These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Topology for Current Balancer with Half-Bridge Inverters in Single-Phase Three-Wire Distribution Systems with DC-Capacitor-Voltage Balancer  

NASA Astrophysics Data System (ADS)

This paper proposes a new topology for a current balancer with half-bridge inverters in single-phase three-wire distribution systems with a three-leg inverter. Two half-bridge inverters are connected to the sources. The midpoint of two capacitors on the DC-side is connected to a neutral line. The two half-bridge inverters perform a current balancer for single-phase three-wire distribution systems by exchanging the active and reactive power on the each feeder through the two DC-capacitors. The third-leg performs a DC-capacitor-voltage balancer for the two DC-capacitors connected to the half-bridge inverters. Thus, balanced source voltages and currents are obtained on the secondary-side on the pole-mounted distribution transformer with balanced DC-capacitor voltages. The basic principle of the proposed current balancer is discussed in detail, and then, confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results show that balanced source voltages and currents are obtained on the secondary-side on the pole-mounted distribution transformer with balanced DC-capacitor voltages.

Baba, Yusuke; Sugahara, Kazuya; Okamoto, Masayuki; Hiraki, Eiji; Tanaka, Toshihiko

2

A novel four-branches-inverter-based-active-filter for harmonic suppression and reactive compensation of an unbalanced three-phase four-wires electrical distribution systems, feeding AC\\/DC loads  

Microsoft Academic Search

This paper deals with the design, analysis and digital simulation of a novel four-branches-inverter-based-active-filter, that compensates the reactive power and suppress the harmonic currents in the phases and neutral of an unbalanced three-phase four-wires electrical distribution system, feeding AC\\/DC loads. That is, the filter has the capability to instantaneously suppress the harmonics currents, in both the three-phases and the neutral,

Alfredo Nava-Segura; G. Mino-Aguilar

2000-01-01

3

LANSCE-R WIRE-SCANNER SYSTEM  

SciTech Connect

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.

Gruchalla, Michael E. [Los Alamos National Laboratory

2011-01-01

4

A 37 channel DC SQUID magnetometer system  

Microsoft Academic Search

A 37-channel DC SQUID magnetometer system has been built for biomagnetic studies. The SQUID loop of each magnetometer serves as the active sensing element, thereby eliminating the need for flux coupling circuits. The magnetometers are located ≃3 cm above the outer dewar bottom. The SQUIDs are directly coupled to a highly simplified readout electronics using only five wires per channel;

H. Koch; R. Cantor; D. Drung; S. N. Erne; K. P. Matthies; M. Peters; T. Ryhanen; H. J. Scheer; H. D. Hahlbohm

1991-01-01

5

49 CFR 393.28 - Wiring systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Wiring systems. 393.28 Section 393.28 Transportation Other Regulations Relating to...Lamps, Reflective Devices, and Electrical Wiring § 393.28 Wiring systems. Electrical wiring...

2010-10-01

6

Control of the Neutral Point in Four-Wire Three-Phase DC–AC Converters  

Microsoft Academic Search

Inverters used as the interface for a distributed generator in a three-phase four-wire system sometimes operate with a large neutral current because of unbalanced loads and single-phase (possibly nonlinear) loads. Voltage balance within the dc-link of the inverter is important for proper operation of the inverter, and the neutral current is a significant disturbance to this. It is preferable to

Q.-C. Zhong; J. Liang; G. Weiss; Chunmei Feng; Timothy C. Green

2006-01-01

7

DC/AC Student Guide: Wire Cable Characteristics  

NSDL National Science Digital Library

The purpose of this lab is to collect data on measurements, observe skin effect in wires and propagation delay in a cable, and summarize your findings. This pdf contains the student guide for this lesson including the equipment needed, learning objectives, a detailed procedure, and all other information necessary for the lab.

Phillips, Wayne

2014-07-30

8

Ultracapacitors + DC-DC converters in regenerative braking system  

Microsoft Academic Search

An ultracapacitor system for an electric vehicle has been implemented. The device allows higher accelerations and decelerations of the vehicle with minimal loss of energy and minimal degradation of the main battery pack. The system uses a DC-DC power converter, which is connected between the ultracapacitor and the main battery pack. The design has been optimized in weight and size,

J. W. Dixon; M. E. Ortuzar

2002-01-01

9

SpaceWire Data Handling Demonstration System  

NASA Astrophysics Data System (ADS)

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.

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

2007-08-01

10

Length-dependent oscillations in the dc conductance of laser-driven quantum wires  

NASA Astrophysics Data System (ADS)

We calculate the dc conductance at zero temperature of clean quantum wires driven by a laser field. In the high-frequency regime we find an interplay between length-dependent interference effects and dynamical localization, which leads to a modulation by a Bessel function of the even-odd oscillations in the conductance. In the low-frequency regime we find that the field suppresses these oscillations. We present some analytical expressions for each of these frequency limits.

Martinez, D. F.; Molina, R. A.; Hu, Bambi

2008-07-01

11

A Vibrating Wire System For Quadrupole Fiducialization  

SciTech Connect

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.

Wolf, Zachary

2010-12-13

12

29 CFR 1926.404 - Wiring design and protection.  

Code of Federal Regulations, 2010 CFR

...Service-entrance conductors installed as open wires shall be guarded to make them accessible...wiring shall be grounded: (i) Three-wire DC systems. All 3-wire DC systems...nominally rated 480Y/277 volt, 3-phase, 4-wire in which the neutral is used...

2010-07-01

13

DC-DC converter design for battery-operated systems  

Microsoft Academic Search

This paper describes performance, design and optimization of DC-DC converters for energy limited, battery operated systems. Variable-frequency operation is used to achieve voltage regulation and high efficiency for an extremely wide range of load currents. An experimental 15 W, 3.3 V buck converter has been constructed to demonstrate design and optimization techniques. The converter employs synchronous rectification to reduce conduction

B. Arbetter; R. Erickson; D. Maksimovic

1995-01-01

14

Wire-rope emplacement of diagnostics systems  

SciTech Connect

The study reported here was initiated to determine if, with the Cable Downhole System (CDS) currently under development, there is an advantage to using continuous wire rope to lower the emplacement package to the bottom of the hole. A baseline design using two wire ropes as well as several alternatives are discussed in this report. It was concluded that the advantages of the wire-rope emplacement system do not justify the cost of converting to such a system, especially for LLNL's maximum emplacement package weights.

Burden, W.L.

1982-05-07

15

In-Situ Wire Damage Detection System  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

16

Printed wiring board system programmer's manual  

NASA Technical Reports Server (NTRS)

The printed wiring board system provides automated techniques for the design of printed circuit boards and hybrid circuit boards. The system consists of four programs: (1) the preprocessor program combines user supplied data and pre-defined library data to produce the detailed circuit description data; (2) the placement program assigns circuit components to specific areas of the board in a manner that optimizes the total interconnection length of the circuit; (3) the organizer program assigns pin interconnections to specific board levels and determines the optimal order in which the router program should attempt to layout the paths connecting the pins; and (4) the router program determines the wire paths which are to be used to connect each input pin pair on the circuit board. This document is intended to serve as a programmer's reference manual for the printed wiring board system. A detailed description of the internal logic and flow of the printed wiring board programs is included.

Brinkerhoff, C. D.

1973-01-01

17

Three-level inverter based active power filter for the three-phase, four-wire system  

Microsoft Academic Search

In this paper, the three-phase four-wire active power filter based on a three-level neutral-point-clamped inverter is presented. The proposed active power filter and controller eliminate harmonics in all three phases as well as the neutral current. The existing neutral-point-clamped inverter for a three-phase three-wire system is used for the three-phase four-wire system since the split DC capacitors provide a neutral

Oleg Vodyakho; Taehyung Kim; Sangshin Kwak

2008-01-01

18

A review of wiring system safety in space power systems  

NASA Technical Reports Server (NTRS)

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.

Stavnes, Mark W.; Hammoud, Ahmad N.

1993-01-01

19

DC\\/DC Converters Design and Control for Hybrid Power System  

Microsoft Academic Search

This paper presents ultracapacitor and battery pack modeling with a DC\\/DC converter in a hybrid power system. Ultracapacitor is dimensioned for peak power requirement and battery pack provides the power in steady state. A Topology structure was analyzed that the ultracapacitor system is connected with battery pack parallel after a bidirectional DC\\/DC converter. A detailed theoretical analysis on the control

He Hongwen; Xiong Rui

2010-01-01

20

A new general algorithm of current reference generation for 3-phase 3-wire systems  

Microsoft Academic Search

In this paper, a new general method based on the power balance principle is proposed in order to generate the reference active source currents for an unbalanced 3-phase 3-wire system. This method is based on the zero sequence component expression of a three unbalanced per-phase powers set. The instantaneous total power can be computed from AC or DC side. A

N. B. H. Youssef; K. Al-Haddad

2004-01-01

21

Development of an Ultrahigh Speed Robot FALCON Using Wire Drive System  

Microsoft Academic Search

High speed robots are an important component of modern assembly operations. In this paper, we describe the development of an ultrahigh speed robot named FALCON (Fast Load Conveyance), based on a wire driven parallel manipulation system. It achieves peak accelerations of up to 43G and maximum velocities of 13 m\\/s, even if considerably small DC motors (60W) are used. Due

Sadao Kawamura; W. Choe; S. Tanaka; Shunmugham R. Pandian

1995-01-01

22

Modeling and experimentation of a positioning system of SMA wires  

NASA Astrophysics Data System (ADS)

This work reports two modeling and control attempts performed on a positioning system comprising of linking SMA wires and an overlooking video system for on-line measurements. The first attempt takes the model by Ikuta and identifies experimentally the parameters of the SMA wire. The identified single wire model is then extended to a system of two SMA wires joining together at their tips, based upon which open loop position control of the linkage is then conducted. The approach, however, becomes too complicated when more SMA wires are involved. The second attempt utilizes a neuro-fuzzy based approach for positioning control of a linkage point joining together four SMA wires. The second approach involves four ANFIS neuro-networks with hybrid learning algorithm trained to model the currents to the SMA wires as functions of present and target positions of the linkage point. Experimentation for both the two-wires and four-wires system yield quite satisfactory performance.

Lei, KinFong; Yam, Yeung

2000-06-01

23

Expandable multiterminal DC systems based on voltage droop  

SciTech Connect

This paper introduces a decentralized control scheme for the parallel connection of multiple rectifiers feeding a dc network with numerous inverters. The coordination of multiple HV dc systems without explicit communication is accomplished by the use of dc-side voltages as a droop mechanism. The dc side voltage serves the role of frequency in an ordinary ac system. The approach is most suitable to superconducting dc systems and to dc systems that span small distances and where voltage is relatively uniform throughout the dc system. This paper presents the concept in the context of a high capacity superconducting 10 KV urban infeed.

Johnson, B.K. (Univ. of Idaho, Moscow, ID (United States)); Lasseter, R.H.; Alvarado, F.L. (Univ. of Wisconsin, Madison, WI (United States)); Adapa, R. (Electric Power Research Inst., Palo Alto, CA (United States))

1993-10-01

24

AC\\/DC Smart Control and Power Sharing of DC Distribution Systems  

Microsoft Academic Search

The purpose of this research is to develop a grid connected DC distribution system to ensure efficient integration of different alternate sources to the power system. An investigation of different AC and DC converter topologies and their control is conducted. A new converter topology for sharing DC power was developed to enhance the efficiency and stability of the alternate sources

Mohamed A Elshaer

2012-01-01

25

Life prediction of aging aircraft wiring systems  

NASA Technical Reports Server (NTRS)

The program goal is to develop a computerized life prediction model capable of identifying present aging progress and predicting end of life for aircraft wiring. A summary is given in viewgraph format of progress made on phase 1 objectives, which were to identify critical aircraft wiring problems; relate most common failures identified to the wire mechanism causing the failure; assess wiring requirments, materials, and stress environment for fighter aircraft; and demonstrate the feasibility of a time-temperature-environment model.

Slenski, George

1995-01-01

26

An accurate dc motor speed control system  

Microsoft Academic Search

A dc motor speed control system that uses an oscillator as a frequency reference is described. It provides control with an accuracy determined solely by that of the oscillator. The motor drives a disk with 72 holes which are counted down in a 12 stage binary up\\/down counter. The cycles of the reference oscillator signal are counted up in the

L. Stellema

1974-01-01

27

High-frequency ultrasonic wire bonding systems  

PubMed

The vibration characteristics of longitudinal-complex transverse vibration systems with multiple resonance frequencies of 350-980 kHz for ultrasonic wire bonding of IC, LSI or electronic devices were studied. The complex vibration systems can be applied for direct welding of semiconductor tips (face-down bonding, flip-chip bonding) and packaging of electronic devices. A longitudinal-complex transverse vibration bonding system consists of a complex transverse vibration rod, two driving longitudinal transducers 7.0 mm in diameter and a transverse vibration welding tip. The vibration distributions along ceramic and stainless-steel welding tips were measured at up to 980 kHz. A high-frequency vibration system with a height of 20.7 mm and a weight of less than 15 g was obtained. PMID:10829633

Tsujino; Yoshihara; Sano; Ihara

2000-03-01

28

An Evaluation of Old Armored Cables in Building Wiring Systems  

Microsoft Academic Search

Armored cable has been used in building wiring systems since the early 1900s and remains an accepted wiring method today.\\u000a The original product developed in the early 1900s and that which is commercially available today have significant differences\\u000a in construction and performance. Likewise the demand and expectation of building wiring systems has changed. This paper explores\\u000a some of those differences

John E. Sleights

2011-01-01

29

System and control design of a hybrid active power filter in three-phase four-wire system  

Microsoft Academic Search

In this paper, the system implementation of a hybrid active power filter (HAPF) in three-phase four-wire power system is proposed and discussed. The HAPF is characterized by lower the dc-link rating of the conventional active power filter (APF) without significantly deteriorates the system compensation features and performances. An 110 V \\/ 1.65 KVA HAPF experimental prototype is built in a

Chi-Seng Lam; Man-Chung Wong

2009-01-01

30

Wire 'missing': a rare presentation of preoperative localization wire system dislocation.  

PubMed

A full account is presented of a 53-year-old Chinese woman with a small subpleura nodule in the right upper lobe, which was successfully localized by a Dualok-wire system under computed tomography guidance preoperatively. However, during operation, the hook wire was 'missing', neither in the thorax, nor in the lung. With the help of bed-side chest film, the missing wire, which was twisted in the patient's chest wall, was localized and removed through another small incision. Posterior segmentectomy was administered, and the pulmonary lesion was pathologically diagnosed as atypical alveolar hyperplasia. PMID:25267454

Chen, Xiaofeng; Wang, Shaohua; Hao, Zhenhua; Ma, Qinyun

2014-01-01

31

Evaluation of the intermittent GTA cold wire feed weld system  

SciTech Connect

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.

Dereskiewicz, J.P.

1991-08-01

32

30 CFR 77.704-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2012 CFR

...false Use of grounded messenger wires; ungrounded systems. 77...704-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2012-07-01

33

30 CFR 75.705-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2010 CFR

...false Use of grounded messenger wires; ungrounded systems. 75...705-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2010-07-01

34

30 CFR 75.705-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2012 CFR

...false Use of grounded messenger wires; ungrounded systems. 75...705-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2012-07-01

35

30 CFR 77.704-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2010 CFR

...false Use of grounded messenger wires; ungrounded systems. 77...704-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2010-07-01

36

30 CFR 75.705-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2013 CFR

...false Use of grounded messenger wires; ungrounded systems. 75...705-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2013-07-01

37

30 CFR 77.704-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2011 CFR

...false Use of grounded messenger wires; ungrounded systems. 77...704-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2011-07-01

38

30 CFR 77.704-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2013 CFR

...false Use of grounded messenger wires; ungrounded systems. 77...704-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2013-07-01

39

30 CFR 75.705-11 - Use of grounded messenger wires; ungrounded systems.  

Code of Federal Regulations, 2011 CFR

...false Use of grounded messenger wires; ungrounded systems. 75...705-11 Use of grounded messenger wires; ungrounded systems. Solely...power systems, grounded messenger wires used to suspend the cables of such systems may be used...

2011-07-01

40

System and method for evaluating a wire conductor  

SciTech Connect

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.

Panozzo, Edward; Parish, Harold

2013-10-22

41

A simple three-channel dc SQUID system using time domain multiplexing M. Mck and M. Korn  

E-print Network

A simple three-channel dc SQUID system using time domain multiplexing M. Mück and M. Korn Justus) Conventional multichannel superconducting quantum interference device (SQUID) systems require a SQUID read-out circuit for each channel, as well as many wires connecting each individual SQUID and feedback coil

Le Roy, Robert J.

42

New Solar Cell Power Supply System Using a Boost Type Bidirectinal DC-DC Converter  

Microsoft Academic Search

A 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 sufficiently precise tracking operation performance and satisfactorily high power

Hirofumi Matsuo; Fujio Kurokawa

1984-01-01

43

The performance of 16000 wire mini-drift MWPC system  

Microsoft Academic Search

A Mini-Drift chamber system and associated electronics employed are described. The performance of the system which utilizes 3mm spacing multi-wire proportional chambers produces a spatial resolution of sigma = 180 microns under experimental conditions.

P. Chauvat; R. Cousins; K. Hayes; A. M. Smith; R. Bonino; J. Ellett; M. Medinnis; A. Russ; P. E. Schlein; B. Alitti

1983-01-01

44

A study of cooling magnet-wire of the brushless DC motor for car air conditioner  

Microsoft Academic Search

The electric compressor for car air-conditioners is very high ambient temperature compared with the compressor for household appliances. For this reason, the motor built in this compressor has severe temperature conditions. A cooling design is important in order to improve motor operating temperature on In this research, this temperature is measured paying attention to a magnet wire. Moreover, the cooling

Tomokazu Naruta; Yuji Akiyama; Yuta Niwa

2008-01-01

45

Novel solar cell power supply system using the multiple-input DC-DC converter  

Microsoft Academic Search

Recently, clean electric power generation systems have attracted a great deal of social attention to exploit clean energy resources such as solar arrays, wind generators, fuel cells, etc. In this case, the multiple-input DC-DC power converter is useful to combine the several input power sources and to supply the regulated output voltage for the load. The novel solar cell power

Hirohmi Matsuo; Kimiyoshi Kobayashi; Yutaka Sekine; Matsuyoshi Asano; Lin Wenzhong

1998-01-01

46

Control of DC\\/DC converters for solar energy system with maximum power tracking  

Microsoft Academic Search

Solar power converters were used to convert the electrical energy from solar arrays to a stable and reliable power source. The object of this paper is to analyze and design DC\\/DC power converters of different types in a PV power system to investigate the performance of such converters. A simple method which combines discrete time control and a PI compensator

Chihchiang Hua; Chihming Shen

1997-01-01

47

14 CFR 121.1111 - Electrical wiring interconnection systems (EWIS) maintenance program.  

... 2014-01-01 false Electrical wiring interconnection systems...Continued Airworthiness and Safety Improvements § 121.1111 Electrical wiring interconnection systems...inspections and procedures for electrical wiring interconnection...

2014-01-01

48

14 CFR 121.1111 - Electrical wiring interconnection systems (EWIS) maintenance program.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Electrical wiring interconnection systems...Continued Airworthiness and Safety Improvements § 121.1111 Electrical wiring interconnection systems...inspections and procedures for electrical wiring interconnection...

2013-01-01

49

Aircraft wire system laboratory development : phase I progress report.  

SciTech Connect

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.

Dinallo, Michael Anthony; Lopez, Christopher D.

2003-08-01

50

DC Self Bias Trends in Dual Frequency PECVD Deposition Systems  

NASA Astrophysics Data System (ADS)

Capacitively coupled plasma (CCP) etch systems commonly report the DC auto or self bias developed as a consequence of capacitively coupling RF to the plasma. Frequently, these systems employ wafer pedestals comprised of electrostatic chucks which must monitor the self bias as part of their normal operation. DC self bias is often found to correlate with various etch process behaviors or system states. It is less common, however, to find CCP deposition systems that report DC self bias. This work reports results of a study of DC self bias trends due to chamber pressure, chamber conditioning and aging, and changes in wafer pedestal hardware. In particular, chamber film accumulation is found to correlate to certain DC bias trends. The applicability of these results for process tracking and system monitoring is discussed. Additionally, the DC self bias response to deliberate perturbations to the RF system are examined. These perturbations include those not normally encountered during commercial deposition such as `bleeding' current to ground.

Keil, D. L.; Augustyniak, E.; Leeser, C.; Galli, F.

2011-11-01

51

Decomposition of Currents in Three and Four-Wire Systems  

Microsoft Academic Search

Various methods of instantaneous decomposing of three-phase currents in three- and four-wire systems for the purpose of instantaneous compensation without energy storage are reviewed, analyzed, and compared. It is found that the method of Akagi et al. and other equivalent methods are optimum in the three- and four-wire systems where the neutral current is constrained to be zero after compensation,

Michel Malengret; C. Trevor Gaunt

2008-01-01

52

Multi-Level DC/DC Power Conversion System with Multiple DC Sources  

E-print Network

to interface the battery and the dc bus, one can use separate batteries to power separate converter modules, instead of connecting all batteries in series as one power source and a bi-directional boost converter Xplore. Restrictions apply. #12;a b c Fig. 2. Converter switching states. 42 V Battery L Fig. 3

Tolbert, Leon M.

53

BAE Systems Radiation Hardened SpaceWire ASIC and Roadmap  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

54

American Institute of Aeronautics and Astronautics Active System Identification of a DC-DC Converter Using  

E-print Network

American Institute of Aeronautics and Astronautics 1 Active System Identification of a DC and interactions among modules may cause system instabilities. System identification is generally divided about the system model, and the identification is used to directly compute the system frequency

55

Short-circuit current calculations for dc systems  

SciTech Connect

The aim of the present paper is to describe the methods contained in the International Electrotechnical Commission (IEC) draft Standard ``Calculation of short-circuit currents in dc auxiliary installations in power plants and substations,`` and to test them using the computer dynamic simulation. The test network is a 220-V dc auxiliary system in a power station fed by a static converter. The limits of application of the proposed Standard are also discussed with particular reference to dc traction systems.

Berizzi, A.; Silvestri, A.; Zaninelli, D. [Politecnico di Milano (Italy). Dipt. di Elettrotecnica] [Politecnico di Milano (Italy). Dipt. di Elettrotecnica; Massucco, S. [Univ. degli Studi di Genova (Italy). Dipt. di Ingegneria Elettrica] [Univ. degli Studi di Genova (Italy). Dipt. di Ingegneria Elettrica

1996-09-01

56

A Laser-Wire System at the ATF Extraction Line  

SciTech Connect

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.

Boogert, S.T.; Blair, G.; Boorman, G.; Bosco, A.; Deacon, L.; Driouichi, C.; Karataev, P.; /Royal Holloway, U. of London; Kamps, T.; /BESSY, Berlin; Delerue, N.; Dixit, S.; Foster, B.; Gannaway, F.; Howell, D.F.; Qureshi, M.; Reichold, A.; Senanayake, R.; /Oxford U.; Aryshev, A.; Hayano, H.; Kubo, K.; Terunuma, N.; Urakawa, J.; /KEK, Tsukuba /Liverpool

2007-02-12

57

Novel Solar-Cell Power Supply System Using a Multiple-Input DC–DC Converter  

Microsoft Academic Search

Recently, the clean electric power generation systems have attracted a great deal of social attention to exploit the clean-energy resources such as solar arrays, wind generators, fuel cells, and so forth. In this case, a multiple-input dc–dc converter is useful to combine the several input power sources and to supply the regulated output voltage for the load from the power

Kimiyoshi Kobayashi; Hirofumi Matsuo; Yutaka Sekine

2006-01-01

58

New High Voltage Gain Dual-boost DC-DC Converter for Photovoltaic Power Systems  

Microsoft Academic Search

This article presents a new circuit topology of a high-voltage step-up boost DC-DC converter for photovoltaic power systems. The converter boosts the low-output voltage of the solar cell to the required voltage for the load. The proposed circuit has various advantages compared to the conventional boost converters, namely a higher boost rate with low duty cycle, lower voltage stress on

Khairy Sayed; Mazen Abdel-Salam; Adel Ahmed; Mahmoud Ahmed

2012-01-01

59

Operational environments for electrical power wiring on NASA space systems  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

60

Wired.  

