage and threaded by a magnetic flux, the Josephson current shows remarkable parity effects under the variation of these parameters. For some values of the gate voltage and applied flux, the ring acts as a π junction. These features are robust against thermal fluctuations up to temperatures on the order of ħvF/kBL. For the wire geometry, we have also studied the ac-Josephson effect. The amplitude and the phase of the time-dependent Josephson current are affected by electron-electron interactions. Specifically, the amplitude shows pronounced oscillations as a function of the bias voltage due to the difference between the velocities of spin and charge excitations in the Luttinger liquid. Therefore, the ac-Josephson effect can be used as a tool for the observation of spin-charge separation.

  3. Topological variations of the inverse dual converter for high-power dc-dc distribution systems

    NASA Astrophysics Data System (ADS)

    Ehsani, Mehrdad; Laskai, Laszlo

    New dc-to-dc converter topologies are presented which are suitable for high density high power supplies. Topological variations of the basic inverse dual converter (IDC) circuit such as the transformer coupled, the multiphase and the multipulse derivation of the single phase IDC have been analyzed and some simulation results have been presented. The single phase IDC offers a buck-boost operation over wide range without transformer, bidirectional power flow, and complementary commutation of the switches. The topologies examined in this paper have additional features such as lower device and component stresses, and smaller filter requirements, resulting in smaller size and weight. Some performance and possible applications are also examined. IDCs for serial and parallel power distribution, and ac tapping of the IDC are discussed.

  4. Modeling of brushless dc generating systems using diakoptics

    NASA Astrophysics Data System (ADS)

    Vadher, Vinod; Gregory, Keith; Kettleborough, J. G.; Smith, Ivor R.

    1993-01-01

    The mathematical modeling of a brushless dc generator is described, as an illustration of the application of diakoptic techniques to the analysis of small-scale electrical power supply systems. Modeling of the generator and its output rectifier is accomplished using an established matrix technique that accounts for the continuously changing conduction pattern of the diode bridge network. The advantages of using diakoptics are introduced when consideration is given to the main generator linked to its exciter and to the automatic voltage regulator and permanent magnet generator which are often included in a complete unit. A solution algorithm is presented for this overall arrangement and a comparison is made between theoretical and practical results for a typical 3-stage 4000 rev/min 10.3 kW 28 V unit.

  5. Discharging a DC bus capacitor of an electrical converter system

    DOEpatents

    Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

    2014-10-14

    A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

  6. [Automatic adjustment control system for DC glow discharge plasma source].

    PubMed

    Wan, Zhen-zhen; Wang, Yong-qing; Li, Xiao-jia; Wang, Hai-zhou; Shi, Ning

    2011-03-01

    There are three important parameters in the DC glow discharge process, the discharge current, discharge voltage and argon pressure in discharge source. These parameters influence each other during glow discharge process. This paper presents an automatic control system for DC glow discharge plasma source. This system collects and controls discharge voltage automatically by adjusting discharge source pressure while the discharge current is constant in the glow discharge process. The design concept, circuit principle and control program of this automatic control system are described. The accuracy is improved by this automatic control system with the method of reducing the complex operations and manual control errors. This system enhances the control accuracy of glow discharge voltage, and reduces the time to reach discharge voltage stability. The glow discharge voltage stability test results with automatic control system are provided as well, the accuracy with automatic control system is better than 1% FS which is improved from 4% FS by manual control. Time to reach discharge voltage stability has been shortened to within 30 s by automatic control from more than 90 s by manual control. Standard samples like middle-low alloy steel and tin bronze have been tested by this automatic control system. The concentration analysis precision has been significantly improved. The RSDs of all the test result are better than 3.5%. In middle-low alloy steel standard sample, the RSD range of concentration test result of Ti, Co and Mn elements is reduced from 3.0%-4.3% by manual control to 1.7%-2.4% by automatic control, and that for S and Mo is also reduced from 5.2%-5.9% to 3.3%-3.5%. In tin bronze standard sample, the RSD range of Sn, Zn and Al elements is reduced from 2.6%-4.4% to 1.0%-2.4%, and that for Si, Ni and Fe is reduced from 6.6%-13.9% to 2.6%-3.5%. The test data is also shown in this paper. PMID:21595252

  7. Manchester Coding Option for SpaceWire: Providing Choices for System Level Design

    NASA Technical Reports Server (NTRS)

    Rakow, Glenn; Kisin, Alex

    2014-01-01

    This paper proposes an optional coding scheme for SpaceWire in lieu of the current Data Strobe scheme for three reasons. First reason is to provide a straightforward method for electrical isolation of the interface; secondly to provide ability to reduce the mass and bend radius of the SpaceWire cable; and thirdly to provide a means for a common physical layer over which multiple spacecraft onboard data link protocols could operate for a wide range of data rates. The intent is to accomplish these goals without significant change to existing SpaceWire design investments. The ability to optionally use Manchester coding in place of the current Data Strobe coding provides the ability to DC balanced the signal transitions unlike the SpaceWire Data Strobe coding; and therefore the ability to isolate the electrical interface without concern. Additionally, because the Manchester code has the clock and data encoded on the same signal, the number of wires of the existing SpaceWire cable could be optionally reduced by 50. This reduction could be an important consideration for many users of SpaceWire as indicated by the already existing effort underway by the SpaceWire working group to reduce the cable mass and bend radius by elimination of shields. However, reducing the signal count by half would provide even greater gains. It is proposed to restrict the data rate for the optional Manchester coding to a fixed data rate of 10 Megabits per second (Mbps) in order to make the necessary changes simple and still able to run in current radiation tolerant Field Programmable Gate Arrays (FPGAs). Even with this constraint, 10 Mbps will meet many applications where SpaceWire is used. These include command and control applications and many instruments applications with have moderate data rate. For most NASA flight implementations, SpaceWire designs are in rad-tolerant FPGAs, and the desire to preserve the heritage design investment is important for cost and risk considerations. The Manchester coding option can be accommodated in existing designs with only changes to the FPGA.

  8. Study of a piezoelectric transformer-based DC/DC converter with a cooling system and current-doubler rectifier

    NASA Astrophysics Data System (ADS)

    Su, Yu-Hao; Liu, Yuan-Ping; Vasic, Dejan; Costa, Francois; Wu, Wen-Jong; Lee, Chuih-Kung

    2013-09-01

    The objective of this study was to increase the output current and power in a piezoelectric transformer (PT)-based DC/DC converter by using a cooling system. It is known that the output current of a PT is limited by temperature build-up because of losses, especially when driving at high vibration velocity. Although connecting different inductive circuits at the PT secondary terminal can increase the output current, the root cause of the temperature build-up problem has not yet been solved. This paper presents a study of a PT with cooling system in a DC/DC converter with a commonly used full-bridge rectifier and current-doubler rectifier. The advantages and disadvantages of the proposed technique were investigated. A theoretical-phenomenological model was developed to explain the relationship between the losses and the temperature rise. It will be shown that the vibration velocity as well as heat generation increases the losses. In our design, the maximum output current capacity can increase by 100% when the temperature of operation of the PT is kept below 55 ° C. The study comprises a theoretical part and experimental proof-of-concept demonstration of the proposed design method.

  9. 47 CFR 68.213 - Installation of other than “fully protected” non-system simple customer premises wiring.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... non-system simple customer premises wiring. 68.213 Section 68.213 Telecommunication FEDERAL... protected” non-system simple customer premises wiring. (a) Scope of this rule. Provisions of this rule apply... residential and business telephone service. More complex installations of wiring for multiple line...

  10. Beam Emittance Measurement with Laser Wire Scanners in the ILC Beam Delivery System

    SciTech Connect

    Agapov, I.; Blair, G.A.; Woodley, M.; /SLAC

    2008-02-01

    Accurate measurement of the beam phase-space is essential for the next generation of electron accelerators. A scheme for beam optics optimization and beam matrix reconstruction algorithms for the diagnostics section of the beam delivery system of the International Linear Collider based on laser-wire beam profile monitors are discussed. Possible modes of operation of the laser-wire system together with their corresponding performance are presented. Based on these results, prospects for reconstructing the ILC beam emittance from representative laser-wire beam size measurements are evaluated.

  11. Active dc filter for HVDC system--A test installation in the Konti-Skan DC link at Lindome converter station

    SciTech Connect

    Zhang, Wenyan; Asplund, G. . HVDC Division); Aberg, A. . Dept. of Man-Machine Communication); Jonsson, U. ); Loeoef, O. . Region Vaestsverige)

    1993-07-01

    The purpose of introducing active dc filters is to meet the more and more stringent requirement from power utilities on limiting telephone interference caused by harmonic currents from HVdc transmission lines, without unnecessarily increasing the cost of HVdc stations. An active dc filter installed in the Konti-Skan HVdc link is described. The active dc filter is connected at the bottom of an existing passive dc filter at the Lindome station. The active dc filter includes optic harmonic current measuring unit, control system, protection and supervision system, PWM power amplifier, high-frequency transformer, surge arrester, and coupling apparatuses. The active dc filter has small physical size and occupies small ground area. The performance of the active dc filter for eliminating the disturbing harmonics is excellent. To achieve comparable results by passive filters would require something like ten times more high voltage equipment.

  12. Research on the dynamic detection system for detecting the height of contact wire

    NASA Astrophysics Data System (ADS)

    Wang, Li; Li, Jinlong; Gao, Xiaorong; Wang, Zeyong; Zhao, Quanke

    2007-12-01

    The height of contact wire is one of the important technical parameter of OCS (Overhead Contact System) in electric railway. The device introduced in this paper is installed on the operating electric locomotives, and the height of the contact wire can be detected in real-time. In this paper, the system structure, working principle, installation and mechanical design are all introduced in detail. The precision is analyzed; the applied situation and the detecting results are given as well.

  13. Research study on multi-KW-DC distribution system

    NASA Technical Reports Server (NTRS)

    Berkery, E. A.; Krausz, A.

    1975-01-01

    A detailed definition of the HVDC test facility and the equipment required to implement the test program are provided. The basic elements of the test facility are illustrated, and consist of: the power source, conventional and digital supervision and control equipment, power distribution harness and simulated loads. The regulated dc power supplies provide steady-state power up to 36 KW at 120 VDC. Power for simulated line faults will be obtained from two banks of 90 ampere-hour lead-acid batteries. The relative merits of conventional and multiplexed power control will be demonstrated by the Supervision and Monitor Unit (SMU) and the Automatically Controlled Electrical Systems (ACES) hardware. The distribution harness is supported by a metal duct which is bonded to all component structures and functions as the system ground plane. The load banks contain passive resistance and reactance loads, solid state power controllers and active pulse width modulated loads. The HVDC test facility is designed to simulate a power distribution system for large aerospace vehicles.

  14. A Theory of Control for a Class of Electronic Power Processing Systems: Energy-Storage DC-To-DC Converters. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Burns, W. W., III

    1977-01-01

    An analytically derived approach to the control of energy-storage dc-to-dc converters, which enables improved system performance and an extensive understanding of the manner in which this improved performance is accomplished, is presented. The control approach is derived from a state-plane analysis of dc-to-dc converter power stages which enables a graphical visualization of the movement of the system state during both steady state and transient operation. This graphical representation of the behavior of dc-to-dc converter systems yields considerable qualitative insight into the cause and effect relationships which exist between various commonly used converter control functions and the system performance which results from them.

  15. NASA requirements and applications environments for electrical power wiring

    NASA Technical Reports Server (NTRS)

    Stavnes, Mark W.; Hammond, Ahmad N.

    1992-01-01

    While a large data base for electrical arc track-resistant wire insulation exists for aircraft electrical power systems, comparable spacecraft-pertinent data are in limited supply. Existing insulation systems have been found to arc-track at potentials as low as 28 V dc. An account is presently given of the electrical, thermal, mechanical, and operational requirements for specification and testing of candidate wiring systems for spacecraft applications.

  16. Transient analysis of an HTS DC power cable with an HVDC system

    NASA Astrophysics Data System (ADS)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun; Yang, Byeongmo

    2013-11-01

    The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.

  17. 78 FR 1 - Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for Printing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-02

    ... Register on December 14, 2012 (77 FR 74347), the U.S. Office of Personnel Management (OPM) incorrectly... 3206-AM59 Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for..., 2012, abolishing the Washington, DC, Federal Wage System special wage schedule for printing...

  18. Novel DC ring topology and protection system - a comprehensive solution for mega city power grids

    NASA Astrophysics Data System (ADS)

    Haj-Maharsi, Mohamed Yassine

    2009-07-01

    The development of mega cities leads to increased load concentration and brings additional challenges to managing the electrical grid while keeping power available for critical loads. Techniques using FACTS devices are being applied to alleviate power management difficulties and to confine faults in their originating areas in order to limit the risk of cascading failures in the grid. The addition of many FACTS devices often results in control and protection coordination difficulties, power oscillations between connected networks, subsynchronous resonance problems, and torsional interactions with nearby generator units. The most effective solution is obtained when the individual AC subsystems representing sources and loads are decoupled so a fault in a given subsystem is not propagated to another subsystem. This solution can be achieved by the deployment of a DC system where power sources and loads are connected to the DC bus through voltage source converters. For a mega city, this would be conceived as a DC ring feeding multiple loads and connected to remote and local power sources. Unfortunately, the lack of fast DC circuit breakers has been one of the key issues affecting extensive applications of DC systems with common DC buses; a DC fault would discharge all the capacitors of the DC bus and cause delays in system recovery and possibly a wide system collapse. In this research, I provide a comprehensive solution to mega city power grid problems by proposing a DC system topology that enables grid expansions without affecting existing protection settings or changing existing AC breaker ratings. I also propose the means for protecting the DC system by designing a fast DC breaker and developing a control algorithm capable of isolating DC faults without blocking converter stations or depleting DC bus capacitors. My contribution is three folds: (1) I modeled and simulated Shanghai power grid and performed a study to identify short circuit and voltage stability problems using data provided by ABB corporate research located in China. I built on the work that had been performed in ABB China by considering different contingencies and I applied solutions using individual FACTS devices such as FCL, SVC-LightRTM, and HVDC-LightRTM. I analyzed the results from each solution in order to assess its merits and limitations in dealing with fault current and voltage stability problems. Then I presented a novel DC ring topology that provides redundancy, better protection against cascading faults, and does not increase short circuit levels. With this topology, adding loads or power sources does not impact system protection or performance. (2) I proposed two novel designs for a DC circuit breaker that is of critical importance to DC applications using multiple converter stations. The proposed designs solve the problem of DC fault clearing without causing significant voltage drops, current oscillations, or shutting down of any converter station connected to the DC bus. The DC breaker rated at a voltage of 320 kV and a current of 3000 A can interrupt DC currents as high as 70 kA within 800 mus. (3) I proposed a novel placement of the DC circuit breakers within the DC ring topology combined with an intelligent protection algorithm that optimizes fault detection and isolation without affecting the rest of the DC system. The protection scheme uses local measurements and special coordination techniques for clearing solid faults and uses differential measurements to identify and isolate high impedance faults.

  19. The DC-SQUID-based Magnetocardiographic Systems for Clinical Use

    NASA Astrophysics Data System (ADS)

    Maslennikov, Yu. V.; Primin, M. A.; Slobodchikov, V. Yu.; Khanin, V. V.; Nedayvoda, I. V.; Krymov, V. A.; Okunev, A. V.; Moiseenko, E. A.; Beljaev, A. V.; Rybkin, V. S.; Tolcheev, A. V.; Gapelyuk, A. V.

    The new line of dc-SQUID-based magnetocardiographic (MCG) systems (named as the "MAG-SCAN"-family) is designed, fabricated and tested. These systems are intended for routine MCG investigations of patients at conditions of real clinical electrophysiological labs. The "MAG-SCAN"-family includes the line of MCG devices compatible in terms of hardware and software with number of measuring channels from 1 to 36. Experimental prototypes of 7- and 9-channel MCG-systems (the models "MAG-SCAN-07" and "MAG-SCAN-09" fabricated at CRYOTON Co. Ltd.) were installed in a few hospitals of Moscow city and operated in an unshielded environment of usual clinical labs. Well balanced second-order gradiometers have been used for MCG data recording. They demonstrated an intrinsic noise level better than 5 fT/√Hz. The total noise level of about 20-40 fT/√Hz was measured at urban conditions of Moscow city. The package of special software (named as the "SOFTMAG") was developed as two autonomous subsystems that allow the preprocessing of the heart magnetic signals and the spatio-temporal analysis of the field characteristics and the field sources. The software employs the algorithms for the analysis and estimation of the spatio-temporal characteristics of the heart magnetic field and the correspondent electrical currents distributions. More than 2000 investigations of different volunteers including healthy persons, patients with high blood-pressure, ischemic disease (IHD), chronic obstructive pulmonary disease (COPD) and bronchial asthma (BA) were carried out and sets of MCG-parameters specific for each group were found.

  20. Advanced medium-voltage bidirectional dc-dc conversion systems for future electric energy delivery and management systems

    NASA Astrophysics Data System (ADS)

    Fan, Haifeng

    2011-12-01

    The distributed renewable energy generation and utilization are constantly growing, and are expected to be integrated with the conventional grid. The growing pressure for innovative solutions will demand power electronics to take an even larger role in future electric energy delivery and management systems, since power electronics are required for the conversion and control of electric energy by most dispersed generation systems Furthermore, power electronics systems can provide additional intelligent energy management, grid stability and power quality capabilities. Medium-voltage isolated dc-dc converter will become one of the key interfaces for grid components with moderate power ratings. To address the demand of medium voltage (MV) and high power capability for future electric energy delivery and management systems, the power electronics community and industry have been reacting in two different ways: developing semiconductor technology or directly connecting devices in series/parallel to reach higher nominal voltages and currents while maintaining conventional converter topologies; and by developing new converter topologies with traditional semiconductor technology, known as multilevel converters or modular converters. The modular approach uses the well-known, mature, and cheaper power semiconductor devices by adopting new converter topologies. The main advantages of the modular approach include: significant improvement in reliability by introducing desired level of redundancy; standardization of components leading to reduction in manufacturing cost and time; power systems can be easily reconfigured to support varying input-output specifications; and possibly higher efficiency and power density of the overall system. Input-series output-parallel (ISOP) modular configuration is a good choice to realize MV to low voltage (LV) conversion for utility application. However, challenges still remain. First of all, for the high-frequency MV utility application, the low switching loss and conduction loss are must-haves for high efficiency, while bidirectional power flow capability is a must for power management requirement. To address the demand, the phase-shift dual-halfbridge (DHB) is proposed as the constituent module of ISOP configuration for MV application. The proposed ISOP DHB converter employs zero-voltage-switching (ZVS) technique combined with LV MOSFETs to achieve low switching and conduction losses under high frequency operation, and therefore high efficiency and high power density, and bidirectional power flow as well. Secondly, a large load range of high efficiency is desired rather than only a specific load point due to the continuous operation and large load variation range of utility application, which is of high importance because of the rising energy cost. This work proposes a novel DHB converter with an adaptive commutation inductor. By utilizing an adaptive inductor as the main energy transfer element, the output power can be controlled by not only the phase shift but also the commutation inductance, which allows the circulating energy to be optimized for different load conditions to maintain ZVS under light load conditions and minimize additional conduction losses under heavy load conditions as well. As a result, the efficiency at both light and heavy load can be significantly improved compared with the conventional DHB converter, and therefore extended high-efficiency range can be achieved. In addition, current stress of switch devices can be reduced. The theoretical analysis is presented and validated by the experimental results on a 50 kHz, 1 kW dc-dc converter module. Thirdly, input-voltage sharing and output-current sharing are critical to assure the advantages of the ISOP modular configuration. To solve this issue, an identically distributed control scheme is proposed in this work. The proposed control scheme, using only one distributed voltage loop to realize both input-voltage and output-current sharing, provides plug-and-play capability, possible high-level fault tolerance, and easy implementation. Another unique advantage of the proposed ISOP DHB converter is the power rating can be easily extended further by directly connecting multiple ISOP DHB converters in input-parallel-outparallel (IPOP) while no additional control is needed. The proposed control scheme is elaborated using the large-signal average model. Further, the stability of the control schemes is analyzed in terms of the constituent modules' topology as well as the configuration, and then an important fact that the stability of control scheme depends on not only the configuration but also the constituent module topology is first revealed in this work. Finally, the simulation and experimental results of an ISOP DHB converter consisting of three modules are presented to verify the proposed control scheme and the high frequency high efficiency operation.

  1. Discharge Characteristic of VHF-DC Superimposed Magnetron Sputtering System

    NASA Astrophysics Data System (ADS)

    Toyoda, Hirotaka; Fukuoka, Yushi; Fukui, Takashi; Takada, Noriharu; Sasai, Kensuke

    2014-10-01

    Magnetron plasmas are one of the most important tools for sputter deposition of thin films. However, energetic particles from the sputtered target such as backscattered rare gas atoms or oxygen negative ions from oxide targets sometimes induce physical and chemical damages as well as surface roughening to the deposited film surface during the sputtering processes. To suppress kinetic energy of such particles, superposition of RF or VHF power to the DC power has been investigated. In this study, influence of the VHF power superposition on the DC target voltage, which is important factor to determine kinetic energy of high energy particles, is investigated. In the study, 40 MHz VHF power was superimposed to an ITO target and decrease in the target DC voltage was measured as well as deposited film deposition properties such as deposition rate or electrical conductivity. From systematic measurement of the target voltage, it was revealed that the target voltage can be determined by a very simple parameter, i.e., a ratio of VHF power to the total input power (DC and VHF powers) in spite of the DC discharge current. Part of this work was supported by ASTEP, JST.

  2. Adaptable DC offset correction

    NASA Technical Reports Server (NTRS)

    Golusky, John M. (Inventor); Muldoon, Kelly P. (Inventor)

    2009-01-01

    Methods and systems for adaptable DC offset correction are provided. An exemplary adaptable DC offset correction system evaluates an incoming baseband signal to determine an appropriate DC offset removal scheme; removes a DC offset from the incoming baseband signal based on the appropriate DC offset scheme in response to the evaluated incoming baseband signal; and outputs a reduced DC baseband signal in response to the DC offset removed from the incoming baseband signal.

  3. Nonlinear modal interaction in HVDC/AC power systems with dc power modulation

    SciTech Connect

    Ni, Y.X.; Vittal, V.; Kliemann, W.; Fouad, A.A.

    1996-11-01

    In this paper investigation of nonlinear modal interaction using the normal form of vector fields technique is extended to HVDC/AC power systems with dc power modulation. The ac-dc interface equations are solved to form a state space model with second order approximation. Using the normal form technique, the system`s nonlinear dynamic characteristics are obtained. The proposed approach is applied to a 4-generator HVDC/AC test power system, and compare with the time domain solution.

  4. An optimal control strategy for DC bus voltage regulation in photovoltaic system with battery energy storage.

    PubMed

    Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A

    2014-01-01

    This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

  5. An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

    PubMed Central

    Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M. A.

    2014-01-01

    This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

  6. Turbulence Measurements by the DC-8 Meteorological Measurement System

    NASA Technical Reports Server (NTRS)

    Chan, K. R.; Dean-Day, J.; Bowen, S. W.; Bui, T. P.; Chan, K. Roland (Technical Monitor)

    1997-01-01

    The instrumentation of a new MMS on the DC-8 aircraft is briefly described. Methods to compute and evaluate the turbulent dissipation rate epsilon, based on theory and MMS data, are discussed. Examples of turbulence measurements during encounters of a wake vortex, wave clouds, persistent contrails, mountain are gravity waves are illustrated.

  7. DC drive system for cine/pulse cameras

    NASA Technical Reports Server (NTRS)

    Gerlach, R. H.; Sharpsteen, J. T.; Solheim, C. D.; Stoap, L. J.

    1977-01-01

    Camera-drive functions are separated mechanically into two groups which are driven by two separate dc brushless motors. First motor, a 90 deg stepper, drives rotating shutter; second electronically commutated motor drives claw and film transport. Shutter is made of one piece but has two openings for slow and fast exposures.

  8. Strata reinforcement with bolting and wire-rope systems - a comparative study

    SciTech Connect

    Raju, N.M.; Ghose, A.K.

    1982-04-01

    A strata reinforcement system which has been used on an experimental basis in some 60 Indian coal mines over the past 6 years is described. It consists of a system of 'rope stitching' in which wire rope is stretched across the roof of the roadway and the ends are grouted into 1.8 m drill holes. For spans exceedng 3.6 m, grouted bolts with eye hooks are used for additional reinforcement at mid-span. This paper presents the results of a model study to evaluate the relative reinforcement actions of wire-rope and bolting systems.

  9. Innate immune system favors emergency monopoiesis at the expense of DC-differentiation to control systemic bacterial infection in mice.

    PubMed

    Pasquevich, Karina A; Bieber, Kristin; Günter, Manina; Grauer, Matthias; Pötz, Oliver; Schleicher, Ulrike; Biedermann, Tilo; Beer-Hammer, Sandra; Bühring, Hans-Jörg; Rammensee, Hans-Georg; Zender, Lars; Autenrieth, Ingo B; Lengerke, Claudia; Autenrieth, Stella E

    2015-10-01

    DCs are professional APCs playing a crucial role in the initiation of T-cell responses to combat infection. However, systemic bacterial infection with various pathogens leads to DC-depletion in humans and mice. The mechanisms of pathogen-induced DC-depletion remain poorly understood. Previously, we showed that mice infected with Yersinia enterocolitica (Ye) had impaired de novo DC-development, one reason for DC-depletion. Here, we extend these studies to gain insight into the molecular mechanisms of DC-depletion and the impact of different bacteria on DC-development. We show that the number of bone marrow (BM) hematopoietic progenitors committed to the DC lineage is reduced following systemic infection with different Gram-positive and Gram-negative bacteria. This is associated with a TLR4- and IFN-γ-signaling dependent increase of committed monocyte progenitors in the BM and mature monocytes in the spleen upon Ye-infection. Adoptive transfer experiments revealed that infection-induced monopoiesis occurs at the expense of DC-development. Our data provide evidence for a general response of hematopoietic progenitors upon systemic bacterial infections to enhance monocyte production, thereby increasing the availability of innate immune cells for pathogen control, whereas impaired DC-development leads to DC-depletion, possibly driving transient immunosuppression in bacterial sepsis. PMID:26138432

  10. Biological wires, communication systems, and implications for disease.

    PubMed

    Friesen, Douglas E; Craddock, Travis J A; Kalra, Aarat P; Tuszynski, Jack A

    2015-01-01

    Microtubules, actin, and collagen are macromolecular structures that compose a large percentage of the proteins in the human body, helping form and maintain both intracellular and extracellular structure. They are biological wires and are structurally connected through various other proteins. Microtubules (MTs) have been theorized to be involved in classical and quantum information processing, and evidence continues to suggest possible semiconduction through MTs. The previous Dendritic Cytoskeleton Information Processing Model has hypothesized how MTs and actin form a communication network in neurons. Here, we review information transfer possibilities involving MTs, actin, and collagen, and the evidence of an organism-wide high-speed communication network that may regulate morphogenesis and cellular proliferation. The direct and indirect evidence in support of this hypothesis, and implications for chronic diseases such as cancer and neurodegenerative diseases are discussed. PMID:25448891

  11. Combined Operation of AC and DC Distribution System with Distributed Generation Units

    NASA Astrophysics Data System (ADS)

    Noroozian, Reza; Abedi, Mehrdad; Gharehpetian, Gevorg

    2010-07-01

    This paper presents a DC distribution system which has been supplied by external AC systems as well as local DG units in order to demonstrate an overall solution to power quality issue. In this paper, the proposed operation method is demonstrated by simulation of power transfer between external AC systems, DG units, AC and DC loads. The power flow control in DC distribution system has been achieved by network converters and DG converters. Also, the mathematical model of the network, DG and load converters are obtained by using the average technique, which allows converter systems accurately simulated and control strategies for this converters is achieved. A suitable control strategy for network converters has been proposed that involves DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control technique has been proposed for DG converters. In this paper, a novel control system based on stationary and synchronously rotating reference frame has been proposed for load converters for supplying AC loads connected to the DC bus by balanced voltages. The several case studies have been studied based on proposed methods. The simulation results show that DC distribution systems including DG units can improve the power quality at the point of common coupling (PCC) in the power distribution system or industrial power system.

  12. Characteristics of a large system of pad readout wire proportional chambers for the HPC calorimeter

    SciTech Connect

    Camporesi, T.; Cavallo, F.R.; Giordano, V.; Laurenti, G.; Molinari, G.; Navarria, F.L.; Privitera, P.; Rovelli, T.; Valenti, G.; Zucchini, A.

    1989-02-01

    A large system of wire proportional chambers is being constructed for the readout of the High-Density Projection Chamber (HPC) of the DELPHI experiment at the Large Electron-Positron storage ring. The system consists of 144 chambers, each 0.3 m/sup 2/ wide and read out via cathode pads, located at the end of the HPC drift volume.

  13. Three-dimensional wire-mesh capacitor system measures fluid density

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Gaging system automatically measures the bulk density of a stored, electrically nonconductive fluid containing varying portions of liquid and vapor. The system employs a three-dimensional wire-mesh capacitor whose capacitance varies with the bulk density of the fluid dielectric medium between the capacitor plates.

  14. High dynamic range diamond detector acquisition system for beam wire scanner applications

    NASA Astrophysics Data System (ADS)

    Sirvent, J. L.; Dehning, B.; Piselli, E.; Emery, J.; Dieguez, A.

    2016-03-01

    The CERN Beam Instrumentation group has been working during the last years on the beam wire scanners upgrade to cope up with the increasing requirements of CERN experiments. These devices are used to measure the beam profile by crossing a thin wire through a circulating beam, the resulting secondary particles produced from beam/wire interaction are detected and correlated with the wire position to reconstruct the beam profile. The upgraded secondary particles acquisition electronics will use polycrystalline chemical vapour deposition (pCVD) diamond detectors for particle shower measurements, with low noise acquisitions performed on the tunnel, near the detector. The digital data is transmitted to the surface through an optical link with the GBT protocol. Two integrator ASICs (ICECAL and QIE10) are being characterized and compared for detector readout with the complete acquisition chain prototype. This contribution presents the project status, the QIE10 front-end performance and the first measurements with the complete acquisition system prototype. In addition, diamond detector signals from particle showers generated by an operational beam wire scanner are analysed and compared with an operational system.

  15. Very low noise AC/DC power supply systems for large detector arrays.

    PubMed

    Arnaboldi, C; Baù, A; Carniti, P; Cassina, L; Giachero, A; Gotti, C; Maino, M; Passerini, A; Pessina, G

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μV(RMS) (CUORE setup) and 90 μV(RMS) (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled). PMID:26724052

  16. Very low noise AC/DC power supply systems for large detector arrays

    NASA Astrophysics Data System (ADS)

    Arnaboldi, C.; Baù, A.; Carniti, P.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Passerini, A.; Pessina, G.

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μVRMS (CUORE setup) and 90 μVRMS (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled).

  17. Development of a uninterrupted power system: ac and dc to dc converter

    NASA Technical Reports Server (NTRS)

    Cronin, D. L.; Schoenfeld, A. D.

    1973-01-01

    This program covered the design, fabrication and testing of an advanced development model uninterrupted power system. The input and output requirements imposed on the power processor were specified such that the unit is electrically interchangeable with existing power systems used by the Federal Aviation Administration in installations which have a history of failure due to electrical transient conditions. Input power is from either of two single-phase ac power sources or batteries with electronic selection and transfer between power sources. Battery reconditioning is automatic when either ac source is present. The output power is rated at 84OW; the nominal output is 24V at 35A. Within the 84OW limit, the regulated output voltage is adjustable from 22V to 30Vdc. Protection against continuous overloading or short circuit is provided. The unit is packaged in a standard 19-inch rack mount configuration with 7-inch panel height. Controls are on the front panel with power input and output through connectors on the rear surface. Cooling is by free convection from fin areas located on the side and rear panels. The packaged unit weighs 52.8 lbs., which can be reduced significantly if a three-phase ac power source is used.

  18. Secondary particle acquisition system for the CERN beam wire scanners upgrade

    NASA Astrophysics Data System (ADS)

    Sirvent, J. L.; Dehning, B.; Emery, J.; Diéguez, A.

    2015-04-01

    The increasing requirements of CERN experiments make essential the upgrade of beam instrumentation in general, and high accuracy beam profile monitors in particular. The CERN Beam Instrumentation Group has been working during the last years on the Wire Scanners upgrade. These systems cross a thin wire through a circulating beam, the resulting secondary particles produced from beam/wire interaction are detected to reconstruct the beam profile. For the new secondary shower acquisition system, it is necessary to perform very low noise measurements with high dynamic range coverage. The aim is to design a system without tuneable parameters and compatible for any beam wire scanner location at the CERN complex. Polycrystalline chemical vapour deposition diamond detectors (pCVD) are proposed as new detectors for this application because of their radiation hardness, fast response and linearity over a high dynamic range. For the detector readout, the acquisition electronics must be designed to exploit the detector capabilities and perform bunch by bunch measurements at 40MHz. This paper describes the design challenges of such a system, analysing different acquisition possibilities from the signal integrity point of view. The proposed system architecture is shown in detail and the development status presented.

  19. Differences in the force system delivered by different beta-titanium wires in elaborate designs

    PubMed Central

    Martins, Renato Parsekian; Caldas, Sergei Godeiro Fernandes Rabelo; Ribeiro, Alexandre Antonio; Vaz, Luís Geraldo; Shimizu, Roberto Hideo; Martins, Lídia Parsekian

    2015-01-01

    Abstract Objective: Evaluation of the force system produced by four brands of b-Ti wires bent into an elaborate design. Methods: A total of 40 T-loop springs (TLS) hand-bent from 0.017 x 0.025-in b-Ti were randomly divided into four groups according to wire brand: TMATM(G1), BETA FLEXYTM (G2), BETA III WIRETM (G3) and BETA CNATM (G4). Forces and moments were recorded by a moment transducer, coupled to a digital extensometer indicator adapted to a testing machine, every 0.5 mm of deactivation from 5 mm of the initial activation. The moment-to-force (MF) ratio, the overlapping of the vertical extensions of the TLSs and the load-deflection (LD) ratio were also calculated. To complement the results, the Young's module (YM) of each wire was determined by the slope of the load-deflection graph of a tensile test. The surface chemical composition was also evaluated by an energy dispersive X-ray fluorescence spectrometer. Results: All groups, except for G2, produced similar force levels initially. G3 produced the highest LD rates and G1 and G4 had similar amounts of overlap of the vertical extensions of the TLSs in "neutral position". G1 and G3 delivered the highest levels of moments, and G2 and G3 produced the highest MF ratios. b-Ti wires from G3 produced the highest YM and all groups showed similar composition, except for G2. Conclusion: The four beta-titanium wires analyzed produced different force systems when used in a more elaborate design due to the fact that each wire responds differently to bends. PMID:26691975

  20. Testing of a flat conductor cable baseboard system for residential and commercial wiring

    NASA Technical Reports Server (NTRS)

    Hankins, J. D.

    1974-01-01

    The results of extensive testing (mechanical, electrical, chemical, environmental, thermal, and analytical) are reported for a flat conductor cable baseboard system for residential and commercial wiring. In all of the tests, Underwriters Laboratories (UL) Standards, UL Tentative Test Programs, or Accepted Engineering Practices were followed during test selection, test setup, and test accomplishment.

  1. Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization

    SciTech Connect

    Not Available

    2010-11-29

    Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

  2. Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization

    SciTech Connect

    Levashov, Michael Y.

    2010-12-01

    Quadrupoles will be placed between the undulator segments in LCLS to keep the electron beam focused as it passes through. The quadrupoles will be assembled with their respective undulator segments prior to being placed into the tunnel. Beam alignment will be used to center the quadrupoles, along with the corresponding undulators, on the beam. If there is any displacement between the undulator and the quadrupole axes in the assemblies, the beam will deviate from the undulator axis. If it deviates by more than 80{micro}m in vertical or 140{micro}m in horizontal directions, the undulator will not perform as required by LCLS. This error is divided between three sources: undulator axis fiducialization, quadrupole magnetic axis fiducialization, and assembly of the two parts. In particular, it was calculated that the quadrupole needs to be fiducialized to within 25{micro}m in both vertical and horizontal directions. A previous study suggested using a vibrating wire system for finding the magnetic axis of a quadrupole. The study showed that the method has high sensitivity (up to 1{micro}m) and laid out guidelines for constructing it. There are 3 steps in fiducializing the quadrupole with the vibrating wire system. They are positioning the wire at the magnet center (step 1), finding the wire with position detectors (step 2), and finding the quadrupole tooling ball positions relative to the position detector tooling balls (step 3). The following break up of error was suggested for the fiducialization steps: 10{micro}m for step 1 (finding the center), 20{micro}m for step 2 (finding the wire), and 10{micro}m for step 3 (tooling ball measurements). The purpose of this study is to investigate whether the vibrating wire system meets the requirements for LCLS. In particular, if it can reliably fiducialize a quadrupole magnetic center to within 25{micro}m in both vertical and horizontal directions. The behavior of individual system components is compared to the expected performance. A vibrating wire system was constructed to fiducialize the quadrupoles between undulator segments in the LCLS. This note studies the ability of the system to fulfill the fiducialization requirements.

  3. System and Method for Determining Rate of Rotation Using Brushless DC Motor

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2000-01-01

    A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is squared. The squared outputs associated with each winding are combined, with the square root being taken of such combination, to produce a DC output proportional only to the rate of rotation of the motor's shaft.

  4. A laser structured light system for inspection of wear and defects of contact wire in train's electro-supply network

    NASA Astrophysics Data System (ADS)

    Bazin, Vladimir; Chugui, Yuri; Kalichkin, Stepan; Makarov, Sergei; Verkhogliad, Alexander; Vykhristyuk, Ignat

    2006-11-01

    An optical structured illumination of 3D object as a light band method of wear measurement and defects detection of a contact wire network on railways, tram, trolleybus lines and similar systems of vehicles electro-supply is presented. The experimental device can extract main technological wire parameters, as its remaining height with rms value down to 0.1 mm. Also the cross-sectional area of the wire can be measured with rms area noise value of 1.5mm2, which is sufficient for confident decision-making related to the automatic wire wears and defects.

  5. Operation and force analysis of the guide wire in a minimally invasive vascular interventional surgery robot system

    NASA Astrophysics Data System (ADS)

    Yang, Xue; Wang, Hongbo; Sun, Li; Yu, Hongnian

    2015-03-01

    To develop a robot system for minimally invasive surgery is significant, however the existing minimally invasive surgery robots are not applicable in practical operations, due to their limited functioning and weaker perception. A novel wire feeder is proposed for minimally invasive vascular interventional surgery. It is used for assisting surgeons in delivering a guide wire, balloon and stenting into a specific lesion location. By contrasting those existing wire feeders, the motion methods for delivering and rotating the guide wire in blood vessel are described, and their mechanical realization is presented. A new resistant force detecting method is given in details. The change of the resistance force can help the operator feel the block or embolism existing in front of the guide wire. The driving torque for rotating the guide wire is developed at different positions. Using the CT reconstruction image and extracted vessel paths, the path equation of the blood vessel is obtained. Combining the shapes of the guide wire outside the blood vessel, the whole bending equation of the guide wire is obtained. That is a risk criterion in the delivering process. This process can make operations safer and man-machine interaction more reliable. A novel surgery robot for feeding guide wire is designed, and a risk criterion for the system is given.

  6. Department of Energy`s Wire Development Workshop - Superconductivity program for electric systems

    SciTech Connect

    1996-06-01

    The 1996 High-Temperature Superconducting Wire Development Workshop was held on January 31--February 1 at the Crown Plaza Tampa Westshore in Tampa, Florida. The meeting was hosted by Tampa Electric Company and sponsored by the Department of Energy`s Superconductivity Program for Electric Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. Tampa Electric`s Greg Ramon began the meeting by giving a perspective on the changes now occurring in the utility sector. Major program wire development accomplishments during the past year were then highlighted, particularly the world record achievements at Los Alamos and Oak Ridge National Laboratories. The meeting then focussed on three priority technical issues: thallium conductors; AC losses in HTS conductors; and coated conductors on textured substrates. Following in-depth presentations, working groups were formed in each technology area to discuss and critique the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

  7. 77 FR 58424 - Drucker, Inc., DynaMotive Energy Systems Corp., and Gate to Wire Solutions, Inc., Order of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-20

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Drucker, Inc., DynaMotive Energy Systems Corp., and Gate to Wire Solutions, Inc., Order of... current and accurate information concerning the securities of Gate to Wire Solutions, Inc. because it...

  8. Cryogenic Cooling System for 5 kA, 200 μH Class HTS DC Reactor

    NASA Astrophysics Data System (ADS)

    Park, Heecheol; Kim, Seokho; Kim, Kwangmin; Park, Minwon; Park, Taejun; Kim, A.-rong; Lee, Sangjin

    DC reactors, made by aluminum busbar, are used to stabilize the arc of an electric furnace. In the conventional arc furnace, the transport current is several tens of kilo-amperes and enormous resistive loss is generated. To reduce the resistive loss at the DC reactor, a HTS DC reactor can be considered. It can dramatically improve the electric efficiency as well as reduce the installation space. Similar with other superconducting devices, the HTS DC reactor requires current leads from a power source in room temperature to the HTS coil in cryogenic environment. The heat loss at the metal current leads can be minimized through optimization process considering the geometry and the transport current. However, the transport current of the HTS DC reactor for the arc furnace is much larger than most of HTS magnets and the enormous heat penetration through the current lead should be effectively removed to keep the temperature around 70∼77 K. Current leads are cooled down by circulation of liquid nitrogen from the cooling system with a stirling cryocooler. The operating temperature of HTS coil is 30∼40 K and circulation of gaseous helium is used to remove the heat generation at the HTS coil. Gaseous helium is transported through the cryogenic helium blower and a single stage GM cryocooler. This paper describes design and experimental results on the cooling system for current leads and the HTS coil of 5 kA, 200 μH class DC reactor as a prototype. The results are used to verify the design values of the cooling systems and it will be applied to the design of scale-up cooling system for 50 kA, 200 μH class DC reactor.