ERIC Educational Resources Information Center

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)

Conklin, Aaron R.

1998-01-01

61

Development of a 55 kW 3X DC-DC Converter for HEV Systems  

E-print Network

) traction drives. It can interface the battery with the inverter dc bus with three output/input voltage. Keywords- DC-DC power conversion; multilevel converter; pulse width modulation; voltage multipliers is a bidirectional dc-dc converter plus an inverter. The dc-dc converter interfaces the battery and the inverter

Tolbert, Leon M.

62

Semiautomatic cold wire feeder systems increase GTA productivity  

SciTech Connect

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.

Richardson, M. (CK Worldwide, Inc., Auburn, WA (United States))

1995-01-01

63

Development of a Production Ready Automated Wire Delivery System  

NASA Technical Reports Server (NTRS)

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.

1997-01-01

64

Shipyard Welding - Development of Extended Length, Continuous Wire Feed Systems.  

National Technical Information Service (NTIS)

The report describes the results of a project for the development of a semiautomatic welding system with appropriate hardware which permits an operator to weld over 200 feet from the power supply and wire source while still providing the flexibility compa...

W. C. Brayton, W. Troyer

1974-01-01

65

NASA/BAE SYSTEMS SpaceWire Effort  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

66

Letter to the Editor: A Comparative Study of Two Power Sources in DC Systems  

Microsoft Academic Search

In this research, the output voltage characteristics of two DC power sources are compared. Both nickel-cadmium DC-DC buck converter and direct ethanol fuel cell DC-DC buck converter systems are experimentally evaluated over a selected switching frequency range. The output voltage characteristics of two types of direct ethanol fuel cell DC-DC buck converter systems are determined. Experimental results are compared to

F. Misoc; J. Lookadoo; M. M. Morcos

2009-01-01

67

14 CFR 129.111 - Electrical wiring interconnection systems (EWIS) maintenance program.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Electrical wiring interconnection systems (EWIS) maintenance...COMMON CARRIAGE Continued Airworthiness and Safety Improvements § 129.111 Electrical wiring interconnection systems (EWIS)...

2011-01-01

68

14 CFR 129.111 - Electrical wiring interconnection systems (EWIS) maintenance program.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Electrical wiring interconnection systems (EWIS) maintenance...COMMON CARRIAGE Continued Airworthiness and Safety Improvements § 129.111 Electrical wiring interconnection systems (EWIS)...

2013-01-01

69

14 CFR 129.111 - Electrical wiring interconnection systems (EWIS) maintenance program.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Electrical wiring interconnection systems (EWIS) maintenance...COMMON CARRIAGE Continued Airworthiness and Safety Improvements § 129.111 Electrical wiring interconnection systems (EWIS)...

2012-01-01

70

14 CFR 129.111 - Electrical wiring interconnection systems (EWIS) maintenance program.  

... 2014-01-01 2014-01-01 false Electrical wiring interconnection systems (EWIS) maintenance...COMMON CARRIAGE Continued Airworthiness and Safety Improvements § 129.111 Electrical wiring interconnection systems (EWIS)...

2014-01-01

71

Electric network solutions of DC transit systems with inverting substations  

Microsoft Academic Search

A detailed model of the R-L-fed inverting substation, for use of power flow and harmonic studies in DC electrified transit systems, has been presented in this paper. A unified Newton-Raphson method is adopted as the solution approach of the AC\\/DC power flows. The harmonic study is performed by the Y-bus method using the derived harmonic current injections of the converter.

Yii-Shen Tzeng; Ruay-Nan Wu; Nanming Chen

1998-01-01

72

Dc power supplies and hard-tube power conditioning systems  

SciTech Connect

In this lecture, we shall discuss some of the major characteristics of dc power supplies and hard-tube pulsers, along with many of their PCS limiting properties and several of the more powerful vacuum tubes that are currently available for larger hard-tube pulsers systems. The initial topic will be elementary dc power supplies, operating with standard 60 Hz AC input power. The full-wave bridge design will be discussed in detail, illustrating the majority of the significant circuit parameters.

Sarjeant, W.J.

1980-01-01

73

AC versus DC distribution systems- Did we get it right?  

SciTech Connect

We presently enjoy a predominantly ac electrical distribution system, the engineering basis for which was designed over 100 years ago. While ac distribution systems have served us well, we should periodically pause to assess what opportunities we have accepted or been denied by the overwhelming predominance of ac electrical power distribution systems. What opportunities could be obtained by engineering dc distribution into at least portions of our present system? What advantages of the present ac distribution system should be recognized and protected? This paper will focus on distribution within premise and low-voltage distribution systems. Specifically, we will address the conversion efficiency costs of adopting various premise ac and dc distribution system topologies. According to a simple predictive model formulated in this paper, premise residential dc distribution will incur unfavorable total conversion efficiency compared with existing ac premise distribution. However, if a residence is supplied by a fuel cell or another dc generator, the total conversion efficiency within a residential dc distribution system could be similar to, or even better than, that for ac distribution.

Hammerstrom, Donald J.

2007-06-28

74

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

NASA Technical Reports Server (NTRS)

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.

2012-01-01

75

Cost effective system for connecting multiwire cables to printed wiring boards  

Microsoft Academic Search

A system flexible enough to meet present and future work requirements was developed. The Component Locator System usually is referred to as a Work Director. The Work Director shows the exact location for installing the wire on the pointed wiring board (PWB) and codes the Cable Scanner for the correct wire. The Cable Scanner then provides an audible signal when

F. H. Lewis

1980-01-01

76

Flat-top system of the DC-280 cyclotron  

NASA Astrophysics Data System (ADS)

The flat-top cavity of the radio-frequency accelerating system designed at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, for the DC-280 cyclotron is described. The cyclotron is intended for increasing the capabilities and efficiency of experiments on the synthesis of super-heavy elements and an investigation of their nuclear physical and chemical properties. The DC-280 isochronous heavy-ion cyclotron will produce accelerated beam of ions in the range from neon to uranium. The parameters, design, and results of the experimental and 3D computer modeling of the flat-top cavity of the RF accelerating system of the DC-280 cyclotron are reported.

Gulbekyan, G. G.; Buzmakov, V. A.; Zarubin, V. B.; Ivanenko, I. A.; Kazarinov, N. Yu.; Karamysheva, G. A.; Franko, I.

2013-07-01

77

Steady State Stability Analysis of AC-DC Power Systems  

Microsoft Academic Search

This thesis presents a comprehensive approach for the steady state stability analysis of AC-DC power systems. A new method is presented for the evaluation of the system state matrix which is then used to determine system stability and develop new algorithms for the stability analysis and control of large power systems.\\u000aThe method exploits the powerful features of the Component

Farooq Ahmad Qureshy

1985-01-01

78

Selection and stability issues associated with a navy shipboard DC zonal electric distribution system  

Microsoft Academic Search

The US Navy is currently investigating the implementation of a DC zonal electric distribution system (DC ZEDS) for the next generation of surface combatant. In replacing the current AC radial distribution system, significant gains can be realized in terms of survivability, weight, manning and cost. DC ZEDS is predicated on having starboard and port DC buses feeding electrical zones delineated

John G. Ciezki; Robert W. Ashton

2000-01-01

79

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

NASA Technical Reports Server (NTRS)

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.

Chowdhury, Badrul H.

2005-01-01

80

Energy Management for Regenerative Brakes on a DC Feeding System  

Microsoft Academic Search

Recently, regenerative brakes are implemented in trains at DC fed electric railways in Japan. Regenerative braking system converts kinetic energy to electrical energy. And other powering trains at the identical feeding circuit must consume the electrical energy. Therefore, when the electrical loads are not sufficient at feeding circuit, braking trains must squeeze regenerative power. The problem is that such braking

Yuruki Okada; Takafumi Koseki; Satoru Sone

81

Design and control of bi-directional DC\\/DC converter for 30kW fuel cell power system  

Microsoft Academic Search

Fuel cell (FC) power system is considered as an alternative energy power generation system in the future. This paper studies the bidirectional DC\\/DC converter for a 30kW three-phase fuel cell power system. The FC power system is sensitive to load characteristics in stand-alone mode, because rapid change or unbalance of the three-phase load will endanger the safety and expectancy of

Xiao Li; Wenping Zhang; Haijin Li; Ren Xie; Dehong Xu

2011-01-01

82

Novel calibration system with sparse wires for CMB polarization receivers  

SciTech Connect

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.

Tajima, O.; /KEK, Tsukuba /Chicago U., KICP; Nguyen, H.; /Fermilab; Bischoff, C.; /Chicago U., KICP /Harvard-Smithsonian Ctr. Astrophys.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

2011-07-01

83

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

SciTech Connect

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.

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

2012-04-15

84

Design and development of a DC-DC converter for a fuel cell inverter system  

E-print Network

(FEC)' organized by the Department of Energy and IEEE in August 2001. An efficient 3-terminal DC-DC push-pull topology was adopted to meet the performance and stringent cost constraints. A broad overview of the DC-AC inverter and its control is also...

Gopinath, Rajesh

2012-06-07

85

Improved dynamic security assessment for AC\\/DC power systems using energy functions  

Microsoft Academic Search

A method is presented to integrate the dynamics of DC power flow into calculations of transient energy functions of AC\\/DC power systems. This method treats the generator input power as a function of the parameters and the input, output variables of the DC damping power controller. By using this transient energy function, the accuracy of the stability prediction of AC\\/DC

Nilkamal Fernandopulle; Robert T. H. Alden

2003-01-01

86

Active disturbance rejection control in steering by wire haptic systems.  

PubMed

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

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

2014-07-01

87

A Multiphase, Modular, Bidirectional, Triple-Voltage DC-DC Converter Power Systems  

SciTech Connect

Electrical power systems in future hybrid and fuel cell vehicles may employ three voltage [14 V, 42 V, and high voltage (HV)] nets. These will be necessary to accommodate existing 14-V loads as well as efficiently handle new heavy loads at the 42-V net and a traction drive on the HV bus. A low-cost DC-DC converter was proposed for connecting the three voltage nets. It minimizes the number of switches and their associated gate driver components by using two half-bridges and a high-frequency transformer. Another salient feature is that the half bridge on the 42-V bus is also utilized to provide the 14-V bus by operating at duty ratios around an atypical value of 1/3. Moreover, it makes use of the parasitic capacitance of the switches and the transformer leakage inductance for soft switching. The use of half bridges makes the topology well suited for interleaved multiphase modular configurations as a means to increase the power level because the capacitor legs can be shared. This paper presents simulation and experimental results on an interleaved two-phase arrangement rated at 4.5 kW. Also discussed are the benefits of operating with an atypical duty ratio on the transformer and a preferred multiphase configuration to minimize capacitor ripple currents.

Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

2008-01-01

88

Phase Lock-In Reflectometry for Detection and Characterization of Wiring System Faults  

NASA Astrophysics Data System (ADS)

This paper describes the preliminary stage in the development of a Phase Lock-in Reflectometry (PLR) technique for detecting, locating and characterizing faults in electrical wiring systems. Results from the more-traditional techniques, e.g. Time-Domain Reflectometry (TDR) and Frequency-Domain Reflectometry (FDR) for detection and location of wiring-system faults are presented and compared with results from the PLR technique. The potential of PLR for characterizing wiring-system faults is briefly discussed. A methodology for combining wiring system models with experimental results to improve the characterization of faults as well as to improve the fundamental understanding of failure mechanisms is also presented.

Ambalam, Harikrishna; Reibel, Richard; Sathish, Shamachary; Frock, Brian

2006-03-01

89

Multi-kw dc power distribution system study program  

NASA Technical Reports Server (NTRS)

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.

Berkery, E. A.; Krausz, A.

1974-01-01

90

Trolleybus power system for operation with AC or DC distribution networks  

Microsoft Academic Search

This paper presents the development and experimental analysis of a special input stage converter for a Trolleybus type vehicle allowing its operation in AC (two wires, single-phase) or DC distribution networks. The architecture of proposed input stage converter is composed by five interleaved boost rectifiers operating in discontinuous conduction mode. Furthermore, due to the power lines characteristics, the proposed input

G. A. Melo; F. A. S. Gonc?alves; R. N. Oliveira; J. M. Muno; M. Santos; C. A. Canesin

2010-01-01

91

NASA/Ames Research Center DC-8 data system  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

92

Feasibility analysis of the application and positioning of DC HTS FCL in a DC microgrid through modeling and simulation using Simulink and SimPowerSystem  

NASA Astrophysics Data System (ADS)

DC fault current limitation in DC distribution network is one of the critical issues which need to be taken care of before they can be practically implemented. High temperature superconductors could be efficiently installed to cope with the problem of DC fault currents. In this paper, a generalized DC high temperature superconducting fault current limiter (SFCL) is modeled by integrating Simulink and SimPowerSystem blocks. This model is designed for limiting DC fault currents in low voltage DC distribution networks. A DC microgrid having a low voltage DC distribution network, an integrated photovoltaic plant and domestic customer load is modeled. Transient analysis of the DC microgrid is performed by generating fault and measuring DC fault currents at critical points. The designed DC SFCL is placed at different strategic locations in DC microgrid and fault current limitation performance of DC SFCL in DC microgrid has been analyzed. Moreover, the affects of rapid impedance changing in the distribution network due to the fault followed by DC SFCL activation is investigated. Finally, the best suitable position and affects of DC SFCL in a DC microgrid along with suggestions for implementation have been proposed.

Khan, U. A.; Shin, W. J.; Seong, J. K.; Oh, S. H.; Lee, S. H.; Lee, B. W.

2011-11-01

93

Three-level half-bridge ZVS DC\\/DC converter for electrolyzer integration with renewable energy systems  

Microsoft Academic Search

This paper presents findings of a R&D project tar geted to the development of a galvanically isolated step-down DC\\/DC converter for electrolyzer integration with renewable energy systems. The topology proposed is a three-level neutral point clamped half-bridge with a high-frequency isolation transformer and a current doubler rectifier that fulfils all the targets set by the designers. Despite an increased component

Anna Andrijanovits; Dmitri Vinnikov; Indrek Roasto; Andrei Blinov

2011-01-01

94

Modelling, simulation and construction of a dc/dc boost power converter: a school experimental system  

NASA Astrophysics Data System (ADS)

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 the feasible introduction of this equipment in undergraduate laboratories.

Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernández-Guzmán, V. M.; Saldaña-González, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

2012-05-01

95

DC Bus Regulation with a Flywheel Energy Storage System  

NASA Technical Reports Server (NTRS)

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.

Kenny, Barbara H.; Kascak, Peter E.

2003-01-01

96

DC Bus Regulation With a Flywheel Energy Storage System  

NASA Technical Reports Server (NTRS)

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.

Kenny, Barbara H.; Kascak, Peter E.

2003-01-01

97

77 FR 41247 - Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for Printing...  

Federal Register 2010, 2011, 2012, 2013

...Prevailing Rate Systems; Abolishment of the Washington, DC, Special Wage Schedule for Printing...issuing an interim rule to abolish the Washington, DC, Federal Wage System (FWS) special...Printing and lithographic employees in the Washington, DC, wage area will now be paid...

2012-07-13

98

Solid state power systems for DC and RF accelerators  

SciTech Connect

Modern accelerator applications require high average and peak powers - particularly RF accelerators and DC accelerators. In many of these applications, it is possible to replace tubes in the power systems with solid state power supplies. In this paper we outline work which we have performed in developing solid state pulsed and CW pulsed power systems for RF linacs and for DC accelerators. We have built and successfully tested a 125 kV, 2.5 MW peak, 60 kW average pulsed power system which is well suited to driving ion beam linacs. This system is modular, with 3 modules capable of driving a large Klystron. The system has been extensively tested with both resistive and fault loads. This type of power supply promises to be less than half as expensive as a conventional thyratron modulator, with considerably more flexibility in pulse duration. We have also powered our Nested High Voltage (NHV) accelerators with a solid state power supply using IGBTs. This type of supply is suitable for both NHV machines, and other Dynamitron style accelerators. Pulsed burst mode excitation of this type of power supply allows us to maintain 1 MV in the NHV accelerator with less than three hundred watts of idling power.

Adler, R. J.; Richter-Sand, R. J. [North Star Research Corporation, 4421 McLeod, NE, Ste. A, Albuquerque, New Mexico, 87109 (United States)

1999-06-10

99

X-wing fly-by-wire vehicle management system  

NASA Technical Reports Server (NTRS)

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.

Fischer, Jr., William C. (Inventor)

1990-01-01

100

Efficient Design in a DC to DC Converter Unit  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

101

Study of degradation within DC93-009 and DC93-029 silicone resin systems  

SciTech Connect

Two Dow Corning potting/filling resins (DC93-009 and DC93-029) mixed and used in production at the Mason and Hanger - Silas Mason Co., Inc., Pantex Plant, have shown to self-polymerize without the presence of curing agent. Each component that goes into one lot of these resins was characterized by chemical and physical methods. The active crosslinker was found to have reacted prematurely with moisture and had lost much of its ability to react with prepolymer. A newly purchased lot of crosslinker has been used to make production lots of both DC93-009 and DC93-029 resins. The new production lots are meeting all required specifications, and the new crosslinker is being tested weekly to monitor product integrity. 11 figs., 2 tabs.

Ewanowski, L.C.

1986-02-01

102

A low-voltage CMOS DC-DC converter for a portable battery-operated system  

Microsoft Academic Search

Motivated by emerging battery-operated applications that demand compact, lightweight, and highly efficient DC-DC power converters, a buck circuit is presented in which all active devices are integrated on a single chip using a standard 1.2 ? CMOS process. The circuit delivers 750 mW at 1.5 V from a 6 V battery. To effectively eliminate switching loss at high operating frequencies,

Anthony J. Stratakos; Seth R. Sanders; Robert W. Brodersen

1994-01-01

103

Novel High Step-Up DC–DC Converter for Fuel Cell Energy Conversion System  

Microsoft Academic Search

A novel high step-up dc-dc converter for fuel cell energy conversion is presented in this paper. The proposed converter utilizes a multiwinding coupled inductor and a voltage doubler to achieve high step-up voltage gain. The voltage on the active switch is clamped, and the energy stored in the leakage inductor is recycled. Therefore, the voltage stress on the active switch

Shih-Kuen Changchien; Tsorng-Juu Liang; Jiann-Fuh Chen; Lung-Sheng Yang

2010-01-01

104

Development of a DC propulsion system for an electric vehicle  

NASA Technical Reports Server (NTRS)

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.

Kelledes, W. L.

1984-01-01

105

Development of an automated wire delivery system for robotic welding applications  

NASA Astrophysics Data System (ADS)

Our Phase 1 study showed new techniques and procedures are required for maintaining the delivery of filler wire into the weld pool for robotic variable polarity plasma arc welding (VPPAW) and gas tungsten arc (GTA) welding applications. Toward this end, the development and implementation of an autonomous wire delivery system appears very feasible utilizing existing proven technologies. In our Phase 1 research effort, we investigated the requirements necessary of a wire delivery system to assure a quality weldment. We also evaluated various sensing technologies for their ability to provide information related to delivery of the wire into the weld pool. Finally, we described the types of software necessary for the automatic wire delivery system. Several approaches for automating the wire delivery system have been suggested, and we recommend the building of a prototype system in our Phase 2 effort as a logical step in the application of this technology to robotic GTA and VPPA welding. Such a prototype would contain the necessary hardware components, sensors and control software for evaluating the performance of the system as applied to the berthing port, main engine and external fuel tank. This tool would be used to demonstrate the worth and plausibility of automating the wire delivery system for each of these applications.

Morris, Timothy B.

1992-07-01

106

Development of an automated wire delivery system for robotic welding applications  

NASA Astrophysics Data System (ADS)

Our Phase 1 study showed new techniques and procedures are required for maintaining the delivery of filler wire into the weld pool for robotic VPPA (variable polarity plasma arc) and GTA (gas tungsten arc) welding applications. Toward this end, the development and implementation of an autonomous wire delivery system appears very feasible utilizing existing proven technologies. In our Phase 1 research effort, we investigated the requirements necessary of a wire delivery system to assure a quality weldment. We also evaluated various sensing technologies for their ability to provide information related to delivery of the wire into the weld pool. Finally, we described the types of software necessary for the automatic wire delivery system. Several approaches for automating the wire delivery system have been suggested, and we recommend the building of a prototype system in our Phase 2 effort as a logical step in the application of this technology to robotic GTA and VPPA welding. Such a prototype would contain the necessary hardware components, sensors and control software for evaluating the performance of the system as applied to the berthing port, main engine and external fuel tank. This tool would be used to demonstrate the worth and plausibility of automating the wire delivery system for each of these applications.

Morris, Timothy B.

1992-07-01

107

Superconductivity for Electric Systems Annual Peer Review Washington, DC July 23-25, 2003 OAK RIDGE NATIONAL LABORATORY  

E-print Network

(Marty) 2G wire manufacturing at AMSC 2G wire characteristics Prototype 2000 Amp 2G cable performance-in ORNL-AMSC CRADA: Development of 2G YBCO-RABiTS Wires #12;Superconductivity for Electric Systems Annual Overall CRADA Objectives Assist AMSC's development of a low-cost, robust 2G wire based on RABi

108

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

109

A DB\\/DC platform for real-time operating systems based on CTRON specifications  

Microsoft Academic Search

A database and data communication (DB\\/DC) platform was developed for real-time operating systems based on CTRON specifications in order to create high performance online transaction processing systems such as network operation control systems. The DB\\/DC platform is designed to be portable and to achieve high performance. The authors describe the software architecture of the DB\\/DC platform for real-time operating systems

Takuo Nishihara; Junichi Kikuchi; Tomoji Takehisa

1992-01-01

110

Application of Superconducting Power Cables to DC Electric Railway Systems  

NASA Astrophysics Data System (ADS)

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.

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

111

Practical Issues Concerned with Zero sequence component and Harmonic Compensation in Four-Wire systems  

Microsoft Academic Search

A minimization problem for the instantaneous active and reactive currents give the optimal solution for the three-wire three-phase systems. This basic solution is simple to implement, but posing practical issues when it is applied to a four-wire three-phase system. The generalized theory of instantaneous powers has been proposed as an alternative to the optimal solution for a general three-phase system.

E. Pashajavid; K. Kanzi; M. T. Bina

2007-01-01

112

THIRD GENERATION COORDINATE READOUT SYSTEM -CROS-3 N.F. Bondar, V.L. Golovtsov, A.G. Golyash, E.A. Lobachev, L.N. Uvarov, S.L. Uvarov, V.I. Yatsura  

E-print Network

fine pitch MultiWire Proportional Chambers (MWPC) and wire Drift Chambers (DC) with hexagonal cell system in Fig. 1 includes: - 96-channel MWPC Digitizers (CDR96); - 16-channel DC Digitizers (AD16); - 16 DC DIGITIZER 15 DC DIGITIZER 16 SYSTEM BUFFER FAST TRIGGER LOGIC MWPC DIGITIZER 1 CONCENTRATOR

Titov, Anatoly

113

Prospective, randomized, single blinded pilot study of a new FlatWire based sternal closure system  

PubMed Central

Background Unstable steel wire cerclage following open heart surgery may result in increased pain, sternal cut-through, non-union, or dehiscence. These complications lead to longer hospital stays, increased cost, higher morbidity, and patient dissatisfaction. The Figure 8 FlatWire Sternal Closure System is a new construct which is a simple, intuitive, and inexpensive alternative for primary sternal repair following open heart surgery. Prior bench-top testing of FlatWire has demonstrated superior strength and stiffness compared to traditional steel wire. We present our initial experience in a prospective, randomized, single blinded pilot study utilizing this FDA approved system. Methods Sixty-three patients undergoing elective complete sternotomies at a single institution were randomly assigned to receive either the Figure 8 FlatWire or standard steel wire cerclage. All surgeries were performed by a single board certified cardiothoracic surgeon. Data collected included: Age, BMI, pump time, off pump to surgical stop time, length of hospital stay after surgery, cost from time of surgery to discharge, and pain on a visual analog pain scale on the day of discharge, day 30, and day 60. Results The groups were well matched. Patients receiving the Figure 8 FlatWire (33) had a reduction in length of stay compared to patients receiving steel wire circlage (30), but it was not statistically significant (6.8 vs. 7.8 days respectively, p?Wire reported significantly decreased pain at day of discharge (3.07 vs. 4.92 points on pain scale, p?Wire vs. steel wires (55.7 vs. 71.6 minutes, p?=?0.00025). Mean cost from surgery until discharge was $87,820.98 in the FlatWire group vs. $91,930.29 in the steel wire group (p?Wire provides excellent stability, which resulted in significantly diminished postoperative pain at discharge. Although not significant there was a trend toward decreased length of stay, and reduced cost. Further clinical research is warranted to expand upon these initial trends and validate long term outcomes. PMID:24889138

2014-01-01

114

30 CFR 75.902-2 - Approved ground check systems not employing pilot check wires.  

...DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground Low- and Medium-Voltage Alternating Current Circuits § 75.902-2 Approved ground check systems not employing pilot check wires....