  9. Reliability of hybrid photovoltaic DC micro-grid systems for emergency shelters and other applications

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.; Schleith, Susan

    2014-10-01

    Improvement of energy efficiency in the SunSmart Schools Emergency Shelters requires new methods for optimizing the energy consumption within the shelters. One major limitation in current systems is the requirement of converting direct current (DC) power generated from the PV array into alternating current (AC) power which is distributed throughout the shelters. Oftentimes, this AC power is then converted back to DC to run certain appliances throughout the shelters resulting in a significant waste of energy due to DC to AC and then again AC to DC conversion. This paper seeks to extract the maximum value out of PV systems by directly powering essential load components within the shelters that already run on DC power without the use of an inverter and above all to make the system reliable and durable. Furthermore, additional DC applications such as LED lighting, televisions, computers and fans operated with DC brushless motors will be installed as replacements to traditional devices in order to improve efficiency and reduce energy consumption. Cost of energy storage technologies continue to decline as new technologies scale up and new incentives are put in place. This will provide a cost effective way to stabilize the energy generation of a PV system as well as to provide continuous energy during night hours. It is planned to develop a pilot program of an integrated system that can provide uninterrupted DC power to essential base load appliances (heating, cooling, lighting, etc.) at the Florida Solar Energy Center (FSEC) command center for disaster management. PV arrays are proposed to be installed on energy efficient test houses at FSEC as well as at private homes having PV arrays where the owners volunteer to participate in the program. It is also planned to monitor the performance of the PV arrays and functioning of the appliances with the aim to improve their reliability and durability. After a successful demonstration of the hybrid DC microgrid based emergency shelter together with the monitoring system, it is planned to replicate it at other schools in Florida and elsewhere to provide continuous power for essential applications, maximizing the value of PV generation systems.

  10. Meissner effect in a system of coupled one-dimensional superconducting wires: Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Qiu, Chunyin; Qian, Tiezheng; Sheng, Ping

    2007-01-01

    Motivated by the observation of superconducting behavior in 4 carbon nanotube-zeolite composites, we use Monte Carlo simulations to evaluate the Meissner effect in a system of coupled one-dimensional superconducting wires. We model the system by using an anisotropic Ginzburg-Landau free energy functional, with distinct transverse and longitudinal coupling constants. By varying the degree of anisotropy, we obtain behaviors ranging from independent wires with suppressed superconducting transition, to an isotropic superconducting system. We numerically evaluate the Meissner effect for finite-sized superconducting domains. Comparison with the experimental data for carbon nanotube-zeolite composite shows the size of the phase-coherent, superconducting domains to be small, i.e., on the order of one or a few transverse coherence lengths. We provide a consistent estimate of the material parameters for the nanotube-zeolite composite, ranging from the penetration length of transverse magnetic field to the longitudinal and transverse coherence lengths.

  11. Detection of High-impedance Arcing Faults in Radial Distribution DC Systems

    NASA Technical Reports Server (NTRS)

    Gonzalez, Marcelo C.; Button, Robert M.

    2003-01-01

    High voltage, low current arcing faults in DC power systems have been researched at the NASA Glenn Research Center in order to develop a method for detecting these 'hidden faults', in-situ, before damage to cables and components from localized heating can occur. A simple arc generator was built and high-speed and low-speed monitoring of the voltage and current waveforms, respectively, has shown that these high impedance faults produce a significant increase in high frequency content in the DC bus voltage and low frequency content in the DC system current. Based on these observations, an algorithm was developed using a high-speed data acquisition system that was able to accurately detect high impedance arcing events induced in a single-line system based on the frequency content of the DC bus voltage or the system current. Next, a multi-line, radial distribution system was researched to see if the arc location could be determined through the voltage information when multiple 'detectors' are present in the system. It was shown that a small, passive LC filter was sufficient to reliably isolate the fault to a single line in a multi-line distribution system. Of course, no modification is necessary if only the current information is used to locate the arc. However, data shows that it might be necessary to monitor both the system current and bus voltage to improve the chances of detecting and locating high impedance arcing faults

  12. System Security Authorization Agreement (SSAA) for the WIRE Archive and Research Facility

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Wide-Field Infrared Explorer (WIRE) Archive and Research Facility (WARF) is operated and maintained by the Department of Physics, USAF Academy. The lab is located in Fairchild Hall, 2354 Fairchild Dr., Suite 2A103, USAF Academy, CO 80840. The WARF will be used for research and education in support of the NASA Wide Field Infrared Explorer (WIRE) satellite, and for related high-precision photometry missions and activities. The WARF will also contain the WIRE preliminary and final archives prior to their delivery to the National Space Science Data Center (NSSDC). The WARF consists of a suite of equipment purchased under several NASA grants in support of WIRE research. The core system consists of a Red Hat Linux workstation with twin 933 MHz PIII processors, 1 GB of RAM, 133 GB of hard disk space, and DAT and DLT tape drives. The WARF is also supported by several additional networked Linux workstations. Only one of these (an older 450 Mhz PIII computer running Red Hat Linux) is currently running, but the addition of several more is expected over the next year. In addition, a printer will soon be added. The WARF will serve as the primary research facility for the analysis and archiving of data from the WIRE satellite, together with limited quantities of other high-precision astronomical photometry data from both ground- and space-based facilities. However, the archive to be created here will not be the final archive; rather, the archive will be duplicated at the NSSDC and public access to the data will generally take place through that site.

  13. A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems

    SciTech Connect

    Mohammed S. Agamy; Maja Harfman-Todorovic; Ahmed Elasser; Robert L. Steigerwald; Juan A. Sabate; Song Chi; Adam J. McCann; Li Zhang; Frank Mueller

    2012-09-01

    In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

  14. Reliability/safety analysis of a fly-by-wire system

    NASA Technical Reports Server (NTRS)

    Brock, L. D.; Goddman, H. A.

    1980-01-01

    An analysis technique has been developed to estimate the reliability of a very complex, safety-critical system by constructing a diagram of the reliability equations for the total system. This diagram has many of the characteristics of a fault-tree or success-path diagram, but is much easier to construct for complex redundant systems. The diagram provides insight into system failure characteristics and identifies the most likely failure modes. A computer program aids in the construction of the diagram and the computation of reliability. Analysis of the NASA F-8 Digital Fly-by-Wire Flight Control System is used to illustrate the technique.

  15. Design of a high voltage input - output ratio dc-dc converter dedicated to small power fuel cell systems

    NASA Astrophysics Data System (ADS)

    Béthoux, O.; Cathelin, J.

    2010-12-01

    Consuming chemical energy, fuel cells produce simultaneously heat, water and useful electrical power [J.M. Andújar, F. Segura, Renew. Sust. Energy Rev. 13, 2309 (2009)], [J. Larminie, A. Dicks, Fuel Cell Systems Explained, 2nd edn. (John Wiley & Sons, 2003)]. As a matter of fact, the voltage generated by a fuel cell strongly depends on both the load power demand and the operating conditions. Besides, as a result of many design aspects, fuel cells are low voltage and high current electric generators. On the contrary, electric loads are commonly designed for small voltage swing and a high V/I ratio in order to minimize Joule losses. Therefore, electric loads supplied by fuel cells are typically fed by means of an intermediate power voltage regulator. The specifications of such a power converter are to be able to step up the input voltage with a high ratio (a ratio of 10 is a classic situation) and also to work with an excellent efficiency (in order to minimize its size, its weight and its losses) [A. Shahin, B. Huang, J.P. Martin, S. Pierfederici, B. Davat, Energy Conv. Manag. 51, 56 (2010)]. This paper deals with the design of this essential ancillary device. It intends to bring out the best structure for fulfilling this function. Several dc-dc converters with large voltage step-up ratios are introduced. A topology based on a coupled inductor or tapped inductor is closely studied. A detailed modelling is performed with the purpose of providing designing rules. This model is validated with both simulation and implementation. The experimental prototype is based on the following specifications: the fuel cell output voltage ranges from a 50 V open-voltage to a 25 V rated voltage while the load requires a constant 250 V voltage. The studied coupled inductor converter is compared with a classic boost converter commonly used in this voltage elevating application. Even though the voltage regulator faces severe FC specifications, the measured efficiency reaches 96% at the rated power whereas conventional boost efficiency barely achieves 91.5% in the same operating conditions.

  16. Low-Cost Undergraduate Control Systems Experiments Using Microcontroller-Based Control of a DC Motor

    ERIC Educational Resources Information Center

    Gunasekaran, M.; Potluri, R.

    2012-01-01

    This paper presents low-cost experiments for a control systems laboratory module that is worth one and a third credits. The experiments are organized around the microcontroller-based control of a permanent magnet dc motor. The experimental setups were built in-house. Except for the operating system, the software used is primarily freeware or free…

  17. Low-Cost Undergraduate Control Systems Experiments Using Microcontroller-Based Control of a DC Motor

    ERIC Educational Resources Information Center

    Gunasekaran, M.; Potluri, R.

    2012-01-01

    This paper presents low-cost experiments for a control systems laboratory module that is worth one and a third credits. The experiments are organized around the microcontroller-based control of a permanent magnet dc motor. The experimental setups were built in-house. Except for the operating system, the software used is primarily freeware or free

  18. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: (1) 3.7 amps per wire; (2) bundle of 15 or more wires; (3) 70 C environment: and (4) vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  19. Cable Bundle Wire Derating

    NASA Technical Reports Server (NTRS)

    Lundquist, Ray A.; Leidecker, Henning

    1998-01-01

    The allowable operating currents of electrical wiring when used in the space vacuum environment is predominantly determined by the maximum operating temperature of the wire insulation. For Kapton insulated wire this value is 200 C. Guidelines provided in the Goddard Space Flight Center (GSFC) Preferred Parts List (PPL) limit the operating current of wire within vacuum to ensure the maximum insulation temperature is not exceeded. For 20 AWG wire, these operating parameters are: 3.7 amps per wire, bundle of 15 or more wires, 70 C environment, and vacuum of 10(exp -5) torr or less. To determine the behavior and temperature of electrical wire at different operating conditions, a thermal vacuum test was performed on a representative electrical harness of the Hubble Space Telescope (HST) power distribution system. This paper describes the test and the results.

  20. Comparative study of reference currents and DC bus voltage control for Three-Phase Four-Wire Four-Leg SAPF to compensate harmonics and reactive power with 3D SVM.

    PubMed

    Chebabhi, A; Fellah, M K; Kessal, A; Benkhoris, M F

    2015-07-01

    In this paper the performances of three reference currents and DC bus voltage control techniques for Three-Phase Four-Wire Four-Leg SAPF are compared for balanced and unbalanced load conditions. The main goals are to minimize the harmonics, reduce the magnitude of neutral current, eliminate the zero-sequence current components caused by single-phase nonlinear loads and compensate the reactive power, and on the other hand improve performances such as robustness, stabilization, trajectory pursuit, and reduce time response. The three techniques are analyzed mathematically and simulation results are compared. The techniques considered for comparative study are the PI Control, Sliding Mode Control and the Backstepping Control. Synchronous reference frame theory (SRF) in the dqo-axes is used to generate the reference currents, of the inverter. PMID:25704056

  1. Prospect of chip scale silicon photonics transceiver for high density multi-mode wiring system

    NASA Astrophysics Data System (ADS)

    Kurata, Kazuhiko; Suzuki, Yasuyuki; Kurihara, Mitsuru; Tokushima, Masatoshi; Hagihara, Yasuhiko; Ogura, Ichiro; Nakamura, Takahiro

    2016-03-01

    We propose high density multi-mode wiring system with chip scale silicon photonics transceiver. After review of concept and a discussion of overall design principles, design of a chip scale optical transceiver named Optical I/O core using silicon photonics is described.Experimental results with connected multimode fiber are presented. Finally, applications of optical I/O core and future prospects are introduced.

  2. Description of the SSF PMAD DC testbed control system data acquisition function

    NASA Technical Reports Server (NTRS)

    Baez, Anastacio N.; Mackin, Michael; Wright, Theodore

    1992-01-01

    The NASA LeRC in Cleveland, Ohio has completed the development and integration of a Power Management and Distribution (PMAD) DC Testbed. This testbed is a reduced scale representation of the end to end, sources to loads, Space Station Freedom Electrical Power System (SSF EPS). This unique facility is being used to demonstrate DC power generation and distribution, power management and control, and system operation techniques considered to be prime candidates for the Space Station Freedom. A key capability of the testbed is its ability to be configured to address system level issues in support of critical SSF program design milestones. Electrical power system control and operation issues like source control, source regulation, system fault protection, end-to-end system stability, health monitoring, resource allocation, and resource management are being evaluated in the testbed. The SSF EPS control functional allocation between on-board computers and ground based systems is evolving. Initially, ground based systems will perform the bulk of power system control and operation. The EPS control system is required to continuously monitor and determine the current state of the power system. The DC Testbed Control System consists of standard controllers arranged in a hierarchical and distributed architecture. These controllers provide all the monitoring and control functions for the DC Testbed Electrical Power System. Higher level controllers include the Power Management Controller, Load Management Controller, Operator Interface System, and a network of computer systems that perform some of the SSF Ground based Control Center Operation. The lower level controllers include Main Bus Switch Controllers and Photovoltaic Controllers. Power system status information is periodically provided to the higher level controllers to perform system control and operation. The data acquisition function of the control system is distributed among the various levels of the hierarchy. Data requirements are dictated by the control system algorithms being implemented at each level. A functional description of the various levels of the testbed control system architecture, the data acquisition function, and the status of its implementationis presented.

  3. DC current distribution mapping system of the solar panels using a HTS-SQUID gradiometer

    NASA Astrophysics Data System (ADS)

    Miyazaki, Shingo; Kasuya, Syohei; Mawardi Saari, Mohd; Sakai, Kenji; Kiwa, Toshihiko; Tsukamoto, Akira; Adachi, Seiji; Tanabe, Keiichi; Tsukada, Keiji

    2014-05-01

    Solar panels are expected to play a major role as a source of sustainable energy. In order to evaluate solar panels, non-destructive tests, such as defect inspections and response property evaluations, are necessary. We developed a DC current distribution mapping system of the solar panels using a High Critical Temperature Superconductor Superconducting Quantum Interference Device (HTS-SQUID) gradiometer with ramp edge type Josephson junctions. Two independent components of the magnetic fields perpendicular to the panel surface (∂Bz/∂x, ∂Bz/∂y) were detected. The direct current of the solar panel is visualized by calculating the composition of the two signal components, the phase angle, and mapping the DC current vector. The developed system can evaluate the uniformity of DC current distributions precisely and may be applicable for defect detection of solar panels.

  4. NASA/BAE Systems SpaceWire Efforts

    NASA Technical Reports Server (NTRS)

    Rakow, Glenn Parker; Schnurr, Richard G.; Kapcio, Paul

    2003-01-01

    This paper discusses the state of the NASA and BAE SYSTEMS developments using Spacewire. NASA has developed intellectual property that implements Spacewire in Register Transfer Level VHDL for a Spacewire link and router. This design has been extensively verified using directed tests from the Spacewire Standard and design specification, as well as being randomly tested to flush out hard to find bugs in the code. The high level features of the design will be discussed, including the support for multiple time code masters, which will be useful for the James Webb Space Telescope electrical architecture. This design is now ready to be targeted to FPGA's and ASICs. Target utilization and performance information will be presented for some spaceflight qualified FPGA's and a discussion of the ASIC implementations will be addressed. In particular, the BAE SYSTEMS ASIC will be highlighted which will be implemented in their 0.25 micron rad-hard line. The chip will implement a 4-port router with the ability to tie chips together to make larger routers without external glue logic. This part will have integrated LVDS driver/receivers, include a PLL and include skew control logic. It will be targeted to run at greater than 300 MHz and include the implementation for the proposed Spacewire transport layer. The need to provide a reliable transport mechanism for Spacewire has been identified by both NASA and ESA, who are attempting to define a transport layer standard that utilizes a low overhead, low latency connection oriented approach. The Transport layer needs to be implemented in hardware-to prevent bottlenecks.

  5. Wire Weight

    Wire weight is lowered to water surface to measure stage at a site. Levels are made to the wire weights elevation from known benchmarks to ensure correct readings. This wire weight is located along the Missouri River in Bismarck, ND....

  6. A simple digital-optical system to improve accuracy of hot-wire measurements

    NASA Astrophysics Data System (ADS)

    Gowree, E. R.; Atkin, C. J.; Gruppetta, S.

    2015-09-01

    A high precision traverse mechanism with micro-resolution was designed to capture accurately the velocity profile of the very thin turbulent attachment line on a swept body. To ensure that the traverse mechanism could position the hot wire reliably, a simple digital optical system was designed to check the performance of the traverse by measuring the displacement of the hot wire: a vertical displacement of 2.4?m was achievable and this could be further reduced to 0.6?m using micro-stepping. Due to the simplicity of the set-up it was equally useful for probe wall positioning and the velocity profiles captured clearly demonstrated that the optical set-up helped in resolving the near wall flow more accurately, regardless of the thinness of the boundary layer. The captured data compare well with the results from similar investigations, with arguably higher precision achieved.

  7. The influence of bracket design on frictional losses in the bracket/arch wire system.

    PubMed

    Schumacher, H A; Bourauel, C; Drescher, D

    1999-01-01

    In arch guided tooth movement, the essential role played by bracket configuration with respect to sliding friction has been recognized by the manufacturers, a fact which has had an increasing impact on the design and marketing of new bracket models in recent years. The aim of the present in-vitro study was to investigate the influence of different bracket designs on sliding mechanics. Five differently shaped stainless steel brackets (Discovery: Dentaurum, Damon SL: A-Company, Synergy: Rocky Mountain Orthodontics, Viazis bracket and Omni Arch appliance: GAC) were compared in the 0.022"-slot system. The Orthodontic Measurement and Simulation System (OMSS) was used to quantify the difference between applied force (NiTi coil spring, 1.0 N) and orthodontically effective force and to determine leveling losses occurring during the sliding process in arch guided tooth movement. Simulated canine retraction was performed using continuous arch wires with the dimensions 0.019" x 0.025" (Standard Steel, Unitek) and 0.020" x 0.020" (Ideal Gold, GAC). Comparison of the brackets revealed friction-induced losses ranging from 20 to 70%, with clear-cut advantages resulting from the newly developed bracket types. However, an increased tendency towards leveling losses in terms of distal rotation (maximum 15 degrees) or buccal root torque (maximum 20 degrees) was recorded, especially with those brackets giving the arch wire increased mobility due to their shaping or lack of ligature wire. PMID:10546416

  8. SpaceWire-based thermal-infrared imager system for asteroid sample return mission HAYABUSA2

    NASA Astrophysics Data System (ADS)

    Hihara, Hiroki; Iwase, Kaori; Sano, Junpei; Otake, Hisashi; Okada, Tatsuaki; Funase, Ryu; Kashikawa, Ryoichi; Higashino, Isamu; Masuda, Tetsuya

    2014-01-01

    A thermal-infrared (TIR) imager system is developed for HAYABUSA2, which is planned to be launched in 2014 and aims at sample-return from a C-class near-Earth asteroid 162173 (1999JU3) considered to contain organic or hydrated materials. The system consists of a TIR imager and digital electronics, which are used not only for the scientific investigation of physical properties of the asteroid surface, but also for the assessment of landing site selection and safe descent operation onto the asteroid surface with in situ measurement. TIR adopts an uncooled bolometer. Image operations such as multiple images summation, dark image subtraction, and the compensation of dead pixels are processed onboard. A processing module is connected to sensor interfaces through SpaceWire in order to provide deterministic processing time. Data compression is also provided to reduce the restriction of transmission time, which provides the equivalent compression ratio as JPEG2000 in 1/30 processing time in average. A high-speed data recorder is connected through SpaceWire in order to record TIR data in parallel with other sensor data. The modularity of SpaceWire enables us to use these as built devices for TIR and inherits the same design as the long-wavelength infrared imager developed for the Venus climate orbiter Akatsuki.

  9. PPM-based System for Guided Waves Communication Through Corrosion Resistant Multi-wire Cables

    NASA Astrophysics Data System (ADS)

    Trane, G.; Mijarez, R.; Guevara, R.; Pascacio, D.

    Novel wireless communication channels are a necessity in applications surrounded by harsh environments, for instance down-hole oil reservoirs. Traditional radio frequency (RF) communication schemes are not capable of transmitting signals through metal enclosures surrounded by corrosive gases and liquids. As an alternative to RF, a pulse position modulation (PPM) guided waves communication system has been developed and evaluated using a corrosion resistant 4H18 multi-wire cable, commonly used to descend electronic gauges in down-hole oil applications, as the communication medium. The system consists of a transmitter and a receiver that utilizes a PZT crystal, for electrical/mechanical coupling, attached to each extreme of the multi-wire cable. The modulator is based on a microcontroller, which transmits60 kHz guided wave pulses, and the demodulator is based on a commercial digital signal processor (DSP) module that performs real time DSP algorithms. Experimental results are presented, which were obtained using a 1m corrosion resistant 4H18multi-wire cable, commonly used with downhole electronic gauges in the oil sector. Although there was significant dispersion and multiple mode excitations of the transmitted guided wave energy pulses, the results show that data rates on the order of 500 bits per second are readily available employing PPM and simple communications techniques.

  10. Modified DSTATCOM Topology with Reduced DC Link Voltage for Reactive and Harmonic Power Compensation of Unbalanced Nonlinear Load in Distribution System

    NASA Astrophysics Data System (ADS)

    Geddada, Nagesh; Karanki, Srinivas B.; Mishra, Mahesh K.

    2014-06-01

    This paper proposes a modified four-leg distribution static compensator (DSTATCOM) topology for compensation of unbalanced and nonlinear loads in three-phase four-wire distribution system. DSTATCOM, connected in parallel to the load, supplies reactive and harmonic powers demanded by unbalanced nonlinear loads. In this proposed topology, the voltage source inverter (VSI) of DSTATCOM is connected to point of common coupling (point of interconnection of source, load, DSTATCOM) through interface inductor and series capacitance, unlike the conventional topology which consists of interface inductor alone. Load compensation with a lower value of input DC link voltage of VSI is possible in this modified topology compared to conventional topology. A comparative study on modified and conventional topologies in terms of voltage rating of inverter power switches, switching losses in VSI and power rating of input DC capacitor of VSI is presented. The detailed design aspects of DC link capacitor and interface series capacitor are also presented. The reference filter currents are generated using instantaneous symmetrical component theory and are tracked using hysteresis current control technique. A detailed simulation study is carried out, to compare the compensation performances of conventional, modified topologies using PSCAD simulator and experimental studies are done to validate the simulation results.

  11. A Control Method of a Small-Scale DC Power System Including Distributed Generators

    NASA Astrophysics Data System (ADS)

    Ito, Youichi; Yang, Zhongqing; Akagi, Hirofumi

    This paper describes a dc micro-grid system interconnecting distributed power generators. The system consists of five generation and control units; a solar-cell generation unit, a wind-turbine generation unit, a battery energy-storage unit, a flywheel power-leveling unit, and an ac grid-interconnecting power control unit. The control method is proposed for suppressing the circulating current by detecting only the dc grid voltage. This method brings high reliability, high-flexibility and maintenance-free operation to the system. The method pays attention to dc output voltage performance of each unit. Each of the power control unit and the energy-storage unit is controlled to act as a voltage source with imaginery impedance. On the other hand, each of the two generation units is controlled to act as a current source. The power-leveling unit is controlled to act as a current source having the function of frequency selectivity like a high-pass filter. A 10-kW prototype system verifies experimentally the validity and effectiveness of the proposed control method for the dc-grid system.

  12. Design and test experience with a triply redundant digital fly-by-wire control system

    NASA Technical Reports Server (NTRS)

    Szalai, K. J.; Felleman, P. G.; Gera, J.; Glover, R. D.

    1976-01-01

    A triplex digital fly-by-wire flight control system was developed and then installed in a NASA F-8C aircraft to provide fail-operative, full authority control. Hardware and software redundancy management techniques were designed to detect and identify failures in the system. Control functions typical of those projected for future actively controlled vehicles were implemented. This paper describes the principal design features of the system, the implementation of computer, sensor, and actuator redundancy management, and the ground test results. An automated test program to verify sensor redundancy management software is also described.

  13. Design and construction evaluation of a photovoltaic DC LED lighting system

    NASA Astrophysics Data System (ADS)

    Bhamidipati, Jyotsna

    2008-08-01

    The market demand for commercialization of Photovoltaic (PV) systems depends a lot on the reliability, efficiency and performance of various components within the system. PV panels produce DC power when exposed to sunlight, and an inverter converts this to AC power in a typical solar powered building. Though, PV lighting has existed for a long time it hasn't been very effective, as incandescent light sources were commonly used which are inefficient. Today fluorescent fixtures are mostly used with PV's due to its high efficacy. Light-emitting diodes present a new vision to energy efficiency in lighting design with their low energy consumption. Current research predicts improved efficiencies of LED light fixtures and their commercial use is a few years away. LEDs which operate on DC voltages when coupled with photovoltaics can be a simple PV lighting application and a sustainable solution with potential for payback. This research evaluates the design and construction of a photovoltaic DC LED lighting system for a solar house at Pennsylvania State University. A detailed cost and payback analysis of a PV DC LED lighting system is presented in this research. PV output simulations for the solar house are presented. Results presented in this research indicate that the Solid state lighting market is evolving rapidly and that LED's are a choice in stand-alone photovoltaic DC lighting systems. The efficiency and the cost-effectiveness of such systems would however improve in the coming years with research and development now focused on PV systems and on Solid state lighting technologies.

  14. Research study on multi-KW DC distribution system

    NASA Technical Reports Server (NTRS)

    Berkery, E. A.

    1975-01-01

    Power distribution system noise and transient stress on switchgear in large space vehicle power systems were investigated in terms of the effect of flight designs of long power distribution cables on load interface EMI requirements. A fifty meter cable pair was simulated to study interactions between the cable, load, and power source terminations. Power system noise characteristics were evaluated based on current spacecraft data, interface hardware filter designs, and power cable parameters. Parametric approaches were defined for evaluating switching transients at various distribution voltage levels. It is concluded that the state-of-the-art semiconductor switches represent a viable approach toward the implementation of power system design with distribution voltages of 120 VDC or less. The interface definition and design for the bus control unit was updated to be consistent with the established requirements.

  15. Design of Performance Driven Self-Tuning PID Control Systems and It's Application for DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Ohnishi, Yoshihiro; Ikemoto, Takahiro; Yamamoto, Toru

    This paper proposes an adaptive PID controller which is driven by current control performance. The calculations of the PID parameters are based on the generalized minimum variance control(GMVC) algorithm. The current control performance is obtained in an online manner over a user-specified time-window with some overlap. The retuning of PID parameters are only carried out when controller performance deteriorates below a user-specified threshold. Experimental evaluations on the voltage control of the DC-DC converter demonstrates the practicality and utility of this idea.

  16. 77 FR 74347 - Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for Printing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-14

    ....S. Office of Personnel Management (OPM) issued an interim rule (77 FR 41247) to abolish the... rule published on July 13, 2012 (77 FR 41427), amending 5 CFR part 532, is adopted as final without... RIN 3206-AM59 Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule...

  17. Evaluation of DC electric field measurement by the double probe system aboard the Geotail spacecraft

    NASA Astrophysics Data System (ADS)

    Kasaba, Y.; Hayakawa, H.; Ishisaka, K.; Okada, T.; Matsuoka, A.; Mukai, T.; Takei, Y.

    We summarize the characteristics of the DC electric field measurement by the double probe system, PANT and EFD-P, aboard Geotail. The accuracy and correction factors for the gain (effective length) and off-set, which depends on ambient plasma conditions are provided.

  18. Prospects of long-distance HTS DC power transmission systems

    NASA Astrophysics Data System (ADS)

    Romashov, M. A.; Sytnikov, V. E.; Shakarian, Y. G.; Ivanov, Y. V.

    2014-05-01

    Continual improvement of technologies for the safe use of power resources is a key to sustainable development of a human society. In particular, high-temperature superconductivity (HTS) should be used to meet the growing needs of the electric-power industry. It is known that HTS power cables allow us to increase the level of transmitted energy to several GW at voltage of 66-110 kV. HTS power cables of a coaxial design are almost ideal non-polluting system shielding electromagnetic field. In the present work we have tried to analyze various configurations of HTS power transmission systems, estimate the cable transmission capacitance depending on distance, and characterize reliability and efficiency of the systems.

  19. The state-of-the-art of dc power distribution systems/components for space applications

    NASA Technical Reports Server (NTRS)

    Krauthamer, S.

    1988-01-01

    This report is a survey of the state of the art of high voltage dc systems and components. This information can be used for consideration of an alternative secondary distribution (120 Vdc) system for the Space Station. All HVdc components have been prototyped or developed for terrestrial, aircraft, and spacecraft applications, and are applicable for general space application with appropriate modification and qualification. HVdc systems offer a safe, reliable, low mass, high efficiency and low EMI alternative for Space Station secondary distribution.

  20. Fallback level concepts for conventional and by-wire automotive brake systems

    NASA Astrophysics Data System (ADS)

    Retzer, H.; Mishra, R.; Ball, A.; Schmidt, K.

    2012-05-01

    Brake-by-wire represents the replacement of traditional brake components such as pumps, hoses, fluids, brake boosters, and master cylinders by electronic sensors and actuators. The different design of these brake concepts poses new challenges for the automotive industry with regard to availability and fallback levels in comparison to standard conventional brake systems. This contribution focuses on the development of appropriate fallback level concepts. Hardware-in-the-loop (HIL) techniques and field trials will be used to investigate the performance and the usability of such systems.

  1. Software Development for a CompactRIO-Based Wire Scanner Control and Data Acquisition SYstem

    SciTech Connect

    Sedillo, James Daniel

    2012-05-16

    The Beam Diagnostics and Instrumentation Team at the Los Alamos Neutron Science Center is developing a wire scanner data acquisition and control system with a National Instrument's compactRIO at its core. For this application, the compactRIO controller not only requires programming the FPGA and RT computer internal to the compactRIO, but also requires programming a client computer and a touch panel display. This article will summarize the hardware interfaces and describe the software design approach utilized for programming and interfacing the four systems together in order to fulfill the design requirements and promote reliable interoperability.

  2. Seating patterns on the Washington, DC Metro Rail System.

    PubMed

    Trinkoff, A M

    1985-06-01

    Research on human tolerance in crashes has found that rear-facing seating offers increased protection over forward seating. However, rearward seats are only available in limited settings. In this study, passengers were observed and seating preferences recorded on the Washington Metropolitan Rail System (Metro). Only 25 per cent of adults faced rearward compared to 66 per cent of children. Since children appear willing to face rearward, rear-facing seating in school buses and other vehicles might be acceptable to them and provide safety benefits as well. PMID:4003633

  3. Magnification of starting torques of dc motors by maximum power point trackers in photovoltaic systems

    NASA Technical Reports Server (NTRS)

    Appelbaum, Joseph; Singer, S.

    1989-01-01

    Direct current (dc) motors are used in terrestrial photovoltaic (PV) systems such as in water-pumping systems for irrigation and water supply. Direct current motors may also be used for space applications. Simple and low weight systems including dc motors may be of special interest in space where the motors are directly coupled to the solar cell array (with no storage). The system will operate only during times when sufficient insolation is available. An important performance characteristic of electric motors is the starting to rated torque ratio. Different types of dc motors have different starting torque ratios. These ratios are dictated by the size of solar cell array, and the developed motor torque may not be sufficient to overcome the load starting torque. By including a maximum power point tracker (MPPT) in the PV system, the starting to rated torque ratio will increase, the amount of which depends on the motor type. The starting torque ratio is calculated for the permanent magnet, series and shunt excited dc motors when powered by solar cell arrays for two cases: with and without MPPT's. Defining a motor torque magnification by the ratio of the motor torque with an MPPT to the motor torque without an MPPT, a magnification of 3 was obtained for the permanent magnet motor and a magnification of 7 for both the series and shunt motors. The effect of the variation of solar insolation on the motor starting torque was covered. All motor types are less sensitive to insolation variation in systems including MPPT's as compared to systems with MPPT's. The analysis of this paper will assist the PV system designed to determine whether or not to include an MPPT in the system for a specific motor type.

  4. Basic Wiring.

    ERIC Educational Resources Information Center

    Kaltwasser, Stan; And Others

    This module is the first in a series of three wiring publications; it serves as the foundation for students enrolled in a wiring program. It is a prerequisite to either "Residential Wiring" or "Commercial and Industrial Wiring." The module contains 16 instructional units that cover the following topics: occupational introduction; general safety;…

  5. Two-level system dynamics in amorphous dielectrics probed with a dc electric field

    NASA Astrophysics Data System (ADS)

    Khalil, Moe; Gladchenko, Sergiy; Stoutimore, M. J. A.; Wellstood, F. C.; Osborn, K. D.

    2012-02-01

    We report loss in a thin-film dc electric-field tunable LC resonator built with superconducting aluminum and silicon nitride dielectric. To measure the loss we continually apply microwave power on resonance and monitor the transmitted power. At milli-Kelvin temperatures, loss is limited by two-level systems in the dielectric which are saturated with high microwave excitation power. Measurements show that a sudden change of applied dc field causes the dielectric loss to increase to the intrinsic low power loss tangent of the dielectric. We study the subsequent relaxation of the loss tangent caused by two-level system saturation and interactions. We discuss how this arises from the dynamics of a distribution of two-level system defects and compare it with new theoretical work on interacting two-level systems.

  6. SpaceWire- Based Control System Architecture for the Lightweight Advanced Robotic Arm Demonstrator [LARAD

    NASA Astrophysics Data System (ADS)

    Rucinski, Marek; Coates, Adam; Montano, Giuseppe; Allouis, Elie; Jameux, David

    2015-09-01

    The Lightweight Advanced Robotic Arm Demonstrator (LARAD) is a state-of-the-art, two-meter long robotic arm for planetary surface exploration currently being developed by a UK consortium led by Airbus Defence and Space Ltd under contract to the UK Space Agency (CREST-2 programme). LARAD has a modular design, which allows for experimentation with different electronics and control software. The control system architecture includes the on-board computer, control software and firmware, and the communication infrastructure (e.g. data links, switches) connecting on-board computer(s), sensors, actuators and the end-effector. The purpose of the control system is to operate the arm according to pre-defined performance requirements, monitoring its behaviour in real-time and performing safing/recovery actions in case of faults. This paper reports on the results of a recent study about the feasibility of the development and integration of a novel control system architecture for LARAD fully based on the SpaceWire protocol. The current control system architecture is based on the combination of two communication protocols, Ethernet and CAN. The new SpaceWire-based control system will allow for improved monitoring and telecommanding performance thanks to higher communication data rate, allowing for the adoption of advanced control schemes, potentially based on multiple vision sensors, and for the handling of sophisticated end-effectors that require fine control, such as science payloads or robotic hands.

  7. Preliminary system design study for a digital fly-by-wire flight control system for an F-8C aircraft

    NASA Technical Reports Server (NTRS)

    Seacord, C. L.; Vaughn, D. K.

    1976-01-01

    The design of a fly-by-wire control system having a mission failure probability of less than one millionth failures per flight hour is examined. Emphasis was placed on developing actuator configurations that would improve the system performance, and consideration of the practical aspects of sensor/computer and computer/actuator interface implementation. Five basic configurations were defined as appropriate candidates for the F-8C research aircraft. Options on the basic configurations were included to cover variations in flight sensors, redundancy levels, data transmission techniques, processor input/output methods, and servo actuator arrangements. The study results can be applied to fly by wire systems for transport aircraft in general and the space shuttle.

  8. Description and Flight Test Results of the NASA F-8 Digital Fly-by-Wire Control System

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A NASA program to develop digital fly-by-wire (DFBW) technology for aircraft applications is discussed. Phase I of the program demonstrated the feasibility of using a digital fly-by-wire system for aircraft control through developing and flight testing a single channel system, which used Apollo hardware, in an F-8C airplane. The objective of Phase II of the program is to establish a technology base for designing practical DFBW systems. It will involve developing and flight testing a triplex digital fly-by-wire system using state-of-the-art airborne computers, system hardware, software, and redundancy concepts. The papers included in this report describe the Phase I system and its development and present results from the flight program. Man-rated flight software and the effects of lightning on digital flight control systems are also discussed.

  9. Nonlinear control of voltage source converters in AC-DC power system.

    PubMed

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations. PMID:24906895

  10. Optimal Design of Litz Wire Coils With Sandwich Structure Wirelessly Powering an Artificial Anal Sphincter System.

    PubMed

    Ke, Lei; Yan, Guozheng; Yan, Sheng; Wang, Zhiwu; Li, Xiaoyang

    2015-07-01

    Transcutaneous energy transfer system (TETS) is widely used to energize implantable biomedical devices. As a key part of the TETS, a pair of applicable coils with low losses, high unloaded Q factor, and strong coupling is required to realize an efficient TETS. This article presents an optimal design methodology of planar litz wire coils sandwiched between two ferrite substrates wirelessly powering a novel mechanical artificial anal sphincter system for treating severe fecal incontinence, with focus on the main parameters of the coils such as the wire diameter, number of turns, geometry, and the properties of the ferrite substrate. The theoretical basis of optimal power transfer efficiency in an inductive link was analyzed. A set of analytical expressions are outlined to calculate the winding resistance of a litz wire coil on ferrite substrate, taking into account eddy-current losses, including conduction losses and induction losses. Expressions that describe the geometrical dimension dependence of self- and mutual inductance are derived. The influence of ferrite substrate relative permeability and dimensions is also considered. We have used this foundation to devise an applicable coil design method that starts with a set of realistic constraints and ends with the optimal coil pair geometries. All theoretical predictions are verified with measurements using different types of fabricated coils. The results indicate that the analysis is useful for optimizing the geometry design of windings and the ferrite substrate in a sandwich structure as part of which, in addition to providing design insight, allows speeding up the system efficiency-optimizing design process. PMID:25808086

  11. Automatic ac/dc thermal voltage converter and ac voltage calibration system

    NASA Astrophysics Data System (ADS)

    Lentner, K. J.; Flach, D. R.; Bell, B. A.

    1984-11-01

    An automatic ac/dc difference calibration system is described which uses direct measurement of thermoelement emfs. In addition to ac/dc difference testing, the system can be used to measure some important characteristics of thermoelements, as well as to calibrate ac voltage calibrators and precision voltmeters. The system operates over a frequency range from 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kv. For all voltages the total measurement uncertainties expected (including the uncertainty of the specific reference thermal converters used) were 50 parts per million (ppm) at frequencies from 20 Hz to 20 kHz, inclusive, and 100 ppm at higher frequencies up to 100 kHz.

  12. An automatic AC/DC thermal voltage converter and AC voltage calibration system

    NASA Astrophysics Data System (ADS)

    Lentner, K. J.; Flach, D. R.; Bell, B. A.

    1985-10-01

    An automatic ac/dc difference calibration system is described which uses direct measurement of thermoelement emfs. In addition to ac/dc difference testing, the system can be used to measure some important characteristics of thermoelements, as well as to calibrate ac voltage calibrators and precision voltmeters. The system operates over a frquency range from 20 Hz to 100 kHz, covering the voltage range from 0.5 V to 1 kv. For all voltages the total measurement uncertainties expected (including the uncertainty of the specific reference thermal converters used) were 50 parts per million (ppm) at frequencies from 20 Hz to 20 kHz, inclusive, and 100 ppm at higher frequencies up to 100 kHz.

  13. Brushless DC motor control system responsive to control signals generated by a computer or the like

    NASA Technical Reports Server (NTRS)

    Packard, Douglas T. (Inventor); Schmitt, Donald E. (Inventor)

    1987-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The rotor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor may be regulated by applying a separate control signal to each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  14. Brushless DC motor control system responsive to control signals generated by a computer or the like

    NASA Technical Reports Server (NTRS)

    Packard, D. T. (Inventor)

    1985-01-01

    A control system for a brushless DC motor responsive to digital control signals is disclosed. The motor includes a multiphase wound stator and a permanent magnet rotor. The motor is arranged so that each phase winding, when energized from a DC source, will drive the rotor through a predetermined angular position or step. A commutation signal generator responsive to the shaft position provides a commutation signal for each winding. A programmable control signal generator such as a computer or microprocessor produces individual digital control signals for each phase winding. The control signals and commutation signals associated with each winding are applied to an AND gate for that phase winding. Each gate controls a switch connected in series with the associated phase winding and the DC source so that each phase winding is energized only when the commutation signal and the control signal associated with that phase winding are present. The motor shaft may be advanced one step at a time to a desired position by applying a predetermined number of control signals in the proper sequence to the AND gates and the torque generated by the motor be regulated by applying a separate control signal and each AND gate which is pulse width modulated to control the total time that each switch connects its associated winding to the DC source during each commutation period.

  15. The SpaceWire-based thermal infrared imager system for asteroid sample return mission HAYABUSA2

    NASA Astrophysics Data System (ADS)

    Otake, Hisashi; Okada, Tatsuaki; Funase, Ryu; Hihara, Hiroki; Sano, Junpei; Iwase, Kaori; Kashikawa, Ryoichi; Higashino, Isamu; Masuda, Tetsuya

    2013-09-01

    Thermal infrared imager system is developed for HAYABUSA2, which is planned to be launched in 2014 and aims at sample-return from a C class near-Earth asteroid 1999JU3 considered to contain organic or hydrated materials. The system consists of a thermal-infrared imager (TIR) and a digital electronics, which is used not only for the scientific investigation of physical properties of the asteroid surface, but also for the assessment of landing site selection and safe descent operation onto the asteroid surface with in situ measurement. Since round trip communication time between the asteroid and the Earth is more than thirty minutes, onboard automatic data processing function and high speed data recording capability are provided to exploit the limited downlink capacity which is up to 32kbps. TIR adopts an uncooled bolometer with 320 x 240 effective pixels. Image operations as multiple images summation, dark image subtraction, and the compensation of dead pixels are processed onboard. A processing module is connected to sensor interfaces through SpaceWire in order to provide deterministic processing time. Data compression is also provided to reduce restriction on storage capacity and operation time, which provides the equivalent compression ratio as JPEG2000 in 1/30 processing time in average. A high speed data recorder is also connected through SpaceWire in 50Mbps in order to record TIR data in parallel with other sensor data. The modularity of SpaceWire enables to use as built devices for TIR and inherits the same design as the long-wavelength infrared imager developed for the Venus climate orbiter Akatsuki.

  16. Investigation of Microelectromechanical Switches for Next Generation DC Power Distribution System

    NASA Astrophysics Data System (ADS)

    Femi, R.; Clement, Shibu; Agrawal, Anita; Prince, A. Amalin

    2014-12-01

    This paper investigates the application of microelectromechanical system (MEMS) switches for DC power distribution system. Traditional electromechanical switches, solid state switches and solid state switch array are studied and simulated to understand their characteristics. Performance and characteristics of MEMS switches are reviewed and identified that electrostatically actuated MEMS switches are suitable for DC power applications. Scalable total cross tied (TCT) array configuration using MEMS switches has been proposed. The proposed configuration is suitable for variable voltage/current rating. Arc-less behavior of the switch configuration is analyzed using modified Paschen's curve. 400 V/6 A system is considered for the simulation and comparative study. The simulated result of the proposed MEMS switch array configuration is compared with the traditional switches. The comparative study shows that the proposed switch array configuration gives better performance in terms of voltage drop, leakage current, power loss, arc and size. This can be used in DC power system protection, circuit breaking, battery protection and smart grid load switching applications.

  17. DC transport in two-dimensional electron systems under strong microwave illumination

    NASA Astrophysics Data System (ADS)

    Chakraborty, Shantanu

    At low temperature (T) and weak magnetic field ( B), two dimensional electron systems (2DES) can exhibit strong 1/ B-periodic resistance oscillations on application of sufficiently strong microwave radiation. These oscillations are known as microwave induced resistance oscillations (MIROs), MIROs appearing near cyclotron resonance (CR) and its harmonics involve single photon processes and are called integer MIROs while the oscillations near CR subharmonics require multiphoton processes and are called fractional MIROs. Similar strong 1/B periodic resistance oscillations can occur due to strong dc current, and are known as Hall-field resistance oscillations (HIROs). Oscillations also occur for a combination of microwave radiation and strong dc current. In one prominent theory of MIROs, known as the displacement model, electrons make impurity-assisted transitions into higher or lower Landau levels by absorbing or emitting one or more (N) photons. In the presence of combined strong dc current and microwave radiation, electrons make transitions between Landau levels by absorbing or emitting photons followed by a space transition along the applied dc bias. The object of the dissertation is to explore how the different resistance oscillations area affected by strong microwave radiation when multiphoton processes are relevant. We used a coplanar waveguide (CPW) structure deposited on the sample, as opposed to simply placing the sample near the termination of a waveguide as is more the usual practice in this field. The CPW allows us to estimate the AC electric field (EAC) at the sample. In much of the work presented in this thesis we find that higher Nprocesses supersede the competing lower N processes as microwave power is increased. We show this in the presence and in the absence of a strong dc electric field. Finally, we look at the temperature evolution of fractional MIROs to compare the origin of the fractional MIROs with that of integer MIROs.

  18. Characteristic Analysis of DC Electric Railway Systems with Superconducting Power Cables Connecting Power Substations

    NASA Astrophysics Data System (ADS)

    Ohsaki, H.; Matsushita, N.; Koseki, T.; Tomita, M.

    2014-05-01

    The application of superconducting power cables to DC electric railway systems has been studied. It could leads to an effective use of regenerative brake, improved energy efficiency, effective load sharing among the substations, etc. In this study, an electric circuit model of a DC feeding system is built and numerical simulation is carried out using MATLAB-Simulink software. A modified electric circuit model with an AC power grid connection taken into account is also created to simulate the influence of the grid connection. The analyses have proved that a certain amount of energy can be conserved by introducing superconducting cables, and that electric load distribution and concentration among the substations depend on the substation output voltage distribution.

  19. MIDAS, prototype Multivariate Interactive Digital Analysis System, phase 1. Volume 3: Wiring diagrams

    NASA Technical Reports Server (NTRS)

    Kriegler, F. J.; Christenson, D.; Gordon, M.; Kistler, R.; Lampert, S.; Marshall, R.; Mclaughlin, R.

    1974-01-01

    The Midas System is a third-generation, fast, multispectral recognition system able to keep pace with the large quantity and high rates of data acquisition from present and projected sensors. A principal objective of the MIDAS Program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughput. The hardware and software generated in Phase I of the overall program are described. The system contains a mini-computer to control the various high-speed processing elements in the data path and a classifier which implements an all-digital prototype multivariate-Gaussian maximum likelihood decision algorithm operating at 2 x 100,000 pixels/sec. Sufficient hardware was developed to perform signature extraction from computer-compatible tapes, compute classifier coefficients, control the classifier operation, and diagnose operation. The MIDAS construction and wiring diagrams are given.

  20. Pose measurement base on machine vision for the aircraft model in wire-driven parallel suspension system

    NASA Astrophysics Data System (ADS)

    Chen, Yi-feng; Wu, Liao-ni; Yue, Sui-lu; Lin, Qi

    2013-03-01

    In wind tunnel tests, the pose of the aircraft model in wire-driven parallel suspension system (WDPSS) is determined by driving several wires. Pose measurement is very important for the study of WDPSS. Using machine vision technology, Monocular Vision Measurement System has been constructed to estimate the pose of the aircraft model by applying a camera calibration, by extracting corresponding control points for the aircraft model, and by applying several homogeneous transformations. This article describes the programs of the measurement system, measurement principle and data processing methods which is based on HALCON to achieve the Solution of the pose of aircraft model. Through experiments, practical feasibility of the system is validated.

  1. Front-end electronics and data acquisition system for a multi-wire 3D gas tracker

    NASA Astrophysics Data System (ADS)

    Łojek, K.; Rozpȩdzik, D.; Bodek, K.; Perkowski, M.; Severijns, N.

    2015-12-01

    This paper presents the design and implementation of the front-end electronics and the data acquisition (DAQ) system for readout of multi-wire drift chambers (MWDC). Apart of the conventional drift time measurement the system delivers the hit position along the wire utilizing the charge division technique. The system consists of preamplifiers, and analog and digital boards sending data to a back-end computer via an Ethernet interface. The data logging software formats the received data and enables an easy access to the data analysis software. The use of specially designed preamplifiers and peak detectors allows the charge-division readout of the low resistance signal wire. The implication of the charge-division circuitry onto the drift time measurement was studied and the overall performance of the electronic system was evaluated in dedicated off-line tests.

  2. A study of the parallel algorithm for large-scale DC simulation of nonlinear systems

    NASA Astrophysics Data System (ADS)

    Cortés Udave, Diego Ernesto; Ogrodzki, Jan; Gutiérrez de Anda, Miguel Angel

    Newton-Raphson DC analysis of large-scale nonlinear circuits may be an extremely time consuming process even if sparse matrix techniques and bypassing of nonlinear models calculation are used. A slight decrease in the time required for this task may be enabled on multi-core, multithread computers if the calculation of the mathematical models for the nonlinear elements as well as the stamp management of the sparse matrix entries are managed through concurrent processes. This numerical complexity can be further reduced via the circuit decomposition and parallel solution of blocks taking as a departure point the BBD matrix structure. This block-parallel approach may give a considerable profit though it is strongly dependent on the system topology and, of course, on the processor type. This contribution presents the easy-parallelizable decomposition-based algorithm for DC simulation and provides a detailed study of its effectiveness.

  3. Surface and interface phonon-polaritons in freestanding quantum well wire systems of polar ternary mixed crystals

    NASA Astrophysics Data System (ADS)

    Yan, C. L.; Bao, J.; Yan, Z. W.

    2016-03-01

    The surface and interface phonon-polaritons in freestanding rectangular quantum well wire systems consisting of polar ternary mixed crystals are investigated in the modified random-element-isodisplacement model and the Born-Huang approximation, based on the Maxwell's equations with the boundary conditions. The numerical results of the surface and interface phonon-polariton frequencies as functions of the wave-vector, geometric structure, and the composition of the ternary mixed crystals in GaAs/AlxGa1-xAs and ZnxCd1-xSe/ZnSe quantum well wire systems are obtained and discussed. It is shown that there are 10 and 8 branches of surface and interface phonon-polaritons in the two quantum well wire systems respectively. The effects of the "two-mode" and "one-mode" behaviors of the ternary mixed crystals on the surface and interface phonon-polariton modes are shown in the dispersion curves.

  4. A wire scanning based method for geometric calibration of high resolution CT system

    NASA Astrophysics Data System (ADS)

    Jiang, Ruijie; Li, Guang; Gu, Ning; Chen, Gong; Luo, Shouhua

    2015-03-01

    This paper is about geometric calibration of the high resolution CT (Computed Tomography) system. Geometric calibration refers to the estimation of a set of parameters that describe the geometry of the CT system. Such parameters are so important that a little error of them will degrade the reconstruction images seriously, so more accurate geometric parameters are needed in the higher-resolution CT systems. But conventional calibration methods are not accurate enough for the current high resolution CT system whose resolution can reach sub-micrometer or even tens of nanometers. In this paper, we propose a new calibration method which has higher accuracy and it is based on the optimization theory. The superiority of this method is that we build a new cost function which sets up a relationship between the geometrical parameters and the binary reconstruction image of a thin wire. When the geometrical parameters are accurate, the cost function reaches its maximum value. In the experiment, we scanned a thin wire as the calibration data and a thin bamboo stick as the validation data to verify the correctness of the proposed method. Comparing with the image reconstructed with the geometric parameters calculated by using the conventional calibration method, the image reconstructed with the parameters calculated by our method has less geometric artifacts, so it can verify that our method can get more accurate geometric calibration parameters. Although we calculated only one geometric parameter in this paper, the geometric artifacts are still eliminated significantly. And this method can be easily generalized to all the geometrical parameters calibration in fan-beam or cone-beam CT systems.

  5. LANSCE-R WIRE-SCANNER ANALOG FRONT-END ELECTRONICS

    SciTech Connect

    Gruchalla, Michael E.

    2011-01-01

    A new AFE is being developed for the new LANSCE-R wire-scanner systems. The new AFE is implemented in a National Instruments Compact RIO (cRIO) module installed a BiRa 4U BiRIO cRIO chassis specifically designed to accommodate the cRIO crate and all the wire-scanner interface, control and motor-drive electronics. A single AFE module provides interface to both X and Y wire sensors using true DC coupled transimpedance amplifiers providing collection of the wire charge signals, real-time wire integrity verification using the normal dataacquisition system, and wire bias of 0V to +/-50V. The AFE system is designed to accommodate comparatively long macropulses (>1ms) with high PRF (>120Hz) without the need to provide timing signals. The basic AFE bandwidth is flat from true DC to 50kHz with a true first-order pole at 50kHz. Numeric integration in the cRIO FPGA provides real-time pulse-to-pulse numeric integration of the AFE signal to compute the total charge collected in each macropulse. This method of charge collection eliminates the need to provide synchronization signals to the wire-scanner AFE while providing the capability to accurately record the charge from long macropulses at high PRF.

  6. Development of Automotive Communication Based Real-Time Systems - A Steer-by-Wire Case Study

    NASA Astrophysics Data System (ADS)

    Klobedanz, Kay; Kuznik, Christoph; Elfeky, Ahmed; Müller, Wolfgang

    Safety-critical automotive systems must fulfill hard real-time constraints to guarantee their reliability and safety requirements. In the context of network-based electronics systems, high-level timing requirements have to be carefully mastered and traced throughout the whole development process. In this paper, we outline the management of scheduling-specific timing information by the application of a steer-by-wire design example. We apply the principles of the AUTOSAR-compliant Timing Augmented Description Language (TADL) following the methodology introduced by the TIMMO project[2]. Focus of the example will be the identification of end-to-end timing constraints and their refinement by means of stimuli-response event chains.

  7. Development of hand rehabilitation system for paralysis patient - universal design using wire-driven mechanism.

    PubMed

    Yamaura, Hiroshi; Matsushita, Kojiro; Kato, Ryu; Yokoi, Hiroshi

    2009-01-01

    We have developed a hand rehabilitation system for patients suffering from paralysis or contracture. It consists of two components: a hand rehabilitation machine, which moves human finger joints with motors, and a data glove, which provides control of the movement of finger joints attached to the rehabilitation machine. The machine is based on the arm structure type of hand rehabilitation machine; a motor indirectly moves a finger joint via a closed four-link mechanism. We employ a wire-driven mechanism and develop a compact design that can control all three joints (i.e., PIP, DIP and MP ) of a finger and that offers a wider range of joint motion than conventional systems. Furthermore, we demonstrate the hand rehabilitation process, finger joints of the left hand attached to the machine are controlled by the finger joints of the right hand wearing the data glove. PMID:19963950

  8. Description of the control system design for the SSF PMAD DC testbed

    NASA Technical Reports Server (NTRS)

    Baez, Anastacio N.; Kimnach, Greg L.

    1991-01-01

    The Power Management and Distribution (PMAD) DC Testbed Control System for Space Station Freedom was developed using a top down approach based on classical control system and conventional terrestrial power utilities design techniques. The design methodology includes the development of a testbed operating concept. This operating concept describes the operation of the testbed under all possible scenarios. A unique set of operating states was identified and a description of each state, along with state transitions, was generated. Each state is represented by a unique set of attributes and constraints, and its description reflects the degree of system security within which the power system is operating. Using the testbed operating states description, a functional design for the control system was developed. This functional design consists of a functional outline, a text description, and a logical flowchart for all the major control system functions. Described here are the control system design techniques, various control system functions, and the status of the design and implementation.

  9. An overview of power electronics applications in fuel cell systems: DC and AC converters.

    PubMed

    Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  10. An Overview of Power Electronics Applications in Fuel Cell Systems: DC and AC Converters

    PubMed Central

    Ali, M. S.; Kamarudin, S. K.; Masdar, M. S.; Mohamed, A.

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  11. Micron size laser-wire system at the ATF extraction line, recent results and ATF-II upgrade

    NASA Astrophysics Data System (ADS)

    Aryshev, A.; Blair, G. A.; Boogert, S. T.; Boorman, G.; Bosco, A.; Corner, L.; Deacon, L.; Delerue, N.; Foster, B.; Gannaway, F.; Hayano, H.; Howell, D.; Karataev, P.; Nevay, L.; Newman, M.; Senanayake, R.; Terunuma, N.; Urakawa, J.; Walczak, R.

    2010-11-01

    The KEK Accelerator test facility (ATF) extraction line laser-wire system has been upgraded last year allowing the measurement of micron scale transverse size electron beams. The last measurements using the upgraded system from recent operation at the ATF are presented, demonstrating raw measurements of order 3 μm RMS. The main component contributions to this measurement are also discussed.

  12. Magnification of starting torques of dc motors by maximum power point trackers in photovoltaic systems

    NASA Technical Reports Server (NTRS)

    Appelbaum, J.; Singer, S.

    1989-01-01

    A calculation of the starting torque ratio of permanent magnet, series, and shunt-excited dc motors powered by solar cell arrays is presented for two cases, i.e., with and without a maximum-power-point tracker (MPPT). Defining motor torque magnification by the ratio of the motor torque with an MPPT to the motor torque without an MPPT, a magnification of 3 for the permanent magnet motor and a magnification of 7 for both the series and shunt motors are obtained. The study also shows that all motor types are less sensitive to solar insolation variation in systems including MPPTs as compared to systems without MPPTs.

  13. Stability of large DC power systems using switching converters, with application to the international space station

    NASA Technical Reports Server (NTRS)

    Manners, B.; Gholdston, E. W.; Karimi, K.; Lee, F. C.; Rajagopalan, J.; Panov, Y.

    1996-01-01

    As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) and its contractor team led by Boeing Defense & Space Group has placed a great deal of emphasis on designing for system and load stability. To achieve this goal, the team has expended considerable effort deriving a dear concept on defining system stability in both a general sense and specifically with respect to the space station. The ISS power system presents numerous challenges with respect to system stability, such as high power, complex sources and undefined loads. To complicate these issues, source and load components have been designed in parallel by three major subcontractors (Boeing, Rocketdyne, and McDonnell Douglas) with interfaces to both sources and loads being designed in different countries (Russia, Japan, Canada, Europe, etc.). These issues, coupled with the program goal of limiting costs, have proven a significant challenge to the program. As a result, the program has derived an impedance specification approach for system stability. This approach is based on the significant relationship between source and load impedances and the effect of this relationship on system stability. This approach is limited in its applicability by the theoretical and practical limits on component designs as presented by each system segment. As a result, the overall approach to system stability implemented by the ISS program consists of specific hardware requirements coupled with extensive system analysis and hardware testing. Following this approach, the ISS program plans to begin construction of the world's largest orbiting power system in 1997.

  14. Drive laser system for the DC-SRF photoinjector at Peking University

    NASA Astrophysics Data System (ADS)

    Zhi-Wen, Wang; Sen-Lin, Huang; Lin, Lin; Gang, Zhao; Sheng-Wen, Quan; Ke-Xin, Liu; Jia-Er, Chen

    2016-01-01

    Photoinjectors are widely used for linear accelerators as electron sources to generate high-brightness electron beams. The drive laser, which determines the timing structure and quality of the electron beam, is a crucial component of a photoinjector. A new drive laser system has been designed and constructed for the upgraded 3.5-cell DC-SRF photoinjector at Peking University. The drive laser system consists of a 1064 nm laser oscillator, a four-stage amplifier, second and fourth harmonic generators, an optical system to transfer the UV pulses to the photocathode, and a synchronization system. The drive laser system has been successfully applied during stable operation of the DC-SRF photoinjector and its performance meets requirements. A 266 nm laser with an average power close to 1 W can be delivered to illuminate the Cs2Te photocathode and the instability is less than 5% for long time operation. The design considerations for improving the UV laser quality, a detailed description of the laser system, and its performance are presented in this paper. Supported by National Basic Research Project (973) (2011CB808302, 2011CB808304)

  15. The Effects of Operational Parameters on a Mono-wire Cutting System: Efficiency in Marble Processing

    NASA Astrophysics Data System (ADS)

    Yilmazkaya, Emre; Ozcelik, Yilmaz

    2016-02-01

    Mono-wire block cutting machines that cut with a diamond wire can be used for squaring natural stone blocks and the slab-cutting process. The efficient use of these machines reduces operating costs by ensuring less diamond wire wear and longer wire life at high speeds. The high investment costs of these machines will lead to their efficient use and reduce production costs by increasing plant efficiency. Therefore, there is a need to investigate the cutting performance parameters of mono-wire cutting machines in terms of rock properties and operating parameters. This study aims to investigate the effects of the wire rotational speed (peripheral speed) and wire descending speed (cutting speed), which are the operating parameters of a mono-wire cutting machine, on unit wear and unit energy, which are the performance parameters in mono-wire cutting. By using the obtained results, cuttability charts for each natural stone were created on the basis of unit wear and unit energy values, cutting optimizations were performed, and the relationships between some physical and mechanical properties of rocks and the optimum cutting parameters obtained as a result of the optimization were investigated.

  16. Final Results of the Protected Superficial Femoral Artery Trial Using the FilterWire EZ System

    SciTech Connect

    Mueller-Huelsbeck, Stefan; Paulsen, Friedrich; Heller, Martin; Jahnke, Thomas

    2010-12-15

    The purpose of this study was to evaluate the safety and efficacy of debris-capture for distal protection using the FilterWire EZ Embolic Protection System (Boston Scientific, Mountain View, CA) with the additional aim to further define the incidence of distal embolization during superficial femoral artery (SFA) interventions. A prospective, single-centre registry was designed to evaluate the performance of the FilterWire EZ in capturing debris during standard SFA percutaneous intervention. The PRO-RATA study included 30 patients suitable for PTA (Fontaine IIb to III or Rutherford I to II classification). The primary end points were occurrence of distal embolization or decreased runoff, improvement in ankle-brachial index ankle-brachial index (ABI) after the procedure, and number of filters containing emboli. Secondary end points included major adverse events (i.e., procedure- or device-related death and/or clinical target lesion revascularisation), device delivery, deployment success, and incidence of embolic recovery (patients with device success exhibiting embolic protection in the filter). Procedural success was determined as {<=}30% residual stenosis with no worsening of distal runoff as determined on angiography. A total of 29 patients (age 66.2 {+-} 12 years; total no. of limbs = 30; total no. of lesions = 30) suitable for PTA were enrolled in the study between February 2007 and March 2008. There were 26 patients with claudication (Fontaine IIB) and 3 patients with stage IV peripheral vascular disease. In one patient, lesions in both legs were treated. No procedural or device-related complications occured. The average degree of stenosis was 86 {+-} 7%. Stenosis length ranged from 8 to 88 mm. The average degree of residual stenosis was 10 {+-} 10%. ABI improved from 0.56 {+-} 0.16 to 0.92 {+-} 0.19 (P < 0.05). No restenosis or dissection was seen at 1-month ultrasound follow-up. Macroscopic debris was found in 27 of 30 filters of all distal protection devices used in all 29 patients. Debris particle size ranged from 90 to 2000 {mu}m (1200 {+-} 640). Histological debris analysis showed platelets, erythrocytes, inflammatory cells, extracellular matrix, and cholesterol as being the major components of emboli. Additional immunochemistry showed no correlation between lesion morphology and debris components. The FilterWire EZ is easy and safe to handle. The system caused no complications. In all cases, macroscopic debris was captured. Using a distal protection device during femoropopliteal interventions has the potential to prevent migration of debris, which may be important for high-risk patients with limited distal runoff.

  17. Wire stripper

    NASA Technical Reports Server (NTRS)

    Economu, M. A. (Inventor)

    1978-01-01

    An insulation stripper is described which is especially useful for shielded wire, the stripper including a first pair of jaws with blades extending substantially perpendicular to the axis of the wire, and a second pair of jaws with blades extending substantially parallel to the axis of the wire. The first pair of jaws is pressed against the wire so the blades cut into the insulation, and the device is turned to form circumferential cuts in the insulation. Then the second pair of jaws is pressed against the wire so the blades cut into the insulation, and the wire is moved through the device to form longitudinal cuts that permit easy removal of the insulation. Each of the blades is located within the concave face of a V-block, to center the blades on the wire and to limit the depth of blade penetration.

  18. Impact of stray charge on interconnect wire via probability model of double-dot system

    NASA Astrophysics Data System (ADS)

    Xiangye, Chen; Li, Cai; Qiang, Zeng; Xinqiao, Wang

    2016-02-01

    The behavior of quantum cellular automata (QCA) under the influence of a stray charge is quantified. A new time-independent switching paradigm, a probability model of the double-dot system, is developed. Superiority in releasing the calculation operation is presented by the probability model compared to previous stray charge analysis utilizing ICHA or full-basis calculation. Simulation results illustrate that there is a 186-nm-wide region surrounding a QCA wire where a stray charge will cause the target cell to switch unsuccessfully. The failure is exhibited by two new states' dominating the target cell. Therefore, a bistable saturation model is no longer applicable for stray charge analysis. Project supported by the National Natural Science Foundation of China (No. 61172043) and the Key Program of Shaanxi Provincial Natural Science for Basic Research (No. 2011JZ015).

  19. Laser measuring system for incremental assemblies. [measuring wire-wrapped frame assemblies in spark chambers

    NASA Technical Reports Server (NTRS)

    Etzel, J. G.; Munford, J. A. (Inventor)

    1981-01-01

    Wire-wrapped frame assemblies used in spark chambers and the like can be measured using a system which utilizes a laser, an interferometer, and a retroreflector to precisely measure distance. A light source and a photodetector are located adjacent the incremental assembly and mounted on a movable carriage. The interferometer is also mounted on the movable carriage, while the laser and retroreflector are positioned at either end of the carriage track. The carriage is moved along one edge of the incremental assembly between the retroreflector and the laser, and as the carriage is moved, the light from the light source to the photodetector is interrupted. This produces a trigger command to a control unit which in turn causes a distance measurement to be made. A printout is provided for each sampling trigger command to list such items as ideal position, actual position and amount of error.

  20. Reliability analysis of the F-8 digital fly-by-wire system

    NASA Technical Reports Server (NTRS)

    Brock, L. D.; Goodman, H. A.

    1981-01-01

    The F-8 Digital Fly-by-Wire (DFBW) flight test program intended to provide the technology for advanced control systems, giving aircraft enhanced performance and operational capability is addressed. A detailed analysis of the experimental system was performed to estimated the probabilities of two significant safety critical events: (1) loss of primary flight control function, causing reversion to the analog bypass system; and (2) loss of the aircraft due to failure of the electronic flight control system. The analysis covers appraisal of risks due to random equipment failure, generic faults in design of the system or its software, and induced failure due to external events. A unique diagrammatic technique was developed which details the combinatorial reliability equations for the entire system, promotes understanding of system failure characteristics, and identifies the most likely failure modes. The technique provides a systematic method of applying basic probability equations and is augmented by a computer program written in a modular fashion that duplicates the structure of these equations.

  1. Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets

    SciTech Connect

    Kennth Marken

    2006-08-11

    The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford Instruments and Siemens. Between the project start and that date a substantial shift in the MRI marketplace occurred, with rapid growth for systems at higher fields (1.5 T and above) and a consequent decline in the low field market (<1.0 T). While the project aim appeared technically attainable at that time, the conclusion was reached that the system and market economics do not warrant additional investment. The program was redirected to develop BSCCO 2212 multifilament wire development for high field superconducting magnets for NMR and other scientific research upon an agreement between DOE and Oxford Instruments, Superconducting Technology. The work t took place between September, 2004 and the project end in early 2006 was focused on 2212 multifilamentary wire. This report summarizes the technical achievements both in 2212 dip coated for an HTS MRI system and in BSCCO 2212 multifilamentary wire for high field magnets.

  2. Load converter interactions with the secondary system in the Space Station Freedom power management and distribution dc test bed

    NASA Technical Reports Server (NTRS)

    Lebron, Ramon C.

    1992-01-01

    The NASA LeRC in Cleveland, Ohio, is responsible for the design, development, and assembly of the Space Station Freedom (SSF) Electrical Power System (EPS). In order to identify and understand system level issues during the SSF program design and development phases, a system Power Management and Distribution (PMAD) dc test bed was assembled. Some of the objectives of this test bed facility are the evaluation of, system efficiency, power quality, system stability, and system protection and reconfiguration schemes. In order to provide a realistic operating scenario, dc Load Converter Units are used in the PMAD dc test bed to characterize the user interface with the power system. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. This final regulation is required on the actual space station because the majority of user loads will require voltage levels different from the secondary bus voltage. This paper describes the testing of load converters in an end to end system environment (from solar array to loads) where their interactions and compatibility with other system components are considered. Some of the system effects of interest that are presented include load converters transient behavior interactions with protective current limiting switchgear, load converters ripple effects, and the effects of load converter constant power behavior with protective features such as foldback.

  3. Load converter interactions with the secondary system in the Space Station Freedom power management and distribution DC test bed

    NASA Technical Reports Server (NTRS)

    Lebron, Ramon C.

    1992-01-01

    The NASA LeRC in Cleveland, Ohio, is responsible for the design, development, and assembly of the Space Station Freedom (SSF) Electrical Power System (EPS). In order to identify and understand system level issues during the SSF Program design and development phases, a system Power Management and Distribution (PMAD) DC test bed was assembled. Some of the objectives of this test bed facility are the evaluation of, system efficiency, power quality, system stability, and system protection and reconfiguration schemes. In order to provide a realistic operating scenario, dc Load Converter Units are used in the PMAD dc test bed to characterize the user interface with the power system. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. This final regulation is required on the actual space station because the majority of user loads will require voltage levels different from the secondary bus voltage. This paper describes the testing of load converters in an end to end system environment (from solar array to loads) where their interactions and compatibility with other system components are considered. Some of the system effects of interest that are presented include load converters transient behavior interactions with protective current limiting switchgear, load converters ripple effects, and the effects of load converter constant power behavior with protective features such as foldback.

  4. Magnetic navigation system used successfully to cross a crushed stent in a bifurcation that failed with conventional wires.

    PubMed

    Ramcharitar, Steve; Patterson, Mark S; van Geuns, Robert-Jan; Serruys, Patrick W

    2007-05-01

    Bifurcation lesions can be technically demanding to manage, and even in the era of drug eluting stents, their procedural success is variable. The use of the crush technique followed by "kissing" balloon postdilatation has been shown to improve the overall outcome. However, crossing the crushed stent is essential to allow performance of a final dilatation with "kissing" balloons and is regarded as the main Achilles' heel of this technique. In this report, we describe the first reported, planned procedure to use a magnetic navigation system to steer a wire through the crushed stent to use "kissing" balloons that had previously failed with conventional wires. PMID:17191212

  5. A COAXIAL TE011 CAVITY AND A SYSTEM TO MEASURE DC AND RF PROPERTIES OF SUPERCONDUCTORS

    SciTech Connect

    Gianluigi Ciovati; Peter Kneisel; Ganapati Rao Myneni; Larry Turlington; Gary Slack; Michael Morrone; William Clemens; Richard Bundy; Thomas Elliott; Jayanta Mondal

    2008-01-23

    A coaxial niobium cavity has been designed and built where the center conductor consists of a removable sample. In addition, a system to measure properties such as magnetization, penetration depth, critical temperature and thermal conductivity on the same cylindrical sample has been designed and built. The purpose of this effort is to investigate possible correlations between DC and RF properties of superconductors. In this contribution, the design of the various components is discussed and the test results on a niobium sample obtained so far are presented.

  6. The Influence of Pd-Doped Au Wire Bonding on HAZ Microstructure and Looping Profile in Micro-Electromechanical Systems (MEMS) Packaging

    NASA Astrophysics Data System (ADS)

    Ismail, Roslina; Omar, Ghazali; Jalar, Azman; Majlis, Burhanuddin Yeop

    2015-07-01

    Wire bonding processes has been widely adopted in micro-electromechanical systems (MEMS) packaging especially in biomedical devices for the integration of components. In the first process sequence in wire bonding, the zone along the wire near the melted tips is called the heat-affected zone (HAZ). The HAZ plays an important factor that influenced the looping profiles of wire bonding process. This paper investigates the effect of dopants on microstructures in the HAZ. One precent palladium (Pd) was added to the as-drawn 4N gold wire and annealed at 600C. The addition of Pd was able to moderate the grain growth in the HAZ by retarding the heat propagation to the wire. In the formation of the looping profile, the first bending point of the looping is highly associated with the length of the HAZ. The alloyed gold wire (2N gold) has a sharp angle at a distance of about 30 m from the neck of the wire with a measured bending radius of about 40 mm and bending angle of about 40 clockwise from vertical axis, while the 4N gold wire bends at a longer distance. It also shows that the HAZ for 4N gold is longer than 2N gold wire.

  7. Earth to space dc to dc power transmission system utilizing a microwave beam as source of energy for electric propelled interorbital vehicles

    NASA Technical Reports Server (NTRS)

    Brown, W. C.

    1985-01-01

    The paper contributes to the credibility of an electric propelled interorbital transportation system by introducing a new low-mass source of continuous dc power for electric propulsion and illustrating how the source can be economically tied to an electric utility on earth by an electronically steered microwave beam. The new thin-film rectenna, which functions as the receiving end of an earth-to-space microwave power transmission system is described. It is easily fabricated, is over 80 percent efficient, has a specific mass of no more than 2 kilograms per kilowatt of continuous dc power output, and is well adapted for deployment in space. The paper then describes a complete system consisting of the interorbital vehicle and the microwave power transmission system that supplies it with power. A design scenario is used to obtain performance data from the system in terms of vehicle transfer times, payload fractions, and costs. Electric energy costs are found to be less than $1000 per kilogram of payload delivered to geosynchronous orbit from low-earth orbit.

  8. Metallic Glass Wire Based Localization of Kinesin/Microtubule Bio-molecular Motility System

    NASA Astrophysics Data System (ADS)

    Kim, K.; Sikora, A.; Yaginuma, S.; Nakayama, K. S.; Nakazawa, H.; Umetsu, M.; Hwang, W.; Teizer, W.

    2014-03-01

    We report electrophoretic accumulation of microtubules along metallic glass (Pd42.5Cu30Ni7.5P20) wires free-standing in solution. Microtubules are dynamic cytoskeletal filaments. Kinesin is a cytoskeletal motor protein. Functions of these bio-molecules are central to various dynamic cellular processes. Functional artificial organization of bio-molecules is a prerequisite for transferring their native functions into device applications. Fluorescence microscopy at the individual-microtubule level reveals microtubules aligning along the wire axis during the electrophoretic migration. Casein-treated electrodes are effective for releasing trapped microtubules upon removal of the external field. Furthermore, we demonstrate gliding motion of microtubules on kinesin-treated metallic glass wires. The reversible manner in the local adsorption of microtubules, the flexibility of wire electrodes, and the compatibility between the wire electrode and the bio-molecules are beneficial for spatio-temporal manipulation of the motility machinery in 3 dimensions.

  9. 47 CFR 68.213 - Installation of other than “fully protected” non-system simple customer premises wiring.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... non-system simple customer premises wiring. 68.213 Section 68.213 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) CONNECTION OF TERMINAL EQUIPMENT TO THE... or protective circuitry to one another, and to carrier-installed facilities if installed...

  10. 47 CFR 68.213 - Installation of other than “fully protected” non-system simple customer premises wiring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Installation of other than âfully protectedâ non-system simple customer premises wiring. 68.213 Section 68.213 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) CONNECTION OF TERMINAL EQUIPMENT TO THE TELEPHONE NETWORK Terminal Equipment...

  11. Photosynthesis and antioxidant defense system of Gynura Bicolor DC grown at different elevated CO2 levels

    NASA Astrophysics Data System (ADS)

    Wang, Minjuan; Liu, Hong; Fu, Yuming

    Atmospheric carbon dioxide concentration [CO _{2}] will increase in the future and will affect global climate and ecosystem productivity. However, this is not clearly an area that requires further study on the most appropriate [CO _{2}] selection for plant growth and quality in a closed, controlled environment. The aim of this study was to determine the variation of photosynthetic characteristics and antioxidant status under five CO _{2} concentration (400, 800, 1200, 2000 and 3000 umol mol (-1) ) on the leaf of Gynura bicolor DC. Here the results show that net photosynthetic rate(Pn), Chl content, edible biomass(EB), leaf blade width(LBW), root weight(RW), fructose(Fru) and sucrose(Suc) of Gynura bicolor DC increased under elevated [CO _{2}] of 800 umol mol (-1) , 1200 umol mol (-1) and 2000 umol mol (-1) . On the contrary, photosynthesis and biomass production declined significantly at 3000 umol mol (-1) CO _{2}, While Lipid peroxidation (LPO), malondialdehyde (MDA) and hydrogen peroxide (H _{2}O _{2}) achieved the highest levels. Furthermore, the contents of glutathione (GSH), vitamin C (VC), and vitamin E (VE), and total antioxidant capacity (T-AOC), the activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) reached the highest level at 2000 umol mol ({-1) }CO _{2}. Results imply that a significant increase in growth and antioxidant defense system of Gynura bicolor DC occurred under 800-2000 umol mol (-1) of CO _{2} concentration provided a theoretical basis for the application for plants selection in Bioregeneration Life Support System (BLSS) and a closed controlled environment.

  12. Study of a guarded electrode system in the dc conductivity measurement of insulating liquid

    NASA Astrophysics Data System (ADS)

    Zhou, Yuan; Hao, Miao; Chen, George; Wilson, Gordon; Jarman, Paul

    2014-07-01

    The design and choice of an electrode system is important in dc conductivity measurement of insulating liquid. In this paper, the electric field distribution of an electrode system which consists of two parallel circular metallic electrodes and a guard electrode has been studied using Comsol Multiphysics software. A new parameter, which is not yet involved in current standards, the edge radius, has been mentioned in the literature formerly and is currently discussed in a CIGRE working group. In this paper, the influence of this parameter has been investigated by means of field calculation. As seen from the simulating result, there are regions in the vicinity of the edges of the guard and measuring electrode that are under high electric field. If the edges of these two electrodes are sharp, the maximum electric field in the test cell will be much higher than the average field between the measuring electrode and the high voltage electrode. An empirical equation has been proposed to calculate this maximum field. The classic correction expression for an effective radius has been re-evaluated with the edge radius being taken into account. Experimental work has been performed to confirm this conclusion. Three kinds of mineral oils with different ageing times have been tested under the dc field using a guarded electrode system and the electric strengths of these oils have been estimated. A recommendation has been made to current standards in insulating liquid measurement.

  13. [Evaluation of a DC pulsed magnetic tracking system in neurosurgical navigation: technique, accuracies, and influencing factors].

    PubMed

    Suess, Olaf; Suess, Silke; Mularski, Sven; Kühn, Björn; Picht, Thomas; Schönherr, Sven; Kombos, Theodoros

    2007-06-01

    Navigation systems are useful instruments in cranial neurosurgery. For specification of position, so-called sensor-based navigation techniques use: (a) a signal emitter that generates a defined electromagnetic field in the area of the operation site; and (b) small sensors that detect the position of various operating instruments in the electromagnetic field. For a long time, owing to a lack of clinical data and long-term studies, electromagnetic systems have been regarded as error-prone and imprecise. With the development of a pulsed direct current (DC) technique, precision levels can now be reached that are comparable with those of established optical and mechanical measuring procedures. However, it must be noted that the influence on the measuring accuracy within the operating field increases with increasing susceptibility of the various metals used in the operating theatre (titaniumDC pulsed magnetic tracking system were investigated in more than 200 cases. PMID:17561783

  14. Three dimensional finite element methods: Their role in the design of DC accelerator systems

    NASA Astrophysics Data System (ADS)

    Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W.

    2013-04-01

    High Voltage Engineering has designed, built and tested a 2 MV dual irradiation system that will be applied for radiation damage studies and ion beam material modification. The system consists of two independent accelerators which support simultaneous proton and electron irradiation (energy range 100 keV - 2 MeV) of target sizes of up to 300 × 300 mm2. Three dimensional finite element methods were used in the design of various parts of the system. The electrostatic solver was used to quantify essential parameters of the solid-state power supply generating the DC high voltage. The magnetostatic solver and ray tracing were used to optimize the electron/ion beam transport. Close agreement between design and measurements of the accelerator characteristics as well as beam performance indicate the usefulness of three dimensional finite element methods during accelerator system design.

  15. Solid State Remote Power Controllers for high voltage DC distribution systems

    NASA Technical Reports Server (NTRS)

    Billings, W. W.; Sundberg, G. R.

    1977-01-01

    Presently, hybrid Remote Power Controllers (RPC's) are in production and prototype units are available for systems utilizing 28VDC, 120VDC, 115VAC/400 Hz and 230VAC/400 Hz. This paper describes RPC development in a new area of application: HVDC distribution systems utilizing 270/300VDC. Two RPC current ratings, 1 amp and 2 amps, were selected for development as they are adequate to control 90% of projected system loads. The various aspects and trade-offs encountered in circuit development are discussed with special focus placed on the circuits that see the duress of the high dc potentials. The comprehensive evaluation tests are summarized which confirmed the RPC compliance with the specification and with system/load compatibility requirements. In addition, present technology status and new applications are summarized.

  16. Three dimensional finite element methods: Their role in the design of DC accelerator systems

    SciTech Connect

    Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W.

    2013-04-19

    High Voltage Engineering has designed, built and tested a 2 MV dual irradiation system that will be applied for radiation damage studies and ion beam material modification. The system consists of two independent accelerators which support simultaneous proton and electron irradiation (energy range 100 keV - 2 MeV) of target sizes of up to 300 Multiplication-Sign 300 mm{sup 2}. Three dimensional finite element methods were used in the design of various parts of the system. The electrostatic solver was used to quantify essential parameters of the solid-state power supply generating the DC high voltage. The magnetostatic solver and ray tracing were used to optimize the electron/ion beam transport. Close agreement between design and measurements of the accelerator characteristics as well as beam performance indicate the usefulness of three dimensional finite element methods during accelerator system design.

  17. DC source assemblies

    DOEpatents

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  18. Impact of quasi-dc currents on three-phase distribution transformer installations. Power Systems Technology Program

    SciTech Connect

    McConnell, B.W.; Barnes, P.R.; Tesche, F.M.; Schafer, D.A.

    1992-06-01

    This report summarizes a series of tests designed to determine the response of quasi-dc currents on three-phase power distribution transformers for electric power systems. In general, if the dc injection is limited to the primary side of a step-down transformer, significant harmonic distortion is noted and an increase in the reactive power demand results. For dc injection on the secondary (load) side of the step-down transformer the harmonic content at the secondary side is quite high and saturation occurs with a relatively low level of dc injection; however, the reactive power demand is significantly lower. These tests produced no apparent damage to the transformers. Transformer damage is dependent on the duration of the dc excitation, the level of the excitation, and on thermal characteristics of the transfer. The transformer response time is found to be much shorter than seen in power transformer tests at lower dc injection levels. This shorter response time suggests that the response time is strongly dependent on the injected current levels, and that higher levels of dc injection for shorter durations could produce very high reactive power demands and harmonic distortion within a few tenths of a second. The added reactive power load could result in the blowing of fuses on the primary side of the transformer for even moderate dc injection levels, and neutral currents are quite large under even low-level dc injection. This ``smoking neutral`` results in high-level harmonic injection into equipment via the neutral and in possible equipment failure.

  19. Investigations of some aspects of the spray process in a single wire arc plasma spray system using high speed camera

    NASA Astrophysics Data System (ADS)

    Tiwari, N.; Sahasrabudhe, S. N.; Tak, A. K.; Barve, D. N.; Das, A. K.

    2012-02-01

    A high speed camera has been used to record and analyze the evolution as well as particle behavior in a single wire arc plasma spray torch. Commercially available systems (spray watch, DPV 2000, etc.) focus onto a small area in the spray jet. They are not designed for tracking a single particle from the torch to the substrate. Using high speed camera, individual particles were tracked and their velocities were measured at various distances from the spray torch. Particle velocity information at different distances from the nozzle of the torch is very important to decide correct substrate position for the good quality of coating. The analysis of the images has revealed the details of the process of arc attachment to wire, melting of the wire, and detachment of the molten mass from the tip. Images of the wire and the arc have been recorded for different wire feed rates, gas flow rates, and torch powers, to determine compatible wire feed rates. High speed imaging of particle trajectories has been used for particle velocity determination using time of flight method. It was observed that the ripple in the power supply of the torch leads to large variation of instantaneous power fed to the torch. This affects the velocity of the spray particles generated at different times within one cycle of the ripple. It is shown that the velocity of a spray particle depends on the instantaneous torch power at the time of its generation. This correlation was established by experimental evidence in this paper. Once the particles leave the plasma jet, their forward speeds were found to be more or less invariant beyond 40 mm up to 500 mm from the nozzle exit.