2014-07-01

115

The instantaneous power theory based on mapping matrices in three-phase four-wire systems  

Microsoft Academic Search

Characteristics of the instantaneous active\\/reactive powers and zero-sequence current\\/voltages are analyzed in three-phase four-wire systems. Control strategy for an active filter without energy storage components is proposed on the basis of mapping matrices. It can compensate for the zero-sequence current, irrespectively of whether or not a zero-sequence voltage exists in three-phase four-wire systems

Hyosung KIM; Hirofumi AKAGI

1997-01-01

116

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

117

Applying OMG D&C Specification and ECA Rules for Autonomous Distributed Component-based Systems  

E-print Network

Applying OMG D&C Specification and ECA Rules for Autonomous Distributed Component-based Systems J, because they are decoupled from the running system which is subject to dynamic changes. The autonomic- ample. Keywords Autonomic computing, Metamodeling, Distributed systems, OMG D&C, ECA rules, Dacar 1

Paris-Sud XI, Université de

118

Power system monitoring and source control of the Space Station Freedom DC power system testbed  

Microsoft Academic Search

Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the DC Power Management

Greg L. Kimnach; Anastacio N. Baez

1992-01-01

119

Power system monitoring and source control of the Space Station Freedom dc-power system testbed  

Microsoft Academic Search

Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the dc Power Management

Greg L. Kimnach; Anastacio N. Baez

1992-01-01

120

A remote wire\\/wireless video monitor system using HW\\/SW co-scheduling RTOS  

Microsoft Academic Search

The remote wire\\/wireless video monitor system (RWVMS) is a video monitor and control system developed successfully by NEUINFO. RWVMS consists of several sub-systems each of them forming a complex independent component. RWVMS covers the task controlling, configuring and monitoring of the system. Since the experiment will be running in a radiation environment, fault tolerance, error correction and system stability in

Hai Xu; Yu Han; Shuisheng Wei; Qingxu Deng; Jin Cui; Shuang Wang; Ge Yu

2005-01-01

121

Power conversion system modification to permit use of DC power source  

NASA Astrophysics Data System (ADS)

The patent application discloses an electrical power conversion system designed to operate on 115 volt, three-phase AC voltage generated by a motor generator. A modification is provided to also permit the use of a DC power source. The power conversion system has a plurality of AC-to-DC conversion means for converting the generated three-phase AC voltages. The first specified DC voltage is supplied to a voltage reduction means and the second specified DC voltage is supplied to a control logic circuit of the power source and means, utilizing power from said DC power source, for supplying DC voltages equivalent to the first and second specified DC voltages. The supplying means is isolated from the generated three-phase voltage such that the power conversion system can operate on: (1) three-phase AC voltage generated by the motor generator; (2) DC voltages equivalent to the first and second specified DC voltages from the supplying means; or (3) a combination of the three-phase AC voltage generated by the motor generator and the DC voltages from the supplying means.

Frank, Thomas A.; Michel, Claude D.

1992-08-01

122

Power conversion system modification to permit use of DC power source  

NASA Astrophysics Data System (ADS)

In an electrical power conversion system designed to operate on three-phase AC voltage generated by a motor generator, a modification is provided to permit the use of a DC power source to operate same. The power conversion system has a plurality of AC-to-DC conversion means for converting the generated three-phase AC voltages. The first specified DC voltage is supplied to a voltage reduction means and the second specified DC voltage is supplied to a control logic circuit of the power' source and means, utilizing power from said DC power source, for supplying DC voltages equivalent to the first and second specified DC voltages. The supplying means is isolated from the generated three-phase voltage such that the power conversion system can operate on: three-phase AC voltage generated by the motor generator, DC voltages equivalent to the first and second specified DC voltages from the supplying means, or a combination of the three-phase AC voltage generated by the motor generator and the DC voltages from the supplying means.

Frank, Thomas A.; Michel, Claude D.

1994-06-01

123

Abstract--Many studies comparing AC and DC systems have focused on efficiency, stability, and controllability, but have not  

E-print Network

system has a separate distribution system providing protection to the overall ship power systems when be achieved by moving to a DC system with three lines. Index Terms-DC power systems, power system modeling. These alternative energies are prevailingly DC. However, the power infrastructure is presently based on an AC system

Tolbert, Leon M.

124

Research study on multi-KW-DC distribution system  

NASA Technical Reports Server (NTRS)

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.

Berkery, E. A.; Krausz, A.

1975-01-01

125

On-chip bidirectional wiring for heavily pipelined systems using network coding  

Microsoft Academic Search

In this paper, we describe a low-area, reduced-power on-chip point-to-point bidirectional communication scheme for heavily pipelined systems. When data needs to be transmitted bidirectionally between two on-chip locations, the traditional approach resorts to either using two unidirectional wires, or to using a single wire (with a unidirectional transfer at any given time instant). In contrast, our bidirectional communication scheme allows

Kalyana C. Bollapalli; Rajesh Garg; Kanupriya Gulati; Sunil P. Khatri

2009-01-01

126

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

NASA Astrophysics Data System (ADS)

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.

Haj-Maharsi, Mohamed Yassine

127

A Novel Structure for Three-Phase Four-Wire Distribution System Utilizing Unified Power Quality Conditioner (UPQC)  

Microsoft Academic Search

This paper presents a novel structure for a three-phase four-wire (3P4W) distribution system utilizing unified power quality conditioner (UPQC). The 3P4W system is realized from a three-phase three-wire system where the neutral of series transformer used in series part UPQC is considered as the fourth wire for the 3P4W system. A new control strategy to balance the unbalanced load currents

Vinod Khadkikar; Ambrish Chandra

2009-01-01

128

The DC-SQUID-based Magnetocardiographic Systems for Clinical Use  

NASA Astrophysics Data System (ADS)

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.

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.

129

Welding Characteristics of Ultrasonic Wire Bonding Using High-Frequency Vibration Systems  

NASA Astrophysics Data System (ADS)

Welding characteristics of ultrasonic wire bonding using 60 kHz, 90 kHz and 120 kHz complex vibration as well as 190 kHz linear vibration welding systems are studied. The locus shapes of the complex vibration welding tip are controlled from linear to elliptical or circular. Aluminum wire specimens of 0.1 mm diameter are welded successfully using complex and high-frequency welding equipment. The required vibration amplitudes of these complex vibration systems are about one-half to one-third and required weld time is shorter than those of a conventional system of linear vibration. The required vibration velocity of a high-frequency system is lower than that of a low-frequency system. The deformations of the welded specimens under adequate welding conditions are almost the same, even if the welding tip vibration locus is altered from linear to elliptical or circular, or the vibration frequency used is changed from 60 kHz to 190 kHz in the case where the same wire specimens are used. Using these methods, the weld strength of wire bonding becomes independent of the difference in the directions of the welding tip vibration and wire length.

Tsujino, Jiromaru; Mori, Takahiro; Hasegawa, Koichi

1994-05-01

130

DC Cool  

NSDL National Science Digital Library

When Forbes Magazine ranked Washington DC the coolest city in America back in August, the web exploded with commentary. A typical tweet: âÂÂWhat makes DC AmericaâÂÂs coolest city? The soul crushing architecture that lines our streets or the hordes of zombies that walk them?â News outlets form the Wire to the Los Angeles Times balked. Even the Washington Post questioned the ranking. Still, DC has a lot to offer. And this hip little site, sponsored by the city, wants to tell you all about it. The Scene features links to Eat + Drink, See + Do, and other categories. Click any photo for a short vignette. For instance, a smiling panda links you to an interview with Nicole MacCorkle, the giant panda keeper at SmithsonianâÂÂs National Zoo.

131

Estimation of Faults in DC Electrical Power System Dimitry Gorinevsky, Stephen Boyd, and Scott Poll  

E-print Network

) and observation equation (2) are similar to linear state space model commonly used in estimation, except the modelEstimation of Faults in DC Electrical Power System Dimitry Gorinevsky, Stephen Boyd, and Scott Poll Abstract-- This paper demonstrates a novel optimization- based approach to estimating fault states in a DC

132

Interface phonon-polaritons in quantum well wire systems of polar ternary mixed crystals  

NASA Astrophysics Data System (ADS)

The interface phonon-polaritons in quasi-one-dimensional rectangular quantum well wire systems consisting of polar ternary mixed crystals have been investigated with the modified random-element-isodisplacement model and the Born-Huang approximation, combined the Maxwell’s equations and the boundary condition of electromagnetic field. The numerical results of the frequencies of interface phonon-polaritons as functions of the wave-vector, geometric structures, as well as composition x for the quantum well wire systems GaAs/AlxGa1-xAs and ZnxCd1-xSe/ZnSe are gained and discussed. It is shown that there are six branches of interface phonon-polariton modes in quantum well wire systems. The effects of “one mode” and “two mode” behaviors of the ternary mixed crystals on the interface modes are also shown in the dispersion curves.

Yan, C. L.; Bao, J.

2014-10-01

133

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

PubMed Central

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

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

2014-01-01

134

49 CFR 236.74 - Protection of insulated wire; splice in underground wire.  

Code of Federal Regulations, 2012 CFR

...of insulated wire; splice in underground wire. 236.74 Section 236.74 Transportation...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.74 Protection of insulated wire; splice in underground wire....

2012-10-01

135

49 CFR 236.74 - Protection of insulated wire; splice in underground wire.  

Code of Federal Regulations, 2013 CFR

...of insulated wire; splice in underground wire. 236.74 Section 236.74 Transportation...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.74 Protection of insulated wire; splice in underground wire....

2013-10-01

136

49 CFR 236.74 - Protection of insulated wire; splice in underground wire.  

Code of Federal Regulations, 2011 CFR

...of insulated wire; splice in underground wire. 236.74 Section 236.74 Transportation...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.74 Protection of insulated wire; splice in underground wire....

2011-10-01

137

49 CFR 236.74 - Protection of insulated wire; splice in underground wire.  

Code of Federal Regulations, 2010 CFR

...of insulated wire; splice in underground wire. 236.74 Section 236.74 Transportation...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.74 Protection of insulated wire; splice in underground wire....

2010-10-01

138

A key to expanding older DC systems with new equipment  

Microsoft Academic Search

Expanding existing DC power plants has been a natural part of telecom operators life for a long, long time. In later years the need to expand has become more frequent, at the same time as performing the expansions has become more difficult. The increased need to expand is due to the increased pace of change in the telecom network. Economical

O. Hellgren

2004-01-01

139

A DC-DC Converter-Based PEM Fuel Cell System Emulator  

E-print Network

. In contrast to classical electricity generation system, such as heat engines, the theoretical electrical systems have made great improvements of its low working temperature. Indeed, the fuel cell is an open to be easily emulated and can be used in laboratory as a low-cost system for design and experimental purposes

Boyer, Edmond

140

Safety considerations of aerial systems using insulated and covered wire and cable  

SciTech Connect

Insulated and covered wires and cables have been used in aerial applications for over fifty years. Their various constructions, characteristics, and applications are discussed in Design and Application of Aerial Systems Using Insulated and Covered Wire and Cable. Some have suggested that covered wires and cables should be used in general applications solely for the purpose of providing safety to operating personnel and the general public. This paper discusses factors leading to the conclusion that nonshielded, covered conductor should not be installed solely to assure personal safety. The National Electrical Safety Code (NESC) treats covered conductors as bare conductors for purposes of clearances to personnel spaces; such a requirement is strongly supported by this paper.

Landinger, C.C.; McAuliffe, J.W. [Hendrix Wire and Cable, Milford, NH (United States)] [Hendrix Wire and Cable, Milford, NH (United States); Clapp, A.L.; Dagenhart, J.B. [Clapp Research Associates, Raleigh, NC (United States)] [Clapp Research Associates, Raleigh, NC (United States); Thue, W.A.

1997-04-01

141

SYSTEM LEVEL BENEFITS OF SILICON CARBIDE POWER DEVICES IN DC-DC CONVERTERS  

Microsoft Academic Search

The superior properties of Silicon Carbide (SiC) power devices compared to Silicon (Si) power devices are expected to have a significant impact on the next-generation power electronics systems. Some of these benefits include a large reduction in the size, weight, and cost of the power conditioning and\\/or thermal systems and passive components. In this paper, Si and SiC diode models

Burak Ozpineci; Leon M. Tolbert; S. Kamrul Islam

142

Wide-range ac \\/ dc earth leakage current sensor using fluxgate with self-excitation system  

Microsoft Academic Search

This paper describes an ac \\/ dc earth leakage current sensor using fluxgate magnetic sensor, which provides high sensitivity for wide-range current sensing. The fluxgate current sensor with self-excitation system can be used to detect small ac \\/ dc current of 10mA. Two kinds of detecting which pulse width and pulse frequency could be used in this system to achieve

Takahiro Kudo; Susumu Kuribara; Yasuhiro Takahashi

2011-01-01

143

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

NASA Technical Reports Server (NTRS)

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.

Hankins, J. D.

1974-01-01

144

Power quality improvement in three-phase four-wire systems using shunt active filters  

Microsoft Academic Search

This paper presents a shunt active filter control using the instantaneous power theory on a rotating reference frame for power quality improvement in 3-phase 4-wire system. By current space vector mapping on rotating reference frame, three linearly independent components are derived. The defined powers can be controlled by current vector components. The in-phase current vector component to voltage vector is

A. Esfandiari; M. Parniani; H. Mokhtari

2004-01-01

145

Point of collapse methods applied to AC\\/DC power systems  

Microsoft Academic Search

The authors describe an extension of the point of collapse method developed for studies of AC systems to the determination of saddle-node bifurcations in power systems including high voltage direct current (HVDC) transmission. Bus voltage profiles are illustrated for an AC\\/DC test system. They significantly differ from the profiles of pure AC systems for typical system models. In particular, voltage

C. A. Canizares; Fernando L. Alvarado; Christopher L. DeMarco; Ian Dobson; Willis F. Long

1992-01-01

146

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

SciTech Connect

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.

Levashov, Michael Y.

2010-12-01

147

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

SciTech Connect

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.

Not Available

2010-11-29

148

Electrical endurance of Co/Ni wire for magnetic domain wall motion device  

NASA Astrophysics Data System (ADS)

We investigated electrical endurance of perpendicularly magnetized Co/Ni wires, which are a promising candidate material system for current-induced domain wall motion device. Monitoring the wire resistance while applying dc stress is shown to be a promising way to evaluate the electrical breakdown. An electromigration model describes well the observed time-to-failure as a function of temperature and current density. The dc stress current density which leads to 10-yr lifetime with 50% failure at 150 °C was twice as large as the threshold current density for domain wall motion, suggesting that the device with Co/Ni wire is highly durable against electrical stresses.

Fukami, S.; Yamanouchi, M.; Honjo, H.; Kinoshita, K.; Tokutome, K.; Miura, S.; Ikeda, S.; Kasai, N.; Ohno, H.

2013-06-01

149

Evolution of the Design of a Second Generation FireWire Based Data Acquisition System  

PubMed Central

Our laboratory has previously reported on the basic design concepts of an updated FireWire based data acquisition system for depth-of-interaction detector systems designed at the University of Washington. The new version of our data acquisition system leverages the capabilities of modern field programmable gate arrays (FPGA) and puts almost all functions into the FPGA, including the FireWire elements, the embedded processor, and pulse timing and integration. The design is centered around an acquisition node board (ANB) that includes 64 serial ADC channels, one high speed parallel ADC, FireWire 1394b support, the FPGA, a serial command bus and signal lines to support a rough coincidence window implementation to reject singles events from being sent on the FireWire bus. Adapter boards convert detector signals into differential paired signals to connect to the ANB. In this paper we discuss many of the design details, including steps taken to minimize the number of layers in the printed circuit board and to avoid skewing of parallel signals and unwanted bandwidth limitations. PMID:22228135

Lewellen, T.K.; Miyaoka, R.S.; MacDonald, L.R.; Haselman, M.; DeWitt, D.; Hauck, S.

2011-01-01

150

A control of vehicle using steer-by-wire system with hardware-in-the-loop-simulation system  

Microsoft Academic Search

In this study, a steer-by-wire system is applied to a control vehicle. A SBW system is composed of two motors controlled by an ECU instead of mechanical linkage. Two motors follow general EPS system modeling. One motor in the steering wheel is to improve the driver's steering feed and the other motor in the steering linkage is to improve the

Seok-Hwan Jang; Tong-Jin Park; Chang-Soo Han

2003-01-01

151

Welding Characteristics of Ultrasonic Wire Bonding Using High-Frequency Vibration Systems  

NASA Astrophysics Data System (ADS)

Welding characteristics of ultrasonic wire bonding using 60 kHz and 90 kHz complex vibration as well as 120 kHz linear vibration welding systems are studied. The locus shapes of the complex vibration welding tip are controlled from linear to elliptical or circular. Aluminum wire specimens of 0.1 mm diameter are welded successfully using the welding equipment. The required vibration amplitudes of these complex vibration systems are about one-half to one-third and required weld time is shorter than those for a conventional system of linear vibration. The required vibration velocity of a higher-frequency system is smaller than that of a lower-frequency system.

Tsujino, Jiromaru; Mori, Takahiro; Onozato, Takashi; Hasegawa, Koichi

1993-05-01

152

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

Federal Register 2010, 2011, 2012, 2013

...500-1] Drucker, Inc., DynaMotive Energy Systems Corp., and Gate to Wire Solutions, Inc., Order of Suspension of Trading September...current and accurate information concerning the securities of Gate to Wire Solutions, Inc. because it has not filed any...

2012-09-20

153

A Wire Patch Cell Exposure System for in vitro Experiments at Wi-Fi Frequencies  

Microsoft Academic Search

In order to study possible biological effects of electromagnetic (EM) fields generated by Wi-Fi devices, an exposure system based on a Wire Patch Cell (WPC) has been designed, fabricated and fully characterized. The system is suitable to expose, in the whole band of the Wi-Fi signal, cell monolayers plated on the bottom of four 35-mm Petri dishes, filled with 2

Alessandra Paffi; Micaela Liberti; Vanni Lopresto; Caterina Merla; Rossella Lodato; Giorgio Alfonso Lovisolo; Francesca Apollonio

2010-01-01

154

Through-Space Conjugated Molecular Wire Comprising Three ?-Electron Systems.  

PubMed

A [2.2]paracyclophane-based through-space conjugated oligomer comprising three ?-electron systems was designed and synthesized. The arrangement of three ?-conjugated systems in an appropriate order according to the energy band gap resulted in efficient unidirectional photoexcited energy transfer by the Förster mechanism. The energy transfer efficiency and rate constants were estimated to be >0.999 and >10(12) ?s(-1) , respectively. The key point for the efficient energy transfer is the orientation of the transition dipole moments. The time-dependent density functional theory (TD-DFT) studies revealed the transition dipole moments of each stacked ?-electron system; each dipole moment was located on the long axis of each stacked ?-electron system. This alignment of the dipole moments is favorable for fluorescence resonance energy transfer (FRET). PMID:25056560

Morisaki, Yasuhiro; Kawakami, Naoya; Shibata, Shotaro; Chujo, Yoshiki

2014-10-01

155

Design considerations of a cable wiring system for a new medical center to support a future medical imaging system  

Microsoft Academic Search

Our Medical Center is faced with the problem to design a cable wiring system today, install it by the middle 1990's, and allow for upgrades and enhancements for the next ten to fifteen years. The cable plant must be able to support functions and activities which are poorly defined today, but will include the hospital information system (HIS), a future

Robert M. Witt; Jack Emrich

1992-01-01

156

Instantaneous Reactive Power Theory to N Wire Systems  

Microsoft Academic Search

The control strategy derived from the instantaneous reactive power theory is one of the most commonly used in the Active Power Filters (APFs). For the last decades other formulations have been developed in order to achieve compensation objectives different to the proposed in the original one. Nevertheless, all of them can be only applied to three-phase systems, i.e.: in those

R. S. Herrera; P. Salmeron; J. R. Vazquez; S. P. Litran

2007-01-01

157

Places Wire  

NSDL National Science Digital Library

Are you curious to learn more about cities? You'd do well to make a beeline for the Places Wire site, which offers a cornucopia of material on urban parks, public policy, architecture, planning, and other topics. In sum total, the site is a "curated feed of news and commentary on architecture, landscape and urbanism." The site has partnered with 20 different organizations to provide new content on a daily basis. Some of the recent articles that have found their way to the site include "9 Suggestions for Changing DC's Height Limit" and "The Demise of the Public Hearing." Visitors can also use the drop-down View tab to scroll through the last few hours or days, as the content is quite dynamic. One gem that should not be missed is the archived appearance of Frank Lloyd Wright as a guest on the 1950s television program "What's My Line?"

158

AC Versus DC Distribution SystemsDid We Get it Right?  

Microsoft Academic Search

We presently enjoy a predominantly AC electrical distribution system, the engineering basis for which was designed over 100 years ago. While AC distribution systems have served us well, we should periodically pause to assess what opportunities we have accepted or been denied by the overwhelming predominance of AC electrical power distribution systems. What opportunities could be obtained by engineering DC

Donald J. Hammerstrom

2007-01-01

159

Radio frequency dc-dc power conversion  

E-print Network

THIS THESIS addresses the development of system architectures and circuit topologies for dc-dc power conversion at very high frequencies. The systems architectures that are developed are structured to overcome limitations ...

Rivas, Juan, 1976-

2007-01-01

160

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

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

161

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

NASA Technical Reports Server (NTRS)

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.

2002-01-01

162

International space station wire program  

NASA Technical Reports Server (NTRS)

Hardware provider wire systems and current wire insulation issues for the International Space Station (ISS) program are discussed in this viewgraph presentation. Wire insulation issues include silicone wire contamination, Tefzel cold temperature flexibility, and Russian polyimide wire insulation. ISS is a complex program with hardware developed and managed by many countries and hundreds of contractors. Most of the obvious wire insulation issues are known by contractors and have been precluded by proper selection.

May, Todd

1995-01-01

163

Design and application of aerial systems using insulated and covered wire and cable  

SciTech Connect

Insulated and covered wires and cables have been used in aerial applications for over fifty years. Despite this long history, the design, application and operation of these different types of conductor constructions are frequently misunderstood and confused with one another. Utilities have increasing needs for greater reliability and higher quality of service, growing concerns over electromagnetic fields, increased difficulty in obtaining right-of-way and tree trimming, and difficulty in maintaining clearances in congested areas. These challenges have resulted in expanded interest in using covered or insulated cables in aerial systems. This paper (a) describes the differences between the constructions, (b) answers questions, concerns and misconceptions about these aerial designs, and (c) ranks the performance of each relative to desired attributes. A logical system for classifying covered wire and cable is proposed.

Clapp, A.L.; Dagenhart, J.B. [Clapp Research Associates, Raleigh, NC (United States)] [Clapp Research Associates, Raleigh, NC (United States); Landinger, C.C.; McAuliffe, J.W. [Hendrix Wire and Cable, Milford, NH (United States)] [Hendrix Wire and Cable, Milford, NH (United States); Thue, W.A.

1997-04-01

164

NASA/BAE Systems SpaceWire Efforts  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

165

Analysis of power losses for instantaneous compensation of three-phase four-wire systems  

Microsoft Academic Search

This paper deals with the effect that the instantaneous compensation in three-phase four-wire systems, including or not the compensation of the neutral current, has on the supply line power losses. Thus, for three-phase circuits, the instantaneous compensation criterion has been established based on the instantaneous power theory. According to the instantaneous value concept the noninstantaneous power current is reduced, without

Juan-Carlos Montaño; Patricio Salmerón; Jaime Prieto Thomas

2005-01-01

166

Compensation Algorithms Applied to Power Quality conditioners in three-phase four-wire systems  

Microsoft Academic Search

This work presents compensation algorithm schemes used in power quality conditioners applied to three-phase four-wire systems, allowing harmonic current suppression and reactive power compensation which results in an effective power factor correction. The strategies used to extract the three-phase compensation currents are based on the synchronous reference frame method. Although this method is itself based on balanced three-phase loads, it

Sergio A. Oliveira da Silva; R. A. Modesto; A. Goedtel; C. F. Nascimento

2010-01-01

167

Control strategies for active power filter in three-phase four-wire systems  

Microsoft Academic Search

In this paper, new control strategies for an active power filter (APF) under balanced and unbalanced load conditions in three-phase four-wire power systems are presented. A reference current generator is designed and space vector modulation (SVPWM) is employed to eliminate harmonic currents in each phase and in the neutral line along with compensation to the reactive power. A per-phase harmonic

Sangsun Kim; Prasad N. Enjeti

2000-01-01

168

A new method for instantaneous reactive power compensation in three-phase four-wire systems  

Microsoft Academic Search

This paper proposes a novel method to generate the current reference for a parallel active power filter that does not need energy storage elements. The method compensates for the reactive power and eliminates the neutral current in unbalanced three-phase four-wire systems (sinusoidal or nonsinusoidal) with or without zero-sequence components in the currents and \\/or voltages. In contrast with existing methods,

C. A. Buada; Juan Carlos Balda

2004-01-01

169

Detection of High-Impedance Arcing Faults in Radial Distribution DC Systems  

NASA Technical Reports Server (NTRS)

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

Gonzalez, Marcelo C.; Button, Robert M.

2003-01-01

170

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

NASA Technical Reports Server (NTRS)

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

Gonzalez, Marcelo C.; Button, Robert M.

2003-01-01

171

Cable Bundle Wire Derating  

NASA Technical Reports Server (NTRS)

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.

Lundquist, Ray A.; Leidecker, Henning

1998-01-01

172

Cable Bundle Wire Derating  

NASA Technical Reports Server (NTRS)

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.

Lundquist, Ray A.; Leidecker, Henning

1998-01-01

173

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

ERIC Educational Resources Information Center

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…

Gunasekaran, M.; Potluri, R.

2012-01-01

174

Genetic-Fuzzy Sliding Mode Controller for a DC Servomotor system  

Microsoft Academic Search

A Genetic-Fuzzy Sliding Mode Controller is presented for DC Servomotor system control. The fuzzy logic controller was optimized by Genetic Algorithm method to reduce and eliminate the chattering phenomenon. To demonstrate the effectiveness of the presented approach, a comparison between the proposed system, and standard Sliding Mode controller were conducted. Simulation results have shown the advantages of choosing the proposed

Mohammad A. Jaradat; Mohammad I. Awad; Bashar Sami El-Khasawneh

2012-01-01

175

Composite Cu\\/Fe\\/MgB2 superconducting wires and MgB2\\/YSZ\\/Hastelloy coated conductors for ac and dc applications  

Microsoft Academic Search

We discuss the results of a study of MgB2 multifilamentary conductors and coated conductors from the point of view of their future dc and ac applications. The correlation between the slope of the irreversibility line induced by neutron irradiation defects and in situ structural imperfections and the critical temperature and critical current density is discussed with respect to the conductor

B. A. Glowacki; M. Majoros; M. Vickers; M. Eisterer; S. Toenies; H. W. Weber; M. Fukutomi; K. Komori; K. Togano

2003-01-01

176

SEMICONDUCTOR INTEGRATED CIRCUITS: A variable step-down conversion ratio switched capacitor DC-DC converter for energy harvesting systems working in intermittent mode  

NASA Astrophysics Data System (ADS)

Energy harvesting systems stimulate the development of power management for low power consumption applications. Improving the converter efficiency of power management circuits has become a significant issue in energy harvesting system design. This paper presents a variable step-down conversion ratio switched capacitor (SC) DC-DC converter to advance the converter efficiency of charge on the stored capacitor in a wireless monitoring system of orthopedic implants. The converter is designed to work at 1 MHz switching frequency and achieves 15 to 2 V conversion. Measurement results show that the converter efficiency can reach 42% including all circuit power consumption, which is much higher than previous work.

Wenhan, Hao; Chen, Jia; Hong, Chen; Chun, Zhang; Zhihua, Wang

2009-12-01

177

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

178

Intelligent electrical harness connector assembly using Bell Helicopter Textron's 'Wire Harness Automated Manufacturing System'  

NASA Astrophysics Data System (ADS)

Bell Helicopter Textron, Incorporated (BHTI) installed two Digital Equipment Corporation PDP-11 computers and an American Can Inc. Ink Jet printer in 1980 as the cornerstone of the Wire Harness Automated Manufacturing System (WHAMS). WHAMS is based upon the electrical assembly philosophy of continuous filament harness forming. This installation provided BHTI with a 3 to 1 return-on-investment by reducing wire and cable identification cycle time by 80 percent and harness forming, on dedicated layout tooling, by 40 percent. Yet, this improvement in harness forming created a bottle neck in connector assembly. To remove this bottle neck, BHTI has installed a prototype connector assembly cell that integrates the WHAMS' data base and innovative computer technologies to cut harness connector assembly cycle time. This novel connector assembly cell uses voice recognition, laser identification, and animated computer graphics to help the electrician in the correct assembly of harness connectors.

Springer, D. W.

179

Cost effective system for connecting multiwire cables to printed wiring boards. Final report  

Microsoft Academic Search

The high density wiring used on newer electronic devices requires an improved processing technique to eliminate wiring errors and difficulties in reworking assemblies. For example, one subassembly has three cables and three connectors containing approximately 130 wires that terminate on a printed wiring board (PWB). The board is approximately 50.8 mm wide by 101.6 mm long, contains about 20 components,

1980-01-01

180

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

Code of Federal Regulations, 2012 CFR

... false Tagging of wires and interference of wires or tags with signal apparatus. 236.76 ...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.76 Tagging of wires and interference of wires or tags with...

2012-10-01

181

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

Code of Federal Regulations, 2010 CFR

... false Tagging of wires and interference of wires or tags with signal apparatus. 236.76 ...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.76 Tagging of wires and interference of wires or tags with...

2010-10-01

182

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

Code of Federal Regulations, 2013 CFR

... false Tagging of wires and interference of wires or tags with signal apparatus. 236.76 ...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.76 Tagging of wires and interference of wires or tags with...

2013-10-01

183

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

Code of Federal Regulations, 2011 CFR

... false Tagging of wires and interference of wires or tags with signal apparatus. 236.76 ...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.76 Tagging of wires and interference of wires or tags with...

2011-10-01

184

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

NASA Astrophysics Data System (ADS)

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.

Béthoux, O.; Cathelin, J.

2010-12-01

185

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

186

Quantum-classical correspondence for a dc-biased cavity resonator--Cooper-pair transistor system  

E-print Network

We investigate the quantum versus classical dynamics of a microwave cavity-coupled-Cooper pair transistor (CPT) system, where an applied dc bias causes the system to self-oscillate via the ac Josephson effect. Varying the dc bias allows the self-oscillation frequency to be tuned. An unusual feature of the system design is that the dc bias does not significantly affect the high quality factor of the cavity mode to which the CPT predominantly couples. The CPT-cavity mode system has a mechanical analogue involving a driven coupled pendulum-oscillator system. The corresponding, nonlinear classical dynamical equations exhibit chaotic, as well as aperiodic motions depending on the initial conditions and the nature and strengths of the damping/noise forces. The quantum master equation exhibits such phenomena as dynamical tunneling and the generation of non-classical states from initial classical states. Obviating the need for an external ac-drive line, which typically is harder to noise filter than a dc bias line, the self-oscillating system described here has considerable promise for demonstrating macroscopic quantum dynamical behavior.

Miles Blencowe; Andrew Armour; Alex Rimberg

2011-06-29

187

Power system monitoring and source control of the Space Station Freedom dc-power system testbed  

NASA Technical Reports Server (NTRS)

Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the dc Power Management and Distribution (PMAD) Testbed which NASA LeRC has developed at the Power System Facility (PSF) located in Cleveland, Ohio. The testbed is an ideal platform to develop, integrate, and verify power system monitoring and control algorithms. State Estimation (SE) is a monitoring tool used extensively in terrestrial electric utilities to ensure safe power system operation. It uses redundant system information to calculate the actual state of the EPS, to isolate faulty sensors, to determine source operating points, to verify faults detected by subsidiary controllers, and to identify high impedance faults. Source control and monitoring safeguard the power generation and storage subsystems and ensure that the power system operates within safe limits while satisfying user demands with minimal interruptions. System monitoring functions, in coordination with hardware implemented schemes, provide for a complete fault protection system. The objective of this paper is to overview the development and integration of the state estimator and the source control algorithms.

Kimnach, Greg L.; Baez, Anastacio N.

1992-01-01

188

Power system monitoring and source control of the Space Station Freedom DC power system testbed  

NASA Technical Reports Server (NTRS)

Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the DC Power Management and Distribution (PMAD) Testbed which NASA LeRC has developed at the Power System Facility (PSF) located in Cleveland, Ohio. The testbed is an ideal platform to develop, integrate, and verify power system monitoring and control algorithms. State Estimation (SE) is a monitoring tool used extensively in terrestrial electric utilities to ensure safe power system operation. It uses redundant system information to calculate the actual state of the EPS, to isolate faulty sensors, to determine source operating points, to verify faults detected by subsidiary controllers, and to identify high impedance faults. Source control and monitoring safeguard the power generation and storage subsystems and ensure that the power system operates within safe limits while satisfying user demands with minimal interruptions. System monitoring functions, in coordination with hardware implemented schemes, provide for a complete fault protection system. The objective of this paper is to overview the development and integration of the state estimator and the source control algorithms.

Kimnach, Greg L.; Baez, Anastacio N.

1992-01-01

189

DC/AC Student Guide: Solar Energy Power System  

NSDL National Science Digital Library

The purpose of this lab is to be able to measure and calculate basic values such as voltage, current, power, and efficiencies for a power system. Alternative energy is a hot topic these days and much emphasis is being placed on being "green." A "green" system is one that was intentionally designed with high-energy efficiency in mind and also that it be more environmental friendly that previous systems. As time passes more and more alternative energy systems will be placed "on-line." A technician must have the skills to measure such systems and determine if components are in need of replacement and if the systems are operating within operating specifications. Users must create a free account to download this resource.

2014-08-28

190

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)

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.

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

2014-06-01

191

Wire system aging assessment and condition monitoring using Line Resonance Analysis (LIRA)  

SciTech Connect

This paper describes a method for wire system condition monitoring, developed at the IFE Halden Reactor Project, which is based on Frequency Domain Reflectometry. This method resulted in the development of a system called LIRA (Line Resonance Analysis), which can be used on-line to detect local or global changes in the cable electrical parameters as a consequence of insulation faults or degradation. This paper presents some results achieved in field experiments on signal cables for nuclear installations, in USA and Europe. (authors)

Fantoni, P. F. [IFE Halden Reactor Project, P.O. Box 173, Halden, 1751 (Norway); Toman, G. J. [Electric Power Research Inst., 1300 WT Harris Blvd., Charlotte, NC 28262 (United States)

2006-07-01

192

Complex band structure eigenvalue method adapted to Floquet systems: topological superconducting wires as a case study.  

PubMed

For systems that can be modeled as a single-particle lattice extended along a privileged direction, such as, for example, quantum wires, the so-called eigenvalue method provides full information about the propagating and evanescent modes as a function of energy. This complex band structure method can be applied either to lattices consisting of an infinite succession of interconnected layers described by the same local Hamiltonian or to superlattices: systems in which the spatial periodicity involves more than one layer. Here, for time-dependent systems subject to a periodic driving, we present an adapted version of the superlattice scheme capable of obtaining the Floquet states and the Floquet quasienergy spectrum. Within this scheme the time periodicity is treated as existing along a spatial dimension added to the original system. The solutions at a single energy for the enlarged artificial system provide the solutions of the original Floquet problem. The method is suited for arbitrary periodic excitations, including strong and anharmonic drivings. We illustrate the capabilities of the methods for both time-independent and time-dependent systems by discussing: (a) topological superconductors in multimode quantum wires with spin-orbit interaction and (b) microwave driven quantum dots in contact with a topological superconductor. PMID:24353216

Reynoso, Andres A; Frustaglia, Diego

2014-01-22

193

IEC draft Standard evaluation and dynamic simulation of short-circuit currents in dc systems  

SciTech Connect

In this paper the authors verify the calculation procedures proposed in the IEC draft Standard for the evaluation of short-circuit currents in dc auxiliary systems of power plants and substations. The dynamic simulation performed on test networks by the program EMTP, is taken as a reference for a comparative analysis of the two approaches.

Berizzi, A.; Silvestri, A.; Zaninelli, D. [Politecnico di Milano (Italy). Dipt. di Elettrotecnica; Massucco, S. [Univ. degli Studi di Genova (Italy). Dipt. di Ingegneria Elettrica

1995-12-31

194

Improved DC power flow method based on empirical knowledge of the system  

Microsoft Academic Search

This paper presents a new method to improve the accuracy of the DC power flow results while maintaining its computation efficiency and linear formulation. The proposed method uses empirical knowledge of the system, including observed voltage magnitudes and angles from historical data, to formulate correction terms. The correction terms are applied to bus power injections and line admittance matrix when

Shuai Lu; Ning Zhou; Nirupama Prakash Kumar; Nader Samaan; Bhujanga B. Chakrabarti

2010-01-01

195

Power Management Control in DC-electrified Railways for Regenerative Braking Systems of Electric Trains  

Microsoft Academic Search

The most electric trains in DC-electrified railways are presently equipped with regenerative braking system. On braking, traction controller of a train converts kinetic energy to electrical energy during deceleration of the train when other powering trains consume the electrical energy as electrical loads for the regenerating train in the electrical circuit. Therefore, the traction controller of the braking train must

Yuruki OKADA; Takafumi KOSEKI; Kohei HISATOMI

196

Dynamic CT scanner environment effects on a DC electromagnetic tracking system  

E-print Network

D, Vaibhav Patil MD, Raul San Jose Estepar PhD, Conor James Walsh MS CT Scanner Gantry is RotatingDynamic CT scanner environment effects on a DC electromagnetic tracking system Kirby Vosburgh Ph was moving. Summary We have demonstrated that a CT scanner induces increased variability in EM sensor

197

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

NASA Astrophysics Data System (ADS)

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.

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

198

A low cost, DC-coupled active vibration isolation system  

E-print Network

In this thesis, I designed and implemented an isolation system that interfaces with traditional air mounts for improved force disturbance rejection relative to passive optical tables.Force disturbance rejection and position ...

Miu, Kevin Kar-Leung

2008-01-01

199

Annular suspension and pointing system with controlled DC electromagnets  

NASA Technical Reports Server (NTRS)

The Annular Suspension and Pointing System (ASPS) developed by the Flight System division of Sperry Corporation is a six-degree of freedom payload pointing system designed for use with the space shuttle. This magnetic suspension and pointing system provides precise controlled pointing in six-degrees of freedom, isolation of payload-carrier disturbances, and end mount controlled pointing. Those are great advantages over the traditional mechanical joints for space applications. In this design, we first analyzed the assumed model of the single degree ASPS bearing actuator and obtained the plant dynamics equations. By linearizing the plant dynamics equations, we designed the cascade and feedback compensators such that a stable and satisfied result was obtained. The specified feedback compensator was computer simulated with the nonlinearized plant dynamics equations. The results indicated that an unstable output occurred. In other words, the designed feedback compensator failed. The failure of the design is due to the Taylor's series expansion not converging.

Vu, Josephine Lynn; Tam, Kwok Hung

1993-01-01

200

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

NASA Technical Reports Server (NTRS)

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.

Krauthamer, S.

1988-01-01

201

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

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

202

Hydrogen Storage Systems Analysis Working Group Meeting Argonne DC Offices  

E-print Network

is to leverage expertise, complement related work of different individuals and groups, and facilitate the effects of metal hydride properties on the performance of hydrogen storage systems. Bob Bowman (JPL storage media. Finally, Matt Ringer (NREL) provided an update on the H2A delivery models that now also

203

Three generations of DC power systems for experimental small satellites  

Microsoft Academic Search

The University of Surrey has launched 12 small satellites into orbit since 1981, demonstrating convincingly that low cost, reliable spacecraft can be engineered using standard components and techniques, as opposed to the expensive approach practiced by space agencies. Moreover, initial design to orbital operation takes only 12 to 18 months. The power system is a critical part of the spacecraft

V. M. Van der Zel; M. J. Blewett; C. S. Clark; D. C. Hamill

1996-01-01

204

Basic Wiring.  

ERIC Educational Resources Information Center

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;…

Kaltwasser, Stan; And Others

205

Recovery semantics for a DB\\/DC system  

Microsoft Academic Search

Presented is a unified, systematic view of integrity\\/recovery as it relates to a data-processing system—whether man, machine, or both. The concept, sphere of control (SOC), as a bound around a process, is developed to permit describing and solving many of the rather aggravating problems of auditability, repeatability, reproducibility, scheduling, consistency, recovery and general integrity. Identified are the relationships among resources

Charles T. Davies Jr.

1973-01-01

206

An optimal operating point control of lithium-ion battery in a power compensator for DC railway system  

Microsoft Academic Search

An optimal operating point control method of lithium-ion battery for a power compensator of a DC railway system is developed in this paper. The compensator consists of a DC\\/DC converter and a lithium-ion battery bank. The regenerative energy is stored to the battery, and the energy is released to powering trains. The charging and discharging currents are determined according to

Masayuki Sadakiyo; Naoto Nagaoka; Akihiro Ametani; Shigeki Umeda; Yoshiaki Nakamura; Jun Ishii

2007-01-01

207

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

NASA Technical Reports Server (NTRS)

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.

Appelbaum, Joseph; Singer, S.

1989-01-01

208

A multilevel voltage-source converter system with balanced dc voltages  

SciTech Connect

A multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as large induction motor drives, back-to-back interconnected power systems, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the dc capacitors. The problem may be solved by use of additional voltage regulators or separate dc sources. However, these solutions are found not to be practicable for most applications. The proposed converter system can solve the voltage unbalance problem of the conventional multilevel voltage-source converters, without using any additional voltage balance circuits or separate voltage sources. Mechanism of the voltage unbalance problem is analyzed theoretically in this paper. The validity of the new converter system is demonstrated by simulation and experiment.

Peng, Fang Zheng [Tennessee Univ., Knoxville, TN (United States); Lai, Jih-Sheng; McKeever, J.; VanCoevering, J. [Oak Ridge National Lab., TN (United States)

1995-04-01

209

High-conductive organometallic molecular wires with delocalized electron systems strongly coupled to metal electrodes.  

PubMed

Besides active, functional molecular building blocks such as diodes or switches, passive components, for example, molecular wires, are required to realize molecular-scale electronics. Incorporating metal centers in the molecular backbone enables the molecular energy levels to be tuned in respect to the Fermi energy of the electrodes. Furthermore, by using more than one metal center and sp-bridging ligands, a strongly delocalized electron system is formed between these metallic "dopants", facilitating transport along the molecular backbone. Here, we study the influence of molecule-metal coupling on charge transport of dinuclear X(PP)2FeC4Fe(PP)2X molecular wires (PP = Et2PCH2CH2PEt2); X = CN (1), NCS (2), NCSe (3), C4SnMe3 (4), and C2SnMe3 (5) under ultrahigh vacuum and variable temperature conditions. In contrast to 1, which showed unstable junctions at very low conductance (8.1 × 10(-7) G0), 4 formed a Au-C4FeC4FeC4-Au junction 4' after SnMe3 extrusion, which revealed a conductance of 8.9 × 10(-3) G0, 3 orders of magnitude higher than for 2 (7.9 × 10(-6) G0) and 2 orders of magnitude higher than for 3 (3.8 × 10(-4) G0). Density functional theory (DFT) confirmed the experimental trend in the conductance for the various anchoring motifs. The strong hybridization of molecular and metal states found in the C-Au coupling case enables the delocalized electronic system of the organometallic Fe2 backbone to be extended over the molecule-metal interfaces to the metal electrodes to establish high-conductive molecular wires. PMID:25233125

Schwarz, Florian; Kastlunger, Georg; Lissel, Franziska; Riel, Heike; Venkatesan, Koushik; Berke, Heinz; Stadler, Robert; Lörtscher, Emanuel

2014-10-01

210

Point of collapse and continuation methods for large AC\\/DC systems  

Microsoft Academic Search

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 power systems is described. The performance of these methods is compared for real systems of up to 2158 buses. Computational details of the implementation of the PoC and continuation methods are detailed, and the unique problems

C. A. Canizares; F. L. Alvarado

1993-01-01

211

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

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

212

Test results of an automatic calibration system for ac-dc thermal voltage converters and ac voltage sources  

NASA Astrophysics Data System (ADS)

An automatic calibration system has been developed for testing ac-dc thermal voltage converters (TVC's) and ac voltage sources. Precision, repeatability, and systematic errors are investigated using the data gathered from 100 mV to 1000 V over a frequency range of 10 Hz to 1 MHz. The ac-dc difference of a TVC is determined by the least-square fit to the characteristic equation E = k(V exp n) with ac and dc inputs. A mathematical formalism incorporating the systematic errors and the ac-dc difference, or deviation, caused by the ac input source is developed for data analysis.

Fu, Chu-Min; Cohee, Art; Jaeger, Klaus B.

1986-12-01

213

Dc bias system of a 35 kV/90 MVA saturated iron core SFCL  

NASA Astrophysics Data System (ADS)

Saturated iron core superconducting fault current limiter (SIC-SFCL) is a promising fault current limiting device for high or extra-high voltage power grids. It has low impedance in normal power transmission and turns high impedance when a short-circuit takes place. The dc bias system of a saturated iron core superconducting fault current limiter plays a key role in realizing these features. Our 35 kV/90 MVA SIC-SFCL has been running live-grid since January 2008 at Puji substation in Yunnan, China. In this paper, the working principle of the dc bias system will be introduced and results of artificially imposed short-circuit tests will be provided, which verifies the validity of this system.

Sun, Yuwei; Gong, Weizhi; Wang, Jianzhong; Hong, Hui; Tian, Bo; Xin, Ying

2011-06-01

214

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

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

215

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

NASA Technical Reports Server (NTRS)

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.

Packard, D. T. (inventor)

1985-01-01

216

A one-wire battery monitoring system with applications to on-board charging for electric vehicles  

NASA Astrophysics Data System (ADS)

A on-board charge system which utilizes a one-wire system for voltage monitoring is discussed and test results obtained using the system are presented. The system consists of the following: (1) a 20 kHz high frequency charger; (2) a charge algorithm for lead-acid batteries with gelled electrolyte, such that gassing is avoided; (3) the control system to implement this charge algorithm; and (4) a one-wire battery monitoring system to provide cell/module voltage information to the battery charge controller. Prototype elements of the system have been tested and the system was installed into an EVA Pacer electric vehicle. Charge tests are performed and data taken with the system installed. All elements of the system functioned properly under user conditions. In particular, the charger demonstrated good efficiency, near unity power factor and full programmability. The charge controller functioned reliably and without flaw. The one-wire monitoring system which permits monitoring of cell/module voltages in a battery pack without an extensive conventional wire harness has proven effective and voltage measurements were taken fast enough for control of charging. It was found that for the purpose of voltage monitoring under driving conditions, the system in its present form is too slow.

Nowak, Dieter

1990-10-01

217

STUDY OF VEHICLE DYNAMIC MODELING FIDELITY ON HAPTIC COLLABORATION IN STEER-BY-WIRE SYSTEMS  

E-print Network

The Steer-By-Wire (SBW) paradigm for vehicle control offers many advantages over traditional use of mechanical steering systems but comes at the cost of loss of proprioception (“road feel”). To this end, haptic interfaces for SBW systems have been proposed to restore the intimacy of interactive control back to the driver. However, the degree of realism for the interaction is dependent on the fidelity of the underlying computational vehicle dynamics model. Hence we focus on quantitative comparative testing of the role of vehicle dynamics modeling fidelity for haptic SBW tasks. Additionally the SBW paradigm can simplify implementation of shared/collaborative control (steering) of the underlying mechanical system (vehicle). Possibilities range from sharing of control between multiple individual users or between user and automation technology. Performance evaluation of 3 modes of shared control vs. individual control of driving was carried out and preliminary analysis of results is presented in the paper. 1.