  20. Investigations of some aspects of the spray process in a single wire arc plasma spray system using high speed camera.

    PubMed

    Tiwari, N; Sahasrabudhe, S N; Tak, A K; Barve, D N; Das, A K

    2012-02-01

    A high speed camera has been used to record and analyze the evolution as well as particle behavior in a single wire arc plasma spray torch. Commercially available systems (spray watch, DPV 2000, etc.) focus onto a small area in the spray jet. They are not designed for tracking a single particle from the torch to the substrate. Using high speed camera, individual particles were tracked and their velocities were measured at various distances from the spray torch. Particle velocity information at different distances from the nozzle of the torch is very important to decide correct substrate position for the good quality of coating. The analysis of the images has revealed the details of the process of arc attachment to wire, melting of the wire, and detachment of the molten mass from the tip. Images of the wire and the arc have been recorded for different wire feed rates, gas flow rates, and torch powers, to determine compatible wire feed rates. High speed imaging of particle trajectories has been used for particle velocity determination using time of flight method. It was observed that the ripple in the power supply of the torch leads to large variation of instantaneous power fed to the torch. This affects the velocity of the spray particles generated at different times within one cycle of the ripple. It is shown that the velocity of a spray particle depends on the instantaneous torch power at the time of its generation. This correlation was established by experimental evidence in this paper. Once the particles leave the plasma jet, their forward speeds were found to be more or less invariant beyond 40 mm up to 500 mm from the nozzle exit. PMID:22380128

  1. Transfissural Route Used for Preoperative Localization of Small Pulmonary Lesions with a Short Hook Wire and Suture System

    SciTech Connect

    Iguchi, Toshihiro Hiraki, Takao Gobara, Hideo Fujiwara, Hiroyasu Matsui, Yusuke; Sugimoto, Seiichiro Toyooka, Shinichi Oto, Takahiro Miyoshi, Shinichiro; Kanazawa, Susumu

    2015-02-15

    PurposeWe retrospectively evaluated the results of the transfissural route for preoperative localization with a short hook wire and suture system for video-assisted thoracoscopic surgery (VATS).MethodsEleven patients with 11 tumors underwent CT-guided transfissural placement of a hook wire before VATS. This route was selected for all patients, because the distance between the tumor and interlobar fissure was much shorter than the required distance traversed using the conventional approach. Complications were evaluated using the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.0.ResultsThe hook wire was successfully placed using the transfissural route in all but one case. Of these ten successful placements, two tumors needed a second puncture for optimal placement, because the CT scan showed that the first hook wire was not properly placed in the lung. In one patient, we did not attempt replacement after the first placement was incorrect. In ten successful procedures, the mean distance traversed in the parenchyma of the unaffected lung lobe was 27.9 mm. The distance between the pleura and placed hook wire was significantly shorter than the estimated distance between the pleura and hook wire using the conventional route (mean 16.3 vs. 40.9 mm; P = 0.0002). Grade 1 adverse events occurred (11 pneumothoraxes and 4 pulmonary hemorrhages). No grade 2 or higher adverse event was observed.ConclusionsThe transfissural route used for preoperative localization before VATS is useful for selected patients because this route may allow for more limited lung parenchyma resection.

  2. Intelligent dc-dc Converter Technology Developed and Tested

    NASA Technical Reports Server (NTRS)

    Button, Robert M.

    2001-01-01

    The NASA Glenn Research Center and the Cleveland State University have developed a digitally controlled dc-dc converter to research the benefits of flexible, digital control on power electronics and systems. Initial research and testing has shown that conventional dc-dc converters can benefit from improved performance by using digital-signal processors and nonlinear control algorithms.

  3. Performance analysis of radiation cooled dc transmission lines for high power space systems

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.

    1985-01-01

    As space power levels increase to meet mission objectives and also as the transmission distance between power source and load increases, the mass, volume, power loss, and operating voltage and temperature become important system design considerations. This analysis develops the dependence of the specific mass and percent power loss on hte power and voltage levels, transmission distance, operating temperature and conductor material properties. Only radiation cooling is considered since the transmission line is assumed to operate in a space environment. The results show that the limiting conditions for achieving low specific mass, percent power loss, and volume for a space-type dc transmission line are the permissible transmission voltage and operating temperature. Other means to achieve low specific mass include the judicious choice of conductor materials. The results of this analysis should be immediately applicable to power system trade-off studies including comparisons with ac transmission systems.

  4. Towards a molecular QCA wire: simulation of write-in and read-out systems

    NASA Astrophysics Data System (ADS)

    Pulimeno, A.; Graziano, M.; Demarchi, D.; Piccinini, G.

    2012-11-01

    Among emerging beyond CMOS technologies Molecular Quantum Dot Cellular Automata (MQCA) are estimated as extremely promising for computational purposes. The elementary nanoelectronic devices are molecular systems in which the binary encoding is provided by the charge localization within a molecule. As a consequence, there is no current flowing among the cells and power dissipation is dramatically reduced. We study a new real molecule that was synthesized ad hoc for this technology. Differently with respect to previous contributions, this study has the aim of assessing the realistic properties of this molecule in a perspective experimental system based on a molecular wire principle. We use a combination of ab initio calculations and molecular dynamics simulations and analyze the molecule behavior when specific electric fields are applied to move the electrons inside the molecule in order to force a logic state. Our results allowed us (i) to asses the molecule behavior and to explore the working points of our experimental system for the write-in, (ii) to introduce in this scenario new metrics for studying and using these new devices from an electronic point of view, (iii) to give a perspective and to define design constraints for possible experimental solutions eligible for issue of molecule state read-out.

  5. Field Trial on a Rack-mounted DC Power Supply System with 80-Ah Lithium-ion Batteries

    NASA Astrophysics Data System (ADS)

    Matsushima, Toshio

    Using an industrial lithium-ion battery that has higher energy density than conventional valve-regulated lead-acid batteries, a rack-mounted DC-power-supply system was assembled and tested at a base transceiver station (BTS) offering actual services. A nominal output voltage and maximum output current of the system is 53.5V and 20A, respectively. An 80-Ah lithium-ion battery composed of 13 cells connected in series was applied in the system and maintained in a floating charge method. The DC-power-supply system was installed in a 19-inch power rack in the telecommunications equipment box at BTS. The characteristics of the 80Ah lithium-ion battery, specifications of the DC-power-supply system and field-test results were shown in this paper.

  6. Next Generation Wiring

    NASA Technical Reports Server (NTRS)

    Medelius, Petro; Jolley, Scott; Fitzpatrick, Lilliana; Vinje, Rubiela; Williams, Martha; Clayton, LaNetra; Roberson, Luke; Smith, Trent; Santiago-Maldonado, Edgardo

    2007-01-01

    Wiring is a major operational component on aerospace hardware that accounts for substantial weight and volumetric space. Over time wire insulation can age and fail, often leading to catastrophic events such as system failure or fire. The next generation of wiring must be reliable and sustainable over long periods of time. These features will be achieved by the development of a wire insulation capable of autonomous self-healing that mitigates failure before it reaches a catastrophic level. In order to develop a self-healing insulation material, three steps must occur. First, methods of bonding similar materials must be developed that are capable of being initiated autonomously. This process will lead to the development of a manual repair system for polyimide wire insulation. Second, ways to initiate these bonding methods that lead to materials that are similar to the primary insulation must be developed. Finally, steps one and two must be integrated to produce a material that has no residues from the process that degrades the insulating properties of the final repaired insulation. The self-healing technology, teamed with the ability to identify and locate damage, will greatly improve reliability and safety of electrical wiring of critical systems. This paper will address these topics, discuss the results of preliminary testing, and remaining development issues related to self-healing wire insulation.

  7. Development of Active Catheter,Active Guide Wire and Micro Sensor Systems

    PubMed Central

    Haga, Y.; Mineta, T.; Totsu, K.; Makishi, W.; Esashi, M.

    2001-01-01

    Summary Active catheters and active guide wires which move like a snake have been developed for catheter-based minimally invasive diagnosis and therapy. Communication and control IC chips in the active catheter reduce the number of lead wires for control. The active catheter can be not only bent but also torsioned and extended. An ultra minature fiber-optic pressure sensor; a forward-looking ultrasonic probe and a magnetic position and orientation sensor have been developed for catheters and guide wires. These moving mechanisms and several sensors which are fitted near the tip of the catheter and the guide wire will provide detailed information near the tip and enable delicate and effective catheter intervention. PMID:20663389

  8. Wire chamber

    DOEpatents

    Atac, Muzaffer

    1989-01-01

    A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

  9. Residential Wiring.

    ERIC Educational Resources Information Center

    Taylor, Mark

    The second in a series of three curriculum packages on wiring, these materials for a five-unit course were developed to prepare postsecondary students for entry-level employment in the residential wiring trade. The five units are: (1) blueprint reading and load calculations; (2) rough-in; (3) service; (4) trim out and troubleshooting; and (5) load…

  10. Point of collapse and continuation methods for large ac/dc systems

    SciTech Connect

    Canizares, C.A. ); Alvarado, F.L. )

    1993-02-01

    This paper describes the implementation of both Point of Collapse (PoC) methods and continuation methods for the computation of voltage collapse points (saddle-node bifurcations) in large ac/dc systems. A comparison of the performance of these methods is presented for real systems of up to 2,158 buses. The paper discusses computational details of the implementation of the PoC and continuation methods, and the unique challenges encountered due to the presence of high voltage direct current (HVDC) transmission, area interchange power control regulating transformers, and voltage and reactive power limits. The characteristics of a robust PoC power flow program are presented, and its application to detection and solution of voltage stability problems is demonstrated.

  11. An EMTP system level model of the PMAD DC test bed

    NASA Technical Reports Server (NTRS)

    Dravid, Narayan V.; Kacpura, Thomas J.; Tam, Kwa-Sur

    1991-01-01

    A power management and distribution direct current (PMAD DC) test bed was set up at the NASA Lewis Research Center to investigate Space Station Freedom Electric Power Systems issues. Efficiency of test bed operation significantly improves with a computer simulation model of the test bed as an adjunct tool of investigation. Such a model is developed using the Electromagnetic Transients Program (EMTP) and is available to the test bed developers and experimenters. The computer model is assembled on a modular basis. Device models of different types can be incorporated into the system model with only a few lines of code. A library of the various model types is created for this purpose. Simulation results and corresponding test bed results are presented to demonstrate model validity.

  12. An EMTP system level model of the PMAD DC test bed

    NASA Technical Reports Server (NTRS)

    Dravid, Narayan V.; Kacpura, Thomas J.; Tam, Kwa-Sur

    1991-01-01

    A power management and distribution direct current (PMAD DC) test bed was set up at the NASA Lewis Research Center to investigate Space Station Freedom Eelectric Power Systems issues. Efficiency of test bed operation significantly improves with a computer simulation model of the test bed as an adjunct tool of investigation. Such a model is developed using the Electromagnetic Transients Program (EMTP) and is available to the test bed developers and experimenters. The computer model is assembled on a modular basis. Device models of different types can be incorporated into the system model with only a few lines of code. A library of the various model types is created for this purpose. Simulation results and corresponding test bed results are presented to demonstrate model validity.

  13. McDonnell Douglas Space Systems worker checks STS-46 TSS wiring at KSC O and C

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In the Kennedy Space Center (KSC) Operations and Checkout (O and C) Building, a McDonnell Douglas Space Systems technician Hugh Beins, wearing a clean suit, inspects a complex array of wiring for the Tethered Satellite System (TSS) scheduled to fly on STS-46 aboard Atlantis, Orbiter Vehicle (OV) 104. Other technicians work on the spacelab enhanced multiplexer/demultiplexer pallet (EMP) and support struts in the background.

  14. Towards plant wires.

    PubMed

    Adamatzky, Andrew

    2014-08-01

    In experimental laboratory studies we evaluate a possibility of making electrical wires from living plants. In scoping experiments we use lettuce seedlings as a prototype model of a plant wire. We approximate an electrical potential transfer function by applying direct current voltage to the lettuce seedlings and recording output voltage. We analyse oscillation frequencies of the output potential and assess noise immunity of the plant wires. Our findings will be used in future designs of self-growing wetware circuits and devices, and integration of plant-based electronic components into future and emergent bio-hybrid systems. PMID:24928068

  15. Active semiconductor nanophotonics based on deterministic quantum wire and dot systems

    NASA Astrophysics Data System (ADS)

    Gallo, Pascal; Atlasov, K.; Calic, M.; Dwir, B.; Felici, M.; Karlsson, F.; Mohan, A.; Pelucchi, E.; Rudra, A.; Savona, V.; Surrente, A.; Tarel, G.; Zhu, Q.; Kapon, Eli

    2011-09-01

    We investigate the use of MOVPE-grown ordered nanostructures on non-planar substrates for quantum nano-photonics and quantum electrodynamics-based applications. The mastering of surface adatom fluxes on patterned GaAs substrates allows for forming nanostrucutres confining well-defined charge carrier states. An example given is the formation of quantum dot (QD) molecules tunneled-coupled by quantum wires (QWRs), in which both electron and hole states are hybridized. In addition, it is shown that the high degree of symmetry of QDs grown on patterned (111)B substrates makes them efficient entangled-photons emitters. Thanks to the optimal control over their position and emission wavelength, the fabricated nanostructures can be efficiently coupled to photonic nano-cavities. Low-threshold, optically pumped QWR laser incorporating photonic crystal (PhC) membrane cavities are demonstrated. Moreover, phononmediated coupling of QD exciton states to PhC cavities is observed. This approach should be useful for integrating more complex systems of QWRs and QDs for forming a variety of active nano-photonic structures.

  16. An Analytical Design Method for a Regenerative Braking Control System for DC-electrified Railway Systems under Light Load Conditions

    NASA Astrophysics Data System (ADS)

    Saito, Tatsuhito; Kondo, Keiichiro; Koseki, Takafumi

    A DC-electrified railway system that is fed by diode rectifiers at a substation is unable to return the electric power to an AC grid. Accordingly, the braking cars have to restrict regenerative braking power when the power consumption of the powering cars is not sufficient. However, the characteristics of a DC-electrified railway system, including the powering cars, is not known, and a mathematical model for designing a controller has not been established yet. Hence, the object of this study is to obtain the mathematical model for an analytical design method of the regenerative braking control system. In the first part of this paper, the static characteristics of this system are presented to show the position of the equilibrium point. The linearization of this system at the equilibrium point is then performed to describe the dynamic characteristics of the system. An analytical design method is then proposed on the basis of these characteristics. The proposed design method is verified by experimental tests with a 1kW class miniature model, and numerical simulations.

  17. Design of a Hybrid (Wired/Wireless) Acquisition Data System for Monitoring of Cultural Heritage Physical Parameters in Smart Cities

    PubMed Central

    García Diego, Fernando-Juan; Esteban, Borja; Merello, Paloma

    2015-01-01

    Preventive conservation represents a working method and combination of techniques which helps in determining and controlling the deterioration process of cultural heritage in order to take the necessary actions before it occurs. It is acknowledged as important, both in terms of preserving and also reducing the cost of future conservation measures. Therefore, long-term monitoring of physical parameters influencing cultural heritage is necessary. In the context of Smart Cities, monitoring of cultural heritage is of interest in order to perform future comparative studies and load information into the cloud that will be useful for the conservation of other heritage sites. In this paper the development of an economical and appropriate acquisition data system combining wired and wireless communication, as well as third party hardware for increased versatility, is presented. The device allows monitoring a complex network of points with high sampling frequency, with wired sensors in a 1-wire bus and a wireless centralized system recording data for monitoring of physical parameters, as well as the future possibility of attaching an alarm system or sending data over the Internet. This has been possible with the development of three board’s designs and more than 5000 algorithm lines. System tests have shown an adequate system operation. PMID:25815447

  18. Design of a hybrid (wired/wireless) acquisition data system for monitoring of cultural heritage physical parameters in Smart Cities.

    PubMed

    García Diego, Fernando-Juan; Esteban, Borja; Merello, Paloma

    2015-01-01

    Preventive conservation represents a working method and combination of techniques which helps in determining and controlling the deterioration process of cultural heritage in order to take the necessary actions before it occurs. It is acknowledged as important, both in terms of preserving and also reducing the cost of future conservation measures. Therefore, long-term monitoring of physical parameters influencing cultural heritage is necessary. In the context of Smart Cities, monitoring of cultural heritage is of interest in order to perform future comparative studies and load information into the cloud that will be useful for the conservation of other heritage sites. In this paper the development of an economical and appropriate acquisition data system combining wired and wireless communication, as well as third party hardware for increased versatility, is presented. The device allows monitoring a complex network of points with high sampling frequency, with wired sensors in a 1-wire bus and a wireless centralized system recording data for monitoring of physical parameters, as well as the future possibility of attaching an alarm system or sending data over the Internet. This has been possible with the development of three board's designs and more than 5000 algorithm lines. System tests have shown an adequate system operation. PMID:25815447

  19. 75 FR 36579 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-30, DC-10-30F, DC-10-30F (KC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-28

    ...We propose to adopt a new airworthiness directive (AD) for certain Model DC-10-30, DC-10-30F, DC-10-30F (KC-10A and KDC-10), DC- 10-40, DC10-40F, and MD-10-30F airplanes. This proposed AD would require doing a one-time inspection of the wire bundles to determine if wires touch the upper surface of the center upper auxiliary fuel tank, and marking the location if necessary; a one-time......

  20. Preparation and characterization of hydrogenated diamond-like carbon films in a dual DC-RF plasma system

    NASA Astrophysics Data System (ADS)

    Li, Hongxuan; Xu, Tao; Chen, Jianmin; Zhou, Huidi; Liu, Huiwen

    2003-12-01

    A dual direct current and radio frequency (DC-RF) plasma system was used to deposit hydrogenated diamond-like carbon (DLC) films from methane plasma. It has the advantages of separately controlling ion density and ion energy by RF power and DC bias, respectively, over conventional simply capacitive-coupled radio frequency plasma enhanced chemical vapour deposition system. Thus, the hydrogenated DLC films were obtained at different RF powers and DC biases, using CH4 plus Ar as the feedstock. The effects of RF power and DC bias on the structure and properties of the films were investigated by means of Fourier transformation infrared spectroscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and nano-indentation. The results were as follows: the sp3 content, hardness, and Young's modulus of the DLC films increased with increasing RF power at a constant DC bias of -200 V and reached the maximum values at an RF power of 300 W, after which they decreased with further increase of the RF power. The DC bias had a similar but greater effect on the structure and properties of the films, owing to a greater influence of the ion energy on the characteristics of the films than the ion current density. The film deposited at an RF power of 300 W and DC bias of -200 V has the most diamond-like characteristics with maximum hardness, Young's modulus, and sp3 content. Since both the ion current density and ion energy greatly affect the structure and characteristics of the DLC films, it is imperative to select proper processing parameters to obtain high quality DLC films.

  1. Investigation of the effects of laser non-linearity and RIN in direct modulation hybrid wired/wireless PON systems employing an integrated two section laser

    NASA Astrophysics Data System (ADS)

    Saljoghei, Arsalan; Browning, Colm; Smyth, Frank; Barry, Liam P.

    2015-03-01

    In this paper the transmission of OFDM based wired/wireless services for hybrid PONs using direct laser modulation is studied. To overcome the limitations imposed by direct modulation of cost effective low bandwidth laser transmitters, we make use of novel monolithically integrated Discrete Mode lasers and optical injection. The system includes a wired OFDM signal, operating at 12.5 Gb/s and three wireless signals delivering Long Term Evolution (LTE) services encoded with 16 QAM. The system's performance is evaluated for various relative power ratios of the wired/wireless signals. Additionally, the impact of Relative Intensity Noise (RIN) on such a hybrid system is studied through computer simulations.

  2. Synergetic aspects of gas-discharge: lateral patterns in dc systems with a high ohmic barrier

    NASA Astrophysics Data System (ADS)

    Purwins, H.-G.; Stollenwerk, L.

    2014-12-01

    The understanding of self-organized patterns in spatially extended nonlinear dissipative systems is one of the most challenging subjects in modern natural sciences. Such patterns are also referred to as dissipative structures. We review this phenomenon in planar low temperature dc gas-discharge devices with a high ohmic barrier. It is demonstrated that for these systems a deep qualitative understanding of dissipative structures can be obtained from the point of view of synergetics. At the same time, a major contribution can be made to the general understanding of dissipative structures. The discharge spaces of the experimentally investigated systems, to good approximation, have translational and rotational symmetry by contraction. Nevertheless, a given system may exhibit stable current density distributions and related patterns that break these symmetries. Among the experimentally observed fundamental patterns one finds homogeneous isotropic states, fronts, periodic patterns, labyrinth structures, rotating spirals, target patterns and localized filaments. In addition, structures are observed that have the former as elementary building blocks. Finally, defect structures as well as irregular patterns are common phenomena. Such structures have been detected in numerous other driven nonlinear dissipative systems, as there are ac gas-discharge devices, semiconductors, chemical solutions, electrical networks and biological systems. Therefore, from the experimental observations it is concluded that the patterns in planar low temperature dc gas-discharge devices exhibit universal behavior. From the theoretical point of view, dissipative structures of the aforementioned kind are also referred to as attractors. The possible sets of attractors are an important characteristic of the system. The number and/or qualitative nature of attractors may change when changing parameters. The related bifurcation behavior is a central issue of the synergetic approach chosen in the present article. A short review of possible theoretical approaches reveals that a theoretical description of the experimentally observed patterns is far from being satisfactory. Bearing this in mind, a qualitative model of the reaction-diffusion type is considered. Surprisingly enough, this model allows for a qualitative description of almost all fundamental patterns that have been observed experimentally. Also, so far the predictive power of this model is unmatched.

  3. Working with Systems and Thinking Systemically--Disentangling the Crossed Wires

    ERIC Educational Resources Information Center

    Fox, Mark

    2009-01-01

    This article explores two separate traditions that educational psychologists (EPs) in the UK have for working with systems. One of these is "systems work" with organisations such as schools. The other is "systemic thinking" for working with families. Over the years these two traditions, systems work and systemic thinking, have become crossed and…

  4. Working with Systems and Thinking Systemically--Disentangling the Crossed Wires

    ERIC Educational Resources Information Center

    Fox, Mark

    2009-01-01

    This article explores two separate traditions that educational psychologists (EPs) in the UK have for working with systems. One of these is "systems work" with organisations such as schools. The other is "systemic thinking" for working with families. Over the years these two traditions, systems work and systemic thinking, have become crossed and

  5. Damping of a parallel ac-dc power system using PID power system stabilizers and rectifier current regulators

    SciTech Connect

    Hsu, Y.Y.; Wang, L. )

    1988-09-01

    A novel approach is presented to improve the dynamic stability of a parallel AC-DC power system. The developed scheme employs a proportional-integral-derivative (PID) power system stabilizer (PSS) and a PID rectifier current regulator (RCR) to enhance the damping for the electromagnetical mode of the system. The parameters of the proposed PID controllers are determined using a unified approach based on modal control theory. Eigenvalue analyses are performed for the system under various operating conditions in order to compare the damping effects provided by the two different control schemes. To demonstrate the effectiveness of the proposed damping schemes under disturbance conditions simulated dynamic response tests based on a nonlinear system model are also performed.

  6. Loss characteristic analysis of high capacity HTS DC power cable considering harmonic current

    NASA Astrophysics Data System (ADS)

    Kim, J. G.; Kim, D. W.; Kim, A. R.; Park, M.; Yu, I. K.; Kim, S. H.; Sim, K. D.; Cho, J. W.

    2010-11-01

    High temperature superconducting (HTS) power cables offer an innovative transmission line that differs from conventional technologies because HTS power cables can send bulk power with extremely low loss. This paper investigates the loss characteristic of HTS DC power cable considering harmonic current caused by power electronic devices in practical power systems. We focused on the losses of HTS DC power cables and designed a model cable using YBa 2Cu 3O 7 HTS wire. The losses under DC current with harmonic components at 77 K are measured. The lower DC transport current yields more losses with the same ripple current in the unsaturated region. If DC transport current is increased within the critical current, the high frequency ripple current will have less influence on the loss. It was clearly monitored that the losses are proportional to the magnitude of the ripple current and the frequency in this study.

  7. Wire Wise.

    ERIC Educational Resources Information Center

    Swanquist, Barry

    1998-01-01

    Discusses how today's technology is encouraging schools to invest in furnishings that are adaptable to computer use and telecommunications access. Explores issues concerning modularity, wiring management, ergonomics, durability, price, and aesthetics. (GR)

  8. Lowest of AC-DC power output for electrostrictive polymers energy harvesting systems

    NASA Astrophysics Data System (ADS)

    Meddad, Mounir; Eddiai, Adil; Hajjaji, Abdelowahed; Guyomar, Daniel; Belkhiat, Saad; Boughaleb, Yahia; Chérif, Aida

    2013-11-01

    Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations.

  9. Improving the dynamic performance of a complex AC/DC system by HVDC control modifications

    SciTech Connect

    Hammad, A.E. ); Gagnon, J. ); McCallum, D. )

    1990-10-01

    The power system of Hydro-Quebec has a peak load of approximately 27 GW. The great distance between the production sites and the load centers introduces stability limitations, which is the reason why the Quebec grid cannot be economically synchronized (through ac transmission with limited capacity) with the U.S. northeastern network. Power exports are therefore dependent on the use of HVDC links of which Hydro-Quebec now possesses five, for a capacity of over 2600 MW. Such a capacity will again soon increase. At the moment, the Chateauguay scheme has the largest HVDC capacity. It transfers 1000 MW by means of two Back-to-Back converter blocks. Various automatic control systems are installed on the Chateauguay scheme owing to the fact that a single circuit of a 765 kV ac line transmits the output of both the HVDC converter stations as well as the output from Beauharnois hydro generating station. Such controls have performed satisfactorily since 1984. However, a remarkable improvement of the overall ac/dc system dynamic performance can be gained by making certain modifications in some of these HVDC system controls. This paper presents the salient features of such control modifications, currently under consideration, using the results of an investigation by digital and analogue simulations that demonstrate the achieved improvements.

  10. Iron-sulfur-based single molecular wires for enhancing charge transport in enzyme-based bioelectronic systems.

    PubMed

    Mahadevan, Aishwarya; Fernando, Teshan; Fernando, Sandun

    2016-04-15

    When redox enzymes are wired to electrodes outside a living cell (ex vivo), their ability to produce a sufficiently powerful electrical current diminishes significantly due to the thermodynamic and kinetic limitations associated with the wiring systems. Therefore, we are yet to harness the full potential of redox enzymes for the development of self-powering bioelectronics devices (such as sensors and fuel cells). Interestingly, nature uses iron-sulfur complexes ([Fe-S]), to circumvent these issues in vivo. Yet, we have not been able to utilize [Fe-S]-based chains ex vivo, primarily due to their instability in aqueous media. Here, a simple technique to attach iron (II) sulfide (FeS) to a gold surface in ethanol media and then complete the attachment of the enzyme in aqueous media is reported. Cyclic voltammetry and spectroscopy techniques confirmed the concatenation of FeS and glycerol-dehydrogenase/nicotinamide-adenine-dinucleotide (GlDH-NAD(+)) apoenzyme-coenzyme molecular wiring system on the base gold electrode. The resultant FeS-based enzyme electrode reached an open circuit voltage closer to its standard potential under a wide range of glycerol concentrations (0.001-1M). When probed under constant potential conditions, the FeS-based electrode was able to amplify current by over 10 fold as compared to electrodes fabricated with the conventional pyrroloquinoline quinone-based composite molecular wiring system. These improvements in current/voltage responses open up a wide range of possibilities for fabricating self-powering, bio-electronic devices. PMID:26657591

  11. DC CIRCUIT POWERED BY ORBITAL MOTION: MAGNETIC INTERACTIONS IN COMPACT OBJECT BINARIES AND EXOPLANETARY SYSTEMS

    SciTech Connect

    Lai Dong

    2012-09-20

    The unipolar induction DC circuit model, originally developed by Goldreich and Lynden-Bell for the Jupiter-Io system, has been applied to different types of binary systems in recent years. We show that there exists an upper limit to the magnetic interaction torque and energy dissipation rate in such a model. This arises because when the resistance of the circuit is too small, the large current flow severely twists the magnetic flux tube connecting the two binary components, leading to the breakdown of the circuit. Applying this limit, we find that in coalescing neutron star binaries, magnetic interactions produce negligible correction to the phase evolution of the gravitational waveform, even for magnetar-like field strengths. However, energy dissipation in the binary magnetosphere may still give rise to electromagnetic radiation prior to the final merger. For ultracompact white dwarf binaries, we find that unipolar induction does not provide adequate energy dissipation to explain the observed X-ray luminosities of several sources. For exoplanetary systems containing close-in Jupiters or super-Earths, the magnetic torque and energy dissipation induced by the orbital motion are negligible, except possibly during the early T Tauri phase, when the stellar magnetic field is stronger than 10{sup 3} G.

  12. Novel three-component Rieske non-heme iron oxygenase system catalyzing the N-dealkylation of chloroacetanilide herbicides in sphingomonads DC-6 and DC-2.

    PubMed

    Chen, Qing; Wang, Cheng-Hong; Deng, Shi-Kai; Wu, Ya-Dong; Li, Yi; Yao, Li; Jiang, Jian-Dong; Yan, Xin; He, Jian; Li, Shun-Peng

    2014-08-01

    Sphingomonads DC-6 and DC-2 degrade the chloroacetanilide herbicides alachlor, acetochlor, and butachlor via N-dealkylation. In this study, we report a three-component Rieske non-heme iron oxygenase (RHO) system catalyzing the N-dealkylation of these herbicides. The oxygenase component gene cndA is located in a transposable element that is highly conserved in the two strains. CndA shares 24 to 42% amino acid sequence identities with the oxygenase components of some RHOs that catalyze N- or O-demethylation. Two putative [2Fe-2S] ferredoxin genes and one glutathione reductase (GR)-type reductase gene were retrieved from the genome of each strain. These genes were not located in the immediate vicinity of cndA. The four ferredoxins share 64 to 72% amino acid sequence identities to the ferredoxin component of dicamba O-demethylase (DMO), and the two reductases share 62 to 65% amino acid sequence identities to the reductase component of DMO. cndA, the four ferredoxin genes, and the two reductases genes were expressed in Escherichia coli, and the recombinant proteins were purified using Ni-affinity chromatography. The individual components or the components in pairs displayed no activity; the enzyme mixture showed N-dealkylase activities toward alachlor, acetochlor, and butachlor only when CndA-His6 was combined with one of the four ferredoxins and one of the two reductases, suggesting that the enzyme consists of three components, a homo-oligomer oxygenase, a [2Fe-2S] ferredoxin, and a GR-type reductase, and CndA has a low specificity for the electron transport component (ETC). The N-dealkylase utilizes NADH, but not NADPH, as the electron donor. PMID:24928877

  13. Novel Three-Component Rieske Non-Heme Iron Oxygenase System Catalyzing the N-Dealkylation of Chloroacetanilide Herbicides in Sphingomonads DC-6 and DC-2

    PubMed Central

    Chen, Qing; Wang, Cheng-Hong; Deng, Shi-Kai; Wu, Ya-Dong; Li, Yi; Yao, Li; Jiang, Jian-Dong; Yan, Xin; Li, Shun-Peng

    2014-01-01

    Sphingomonads DC-6 and DC-2 degrade the chloroacetanilide herbicides alachlor, acetochlor, and butachlor via N-dealkylation. In this study, we report a three-component Rieske non-heme iron oxygenase (RHO) system catalyzing the N-dealkylation of these herbicides. The oxygenase component gene cndA is located in a transposable element that is highly conserved in the two strains. CndA shares 24 to 42% amino acid sequence identities with the oxygenase components of some RHOs that catalyze N- or O-demethylation. Two putative [2Fe-2S] ferredoxin genes and one glutathione reductase (GR)-type reductase gene were retrieved from the genome of each strain. These genes were not located in the immediate vicinity of cndA. The four ferredoxins share 64 to 72% amino acid sequence identities to the ferredoxin component of dicamba O-demethylase (DMO), and the two reductases share 62 to 65% amino acid sequence identities to the reductase component of DMO. cndA, the four ferredoxin genes, and the two reductases genes were expressed in Escherichia coli, and the recombinant proteins were purified using Ni-affinity chromatography. The individual components or the components in pairs displayed no activity; the enzyme mixture showed N-dealkylase activities toward alachlor, acetochlor, and butachlor only when CndA-His6 was combined with one of the four ferredoxins and one of the two reductases, suggesting that the enzyme consists of three components, a homo-oligomer oxygenase, a [2Fe-2S] ferredoxin, and a GR-type reductase, and CndA has a low specificity for the electron transport component (ETC). The N-dealkylase utilizes NADH, but not NADPH, as the electron donor. PMID:24928877

  14. DC Electric Field Measurement by the Double Probe System Aboard Geotail and its Simulation

    NASA Astrophysics Data System (ADS)

    Kasaba, Y.; Hayakawa, H.; Ishisaka, K.; Okada, T.; Matsuoka, A.; Mukai, T.; Okada, M.

    2005-12-01

    We summarize the characteristics of the DC electric field measurement by the double probe system, PANT and EFD-P, aboard Geotail. The accuracy and correction factors for the gain (effective length) and off-set, which depends on ambient plasma conditions, are provided. Accurate measurements of electric fields are essential for space plasma studies, for example, plasma convection, wave-particle interactions, violation of MHD approximation, etc. One typical measurement techniques is the 'Double Probe method', identical to that of a voltmeter: the potential difference between two top-hat probes [cf. Pedersen et al., 1984]. This method can measure electric fields passively and continuously in all plasma conditions. However, the accuracy of the measured electric field values is limited. The probe measurement is also subjected to the variable gain (effective length) of the probe antenna and the artificial offset of the measured values. Those depend on a) the disturbance from ambient plasma and b) the disturbance from the spacecraft and the probe itself. In this paper, we show the results of the characteristics of DC electric field measurement by the PANT probe and the EFD-P (Electric Field Detector - Probe technique) receiver aboard Geotail [Tsuruda et al., 1994], in order to evaluate the accuracy, gain, and offset controlled by ambient plasmas. We conclude that the Geotail electric field measurement by the double probe system has the accuracy 0.4 mV/m for Ex and 0.3 mV/m for Ey, after the correction of the gain and offset. In better conditions, accuracy of Ey is 0.2 mV/m. The potential accuracy would be better because those values are limited by the accuracy of the particle measurement especially in low density conditions. In practical use, the corrections by long-term variation and spacecraft potential are effective to refine the electric field data. The characteristics of long-term variation and the dependences on ambient plasma are not fully understood well, yet. Further works will be needed based on the calibrated LEP data after 1998. It will also cover the conditions rejected in this paper, i.e., low density regions, potential controlled period, electric field quasi-parallel to magnetic field, etc. The comparison with EFD-B (EFD - Beam technique) data will also be included in order to reject the ambiguity in particle observations. In addition, we are trying to establish the numerical model of the double probe system for the full-quantitative understanding of the effect of potential structure and photoelectron distributions. Those will be the basis for planned experiments, BepiColombo to Mercury, ERG to the inner magnetosphere, and the multi-spacecraft magnetospheric mission SCOPE.

  15. Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS

    NASA Astrophysics Data System (ADS)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

    2012-08-01

    The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

  16. 80 ns/45 GHz Pulsed measurement system for DC and RF characterization of high speed microwave devices

    NASA Astrophysics Data System (ADS)

    Weiß, Mario; Fregonese, Sébastien; Santorelli, Marco; Sahoo, Amit Kumar; Maneux, Cristell; Zimmer, Thomas

    2013-06-01

    This paper presents a combined pulsed I(V)-pulsed RF state-of-the-art measurement system. Isothermal DC and AC measurement data can be achieved allowing a complete characterization and exploration of the safe operating area (SOA) of advanced SiGe:C HBTs. System behavior is explained in detail and reproduced by simulation taking into account the influence of all parasitic components. Optimization steps, system verification, measurement results and accuracy issues are presented.

  17. Design and flight experience with a digital fly-by-wire control system in an F-8 airplane

    NASA Technical Reports Server (NTRS)

    Deets, D. A.; Szalai, K. J.

    1974-01-01

    A digital fly-by-wire flight control system was designed, built, and for the first time flown in an airplane. The system, which uses components from the Apollo guidance system, is installed in an F-8 airplane as the primary control system. A lunar module guidance computer is the central element in the three-axis, single-channel, multimode, digital control system. A triplex electrical analog system which provides unaugmented control of the airplane is the only backup to the digital system. Flight results showed highly successful system operation, although the trim update rate was inadequate for precise trim changes, causing minor concern. The use of a digital system to implement conventional control laws proved to be practical for flight. Logic functions coded as an integral part of the control laws were found to be advantageous. Although software verification required extensive effort, confidence in the software was achieved.

  18. Composite superconducting wires obtained by high-rate tinning in molten Bi-Pb-Sr-Ca-Cu-O system

    NASA Technical Reports Server (NTRS)

    Grosav, A. D.; Konopko, L. A.; Leporda, N. I.

    1991-01-01

    Long lengths of metal superconductor composites were prepared by passing a copper wire through the bismuth based molten oxide system at a constant speed. The key to successful composite preparation is the high pulling speed involved, which permits minimization of the severe interaction between the unbuffered metal surface and the oxide melt. Depending on the temperature of the melt and the pulling speed, a coating with different thickness and microstructure appeared. The nonannealed thick coatings contained a Bi2(Sr,Ca)2Cu1O6 phase as a major component. After relatively short time annealing at 800 C, both resistivity and initial magnetization versus temperature measurements show superconducting transitions beginning in the 110 to 115 K region. The effects of annealing and composition on obtained results are discussed. This method of manufacture led to the fabrication of wire with a copper core in a dense covering with uniform thickness of about h approximately equal to 5 to 50 microns. Composite wires with h approximately equal to 10 microns (h/d approximately equal to 0.1) sustained bending on a 15 mm radius frame without cracking during flexing.

  19. Early Oscillation Detection for DC/DC Converter Fault Diagnosis

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2011-01-01

    The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

  20. Hysteresis model of shape memory alloy wire-based laminated rubber bearing under compression and unidirectional shear loadings

    NASA Astrophysics Data System (ADS)

    Hedayati Dezfuli, F.; Shahria Alam, M.

    2015-06-01

    Smart lead rubber bearings (LRBs), in which a shape memory alloy (SMA) is used in the form of wires, are a new generation of elastomeric isolators with improved performance in terms of recentering capability and energy dissipation capacity. It is of great interest to implement SMA wire-based lead rubber bearings (SMA-LRBs) in bridges; however, currently there is no appropriate hysteresis model for accurately simulating the behavior of such isolators. A constitutive model for SMA-LRBs is proposed in this study. An LRB is equipped with a double cross configuration of SMA wires (DC-SMAW) and subjected to compression and unidirectional shear loadings. Due to the complexity of the shear behavior of the SMA-LRB, a hysteresis model is developed for the DC-SMAWs and then combined with the bilinear kinematic hardening model, which is assumed for the LRB. Comparing the hysteretic response of decoupled systems with that of the SMA-LRB shows that the high recentering capability of the DC-SMAW model with zero residual deformation could noticeably reduce the residual deformation of the LRB. The developed constitutive model for DC-SMAWs is characterized by three stiffnesses when the shear strain exceeds a starting limit at which the SMA wires are activated due to phase transformation. An important point is that the shear hysteresis of the DC-SMAW model looks different from the flag-shaped hysteresis of the SMA because of the specific arrangement of wires and its effect on the resultant forces transferred from the wires to the rubber bearing.

  1. Foundational model of structural connectivity in the nervous system with a schema for wiring diagrams, connectome, and basic plan architecture

    PubMed Central

    Swanson, Larry W.; Bota, Mihail

    2010-01-01

    The nervous system is a biological computer integrating the body's reflex and voluntary environmental interactions (behavior) with a relatively constant internal state (homeostasis)—promoting survival of the individual and species. The wiring diagram of the nervous system's structural connectivity provides an obligatory foundational model for understanding functional localization at molecular, cellular, systems, and behavioral organization levels. This paper provides a high-level, downwardly extendible, conceptual framework—like a compass and map—for describing and exploring in neuroinformatics systems (such as our Brain Architecture Knowledge Management System) the structural architecture of the nervous system's basic wiring diagram. For this, the Foundational Model of Connectivity's universe of discourse is the structural architecture of nervous system connectivity in all animals at all resolutions, and the model includes two key elements—a set of basic principles and an internally consistent set of concepts (defined vocabulary of standard terms)—arranged in an explicitly defined schema (set of relationships between concepts) allowing automatic inferences. In addition, rules and procedures for creating and modifying the foundational model are considered. Controlled vocabularies with broad community support typically are managed by standing committees of experts that create and refine boundary conditions, and a set of rules that are available on the Web. PMID:21078980

  2. Durability Evaluation of a Thin Film Sensor System With Enhanced Lead Wire Attachments on SiC/SiC Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen; Kiser, J. Douglas; Singh, Mrityunjay; Cuy, Mike; Blaha, Charles A.; Androjna, Drago

    2000-01-01

    An advanced thin film sensor system instrumented on silicon carbide (SiC) fiber reinforced SiC matrix ceramic matrix composites (SiC/SiC CMCs), was evaluated in a Mach 0.3 burner rig in order to determine its durability to monitor material/component surface temperature in harsh environments. The sensor system included thermocouples in a thin film form (5 microns thick), fine lead wires (75 microns diameter), and the bonds between these wires and the thin films. Other critical components of the overall system were the heavy, swaged lead wire cable (500 microns diameter) that contained the fine lead wires and was connected to the temperature readout, and ceramic attachments which were bonded onto the CMCs for the purpose of securing the lead wire cables, The newly developed ceramic attachment features a combination of hoops made of monolithic SiC or SiC/SiC CMC (which are joined to the test article) and high temperature ceramic cement. Two instrumented CMC panels were tested in a burner rig for a total of 40 cycles to 1150 C (2100 F). A cycle consisted of rapid heating to 1150 C (2100 F), a 5 minute hold at 1150 C (2100 F), and then cooling down to room temperature in 2 minutes. The thin film sensor systems provided repeatable temperature measurements for a maximum of 25 thermal cycles. Two of the monolithic SiC hoops debonded during the sensor fabrication process and two of the SiC/SiC CMC hoops failed during testing. The hoops filled with ceramic cement, however, showed no sign of detachment after 40 thermal cycle test. The primary failure mechanism of this sensor system was the loss of the fine lead wire-to-thin film connection, which either due to detachment of the fine lead wires from the thin film thermocouples or breakage of the fine wire.