Anand P. Naik; Leng-feng Lee; Venkat N. Krovi

218

DC-ATLAS: a systems biology resource to dissect receptor specific signal transduction in dendritic cells  

PubMed Central

Background The advent of Systems Biology has been accompanied by the blooming of pathway databases. Currently pathways are defined generically with respect to the organ or cell type where a reaction takes place. The cell type specificity of the reactions is the foundation of immunological research, and capturing this specificity is of paramount importance when using pathway-based analyses to decipher complex immunological datasets. Here, we present DC-ATLAS, a novel and versatile resource for the interpretation of high-throughput data generated perturbing the signaling network of dendritic cells (DCs). Results Pathways are annotated using a novel data model, the Biological Connection Markup Language (BCML), a SBGN-compliant data format developed to store the large amount of information collected. The application of DC-ATLAS to pathway-based analysis of the transcriptional program of DCs stimulated with agonists of the toll-like receptor family allows an integrated description of the flow of information from the cellular sensors to the functional outcome, capturing the temporal series of activation events by grouping sets of reactions that occur at different time points in well-defined functional modules. Conclusions The initiative significantly improves our understanding of DC biology and regulatory networks. Developing a systems biology approach for immune system holds the promise of translating knowledge on the immune system into more successful immunotherapy strategies. PMID:21092113

2010-01-01

219

DC Circuit Powered by Orbital Motion: Magnetic Interactions in Compact Object Binaries and Exoplanetary Systems  

E-print Network

The unipolar induction DC circuit model, originally developed by Goldreich & 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 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 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 ultra-compact white dwarf binaries, we find that DC circuit does not provide adequate energy dissipation to explain the observed X-ray luminosities of seve...

Lai, Dong

2012-01-01

220

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

221

The Newton-Raphson Load Flow Applied to AC\\/DC Systems with Commutation Impedance  

Microsoft Academic Search

Existing conditions in industrial ac-dc power systems may result in significant commutation resistances. If the resistance to reactance ratio of the commutation impedance is high, significant errors can result in load-flow studies which neglect the resistive portion. A method is presented for inclusion of a resistance-inductance fed bridge rectifier in a Newton-Raphson (N-R) load flow program. Polar form of the

Daniel J. Tylavsky; Frederick C. Trutt

1983-01-01

222

Identification and adaptive neural network control of a DC motor system with dead-zone characteristics.  

PubMed

In this paper, an adaptive control approach based on the neural networks is presented to control a DC motor system with dead-zone characteristics (DZC), where two neural networks are proposed to formulate the traditional identification and control approaches. First, a Wiener-type neural network (WNN) is proposed to identify the motor DZC, which formulates the Wiener model with a linear dynamic block in cascade with a nonlinear static gain. Second, a feedforward neural network is proposed to formulate the traditional PID controller, termed as PID-type neural network (PIDNN), which is then used to control and compensate for the DZC. In this way, the DC motor system with DZC is identified by the WNN identifier, which provides model information to the PIDNN controller in order to make it adaptive. Back-propagation algorithms are used to train both neural networks. Also, stability and convergence analysis are conducted using the Lyapunov theorem. Finally, experiments on the DC motor system demonstrated accurate identification and good compensation for dead-zone with improved control performance over the conventional PID control. PMID:21788017

Peng, Jinzhu; Dubay, Rickey

2011-10-01

223

LANSCE-R WIRE-SCANNER ANALOG FRONT-END ELECTRONICS  

SciTech Connect

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.

Gruchalla, Michael E. [Los Alamos National Laboratory

2011-01-01

224

Damping of a parallel AC-DC power system using PID power system stabilizers and rectifier current regulators  

Microsoft Academic Search

A scheme for improving the dynamic stability of a parallel AC-DC power system is presented. It uses a proportional-integral-derivative (PID) power-system stabilizer and a PID rectifier current regulator to enhance the damping for the electromechanical 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

Yuan-Yih Hsu; L. Wang

1988-01-01

225

Point of collapse methods applied to ac/dc power systems  

SciTech Connect

This paper describes an extension of the Point of Collapse method developed for ac systems studies to the determination of saddle-node bifurcations in power systems including high voltage direct current (HVDC) transmission. Bus voltage profiles are illustrated for an ac/dc test system, which significantly differ from the profiles of pure ac systems for typical system models. In particular, voltage dependent current order limits (VDCOLs) are shown to affect the voltage profiles (nose curves) and the loadability margin of the system. It is also shown that Hopf bifurcations, which are not possible in purely ac lossless systems with second-order generator models, become plausible when the dynamics for the HVDC system are included.

Canizares, C.A.; Alvarado, F.L.; DeMarco, C.L.; Dobson, I.; Long, W.F. (Wisconsin Univ., Madison, WI (United States))

1992-05-01

226

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

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

227

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

SciTech Connect

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.

Mueller-Huelsbeck, Stefan, E-mail: muehue@diako.d [Academic Teaching Hospitals Flensburg, Department of Diagnostic and Interventional Radiology/Neuroradiology (Germany); Huemme, Tim H.; Philipp Schaefer, J.; Charalambous, Nikolas [University Hospitals Schleswig-Holstein-Campus Kiel, Department of Radiology (Germany); Paulsen, Friedrich [University of Erlangen-Nuernberg, Department of Anatomy II (Germany); Heller, Martin; Jahnke, Thomas [University Hospitals Schleswig-Holstein-Campus Kiel, Department of Radiology (Germany)

2010-12-15

228

Evaluation of CWMS (Continuous-Wave Measurement System) single-wire dipole antenna  

NASA Astrophysics Data System (ADS)

The Numerical Electromagnetics Code (NEC) was used to model a single-wire horizontal dipole antenna used with the FCDNA Continuous-Wave Measurement System (CWMS). Line drawings and construction information were supplied to LLNL staff by FCDNA and EGG personnel, and NEC models were developed accordingly. Data were obtained from NEC describing all components of the electric and magnetic fields at nine different field-strength measurement points, as well as the input impedance at the antenna feed-point. Thirteen frequencies were used in the model, ranging all the way from 10 kHz to 100 MHz. In addition, the antenna was examined in two configurations, with and without a coaxial transmission line which extended from the feed-point balun to ground level.

Breakall, J. K.; Christman, A. M.

1987-11-01

229

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

SciTech Connect

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.

Kennth Marken

2006-08-11

230

Hardware model of a shipboard zonal electrical distribution system (ZEDS) : alternating current/direct current (AC/DC)  

E-print Network

A hardware model of a shipboard electrical distribution system based on aspects of the DDG 51 Flight IIA, Arleigh Burke class, 60Hz Alternating Current (AC) and the future direct current (DC), zonal electrical distribution ...

Tidd, Chad N. (Chad Norman)

2010-01-01

231

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

NASA Technical Reports Server (NTRS)

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.

Appelbaum, J.; Singer, S.

1989-01-01

232

Wire core reactor for NTP  

NASA Technical Reports Server (NTRS)

The development of the wire core system for Nuclear Thermal Propulsion (NTP) that took place from 1963 to 1965 is discussed. A wire core consists of a fuel wire with spacer wires. It's an annular flow core having a central control rod. There are actually four of these, with beryllium solid reflectors on both ends and all the way around. Much of the information on the concept is given in viewgraph form. Viewgraphs are presented on design details of the wire core, the engine design, engine weight vs. thrust, a technique used to fabricate the wire fuel element, and axial temperature distribution.

Harty, R. B.

1991-01-01

233

An accurate AC-Dc voltage transfer standard test system using the differential and the dual-channel method  

Microsoft Academic Search

In the Electrotechnical Laboratory (ETL) the accuracy of the AC-DC voltage transfer difference was improved for the voltage range of 1-20 V in the frequency range from 10 Hz to 100 kHz. At the same time, the AC-Dc transfer standards and the measurement system which is used in the Japan Electric Meter Inspection Corporation (JEMIC) were also improved. The system

K. Takahashi; H. Sasaki; M. Klonz; T. Endo

1993-01-01

234

Mathematical model for the dc-ac inverter for the Space Shuttle  

NASA Technical Reports Server (NTRS)

The reader is informed of what was done for the mathematical modeling of the dc-ac inverter for the Space Shuttle. The mathematical modeling of the dc-ac inverter is an essential element in the modeling of the electrical power distribution system of the Space Shuttle. The electrical power distribution system which is present on the Space Shuttle is made up to 3 strings each having a fuel cell which provides dc to those systems which require dc, and the inverters which convert the dc to ac for those elements which require ac. The inverters are units which are 2 wire structures for the main dc inputs and 2 wire structures for the ac output. When 3 are connected together a 4 wire wye connection results on the ac side. The method of modeling is performed by using a Least Squares curve fitting method. A computer program is presented for implementation of the model along with graphs and tables to demonstrate the accuracy of the model.

Berry, Frederick C.

1987-01-01

235

Control of Current-Source Active Power Filter using Unit Vector Template in Three Phase Four Wire Unbalnced System  

Microsoft Academic Search

In recent years there has been considerable interest in the development and application of active power filters using current source active power filters for harmonic filtering. The unbalanced load resulting zero sequence current can affect the performance of shunt active filter adversely. In this paper a novel active, filter control for a three-phase four-wire unbalance system has been designed. This

K. Vadirajacharya; P. Agarwal; H. O. Gupta

2007-01-01

236

Neural learning algorithm based power quality enhancement for three phase three wire distribution system utilizing shunt active power filter strategy  

Microsoft Academic Search

This paper explores the application of artificial intelligence on solving the power quality problems by using the shunt active power filter strategy for three phase three wire distribution system. The unit vector template generation control technique is modeled as current controller for the shunt active power filter strategy. The proportional and integral (PI) controller is designed to minimize error between

A. Senthil Kumar; P. Ajay-D-Vimal Raj

2011-01-01

237

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

NASA Technical Reports Server (NTRS)

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.

Lebron, Ramon C.

1992-01-01

238

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

NASA Technical Reports Server (NTRS)

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.

Lebron, Ramon C.

1992-01-01

239

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

SciTech Connect

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.

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

2008-01-23

240

Nanograin VO2 in the metal phase: a plasmonic system with falling dc resistivity as temperature rises  

NASA Astrophysics Data System (ADS)

Thin films of vanadium dioxide with grain sizes smaller than 60 nm have a metallic phase with excellent plasmonic response, but their dc resistivity falls as temperature rises to values well above the metal-insulator transition. At the transition optical switching is complete, but the switch in dc resistance is incomplete. In the metallic phase, nanograin and large grain samples have similar values of both plasma frequency and relaxation rate. However, plasmonic response in nanograins is stronger due to the absence of a low energy interband transition found in large grain films. Conductivity rises with thermal activation energy of 108 meV, which is well below that in the semiconductor phase. Possible mechanisms for 'non-metal-like' dc behaviour in this plasmonic system are briefly discussed. They include fluctuations, which are coherent in nanograins but incoherent for larger grains. Nanoscale systems seem preferable for optical switching applications and large grain structures for dc switching work.

Gentle, A.; Maaroof, A. I.; Smith, G. B.

2007-01-01

241

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

PubMed

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

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

2012-02-01

242

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)

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.

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

2012-02-01

243

A Stabilization of Frequency Oscillations in a Parallel AC-DC Interconnected Power System via an HVDC Link  

Microsoft Academic Search

This paper presents a new application of High Voltage Direct Current (HVDC) link to stabilization of frequency oscillations in a parallel AC-DC interconnected power system. When an interconnected AC power system is subjected to a large load with rapid change, system frequency may be considerably disturbed and becomes oscillatory. By utilizing the system interconnections as the control channels of HVDC

Issarachai Ngamroo

2002-01-01

244

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

SciTech Connect

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.

Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W. [High Voltage Engineering Europa B.V., P.O. Box 99, 3800 AB, Amersfoort (Netherlands)

2013-04-19

245

DC Circuit Powered by Orbital Motion: Magnetic Interactions in Compact Object Binaries and Exoplanetary Systems  

E-print Network

The unipolar induction DC circuit model, originally developed by Goldreich & 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 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 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 ultra-compact white dwarf binaries, we find that DC circuit 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, magnetic torque and dissipation are negligible, except possibly during the early T Tauri phase, when the stellar magnetic field is stronger than 10^3G.

Dong Lai

2012-06-17

246

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

247

Plant flavonoids target Pseudomonas syringae pv. tomato DC3000 flagella and type III secretion system.  

PubMed

Flavonoids are among the most abundant plant secondary metabolites involved in plant protection against pathogens, but micro-organisms have developed resistance mechanisms to those compounds. We previously demonstrated that the MexAB-OprM efflux pump mediates resistance of Pseudomonas syringae pv. tomato (Pto) DC3000 to flavonoids, facilitating its survival and the colonization of the host. Here, we have shown that tomato plants respond to Pto infection producing flavonoids and other phenolic compounds. The effects of flavonoids on key traits of this model plant-pathogen bacterium have also been investigated observing that they reduce Pto swimming and swarming because of the loss of flagella, and also inhibited the expression and assembly of a functional type III secretion system. Those effects were more severe in a mutant lacking the MexAB-OprM pump. Our results suggest that flavonoids inhibit the function of the GacS/GacA two-component system, causing a depletion of rsmY?RNA, therefore affecting the synthesis of two important virulence factors in Pto DC3000, flagella and the type III secretion system. These data provide new insights into the flavonoid role in the molecular dialog between host and pathogen. PMID:24249293

Vargas, Paola; Farias, Gabriela A; Nogales, Joaquina; Prada, Harold; Carvajal, Vivian; Barón, Matilde; Rivilla, Rafael; Martín, Marta; Olmedilla, Adela; Gallegos, María-Trinidad

2013-12-01

248

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

NASA Astrophysics Data System (ADS)

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.

Wang, Minjuan; Liu, Hong; Fu, Yuming

249

An EEG (electroencephalogram) recording system with carbon wire electrodes for simultaneous EEG-fMRI (functional magnetic resonance imaging) recording  

PubMed Central

Simultaneous EEG-fMRI (Electroencephalography-functional Magnetic Resonance Imaging) recording provides a means for acquiring high temporal resolution electrophysiological data and high spatial resolution metabolic data of the brain in the same experimental runs. Carbon wire electrodes (not metallic EEG electrodes with carbon wire leads) are suitable for simultaneous EEG-fMRI recording, because they cause less RF (radio-frequency) heating and susceptibility artifacts than metallic electrodes. These characteristics are especially desirable for recording the EEG in high field MRI scanners. Carbon wire electrodes are also comfortable to wear during long recording sessions. However, carbon electrodes have high electrode-electrolyte potentials compared to widely used Ag/AgCl (silver/silver-chloride) electrodes, which may cause slow voltage drifts. This paper introduces a prototype EEG recording system with carbon wire electrodes and a circuit that suppresses the slow voltage drift. The system was tested for the voltage drift, RF heating, susceptibility artifact, and impedance, and was also evaluated in a simultaneous ERP (event-related potential)-fMRI experiment. PMID:18588913

Negishi, Michiro; Abildgaard, Mark; Laufer, Ilan; Nixon, Terry; Constable, Robert Todd

2008-01-01

250

The failure of DFT computations for a stepped-substrate-supported monatomic highly-correlated wire system  

NASA Astrophysics Data System (ADS)

The ab-initio method, density functional theory (DFT), has been immensely successful in its ability to predict physical properties of condensed matter systems. In particular, DFT calculations have proven to be quantitatively accurate in predicting structural properties in a wide range of materials and qualitative failures are rare. Here, however, we show that DFT can fail qualitatively to correctly predict the dimerized structural phase for a recently reported experimentally realized monatomic Co wire system that is self-assembled on a vicinal, i.e. stepped, Cu(111) substrate [1]. We attribute this failure to DFT's over-prediction of hybridization of the Co wire with the underlying Cu substrate. We demonstrate that this over-hybridization leads to weakening of the magnetic coupling along the wire, which is responsible for dimerization, while increasing the stiffness of the wire due to strengthening of the non-magnetic elastic term. Additionally, we show that accounting for local interactions via DFT+U also fails at predicting the correct structural phase. [1] N. Zaki et al, arXiv:1208.0612 (2012)

Zaki, Nader; Osgood, Richard M.; Millis, Andrew J.; Marianetti, Chris A.

2013-03-01

251

Photovoltaic-Battery-Powered DC Bus System for Common Portable Electronic Devices  

Microsoft Academic Search

Renewable energy sources based on photovoltaic (PV) along with battery-based energy storage necessitate power conditioning to meet load requirements and\\/or be connected to the electrical grid. The power conditioning is achieved via a dc-dc converter and a DC-AC inverter stages to produce the desired AC source. This is also the case even when the load is of dc type, such

Dylan Dah-Chuan Lu; Vassilios G. Agelidis

2009-01-01

252

Analysis of system wide distortion in an integrated power system utilizing a high voltage DC bus and silicon carbide power devices  

E-print Network

This research investigates the distortion on the electrical distribution system for a high voltage DC Integrated Power System (IPS). The analysis was concentrated on the power supplied to a propulsion motor driven by an ...

Fallier, William F. (William Frederick)

2007-01-01

253

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

NASA Technical Reports Server (NTRS)

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.

Schwarze, G. E.

1985-01-01

254

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

SciTech Connect

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 the 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 includes 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.

Schwarze, G.E.

1994-09-01

255

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

NASA Technical Reports Server (NTRS)

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.

1991-01-01

256

Research on an X-ray non-destructive testing system for conveyer belt with steel wire ropes  

Microsoft Academic Search

The thesis conducts a deep research on an X-ray non-destructive testing system for the conveyer belt with steel wire ropes, and proposes the detailed design program. By researching the image processing algorithm of the conveyer belt, the research realized the marginal check, joint elongation check and breakdown location. Meanwhile, a system software was developed by using the C#.NET programming design

Ye Chunqing; Miao Changyun

2010-01-01

257

Intelligent dc-dc Converter Technology Developed and Tested  

NASA Technical Reports Server (NTRS)

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.

Button, Robert M.

2001-01-01

258

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

NASA Astrophysics Data System (ADS)

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.

Matsushima, Toshio

259

Wire chamber  

DOEpatents

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.

Atac, Muzaffer (Wheaton, IL)

1989-01-01

260

Development of the electronic control unit for the rack-actuating steer-by-wire using the hardware-in-the-loop simulation system  

Microsoft Academic Search

The steer-by-wire (SBW) system in a passenger car substitutes the typical mechanical linkage between the steering wheel and the front wheel with electric wires. The control conception of the rack-actuating SBW system was proposed in this paper. Basically, the controller should compensate for a conventional steering system composed of mechanical linkages. The hardware-in-the-loop-simulation (HILS) system was developed for the electronic

Tong-Jin Park; Chang-Soo Han; Sang-Ho Lee

2005-01-01

261

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

SciTech Connect

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.

Canizares, C.A. (Escuela Politecnica Nacional, Quito (Ecuador)); Alvarado, F.L. (Univ. of Wisconsin, Madison, WI (United States))

1993-02-01

262

Experimental Analysis of Voltage Drop Compensation in a DC Electrified Railway by Introducing an Energy Storage System Incorporating EDLCs  

NASA Astrophysics Data System (ADS)

Interest has been shown in the concept of an energy storage system aimed at leveling load and improving energy efficiency by charging during vehicle regeneration and discharging during running. Such a system represents an efficient countermeasure against pantograph point voltage drop, power load fluctuation and regenerative power loss. We selected an EDLC model as an energy storage medium and a step-up/step-down chopper as a power converter to exchange power between the storage medium and overhead lines. Basic verification was conducted using a mini-model for DC 400V, demonstrating characteristics suitable for its use as an energy storage system. Based on these results, an energy storage system was built for DC 600V and a verification test conducted in conjunction with the Enoshima Electric Railway Co. Ltd. This paper gives its experimental analysis of voltage drop compensation in a DC electrified railway and some discussions based on the test.

Konishi, Takeshi; Hase, Shin-Ichi; Nakamichi, Yoshinobu; Nara, Hidetaka; Uemura, Tadashi

263

Towards plant wires  

E-print Network

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.

Adamatzky, Andrew

2014-01-01

264

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

ERIC Educational Resources Information Center

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…

Fox, Mark

2009-01-01

265

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

NASA Astrophysics Data System (ADS)

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.

Saito, Tatsuhito; Kondo, Keiichiro; Koseki, Takafumi

266

DC–DC Converter Technologies for On-Chip Distributed Power Supply Systems – 3D Stacking and Hybrid Operation  

Microsoft Academic Search

\\u000a Recently System-on-a-Chip (SoC) and System-in-a-Package (SiP) are getting more and more interest as major integration technologies.\\u000a They are often used to integrate various types of circuit blocks from processors and memories to analog circuits. Each block\\u000a demonstrates a different optimal supply voltage (VDD) and the difference tends to increase as the technology scales down.\\u000a For example, memory and analog circuits

Makoto Takamiya; Koichi Onizuka; Koichi Ishida; Takayasu Sakurai

267

Performance of Voltage and Frequency Controller in Isolated Wind Power Generation for a Three-Phase Four-Wire System  

Microsoft Academic Search

This paper deals with a new control algorithm for a voltage and frequency controller (VFC) of an isolated wind energy conversion system (IWECS) using an isolated asynchronous generator to feed three-phase four-wire consumer loads. The reference source currents are estimated for the indirect current control of a voltage source converter (VSC) using the single-phase PQ theory to control the voltage

Shailendra Sharma; Bhim Singh

2011-01-01

268

Comparison of Control Strategies for Shunt Active Power Filters in Three-Phase Four-Wire Systems  

Microsoft Academic Search

Strategies for extracting the three-phase reference currents for shunt active power filters are compared, evaluating their performance under different source and load conditions with the new IEEE Standard 1459 power definitions. The study was applied to a three-phase four-wire system in order to include imbalance. Under balanced and sinusoidal voltages, harmonic cancellation and reactive power compensation can be attained in

María Isabel Milanés Montero; Enrique Romero Cadaval; Fermín Barrero González

2007-01-01

269

Study of maximum power tracking techniques and control of DC\\/DC converters for photovoltaic power system  

Microsoft Academic Search

As the electric power supplied by solar arrays depends on the insolation, temperature and array voltage, it is necessary to control the operating points to draw the maximum power of the solar array. The object of this paper is to investigate the maximum power tracking algorithms which were often used to compare the tracking efficiencies for the system operating under

Chihchiang Hua; Chihming Shen

1998-01-01

270

Real time state estimation of multi-converter DC power electronic systems using generalized state space averaging method  

Microsoft Academic Search

This paper presents a real time state estimation algorithm for control and security maintenance of multi-converter DC power electronic systems. Estimation of the state variables of the system includes the effects of ripples and converter switching actions. The proposed state estimator is based on the weighted least squares (WLS) approach. Generalized state space averaging technique in which we consider the

A. Emadi; A. Abur

2002-01-01

271

Wire Wise.  

ERIC Educational Resources Information Center

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)

Swanquist, Barry

1998-01-01

272

Stretching Wires  

NSDL National Science Digital Library

In this activity, learners determine the elastic and plastic properties of different types of metal wires. Learners discover that wires of the same gauge, but made of different metals, typically support different loads (masses) before going through the elastic to plastic transition. Learners also learn the difference between elastic deformation, which is recoverable after the load is removed, and plastic deformation, which is not recoverable. Note: one way to save time on this lab is to have different groups test different metals.

Urbana-Champaign, University O.

2013-01-04

273

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

274

Direct Current Measurement Based Steer-By-Wire Systems for Realistic Driving Feeling  

E-print Network

, and less injury in case of car accidents. However, there are also numbers of disadvantages due to the lack given by a driver is transmitted to the road wheels through electrical wires while this signal several advantages such as lager space in the cabin, freedom in car interior design, no oil leaking

Ryu, Jee-Hwan

275

Asymmetric and double-cathode-pad wire chambers for the LHCb muon system  

NASA Astrophysics Data System (ADS)

We present results from two types of Multi-Wire Proportional Chambers (MWPCs) with wire pitch of 1.5 mm and cathode-cathode distance of 5 mm intended for triggering purposes in the LHCb experiment. Both prototypes use cathode readout because this allows arbitrary segmentation in order to achieve the required granularity. One MWPC prototype uses a symmetric wire-cathode distance (2.5/2.5 mm) with double cathode readout, which doubles the signal compared to reading only one cathode. The second prototype uses an asymmetric wire-cathode distance (1.25/3.75 mm) with single cathode readout which also doubles the signal and in addition reduces the width of the induced charge distribution and therefore reduces the crosstalk for small cathode pads. We also performed a dedicated optimization of readout traces and guard traces in order to reduce the pad-pad crosstalk. Both prototypes show a few hundred volts of operating plateau defined as the region with 99% efficiency in a 20 ns time window. Close to the plateau end, a time resolution of better than 3 ns was achieved.

Kachtchouk, A.; Lippmann, C.; Riegler, W.; Schmidt, B.; Schneider, T.; Souvorov, V.

2005-12-01

276

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

277

Preparation of high-quality hydrogenated amorphous silicon film with a new microwave electron cyclotron resonance chemical vapour deposition system assisted with hot wire  

Microsoft Academic Search

The preparation of high-quality hydrogenated amorphous silicon (a-Si:H) film with a new microwave electron cyclotron resonance-chemical vapour deposition (MWECR-CVD) system assisted with hot wire is presented. In this system the hot wire plays an important role in perfecting the microstructure as well as improving the stability and the optoelectronic properties of the a-Si:H film. The experimental results indicate that in

Xiu-Hong Zhu; Guang-Hua Chen; Sheng-Yi Yin; Yan-Dong Rong; Wen-Li Zhang; Yue-Hui Hu

2005-01-01

278

DC Circuit Powered by Orbital Motion: Magnetic Interactions in Compact Object Binaries and Exoplanetary Systems  

NASA Astrophysics Data System (ADS)

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 103 G.

Lai, Dong

2012-09-01

279

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

280

International Conference on Dependable Systems & Networks: Washington, DC, 23-26 June 2002. Masquerade Detection Using Truncated Command Lines  

E-print Network

session, cumulative CPU time, partic- ular programs executed, names of files accessed, user com- mandsInternational Conference on Dependable Systems & Networks: Washington, DC, 23-26 June 2002 advantage of the le- gitimate user's privileges and access to programs and data. The interloper's commands

Maxion, Roy

281

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

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

282

Power management strategies of a DC-coupled hybrid power system in a microgrid for decentralized generation  

Microsoft Academic Search

A classical wind energy conversion system is usually a passive generator. Its power does not depend on the grid requirement, but entirely on the fluctuant wind condition. In this paper a DC-coupled wind\\/hydrogen\\/super-capacitor hybrid power system is studied. The purpose of the control system is to coordinate these different sources, especially their power exchange, in order to make the generated

Tao Zhou; Peng Li; Bruno FRANCOIS

2009-01-01

283

Power boundaries in multifunctional converter control for three-phase four-wire systems  

Microsoft Academic Search

It has been established that a voltage source converter when used as a power quality compensator can be used for bidirectional active power exchange across the dc bus, simultaneously. However, it may not be possible to execute all the tasks together to their fullest requirements, if the converter operation is restricted within a specified kVA rating. To ensure the safety

Rajendra R. Sawant; M. C. Chandorkar

2008-01-01

284

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

285

Clinical percutaneous imaging of coronary anatomy using an over-the-wire ultrasound catheter system  

Microsoft Academic Search

This manuscript describes initial applications of a unique new intravascular ultrasound imaging catheter. This 5.5F catheter uses an over-the-wire design and incorporates a phased array transducer at its tip. There are no moving parts. A 360° image is produced perpendicular to the catheter axis using a 20 MHz center frequency. A dedicated minicomputer is used for initial image processing, as

J. B. Hodgson; S. P. Graham; A. D. Savakus; S. G. Dame; D. N. Stephens; P. S. Dhillon; D. Brands; H. Sheehan; M. J. Eberle

1989-01-01

286

A Model System for Dimensional Competition in Nanostructures: A Quantum Wire on a Surface  

PubMed Central

The retarded Green’s function (E?H + i?)?1is given for a dimensionally hybrid Hamiltonian which interpolates between one and two dimensions. This is used as a model for dimensional competition in propagation effects in the presence of one-dimensional subsystems on a surface. The presence of a quantum wire generates additional exponential terms in the Green’s function. The result shows how the location of the one-dimensional subsystem affects propagation of particles.

2008-01-01

287

Early Oscillation Detection for DC/DC Converter Fault Diagnosis  

NASA Technical Reports Server (NTRS)

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.

Wang, Bright L.

2011-01-01

288

Voltage and Frequency Control for a Self-Excited Induction Generator Using a Three-Phase Four-Wire Electronic Converter  

Microsoft Academic Search

This work proposes a system, based on a self-excited induction generator (SEIG) with a shunt electronic converter, to feed isolated three-phase and single-phase linear or nonlinear loads. The electronic converter is composed by a three-phase four-wire shunt active filter and a DC chopper attached to its DC bus. The converter compensates the current harmonics, the reactive power and the load

JoseAntonio Barrado; R. Grino

2006-01-01

289

Superconducting wires  

Microsoft Academic Search

The requirement of high critical current density has prompted extensive research on ceramic processing of high-T sub c superconductors. An overview of wire fabrication techniques and the limitations they impose on component design will be presented. The effects of processing on microstructure and critical current density will also be discussed. Particle alignment has been observed in extruded samples which is

M. T. Lanagan; R. B. Poeppel; J. P. Singh; D. I. Dossantos; J. K. Lumpp; J. T. Dusek; K. C. Goretta

1988-01-01

290

Flying wires at Fermilab  

SciTech Connect

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.

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

1989-03-01

291

Modeling and simulation of a DC motor control system with digital PID controller and encoder in FPGA using Xilinx system generator  

Microsoft Academic Search

This paper presents a novel method for design and simulation of a DC motor closed loop control system in Field Programmable Gate Array device (FPGA). The digital designed PID controller is more advanced, beneficial and therefore produces a better response, as compared to the analog PID with velocity measurement. It can be implemented on system-on-chip devices easily. MATLAB Xilinx system

Behzad Behnam; Masoud Mansouryar

2011-01-01

292

A Simplified Cascade Current Source Inverter Interconnected to Single-Phase Three-Wire Distribution System and Its Application to Electric Energy Storage System with Batteries  

Microsoft Academic Search

A novel current source inverter system interconnected to the single-phase grid is proposed. It has the same construction as the conventional three-phase current source inverter that is interconnected to the single-phase three-wire distribution system. Though the proposed circuit has no output transformer, it can be equivalently performed as the single-phase double cascade inverter by diverting the pole transformer in the

Syuichi Iwata; Shigeo Masukawa; Shoji Iida

2004-01-01

293

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

Code of Federal Regulations, 2013 CFR

... All building and electrical codes applicable in...of the 1978 National Electrical Code, entitled Communications...5) Limitations on electrical signals. Only signal...on individual wiring conductors shall be limited to...Capacity of PVC Insulated Copper Wire, Confined...

2013-10-01

294

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

Code of Federal Regulations, 2011 CFR

... All building and electrical codes applicable in...of the 1978 National Electrical Code, entitled Communications...5) Limitations on electrical signals. Only signal...on individual wiring conductors shall be limited to...Capacity of PVC Insulated Copper Wire, Confined...

2011-10-01

295

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

Code of Federal Regulations, 2010 CFR

... All building and electrical codes applicable in...of the 1978 National Electrical Code, entitled Communications...5) Limitations on electrical signals. Only signal...on individual wiring conductors shall be limited to...Capacity of PVC Insulated Copper Wire, Confined...

2010-10-01

296

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

Code of Federal Regulations, 2012 CFR

... All building and electrical codes applicable in...of the 1978 National Electrical Code, entitled Communications...5) Limitations on electrical signals. Only signal...on individual wiring conductors shall be limited to...Capacity of PVC Insulated Copper Wire, Confined...

2012-10-01

297

DC-DC powering for the CMS pixel upgrade  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

298

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

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

299

The Geostationary Operational Satellite R Series SpaceWire Based Data System Architecture  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

300

46 CFR 111.60-11 - Wire.  

Code of Federal Regulations, 2011 CFR

...60-11 Section 111.60-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-11 Wire....

2011-10-01

301

46 CFR 111.60-11 - Wire.  

Code of Federal Regulations, 2012 CFR

...60-11 Section 111.60-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-11 Wire....

2012-10-01

302

46 CFR 111.60-11 - Wire.  

Code of Federal Regulations, 2010 CFR

...60-11 Section 111.60-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-11 Wire....

2010-10-01

303

A Wire Position Monitor System for the 1.3 GHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator  

E-print Network

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 ~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 cool down, and during further testing. As the measurement system offers a high resolution, we also discuss options for use as a vibration detector.

Eddy, N; Prieto, P; Semenov, A; Voy, D C; Wendt, M

2012-01-01

304

Aircraft wiring program status report  

NASA Astrophysics Data System (ADS)

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.

Beach, Rex

1995-11-01

305

Aircraft wiring program status report  

Microsoft Academic Search

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.

Rex Beach

1995-01-01

306

Aircraft wiring program status report  

NASA Technical Reports Server (NTRS)

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.

Beach, Rex

1995-01-01

307

Flat Wire  

NASA Technical Reports Server (NTRS)

The N.Y. State Urban Development Corp., Amp Inc., and Western Electric Corp. are working with NASA to produce flat conductor electrical cable. Flat conductor electrical cable originally designed for spacecraft by the Marshall Space Flight Center, has been installed in a housing project. Because it is very thin the wire can be mounted on surfaces of walls and floors instead of inside of them. Installation costs reduced significantly due to single installation time.

1976-01-01

308

An in vitro comparison between a bonded retainer system and a directly bonded flexible spiral wire retainer.  

PubMed

Bonded lingual retainers are becoming more popular to stabilize the results of orthodontic treatment. The in vitro shear strength of a flexible spiral wire (FSW) retainer (Zachrisson, 1977, 1983) bonded with Prisma Fil was compared to the 'A'-Company bonded lingual retainer system, bonded with either Concise or Right-On, to human enamel. Statistical analysis of the results showed no significant differences between the 'A'-Company system when bonded with Concise or Right On, Concise having a greater mean bond strength, but also a greater range of bond strength values. All the materials tested gave bond strengths that were adequate for clinical practice and it is concluded that the choice of bonded retainer system can be made upon grounds of clinical convenience or cost. PMID:7781723

Bryan, D C; Sherriff, M

1995-04-01

309

IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 7, NO. 2, MAY 1992, PP. 673 683. POINT OF COLLAPSE METHODS APPLIED TO AC DC POWER SYSTEMS  

E-print Network

to determine the distance in state space to the point of collapse, so that better estimates of the loadabilityIEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 7, NO. 2, MAY 1992, PP. 673 683. POINT OF COLLAPSE METHODS APPLIED TO AC DC POWER SYSTEMS Claudio A. Ca~nizares Fernando L. Alvarado Christopher L. DeMarco Ian

Cañizares, Claudio A.

310

Brushless DC motor drives supplied by PV power system based on Z-source inverter and FLIC MPPT controller  

Microsoft Academic Search

This paper discusses operation performance of a water pumping system consist of a brushless dc (BLDC) motor coupled a centrifugal pump and accompanying a Z-source inverter (ZSI) fed by a photovoltaic (PV) array, to be improved. Despite conventional double-stage power converters, this paper proposes utilizing a single-stage ZSI to extract the maximum power of the PV array and supply the

S. A. K. H. Mozaffari Niapour; S. Danyali; M. B. B. Sharifian; M. R. Feyzi

2011-01-01

311

Design and Implementation of a Fully Digital DC Servo System Based on a Single-Chip Microcomputer  

Microsoft Academic Search

A single-chip microcomputer is used to design a fully digital dc servo system to replace the conventional analog circuits. This microcomputer performs three main tasks: the firing control of a three-phase full-wave thyristor dual converter; the compensation for the nonlinear and loading effect in the converter; and compensations of position loop and rate loop. With no current feedback and minimum

Pei-Chong Tang; Shui-Shong Lu; Yung-Chun Wu

1982-01-01

312

Novel AC-DC\\/DC-AC, DC-AC\\/AC-DC and AC-AC macrocommutators for intelligent main battle tank propulsion and dispulsion  

Microsoft Academic Search

One of the trends in integrated high- and medium-power electronics (macroand mesoelectronics) in transportation is towards novel AC-DC\\/DC-AC, DC-AC\\/AC-DC and AC-AC macrocommutators for electrically-powered and mechatronically-controlled intelligent main battle tank propulsion and dispulsion spheres, incorporating two automotive gas turbo- autoabsorb- or autodriveable flywheels that are based on the Fijalkowski turbine boosting system with the brushless AC commutatorless or AC-DC\\/DC-AC macrocommutator

Bogdan T. Fijalkowski

1996-01-01

313

Non-contact measurement of dc voltages using nonlinear elements  

NASA Astrophysics Data System (ADS)

In this work, it is shown that dc voltages may be measured via a capacitive interface, provided that the capacitance between the measurement system and the dc voltage source being measured is nonlinearized. This nonlinearization is achieved by the addition of a nonlinear capacitor in series with the coupling capacitance. Two types of nonlinear capacitor are used—multilayer ceramics and varicap diodes. Currently available multilayer ceramics have a larger value than desired but prove the concept, while the small capacitance of the varicap diode allows measurement on real wires. Results show that over a low voltage range (-8 V to +8 V), the voltage on a conductor can be measured if the coupling capacitance between source and electrode is larger than 20 pF, which equates to an electrode length of 5 cm when wire compliant with MIL-W-81044-22 is used. Detection is performed by momentarily applying a voltage at a node within the measurement system, then measuring the time it takes for this voltage to decay to a threshold level—the capacitive nonlinearity causes this time delay to be dependent upon the dc input voltage whose value is being measured.

McKenzie, G.; Record, P.

2012-04-01

314

A Five-Phase Brushless DC-Machine Direct Drive System EPE Journal Vol. 14 no  

E-print Network

applications where high perfor- mance and reliability are required (such as EV, HEV, aerospace, ship propulsion implementation of a high-torque, low- speed, multiphase, permanent magnet, brushless dc-machine. The paper of phases yield a smaller magnetic yoke and decreased volume and weight. However, the number of poles

Simões, Marcelo Godoy

315

A novel approach to modeling and identifying the double loop DC motor driving system in soccer robots  

NASA Astrophysics Data System (ADS)

Using double loop DC motor drive system (DLM) of the RoboCup middle size robots as research subject, the model of DLM has been reduced to a simple state space one by the "quasi-equivalent" modeling method, based on the characteristic analysis of the system. Further, the parameters of the model can be exactly identified applying the improved genetic algorithm. The results of compared experiment proved that using this model and identification ways can get a reasonably structural and high parameters precision model. The model can describe the DLM to design the control system for robot soccer.

Li, Yonglong; Li, Zushu; Li, Jun; Wang, Niu

2007-12-01

316

The low level radio frequency control system for DC-SRF photo-injector at Peking University  

E-print Network

A low level radio frequency (LLRF) control system is designed and constructed at Peking University, which is for the DC-SRF photo injector operating at 2K. Besides with continuous wave (CW), the system is also reliable with pulsed RF and pulsed beam, the stability of amplitude and phase can achieve 0.13% and 0.1{\\deg}respectively. It is worth noting that the system works perfectly when the cavity is driven at both generator driven resonator (GDR) and self-excited loop (SEL), the latter is useful in measuring the performance of the cavity.

Wang, Fang; Lin, Lin; Hao, Jiankui; Quan, Shengwen; Zhang, Baocheng; Liu, Kexin

2014-01-01

317

DC Electronics  

NSDL National Science Digital Library

This is a website with many learning objects on DC Electronics with over 60 lessons in areas including: Basic Concepts, Electrical Circuits / Meters, Ohm's Law, Magnetism, Parallel Circuits, Series/Parallel Circuits, Series/Parallel Applications and Series Circuits.

2012-10-18

318

NEMA wire and cable standards development programs  

NASA Technical Reports Server (NTRS)

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.

Baird, Robert W.

1994-01-01

319

Welding wire pressure sensor assembly  

NASA Technical Reports Server (NTRS)

The present invention relates to a device which is used to monitor the position of a filler wire relative to a base material being welded as the filler wire is added to a welding pool. The device is applicable to automated welding systems wherein nonconsumable electrode arc welding processes are utilized in conjunction with a filler wire which is added to a weld pool created by the electrode arc. The invention senses pressure deviations from a predetermined pressure between the filler wire and the base material, and provides electrical signals responsive to the deviations for actuating control mechanisms in an automatic welding apparatus so as to minimize the pressure deviation and to prevent disengagement of the contact between the filler wire and the base material.

Morris, Timothy B. (inventor); Milly, Peter F., Sr. (inventor); White, J. Kevin (inventor)

1994-01-01

320

Radiation effects on DC-DC Converters  

NASA Technical Reports Server (NTRS)

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).

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

2000-01-01

321

An energy-efficient low voltage DC grid powered smart LED lighting system  

Microsoft Academic Search

Inefficiency of the common lightings like incandescent, fluorescent and halogen lamps presents an ample opportunity to retrofit high efficacy, long life-time and low maintenance LED solid-state lighting, which has significantly reduced in cost on an annual basis. LED lights and many electronic loads used within in-built environment are DC in nature. As such, in this paper, an energy-efficient low voltage

L. H. Koh; Yen Kheng Tan; Z. Z. Wang; King Jet Tseng

2011-01-01

322

DC-bus voltage optimum control of three-phase shunt active filter system  

Microsoft Academic Search

The aim of this paper is to identify an optimum control strategy of three-phase shunt active filters to minimize the total harmonic distortion factor of the supply current. Some design aspects starting from power that must be compensated are taken into consideration. The DC-bus capacitor operation has been simulated using Matlab-Simulink environment and the results are very interesting. It is

Alexandru Bitoleanu; Mihaela Popescu; Mircea Dobriceanu; Felicia Nastasoiu

2010-01-01

323

Modeling of a supersonic DC plasma torch system for carbon nanotube production  

NASA Astrophysics Data System (ADS)

The carbon nanotube (CNT) structure forms a very promising source material. It has unique properties such as high thermal and electrical conductivities, and a very high mechanical strength. In recent years, researchers were able to improve both the quantity and quality of the CNT production. Among the efforts made to scale up the production, Harbec and Meunier designed a new plasma torch process for the industrial production of CNT in bulk powder form. Their process is based on the DC plasma-jet pyrolysis of a carbon-containing gas. Experiments were conducted using either 100 slpm of argon or 225 slpm of helium. Tetrachloroethylene (C2Cl4, or TCE) was selected as the carbon raw material. The present work focuses on the modeling of this CNT synthesis process and aims at an understanding of the physical and chemical phenomena observed in this system. First, a description is made of the temperature and flow fields, as well as the species concentration distribution in the torch nozzle using both possibilities of He or Ar as the plasma gas. This is followed in the second part of the thesis by a model aimed to study the nucleation and evolution of the metal particles acting as catalyst for CNT growth in the nozzle. In the third part, the modeling of the TCE pyrolysis process in the flow was carried out. The fluid dynamics equations are used in this system showing supersonic characteristics. A realizable k-? model is used to address the turbulent effects in the flow fields. The moment method is employed to calculate the formation of the fine catalyst particles from the metal vapor injected. Within the supersonic domain of the flow field, the influence of existing shock waves on the particle nucleation is discussed, as well as the chemical reactions involved. Results show that the supersonic phenomena make it possible for metal particles to nucleate and be maintained in small sizes. This however also causes a backflow in the nozzle, which partially contributes to the experimentally observed soot deposition and CNT growth within the nozzle. The carbon containing gas experiences a fast dissociation process once it enters the nozzle. The produced carbon species are maintained in small clusters of carbon atoms in the high temperature environment within the nozzle. These clusters and atoms serve as the source of CNT growth and form a layer of carbon deposit on the surface of the nozzle. This deposited layer acts as a thermal insulator changing the conditions in the nozzle, particularly on the wall. A modeling of this effect is performed, confirming that the basic requirements for CNT growth are attained within the nozzle itself. A parametric study of the process is carried out and suggestions are made on the geometry of the reactor and the operating parameters for the formation of CNT. These modeling results suggest that the process can be optimized with carefully chosen operating parameters. With the specific design of the nozzle used here, it is recommended to operate at lower pressures in the reactor in order to avoid a backflow in the nozzle. Different kinds of metal catalyst can be used in this system and the reactor length should be adjusted accordingly in order to optimize the outcome of the process.

Guo, Liping

324

Experimental investigations on a permanent magnet brushless DC motor fed by PV array for water pumping system  

SciTech Connect

This paper describes the experimental study carried out on a Permanent Magnet Brushless DC (PMBLDC) Motor drive coupled to a pump load powered by photovoltaic (PV) array for water pumping system. A simple low cost prototype controller has been designed and developed without current and position sensors which reduces drastically the overall cost of the drive system. This controller is used to test the dynamic behavior of the PMBLDC motor drive system. The mathematical model of the system is developed with a view to carrying out a comparison between experimental and simulated response of the drive system. The necessary computer algorithm is developed to analyze the performance under different conditions of varying solar insolation for a pump load. The developed state space equations are simulated to obtain the performance characteristics which are also verified by conducting suitable experiments on the development system.

Putta Swamy, C.L.; Singh, B.; Singh, B.P.; Murthy, S.S. [IIT Delhi, New Delhi (India). Dept. of Electrical Engineering

1996-12-31

325

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

326

Resistance in a Wire  

NSDL National Science Digital Library

Learn about the physics of resistance in a wire. Change its resistivity, length, and area to see how they affect the wire's resistance. The sizes of the symbols in the equation change along with the diagram of a wire.

Simulations, Phet I.; Dubson, Michael; Adams, Wendy; Gratny, Mindy

2004-06-01

327

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

328

These cables have been ordered by DESY: System Cable # of wires # of cables length (m) delivery Connectors # of connectors delivery Preparation of cable  

E-print Network

These cables have been ordered by DESY: System Cable # of wires # of cables length (m) delivery Connectors # of connectors delivery Preparation of cable high pt high voltage 1 145 à 40 m 6000 6000 SHV 26000 SHV-connectors 1200 1200 pbe electronic CAB04.XLS(Cables) Page 1 printed :08.07.1998 #12;high

329

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

PubMed

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 microm in the five X pinches. Typical images have a 16x8 mm2 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 microm 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 microm spatial resolution. PMID:18377006

Douglass, J D; Hammer, D A

2008-03-01

330

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

NASA Astrophysics Data System (ADS)

A new imaging system for 1MA 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 10.2to30?m in the five X pinches. Typical images have a 16×8mm2 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 3-5keV. 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 0.015to1.1?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?m spatial resolution.

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

2008-03-01

331

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

SciTech Connect

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.

Douglass, J. D.; Hammer, D. A. [Laboratory of Plasma Studies, Cornell University, 439 Rhodes Hall, Ithaca, New York 14853 (United States)

2008-03-15

332

Vibration Monitoring of the Voigt Bridge using Wired and Wireless Monitoring Systems  

Microsoft Academic Search

Structural monitoring systems using wireless sensors have the potential to serve as low-cost alternatives to commercially available cable-based monitoring systems. This paper describes a wireless sensing prototype system specifically designed for structural monitoring applications. To validate the performance of the prototype system, a network of up to 20 wireless sensing units is installed on the Voigt Bridge located on the

Yang Wang; Kenneth J. Loh; Jerome P. Lynch; Michael Fraser; Kincho Law; Ahmed Elgamal

2006-01-01

333

the 4th Power Electronics, Drive Systems & Technologies Conference, PEDSTC 2013 Simultaneous Sensing cum Actuating DC Motor  

E-print Network

drives, advanced permanent magnet servos, and piezoelectric haptic actuators have created a new paradigm Sensing cum Actuating DC Motor Ali Daraeepour Duke University Durham, North Carolina, USA a of a DC motor platform without using conventional sensors. A back-drivable DC motor platform is developed

Boyer, Edmond

334

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

PubMed

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

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

335

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

PubMed

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

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

336

Application of a one-wire digital temperature sensor in the monitoring system of a granary's temperature  

NASA Astrophysics Data System (ADS)

A temperature monitoring system with characteristics of bus topology structure is made up of computer, interface adapter, bus driver, bus converter, transmission line and especially 1-wire digital temperature sensor DS18B20. Category 5 twisted-pair is used to form a tree-like or star-like network, in which more than 500 digital temperature sensors can be connected. Bus drivers and converters in network are composed of low-cost 74HC series logic ICs which has a very low static power consumption and high performance, so they can be powered through the sensor bus and make installation, maintenance, and expansion of system very convenient. Because of hardware fault-tolerant technology used by bus driver and converter circuits, the fault sensor branch or branch bus can automatically detach from the main bus and will not affect normal working of other sensors in network, so to solve the problem of a certain sensor or branch's damage causing the paralysis of entire bus. The length of sensor bus can extend to more than 1000 meters. It is very suitable for the multi-point temperature monitoring sites where the detected points are relative concentrated such as food storage, vegetables greenhouses and so on.