  3. Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System

    SciTech Connect

    Stutzman, M L; Adderley, P; Brittian, J; Clark, J; Grames, J; Hansknecht, J; Myneni, G R; Poelker, M

    2007-05-01

    A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower part of the UHV range. Measured NEG pump speed is high at pressures above 5×10-11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.

  4. DC-DC powering for the CMS pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, Lutz; Fleck, Martin; Friedrichs, Marcel; Hensch, Richard; Karpinski, Waclaw; Klein, Katja; Rittich, David; Sammet, Jan; Wlochal, Michael

    2013-12-01

    The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC-DC converters close to the sensitive detector volume. This paper reviews the DC-DC powering scheme and reports on the ongoing R&D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to 24 converters. The performance of pixel modules powered by DC-DC converters is compared to conventional powering. The integration of the DC-DC powering scheme into the pixel detector is described and system design issues are reviewed.

  5. An electrochemical study of corrosion protection by primer-topcoat systems on 4130 steel with ac impedance and dc methods

    NASA Technical Reports Server (NTRS)

    Mendrek, M. J.; Higgins, R. H.; Danford, M. D.

    1988-01-01

    To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, that can be assigned in the equivalent circuit following a least-squares analysis of the data, describe changes that occur on the corroding metal surface and in the protective coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.

  6. Hy-wire and fast electric field change measurements near an isolated thunderstorm, appendix C

    NASA Technical Reports Server (NTRS)

    Holzworth, R. H.; Levine, D. M.

    1983-01-01

    Electric field measurements near an isolated thunderstorm at 6.4 km distance are presented from both a tethered balloon experiment called Hy-wire and also from ground based fast and slow electric field change systems. Simultaneous measurements were made of the electric fields during several lightning flashes at the beginning of the storm which the data clearly indicate were cloud-to-ground flashes. In addition to providing a comparison between the Hy-wire technique for measuring electric fields and more traditional methods, these data are interesting because the lightning flashes occurred prior to changes in the dc electric field, although Hy-wire measured changes in the dc field of up to 750 V/m in the direction opposite to the fair weather field a short time later. Also, the dc electric field was observed to decay back to its preflash value after each flash. The data suggest that Hy-wire was at the field reversal distance from this storm and suggest the charge realignment was taking place in the cloud with a time constant on the order of 20 seconds.

  7. No Wires.

    ERIC Educational Resources Information Center

    DeLoughry, Thomas J.

    1995-01-01

    The University of California at Santa Cruz has completed a successful test of a wireless computer network that would enable students and professors to get on line from anywhere on campus. The network, linked by radio waves, could save millions of dollars in campus wiring costs and would better meet student and faculty information needs. (MSE)

  8. Flying wires at Fermilab

    SciTech Connect

    Gannon, J.; Crawford, C.; Finley, D.; Flora, R.; Groves, T.; MacPherson, M.

    1989-03-01

    Transverse beam profile measurement systems called ''Flying Wires'' have been installed and made operational in the Fermilab Main Ring and Tevatron accelerators. These devices are used routinely to measure the emittance of both protons and antiprotons throughout the fill process, and for emittance growth measurements during stores. In the Tevatron, the individual transverse profiles of six proton and six antiproton bunches are obtained simultaneously, with a single pass of the wire through the beam. Essential features of the hardware, software, and system operation are explained in the rest of the paper. 3 refs., 4 figs.

  9. 49 CFR 236.76 - Tagging of wires and interference of wires or tags with signal apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... with signal apparatus. 236.76 Section 236.76 Transportation Other Regulations Relating to... wires and interference of wires or tags with signal apparatus. Each wire shall be tagged or otherwise so... apparatus. Inspections and Tests; All Systems...

  10. 49 CFR 236.76 - Tagging of wires and interference of wires or tags with signal apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... with signal apparatus. 236.76 Section 236.76 Transportation Other Regulations Relating to... wires and interference of wires or tags with signal apparatus. Each wire shall be tagged or otherwise so... apparatus. Inspections and Tests; All Systems...

  11. Put Your Cable Wiring to the Test.

    ERIC Educational Resources Information Center

    Day, C. William

    2001-01-01

    Discusses why schools and universities should use testing procedures in any wire bid specification for cable wiring and also know how experienced the installers are in testing and installing structured cabling systems. Key cabling terms are included. (GR)

  12. Milliwatt dc/dc Inverter

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  13. Wire-bonder-assisted integration of non-bondable SMA wires into MEMS substrates

    NASA Astrophysics Data System (ADS)

    Fischer, A. C.; Gradin, H.; Schröder, S.; Braun, S.; Stemme, G.; van der Wijngaart, W.; Niklaus, F.

    2012-05-01

    This paper reports on a novel technique for the integration of NiTi shape memory alloy wires and other non-bondable wire materials into silicon-based microelectromechanical system structures using a standard wire-bonding tool. The efficient placement and alignment functions of the wire-bonding tool are used to mechanically attach the wire to deep-etched silicon anchoring and clamping structures. This approach enables a reliable and accurate integration of wire materials that cannot be wire bonded by traditional means.

  14. Aircraft wiring program status report

    NASA Technical Reports Server (NTRS)

    Beach, Rex

    1995-01-01

    In this Naval Air Warfare Center (NAWC) Aircraft Division status report, the general and wire and cable component activities, the systems engineering activities, the aircraft wiring lead maintenance activities, the NAVAIR/NASA interface activities, and the Base Realignment and Closure (BRAC) Commission recommendations are presented.

  15. The Geostationary Operational Satellite R Series SpaceWire Based Data System Architecture

    NASA Technical Reports Server (NTRS)

    Krimchansky, Alexander; Anderson, William H.; Bearer, Craig

    2010-01-01

    The GOES-R program selected SpaceWire as the best solution to satisfy the desire for simple and flexible instrument to spacecraft command and telemetry communications. Data generated by GOES-R instruments is critical for meteorological forecasting, public safety, space weather, and other key applications. In addition, GOES-R instrument data is provided to ground stations on a 24/7 basis. GOES-R requires data errors be detected and corrected from origin to final destination. This paper describes GOES-R developed strategy to satisfy this requirement

  16. Universality versus material dependence of fluctuation forces between metallic wires

    SciTech Connect

    Noruzifar, E.; Emig, T.; Zandi, R.

    2011-10-15

    We calculate the Casimir interaction between two parallel wires and between a wire and a metal plate. The dielectric properties of the objects are described by the plasma, Drude, and perfect metal models. We find that at asymptotically large separation interactions involving plasma, wires and/or plates are independent of the material properties but depend on the dc conductivity {sigma} for Drude wires. Counterintuitively, at intermediate separations the interaction involving Drude wires can become independent of {sigma}. At smaller separations, we compute the interaction numerically and observe an approach to the proximity approximation.

  17. Hybrid CATV/MMW/BB lightwave transmission system based on fiber-wired/fiber-wireless/fiber-VLLC integrations.

    PubMed

    Li, Chung-Yi; Lu, Hai-Han; Lu, Ting-Chieh; Chu, Chien-An; Chen, Bo-Rui; Lin, Chun-Yu; Peng, Peng-Chun

    2015-12-14

    A hybrid lightwave transmission system for cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission based on fiber-wired/fiber-wireless/fiber-visible laser light communication (VLLC) integrations is proposed and demonstrated. For down-link transmission, the light is intensity-modulated with 50-550 MHz CATV signal and optically promoted from 25 GHz radio frequency (RF) signal to 10 Gbps/50 GHz and 20 Gbps/100 GHz MMW data signals based on fiber-wired and fiber-wireless integrations. Good performances of carrier-to-noise ratio (CNR), composite second-order (CSO), composite triple-beat (CTB), and bit error rate (BER) are obtained over a 40-km single-mode fiber (SMF) and a 10-m RF wireless transport. For up-link transmission, the light is successfully intensity-remodulated with 5-Gbps BB data stream based on fiber-VLLC integration. Good BER performance is achieved over a 40-km SMF and a 10-m free-space VLLC transport. Such a hybrid CATV/MMW/BB lightwave transmission system is an attractive alternative, it gives the benefits of a communication link for broader bandwidth and higher transmission rate. PMID:26698972

  18. Design and Development of a D.C. Magnetron Sputtering System for Thin Film and Multilayer Deposition

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Debarati; Biswas, A.; Bhushan, K. G.; Swain, M.; Basu, S.

    2011-07-01

    A D.C. magnetron sputtering system has been designed and developed for the deposition of thin films and multilayers. The aim of generating such layered structures is the creation of materials with novel properties e.g. neutron mirrors. For this purpose the design of the system had some special requirements. After installation and optimization, the deposition system was successfully used to deposit films of Cu, Al and Ni on Si substrates (only the latter is being reported here), which were analyzed by x-ray reflectivity and time-of-flight secondary ion mass spectrometry.

  19. Chemical Evolution in Upper Tropospheric Convective Outflow: Case Study of a Mesoscale Convective System During DC3 (Invited)

    NASA Astrophysics Data System (ADS)

    Olson, J. R.; Crawford, J. H.; Diskin, G. S.; Sachse, G. W.; Blake, D. R.; Blake, N. J.; Brune, W. H.; Zhang, L.; Ren, X.; Mao, J.; Cohen, R. C.; Nault, B.; Dibb, J. E.; Cantrell, C. A.; Fried, A.; Richter, D.; Weibring, P.; Apel, E. C.; Flocke, F. M.; Hall, S. R.; Hornbrook, R. S.; Ullmann, K.; Weinheimer, A. J.; Hanisco, T. F.; Ryerson, T. B.; Crounse, J.; St Clair, J. M.; Wennberg, P. O.; Wisthaler, A.; Mikoviny, T.

    2013-12-01

    The jointly sponsored NSF/NASA/NOAA Deep Convective Clouds and Chemistry Project (DC3) took place during summer of 2012 to investigate the impact of deep convection over central North America on upper tropospheric composition and chemistry. On June 21, coordinated successive flights by the DC8 and GV aircraft successfully captured photochemical aging within and along the outflow of a decaying Mesoscale Convective System. Increases in ozone, HNO3, and PANs, accompanied by decreases in CH2O, NOx, VOCs and OVOCs are qualitatively consistent with persistent photochemistry for up to 12 daylight hours following the convective perturbations. The extended chemical processing is examined in detail using this rich data set and predictions of chemical evolution from the NASA LaRC Lagrangian photochemical box model, constrained with time varying observations of precursors along segments of the outflow.

  20. Transcriptional regulation of cardiac conduction system development: 2004 FASEB cardiac conduction system minimeeting, Washington, DC.

    PubMed

    Harris, Brett S; Jay, Patrick Y; Rackley, Mary S; Izumo, Seigo; O'brien, Terrence X; Gourdie, Robert G

    2004-10-01

    The development of the complex network of specialized cells that form the atrioventricular conduction system (AVCS) during cardiac morphogenesis occurs by progressive recruitment within a multipotent cardiomyogenic lineage. Understanding the molecular control of this developmental process has been the focus of recent research. Transcription factors representative of multiple subfamilies have been identified and include members of zinc-finger subfamilies (GATA4, GATA6 HF-1b), skeletal muscle transcription factors (MyoD), T-box genes (Tbx5), and also homeodomain transcription factors (Msx2 and Nkx2.5). Mutations in some of these transcription factors cause congenital heart disease and are associated with cardiac abnormalities, including deficits within the AVCS. Mouse models that closely phenocopy known human heart disease provide powerful tools for the study of molecular effectors of AVCS development. Indeed, investigations of the Nkx2.5 haploinsufficient mouse have shown that peripheral Purkinje fibers are significantly underrepresented. This piece of data corroborates our previous work showing in chick, mouse, and humans that Nkx2.5 is elevated in the differentiating AVCS relative to adjacent working ventricular myocardial tissues. Using the chick embryo as a model, we show that this elevation of Nkx2.5 is transient in the network of conduction cells comprising the peripheral Purkinje fiber system. Functional studies using defective adenoviral constructs, which disrupt the normal variation in level of this gene, result in perturbations of Purkinje fiber phenotype. Thus, the precise spatiotemporal regulation of Nkx2.5 levels during development may be required for the progressive emergence of gene expression patterns specific to differentiated Purkinje fiber cells. PMID:15368344

  1. Radiation effects on DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Zhang, Dexin; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2000-01-01

    DC-DC switching converters are circuits that can be used to convert a DC voltage of one value to another by switching action. They are increasing being used in space systems. Most of the popular DC-DC switching converters utilize power MOSFETs. However power MOSFETs, when subjected to radiation, are susceptible to degradation of device characteristics or catastrophic failure. This work focuses on the effects of total ionizing dose on converter performance. Four fundamental switching converters (buck converter, buck-boost converter, cuk converter, and flyback converter) were built using Harris IRF250 power MOSFETs. These converters were designed for converting an input of 60 volts to an output of about 12 volts with a switching frequency of 100 kHz. The four converters were irradiated with a Co-60 gamma source at dose rate of 217 rad/min. The performances of the four converters were examined during the exposure to the radiation. The experimental results show that the output voltage of the converters increases as total dose increases. However, the increases of the output voltage were different for the four different converters, with the buck converter and cuk converter the highest and the flyback converter the lowest. We observed significant increases in output voltage for cuk converter at a total dose of 24 krad (si).

  2. Precision wire feeder for small diameter wire

    DOEpatents

    Brandon, Eldon D.; Hooper, Frederick M.; Reichenbach, Marvin L.

    1992-01-01

    A device for feeding small diameter wire having a diameter less than 0.04 mm (16 mil) to a welding station includes a driving wheel for controllably applying a non-deforming driving force to the wire to move the free end of the wire towards the welding station; and a tension device such as a torque motor for constantly applying a reverse force to the wire in opposition to the driving force to keep the wire taut.

  3. Precision wire feeder for small diameter wire

    DOEpatents

    Brandon, E.D.; Hooper, F.M.; Reichenbach, M.L.

    1992-08-11

    A device for feeding small diameter wire having a diameter less than 0.04 mm (16 mil) to a welding station includes a driving wheel for controllably applying a non-deforming driving force to the wire to move the free end of the wire towards the welding station; and a tension device such as a torque motor for constantly applying a reverse force to the wire in opposition to the driving force to keep the wire taut. 1 figure.

  4. Simplified dc to dc converter

    NASA Technical Reports Server (NTRS)

    Gruber, R. P. (Inventor)

    1984-01-01

    A dc to dc converter which can start with a shorted output and which regulates output voltage and current is described. Voltage controlled switches directed current through the primary of a transformer the secondary of which includes virtual reactance. The switching frequency of the switches is appropriately varied to increase the voltage drop across the virtual reactance in the secondary winding to which there is connected a low impedance load. A starting circuit suitable for voltage switching devices is provided.

  5. 75 FR 44988 - Wire Decking From China; Determinations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-30

    ... Commission, Washington, DC, and by publishing the notice in the Federal Register on January 28, 2010 (75 FR... COMMISSION Wire Decking From China; Determinations On the basis of the record \\1\\ developed in the subject... of wire decking from China, provided for in subheadings 9403.90.80, 7217.10, 7217.20, 7326.20,...

  6. NEMA wire and cable standards development programs

    NASA Technical Reports Server (NTRS)

    Baird, Robert W.

    1994-01-01

    The National Electrical Manufacturers Association (NEMA) is the nation's largest trade association for manufacturers of electrical equipment. Its member companies produce components, end-use equipment and systems for the generation, transmission, distribution, control and use of electricity. The wire and cable division is presented in 6 sections: building wire and cable, fabricated conductors, flexible cords, high performance wire and cable, magnet wire, and power and control cable. Participating companies are listed.

  7. Hierarchical Assembly of a Dual-responsive Macroscopic Insulated Molecular Wire Bundle in a Gradient System

    NASA Astrophysics Data System (ADS)

    Sheng, Yujie; Chen, Qibin; Yao, Junyao; Wang, Ying; Liu, Honglai

    2015-01-01

    Here, we report the hierarchical self-assembly of a cationic gemini amphiphile, Azo 1, in a composition gradient solution generated using solvent evaporation. As the gradient solution is formed, Azo 1 forms nanorods in the lower region of the solution. Depending on solvent composition, these nanorods can further develop into nanofibres, which can then intertwine to form double helices and other types of nanohelices in the upper region of the solution. Finally, a macroscopic wire bundle is formed via the fusion of nanohelices; this ribbon-like bundle exhibits elasticity and linear ohmic resistance properties. More intriguingly, this bundle exhibits photoresponsive properties that affect its deformation and conductivity, as well as a rapid electroresponse that affects its conductivity, indicating that it is feasible to control the charge pathway.

  8. Hierarchical Assembly of a Dual-responsive Macroscopic Insulated Molecular Wire Bundle in a Gradient System

    PubMed Central

    Sheng, Yujie; Chen, Qibin; Yao, Junyao; Wang, Ying; Liu, Honglai

    2015-01-01

    Here, we report the hierarchical self-assembly of a cationic gemini amphiphile, Azo 1, in a composition gradient solution generated using solvent evaporation. As the gradient solution is formed, Azo 1 forms nanorods in the lower region of the solution. Depending on solvent composition, these nanorods can further develop into nanofibres, which can then intertwine to form double helices and other types of nanohelices in the upper region of the solution. Finally, a macroscopic wire bundle is formed via the fusion of nanohelices; this ribbon-like bundle exhibits elasticity and linear ohmic resistance properties. More intriguingly, this bundle exhibits photoresponsive properties that affect its deformation and conductivity, as well as a rapid electroresponse that affects its conductivity, indicating that it is feasible to control the charge pathway. PMID:25588881

  9. Novel Radiopaque UHMWPE Sublaminar Wires in a Growth-Guidance System for the Treatment of Early Onset Scoliosis: Feasibility in a Large Animal Study.

    PubMed

    Bogie, R; Roth, Ak; Faber, S; de Jong, Jja; Welting, Tjm; Willems, Pc; Arts, Jj; van Rhijn, Lw

    2014-09-29

    Study Design. In vivo analysis in an ovine model.Objective. To evaluate the feasibility of radiopaque UHMWPE sublaminar wires in a growth-guidance spinal system by assessing stability, biocompatibility and growth potential.Summary of Background Data. Several growth-guidance systems have been developed for the treatment of early onset scoliosis (EOS). The use of gliding pedicle screws and metal sublaminar wires during these procedures can cause metal-on-metal debris formation and neurological deficits. Novel radiopaque UHMWPE wires are introduced to safely facilitate longitudinal growth and provide stability in a growth-guidance system for EOS.Methods. Twelve immature sheep received posterior segmental spinal instrumentation; pedicle screws were inserted at L5 and radiopaque UHWMPE (bismuth trioxide) wires were passed sublaminarly at each level between L3 and T11 and fixed to dual cobalt-chromiun rods. Four age-matched, unoperated animals were evaluated to serve as a control group. Radiographs were taken to measure growth of the instrumented segment. After 24 weeks, the animals were sacrificed and the spines were harvested for histological evaluation and high resolution peripheral quantitative computed tomography (HR-pQCT) analysis.Results. No neurological deficits occurred and all instrumentation remained stable. One animal died from an unknown cause. Substantial growth occurred in the instrumented segments (L5-T11) in the intervention group (27± 2 mm), which was not significantly different to the control group, (30 ± 4mm, p = 0.42). HR-pQCT analysis clearly showed safe routing and fixation of the UHMWPE wires and instrumentation. Despite the noted growth, ectopic bone formation with the formation of bony bridges was observed in all animals. Histology revealed no evidence of chronic inflammation or wear debris.Conclusions. This study shows the first results of radiopaque UHMWPE sublaminar wires as part of a growth guidance spinal system. UHMWPE sublaminar wires facilitated near-normal longitudinal spinal growth. All instrumentation remained stable throughout follow-up; no wire breakage or loosening occurred and no adverse local tissue response to these wires was observed. PMID:25271492

  10. 46 CFR 129.340 - Cable and wiring.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Cable and wiring. 129.340 Section 129.340 Shipping COAST... Power Sources and Distribution Systems § 129.340 Cable and wiring. (a) If individual wires, rather than cables, are used in systems operating at a potential of greater than 50 volts, the wire and...

  11. 46 CFR 129.340 - Cable and wiring.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Cable and wiring. 129.340 Section 129.340 Shipping COAST... Power Sources and Distribution Systems § 129.340 Cable and wiring. (a) If individual wires, rather than cables, are used in systems operating at a potential of greater than 50 volts, the wire and...

  12. 46 CFR 120.340 - Cable and wiring requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Cable and wiring requirements. 120.340 Section 120.340... INSTALLATION Power Sources and Distribution Systems § 120.340 Cable and wiring requirements. (a) If individual wires, rather than cables, are used in systems greater than 50 volts, the wire must be in conduit....

  13. 46 CFR 129.340 - Cable and wiring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Cable and wiring. 129.340 Section 129.340 Shipping COAST... Power Sources and Distribution Systems § 129.340 Cable and wiring. (a) If individual wires, rather than cables, are used in systems operating at a potential of greater than 50 volts, the wire and...

  14. 46 CFR 120.340 - Cable and wiring requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Cable and wiring requirements. 120.340 Section 120.340... INSTALLATION Power Sources and Distribution Systems § 120.340 Cable and wiring requirements. (a) If individual wires, rather than cables, are used in systems greater than 50 volts, the wire must be in conduit....

  15. 46 CFR 120.340 - Cable and wiring requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Cable and wiring requirements. 120.340 Section 120.340... INSTALLATION Power Sources and Distribution Systems § 120.340 Cable and wiring requirements. (a) If individual wires, rather than cables, are used in systems greater than 50 volts, the wire must be in conduit....

  16. A system to study the stability of the wires of multiwire proportional chambers exposed to a 10 G time variable force field

    NASA Astrophysics Data System (ADS)

    Ceci, N.; Raino, A.; Spinelli, P.; Stagno, V.

    1991-08-01

    Results are presented of a system to test the behavior of the wires of multiwire proportional chambers (MWPCs) exposed for 10 min to a uniform force field of about 10 G strength and variable in time in the frequency range 0-2000 Hz. This acceleration will be present when the chambers, mounted inside a cosmic ray spectrometer, are launched by the Space Shuttle toward the NASA Space Station Freedom. These conditions were reproduced in the laboratory by an electron device, and it was found that, after repeated cycles of this treatment, the wire performance remained unchanged. This system can also be used to control the tension of the wires of a MWPC during its normal testing procedure.

  17. DC to DC battery charger

    SciTech Connect

    Carr, F.L.; Terrill, L.R.

    1987-01-20

    A DC to DC battery charger is described for a vehicle comprising: adapter plug means for making electrical connections to a first battery through a cigarette lighter socket in the vehicle; means of making electrical connections to a second battery to be charged; a DC to AC converter and an AC to DC rectifier for elevating the voltage from the first battery to a voltage above that of the second battery; integrated circuit means for generating a pulse width modulated current as a function for the charged condition of the second battery; transistor switch means supplied with the pulse width modulated current for developing a charging voltage; a choke coil and a capacitor serially connected to the transistor switch means; and a diode connected across the choke coil and the capacitor whereby the capacitor is charged during pulses of current from the transistor switch means through the choke coil. The choke coil reverses polarity at the termination of the pulses of current and continues to charge the battery through the diode. The DC rectified voltage is controlled by the integrated circuit means for regulating current through the choke coil.

  18. Design research on the conductor of 10 kA class HTS DC power cable

    NASA Astrophysics Data System (ADS)

    Zhang, Dong; Dai, Shaotao; Zhang, Fengyuan; Huang, Tianbin; Wang, Yinshun; Lin, Yubao; Teng, Yuping; Zhang, Guomin; Xiao, Liye; Lin, Liangzhen

    2012-12-01

    High temperature superconducting (HTS) DC power cable shows a wide application prospect in the field of power transmission for its nearly lossless and rather high capacity. A 360 m/10 kA HTS DC power cable system, which connects the rectifier output of a substation with the bus bar of an electrolytic aluminium cell, will be put into operation at Henan Zhongfu Industrial Co., Ltd. As one of the items in this project, a 5 m/10 kA HTS DC power cable was developed, which is used to investigate the conductor design, fabrication, current-carrying capacity and stability of the 360 m/10 kA HTS power cable. The HTS DC power cable core consists of five conductor layers wound with spliced Bi-2223 wires with the length of 600 m. The cable core has five layers and 23 conductors in each layer with the outer diameter of 45.42 mm. The superconducting power cable is fabricated and tested. The critical current is about 14.3 kA at 77 K. The superconducting power cable is charged to 10 kA with rate of 10 A/s and operates at steady-state for 30 min. In this paper, the 10 kA HTS DC power cable design, fabrication and test are presented. The experimental research of the performance of spliced superconducting wire and charging, steady-state operating performance of the cable was carried out.

  19. Model Predictive Control techniques with application to photovoltaic, DC Microgrid, and a multi-sourced hybrid energy system

    NASA Astrophysics Data System (ADS)

    Shadmand, Mohammad Bagher

    Renewable energy sources continue to gain popularity. However, two major limitations exist that prevent widespread adoption: availability and variability of the electricity generated and the cost of the equipment. The focus of this dissertation is Model Predictive Control (MPC) for optimal sized photovoltaic (PV), DC Microgrid, and multi-sourced hybrid energy systems. The main considered applications are: maximum power point tracking (MPPT) by MPC, droop predictive control of DC microgrid, MPC of grid-interaction inverter, MPC of a capacitor-less VAR compensator based on matrix converter (MC). This dissertation firstly investigates a multi-objective optimization technique for a hybrid distribution system. The variability of a high-penetration PV scenario is also studied when incorporated into the microgrid concept. Emerging (PV) technologies have enabled the creation of contoured and conformal PV surfaces; the effect of using non-planar PV modules on variability is also analyzed. The proposed predictive control to achieve maximum power point for isolated and grid-tied PV systems speeds up the control loop since it predicts error before the switching signal is applied to the converter. The low conversion efficiency of PV cells means we want to ensure always operating at maximum possible power point to make the system economical. Thus the proposed MPPT technique can capture more energy compared to the conventional MPPT techniques from same amount of installed solar panel. Because of the MPPT requirement, the output voltage of the converter may vary. Therefore a droop control is needed to feed multiple arrays of photovoltaic systems to a DC bus in microgrid community. Development of a droop control technique by means of predictive control is another application of this dissertation. Reactive power, denoted as Volt Ampere Reactive (VAR), has several undesirable consequences on AC power system network such as reduction in power transfer capability and increase in transmission loss if not controlled appropriately. Inductive loads which operate with lagging power factor consume VARs, thus load compensation techniques by capacitor bank employment locally supply VARs needed by the load. Capacitors are highly unreliable components due to their failure modes and aging inherent. Approximately 60% of power electronic devices failure such as voltage-source inverter based static synchronous compensator (STATCOM) is due to the use of aluminum electrolytic DC capacitors. Therefore, a capacitor-less VAR compensation is desired. This dissertation also investigates a STATCOM capacitor-less reactive power compensation that uses only inductors combined with predictive controlled matrix converter.

  20. Photovoltaic powered 20-hp DC/AC irrigation system and a 3-kW nitrogen generator

    SciTech Connect

    Hopkinson, R.F.

    1980-01-01

    A 25-kWp photovoltaic power system has been providing power for irrigation and crop drying since July 1977 at an agricultural field station of the University of Nebraska, located at Mead, Nebraska. The system was designed and built by Massachusetts Institute of Technology's Lincoln Laboratory under US Department of Energy sponsorship and is being operated jointly by the university and MIT Lincoln Laboratory. The system consists of a 25-kWp PV array, a battery subsystem, a power dump, an inverter, a controller and a data acquisition system. This photovoltaic power system has been used as a test facility in order to test and evaluate a variety of PV-related agricultural applications, including irrigation, crop drying and fertilizer manufacturing. Two interesting applications presently under evaluation are a 20-hp DC/AC-powered irrigation system and an on-site nitrogen fertilizer production unit.

  1. An Adaptive Coordinated Control for an Offshore Wind Farm Connected VSC Based Multi-Terminal DC Transmission System

    NASA Astrophysics Data System (ADS)

    Kumar, M. Ajay; Srikanth, N. V.

    2014-11-01

    The voltage source converter (VSC) based multiterminal high voltage direct current (MTDC) transmission system is an interesting technical option to integrate offshore wind farms with the onshore grid due to its unique performance characteristics and reduced power loss via extruded DC cables. In order to enhance the reliability and stability of the MTDC system, an adaptive neuro fuzzy inference system (ANFIS) based coordinated control design has been addressed in this paper. A four terminal VSC-MTDC system which consists of an offshore wind farm and oil platform is implemented in MATLAB/ SimPowerSystems software. The proposed model is tested under different fault scenarios along with the converter outage and simulation results show that the novel coordinated control design has great dynamic stabilities and also the VSC-MTDC system can supply AC voltage of good quality to offshore loads during the disturbances.

  2. Composite superconducting wires obtained by high-rate tinning in molten Bi-Pb-Sr-Ca-Cu-O system

    NASA Technical Reports Server (NTRS)

    Grozav, A. D.; Konopko, L. A.; Leporda, N. I.

    1990-01-01

    The preparation of high-T(sub c) superconducting long composite wires by short-time tinning of the metal wires in a molten Bi-Pb-Sr-Ca-Cu-O compound is discussed. The application of this method to the high-T(sub c) materials is tested, possibly for the first time. The initial materials used for this experiment were ceramic samples with nominal composition Bi(1.5)Pb(0.5)Sr2Ca2Cu3O(x) and T(sub c) = 80 K prepared by the ordinary solid-state reaction, and industrial copper wires from 100 to 400 microns in diameter and from 0.5 to 1 m long. The continuously moving wires were let through a small molten zone (approximately 100 cubic mm). The Bi-based high-T(sub c) ceramics in a molten state is a viscous liquid and it has a strongly pronounced ability to spread on metal wire surfaces. The maximum draw rate of the Cu-wire, at which a dense covering is still possible, corresponds to the time of direct contact of wire surfaces and liquid ceramics for less than 0.1 s. A high-rate draw of the wire permits a decrease in the reaction of the oxide melt and Cu-wire. This method of manufacture led to the fabrication of wire with a copper core in a dense covering with uniform thickness of about h approximately equal to 5 to 50 microns. Composite wires with h approximately equal to 10 microns (h/d approximately equal to 0.1) sustained bending on a 15 mm radius frame without cracking during flexing.

  3. Electrically heated wire-loop, in-torch vaporization sample introduction system for inductively coupled plasma atomic emission spectrometry with photodiode array detection

    NASA Astrophysics Data System (ADS)

    Karanassios, Vassili; Bateman, Kevin P.; Spiers, Graeme A.

    1994-08-01

    A new sample introduction system that can be used for the analysis of microliter volumes of liquids by inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The system consists of an electrically heated W wire-loop which is attached to a thermocouple ceramic insulator. Ceramic and wire-loop are inserted manually into the central tube of a modified ICP torch, with the top of the wire-loop positioned about 10 cm below the plasma. An inexpensive variac, which plugs into a wall socket, is used as a power supply. This in-torch vaporization (ITV) sample introduction system was characterized using an ICP optical emission spectrometer with a photodiode array detector. In this pilot study aimed at testing the validity of the approach, spectral interference effects arising from W emission lines are documented for Be, Cu, Mn, Sc, Sr, V, Y and Zn and preliminary analytical performance characteristics using an unoptimized wire-loop/torch design are presented. Calibration curves were linear for over three orders of magnitude for Sr, Y and Be; the non-linear calibration curves obtained for Cu were attributed to contamination from the power transfer cables, for Mg to contamination from the ceramic and for Ca to airborne particles adhering to the wire-loop. As well, Au-coated W wire-loops proved to be sensitive to Hg 0-vapor in air. Precision varied between 1.9 and 4.5% (10 μl injection of single element standards) and, estimated absolute detection limits were (in pg) Zn (710), V (20), Mn (10), Y (10), Sc (9), Be (1) and Sr (0.4).

  4. Fabrication of tungsten wire needles

    SciTech Connect

    Roder, A.

    1983-02-01

    Fine point needles for field emissoin are conventionally produced by electrolytically or chemically etching tungsten wire. Points formed in this manner have a typical tip radius of about 0.5 microns and a cone angle of some 30 degrees. The construction of needle matrix detector chambers has created a need for tungsten needles whose specifications are: 20 mil tungsten wire, 1.5 inch total length, 3 mm-long taper (resulting in a cone angle of about 5 degrees), and 25 micron-radius point (similar to that found on sewing needles). In the process described here for producing such needles, tungsten wire, immersed in a NaOH solution and in the presence of an electrode, is connected first to an ac voltage and then to a dc supply, to form a taper and a point on the end of the wire immersed in the solution. The process parameters described here are for needles that will meet the above specifications. Possible variations will be discussed under each approprite heading.

  5. NASA wiring for space applications program

    NASA Technical Reports Server (NTRS)

    Schulze, Norman

    1995-01-01

    An overview of the NASA Wiring for Space Applications Program and its relationship to NASA's space technology enterprise is given in viewgraph format. The mission of the space technology enterprise is to pioneer, with industry, the development and use of space technology to secure national economic competitiveness, promote industrial growth, and to support space missions. The objectives of the NASA Wiring for Space Applications Program is to improve the safety, performance, and reliability of wiring systems for space applications and to develop improved wiring technologies for NASA flight programs and commercial applications. Wiring system failures in space and commercial applications have shown the need for arc track resistant wiring constructions. A matrix of tests performed versus wiring constructions is presented. Preliminary data indicate the performance of the Tensolite and Filotex hybrid constructions are the best of the various candidates.

  6. DC to DC power converters and methods of controlling the same

    SciTech Connect

    Steigerwald, Robert Louis; Elasser, Ahmed; Sabate, Juan Antonio; Todorovic, Maja Harfman; Agamy, Mohammed

    2012-12-11

    A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

  7. COBRA-STAR, a five frame point-projection x-ray imaging system for 1 MA scale wire-array Z pinches

    SciTech Connect

    Douglass, J. D.; Hammer, D. A.

    2008-03-15

    A new imaging system for 1 MA scale wire-array Z-pinch experiments that produces up to five high-resolution x-ray images per experimental pulse has been developed. Calibrated areal density measurements of the Z-pinch plasma can be obtained from each pulse. The system substitutes five molybdenum (Mo) X pinches for the normal copper return-current conductors to provide point sources of x-rays for point-projection radiography. Each backlighting X pinch consists of four Mo wires, the x-ray burst timing of which was controlled by varying the wire diameter (mass) from 10.2 to 30 {mu}m in the five X pinches. Typical images have a 16x8 mm{sup 2} field of view at the wire array and a magnification of about 6.5:1 on the x-ray-sensitive film. Titanium (Ti) filters in front of the films transmit continuum radiation in the spectral range of 3-5 keV. Inclusion on the Ti of a step wedge having known thickness increments of the same material as the wires enables the calibrated areal density measurements to be made of the exploding wire plasmas. Here, we used tungsten (W) step wedges with step thicknesses ranging from 0.015 to 1.1 {mu}m to obtain accurate ({+-}10%) areal density measurements of W plasmas from the spatial profile of film exposure. When imaging arrays that produce intense radiation pulses, a plastic monofilament ''quencher'' is placed on axis to avoid film saturation. Images have subnanosecond temporal resolution and about 7 {mu}m spatial resolution.

  8. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    DOEpatents

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  9. 47 CFR 68.215 - Installation of other than “fully protected” system premises wiring that serves more than four...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Installation of other than âfully protectedâ system premises wiring that serves more than four subscriber access lines. 68.215 Section 68.215 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) CONNECTION OF TERMINAL EQUIPMENT TO THE...

  10. 47 CFR 68.215 - Installation of other than “fully protected” system premises wiring that serves more than four...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Installation of other than âfully protectedâ system premises wiring that serves more than four subscriber access lines. 68.215 Section 68.215 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) CONNECTION OF TERMINAL EQUIPMENT TO THE...

  11. Improved Method of Locating Defects in Wiring Insulation

    NASA Technical Reports Server (NTRS)

    Greulich, Owen R.

    2004-01-01

    An improved method of locating small breaches in insulation on electrical wires combines aspects of the prior dielectric withstand voltage (DWV) and time-domain reflectometry (TDR) methods. The method was invented to satisfy a need for reliably and quickly locating insulation defects in spacecraft, aircraft, ships, and other complex systems that contain large amounts of wiring, much of it enclosed in structures that make it difficult to inspect. In the DWV method, one applies a predetermined potential (usually 1.5 kV DC) to the wiring and notes whether the voltage causes any arcing between the wiring and ground. The DWV method does not provide an indication of the location of the defect (unless, in an exceptional case, the arc happens to be visible). In addition, if there is no electrically conductive component at ground potential within about 0.010 in. (approximately equal to 0.254 mm) of the wire at the location of an insulation defect, then the DWV method does not provide an indication of the defect. Moreover, one does not have the option to raise the potential in an effort to increase the detectability of such a defect because doing so can harm previously undamaged insulation. In the TDR method as practiced heretofore, one applies a pulse of electricity having an amplitude of less than 25 V to a wire and measures the round-trip travel time for the reflection of the pulse from a defect. The distance along the wire from the point of application of the pulse to the defect is then calculated as the product of half the round-trip travel time and the characteristic speed of a propagation of an electromagnetic signal in the wire. While the TDR method as practiced heretofore can be used to locate a short or open circuit, it does not ordinarily enable one to locate a small breach in insulation because the pulse voltage is too low to cause arcing and thus too low to induce an impedance discontinuity large enough to generate a measurable reflection. The present improved method overcomes the weaknesses of both the prior DWV and the prior TDR method.

  12. DC-SIGN activation mediates the differential effects of SAP and CRP on the innate immune system and inhibits fibrosis in mice

    PubMed Central

    Cox, Nehemiah; Pilling, Darrell; Gomer, Richard H.

    2015-01-01

    Fibrosis is caused by scar tissue formation in internal organs and is associated with 45% of deaths in the United States. Two closely related human serum proteins, serum amyloid P (SAP) and C-reactive protein (CRP), strongly affect fibrosis. In multiple animal models, and in Phase 1 and Phase 2 clinical trials, SAP affects several aspects of the innate immune system to reduce fibrosis, whereas CRP appears to potentiate fibrosis. However, SAP and CRP bind the same Fcγ receptors (FcγR) with similar affinities, and why SAP and CRP have opposing effects is unknown. Here, we report that SAP but not CRP binds the receptor DC-SIGN (SIGN-R1) to affect the innate immune system, and that FcγR are not necessary for SAP function. A polycyclic aminothiazole DC-SIGN ligand and anti–DC-SIGN antibodies mimic SAP effects in vitro. In mice, the aminothiazole reduces neutrophil accumulation in a model of acute lung inflammation and, at 0.001 mg/kg, alleviates pulmonary fibrosis by increasing levels of the immunosuppressant IL-10. DC-SIGN (SIGN-R1) is present on mouse lung epithelial cells, and SAP and the aminothiazole potentiate IL-10 production from these cells. Our data suggest that SAP activates DC-SIGN to regulate the innate immune system differently from CRP, and that DC-SIGN is a target for antifibrotics. PMID:26106150

  13. /ital In/ /ital situ/ dc oxygen-discharge cleaning system for optical elements

    SciTech Connect

    Koide, T.; Shidara, T.; Tanaka, K.; Yagishita, A.; Sato, S.

    1989-07-01

    /ital In/ /ital situ/ dc oxygen-discharge cleaning arrangements have been developed at the Photon Factory for the removal of carbon contamination from optical surfaces. A high cleaning rate could be achieved by producing an oxygen plasma close to the optical elements with special care taken to avoid any harmful effects from the discharge; contaminant carbon was completely removed within a few hours, at most. This short exposure time and the use of dry oxygen gas resulted in a restoration of the original ultrahigh vacuum without a bakeout. Results with a Seya-Namioka beamline for gas-phase experiments showed a flux enhancement amounting to a factor of 50, and results with a grasshopper beamline showed a nearly complete recovery of the light intensity, even at the carbon /ital K/ edge.

  14. In situ dc oxygen-discharge cleaning system for optical elements

    NASA Astrophysics Data System (ADS)

    Koide, Tsuneharu; Shidara, Tetsuo; Tanaka, Kenichiro; Yagishita, Akira; Sato, Shigeru

    1989-07-01

    In situ dc oxygen-discharge cleaning arrangements have been developed at the Photon Factory for the removal of carbon contamination from optical surfaces. A high cleaning rate could be achieved by producing an oxygen plasma close to the optical elements with special care taken to avoid any harmful effects from the discharge; contaminant carbon was completely removed within a few hours, at most. This short exposure time and the use of dry oxygen gas resulted in a restoration of the original ultrahigh vacuum without a bakeout. Results with a Seya-Namioka beamline for gas-phase experiments showed a flux enhancement amounting to a factor of 50, and results with a grasshopper beamline showed a nearly complete recovery of the light intensity, even at the carbon K edge.

  15. In situ dc oxygen‐discharge cleaning system for optical elements

    SciTech Connect

    Koide, Tsuneharu; Shidara, Tetsuo; Tanaka, Kenichiro; Yagishita, Akira; Sato, Shigeru

    1989-07-15

    In situ dc oxygen‐discharge cleaning arrangements have been developed at the Photon Factory for the removal of carbon contamination from optical surfaces. A high cleaning rate could be achieved by producing an oxygen plasma close to the optical elements with special care taken to avoid any harmful effects from the discharge; contaminant carbon was completely removed within a few hours, at most. This short exposure time and the use of dry oxygen gas resulted in a restoration of the original ultrahigh vacuum without a bakeout. Results with a Seya‐Namioka beamline for gas‐phase experiments showed a flux enhancement amounting to a factor of 50, and results with a grasshopper beamline showed a nearly complete recovery of the light intensity, even at the carbon K edge.

  16. New classification of directly compressible (DC) excipients in function of the SeDeM Diagarm Expert System.

    PubMed

    Suñé-Negre, Josep M; Roig, Manel; Fuster, Roser; Hernández, Carmen; Ruhí, Ramon; García-Montoya, Encarna; Pérez-Lozano, Pilar; Miñarro, Montserrat; Ticó, Josep R

    2014-08-15

    As a methodology for characterizing substances with regard to its viability in direct compression, the SeDeM Diagram Expert System may be considered a new tool in terms of the number of parameters applied and its optimization. The paper is based on the experimental SeDeM characterization study of 51 directly compressible (DC) excipients. After selecting the parameters, and comparing the corresponding results, the choices available within the SeDeM Expert System could be expanded. Through applied variants, the maximum and optimal values of the DC diluent excipient were precisely defined and the mathematical limits of the parameters, functions and parametric indices that define the level of direct compressibility were established. These studies have allowed us to propose a new classification of excipients CD based on its rheological and compressibility capability, resulting in a periodic table of CD excipients. It has been determined that the best excipient for direct compression should have an index of good compression (IGC) of 8.832. PMID:24792976

  17. Precision wire feeder for small diameter wire

    SciTech Connect

    Brandon, E.D.; Hooper, F.M.; Reichenbach, M.L.

    1990-12-31

    This invention is comprised of a device for feeding small diameter wire having a diameter less than .04 mm (16 mil) to a welding station which includes a driving wheel for controllably applying a non-deforming driving force to the wire to move the free end of the wire towards the welding station; and a tension device such as a torque motor for constantly applying a reverse force to the wire in opposition to the driving force to keep the wire taut. 1 fig.

  18. High performance dc-dc conversion with voltage multipliers

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T.; Myers, I. T.

    1974-01-01

    The voltage multipliers using capacitors and diodes first developed by Cockcroft and Walton in 1932 were reexamined in terms of state of the art fast switching transistors and diodes, and high energy density capacitors. Because of component improvements, the voltage multiplier, used without a transformer, now appears superior in weight to systems now in use for dc-dc conversion. An experimental 100-watt 1000-volt dc-dc converter operating at 100 kHz was built, with a component weight of about 1 kg/kW. Calculated and measured values of output voltage and efficiency agreed within experimental error.

  19. The Quantum Socket: Wiring for Superconducting Qubits - Part 1

    NASA Astrophysics Data System (ADS)

    McConkey, T. G.; Bejanin, J. H.; Rinehart, J. R.; Bateman, J. D.; Earnest, C. T.; McRae, C. H.; Rohanizadegan, Y.; Shiri, D.; Mariantoni, M.; Penava, B.; Breul, P.; Royak, S.; Zapatka, M.; Fowler, A. G.

    Quantum systems with ten superconducting quantum bits (qubits) have been realized, making it possible to show basic quantum error correction (QEC) algorithms. However, a truly scalable architecture has not been developed yet. QEC requires a two-dimensional array of qubits, restricting any interconnection to external classical systems to the third axis. In this talk, we introduce an interconnect solution for solid-state qubits: The quantum socket. The quantum socket employs three-dimensional wires and makes it possible to connect classical electronics with quantum circuits more densely and accurately than methods based on wire bonding. The three-dimensional wires are based on spring-loaded pins engineered to insure compatibility with quantum computing applications. Extensive design work and machining was required, with focus on material quality to prevent magnetic impurities. Microwave simulations were undertaken to optimize the design, focusing on the interface between the micro-connector and an on-chip coplanar waveguide pad. Simulations revealed good performance from DC to 10 GHz and were later confirmed against experimental measurements.

  20. Ensuring Wire Alignment for the New COMPASS Drift Chamber

    NASA Astrophysics Data System (ADS)

    Cromis, Megan; Compass Dc5 Team

    2014-09-01

    COMPASS is a fixed-target experiment at CERN investigating the internal structure of the proton. Polarized Drell-Yan measurements at COMPASS will explore how the quark orbital angular momentum contributes to the spin of the proton. To enable this measurement, several straw tube chambers need to be replaced due to long term wear. One of the replacement chambers, drift chamber DC5, is being built at Old Dominion University based on a prototype from UIUC and existing COMPASS drift chambers. DC5 consists of 4 wire planes with 513 wires (256 [20 μm] sense wires and 257 [100 μm] field wires alternating) and 4 wire planes at a 10 degree offset with 641 wires each. Each of these 4616 wires need to be aligned within either 100 μm (sense wire) or 200 μm (field wire) of the center of the solder pad to ensure the accuracy of the drift chamber. Problems that arose during stringing include initial alignment of the wire and efficient soldering techniques. Also, because the field wires charged at -1750 volts will be 4 mm from the sense wires, there should be no gaps or points in the solder to prevent arcing. This poster will discuss the alignment techniques, soldering methods, testing, and repair process for the wires. COMPASS is a fixed-target experiment at CERN investigating the internal structure of the proton. Polarized Drell-Yan measurements at COMPASS will explore how the quark orbital angular momentum contributes to the spin of the proton. To enable this measurement, several straw tube chambers need to be replaced due to long term wear. One of the replacement chambers, drift chamber DC5, is being built at Old Dominion University based on a prototype from UIUC and existing COMPASS drift chambers. DC5 consists of 4 wire planes with 513 wires (256 [20 μm] sense wires and 257 [100 μm] field wires alternating) and 4 wire planes at a 10 degree offset with 641 wires each. Each of these 4616 wires need to be aligned within either 100 μm (sense wire) or 200 μm (field wire) of the center of the solder pad to ensure the accuracy of the drift chamber. Problems that arose during stringing include initial alignment of the wire and efficient soldering techniques. Also, because the field wires charged at -1750 volts will be 4 mm from the sense wires, there should be no gaps or points in the solder to prevent arcing. This poster will discuss the alignment techniques, soldering methods, testing, and repair process for the wires. This research was supported in part by the DOE under Grant Number DE-FG03-94ER40860.

  1. Auxiliary resonant DC tank converter

    DOEpatents

    Peng, Fang Z.

    2000-01-01

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  2. 30 CFR 75.1003 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 75.1003 Section 75.1003... Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. Trolley wires, trolley feeder wires, and bare signal wires shall be...

  3. 30 CFR 75.1003 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 75.1003 Section 75.1003... Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley wires and trolley feeder wires. Trolley wires, trolley feeder wires, and bare signal wires shall be...

  4. Windows: Life after Wire.

    ERIC Educational Resources Information Center

    Razwick, Jerry

    2003-01-01

    Although wired glass is extremely common in school buildings, the International Building Code adopted new standards that eliminate the use of traditional wired glass in K-12 schools, daycare centers, and athletic facilities. Wired glass breaks easily, and the wires can cause significant injuries by forming dangerous snags when the glass breaks.…

  5. Windows: Life after Wire.

    ERIC Educational Resources Information Center

    Razwick, Jerry

    2003-01-01

    Although wired glass is extremely common in school buildings, the International Building Code adopted new standards that eliminate the use of traditional wired glass in K-12 schools, daycare centers, and athletic facilities. Wired glass breaks easily, and the wires can cause significant injuries by forming dangerous snags when the glass breaks.

  6. Wire insulation defect detector

    NASA Technical Reports Server (NTRS)

    Greulich, Owen R. (Inventor)

    2004-01-01

    Wiring defects are located by detecting a reflected signal that is developed when an arc occurs through the defect to a nearby ground. The time between the generation of the signal and the return of the reflected signal provides an indication of the distance of the arc (and therefore the defect) from the signal source. To ensure arcing, a signal is repeated at gradually increasing voltages while the wire being tested and a nearby ground are immersed in a conductive medium. In order to ensure that the arcing occurs at an identifiable time, the signal whose reflection is to be detected is always made to reach the highest potential yet seen by the system.

  7. The UT 19-channel DC SQUID based neuromagnetometer.

    PubMed

    ter Brake, H J; Flokstra, J; Jaszczuk, W; Stammis, R; van Ancum, G K; Martinez, A; Rogalla, H

    1991-01-01

    A 19-channel DC SQUID based neuromagnetometer is under construction at the University of Twente (UT). Except for the cryostat all elements of the system are developed at the UT. It comprises 19 wire-wound first-order gradiometers in a hexagonal configuration. The gradiometers are connected to planar DC SQUIDs fabricated with a Nb/Al, AlO kappa/Nb technology. For this connection we developed a method to bond a Nb wire to a Nb thin-film. The SQUIDs are placed in compartmentalised Nb modules. Further, external feedback is incorporated in order to eliminate cross talk between the gradiometers. The electronics basically consist of a phase-locked loop operating with a modulation frequency of 100 kHz. Between SQUID and preamplifier a small transformer is used to limit the noise contribution of the preamplifier. In the paper the overall system is described, and special attention is paid to the SQUID module (bonding, compartments, external-feedback setup, output transformer). PMID:1807878

  8. A learning flight control system for the F8-DFBW aircraft. [Digital Fly-By-Wire

    NASA Technical Reports Server (NTRS)

    Montgomery, R. C.; Mekel, R.; Nachmias, S.

    1978-01-01

    This report contains a complete description of a learning control system designed for the F8-DFBW aircraft. The system is parameter-adaptive with the additional feature that it 'learns' the variation of the control system gains needed over the flight envelope. It, thus, generates and modifies its gain schedule when suitable data are available. The report emphasizes the novel learning features of the system: the forms of representation of the flight envelope and the process by which identified parameters are used to modify the gain schedule. It contains data taken during piloted real-time 6 degree-of-freedom simulations that were used to develop and evaluate the system.

  9. High-angle tilt boundary graphene domain recrystallized from mobile hot-wire-assisted chemical vapor deposition system.

    PubMed

    Lee, Jinsup; Baek, Jinwook; Ryu, Gyeong Hee; Lee, Mi Jin; Oh, Seran; Hong, Seul Ki; Kim, Bo-Hyun; Lee, Seok-Hee; Cho, Byung Jin; Lee, Zonghoon; Jeon, Seokwoo

    2014-08-13

    Crystallization of materials has attracted research interest for a long time, and its mechanisms in three-dimensional materials have been well studied. However, crystallization of two-dimensional (2D) materials is yet to be challenged. Clarifying the dynamics underlying growth of 2D materials will provide the insight for the potential route to synthesize large and highly crystallized 2D domains with low defects. Here, we present the growth dynamics and recrystallization of 2D material graphene under a mobile hot-wire assisted chemical vapor deposition (MHW-CVD) system. Under local but sequential heating by MHW-CVD system, the initial nucleation of nanocrystalline graphenes, which was not extended into the growth stage due to the insufficient thermal energy, took a recrystallization and converted into a grand single crystal domain. During this process, the stitching-like healing of graphene was also observed. The local but sequential endowing thermal energy to nanocrystalline graphenes enabled us to simultaneously reveal the recrystallization and healing dynamics in graphene growth, which suggests an alternative route to synthesize a highly crystalline and large domain size graphene. Also, this recrystallization and healing of 2D nanocrystalline graphenes offers an interesting insight on the growth mechanism of 2D materials. PMID:24978293

  10. Stretched Wire Mechanics

    SciTech Connect

    Bowden, Gordon; /SLAC

    2005-09-06

    Stretched wires are beginning to play an important role in the alignment of accelerators and synchrotron light sources. Stretched wires are proposed for the alignment of the 130 meter long LCLS undulator. Wire position technology has reached sub-micron resolution yet analyses of perturbations to wire straightness are hard to find. This paper considers possible deviations of stretched wire from the simple 2-dimensional catenary form.

  11. DC attenuation meter

    SciTech Connect

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  12. Adjustable Bracket For Entry Of Welding Wire

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.; Gutow, David A.

    1993-01-01

    Wire-entry bracket on welding torch in robotic welding system provides for adjustment of angle of entry of welding wire over range of plus or minus 30 degrees from nominal entry angle. Wire positioned so it does not hide weld joint in view of through-the-torch computer-vision system part of robot-controlling and -monitoring system. Swiveling bracket also used on nonvision torch on which wire-feed-through tube interferes with workpiece. Angle simply changed to one giving sufficient clearance.

  13. DC coupled Doppler radar physiological monitor.

    PubMed

    Zhao, Xi; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    One of the challenges in Doppler radar systems for physiological monitoring is a large DC offset in baseband outputs. Typically, AC coupling is used to eliminate this DC offset. Since the physiological signals of interest include frequency content near DC, it is not desirable to simply use AC coupling on the radar outputs. While AC coupling effectively removes DC offset, it also introduces a large time delay and distortion. This paper presents the first DC coupled IQ demodulator printed circuit board (PCB) design and measurements. The DC coupling is achieved by using a mixer with high LO to RF port isolation, resulting in a very low radar DC offset on the order of mV. The DC coupled signals from the PCB radar system were successfully detected with significant LNA gain without saturation. Compared to the AC coupled results, the DC coupled results show great advantages of less signal distortion and more accurate rate estimation. PMID:22254704

  14. HTS Wire Development Workshop: Proceedings

    SciTech Connect

    Not Available

    1994-07-01

    The 1994 High-Temperature Superconducting Wire Development Workshop was held on February 16--17 at the St. Petersburg Hilton and Towers in St. Petersburg, Florida. The meeting was hosted by Florida Power Corporation and sponsored by the US Department of Energy`s Superconductivity Program for Electric Power Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. The meeting opened with a general discussion on the needs and benefits of superconductivity from a utility perspective, the US global competitiveness position, and an outlook on the overall prospects of wire development. The meeting then focused on four important technology areas: Wire characterization: issues and needs; technology for overcoming barriers: weak links and flux pinning; manufacturing issues for long wire lengths; and physical properties of HTS coils. Following in-depth presentations, working groups were formed in each technology area to discuss the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

  15. Ionic wind generation by a wire-cylinder-plate corona discharge in air at atmospheric pressure

    SciTech Connect

    Colas, Dorian F.; Ferret, Antoine; Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-11-15

    A wire-cylinder-plate electrode configuration is presented to generate ionic wind with a dc corona discharge in air at atmospheric pressure. The objective of the work is to maximize the power supplied to the flow in order to increase acceleration while avoiding breakdown. Thus, the proposed experimental setup addresses the problem of decoupling the mechanism of ion generation from that of ion acceleration. Using a wire-plate configuration as a reference, we have focused on improving the topography of the electric field to (1) separate the ionization and acceleration zones in space, and (2) guide the trajectory of charged particles as parallel to the median axis as possible. In the proposed wire-cylinder-plate setup, a dc corona discharge is generated in the space between a wire and two cylinders. The ions produced by the corona then drift past the cylinders and into a channel between two plates, where they undergo acceleration. To maximize the ionic wind it is found that the geometric configuration must be as compact as possible and that the voltage applied must be right below breakdown. Experimentally, the optimized wire-plate reference setup provides a maximum flow velocity of 8 m s{sup -1}, a flow rate per unit electrode length of 0.034 m{sup 2} s{sup -1}, and a thrust per unit electrode length of 0.24 N m{sup -1}. The wire-cylinder-plate configuration provides a maximum flow velocity of 10 m s{sup -1}, a flow rate per unit electrode length of 0.041 m{sup 2} s{sup -1}, and a thrust per unit electrode length of 0.35 N m{sup -1}. This 46% increase in thrust is obtained by increasing the electric power per unit electrode length by only 16% (from 175 to 210 W m{sup -1}), which confirms the gain in efficiency obtained with the decoupled system. In comparison with a simple wire-wire corona configuration, the wire-cylinder-plate configuration increases the ionic wind velocity by up to a factor of 3, and the thrust by an order of magnitude.

  16. DC arc weld starter

    DOEpatents

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  17. A novel N-input voting algorithm for X-by-wire fault-tolerant systems.

    PubMed

    Karimi, Abbas; Zarafshan, Faraneh; Al-Haddad, S A R; Ramli, Abdul Rahman

    2014-01-01

    Voting is an important operation in multichannel computation paradigm and realization of ultrareliable and real-time control systems that arbitrates among the results of N redundant variants. These systems include N-modular redundant (NMR) hardware systems and diversely designed software systems based on N-version programming (NVP). Depending on the characteristics of the application and the type of selected voter, the voting algorithms can be implemented for either hardware or software systems. In this paper, a novel voting algorithm is introduced for real-time fault-tolerant control systems, appropriate for applications in which N is large. Then, its behavior has been software implemented in different scenarios of error-injection on the system inputs. The results of analyzed evaluations through plots and statistical computations have demonstrated that this novel algorithm does not have the limitations of some popular voting algorithms such as median and weighted; moreover, it is able to significantly increase the reliability and availability of the system in the best case to 2489.7% and 626.74%, respectively, and in the worst case to 3.84% and 1.55%, respectively. PMID:25386613

  18. Improvement of a high current DC power supply system for testing the large scaled superconducting cables and magnets

    NASA Astrophysics Data System (ADS)

    Yamada, Shuichi; Chikaraishi, Hirotaka; Tanahashi, Shugo; Mito, Toshiyuki; Takahata, Kazuya; Yanagi, Nagato; Sakamoto, Mizuki; Nishimura, Arata; Motojima, Osamu; Yamamoto, Junya

    1994-07-01

    A dc 75 kA power supply system was constructed to test the SC (superconducting) R&D (research and development) cables and magnets for the Large Helical Device (LHD). It consists of three 25 kA unit banks. A unit bank has two double-star-rectifier connections with the inter-phase reactors. A digital feedback control method is applied to the automatic current regulation (ACR) in each unit bank. For shortening the dead time of the feedback process, a new algorithm of a digital phase controller for the ACR is investigated. A Bode diagram of the feedback process is directly measured. It is confirmed that the dead time of the feedback process is reduced to one sixth, and that the feedback gain of PID (proportional, integral and differential) compensation is improved by a factor of two from the original method.

  19. Improvement of a high current DC power supply system for testing the large scaled superconducting cables and magnets

    NASA Astrophysics Data System (ADS)

    Yamada, Shuichi; Chikaraishi, Hirotaka; Tanahashi, Shugo

    1993-11-01

    A dc 75 kA power supply system was constructed to test the superconducting (SC) R and D cables and magnets for the Large Helical Device. It consists of three 25 kA unit banks. A unit bank has two double-star-rectifier connections with the inter-phase reactors. A digital feedback control method is applied to the automatic current regulation (ACR) in each unit bank. For shortening the dead time of the feedback process, a new algorithm of a digital phase controller for the ACR is investigated. A Bode diagram of the feedback process is directly measured. It is confirmed that the dead time of the feedback process is reduced to one sixth, and that the feedback gain of PID compensation is improved by a factor of two from the original method.

  20. Two-stage actuation system using DC motors and piezoelectric actuators for controllable industrial and automotive brakes and clutches

    NASA Astrophysics Data System (ADS)

    Neelakantan, Vijay A.; Washington, Gregory N.; Bucknor, Norman K.

    2005-05-01

    High bandwidth actuation systems that are capable of simultaneously producing relatively large forces and displacements are required for use in automobiles and other industrial applications. Conventional hydraulic actuation mechanisms used in automotive brakes and clutches are complex, inefficient and have poor control robustness. These lead to reduced fuel economy, controllability issues and other disadvantages. This paper involves the design, development, testing and control of a two-stage hybrid actuation mechanism by combining classical actuators like DC motors and advanced smart material actuators like piezoelectric actuators. The paper also discusses the development of a robust control methodology using the Internal Model Control (IMC) principle and emphasizes the robustness property of this control methodology by comparing and studying simulation and experimental results.

  1. Improvement of a high current dc power supply system for testing the large scaled superconducting cables and magnets

    SciTech Connect

    Yamada, Shuichi; Chikaraishi, Hirotaka; Tanahashi, Shugo

    1994-07-01

    A dc 75 kA power supply system was constructed to test the SC (superconducting) R and D (research and development) cables and magnets for the Large Helical Device (LHD). It consists of three 25 kA unit banks. A unit bank has two double-star-rectifier connections with the inter-phase reactors. A digital feedback control method is applied to the automatic current regulation (ACR) in each unit bank. For shortening the dead time of the feedback process, a new algorithm of a digital phase controller for the ACR is investigated. A Bode diagram of the feedback process is directly measured. It is confirmed that the dead time of the feedback process is reduced to one sixth, and that the feedback gain of PID (proportional, integral and differential) compensation is improved by a factor of two from the original method.

  2. Effect of magnetic field strength on deposition rate and energy flux in a dc magnetron sputtering system

    SciTech Connect

    Ekpe, Samuel D.; Jimenez, Francisco J.; Field, David J.; Davis, Martin J.; Dew, Steven K.

    2009-11-15

    Variations in the magnetic field strongly affect the plasma parameters in a magnetron sputtering system. This in turn affects the throughput as well as the energy flux to the substrate. The variation in the magnetic field in this study, for a dc magnetron process, is achieved by shifting the magnet assembly slightly away from the target. Measurements of the plasma parameters show that while the electron density at the substrate increases with decrease in magnetic field, the electron temperature decreases. The cooling of the electron temperature is consistent with results reported elsewhere. The deposition rate per input magnetron power is found to increase slightly with the decrease in magnetic field for the process conditions considered in this study. Results suggest that the energy flux to the substrate tends to show a general decrease with the shift in the magnet assembly.

  3. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  4. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Carpenter, K. H.

    1974-01-01

    The design, construction, and test history of a 4096 word by 18 bit random access NDRO Plated Wire Memory for use in conjunction with a spacecraft input/output and central processing unit is reported. A technical and functional description is given along with diagrams illustrating layout and systems operation. Test data is shown on the procedures and results of system level and memory stack testing, and hybrid circuit screening. A comparison of the most significant physical and performance characteristics of the memory unit versus the specified requirements is also included.

  5. Concealed wire tracing apparatus

    DOEpatents

    Kronberg, James W.

    1994-01-01

    An apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receivers position with respect to the wiring. The receivers audible signal is strongest when the receiver is directly above the wiring and the long axis of the receivers coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring's concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest.

  6. RISK D/C

    NASA Technical Reports Server (NTRS)

    Dias, W. C.

    1994-01-01

    RISK D/C is a prototype program which attempts to do program risk modeling for the Space Exploration Initiative (SEI) architectures proposed in the Synthesis Group Report. Risk assessment is made with respect to risk events, their probabilities, and the severities of potential results. The program allows risk mitigation strategies to be proposed for an exploration program architecture and to be ranked with respect to their effectiveness. RISK D/C allows for the fact that risk assessment in early planning phases is subjective. Although specific to the SEI in its present form, RISK D/C can be used as a framework for developing a risk assessment program for other specific uses. RISK D/C is organized into files, or stacks, of information, including the architecture, the hazard, and the risk event stacks. Although predefined, all stacks can be upgraded by a user. The architecture stack contains information concerning the general program alternatives, which are subsequently broken down into waypoints, missions, and mission phases. The hazard stack includes any background condition which could result in a risk event. A risk event is anything unfavorable that could happen during the course of a specific point within an architecture, and the risk event stack provides the probabilities, consequences, severities, and any mitigation strategies which could be used to reduce the risk of the event, and how much the risk is reduced. RISK D/C was developed for Macintosh series computers. It requires HyperCard 2.0 or later, as well as 2Mb of RAM and System 6.0.8 or later. A Macintosh II series computer is recommended due to speed concerns. The standard distribution medium for this package is one 3.5 inch 800K Macintosh format diskette. RISK D/C was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Macintosh and HyperCard are trademarks of Apple Computer, Inc.

  7. Chaos control for the output-constrained system by using adaptive dynamic surface technology and application to the brushless DC motor

    NASA Astrophysics Data System (ADS)

    Luo, Shaohua; Hou, Zhiwei; Chen, Zhong

    2015-12-01

    In this paper, chaos control is proposed for the output- constrained system with uncertain control gain and time delay and is applied to the brushless DC motor. Using the dynamic surface technology, the controller overcomes the repetitive differentiation of backstepping and boundedness hypothesis of pre-determined control gain by incorporating radial basis function neural network and adaptive technology. The tangent barrier Lyapunov function is employed for time-delay chaotic system to prevent constraint violation. It is proved that the proposed control approach can guarantee asymptotically stable in the sense of uniformly ultimate boundedness without constraint violation. Finally, the effectiveness of the proposed approach is demonstrated on the brushless DC motor example.

  8. Wired for behaviors: from development to function of innate limbic system circuitry

    PubMed Central

    Sokolowski, Katie; Corbin, Joshua G.

    2012-01-01

    The limbic system of the brain regulates a number of behaviors that are essential for the survival of all vertebrate species including humans. The limbic system predominantly controls appropriate responses to stimuli with social, emotional, or motivational salience, which includes innate behaviors such as mating, aggression, and defense. Activation of circuits regulating these innate behaviors begins in the periphery with sensory stimulation (primarily via the olfactory system in rodents), and is then processed in the brain by a set of delineated structures that primarily includes the amygdala and hypothalamus. While the basic neuroanatomy of these connections is well-established, much remains unknown about how information is processed within innate circuits and how genetic hierarchies regulate development and function of these circuits. Utilizing innovative technologies including channel rhodopsin-based circuit manipulation and genetic manipulation in rodents, recent studies have begun to answer these central questions. In this article we review the current understanding of how limbic circuits regulate sexually dimorphic behaviors and how these circuits are established and shaped during pre- and post-natal development. We also discuss how understanding developmental processes of innate circuit formation may inform behavioral alterations observed in neurodevelopmental disorders, such as autism spectrum disorders, which are characterized by limbic system dysfunction. PMID:22557946

  9. Plasma Sputter-type Ion Source with Wire Electrodes for Low-energy Gallium Ion Extraction

    SciTech Connect

    Vasquez, M. Jr.; Kasuya, T.; Wada, M.; Maeno, S.; Miyamoto, N.

    2011-01-07

    Low-energy ions of gallium (Ga) and argon (Ar) were extracted from a plasma sputter-type ion source system that utilized a tungsten (W) wire extractor geometry. The 90% transparent W wire extractor configuration had shown that the system was capable of producing an ion beam with the energy as low as 10 eV in a dc filament discharge and 50 eV in a radio frequency (rf) excited system. In the present investigation, Ar plasma was sustained in an ion source chamber through an inductively coupled 13.56 MHz rf power source. Negatively biased liquid Ga target suspended on a W reservoir was sputtered and postionized prior to extraction. Mass spectral analyses revealed a strong dependence of the Ga{sup +} current on the induced target bias.

  10. Wire frame to MOVIE. BYU transfer program

    SciTech Connect

    Robbins, D.; Byers, L.D.; Benner, M.S.

    1982-12-01

    At SNLA, the primary computer-aided drafting tool is the Applicon Graphics System (AGS). The data base for mechanical parts on the AGS is a wire frame model. This report summarizes a method of adding surface information to the wire frame and passing this information up stream to MOVIE.BYU which is on a VAX computer and is used to produce shaded graphics pictures of the AGS wire frame model on a RAMTEK 9400 display terminal.

  11. Comparison between wire and wireless EEG acquisition systems based on SSVEP in an Independent-BCI.

    PubMed

    Tello, Richard M G; Mller, Sandra M T; Bastos-Filho, Teodiano; Ferreira, Andre

    2014-01-01

    This paper presents a comparison between two different technologies of acquisition systems (BrainNet36 and Emotiv Epoc) for an Independent-BCI based on Steady-State Visual Evoked Potential (SSVEP). Two stimuli separated by a viewing angle <; 1 were used. Multivariate Synchronization Index (MSI) technique was used as feature extractor and five subjects participated in the experiments. The class is obtained through a criterion of maxima. The left and right flicker stimuli were modulated at frequencies of 8.0 and 13.0 Hz, respectively. Acquisition via BrainNet system showed better results, obtaining the highest value for accuracy (100%) and the highest ITR (35.18 bits/min). This Independent-BCI is based on covert attention. PMID:25569887

  12. Transient current pulses in rocket-extended wires used to trigger lightning

    NASA Astrophysics Data System (ADS)

    Biagi, C. J.; Uman, M. A.; Hill, J. D.; Rakov, V. A.; Jordan, D. M.

    2012-04-01

    We analyze current, electric field, and optical signatures of the sudden electrical breakdown processes (precursors) that occur at the top of the upward extending, grounded, Kevlar-covered copper wires used to artificially trigger lightning. For one launch, before the sustained upward positive leader initiated, we estimate that up to 10,000 precursors occurred (one every few hundred microseconds) with peak currents from 1 to more than 100 A. Luminosity at the wire tip was observed for 339 of 410 precursors examined in detail and, in seven cases, discharge channels developed to lengths of 3 to 8 m over times of several hundred microseconds. The measured propagation speeds of current pulses on the triggering wires were less than the speed of light, and decreased from about 2.8 × 108 m s-1 to about 2.3 × 108 m s-1with increasing wire-top heights from about 80 m to about 340 m. The triggering wire and its grounding system are modeled as uniform transmission lines with model predictions that are consistent with the measured wire-base precursor current signatures. The modeling shows that (1) the characteristic impedance of the triggering wire, the ratio of the propagating precursor voltage pulse to its associated current pulse, is between 600 and 800 Ω; (2) the 25 m ground rod grounding impedance for the peak precursor current is about 100 Ω, while the DC grounding resistance is 20 Ω; and (3) the current reflection coefficient at ground for peak precursor current is ˜0.9.

  13. Chemistry of radiation damage to wire chambers

    SciTech Connect

    Wise, J.

    1992-08-01

    Proportional counters are used to study aspects of radiation damage to wire chambers (wire aging). Principles of low-pressure, rf plasma chemistry are used to predict the plasma chemistry in electron avalanches (1 atm, dc). (1) Aging is studied in CF{sub 4}/iC{sub 4}H{sub 10} gas mixtures. Wire deposits are analyzed by Auger electron spectroscopy. An apparent cathode aging process resulting in loss of gain rather than in a self-sustained current is observed in CF{sub 4}-rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF{sub 4}, acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF{sub 4}/iC{sub 4}H{sub 10} gases. Practical guidelines suggested by the model are discussed. (2) Data are presented to suggest that trace amounts of Freons do not affect aging rates in either dimethyl ether or Ar/C{sub 2}H{sub 6}. Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl{sub 3}F) in the counter gas. An increase in the concentration of Freon 11 in dimethyl ether is caused by a distillation process in the gas supply bottle and is a natural consequence of the unequal volatilities of the two compounds.

  14. Ripple Current Reduction in DC Link Capacitor by Harmonic Control of DC/DC Converter and PWM Inverter

    NASA Astrophysics Data System (ADS)

    Okuda, Tatsuya; Urakabe, Takahiro; Tsunoda, Yoshikazu; Kikunaga, Toshiyuki; Iwata, Akihiko

    A novel technique for reducing the ripple current in a DC link capacitor by harmonic control of the DC/DC converter and PWM inverter is proposed in this paper. The proposed technique synchronizes the switching frequencies of the PWM inverter and the DC/DC converter and optimizes the phase difference of the carrier waveforms between them. The effectiveness of our technique is shown by simulation and an experiment conducted with a 10-kW PM motor drive system. In comparison to the conventional technique, the proposed technique reduces the ripple current in the DC link capacitor by 20-40% in a PWM inverter drive system with a DC/DC converter.

  15. Vibration measurements of a wire scanner - Experimental setup and models

    NASA Astrophysics Data System (ADS)

    Herranz, Juan; Barjau, Ana; Dehning, Bernd

    2016-03-01

    In the next years the luminosity of the LHC will be significantly increased. This will require a much higher accuracy of beam profile measurement than actually achievable by the current wire scanner. The new performance demands a wire travelling speed up to 20 m s-1 and a position measurement accuracy of the order of 1 μm. The vibrations of the mechanical parts of the system and particularly the vibrations of the thin carbon wire have been identified as the major error sources of wire position uncertainty. Therefore the understanding of the wire vibrations has been given high priority for the design and operation of the new device. This article presents a new strategy to measure the wire vibrations based on the piezoresistive effect of the wire itself. An electronic readout system based on a Wheatstone bridge is used to measure the variation of the carbon wire resistance, which is directly proportional to the wire elongation caused by the oscillations.

  16. Design and flight experience with a digital fly-by-wire control system using Apollo guidance system hardware on an F-8 aircraft.

    NASA Technical Reports Server (NTRS)

    Deets, D. A.; Szalai, K. J.

    1972-01-01

    This paper discusses the design and initial flight tests of the first digital fly-by-wire system to be flown in an aircraft. The system, which used components from the Apollo guidance system, was installed in an F-8 aircraft. A lunar module guidance computer is the central element in the three-axis, single-channel, multimode, digital, primary control system. An electrohydraulic triplex system providing unaugmented control of the F-8 aircraft is the only backup to the digital system. Emphasis is placed on the digital system in its role as a control augmentor, a logic processor, and a failure detector. A sampled-data design synthesis example is included to demonstrate the role of various analytical and simulation methods. The use of a digital system to implement conventional control laws was shown to be practical for flight. Logic functions coded as an integral part of the control laws were found to be advantageous. Verification of software required an extensive effort, but confidence in the software was achieved. Initial flight results showed highly successful system operation, although quantization of pilot's stick and trim were areas of minor concern from the piloting standpoint.

  17. A Wire Position Monitor System for the 1.3 FHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator

    SciTech Connect

    Eddy, N.; Fellenz, B.; Prieto, P.; Semenov, A.; Voy, D.C.; Wendt, M.; /Fermilab

    2011-08-17

    The first cryomodule for the beam test facility at the Fermilab New-Muon-Lab building is currently under RF commissioning. Among other diagnostics systems, the transverse position of the helium gas return pipe with the connected 1.3 GHz SRF accelerating cavities is measured along the {approx}15 m long module using a stretched-wire position monitoring system. An overview of the wire position monitor system technology is given, along with preliminary results taken at the initial module cooldown, and during further testing. As the measurement system offers a high resolution, we also discuss options for use as a vibration detector. An electron beam test facility, based on superconducting RF (SRF) TESLA-style cryomodules is currently under construction at the Fermilab New-Muon-Lab (NML) building. The first, so-called type III+, cryomodule (CM-1), equipped with eight 1.3 GHz nine-cell accelerating cavities was recently cooled down to 2 K, and is currently under RF conditioning. The transverse alignment of the cavity string within the cryomodule is crucial for minimizing transverse kick and beam break-up effects, generated by the high-order dipole modes of misaligned accelerating structures. An optimum alignment can only be guaranteed during the assembly of the cavity string, i.e. at room temperatures. The final position of the cavities after cooldown is uncontrollable, and therefore unknown. A wire position monitoring system (WPM) can help to understand the transverse motion of the cavities during cooldown, their final location and the long term position stability after cryo-temperatures are settled, as well as the position reproducibility for several cold-warm cycles. It also may serve as vibration sensor, as the wire acts as a high-Q resonant detector for mechanical vibrations in the low-audio frequency range. The WPM system consists out of a stretched-wire position detection system, provided with help of INFN-Milano and DESY Hamburg, and RF generation and read-out electronics, developed at Fermilab.

  18. Analytical model of molecular wire performance: A comparison of π and σ electron systems

    NASA Astrophysics Data System (ADS)

    Onipko, Alexander

    1999-04-01

    The exact closed expression of zero-temperature Ohmic conductance for heterojunctions of the type three-dimensional (3D) metal/molecule/3D metal is obtained. It is specified further in explicit forms to examine electrical transport across self-assembled monolayers of linear molecules with conjugated and saturated carbon-carbon bonds. The focus is at the role of thiol head groups in functioning of polyenes and alkanes as charge transmitters between metal pads. Both tunneling and resonance tunneling across linear hydrocarbons without and with one and two end groups have been studied as a function of the Fermi energy, strength of the metal-molecule coupling, and the molecular length. Regarding the linear-response ballistic conductance of the given type of heterostructures the predictions are: pseudoresonances in the through-molecule transmission spectrum, which are generated by sulfur end groups in the band gap of the carbon chain, and suppression of the resonance and pseudoresonance tunneling by the asymmetry of the electronic structure of the system. These and other results of the paper provide a guidance for the electrical-transport spectroscopy experiments.

  19. Wire harness twisting aid

    NASA Technical Reports Server (NTRS)

    Casey, E. J.; Commadore, C. C.; Ingles, M. E.

    1980-01-01

    Long wire bundles twist into uniform spiral harnesses with help of simple apparatus. Wires pass through spacers and through hand-held tool with hole for each wire. Ends are attached to low speed bench motor. As motor turns, operator moves hand tool away forming smooth twists in wires between motor and tool. Technique produces harnesses that generate less radio-frequency interference than do irregularly twisted cables.

  20. Transport Through Carbon Nanotube Wires

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Kwak, Dochan (Technical Monitor)

    2001-01-01

    This viewgraph presentation deals with the use of carbon nanotubes as a transport system. Contact, defects, tubular bend, phonons, and mechanical deformations all contribute to reflection within the nanotube wire. Bragg reflection, however, is native to an ideal energy transport system. Transmission resistance depends primarily on the level of energy present. Finally, the details regarding coupling between carbon nanotubes and simple metals are presented.

  1. A Practical Monitoring System for the Structural Safety of Mega-Trusses Using Wireless Vibrating Wire Strain Gauges

    PubMed Central

    Park, Hyo Seon; Lee, Hwan Young; Choi, Se Woon; Kim, Yousok

    2013-01-01

    Sensor technologies have been actively employed in structural health monitoring (SHM) to evaluate structural safety. To provide stable and real-time monitoring, a practical wireless sensor network system (WSNS) based on vibrating wire strain gauges (VWSGs) is proposed and applied to a building under construction. In this WSNS, the data measured from each VWSG are transmitted to the sensor node via a signal line and then transmitted to the master node through a short-range wireless communication module (operating on the Industrial, Scientific, and Medical (ISM) band). The master node also employs a long-range wireless communication module (Code Division Multiple Access—CDMA) to transmit the received data from the sensor node to a server located in a remote area, which enables a manager to examine the measured data in real time without any time or location restrictions. In this study, a total of 48 VWSGs, 14 sensor nodes, and seven master nodes were implemented to measure long-term strain variations of mega-trusses in an irregular large-scale building under construction. Based on strain data collected over a 16-month period, a quantitative evaluation of the construction process was performed to determine the aspects that exhibit the greatest influence on member behavior and to conduct a comparison with numerical simulation results. The effect of temperature stress on the structural elements was also analyzed. From these observations, the feasibility of a long-term WSNS based on VWSGs to evaluate the structural safety of an irregular building under construction was confirmed. PMID:24351640

  2. A practical monitoring system for the structural safety of mega-trusses using wireless vibrating wire strain gauges.

    PubMed

    Park, Hyo Seon; Lee, Hwan Young; Choi, Se Woon; Kim, Yousok

    2013-01-01

    Sensor technologies have been actively employed in structural health monitoring (SHM) to evaluate structural safety. To provide stable and real-time monitoring, a practical wireless sensor network system (WSNS) based on vibrating wire strain gauges (VWSGs) is proposed and applied to a building under construction. In this WSNS, the data measured from each VWSG are transmitted to the sensor node via a signal line and then transmitted to the master node through a short-range wireless communication module (operating on the Industrial, Scientific, and Medical (ISM) band). The master node also employs a long-range wireless communication module (Code Division Multiple Access-CDMA) to transmit the received data from the sensor node to a server located in a remote area, which enables a manager to examine the measured data in real time without any time or location restrictions. In this study, a total of 48 VWSGs, 14 sensor nodes, and seven master nodes were implemented to measure long-term strain variations of mega-trusses in an irregular large-scale building under construction. Based on strain data collected over a 16-month period, a quantitative evaluation of the construction process was performed to determine the aspects that exhibit the greatest influence on member behavior and to conduct a comparison with numerical simulation results. The effect of temperature stress on the structural elements was also analyzed. From these observations, the feasibility of a long-term WSNS based on VWSGs to evaluate the structural safety of an irregular building under construction was confirmed. PMID:24351640

  3. Laser Wire Stripper

    NASA Technical Reports Server (NTRS)

    1983-01-01

    NASA-developed space shuttle technology is used in a laser wire stripper designed by Raytheon Company. Laser beams cut through insulation on a wire without damaging conductive metal, because laser radiation that melts plastic insulation is reflected by the metal. The laser process is fast, clean, precise and repeatable. It eliminates quality control problems and the expense of rejected wiring.

  4. Sensitive and simple method for measuring wire tensions

    SciTech Connect

    Atac, M.; Mishina, M.

    1982-08-01

    Measuring tension of wires in drift chambers and multiwire proportional chambers after construction is an important process because sometimes wires get loose after soldering, crimping or glueing. One needs to sort out wires which have tensions below a required minimum value to prevent electrostatic instabilities. There have been several methods reported on this subject in which the wires were excited either with sinusoidal current under magnetic field or with sinusoidal voltage electrostatically coupled to the wire, searching for a resonating frequency with which the wires vibrate mechanically. Then the vibration is detected either visually, optically or with magnetic pick-up directly touching the wires. Any of these is only applicable to the usual multiwire chamber which has open access to the wire plane. They also need fairly large excitation currents to induce a detectable vibration to the wires. Here we report a very simple method that can be used for any type of wire chamber or proportional tube system for measuring wire tension. Only a very small current is required for the wire excitation to obtain a large enough signal because it detects the induced emf voltage across a wire. A sine-wave oscillator and a digital voltmeter are sufficient devices aside from a permanent magnet to provide the magnetic field around the wire. A useful application of this method to a large system is suggested.

  5. Reprint of “Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS”

    NASA Astrophysics Data System (ADS)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

    2013-01-01

    The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

  6. An ECF sigma factor mediated cell surface signaling system in Pseudomonas syringae pv. tomato DC3000 regulates gene expression in response to heterologous siderophores

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diversity of regulatory systems encoded by bacteria provides an indication of the variety of stresses and interactions that these organisms encounter in nature. We have been investigating how the plant pathogen, Pseudomonas syringae pv. tomato DC3000, responds to iron limitation and have focuse...