Ma, Hongtao; Wang, Xiaojun; Zhang, Xiuqing

2009-07-01

337

Wire insulation defect detector  

NASA Technical Reports Server (NTRS)

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.

Greulich, Owen R. (Inventor)

2004-01-01

338

Cipher Printing Telegraph Systems For Secret Wire and Radio Telegraphic Communications  

Microsoft Academic Search

This paper describes a printing telegraph cipher system devetoped during the World War for the use of the Signal Corps, U. S. Army. This system is so designed that the messages are in secret form from the time they leave the sender until they are deciphered automatically at the office of the addressee. If copied while en route, the messages

G. S. Vernam

1926-01-01

339

A Novel N-Input Voting Algorithm for X-by-Wire Fault-Tolerant Systems  

PubMed Central

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

Karimi, Abbas; Zarafshan, Faraneh; Al-Haddad, S. A. R.; Ramli, Abdul Rahman

2014-01-01

340

Underwater electrical wire explosion  

Microsoft Academic Search

A brief review of the results obtained in recent research of underwater electrical wire explosions using microsecond and nanosecond generators is presented. It was shown that the increase in the rate of energy input into the exploding wire allows one to increase the wire temperature and amplitude of shock waves (SWs). Estimated energy deposition into Cu and Al wire material

Ya E. Krasik; A. Fedotov; D. Sheftman; S. Efimov; A. Sayapin; V. Tz Gurovich; D. Veksler; G. Bazalitski; S. Gleizer; A. Grinenko; V. I. Oreshkin

2010-01-01

341

Windows: Life after Wire.  

ERIC Educational Resources Information Center

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.…

Razwick, Jerry

2003-01-01

342

Mitigation method of 3rd-harmonic voltage for a three-phase four-wire distribution system based on a series active filter for the neutral conductor  

Microsoft Academic Search

This paper proposes a series active filter for mitigation of the 3rd-harmonic voltage in a three-phase four-wire power distribution system in a building. The active filter which consists of a single-phase inverter can suppress the harmonic voltage of the system. The active filter is characterized by acting not only as a capacitor but also as a resistor for the 3rd-harmonic

Keiji Wada; Toshihisa Shimizu

2002-01-01

343

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

Microsoft Academic Search

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

J. D. Douglass; D. A. Hammer

2008-01-01

344

Genomewide identification of proteins secreted by the Hrp type III protein secretion system of Pseudomonas syringae pv. tomato DC3000  

PubMed Central

The ability of Pseudomonas syringae pv. tomato DC3000 to be pathogenic on plants depends on the Hrp (hypersensitive response and pathogenicity) type III protein secretion system and the effector proteins it translocates into plant cells. Through iterative application of experimental and computational techniques, the DC3000 effector inventory has been substantially enlarged. Five homologs of known avirulence (Avr) proteins and five effector candidates, encoded by genes with putative Hrp promoters and signatures of horizontal acquisition, were demonstrated to be secreted in culture and/or translocated into Arabidopsis in a Hrp-dependent manner. These 10 Hrp-dependent outer proteins (Hops) were designated HopPtoC (AvrPpiC2 homolog), HopPtoD1 and HopPtoD2 (AvrPphD homologs), HopPtoK (AvrRps4 homolog), HopPtoJ (AvrXv3 homolog), HopPtoE, HopPtoG, HopPtoH, HopPtoI, and HopPtoS1 (an ADP-ribosyltransferase homolog). Analysis of the enlarged collection of proteins traveling the Hrp pathway in P. syringae revealed an export-associated pattern of equivalent solvent-exposed amino acids in the N-terminal five positions, a lack of Asp or Glu residues in the first 12 positions, and amphipathicity in the first 50 positions. These characteristics were used to search the unfinished DC3000 genome, yielding 32 additional candidate effector genes that predicted proteins with Hrp export signals and that also possessed signatures of horizontal acquisition. Among these were genes encoding additional ADP-ribosyltransferases, a homolog of SrfC (a candidate effector in Salmonella enterica), a catalase, and a glucokinase. One ADP-ribosyltransferase and the SrfC homolog were tested and shown to be secreted in a Hrp-dependent manner. These proteins, designated HopPtoS2 and HopPtoL, respectively, bring the DC3000 Hrp-secreted protein inventory to 22. PMID:12032338

Petnicki-Ocwieja, Tanja; Schneider, David J.; Tam, Vincent C.; Chancey, Scott T.; Shan, Libo; Jamir, Yashitola; Schechter, Lisa M.; Janes, Misty D.; Buell, C. Robin; Tang, Xiaoyan; Collmer, Alan; Alfano, James R.

2002-01-01

345

A loss measurement system in a test facility for high-current superconducting cables and wires  

Microsoft Academic Search

The AC loss measurement system in the Twente test facility is operational. Preliminary results of the first loss measurements on a vacuum-welded conductor are presented. The Twente test facility is a high-current system in which superconductors can be tested up to 7 T and 25 kA. The loss measurements were done on a monolith conductor designed for TORE SUPRA, manufactured

A. J. M. Roovers; W. Uijttewaal; H. H. J. Ten Kate; B. Ten Haken; L. J. M. van de Klundert

1988-01-01

346

A peculiarity of silver-based corona wire heating on ozone generation  

Microsoft Academic Search

The effect of corona wire temperature on the ozone generation in the positive dc corona electrostatic precipitator is studied experimentally. The external heating of the corona wire can suppress the ozone generation. In this study, nichrome and two kinds of silver-based wires 0.1 mm diameter were tested as discharges electrodes. The nichrome corona wire heating shows a well-known monotonic decreasing

Rafael Sh. Islamov; Yuriy A. Krishtafovich

2011-01-01

347

Dilution control in single-wire stainless steel submerged arc cladding  

Microsoft Academic Search

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

Kotecki

1996-01-01

348

Adjustable Bracket For Entry Of Welding Wire  

NASA Technical Reports Server (NTRS)

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.

Gilbert, Jeffrey L.; Gutow, David A.

1993-01-01

349

Behavior of exploding wires  

Microsoft Academic Search

Summary form only given. Exploding wire is performed by rapidly heating the wire to vaporization temperature with a high current pulse flowing through the wire. Exploding wires have found many applications among which are the opening switches named fuses in the circuits for inductive energy storage, the discharge loads of X-pinch or Z-pinches, namely wire array Z-pinches, and the production

Z. G. Mao; X. B. Zou; X. X. Wang; W. H. Jiang

2009-01-01

350

Stretched Wire Mechanics  

SciTech Connect

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.

Bowden, Gordon; /SLAC

2005-09-06

351

SpaceWire Architectures: Present and Future  

NASA Technical Reports Server (NTRS)

A viewgraph presentation on current and future spacewire architectures is shown. The topics include: 1) Current Spacewire Architectures: Swift Data Flow; 2) Current SpaceWire Architectures : LRO Data Flow; 3) Current Spacewire Architectures: JWST Data Flow; 4) Current SpaceWire Architectures; 5) Traditional Systems; 6) Future Systems; 7) Advantages; and 8) System Engineer Toolkit.

Rakow, Glen Parker

2006-01-01

352

Auxiliary resonant DC tank converter  

DOEpatents

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.

Peng, Fang Z. (Knoxville, TN)

2000-01-01

353

HTS Wire Development Workshop: Proceedings  

NASA Astrophysics Data System (ADS)

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: (1) Wire characterization: issues and needs; (2) technology for overcoming barriers: weak links and flux pinning; (3) manufacturing issues for long wire lengths; and (4) 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.

1994-07-01

354

HTS Wire Development Workshop: Proceedings  

SciTech Connect

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.

Not Available

1994-07-01

355

A compact DC-to-DC power converter for distributed power processing  

SciTech Connect

This paper presents a compact (55 W/in[sup 3]), efficient (86% power train), 1 MHz switch-mode, dc-to-dc power converter contained in a 2 in by 2 in by 0.25 in, 1 in[sup 3] package. It also describes the interleaved forward topology, steady-state analysis, switch transitions, capacitor substrate, planar printed-wiring-board transformer, packaging, electrical performance, power loss analysis, thermal analysis, reliability, and efficiency and power density improvements.

Lo, D.S.; Mulkern, J.H.; Henze, C.P. (Paramax Systems Corp., A Unisys Co., St. Paul, MN (United States))

1992-10-01

356

Wired for behaviors: from development to function of innate limbic system circuitry  

PubMed Central

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

Sokolowski, Katie; Corbin, Joshua G.

2012-01-01

357

Ionic wind generation by a wire-cylinder-plate corona discharge in air at atmospheric pressure  

SciTech Connect

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.

Colas, Dorian F.; Ferret, Antoine; Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O. [Laboratoire EM2C, UPR 288, CNRS, Ecole Centrale Paris, Grande Voie des Vignes, 92290 Chatenay-Malabry (France)

2010-11-15

358

Plated wire memory subsystem  

NASA Technical Reports Server (NTRS)

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.

Carpenter, K. H.

1974-01-01

359

Wireless wire-the 60 GHz ultra-low power radio system  

Microsoft Academic Search

This article presents basic issues regarding design and development of a 60 GHz ultra-low power radio system for ambient intelligence (AmI) applications. It demonstrates the validity of choosing the 60 GHz frequency band to design low power radios by a mathematical model, and proposes an overview of a cross-layer optimization flow to minimize power dissipation. Moreover, a completed RF front-end

Xia Li; Peter Baltus; Dusan Milosevic; Wei Deng; Paul van Zeijl; Neil Bird; Arthur van Roermund

2009-01-01

360

Influence of Friction Resistance on Expression of Superelastic Properties of Initial NiTi Wires in "Reduced Friction" and Conventional Bracket Systems.  

PubMed

Objectives. The aim of this study was to assess the influence of resistance to sliding on expression of superelastic properties of NiTi wires. Methods and Materials. A three-point bending test was performed for 0.014 NiTi wire engaged in self-ligating (Damon, SmartClip, In-Ovation) and conventional brackets (Victory) ligated with regular and reduced friction modules (Slide). The wire was deflected in the buccal direction and allowed to straighten. The maximum load, unloading plateau and unloading capacity were registered. Results. The lowest activation load was required in the active self-ligating group (In-Ovation 2.2 ± 0.4?N) and reduced friction module group (Victory/Slide 2.9 ± 0.4?N), followed by the passive self-ligating systems (Damon 3.6 ± 0.7?N, SmartClip 3.7 ± 0.4?N). Higher activation load was obtained in the conventionally ligated group (Victory/module 4.5 ± 0.4?N). Unloading plateau phase with the load magnitude ranging from 1.27 ± 0.4?N (In-Ovation) to 1.627 ± 0.4?N (Slide) was distinct in all groups but one (Victory). Conclusions. Higher friction at flanking points reduces the net force delivered by the wire. Unloading plateau phase of NiTi load-deflection curve disappears in the conventionally ligated group thus indicating to an incomplete expression of NiTi superelastic properties. A rigid passive bracket clip amplifies resistance to sliding in an active configuration and produces a permanent deflection of the wire. PMID:20981153

Reznikov, Natalie; Har-Zion, Gilad; Barkana, Idit; Abed, Yosef; Redlich, Meir

2010-01-01

361

DC arc weld starter  

DOEpatents

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.

Campiotti, Richard H. (Tracy, CA); Hopwood, James E. (Oakley, CA)

1990-01-01

362

Systems biology in psychiatric research: from complex data sets over wiring diagrams to computer simulations.  

PubMed

The classification of psychiatric disorders has always been a problem in clinical settings. The present debate about the major systems in clinical practice, DSM-IV and ICD-10, has resulted in attempts to improve and replace those schemes by some that include more endophenotypic and molecular features. However, these disorders not only require more precise diagnostic tools, but also have to be viewed more extensively in their dynamic behaviors, which require more precise data sets related to their origins and developments. This enormous challenge in brain research has to be approached on different levels of the biological system by new methods, including improvements in electroencephalography, brain imaging, and molecular biology. All these methods entail accumulations of large data sets that become more and more difficult to interpret. In particular, on the molecular level, there is an apparent need to use highly sophisticated computer programs to tackle these problems. Evidently, only interdisciplinary work among mathematicians, physicists, biologists, and clinicians can further improve our understanding of complex diseases of the brain. PMID:22231839

Tretter, Felix; Gebicke-Haerter, Peter J

2012-01-01

363

A flyback-type single phase utility interactive inverter with low-frequency ripple current reduction on the DC input for an AC photovoltaic module system  

Microsoft Academic Search

In recent years, interest in natural energy has grown because of increased environmental concerns. Many kinds of inverter circuits and their control schemes for photovoltaic (PV) power generation systems have been studied. In a conventional system, the PV array in which many PV modules are connected in series is used to obtain sufficient DC-bus voltage for generating an AC utility

Toshihisa Shimizu; Keiji Wada; Naoki Nakamura

2002-01-01

364

Design and characterization of the DC acceleration and transport system required for the IMW Free Electron Master experiment  

SciTech Connect

A Free Electron Maser (FEM) has been constructed and is soon to be tested at the FOM Institute (Rijnhuizen) Netherlands with the ultimate goal of producing 1 MW long pulse to CW microwave output in the range 130 GHz to 250 GHz. The DC acceleration and beam transport systems is eventually to be used in a depressed collector configuration requiring 99.8% beam transmission in order that the High Voltage 2MV supply be required only to supply 20 milliamps of body current. A relativistic version of the Herrmann optical theory originally developed for microwave tube beams is used to take in account thermal electrons far out on the gaussian distribution tail which can translate into beam current well outside the ideal beam edge. This theory is applied to the FOM beamline design and predicts that the beam envelope containing 99.8% of the current can be successfully transported to the undulator for a wide range of assume d emittance values.

Caplan, M. [Lawrence Livermore National Lab., CA (United States); Van Der Geer, C.; Valentini, M.; Urbanus, W. [FOM-Instituut voor Plasmafysica, Rijnhuizen (Netherlands)

1995-08-01

365

A novel approach to the design of a shunt active filter for an unbalanced three-phase four-wire system under nonsinusoidal conditions  

Microsoft Academic Search

A new approach is presented for the design of a shunt active filter in a three-phase, four-wire distribution system with unbalanced, distorted sources and unbalanced loads. The purpose of the shunt active filter is to provide compensation currents such that the source needs to supply balanced (positive-sequence) fundamental source current at unity power factor even though the load consumes harmonic

Cheng-Che Chen; Yuan-Yih Hsu

2000-01-01

366

A Non-Linear Control Strategy for Instantaneous Power Factor Correction in 3-ø 4Wire Electrical Systems under Asymmetrical and Non-Linear Loads  

Microsoft Academic Search

A non-linear control strategy in a rotating frame for an active filter based on a voltage source converter shunt topology in a three-phase four-wire electrical system is proposed. The converter in combination with the proposed control strategy guarantees balanced overall currents, unity displacement power factor, and reduced current harmonics in the common coupling point. These features are achieved regardless of

J. R. Sommer; J. R. Espinoza; L. A. Moran

2006-01-01

367

A novel control strategy for active filters usable in harmonic polluted and\\/or imbalanced utility voltage case of 3-phase 4-wire distribution systems  

Microsoft Academic Search

This paper presents a new control strategy for parallel active filters. The instantaneous positive sequence extraction of load current and utility voltage is combined with the p-q theory. This method is able to control a four leg active filter for compensation of reactive power, current harmonics, three-phase imbalance and neutral current cancellation simultaneously in 3-phase 4-wire distribution systems. The presented

M. Tarafdar Haque; T. Ise; S. H. Hosseini

2000-01-01

368

PLL-Less Active Power Filter Based on One-Cycle Control for Compensating Unbalanced Loads in Three-Phase Four-Wire System  

Microsoft Academic Search

In this paper, a shunt active power filter (APF) based on unified constant frequency integration or one-cycle control (Smedley et al., 2001) for compensating unbalanced loads in a three-phase four-wire system is explored. The APF provides compensation currents in such a way that the utility supplies only the balanced fundamental current at unity power factor, even if the load draws

Sachine Hirve; Kishore Chatterjee; B. G. Fernandes; M. Imayavaramban; Suman Dwari

2007-01-01

369

Singleloop voltage and frequency control of stand-alone three-phase four-wire renewable energy conversion system with battery storage  

Microsoft Academic Search

In this paper, single control loop based scheme for regulation of voltage and frequency of Self Excited Induction Generator (SEIG) based stand-alone 3-phase 4-wire renewable energy conversion system under source and balanced\\/unbalanced load perturbations is presented. The regulation is accomplished by maintaining reactive and active power balance across individual phases of SEIG using a Generalized Impedance Controller (GIC). GIC is

J. K. Chatterjee; Priyesh J. Chauhan

2011-01-01

370

Bi-Directional DC-DC Converter for PHEV Applications  

SciTech Connect

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.

Abas Goodarzi

2011-01-31

371

Wire Test Grip Fixture  

NASA Technical Reports Server (NTRS)

Wire-testing issues, such as the gripping strains imposed on the wire, play a critical role in obtaining clean data. In a standard test frame fitted with flat wedge grips, the gripping action alone creates stresses on the wire specimen that cause the wire to fail at the grip location. A new test frame, which is outfitted with a vacuum chamber, negated the use of any conventional commercially available wire test fixtures, as only 7 in. (17.8 cm) existed between the grip faces. An innovative grip fixture was designed to test thin gauge wire for a variety of applications in an existing Instron test frame outfitted with a vacuum chamber.

Burke, Christopher S.

2011-01-01

372

A Wire Position Monitor System for the 1.3 FHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator  

SciTech Connect

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.

Eddy, N.; Fellenz, B.; Prieto, P.; Semenov, A.; Voy, D.C.; Wendt, M.; /Fermilab

2011-08-17

373

Chemistry of radiation damage to wire chambers  

SciTech Connect

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.

Wise, J.

1992-08-01

374

Optimizing wire parameters in exploding wire arrays  

Microsoft Academic Search

Exploding wire arrays as fast switches are of interest for explosive pulsed power applications utilizing magnetic flux compression. This type of opening switch has proven effective in producing pulses of several hundred kilovolts into vacuum diode loads. The research presented here discusses an exploding wire array capable of producing single digit kilo- joules, 100 nanosecond pulses when driven by a

C. Davis; A. Neuber; J. Stephens; A. Young; J. Dickens; M. Kristiansen

2010-01-01

375

Wire harness twisting aid  

NASA Technical Reports Server (NTRS)

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.

Casey, E. J.; Commadore, C. C.; Ingles, M. E.

1980-01-01

376

EMF wire code research  

SciTech Connect

This paper examines the results of previous wire code research to determines the relationship with childhood cancer, wire codes and electromagnetic fields. The paper suggests that, in the original Savitz study, biases toward producing a false positive association between high wire codes and childhood cancer were created by the selection procedure.

Jones, T.

1993-11-01

377

Wire-Identification Instrument  

NASA Technical Reports Server (NTRS)

Instrument automatically tests each wire in multiwire cable and identifies specified wire to be segregated or labeled and locates wire connected to specified connector pin. Instrument made with readily available CMOS integrated circuits. More efficient and reliable than conventional continuity testers and less expensive than computer controlled units.

Lonborg, J. O.

1985-01-01

378

49 CFR 236.73 - Open-wire transmission line; clearance to other circuits.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Open-wire transmission line; clearance to other circuits...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.73 Open-wire transmission line; clearance to other...

2012-10-01

379

49 CFR 236.73 - Open-wire transmission line; clearance to other circuits.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Open-wire transmission line; clearance to other circuits...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.73 Open-wire transmission line; clearance to other...

2013-10-01

380

49 CFR 236.73 - Open-wire transmission line; clearance to other circuits.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Open-wire transmission line; clearance to other circuits...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.73 Open-wire transmission line; clearance to other...

2011-10-01

381

49 CFR 236.73 - Open-wire transmission line; clearance to other circuits.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Open-wire transmission line; clearance to other circuits...APPLIANCES Rules and Instructions: All Systems Wires and Cables § 236.73 Open-wire transmission line; clearance to other...

2010-10-01

382

Modeling and simulation requirements for the analysis and design of DC distributed power electronic systems  

Microsoft Academic Search

The objective of this paper is to establish which are the requirements of the component models in a distributed power system in order to satisfy the necessities of the system architect. Based on the information that will help the designer to make the right decision for its architecture and the selection of their components, different levels of modeling will be

J. A. Oliver; R. Prieto; L. Laguna; J. A. Cobos

2008-01-01

383

Model-based condition monitoring of an actuator system driven by a brushless DC motor  

Microsoft Academic Search

Air pressure in passenger aircrafts is controlled by opening and closing an outflow valve, which serves to release air from the cabin. Early identification of potential malfunctions in the underlying actuator-driven system is important both from the point of view of cost-efficient maintenance as well as overall safety. This paper presents a system for diagnosing faults in a valve actuator

?ani Juri?i?; Olaf Moseler; Andrej Rakar

2001-01-01

384

Leadership Changes Reinvigorate Cleveland's Health Care Market. Washington, DC: Center for Studying Health System Change  

Microsoft Academic Search

New leaders at Cleveland’s two major hospital systems—the Cleveland Clinic Health System (CCHS) and University Hospitals Health System (UHHS)—have helped strengthen the organizations’ financial positions and soothe long-standing rivalries, according to a new report from the Community Tracking Study.

Sally Trude; Gloria J. Bazzoli; Jon B. Christianson; Anneliese M. Garland; rea Staiti; Erin Fries Taylor

2005-01-01

385

DC current injection into the network from PV inverters of <5 kW for low-voltage small grid-connected PV systems  

Microsoft Academic Search

The present paper is focused on the study of DC current injection for low-voltage small grid-connected PV systems, which is one of the power quality requirements of utility companies. To achieve this aim, the existing status of guidelines and regulations in six selected countries where the development in the grid PV sector has evolved rapidly over the last decade (Australia,

V. Salas; M. Alonso-Abella; E. Olías; F. Chenlo; A. Barrado

2007-01-01

386

Design, analysis and limitations of a DC-to-AC converter usable for interface alternative energy sources and energy storage systems with the utility grid  

Microsoft Academic Search

A DC-AC power converter design that can be used to interface any type of alternative energy source or energy storage system with the utility grid is presented. The converter is capable of real and reactive power exchanges between the utility grid and the alternative energy source(s). The control philosophy is very simple and allows for the synthesis of useful harmonics.

Ashim K. Chakravorti; Alexander E. Emanuel

1993-01-01

387

30 CFR 77.705 - Guy wires; grounding.  

...Grounding § 77.705 Guy wires; grounding. Guy wires from poles supporting high-voltage transmission lines shall be securely connected to the system ground or be provided with insulators installed near the pole...

2014-07-01

388

47 CFR 32.2321 - Customer premises wiring.  

Code of Federal Regulations, 2010 CFR

...COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions...232, Station Connections, inside wiring subclass. (b) Embedded Customer Premises Wiring is that investment in customer...

2010-10-01

389

DC-SQUID magnetometer system for detecting vector value of magnetic field  

SciTech Connect

A vector magnetometer system for biomagnetic applications is described. The vector magnetometer system consists of 2 vector magnetometers and each vector magnetometer consists of 3 integrated SQUID magnetometers located perpendicularly to each other to detect 3 orthogonal components of the magnetic field simultaneously. The resolution of the each orthogonal components of the magnetic field vector is 11 fT/..sqrt..Hz in the white noise region.