  7. GENOME-WIDE IDENTIFICATION OF PROTEINS SECRETED BY THE HRP TYPE III SECRETION SYSTEM OF PSEUDOMONAS SYRINGAE PV. TOMATO DC3000

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of Pseudomonas syringae pv. tomato DC3000 to be pathogenic on plants is dependent on the Hrp type III protein secretion system and, collectively, the effector proteins translocated into plant cells. A genome wide search for Hrp effectors was performed based on patterns in the N terminal...

  8. A survey of the Pseudomonas syringae pv. tomato DC3000 type III secretion system effector repertoire reveals several effectors that are deleterious when expressed in Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The injection of nearly 30 effector proteins by the type III secretion system underlies the ability of Pseudomonas syringae pv. tomato strain DC3000 to cause disease in tomato and other host plants. The search for effector functions is complicated by redundancy within the repertoire and by plant R-g...

  9. Modular Wiring Offers Cost Savings and Future Flexibility.

    ERIC Educational Resources Information Center

    Ewald, Mike; Ewald, Ann O'Connor

    2002-01-01

    Discusses the advantages of modular wiring, a prefabricated wiring system that replaces branch circuits in buildings. Advantages include on-site and day-to-day labor savings, and future technology cost advantages. Includes questions to ask manufacturers. (EV)

  10. Terahertz wave amplification, stimulated by dc electric current, in grating coupled low-dimensional electron systems

    NASA Astrophysics Data System (ADS)

    Mikhailov, S. A.; Savostianova, N. A.

    1997-09-01

    We present an analytic theory of the transmission of electromagnetic waves through a structure "two-dimensional electron system with a flowing current - grating coupler." The transmission coefficient T(ω,vdr) is calculated as a function of frequency, drift velocity vdr, and other physical and geometrical parameters of the structure. Threshold conditions for amplification [T(ω,vdr)>1] are analyzed. A number of ideas for a reduction of the threshold velocity and an enhancement of the amplification are proposed. Our results can be used for designing tunable solid-state terahertz wave amplifiers (generators), based on the grating coupled low-dimensional electron systems.

  11. The Use of Software Agents for Autonomous Control of a DC Space Power System

    NASA Technical Reports Server (NTRS)

    May, Ryan D.; Loparo, Kenneth A.

    2014-01-01

    In order to enable manned deep-space missions, the spacecraft must be controlled autonomously using on-board algorithms. A control architecture is proposed to enable this autonomous operation for an spacecraft electric power system and then implemented using a highly distributed network of software agents. These agents collaborate and compete with each other in order to implement each of the control functions. A subset of this control architecture is tested against a steadystate power system simulation and found to be able to solve a constrained optimization problem with competing objectives using only local information.

  12. High-Efficiency dc/dc Converter

    NASA Technical Reports Server (NTRS)

    Sturman, J.

    1982-01-01

    High-efficiency dc/dc converter has been developed that provides commonly used voltages of plus or minus 12 Volts from an unregulated dc source of from 14 to 40 Volts. Unique features of converter are its high efficiency at low power level and ability to provide output either larger or smaller than input voltage.

  13. 46 CFR 129.340 - Cable and wiring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Cable and wiring. 129.340 Section 129.340 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems § 129.340 Cable and wiring. (a) If individual wires, rather than cables, are used in systems operating at...

  14. Wire-Guide Manipulator For Automated Welding

    NASA Technical Reports Server (NTRS)

    Morris, Tim; White, Kevin; Gordon, Steve; Emerich, Dave; Richardson, Dave; Faulkner, Mike; Stafford, Dave; Mccutcheon, Kim; Neal, Ken; Milly, Pete

    1994-01-01

    Compact motor drive positions guide for welding filler wire. Drive part of automated wire feeder in partly or fully automated welding system. Drive unit contains three parallel subunits. Rotations of lead screws in three subunits coordinated to obtain desired motions in three degrees of freedom. Suitable for both variable-polarity plasma arc welding and gas/tungsten arc welding.

  15. Development, implementation, and characterization of a standalone embedded viscosity measurement system based on the impedance spectroscopy of a vibrating wire sensor

    NASA Astrophysics Data System (ADS)

    Santos, José; Janeiro, Fernando M.; Ramos, Pedro M.

    2015-10-01

    This paper presents an embedded liquid viscosity measurement system based on a vibrating wire sensor. Although multiple viscometers based on different working principles are commercially available, there is still a market demand for a dedicated measurement system capable of performing accurate, fast measurements and requiring little or no operator training for simple systems and solution monitoring. The developed embedded system is based on a vibrating wire sensor that works by measuring the impedance response of the sensor, which depends on the viscosity and density of the liquid in which the sensor is immersed. The core of the embedded system is a digital signal processor (DSP) which controls the waveform generation and acquisitions for the measurement of the impedance frequency response. The DSP also processes the acquired waveforms and estimates the liquid viscosity. The user can interact with the measurement system through a keypad and an LCD or through a computer with a USB connection for data logging and processing. The presented system is tested on a set of viscosity standards and the estimated values are compared with the standard manufacturer specified viscosity values. A stability study of the measurement system is also performed.

  16. AC/DC Power Systems with Applications in Future Human Habitat on Lunar and Mars Bases

    NASA Astrophysics Data System (ADS)

    Chowdhury, Badrul H.; Hossain, Sabbir A.; Lawrence, James T.; Barave, Sushant

    2006-01-01

    As NASA readies itself for new space exploration initiatives starting with a human return to the Moon by the year 2020 eventually leading to human exploration of Mars, the requirements for a safe, efficient and comprehensive power system to support the exploration missions as well human habitat will become important issues to consider. Certain issues dealing with electric power generation and distribution on board Mars-bound vehicles and those on Lunar and Martian surfaces are described. The requirements for lightweight power generation dictates the use of a high frequency ac machine. Preliminary results of investigating the design of a permanent magnet synchronous machine is presented.

  17. General-purpose fuzzy controller for dc-dc converters

    SciTech Connect

    Mattavelli, P.; Rossetto, L.; Spiazzi, G.; Tenti, P.

    1997-01-01

    In this paper, a general-purpose fuzzy controller for dc-dc converters is investigated. Based on a qualitative description of the system to be controlled, fuzzy controllers are capable of good performances, even for those systems where linear control techniques fail, e.g., when a mathematical description is not available or is in the presence of wide parameter variations. The presented approach is general and can be applied to any dc-dc converter topologies. Controller implementation is relatively simple and can guarantee a small-signal response as fast and stable as other standard regulators and an improved large-signal response. Simulation results of Buck-Boost and Sepic converters show control potentialities.

  18. Delocalization in weakly coupled disordered wires: application to conjugated polymers.

    PubMed

    Martens, H C F

    2006-02-24

    It is well known that even for minimal disorder one-dimensional wires are insulators: all 1D electron states are localized. Here, the influence of interwire coupling on delocalization of 1D states is examined. Based on perturbation theoretic arguments for the formation of 3D states in coupled wires and subsequent scaling analysis, practical expressions for the microscopic conditions of electronic delocalization and coherent conductivity of coupled 1D wires are obtained. The model quantitatively explains the temperature dependent dc conductivity in conducting polymers at both sides of the metal-insulator transition and links the experimental data to microscopic material parameters. PMID:16606118

  19. Introduction of DC line structures into a superconducting microwave 3D cavity

    SciTech Connect

    Kong, Wei-Cheng; Deng, Guang-Wei; Li, Shu-Xiao; Li, Hai-Ou; Cao, Gang; Xiao, Ming; Guo, Guo-Ping

    2015-02-15

    We report a technique that can noninvasively add multiple DC wires into a 3D superconducting microwave cavity for electronic devices that require DC electrical terminals. We studied the influence of our DC lines on the cavity performance systematically. We found that the quality factor of the cavity is reduced if any of the components of the electrical wires cross the cavity equipotential planes. Using this technique, we were able to incorporate a quantum dot (QD) device into a 3D cavity. We then controlled and measured the QD transport signal using the DC lines. We have also studied the heating effects of the QD by the microwave photons in the cavity.

  20. Composite ceramic superconducting wires for electric motor applications

    NASA Astrophysics Data System (ADS)

    Holloran, John W.

    1989-07-01

    Progress is described on developing Y-123 wire for an HTSC motor. The wire development involves synthesis of Y-123 powder, spinning polymer containing green fiber, heat treating the fiber to produce metallized superconducting filaments, and characterizing the electrical properties. A melt spinning process was developed for producing 125-micron diameter green fiber containing 50 vol percent Y-123. This fiber can be braided for producing transposed multifilamentary wire. A process was developed to coat green fiber with silver alloys which can be continuous sintering. A second process for multifilamentary ribbon wire is also being developed. The Y-123 filaments have 77 deg self-field Jc values up to 2600 A/sq cm, but Jc is reduced to 10 A/cm squared at 800 G. Preliminary data is presented on mechanical properties. A dc homopolar motor with an iron magnetic circuit is being designed to operate with early HTSC wire.

  1. Composite ceramic superconducting wires for electric motor applications

    NASA Astrophysics Data System (ADS)

    Halloran, John W.

    1990-07-01

    Several types of HTSC wire have been produced and two types of HTSC motors are being built. Hundreds of meters of Ag- clad wire were fabricated from YBa2Cu3O(7-x) (Y-123) and Bi2Ca2Sr2Cu3O10 (BiSCCO). The dc homopolar motor coils are not yet completed, but multiple turns of wire have been wound on the coil bobbins to characterize the superconducting properties of coiled wire. Multifilamentary conductors were fabricated as cables and coils. The sintered polycrystalline wire has self-field critical current densities (Jc) as high as 2800 A/sq cm, but the Jc falls rapidly with magnetic field. To improve Jc, sintered YBCO wire is melt textured with a continuous process which has produced textures wire up to 0.5 meters long with 77K transport Jc above 11, 770 A/sq cm2 in self field and 2100 A/sq cm2 at 1 telsa. The Emerson Electric dc homopolar HTSC motor has been fabricated and run with conventional copper coils. A novel class of potential very powerful superconducting motors have been designed to use trapped flux in melt textures Y-123 as magnet replicas in an new type of permanent magnet motor. The stator element and part of the rotor of the first prototype machine exist, and the HTSC magnet replica segments are being fabricated.

  2. Health care's 100 most wired.

    PubMed

    Solovy, A; Serb, C

    1999-02-01

    They're wired all right, and America's 100 most techno-savvy hospitals and health systems share one more thing: a commitment to using technology to link with employees, patients, suppliers, and insurers. "We want to be a health care travel agency for our community," says one chief information officer. "And we see Internet technology as a key." PMID:10081454

  3. Sensitive and simple method for measuring wire tensions

    NASA Astrophysics Data System (ADS)

    Atac, M.; Mishina, M.

    1982-08-01

    Measuring tension of wires in drift chambers and multiwire proportional chambers after construction is an important process because sometimes wires get loose after soldering, crimping or glueing. Wires which have tensions below a required minimum value to prevent electrostatic instabilities are sorted out. A very simple method that can be used for any type of wire chamber or proportional tube system for measuring wire tension is reported. Only a very small current is required for the wire excitation to obtain a large enough signal because it detects the induced emf voltage across a wire. A sine-wave oscillator and a digital voltmeter are sufficient devices aside from a permanent magnet to provide the magnetic field around the wire. A useful application of this method to a large system is suggested.

  4. Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Fimmers, C.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Rittich, D.; Sammet, J.; Wlochal, M.

    2014-01-01

    A novel powering scheme based on the DC-DC conversion technique will be exploited to power the CMS Phase-1 pixel detector. DC-DC buck converters for the CMS pixel project have been developed, based on the AMIS5 ASIC designed by CERN. The powering system of the Phase-1 pixel detector is described and the performance of the converter prototypes is detailed, including power efficiency, stability of the output voltage, shielding, and thermal management. Results from a test of the magnetic field tolerance of the DC-DC converters are reported. System tests with pixel modules using many components of the future pixel barrel system are summarized. Finally first impressions from a pre-series of 200 DC-DC converters are presented.

  5. Steady-state analysis of a faulted three-phase four-wire system supplying induction motors with neutrals connected and other single-phase line-to-neutral loads

    NASA Technical Reports Server (NTRS)

    Wood, M. E.

    1980-01-01

    Four wire Wye connected ac power systems exhibit peculiar steady state fault characteristics when the fourth wire of three phase induction motors is connected. The loss of one phase of power source due to a series or shunt fault results in currents higher than anticipated on the remaining two phases. A theoretical approach to compute the fault currents and voltages is developed. A FORTRAN program is included in the appendix.

  6. 77 FR 9701 - Steel Wire Garment Hangers From Taiwan And Vietnam

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-17

    ... Commission, Washington, DC, and by publishing the notice in the Federal Register of January 6, 2012 (77 FR... COMMISSION Steel Wire Garment Hangers From Taiwan And Vietnam Determinations On the basis of the record \\1... injured by reason of imports from Taiwan and Vietnam of steel wire garment hangers, provided for...

  7. Filter line wiring designs in aircraft

    NASA Astrophysics Data System (ADS)

    Rowe, Richard M.

    1990-10-01

    The paper presents a harness design using a filter-line wire technology and appropriate termination methods to help meet high-energy radiated electromagnetic field (HERF) requirements for protection against the adverse effects of EMI on electrical and avionic systems. Filter-line interconnect harnessing systems discussed consist of high-performance wires and cables; when properly wired they suppress conducted and radiated EMI above 100 MHz. Filter-line termination devices include backshell adapters, braid splicers, and shield terminators providing 360-degree low-impedance terminations and enhancing maintainability of the system.

  8. Digital Control Technologies for Modular DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

    2002-01-01

    Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

  9. 30 CFR 77.1802 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 77.1802 Section 77.1802... Wires and Trolley Feeder Wires § 77.1802 Insulation of trolley wires, trolley feeder wires and bare..., and bare signal wires shall be adequately guarded: (a) At all points where men are required to work...

  10. 30 CFR 77.1802 - Insulation of trolley wires, trolley feeder wires and bare signal wires; guarding of trolley...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... wires and bare signal wires; guarding of trolley wires and trolley feeder wires. 77.1802 Section 77.1802... Wires and Trolley Feeder Wires § 77.1802 Insulation of trolley wires, trolley feeder wires and bare..., and bare signal wires shall be adequately guarded: (a) At all points where men are required to work...

  11. Thin wire pointing method

    NASA Technical Reports Server (NTRS)

    Green, G.; Mattauch, R. J. (Inventor)

    1983-01-01

    A method is described for forming sharp tips on thin wires, in particular phosphor bronze wires of diameters such as one-thousandth inch used to contact micron size Schottky barrier diodes, which enables close control of tip shape and which avoids the use of highly toxic solutions. The method includes dipping an end of a phosphor bronze wire into a dilute solution of sulfamic acid and applying a current through the wire to electrochemically etch it. The humidity in the room is controlled to a level of less than 50%, and the voltage applied between the wire and another electrode in the solutions is a half wave rectified voltage. The current through the wire is monitored, and the process is stopped when the current falls to a predetermined low level.

  12. Lingual straight wire method.

    PubMed

    Takemoto, Kyoto; Scuzzo, Giuseppe; Lombardo, L U C A; Takemoto, Y U I

    2009-12-01

    The mushroom arch-wire is mainly used in lingual orthodontic treatment but the complicated wire bending it requires affects both the treatment results and the time spent at the chair. The author proposes a new lingual straight wire method (LSW) in order to facilitate arch coordination and simplify the mechanics. The attention paid to the set-up model and bracket positioning and bonding plus the use of the new LSW method will also improve patient comfort. PMID:20303920

  13. Sintered wire annode

    DOEpatents

    Falce, Louis R.; Ives, R. Lawrence

    2007-12-25

    A plurality of high atomic number wires are sintered together to form a porous rod that is parted into porous disks which will be used as x-ray targets. A thermally conductive material is introduced into the pores of the rod, and when a stream of electrons impinges on the sintered wire target and generates x-rays, the heat generated by the impinging x-rays is removed by the thermally conductive material interspersed in the pores of the wires.

  14. Resistance of streamline wires

    NASA Technical Reports Server (NTRS)

    Defoe, George L

    1928-01-01

    This note contains the results of tests to determine the resistance of four sizes of streamline wire. The investigation was conducted in the six-inch wind tunnel of the National Advisory Committee for Aeronautics. The tests were made at various velocities and it was found that the resistance of streamline wires was considerably less than that of round wires of equivalent strength. Scale effect was also found since, with an increase of Reynolds Number, a decrease in the resistance coefficient was obtained.

  15. Circular photogalvanic effect induced by near-infrared radiation in InAs quantum wires patterned quasi-two-dimensional electron system

    SciTech Connect

    Jiang Chongyun; Chen Yonghai; Ma Hui; Yu Jinling; Liu Yu

    2011-06-06

    In this letter we investigated the InAs/InAlAs quantum wires (QWRs) superlattice by optically exciting the structure with near-infrared radiation. By varying the helicity of the radiation at room temperature we observed the circular photogalvanic effect related to the C{sub 2v} symmetry of the structure, which could be attributed to the formation of a quasi-two-dimensional system underlying in the vicinity of the QWRs pattern. The ratio of Rashba and Dresselhaus terms shows an evolution of the spin-orbit interaction in quasi-two-dimensional structure with the QWR layer deposition thickness.

  16. Circular photogalvanic effect induced by near-infrared radiation in InAs quantum wires patterned quasi-two-dimensional electron system

    NASA Astrophysics Data System (ADS)

    Jiang, Chongyun; Chen, Yonghai; Ma, Hui; Yu, Jinling; Liu, Yu

    2011-06-01

    In this letter we investigated the InAs/InAlAs quantum wires (QWRs) superlattice by optically exciting the structure with near-infrared radiation. By varying the helicity of the radiation at room temperature we observed the circular photogalvanic effect related to the C2v symmetry of the structure, which could be attributed to the formation of a quasi-two-dimensional system underlying in the vicinity of the QWRs pattern. The ratio of Rashba and Dresselhaus terms shows an evolution of the spin-orbit interaction in quasi-two-dimensional structure with the QWR layer deposition thickness.

  17. Wiring Damage Analyses for STS OV-103

    NASA Technical Reports Server (NTRS)

    Thomas, Walter, III

    2006-01-01

    This study investigated the Shuttle Program s belief that Space Transportation System (STS) wiring damage occurrences are random, that is, a constant occurrence rate. Using Problem Reporting and Corrective Action (PRACA)-derived data for STS Space Shuttle OV-103, wiring damage was observed to increase over the vehicle s life. Causal factors could include wiring physical deterioration, maintenance and inspection induced damage, and inspection process changes resulting in more damage events being reported. Induced damage effects cannot be resolved with existent data. Growth analysis (using Crow-AMSAA, or CA) resolved maintenance/inspection effects (e.g., heightened awareness) on all wire damages and indicated an overall increase since Challenger Return-to-Flight (RTF). An increasing failure or occurrence rate per flight cycle was seen for each wire damage mode; these (individual) rates were not affected by inspection process effects, within statistical error.

  18. Electronic transport in inhomogeneous quantum wires.

    SciTech Connect

    Rech, J.; Matveev, K. A.; Materials Science Division

    2008-04-23

    We study the transport properties of a long non-uniform quantum wire where the electron-electron interactions and the density vary smoothly at large length scales. We show that these inhomogeneities lead to a finite resistivity of the wire, due to a weak violation of momentum conservation in the collisions between electrons. Estimating the rate of change of momentum associated with non-momentum-conserving scattering processes, we derive the expression for the resistivity of the wire in the regime of weakly interacting electrons and find a contribution linear in temperature for a broad range of temperatures below the Fermi energy. By estimating the energy dissipated throughout the wire by low-energy excitations, we then develop a different method for deriving the resistivity of the wire, which can be combined with the bosonization formalism. This allows us to compare our results with previous works relying on an extension of the Tomonaga-Luttinger model to inhomogeneous systems.

  19. OTA & CCII-Based Control System of Shunt Active Power Filter Using in Three-Phase Three-wire System

    NASA Astrophysics Data System (ADS)

    Vanichprapa, Sombat; Prapanavarat, Cherdchai; Chipipop, Boonruk

    2008-10-01

    This paper presents the implementation of the OTA (Operational Transconductance Amplifier) & CCII (Second generation Current Conveyor)—based control system of active power filter (APF). The three-phase shunt PWM VSI-APF is used as the power circuit for simple control. This proposed control system using OTA & CCII-based circuits since it has the advantage of its adaptive control, real-time processing and it has wide bandwidth which can work with the high frequency power switches in order to eliminate the higher order of harmonics, moreover, it can be fabricated in one single chip by using CMOS technology. Theoretical analysis, design and simulation results are provided.

  20. DC/DC Converter Stability Testing Study

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2008-01-01

    This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

  1. Wire-inhomogeneity detector

    DOEpatents

    Gibson, G.H.; Smits, R.G.; Eberhard, P.H.

    1982-08-31

    A device for uncovering imperfections in electrical conducting wire, particularly superconducting wire, by detecting variations in eddy currents. Eddy currents effect the magnetic field in a gap of an inductor, contained in a modified commercial ferrite core, through which the wire being tested is passed. A small increase or decrease in the amount of conductive material, such as copper, in a fixed cross section of wire will unbalance a bridge used to measure the impedance of the inductor, tripping a detector and sounding an alarm.

  2. Concealed wire tracing apparatus

    DOEpatents

    Kronberg, J.W.

    1994-05-31

    An apparatus and method that combines a signal generator and a passive signal receiver to detect and record the path of partially or completely concealed electrical wiring without disturbing the concealing surface is disclosed. The signal generator applies a series of electrical pulses to the selected wiring of interest. The applied pulses create a magnetic field about the wiring that can be detected by a coil contained within the signal receiver. An audible output connected to the receiver and driven by the coil reflects the receivers position with respect to the wiring. The receivers audible signal is strongest when the receiver is directly above the wiring and the long axis of the receivers coil is parallel to the wiring. A marking means is mounted on the receiver to mark the location of the wiring as the receiver is directed over the wiring's concealing surface. Numerous marks made on various locations of the concealing surface will trace the path of the wiring of interest. 4 figs.

  3. Weld Wire Investigation Summary

    SciTech Connect

    Cunningham, M.A.

    1999-03-22

    After GTA welding reservoir A production/process prove-in assemblies, X-ray examination detected a lack of sidewall fusion. After examining several possible causes, it was determined that the weld wire filler metal was responsible, particularly the wire cleaning process. The final conclusion was that the filler wire must be abrasively cleaned in a particular manner to perform as required. The abrasive process was incorporated into the wire material specification, ensuring consistency for all reservoir GTA welding at AlliedSignal Federal Manufacturing and Technologies (FM and T).

  4. Magnetic uniaxial wire medium

    NASA Astrophysics Data System (ADS)

    Morgado, Tiago A.; Costa, João T.; Silveirinha, Mário G.

    2016-02-01

    It is shown that a racemic array of helical-shaped metallic wires may have a dual electromagnetic response, such that for arbitrarily large wavelengths it concurrently supports two modes with hyperbolic- and elliptical-type dispersions. Importantly, one of the eigenwaves is nearly dispersionless and sees the metamaterial as a medium with extreme magnetic anisotropy. The metamaterial may thus behave as the magnetic analog of the conventional wire medium formed by a set of parallel straight metallic wires. It is demonstrated that the magnetic wire medium enables channeling the subwavelength details of transverse electric (TE) polarized waves.

  5. 1998 wire development workshop proceedings

    SciTech Connect

    1998-04-01

    This report consists of vugraphs of the presentations at the conference. The conference was divided into the following sessions: (1) First Generation Wire Development: Status and Issues; (2) First Generation Wire in Pre-Commercial Prototypes; (3) Second Generation Wire Development: Private Sector Progress and Issues; (4) Second Generation Wire Development: Federal Laboratories; and (5) Fundamental Research Issues for HTS Wire Development.

  6. VIEW SOUTHEASTBUILDING 4 NO. 1 WIRE MILL (1871) WIRE DRAWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW SOUTHEAST-BUILDING 4 NO. 1 WIRE MILL (1871) WIRE DRAWING MACHINE - John A. Roebling's Sons Company & American Steel & Wire Company, South Broad, Clark, Elmer, Mott & Hudson Streets, Trenton, Mercer County, NJ

  7. Wire Array Photovoltaics

    NASA Astrophysics Data System (ADS)

    Turner-Evans, Dan

    Over the past five years, the cost of solar panels has dropped drastically and, in concert, the number of installed modules has risen exponentially. However, solar electricity is still more than twice as expensive as electricity from a natural gas plant. Fortunately, wire array solar cells have emerged as a promising technology for further lowering the cost of solar. Si wire array solar cells are formed with a unique, low cost growth method and use 100 times less material than conventional Si cells. The wires can be embedded in a transparent, flexible polymer to create a free-standing array that can be rolled up for easy installation in a variety of form factors. Furthermore, by incorporating multijunctions into the wire morphology, higher efficiencies can be achieved while taking advantage of the unique defect relaxation pathways afforded by the 3D wire geometry. The work in this thesis shepherded Si wires from undoped arrays to flexible, functional large area devices and laid the groundwork for multijunction wire array cells. Fabrication techniques were developed to turn intrinsic Si wires into full p-n junctions and the wires were passivated with a-Si:H and a-SiNx:H. Single wire devices yielded open circuit voltages of 600 mV and efficiencies of 9%. The arrays were then embedded in a polymer and contacted with a transparent, flexible, Ni nanoparticle and Ag nanowire top contact. The contact connected >99% of the wires in parallel and yielded flexible, substrate free solar cells featuring hundreds of thousands of wires. Building on the success of the Si wire arrays, GaP was epitaxially grown on the material to create heterostructures for photoelectrochemistry. These cells were limited by low absorption in the GaP due to its indirect bandgap, and poor current collection due to a diffusion length of only 80 nm. However, GaAsP on SiGe offers a superior combination of materials, and wire architectures based on these semiconductors were investigated for multijunction arrays. These devices offer potential efficiencies of 34%, as demonstrated through an analytical model and optoelectronic simulations. SiGe and Ge wires were fabricated via chemical-vapor deposition and reactive ion etching. GaAs was then grown on these substrates at the National Renewable Energy Lab and yielded ns lifetime components, as required for achieving high efficiency devices.

  8. Study on Electro-polymerization Nano-micro Wiring System Imitating Axonal Growth of Artificial Neurons towards Machine Learning

    NASA Astrophysics Data System (ADS)

    Dang, Nguyen Tuan; Akai-Kasada, Megumi; Asai, Tetsuya; Saito, Akira; Kuwahara, Yuji; Hokkaido University Collaboration

    2015-03-01

    Machine learning using the artificial neuron network research is supposed to be the best way to understand how the human brain trains itself to process information. In this study, we have successfully developed the programs using supervised machine learning algorithm. However, these supervised learning processes for the neuron network required the very strong computing configuration. Derivation from the necessity of increasing in computing ability and in reduction of power consumption, accelerator circuits become critical. To develop such accelerator circuits using supervised machine learning algorithm, conducting polymer micro/nanowires growing process was realized and applied as a synaptic weigh controller. In this work, high conductivity Polypyrrole (PPy) and Poly (3, 4 - ethylenedioxythiophene) PEDOT wires were potentiostatically grown crosslinking the designated electrodes, which were prefabricated by lithography, when appropriate square wave AC voltage and appropriate frequency were applied. Micro/nanowire growing process emulated the neurotransmitter release process of synapses inside a biological neuron and wire's resistance variation during the growing process was preferred to as the variation of synaptic weigh in machine learning algorithm. In a cooperation with Graduate School of Information Science and Technology, Hokkaido University.

  9. 650V DC ride-through system ultra capacitor version: System description and test results. Final report

    SciTech Connect

    1998-12-01

    Over the past decade, the need for effective short-term energy storage has become evident as a result of the sensitivity of modern equipment to power system disturbances. Adjustable Speed Drives (ASD) are some of the more sensitive electronic systems used in modern manufacturing facilities. The interruption of continuous processes due to the inability of the SD to ride through voltage sags or momentary outages may lead to significant financial losses. This report describes an ultracapacitor version of a ride-through system developed by Maxwell Technologies.

  10. Wire Weight with Housing

    Wire weight is lowered to water surface to measure stage at a site. Levels are made to the wire weights elevation from known benchmarks to ensure correct readings. In the background there is housing protected with dikes along the Missouri River in Mandan, ND....

  11. The exploding wire phenomenon

    NASA Astrophysics Data System (ADS)

    Aspden, H.

    1985-02-01

    Graneau's recent interpretation of the exploding wire phenomenon as an electrodynamic effect verifying Ampère's classical formulation is questioned. Instead, it is shown that the rupturing force arising from the imbalance of the self-induced electromotive force and the ohmic potential during an explosive current surge will account for the wire breaking into several segments, as is observed.

  12. Commercial and Industrial Wiring.

    ERIC Educational Resources Information Center

    Kaltwasser, Stan; Flowers, Gary

    This module is the third in a series of three wiring publications, includes additional technical knowledge and applications required for job entry in the commercial and industrial wiring trade. The module contains 15 instructional units that cover the following topics: blueprint reading and load calculations; tools and equipment; service;…

  13. Tap into the Wires.

    ERIC Educational Resources Information Center

    Jones, Dick

    1986-01-01

    A story on the wire services puts an institution's name before editors and news directors at media outlets all over the state and region and maybe even across the nation. To get potential stories onto the wires, the development officer needs to have sound news judgment, the ability to write clearly, and tact. (MLW)

  14. Qualitative comparison of calculated turbulence responses with wind-tunnel measurements for a DC-10 derivative wing with an active control system

    NASA Technical Reports Server (NTRS)

    Perry, B., III

    1981-01-01

    This paper presents comparisons of analytically-predicted and experimental turbulence responses of a wind-tunnel model of a DC-10 derivative wing equipped with an active control system. The active control system was designed for the purpose of flutter suppression, but it had the additional benefit of alleviating gust loads (wing bending moment) by about 25 percent. Comparisons of various wing responses are presented for variations in active-control-system parameters and tunnel speed. The analytical turbulence responses were obtained using DYLOFLEX, a computer program for dynamic loads analyses of flexible airplanes with active controls. In general, the analytical predictions agreed reasonably well with the experimental data.

  15. Qualitative comparison of calculated turbulence responses with wind-tunnel measurements for a DC-10 derivative wing with an active control system

    NASA Technical Reports Server (NTRS)

    Perry, B., III

    1981-01-01

    Comparisons are presented analytically predicted and experimental turbulence responses of a wind tunnel model of a DC-10 derivative wing equipped with an active control system. The active control system was designed for the purpose of flutter suppression, but it had additional benefit of alleviating gust loads (wing bending moment) by about 25%. Comparisions of various wing responses are presented for variations in active control system parameters and tunnel speed. The analytical turbulence responses were obtained using DYLOFLEX, a computer program for dynamic loads analyses of flexible airplanes with active controls. In general, the analytical predictions agreed reasonably well with the experimental data.

  16. Wire Transport Code

    SciTech Connect

    Caporaso, G.J.; Cole, A.G.

    1983-03-01

    The Wire Transport Code was developed to study the dynamics of relativistic-electron-beam propagation in the transport tube in which a wire-conditioning zone is present. In order for the beam to propagate successfully in the transport section it must be matched onto the wire by focusing elements. The beam must then be controlled by strong lenses as it exits the wire zone. The wire transport code was developed to model this process in substantial detail. It is able to treat axially symmetric problems as well as those in which the beam is transversely displaced from the axis of the transport tube. The focusing effects of foils and various beamline lenses are included in the calculations.

  17. Microwave polarization angle study of the radiation-induced magnetoresistance oscillations in the GaAs/AlGaAs 2D electron system under dc current bias

    NASA Astrophysics Data System (ADS)

    Iqbal, Muhammad-Zahir; Liu, Han-Chun; Heimbeck, Martin S.; Everitt, Henry O.; Wegscheider, Werner; Mani, Ramesh G.

    Microwave-induced magnetoresistance oscillations followed by the vanishing resistance states are a prime representation of non-equilibrium transport phenomena in two-dimensional electron systems (2DES). The effect of a dc current bias on the nonlinear response of 2DES with microwave polarization angle under magnetic field is a subject of interest. Here, we have studied the effect of various dc current bias on microwave radiation-induced magnetoresistance oscillations in a high mobility 2DES. Further, we systematically investigate the effect of the microwave polarization angle on the magneto-resistance oscillations at two different frequencies 152.78 GHz and 185.76 GHz. This study aims to better understand the effects of both dc current and microwave polarization angle in the GaAs/AlGaAs system, both of which modify the observed magneto-transport properties DOE-BES, Mat'l. Sci. & Eng. Div., DE-SC0001762; ARO W911NF-14-2-0076; ARO W911NF-15-1-0433.

  18. Thermal conductivity modeling of circular-wire nanocomposites

    NASA Astrophysics Data System (ADS)

    Hsieh, Tse-Yang; Yang, Jaw-Yen

    2010-08-01

    A phonon Boltzmann equation solver using multiblock-structured grid system is developed and applied to study transverse thermal transport in silicon-germanium circular-wire nanocomposite (silicon nanowires embedded in germanium host matrix). Past studies usually assume geometric simplification for the circular-wire nanocomposite, so the heat transfer is actually modeled in a square-wire nanocomposite. To demonstrate geometry effect, phonon transport in both the circular-wire and square-wire nanocomposites are investigated with various wire spacings, volume fractions, and dimensions. In ballistic phonon transport, due to the smoothness of circular shape, the circular wire imposes less thermal resistance than the square wire. Nevertheless, in the geometric simplification, the wire spacing of the square-wire nanocomposite is larger than that of the circular-wire nanocomposite. The usual geometric simplification can overestimate the thermal conductivity of the circular-wire nanocomposite. The obtained results can provide essential information for the development of bulk-nanostructured thermoelectric devices.

  19. NASA requirements and applications environments for electrical power wiring

    NASA Technical Reports Server (NTRS)

    Stavnes, Mark W.; Hammoud, Ahmad N.

    1992-01-01

    Serious problems can occur from insulation failures in the wiring harnesses of aerospace vehicles. In most recorded incidents, the failures have been identified to be the result of arc tracking, the propagation of an arc along wiring bundles through degradation of insulation. Propagation of the arc can lead to the loss of the entire wiring harness and the functions which it supports. While an extensive database of testing for arc track resistant wire insulations has been developed for aircraft applications, the counterpart requirements for spacecraft are very limited. The electrical, thermal, mechanical, chemical, and operational requirements for specification and testing of candidate wiring systems for spacecraft applications is presented.

  20. Unmodulated spin chains as universal quantum wires

    SciTech Connect

    Wojcik, Antoni; Kurzynski, Pawel; Grudka, Andrzej; Luczak, Tomasz; Gdala, Tomasz; Bednarska, Malgorzata

    2005-09-15

    We study a quantum state transfer between two qubits interacting with the ends of a quantum wire consisting of linearly arranged spins coupled by an excitation conserving, time-independent Hamiltonian. We show that, if we control the coupling between the source and the destination qubits and the ends of the wire, the evolution of the system can lead to an almost perfect transfer even in the case in which all nearest-neighbour couplings between the internal spins of the wire are equal.

  1. Conductance of fully equilibrated quantum wires.

    SciTech Connect

    Rech, J.; Micklitz, T.; Matveev, K. A.; Materials Science Division; Arnold Sommerfeld Center for Theoretical Physics; Ludwig-Maximilians-Univ.

    2009-03-20

    We study the conductance of a quantum wire in the presence of weak electron-electron scattering. In a sufficiently long wire the scattering leads to full equilibration of the electron distribution function in the frame moving with the electric current. At nonzero temperature this equilibrium distribution differs from the one supplied by the leads. As a result the contact resistance increases, and the quantized conductance of the wire acquires a quadratic in temperature correction. The magnitude of the correction is found by analysis of the conservation laws of the system and does not depend on the details of the interaction mechanism responsible for equilibration.

  2. Present Status and Future Perspective of Bismuth-Based High-Temperature Superconducting Wires Realizing Application Systems

    NASA Astrophysics Data System (ADS)

    Sato, Ken-ichi; Kobayashi, Shin-ichi; Nakashima, Takayoshi

    2012-01-01

    Among a series of high-temperature superconducting materials that have been discovered to date, (Bi,Pb)2Sr2Ca2Cu3O10-x is the best candidate for superconducting wires that are long with commercial productivity, and critical current performance. In particular, the controlled overpressure (CT-OP) sintering technique gave us a 100% density of (Bi,Pb)2Sr2Ca2Cu3O10-x portion, which leads to robustness, increase in critical current, and mechanical tolerance. Many application prototypes are already verified and are being evaluated worldwide. Current leads for large magnets and magnetic billet heaters are already commercial products. Commercial applications for power cables, motors for ship propulsion and electric vehicles, and many kinds of magnets are promising in the near future.

  3. Understanding Climate Policy Data Needs. NASA Carbon Monitoring System Briefing: Characterizing Flux Uncertainty, Washington D.C., 11 January 2012

    NASA Technical Reports Server (NTRS)

    Brown, Molly E.; Macauley, Molly

    2012-01-01

    Climate policy in the United States is currently guided by public-private partnerships and actions at the local and state levels. This mitigation strategy is made up of programs that focus on energy efficiency, renewable energy, agricultural practices and implementation of technologies to reduce greenhouse gases. How will policy makers know if these strategies are working, particularly at the scales at which they are being implemented? The NASA Carbon Monitoring System (CMS) will provide information on carbon dioxide fluxes derived from observations of earth's land, ocean and atmosphere used in state of the art models describing their interactions. This new modeling system could be used to assess the impact of specific policy interventions on CO2 reductions, enabling an iterative, results-oriented policy process. In January of 2012, the CMS team held a meeting with carbon policy and decision makers in Washington DC to describe the developing modeling system to policy makers. The NASA CMS will develop pilot studies to provide information across a range of spatial scales, consider carbon storage in biomass, and improve measures of the atmospheric distribution of carbon dioxide. The pilot involves multiple institutions (four NASA centers as well as several universities) and over 20 scientists in its work. This pilot study will generate CO2 flux maps for two years using observational constraints in NASA's state-of -the-art models. Bottom-up surface flux estimates will be computed using data-constrained land and ocean models; comparison of the different techniques will provide some knowledge of uncertainty in these estimates. Ensembles of atmospheric carbon distributions will be computed using an atmospheric general circulation model (GEOS-5), with perturbations to the surface fluxes and to transport. Top-down flux estimates will be computed from observed atmospheric CO2 distributions (ACOS/GOSAT retrievals) alongside the forward-model fields, in conjunction with an inverse approach based on the CO2 model of GEOS ]Chem. The forward model ensembles will be used to build understanding of relationships among surface flux perturbations, transport uncertainty and atmospheric carbon concentration. This will help construct uncertainty estimates and information on the true spatial resolution of the top-down flux calculations. The relationship between the top-down and bottom-up flux distributions will be documented. Because the goal of NASA CMS is to be policy relevant, the scientists involved in the flux modeling pilot need to understand and be focused on the needs of the climate policy and decision making community. If policy makers are to use CMS products, they must be aware of the modeling effort and begin to design policies that can be evaluated with information. Improving estimates of carbon sequestered in forests, for example, will require information on the spatial variability of forest biomass that is far more explicit than is presently possible using only ground observations. Carbon mitigation policies being implemented by cities around the United States could be designed with the CMS data in mind, enabling sequential evaluation and subsequent improvements in incentives, structures and programs. The success of climate mitigation programs being implemented in the United States today will hang on the depth of the relationship between scientists and their policy and decision making counterparts. Ensuring that there is two-way communication between data providers and users is important for the success both of the policies and the scientific products meant to support them..

  4. Description of real-time Ada software implementation of a power system monitor for the Space Station Freedom PMAD DC testbed

    NASA Technical Reports Server (NTRS)

    Ludwig, Kimberly; Mackin, Michael; Wright, Theodore

    1991-01-01

    The authors describe the Ada language software developed to perform the electrical power system monitoring functions for the NASA Lewis Research Center's Power Management and Distribution (PMAD) DC testbed. The results of the effort to implement this monitor are presented. The PMAD DC testbed is a reduced-scale prototype of the electric power system to be used in Space Station Freedom. The power is controlled by smart switches known as power control components (or switchgear). The power control components are currently coordinated by five Compaq 386/20e computers connected through an 802.4 local area network. The power system monitor algorithm comprises several functions, including periodic data acquisition, data smoothing, system performance analysis, and status reporting. Data are collected from the switchgear sensors every 100 ms, then passed through a 2-Hz digital filter. System performance analysis includes power interruption and overcurrent detection. The system monitor required a hardware timer interrupt to activate the data acquisition function. The execution time of the code was optimized by using an assembly language routine. The routine allows direct vectoring of the processor to Ada language procedures that perform periodic control activities.

  5. Dilution control in single-wire stainless steel submerged arc cladding

    SciTech Connect

    Kotecki, D.J.

    1996-02-01

    An experimental study of the effects of bead-to-bead stepover, wire size, wire feed speed, voltage, flux chromium content, and polarity on dilution and ferrite in single-wire submerged arc cladding of ER309L on mild steel plate is described. Low dilution was found to be promoted by reduced stepover, reduced wire feed speed, and DC electrode negative polarity. Use of a high-chromium flux can broaden the tolerance for dilution, providing an austenitic deposit free of martensite, and containing at least 4 FN for assurance of freedom from hot cracking over a broader range of dilutions.

  6. Orbiter Kapton wire operational requirements and experience

    NASA Technical Reports Server (NTRS)

    Peterson, R. V.

    1994-01-01

    The agenda of this presentation includes the Orbiter wire selection requirements, the Orbiter wire usage, fabrication and test requirements, typical wiring installations, Kapton wire experience, NASA Kapton wire testing, summary, and backup data.

  7. Observation of "wired" cell communication over 10-μm and 20-μm poly(dimethylsiloxane) barriers in tetracycline inducible expression systems

    NASA Astrophysics Data System (ADS)

    Kuo, Ching-Te; Chi, Cheng-Yu; Wu, Pei-Yi; Chuang, Fang-Tzu; Lin, Yueh-Chien; Liu, Hao-Kai; Huang, Guan-Syuan; Tsai, Tzu-Ching; Wo, Andrew M.; Lee, Hsinyu; Lee, Si-Chen

    2016-01-01

    Communication between cells and extracellular environments is of interest because of its critical roles in cell development and differentiation. Particularly, this signal transduction is commonly believed to rely on the contact and binding of the participating molecules/proteins, suggesting that the binding distance needed is less than a few nanometers. However, it is difficult to precisely match the rapidly binding interaction which depends on the probability of molecular collision in living systems, raising a hypothesis that another mechanism exists, could promote this signal communication, and remains unknown. Here we report that a long-range signal delivery over 10-μm and 20-μm polydimethylsiloxane (PDMS) barriers can be observed in microfluidically tetracycline (Tet) inducible expression systems. Results show that a significant increment of the long-range induced green fluorescent protein in human embryonic kidney 293T (HEK 293T) cells by the stimulation of Tet is demonstrated, and that such a signal induction is not dominated by Tet diffusion and displays a specific bindingless property. In addition, our experimental results, combined with theoretical modeling, suggest that this communication exhibits a bump-shaped characteristic depending on barrier thickness, materially structural property, surface roughness, and agonist concentration. It strongly relies on the PDMS barrier to delivery signal; therefore, we call such a mechanism as "wired" cell communication instead of wireless. These results could ignite interests in the novel and "wired" cell communication, which we call it X-signal, and in the use of such systems for the study of cellular biology and development of new drug.

  8. Investigation of factors affecting the heater wire method of calibrating fine wire thermocouples

    NASA Technical Reports Server (NTRS)

    Keshock, E. G.

    1972-01-01

    An analytical investigation was made of a transient method of calibrating fine wire thermocouples. The system consisted of a 10 mil diameter standard thermocouple (Pt, Pt-13% Rh) and an 0.8 mil diameter chromel-alumel thermocouple attached to a 20 mil diameter electrically heated platinum wire. The calibration procedure consisted of electrically heating the wire to approximately 2500 F within about a seven-second period in an environment approximating atmospheric conditions at 120,000 feet. Rapid periodic readout of the standard and fine wire thermocouple signals permitted a comparison of the two temperature indications. An analysis was performed which indicated that the temperature distortion at the heater wire produced by the thermocouple junctions appears to be of negligible magnitude. Consequently, the calibration technique appears to be basically sound, although several practical changes which appear desirable are presented and discussed. Additional investigation is warranted to evaluate radiation effects and transient response characteristics.

  9. A Swinging Wire.

    ERIC Educational Resources Information Center

    Auty, Geoff

    1993-01-01

    Outlines a safer alternative to the traditional physics demonstration known as the "kicking wire" experiment. The new method eliminates the use of an open dish of mercury but is less dramatic in the visible effects it produces. (DDR)

  10. Dual wire weld feed proportioner

    NASA Technical Reports Server (NTRS)

    Nugent, R. E.

    1968-01-01

    Dual feed mechanism enables proportioning of two different weld feed wires during automated TIG welding to produce a weld alloy deposit of the desired composition. The wires are fed into the weld simultaneously. The relative feed rates of the wires and the wire diameters determine the weld deposit composition.

  11. Dissipative Cryogenic Filters with Zero DC Resistance

    SciTech Connect

    Bluhm, Hendrik; Moler, Kathryn A.; /Stanford U., Appl. Phys. Dept

    2008-04-22

    The authors designed, implemented and tested cryogenic RF filters with zero DC resistance, based on wires with a superconducting core inside a resistive sheath. The superconducting core allows low frequency currents to pass with negligible dissipation. Signals above the cutoff frequency are dissipated in the resistive part due to their small skin depth. The filters consist of twisted wire pairs shielded with copper tape. Above approximately 1 GHz, the attenuation is exponential in {radical}{omega}, as typical for skin depth based RF filters. By using additional capacitors of 10 nF per line, an attenuation of at least 45 dB above 10 MHz can be obtained. Thus, one single filter stage kept at mixing chamber temperature in a dilution refrigerator is sufficient to attenuate room temperature black body radiation to levels corresponding to 10 mK above about 10 MHz.

  12. A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications

    PubMed Central

    Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

    2012-01-01

    This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters. PMID:23365536

  13. A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.

    PubMed

    Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

    2012-01-01

    This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters. PMID:23365536

  14. Operation of a test bed axial-gap brushless dc rotor with a superconducting stator

    SciTech Connect

    McKeever, J.W.; Sohns, C.W.; Schwenterly, S.W.; Young, R.W. Sr.; Campbell, V.W.; Hickey, M.H.; Ott, G.W.; Bailey, J.M.

    1993-08-01

    A variable-speed axial-gap motor with a stator consisting of four liquid helium cooled superconducting electromagnets (two pole pairs) was built and proof tested up to 608 rpm in November 1990 as a tool for joint industry-laboratory evaluation of coils fabricated from high-temperature oxide superconductors. A second rotor was fabricated with improved materia winding configuration, and wire type, and the drive system was modified to eliminate current spiking. The modified motor was characterized to design speed, 188 rad/s (1800 rpm), to acquire a performance baseline for future comparison with that of high-temperature superconducting (HIS) wire. As it becomes commercially available, HTS wire will replace the low-temperature electromagnet wire in a stator modified to control wire temperatures between 4 K and 77 K. Measurements of the superconducting electromagnetic field and locked rotor torque as functions of cryocurrent and dc current through two phases of the rotor, respectively, provided data to estimate power that could be developed by the rotor. Back emf and parasitic mechanical and electromagnetic drag torques were measured as functions of angular velocity to calculate actual rotor power developed and to quantify losses, which reduce the motor`s efficiency. A detailed measurement of motor power at design speed confirmed the developed power equation. When subsequently operated at the 33-A maximum available rotor current, the motor delivered 15.3 kill (20.5 hp) to the load. In a final test, the cryostat was operated at 2500 A, 200 A below its critical current. At rotor design current of 60 A and 2500 A stator current, the extrapolated developed power would be 44.2 kill (59.2 hp) with 94% efficiency.

  15. Composite ceramic superconducting wires for electric motor applications

    NASA Astrophysics Data System (ADS)

    Halloran, John W.

    1990-04-01

    Silver clad polycrystalline Y-123 wire is being fabricated with a continuous reel-to-reel process. Scale-up activities are underway to produce enough wire for the field coils of the HTSC motor. Green HTSC fiber were produced in kilometer lengths, and sintered wires up to 166 meters long. The 77K Jc values are 1000-2800 A/sq cm in self field. To improve Jc of the Y-123 wire, development began on directional crystallization, including preliminary work at A. D. Little and Oak Ridge National Lab. Large lots of BiSCCO material were produced to fabricated fibers and sintered polycrystalline BiSSCO wire as rolled tape. Work continued in collaboration with Sandia and Los Alamos National Laboratories on rapid thermal processing of Y-123, with most emphasis on characterizing the rapid oxygenation effect. The design of the HTSC homopolar motor has been improved to increase the output from field coils by using six smaller coils, each with separately optimized current. Motor construction is in progress. Preliminary design is underway on a dc heteropolar motor with HTSC field windings and armature and a brushless trapped flux permanent magnet dc motor, in which the field is produced by trapped flux in an HTSC rotor.

  16. Splicing Wires Permanently With Explosives

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Kushnick, Anne C.

    1990-01-01

    Explosive joining process developed to splice wires by enclosing and metallurgically bonding wires within copper sheets. Joints exhibit many desirable characteristics, 100-percent conductivity and strength, no heat-induced annealing, no susceptibility to corrosion in contacts between dissimilar metals, and stability at high temperature. Used to join wires to terminals, as well as to splice wires. Applicable to telecommunications industry, in which millions of small wires spliced annually.

  17. Needleless electrospinning with twisted wire spinneret.

    PubMed

    Holopainen, Jani; Penttinen, Toni; Santala, Eero; Ritala, Mikko

    2015-01-16

    A needleless electrospinning setup named 'Needleless Twisted Wire Electrospinning' was developed. The polymer solution is electrospun from the surface of a twisted wire set to a high voltage and collected on a cylindrical collector around the wire. Multiple Taylor cones are simultaneously self-formed on the downward flowing solution. The system is robust and simple with no moving parts aside from the syringe pump used to transport the solution to the top of the wire. The structure and process parameters of the setup and the results on the preparation of polyvinyl pyrrolidone (PVP), hydroxyapatite (HA) and bioglass fibers with the setup are presented. PVP fiber sheets with areas of 40 × 120 cm(2) and masses up to 1.15 g were prepared. High production rates of 5.23 g h(-1) and 1.40 g h(-1) were achieved for PVP and HA respectively. The major limiting factor of the setup is drying of the polymer solution on the wire during the electrospinning process which will eventually force to interrupt the process for cleaning of the wire. Possible solutions to this problem and other ways to develop the setup are discussed. The presented system provides a simple way to increase the production rate and area of fiber sheet as compared with the conventional needle electrospinning. PMID:25513842

  18. Needleless electrospinning with twisted wire spinneret

    NASA Astrophysics Data System (ADS)

    Holopainen, Jani; Penttinen, Toni; Santala, Eero; Ritala, Mikko

    2015-01-01

    A needleless electrospinning setup named ‘Needleless Twisted Wire Electrospinning’ was developed. The polymer solution is electrospun from the surface of a twisted wire set to a high voltage and collected on a cylindrical collector around the wire. Multiple Taylor cones are simultaneously self-formed on the downward flowing solution. The system is robust and simple with no moving parts aside from the syringe pump used to transport the solution to the top of the wire. The structure and process parameters of the setup and the results on the preparation of polyvinyl pyrrolidone (PVP), hydroxyapatite (HA) and bioglass fibers with the setup are presented. PVP fiber sheets with areas of 40 × 120 cm2 and masses up to 1.15 g were prepared. High production rates of 5.23 g h-1 and 1.40 g h-1 were achieved for PVP and HA respectively. The major limiting factor of the setup is drying of the polymer solution on the wire during the electrospinning process which will eventually force to interrupt the process for cleaning of the wire. Possible solutions to this problem and other ways to develop the setup are discussed. The presented system provides a simple way to increase the production rate and area of fiber sheet as compared with the conventional needle electrospinning.

  19. Giant dipole moment in a triad system. mechanisms of anisotropic photoresponse in the transient dc conductivity of dipolar solutes

    SciTech Connect

    Smirnov, S.N.; Braun, C.L.; Greenfield, S.R.; Svec, W.A.; Wasielewski, M.R.

    1996-07-25

    A transient dc conductivity method was used to observe formation of a giant dipole moment for the triad molecule MA-ANI-NI (ethoxyaniline-aminonaphthalimide-dimethylphenyl-naphthalenediimide-octyl) in toluene. The independence of the dipole moment on excitation wavelength indicates high efficiency of intramolecular energy or (and) electron transfer. The effect of light polarization on the DC conductivity signal caused by a photoinduced increase in solute dipole moment is considered in detail. It is shown that the time variation of the signal includes information about structural anomalies in the angular distribution function of molecular dipoles and depends on light polarization even for zero ground state dipole moment. Nonzero ground state dipole moment and (or) electric field dependence of the charge transfer rate constants give an additional source for an anisotropic photoresponse signal. Analysis of the photoresponse and its anisotropy for the triad gives ground ({mu}{sub g}), first ({mu}{sub l}), and second ({mu}{sub 2}) excited state dipole moments as follows: {mu}{sub g} = 12{+-}5 D, {mu}{sub l} = 35{+-}10, and {mu}{sub 2} = 87{+-}6 D. The lifetime of the giant dipole state is {tau} = 290{+-}10 ns, and the molecule`s rotational time is {tau}{sub r} = 1.6{+-}0.15 ns. 14 refs., 7 figs., 2 tabs.

  20. Problems with aging wiring in Naval aircraft

    NASA Technical Reports Server (NTRS)

    Campbell, Frank J.

    1994-01-01

    The Navy is experiencing a severe aircraft electrical wiring maintenance problem as a result of the extensive use of an aromatic polyimide insulation that is deteriorating at a rate that was unexpected when this wire was initially selected. This problem has significantly affected readiness, reliability, and safety and has greatly increased the cost of ownership of Naval aircraft. Failures in wire harnesses have exhibited arcing and burning that will propagate drastically, to the interruption of many electrical circuits from a fault initiated by the failure of deteriorating wires. There is an urgent need for a capability to schedule aircraft rewiring in an orderly manner with a logically derived determination of which aircraft have aged to the point of absolute necessity. Excessive maintenance was demonstrated to result from the accelerated aging due to the parameters of moisture, temperature, and strain that exist in the Naval Aircraft environment. Laboratory studies have demonstrated that MIL-W-81381 wire insulation when aged at high humidities followed the classical Arrhenius thermal aging relationship. In an extension of the project a multifactor formula was developed that is now capable of predicting life under varying conditions of these service parameters. An automated test system has also been developed to analyze the degree of deterioration that has occurred in wires taken from an aircraft in order to obtain an assessment of remaining life. Since it is both physically and financially impossible to replace the wiring in all the Navy's aircraft at once, this system will permit expedient scheduling so that those aircraft that are most probable to have wiring failure problems can be overhauled first.

  1. Switchable optical transmittance of TiO2 submicron-diameter wire suspension-based "smart window" device

    NASA Astrophysics Data System (ADS)

    Leinberg, S.; Kisand, V.; Šutka, A.; Saal, K.; Lõhmus, R.; Joost, U.; Timusk, M.; Nõmmiste, E.

    2015-08-01

    In this paper, for the first time, a TiO2 submicron-diameter wire suspension-based smart window device is demonstrated in which combined planar and finger electrodes are utilised to reversibly change the orientation of the nanowires. Electrospun TiO2 anatase submicron-diameter wire suspensions in a viscous polydimethylsiloxane (PDMS) matrix were prepared directly from electrospun submicron-diameter fibre mats by using high-shear mixing, achieving the complete break-up of all electrospun mats and suspending TiO2 submicron-diameter wires uniformly in the PDMS matrix. Suspension was used as an active layer in an electro-optical device where a reversible change in light scattering is achieved by preparing a device consisting of an active layer and combined planar and finger electrode system. Using the constructed device, it was possible to change the alignment or spatial distribution of TiO2 submicron-diameter wires by applying a DC electric field across the planar or finger, electrodes thus changing the transmittance (ΔT = 25%) of the suspension and demonstrating the potential to use combined planar and finger electrode devices in smart window applications.

  2. Development of lightning-resistant overhead ground wire

    SciTech Connect

    Yokoya, Munehisa; Katsuragi, Yukio ); Goda, Yutaka ); Nagata, Yutaka; Asano, Yuji )

    1994-07-01

    Overhead ground wires (GW) are vulnerable to strand breakage due to lightning strikes. With the wider application in recent years of Composite Fiber Optic Ground Wire (OPGW), it becomes more important to protect GW from such damage. In this paper, the authors present the results of various investigations made in developing lightning-resistant GW/OPGW. Investigations included field experiments using rocket-triggered lightning, studies on materials and designs to improve lightning characteristics and various evaluation tests, such as DC arc tests, of several prototypes. As a result, the authors have developed excellent lightning-resistant GW/OPGW applicable for conventional transmission lines.

  3. DEVELOPMENT OF DROPLET SIZING FOR THE EVALUATION OF SCRUBBING SYSTEMS

    EPA Science Inventory

    The report describes the development and characteristics of the DC-2 Droplet Counter as used to evaluate scrubbing systems. The measurement of entrained droplets and their concentrations in gas streams is important in pollution control technology. The use of a hot-wire sensor can...

  4. Description of real-time Ada software implementation of a power system monitor for the Space Station Freedom PMAD DC testbed

    NASA Technical Reports Server (NTRS)

    Ludwig, Kimberly; Mackin, Michael; Wright, Theodore

    1991-01-01

    The Ada language software development to perform the electrical system monitoring functions for the NASA Lewis Research Center's Power Management and Distribution (PMAD) DC testbed is described. The results of the effort to implement this monitor are presented. The PMAD DC testbed is a reduced-scale prototype of the electrical power system to be used in the Space Station Freedom. The power is controlled by smart switches known as power control components (or switchgear). The power control components are currently coordinated by five Compaq 382/20e computers connected through an 802.4 local area network. One of these computers is designated as the control node with the other four acting as subsidiary controllers. The subsidiary controllers are connected to the power control components with a Mil-Std-1553 network. An operator interface is supplied by adding a sixth computer. The power system monitor algorithm is comprised of several functions including: periodic data acquisition, data smoothing, system performance analysis, and status reporting. Data is collected from the switchgear sensors every 100 milliseconds, then passed through a 2 Hz digital filter. System performance analysis includes power interruption and overcurrent detection. The reporting mechanism notifies an operator of any abnormalities in the system. Once per second, the system monitor provides data to the control node for further processing, such as state estimation. The system monitor required a hardware time interrupt to activate the data acquisition function. The execution time of the code was optimized using an assembly language routine. The routine allows direct vectoring of the processor to Ada language procedures that perform periodic control activities. A summary of the advantages and side effects of this technique are discussed.

  5. DC-to-DC switching converter

    NASA Technical Reports Server (NTRS)

    Cuk, Slobodan M. (Inventor); Middlebrook, Robert D. (Inventor)

    1980-01-01

    A dc-to-dc converter having nonpulsating input and output current uses two inductances, one in series with the input source, the other in series with the output load. An electrical energy transferring device with storage, namely storage capacitance, is used with suitable switching means between the inductances to DC level conversion. For isolation between the source and load, the capacitance may be divided into two capacitors coupled by a transformer, and for reducing ripple, the inductances may be coupled. With proper design of the coupling between the inductances, the current ripple can be reduced to zero at either the input or the output, or the reduction achievable in that way may be divided between the input and output.

  6. Radiation Effects on DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2001-01-01

    In this work, several DC-DC converters were designed and built. The converters are Buck Buck-Boost, Cuk, Flyback, and full-bridge zero-voltage switched. The total ionizing dose radiation and single event effects on the converters were investigated. The experimental results for the TID effects tests show that the voltages of the Buck Buck-Boost, Cuk, and Flyback converters increase as total dose increased when using power MOSFET IRF250 as a switching transistor. The change in output voltage with total dose is highest for the Buck converter and the lowest for Flyback converter. The trend of increase in output voltages with total dose in the present work agrees with those of the literature. The trends of the experimental results also agree with those obtained from PSPICE simulation. For the full-bridge zero-voltage switch converter, it was observed that the dc-dc converter with IRF250 power MOSFET did not show a significant change of output voltage with total dose. In addition, for the dc-dc converter with FSF254R4 radiation-hardened power MOSFET, the output voltage did not change significantly with total dose. The experimental results were confirmed by PSPICE simulation that showed that FB-ZVS converter with IRF250 power MOSFET's was not affected with the increase in total ionizing dose. Single Event Effects (SEE) radiation tests were performed on FB-ZVS converters. It was observed that the FB-ZVS converter with the IRF250 power MOSFET, when the device was irradiated with Krypton ion with ion-energy of 150 MeV and LET of 41.3 MeV-square cm/mg, the output voltage increased with the increase in fluence. However, for Krypton with ion-energy of 600 MeV and LET of 33.65 MeV-square cm/mg, and two out of four transistors of the converter were permanently damaged. The dc-dc converter with FSF254R4 radiation hardened power MOSFET's did not show significant change at the output voltage with fluence while being irradiated by Krypton with ion energy of 1.20 GeV and LET of 25.97 MeV-square cm/mg. This might be due to fact that the device is radiation hardened.

  7. Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2000-01-01

    DC/DC converters that are capable of operating at cryogenic temperatures are anticipated to play an important role in the power systems of future NASA deep space missions. Design of these converters to survive cryogenic temperatures will improve the power system performance, and reduce development and launch costs. At the NASA Glenn Research Center Low Temperature Electronics Laboratory, several commercial off-the-shelf dc/dc converter modules were evaluated for their low temperature performance. Various parameters were investigated as a function of temperature, in the range of 20 C to -190 C. Data pertaining to the efficiency and voltage regulation of the tested converters is presented and discussed.

  8. Analysis of payload bay magnetic fields due to dc power multipoint and single point ground configurations

    NASA Technical Reports Server (NTRS)

    Lawton, R. M.

    1976-01-01

    An analysis of magnetic fields in the Orbiter Payload Bay resulting from the present grounding configuration (structure return) was presented and the amount of improvement that would result from installing wire returns for the three dc power buses was determined. Ac and dc magnetic fields at five points in a cross-section of the bay are calculated for both grounding configurations. Y and Z components of the field at each point are derived in terms of a constant coefficient and the current amplitude of each bus. The dc loads assumed are 100 Amperes for each bus. The ac noise current used is a spectrum 6 db higher than the Orbiter equipment limit for narrowband conducted emissions. It was concluded that installing return wiring to provide a single point ground for the dc Buses in the Payload Bay would reduce the ac and dc magnetic field intensity by approximately 30 db.

  9. Modelling and Simulation of Digital Compensation Technique for dc-dc Converter by Pole Placement

    NASA Astrophysics Data System (ADS)

    Shenbagalakshmi, R.; Sree Renga Raja, T.

    2015-09-01

    A thorough and effective analysis of the dc-dc converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modelling based on state space averaging technique for dc-dc converters is carried out. A digital state feedback gain matrix is derived by pole placement technique in order to achieve the stability of a completely controllable system. A prediction observer for the dc-dc converters is designed and a dynamic compensation (observer plus control law) is provided using separation principle. The output is very much improved with zero output voltage ripples, zero peak overshoot, and much lesser settling time in the range of ms and with higher overall efficiency (>90 %).

  10. Test Results of Selected Commercial DC/DC Converters under Cryogenic Temperatures - A Digest

    NASA Technical Reports Server (NTRS)

    Patterson, Richard; Hammoud, Ahmad

    2010-01-01

    DC/DC converters are widely used in space power systems in the areas of power management and distribution, signal conditioning, and motor control. Design of DC/DC converters to survive cryogenic temperatures will improve the power system performance, simplify design, and reduce development and launch costs. In this work, the performance of nine COTS modular, low-tomedium power DC/DC converters was investigated under cryogenic temperatures. The converters were evaluated in terms of their output regulation, efficiency, and input and output currents. At a given temperature, these properties were obtained at various input voltages and at different load levels. A summary on the performance of the tested converters was given. More comprehensive testing and in-depth analysis of performance under long-term exposure to extreme temperatures are deemed necessary to establish the suitability of these and other devices for use in the harsh environment of space exploration missions.

  11. Wiring up, reaching out.

    PubMed

    Serb, C

    1999-05-01

    Taking another step in our Most Wired project, we conducted cyber-interviews with health plans and asked them to tell us just how wired they are. Find out how well they connect to members and employers, which HR and educational services they offer online, and whether they do business with doctors and hospitals electronically. Plus: profiles of major info tech undertakings at six health plans. They range from a $78,000 intranet to a $4 million data warehouse. But while the six projects differ in cost, they overlap in purpose: putting more information into the hands of doctors, hospitals, employers, and consumers. In doing that, they show what being wired is all about. PMID:10404661

  12. Wire brush fastening device

    DOEpatents

    Meigs, R.A.

    1995-09-19

    A fastening device is provided which is a variation on the conventional nut and bolt. The bolt has a longitudinal axis and threading helically affixed thereon along the longitudinal axis. A nut having a bore extending therethrough is provided. The bore of the nut has a greater diameter than the diameter of the bolt so the bolt can extend through the bore. An array of wire bristles are affixed within the bore so as to form a brush. The wire bristles extend inwardly from the bore and are constructed and arranged of the correct size, length and stiffness to guide the bolt within the bore and to restrain the bolt within the bore as required. A variety of applications of the wire brush nut are disclosed, including a bolt capture device and a test rig apparatus. 13 figs.

  13. Wire brush fastening device

    DOEpatents

    Meigs, Richard A.

    1995-01-01

    A fastening device is provided which is a variation on the conventional nut and bolt. The bolt has a longitudinal axis and threading helically affixed thereon along the longitudinal axis. A nut having a bore extending therethrough is provided. The bore of the nut has a greater diameter than the diameter of the bolt so the bolt can extend through the bore. An array of wire bristles are affixed within the bore so as to form a brush. The wire bristles extend inwardly from the bore and are constructed and arranged of the correct size, length and stiffness to guide the bolt within the bore and to restrain the bolt within the bore as required. A variety of applications of the wire brush nut are disclosed, including a bolt capture device and a test rig apparatus.

  14. Third NASA Workshop on Wiring for Space Applications

    SciTech Connect

    Hammoud, A.; Stavnes, M.

    1995-11-01

    This workshop addressed key technology issues in the field of electrical power wiring for space applications, and transferred information and technology related to space wiring for use in government and commercial applications. Speakers from space agencies, U.S. Federal labs, industry, and academia presented program overviews and discussed topics on arc tracking phenomena, advancements in insulation materials and constructions, and new wiring system topologies. A separate abstract has been prepared for one article from this workshop.

  15. Third NASA Workshop on Wiring for Space Applications

    NASA Technical Reports Server (NTRS)

    Hammoud, Ahmad (Compiler); Stavnes, Mark (Compiler)

    1995-01-01

    This workshop addressed key technology issues in the field of electrical power wiring for space applications, and transferred information and technology related to space wiring for use in government and commercial applications. Speakers from space agencies, U.S. Federal labs, industry, and academia presented program overviews and discussed topics on arc tracking phenomena, advancements in insulation materials and constructions, and new wiring system topologies.

  16. Programmable dc motor controller

    SciTech Connect

    Hopwood, J.E.

    1982-11-01

    A portable programmable dc motor controller, with features not available on commercial instruments, was developed at Sandia National Laboratories, Livermore, for controlling fixtures during welding processes. The controller can be used to drive any dc motor having tachometer feedback and moter requirements not exceeding 30 volts, 3 amperes. Among the controller's features are delayed start time, upslope time, speed, and downslope time.

  17. Beam profile measurement with flying wires at the Fermilab Recycler Ring

    SciTech Connect

    Carcagno, R.; Pishchalnikov, Yu.; Krider, J.; Hu, M.; Lorman, E.; Marchionni, A.; Pordes, S.; Wilson, P.; Zagel, J.; /Fermilab

    2005-05-01

    Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement for both proton and antiproton beams. The following note describes the system configuration, calibration and resolution of the flying wire system, interactions between the wires and the beam, as well as analysis of the transverse beam profile in the presence of a stochastic cooling system.

  18. Multilevel DC link inverter

    DOEpatents

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  19. An open-source, FireWire camera-based, Labview-controlled image acquisition system for automated, dynamic pupillometry and blink detection.

    PubMed

    de Souza, John Kennedy Schettino; Pinto, Marcos Antonio da Silva; Vieira, Pedro Gabrielle; Baron, Jerome; Tierra-Criollo, Carlos Julio

    2013-12-01

    The dynamic, accurate measurement of pupil size is extremely valuable for studying a large number of neuronal functions and dysfunctions. Despite tremendous and well-documented progress in image processing techniques for estimating pupil parameters, comparatively little work has been reported on practical hardware issues involved in designing image acquisition systems for pupil analysis. Here, we describe and validate the basic features of such a system which is based on a relatively compact, off-the-shelf, low-cost FireWire digital camera. We successfully implemented two configurable modes of video record: a continuous mode and an event-triggered mode. The interoperability of the whole system is guaranteed by a set of modular software components hosted on a personal computer and written in Labview. An offline analysis suite of image processing algorithms for automatically estimating pupillary and eyelid parameters were assessed using data obtained in human subjects. Our benchmark results show that such measurements can be done in a temporally precise way at a sampling frequency of up to 120 Hz and with an estimated maximum spatial resolution of 0.03 mm. Our software is made available free of charge to the scientific community, allowing end users to either use the software as is or modify it to suit their own needs. PMID:23993408

  20. High power density dc/dc converter: Selection of converter topology

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; and Three Phase Dual Active Bridges DC/DC Converter (Topology C). The salient features of these topologies are: (1) All are minimal in structure, i.e., each consists of an input and output bridge, input and output filter and a transformer, all components essential for a high power dc/dc conversion process; (2) All devices of both the bridges can operate under near zero-voltage conditions, making possible a reduction of device switching losses and hence, an increase in switching frequency; (3) All circuits operate at a constant frequency, thus simplifying the task of the magnetic and filter elements; (4) Since, the leakage inductance of the transformer is used as the main current transfer element, problems associated with the diode reverse recovery are eliminated. Also, this mode of operation allows easy paralleling of multiple modules for extending the power capacity of the system; (5) All circuits are least sensitive to parasitic impedances, infact the parasitics are efficently utilized; and (6) The soft switching transitions, result in low electromagnetic interference. A detailed analysis of each topology was carried out. Based on the analysis, the various device and component ratings for each topology operating at an optimum point, and under the given specifications, are tabulated and discussed.

  1. RF-to-DC Characteristics of Direct Irradiated On-Chip Gallium Arsenide Schottky Diode and Antenna for Application in Proximity Communication System

    PubMed Central

    Mustafa, Farahiyah; Hashim, Abdul Manaf

    2014-01-01

    We report the RF-to-DC characteristics of the integrated AlGaAs/GaAs Schottky diode and antenna under the direct injection and irradiation condition. The conversion efficiency up to 80% under direct injection of 1 GHz signal to the diode was achieved. It was found that the reduction of series resistance and parallel connection of diode and load tend to lead to the improvement of RF-to-DC conversion efficiency. Under direct irradiation from antenna-to-antenna method, the output voltage of 35 mV was still obtainable for the distance of 8 cm between both antennas in spite of large mismatch in the resonant frequency between the diode and the connected antenna. Higher output voltage in volt range is expected to be achievable for the well-matching condition. The proposed on-chip AlGaAs/GaAs HEMT Schottky diode and antenna seems to be a promising candidate to be used for application in proximity communication system as a wireless low power source as well as a highly sensitive RF detector. PMID:24561400

  2. Use of a Nonequilibrium MHD Generator for Conversion of SNTP Nuclear Thermal Rocket Exhaust to DC Electric Power for a Multimegawatt Nuclear Electric Propulsion System

    NASA Astrophysics Data System (ADS)

    Finley, Charles J.

    1994-07-01

    This paper explores a method by which the energy of a high speed flowing gas can efficiently be converted into DC electric power by a magnetohydrodynamic (MHD) generator. A nonequilibrium state may be created in the working fluid during the ionization process using an arc discharge. This nonequilibrium state may possibly be sustained in the fluid using the waste heat byproduct of the natural operation of the generator, if certain characteristics of the fluid/MHD system are maintained. The improved efficiency of the resulting nonequilibrium MHD generator not only allows the system to deliver increased power to the load, but reduces the amount of energy to be expelled from the closed fluid cycle by a radiator.

  3. Static DC to DC Power Conditioning-Active Ripple Filter, 1 MHZ DC to DC Conversion, and Nonlinear Analysis. Ph.D. Thesis; [voltage regulation and conversion circuitry for spacecraft power supplies

    NASA Technical Reports Server (NTRS)

    Sander, W. A., III

    1973-01-01

    Dc to dc static power conditioning systems on unmanned spacecraft have as their inputs highly fluctuating dc voltages which they condition to regulated dc voltages. These input voltages may be less than or greater than the desired regulated voltages. The design of two circuits which address specific problems in the design of these power conditioning systems and a nonlinear analysis of one of the circuits are discussed. The first circuit design is for a nondissipative active ripple filter which uses an operational amplifier to amplify and cancel the sensed ripple voltage. A dc to dc converter operating at a switching frequency of 1 MHz is the second circuit discussed. A nonlinear analysis of the type of dc to dc converter utilized in designing the 1 MHz converter is included.

  4. Bacillus cereus AR156 Extracellular Polysaccharides Served as a Novel Micro-associated Molecular Pattern to Induced Systemic Immunity to Pst DC3000 in Arabidopsis

    PubMed Central

    Jiang, Chun-Hao; Fan, Zhi-Hang; Xie, Ping; Guo, Jian-Hua

    2016-01-01

    Non-host resistance (NHR) is a broad-spectrum plant defense. Upon colonizing on the surface on the root or leaves of non-host species, pathogens initial encounter preform and induce defense response in plant, such as induced hypersensitive response, PAMPs triggered immunity (PTI), and effector triggered immunity (ETI). The ability of plants to develop an induced systemic response (ISR) in reaction to the colonization by non-pathogenic rhizobacterium depends on interactions between host plants and the colonizing rhizobacterium, and the ISR also can be defined as a NHR. However, how the colonization signal is and how systemic resistance to pathogens is developed is still unclear. In this study, we demonstrated that the extracellular polysaccharides (EPSs) of Bacillus cereus AR156 could act as novel microbe-associated molecular patterns (MAMPs) and function in the early perception status of the ISR of B. cereus AR156. The results revealed that B. cereus AR156 EPS could induce systemic resistance to Pst DC3000 in Arabidopsis. Cellular defense response markers such as hydrogen peroxide accumulation, callose deposition, and defense-associated enzyme were induced upon challenge inoculation in the leaves primed by EPS. Moreover, the defense-related genes PR1, PR2, and PR5 and mitogen-activated kinases (MAPK) cascade marker gene MPK6 were concurrently expressed in the leaves of EPS-treated plants and induced higher resistance to Pst DC3000 in Col-0 than that in the jar1 or etr1 mutants. The protection was absent in the NahG transgenic plants and npr1 mutant, suggesting an activation of the salicylic acid (SA)- and the MAPK-dependent signaling pathways with NPR1-dependent by B. cereus AR156 EPS. In conclusion, B. cereus AR156 EPS play an important role in MAMP perception during the process of rhizobacteria-triggered NHR. This study is the first to illustrate how AR156 induces systemic resistance to Pst DC3000 in Arabidopsis. It also provides the first explanation of how plants perceive colonization of non-pathogenic bacteria and how rhizobacteria trigger ISR to plant pathogens.

  5. Data acquisition system development for the detection of X-ray photons in multi-wire gas proportional counters

    NASA Astrophysics Data System (ADS)

    Kimpton, J. A.; Kinnane, M. N.; Smale, L. F.; Chantler, C. T.; Hudson, L. T.; Henins, A.; Szabo, C. I.; Gillaspy, J. D.; Tan, J. N.; Pomeroy, J. M.; Takacs, E.; Radics, B.

    2007-09-01

    A new data acquisition system coupled to a backgammon-type gas proportional counter capable of single-photon counting over a wide range of count rates has been developed and replaces a CAMAC-based system. The new apparatus possesses improved architecture, interface technology, speed and diagnostic capability. System efficiency and throughput is significantly improved, especially in addressing earlier problems of hardware buffer downloads containing zero or repeat data and inefficient gating control. The new system is a PXI-based data acquisition apparatus including additional electronics, controlled by a graphical programming environment. It allows development of superior diagnostic tools for system optimisation and more stable performance. System efficiency is improved by 10% over a wide range of count rates (0.5 Hz-50 kHz). For the Backgammon Detector type, this represents a significant improvement in performance and applicability over previous systems. Characteristic and few-electron spectra collected on the new acquisition system are illustrated.

  6. Transition from tunneling to hopping transport in long, conjugated oligo-imine wires connected to metals.

    PubMed

    Choi, Seong Ho; Risko, Chad; Delgado, M Carmen Ruiz; Kim, Bongsoo; Brédas, Jean-Luc; Frisbie, C Daniel

    2010-03-31

    We report the electrical transport characteristics of conjugated oligonaphthalenefluoreneimine (ONI) wires having systematically varied lengths up to 10 nm. Using aryl imine addition chemistry, ONI wires were built from gold substrates by extending the conjugation length through imine linkages between highly conjugated building blocks of alternating naphthalenes and fluorenes. The resistance and current-voltage characteristics of ONI wires were measured as a function of molecular length, temperature, and electric field using conducting probe atomic force microscopy (CP-AFM). We have observed a transition in direct current (DC) transport from tunneling to hopping near 4 nm as previously established for oligophenyleneimine (OPI) wires. Furthermore, we have found that long ONI wires are less resistive than OPI wires. The single-wire conductivity of ONI wires is approximately 1.8 +/- 0.1 x 10(-4) S/cm, a factor of approximately 2 greater than that of OPI wires, and consistent with the lower transport activation energy ( approximately 0.58 eV versus 0.65 eV or 13 versus 15 kcal/mol). Quantum chemical calculations reveal that charge is preferentially localized on the fluorene subunits and that the molecules are substantially twisted. Overall, this work confirms that imine addition chemistry can be used to build molecular wires long enough to probe the hopping transport regime. The versatility of this chemistry, in combination with CP-AFM, opens up substantial opportunities to probe the physical organic chemistry of hopping conduction in long conjugated molecules. PMID:20218660

  7. The Fiscal Impact of the D.C. Voucher Program

    ERIC Educational Resources Information Center

    Aud, Susan L.; Michos, Leon

    2006-01-01

    In August 2004 the first ever federally funded school voucher program began in Washington, D.C. Eligible students could attend a private school of their choice in the District of Columbia. Each participant received up to $7,500 for school tuition, fees, and transportation. In addition, the D.C. Public School System (DCPS) and D.C. charter school…

  8. Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

    NASA Astrophysics Data System (ADS)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.

    1980-04-01

    The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

  9. Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.

    1980-01-01

    The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

  10. Caroviologens: Towards molecular wires

    NASA Astrophysics Data System (ADS)

    Blanchard-Desce, M.; Arrhenius, T. S.; Dvolaïtzky, M.; Kugimiya, S.-I.; Lazrak, T.; Lehn, J.-M.

    1992-07-01

    Bispyridinium conjugated polyenes of different lengths and charges have been synthesized. Since they combine the features of carotenoids and of viologens, they have been termed caroviologens. Such molecules, possessing an extended conjugated chain fitted with polar electroactive endgroups, and having a length sufficient to span a lipid membrane could function as transmembrane electron channels, i.e., as molecular wires.

  11. Debate: Wired versus Wireless.

    ERIC Educational Resources Information Center

    Meeks, Glenn; Nair, Prakash

    2000-01-01

    Debates the issue of investing in wiring schools for desktop computer networks versus using laptops and wireless networks. Included are cost considerations and the value of technology for learning. Suggestions include using wireless networks for existing schools, hardwiring computers for new construction, and not using computers for elementary…

  12. Reliable Wiring Harness

    NASA Technical Reports Server (NTRS)

    Gaspar, Kenneth C.

    1987-01-01

    New harness for electrical wiring includes plugs that do not loosen from vibration. Ground braids prevented from detaching from connectors and constrained so braids do not open into swollen "birdcage" sections. Spring of stainless steel encircles ground braid. Self-locking connector contains ratchet not only preventing connector from opening, but tightens when vibrated.

  13. Improved wire chamber

    DOEpatents

    Atac, M.

    1987-05-12

    An improved gas mixture for use with proportional counter devices, such as Geiger-Mueller tubes and drift chambers. The improved gas mixture provides a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor. 2 figs.

  14. A World without Wires

    ERIC Educational Resources Information Center

    Panettieri, Joseph C.

    2006-01-01

    The wireless bandwagon is rolling across Mississippi, picking up a fresh load of converts and turning calamity into opportunity. Traditional wired school networks, many of which unraveled during Hurricane Katrina, are giving way to advanced wireless mesh networks that frequently include voice-over-IP (VoIP) capabilities. Vendor funding is helping…

  15. Residential Wiring. Second Edition.

    ERIC Educational Resources Information Center

    Taylor, Mark; And Others

    This guide is designed to assist teachers conducting a course to prepare students for entry-level employment in the residential wiring trade. Included in the guide are six instructional units and the following sections of information for teachers: guidelines in using the unit components; academic and workplace skills classifications and…

  16. NewsWire, 2002.

    ERIC Educational Resources Information Center

    Byrom, Elizabeth, Ed.; Bingham, Margaret, Ed.; Bowman, Gloria, Ed.; Shoemaker, Dan, Ed.

    2002-01-01

    This document presents the 3 2002 issues of the newsletter "NewsWire," (volume 5). Issue Number One focuses on collaborative Web projects. This issue begins with descriptions of four individual projects: "iEARN"; "Operation RubyThroat"; "Follow the Polar Huskies!"; and "Log in Your Animal Roadkill!" Features that follow include: "Bringing the…

  17. Basic Wiring. Second Edition.

    ERIC Educational Resources Information Center

    Kaltwasser, Stan; And Others

    This guide is designed to assist teachers conducting a foundation course to prepare students for additional courses of training for entry-level employment in either the residential or commercial and industrial wiring trades. Included in the guide are 17 instructional units and the following sections of information for teachers: guidelines in using…

  18. Wire EDM for Refractory Materials

    NASA Technical Reports Server (NTRS)

    Zellars, G. R.; Harris, F. E.; Lowell, C. E.; Pollman, W. M.; Rys, V. J.; Wills, R. J.

    1982-01-01

    In an attempt to reduce fabrication time and costs, Wire Electrical Discharge Machine (Wire EDM) method was investigated as tool for fabricating matched blade roots and disk slots. Eight high-strength nickel-base superalloys were used. Computer-controlled Wire EDM technique provided high quality surfaces with excellent dimensional tolerances. Wire EDM method offers potential for substantial reductions in fabrication costs for "hard to machine" alloys and electrically conductive materials in specific high-precision applications.

  19. Data Resources and Services at CAsDC

    NASA Astrophysics Data System (ADS)

    Cui, Chenzhou; He, Boliang; Xiao, Jian; Yu, Ce; Li, Jian; Cao, Zihuang; Su, Liying; Fan, Dongwei; Qiao, Cuilan; Li, Changhua; Chen, Yue; Wang, Runtao; Zhao, Yongheng

    2014-01-01

    The Chinese Astronomical Data Center (CAsDC) is a member of World Data System, hosted at National Astronomical Observatories, Chinese Academy of Sciences(NAOC). The CAsDC keeps close collaboration with IVOA, WDS and CODATA. The whole set of LAMOST data, including raw data and data products, are hosted at the CAsDC. Data resources and services of the CAsDC are introduced.

  20. 49 CFR 234.231 - Fouling wires.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Fouling wires. 234.231 Section 234.231 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Maintenance,...