Nakanishi, M.; Kasai, N.; Kado, H.; Koyanagi, M.

1989-03-01

390

High-voltage (270 V) dc power-generating system for fighter aircraft  

NASA Astrophysics Data System (ADS)

The advantages of using high voltage, direct current advanced power generating systems in fighter aircraft are discussed. Weight reduction is achieved. Efficiency is increased 85 to 90 percent by eliminating the constant speed drive. Power interruptions are eliminated. There are no speed restrictions and no powerline constraints. Personal safety is increased by eliminating the hold on frequency, present in ac systems, which causes muscle contractions.

McGinley, K. M.

1983-06-01

391

High-voltage (270 V) dc power-generating system for fighter aircraft  

NASA Technical Reports Server (NTRS)

The advantages of using high voltage, direct current advanced power generating systems in fighter aircraft are discussed. Weight reduction is achieved. Efficiency is increased 85 to 90 percent by eliminating the constant speed drive. Power interruptions are eliminated. There are no speed restrictions and no powerline constraints. Personal safety is increased by eliminating the hold on frequency, present in ac systems, which causes muscle contractions.

Mcginley, K. M.

1983-01-01

392

The Use of Software Agents for Autonomous Control of a DC Space Power System  

NASA Technical Reports Server (NTRS)

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.

May, Ryan D.; Loparo, Kenneth A.

2014-01-01

393

Solar energy system performance evaluation: Forest City Dillon, Washington, D.C., January 1980 - December 1980  

Microsoft Academic Search

An active solar energy system consisting of single glazed flat plate collectors, 3200 gallons of storage liquid, and an auxiliary oil fired boiler, was designed to supply 59% of the hot water demand for a high rise apartment building. The annual solar fraction predicted by the f chart simulation was 37%, and the solar fraction measured was 32%. Other measures

D. W. Missal

1980-01-01

394

Low speed control of a DC motor driving a mechanical system with fuzzy adaptive compensation  

E-print Network

and lubricated sliding junctions. For experiments, an IBM PC, a DSPACE DSP board, SE uLM and Real Time Workshop are used. All three control systems can achieve such a very low sustainable speed as 0.005 rad/sec without stick-slip oscillations, which appear when...

Hyun, Dongyoon

2012-06-07

395

A System for Speed and Torque Control of DC Motors with Application to Small Snake Robots  

E-print Network

for Minimally Invasive Surgery (MIS) of the upper airways. The robot system will includes three robot arms Minimally invasive surgery (MIS) of the throat is charac- terized by insertion of endoscopes and multiple the angle of approach, the rotation about and the position along the axis of the DDU holder. The TMU

Simaan, Nabil

396

"Forback" Dc-To-Dc Converters  

NASA Technical Reports Server (NTRS)

Dc-to-dc power-converter circuits called "forback" resemble circuits of standard configurations called "forward", "flyback", and "Cuk". Circuit employs minor modifications to existing topologies, combines advantages, while eliminating disadvantages, of older circuits.

Lukemire, Alan T.

1992-01-01

397

Compensation in nonsinusoidal, unbalanced three-phase four-wire systems with active power-line conditioner  

Microsoft Academic Search

For three-phase four-wire circuits, two compensation criteria have been established: one based on the instantaneous value concept and the other on the average value concept. Thus, according to the instantaneous value concept the non instantaneous power current is reduced, without altering the instantaneous active power. According to the average value concept, the nonactive average-current is reduced, without altering the average

P. Salmeron; J. C. Montano; J. R. Vazquez; J. Prieto; A. Perez

2004-01-01

398

Reliability Assessment of Fault-Tolerant Dc-Dc Converters for Photovoltaic Applications  

E-print Network

Reliability Assessment of Fault-Tolerant Dc-Dc Converters for Photovoltaic Applications Sairaj V in photovoltaic energy processing applications is presented. The proposed approach acknowledges the influence through several case studies. Index Terms-- Markov reliability modeling, photovoltaic systems, power

Liberzon, Daniel

399

WIRE, SOFIA and SIRTF  

NASA Technical Reports Server (NTRS)

WIRE, SOFIA and SIRTF are three planned NASA missions for infrared astronomy. Each will make significant contributions to the study of exo-zodiacal dust, planetary debris disks, and/or the zodiacal material within our own solar system. These missions and their measurement and scientific capabilities are synopsized. The principal contribution of these missions to this field of study will be to establish and strengthen its intellectual foundations rather than to pinpoint specific targets for planetary searches. This is consistent with their relatively near-term availability. Moreover, this intellectual understanding can assure that subsequent missions approach this subject from a sound scientific perspective which will yield valuable results independent of the success of a particular planet finding strategy. Each of these missions - most urgently WIRE with its Fall, 1998 launch date - would make good use of a list of candidate target stars for exo-zodiacal/planet-finding studies. The preparation of such a list was one of the recommendations of the exo-zodiacal workshop.

Werner, Michael

1998-01-01

400

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)

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.

Wood, M. E.

1980-01-01

401

Underwater electrical wire explosion  

NASA Astrophysics Data System (ADS)

A brief review of the results obtained in recent research of underwater electrical wire explosions using microsecond and nanosecond generators is presented. It was shown that the increase in the rate of energy input into the exploding wire allows one to increase the wire temperature and amplitude of shock waves (SWs). Estimated energy deposition into Cu and Al wire material of up to 200 eV/atom was achieved. In microsecond time scale wire explosion, a good agreement was attained between the wire resistance calculated using the equation of state (EOS) and that obtained experimentally. Conversely, in nanosecond time scale wire explosion, the wire resistance of EOS was modified in order to fit experimental data. Analysis of the emitted radiation showed that black body approximation cannot be used to characterize exploding wire radiation. It was found that <=24% of the deposited energy is transferred into the water flow's mechanical energy. Also, it was shown that converging SWs formed by the explosion of cylindrical wire arrays can be used to achieve a pressure up to 250 kbar at the axis of implosion. Hydrodynamic simulations showed that with the use of relatively moderate pulsed power generators with stored energy of several hundred kilojoules, a pressure of several megabar can be achieved at the axis of implosion.

Krasik, Ya E.; Fedotov, A.; Sheftman, D.; Efimov, S.; Sayapin, A.; Gurovich, V. Tz; Veksler, D.; Bazalitski, G.; Gleizer, S.; Grinenko, A.; Oreshkin, V. I.

2010-06-01

402

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

Code of Federal Regulations, 2012 CFR

...Trolley wires, trolley feeder wires, and bare signal wires shall be insulated adequately where they pass through...doors and stoppings, and where they cross other power wires and cables. Trolley wires and trolley feeder wires shall be guarded...

2012-07-01

403

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

Code of Federal Regulations, 2013 CFR

...Trolley wires, trolley feeder wires, and bare signal wires shall be insulated adequately where they pass through...doors and stoppings, and where they cross other power wires and cables. Trolley wires and trolley feeder wires shall be guarded...

2013-07-01

404

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

Code of Federal Regulations, 2010 CFR

...Trolley wires, trolley feeder wires, and bare signal wires shall be insulated adequately where they pass through...doors and stoppings, and where they cross other power wires and cables. Trolley wires and trolley feeder wires shall be guarded...

2010-07-01

405

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

Code of Federal Regulations, 2011 CFR

...Trolley wires, trolley feeder wires, and bare signal wires shall be insulated adequately where they pass through...doors and stoppings, and where they cross other power wires and cables. Trolley wires and trolley feeder wires shall be guarded...

2011-07-01

406

Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade  

NASA Astrophysics Data System (ADS)

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.

Feld, L.; Fimmers, C.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Rittich, D.; Sammet, J.; Wlochal, M.

2014-01-01

407

NASA wiring for space applications program test results  

NASA Technical Reports Server (NTRS)

The electrical power wiring tests results from the NASA Wiring for Space Applications program are presented. The goal of the program was to develop a base for the building of a lightweight, arc track-resistant electrical wiring system for aerospace applications. This new wiring system would be applied to such structures as pressurized modules, trans-atmospheric vehicles, LEO/GEO environments, and lunar and Martian environments. Technological developments from this program include the fabrication of new insulating materials, the production of new wiring constructions, an improved system design, and an advanced circuit protection design.

Stavnes, Mark; Hammoud, Ahmad

1995-01-01

408

Survey of arc tracking on aerospace cables and wires  

Microsoft Academic Search

The paper gives a survey of the phenomenon `Arc Tracking of Wires' which has been observed for the first time in wiring systems of aircraft and which recently has occurred also in spacecraft. Aircraft organizations are aware of this phenomenon and have tried to provide solutions to cope with this new wire failure, i.e. modification of cable design and manufacture,

F. Dricot; H. J. Reher

1994-01-01

409

Thin wire pointing method  

NASA Technical Reports Server (NTRS)

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.

Green, G.; Mattauch, R. J. (inventors)

1983-01-01

410

Thin wire pointing method  

NASA Astrophysics Data System (ADS)

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.

Green, G.; Mattauch, R. J.

1983-03-01

411

Development of contact-wire\\/battery hybrid LRV  

Microsoft Academic Search

Contact-wire\\/onboard battery hybrid railway electric vehicles run on a hybrid power source that enables energy to be fed from contact wires and \\/or onboard batteries. We developed a contact-wire\\/battery hybrid LRV (Light Rail Vehicle) and had it manufactured. This paper concerns the hybrid source technology for the contact-wire\\/battery hybrid system, and on the running results with onboard rechargeable lithium ion

Masamichi OGASA; Yoshiaki TAGUCHI

2010-01-01

412

A New Method for Cable Monitor Wire Protection Based on Timesharing Amplitude  

Microsoft Academic Search

Reason was analyzed that cable monitor wire protection was easy to make incorrect operation and failure action led by the stray interference signals. Full-wave Fourier Algorithm was deduced which was realized by filtering decaying dc component using table lookup. And on this basis, protection principle of time-sharing amplitude ac cable monitor wire with terminal resistance was proposed and proved in

Kui Chen; Changqing Sun

2010-01-01

413

Zinc wired rebar  

SciTech Connect

A novel method for corrosion protection of rebar in concrete is reported wherein it is galvanically protected by attaching a zinc wire along its length. The self-corrosion and galvanic-corrosion loss of the zinc wire is dependent on the water/cement ratio, the size of the cathode, and the concrete cover thickness. The wire acts as a sacrificial anode when the rebar embedded in concrete is exposed to corrosive environments.

Zhang, X.G.; Hwang, J. [COMINCO Product Technology Centre, Mississauga, Ontario (Canada)

1997-02-01

414

Sintered wire annode  

DOEpatents

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.

Falce, Louis R. (Surprise, AZ); Ives, R. Lawrence (Saratoga, CA)

2007-12-25

415

Superconductivity for Electric Systems Annual Peer Review Washington, DC July 27-29, 2004. OAK RIDGE NATIONAL LABORATORY  

E-print Network

FY 2004 Funding: $ 0.9 million: DOE OETD, Matching Funds at AMSC ORNL-AMSC Strategic Research Objective: Assist AMSC's development of a low-cost, robust 2G wire based on RABiTS technology through R conferences · Major achievements in all areas ORNL R&D AMSC 2G Development Low-cost, high performance

416

Wire-inhomogeneity detector  

DOEpatents

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.

Gibson, G.H.; Smits, R.G.; Eberhard, P.H.

1982-08-31

417

Weld Wire Investigation Summary  

SciTech Connect

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).

Cunningham, M.A.

1999-03-22

418

Concealed wire tracing apparatus  

DOEpatents

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.

Kronberg, J.W.

1994-05-31

419

Wiring Damage Analyses for STS OV-103  

NASA Technical Reports Server (NTRS)

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.

Thomas, Walter, III

2006-01-01

420

Early expansion in exploding multiple wire arrays  

SciTech Connect

A simple model is developed for the initial stage (blow-off and the onset of pinching) of a multiple exploded wire array. With obvious modifications the model can also be applied to single wires or other self-pinched plasma columns. Each wire in the array is modeled as a plasma cylinder undergoing self-similar radial motion, and the whole array is coupled self-consistently to an external circuit. The plasma expands initially; the onset of self-pinch is shown to be coincident with the plasma conductivity reaching a value large enough for skin effect to occur. The model is run for a variety of system parameters, and the choice of machine and wire parameters to attain particular objectives (e.g., rapid current rise, limited wire expansion, etc.) is discussed.

Bloomberg, H.W.; Lampe, M.; Colombant, D.G.

1980-10-01

421

Power wire signatures in passive infrared sensors  

NASA Astrophysics Data System (ADS)

Power cables present a persistent threat to helicopter pilots and have been responsible for a number of crashes in recent years. Active sensors are currently being developed to detect obstacles such as exposed power wires. However, the ability of passive sensors, such as forward-looking infrared (FLIR) systems currently employed on many rotary-wing aircraft, to detect such wires remains unclear. This study details observations, assumptions, and models that support the conclusion that wires are essentially reflective in nature, thus their signatures on passive thermal sensors depend principally on their surroundings. Because of this irregular nature and inconsistent appearance, predicting the performance of FLIRs in detecting wires is difficult and the utility of FLIRs as wire warning sensors is open to question.

Shea, James J.

1994-04-01

422

Nano-storage wires.  

PubMed

We report the development of "nano-storage wires" (NSWs), which can store chemical species and release them at a desired moment via external electrical stimuli. Here, using the electrodeposition process through an anodized aluminum oxide template, we fabricated multisegmented nanowires composed of a polypyrrole segment containing adenosine triphosphate (ATP) molecules, a ferromagnetic nickel segment, and a conductive gold segment. Upon the application of a negative bias voltage, the NSWs released ATP molecules for the control of motor protein activities. Furthermore, NSWs can be printed onto various substrates including flexible or three-dimensional structured substrates by direct writing or magnetic manipulation strategies to build versatile chemical storage devices. Since our strategy provides a means to store and release chemical species in a controlled manner, it should open up various applications such as drug delivery systems and biochips for the controlled release of chemicals. PMID:23859333

Lee, Dong Jun; Kim, Eunji; Kim, Daesan; Park, Juhun; Hong, Seunghun

2013-08-27

423

Digital Control Technologies for Modular DC-DC Converters  

NASA Technical Reports Server (NTRS)

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.

Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

2002-01-01

424

1998 wire development workshop proceedings  

SciTech Connect

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.

NONE

1998-04-01

425

Use of Second Generation HTS Wire in Filter Inductor Coils  

Microsoft Academic Search

AMSC's process for manufacturing Second Generation (2G) YBCO High Temperature Superconductor wire provides the flexibility to engineer practical 2G conductors with various architectures. For applications with high frequency ac components, a stainless steel stabilizer is used to minimize eddy current losses. An example of such an application is the so-called Buck Inductor, a filter inductor carrying a DC current onto

Cornelis L. H. Thieme; John P. Voccio; Kevin J. Gagnon; John H. Claassen

2009-01-01

426

Simulation and design of A DC-DC synchronous converter by intelligent optimization techniques  

Microsoft Academic Search

This paper presents the application of three intelligent optimization techniques for optimal design and analysis of a dc-dc converter with synchronous rectification which is often used in battery charge\\/discharge circuits in dc uninterruptible power supply systems. Converter models for simulation are designed for the forward and backup modes of operation. The results are analyzed and compared with the expected ideal

K. S. Rama Rao; Choon-Keat Chew

2010-01-01

427

Wire Array Photovoltaics  

NASA Astrophysics Data System (ADS)

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.

Turner-Evans, Dan

428

A Laser Based Instrument for MWPC Wire Tension Measurement  

E-print Network

A fast and simple method for the measurement of the mechanical tension of wires of Multi Wires Proportional Chambers (MWPCs) is described. The system is based on commercial components and does not require any electrical connection to the wires or electric or magnetic field. It has been developed for the quality control of MWPCs of the Muon Detector of the LHCb experiment in construction at CERN. The system allows a measurement of the wire tension with a precision better than 0.5% within 3-4 seconds per wire

Baldini, W; Evangelisti, F; Germani, S; Landi, L; Savrié, M; Graziani, G; Lenti, M; Lenzi, M; Passaleva, G; Carboni, G; De Capua, S; Kachtchouk, A

2007-01-01

429

Modeling and Simulation of an Asynchronous Generator with AC\\/DC\\/AC Converter Fed RLC Series Circuit in an Isolated Power Generation System  

Microsoft Academic Search

This paper expounds a simulation model of a self-excited asynchronous generator (SEASG) feeding R L load in conjunction with an AC\\/DC\\/AC converter fed RLC series circuit connected at the point of common coupling (PCC). Simulation model of the proposed system have been developed by using Matlab\\/Simulink. The result shows that the effect of RLC series circuit when operated at variable

K. Subramanian; K. K. Ray

2010-01-01

430

A Robust Approach to Controller Design for DC-DC Quasi-Resonant Converters  

Microsoft Academic Search

DC-DC quasi-resonant converters (QRCs) have a highly nonlinear and time-varying behavior as well as other types of DC-DC resonant converters such as conventional and multi-resonant converters. Changing in operating conditions, mainly due to variation in load and line disturbance, leads to significant changes on system dynamics so that desired performance and even stability are lost. Taking into consideration the uprising

Hassan Bevrani; Toshifumi Ise; Yasunori Mitani; Kiichiro Tsuji

2004-01-01

431

Tracking with wire chambers at the SSC  

SciTech Connect

Limitations placed on wire chambers by radiation damage and rate requirements in the SSC environment are reviewed. Possible conceptual designs for wire chamber tacking systems that meet these requirements are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given. 13 refs., 11 fig., 1 tab.

Hanson, G.G.; Gundy, M.C.; Palounek, A.P.T.

1989-07-01

432

DC/DC Converter Stability Testing Study  

NASA Technical Reports Server (NTRS)

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.

Wang, Bright L.

2008-01-01

433

WIRE Mishap Investigation Board Report  

E-print Network

Volume 1 WIRE Mishap Investigation Board Report June 8, 1999 #12;2 Table of Contents WIRE MISHAP........................................................................... 10 � WIRE Mishap Electronics Analysis: Failure Mechanism Determination.................... 17 � Summary of the Mishap

Rhoads, James

434

Mathematical and physical modeling of systems for metal delivery in the continuous casting of steel and DC casting of aluminum  

Microsoft Academic Search

In the continuous casting of steel, various nozzles have been used (e.g., bifurcated nozzles with ports inclined at various angles to the horizontal) to deliver metal from the tundish into the caster. An even greater variety of devices is used in the case of semi-continuous (direct chill (DC) or electromagnetic (EM)) casting of aluminum, for example, nozzles delivering metal into

D Xu; W. K Jones Jr; J. W Evans; D. P Cook

1998-01-01

435

Quantitative study of macroscopic quantum tunneling in a dc SQUID: A system with two degrees of freedom  

E-print Network

measurements at T=4.2 K, we are able to make quantitative comparison to the theories from 8 mK to 4.2 K. The excellent agreement between the data and the MQT theory demonstrates that tunneling from the zero-voltage state of the dc SQUID is well described...

Li, Shaoxiong; Yu, Yang; Zhang, Y.; Qiu, W.; Han, Siyuan; Wang, Z.

2002-08-01

436

Development of an automated AC-DC transfer measurement system for voltage and current at low frequencies  

Microsoft Academic Search

National Physical Laboratory India (NPLI) is the premier research & development center and the National Metrology Institute, which provides traceability in measurements by calibration throughout the country. Low Frequency voltage and current are very important quantities in electrical metrology. The standards for LF voltage and current are established by assigning AC-DC transfer difference to Thermal Converters (TCs) worldwide. The range

A. K. Govil; S. Ahmad; B. Pal; P. C. Kothari

2008-01-01

437

Advancement of In-Flight Alumina Powder Spheroidization Process with Water Droplet Injection Using a Small Power DC-RF Hybrid Plasma Flow System  

NASA Astrophysics Data System (ADS)

The correlation between plasma thermofluid characteristics and alumina powder spheroidization processes with water droplet injection using a small power DC-RF hybrid plasma flow system was experimentally clarified. Micro-sized water droplets with a low water flow rate were injected into the tail of thermal plasma flow so as not to disturb the plasma flow directly. Injected water droplets were vaporized in the thermal plasma flow and were transported upstream in the plasma flow to the torch by the backflow. After dissociation of water, the production of hydrogen was detected by the optical emission spectroscopy in the downstream RF plasma flow. The emission area of the DC plasma jet expanded and elongated in the vicinity of the RF coils. Additionally, the emission area of RF plasma flow enlarged and was visible as red emission in the downstream RF plasma flow in the vicinity below the RF coils due to hydrogen production. Therefore, the plasma flow mixed with produced hydrogen increased the plasma enthalpy and the highest spheroidization rate of 97% was obtained at a water flow rate of 15 Sm l/min and an atomizing gas flow rate of 8 S l/min using a small power DC-RF hybrid plasma flow system.

Jang, Juyong; Takana, Hidemasa; Park, Sangkyu; Nishiyama, Hideya

2012-09-01

438

75 FR 36298 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...  

Federal Register 2010, 2011, 2012, 2013

...DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; Model DC-8-50...DC-8-32, DC-8-33, DC- 8-41, DC-8-42, and DC-8-43 airplanes; Model DC-8-50...8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 airplanes; Model...

2010-06-25

439

75 FR 61989 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...  

Federal Register 2010, 2011, 2012, 2013

...DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; Model DC-8-50...DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 airplanes; Model DC-8-50...8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 airplanes; Model...

2010-10-07

440

Reduction of Device Currents for One Motor Type Multi-Functional-Converter-System  

NASA Astrophysics Data System (ADS)

There is no doubt that Hybrid Electrical Vehicle can preserve the environment. These vehicles have several electrical power sources. The power flows among these sources are controlled generally using DC/DC converters. Therefore the DC/DC converter is the important device in HV. This paper shows the method how to reduce the inverter device current of the Multi-Functional Converter System (MFCS) in our laboratory. The MFCS consists of a motor, inverters and additional wires except of DC/DC converters. The MFCS can realize controlling the power among several AC or DC electrical power sources besides controlling motor torque. The characteristic of this MFCS in this paper is that the MFCS has two three-phase star connected coils in one motor. The proposed method is realized using the characteristic. This paper shows the validity of the proposed method using the experiment examinations.

Nakai, Hideo; Ohtani, Hiroki; Inaguma, Yukio; Sasaki, Syoichi

441

NASA requirements and applications environments for electrical power wiring  

NASA Technical Reports Server (NTRS)

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.

Stavnes, Mark W.; Hammoud, Ahmad N.

1992-01-01

442

49 CFR 236.71 - Signal wires on pole line and aerial cable.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Signal wires on pole line and aerial cable. 236.71 Section 236...Instructions: All Systems Wires and Cables § 236.71 Signal wires on pole line and aerial cable. Signal wire on pole line shall be...

2010-10-01

443

49 CFR 236.71 - Signal wires on pole line and aerial cable.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Signal wires on pole line and aerial cable. 236.71 Section 236...Instructions: All Systems Wires and Cables § 236.71 Signal wires on pole line and aerial cable. Signal wire on pole line shall be...

2013-10-01

444

49 CFR 236.71 - Signal wires on pole line and aerial cable.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Signal wires on pole line and aerial cable. 236.71 Section 236...Instructions: All Systems Wires and Cables § 236.71 Signal wires on pole line and aerial cable. Signal wire on pole line shall be...

2012-10-01

445

49 CFR 236.71 - Signal wires on pole line and aerial cable.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Signal wires on pole line and aerial cable. 236.71 Section 236...Instructions: All Systems Wires and Cables § 236.71 Signal wires on pole line and aerial cable. Signal wire on pole line shall be...

2011-10-01

446

Wire-bond inspection in IC assembly  

NASA Astrophysics Data System (ADS)

Wire-bonding in IC assembly process involves making a physical connection between the IC 'die' and the 'lead' by bonding wires between the two. Inspection of wire-bond quality is a' highly labor-intensive process and currently efforts are being made to automate it. This paper presents the results of a research conducted into developing a comprehensive automated wire- bond visual inspection system that is capable of performing final accept/reject inspection, providing on-line process feedback, and assisting in process validation. The proposed inspection system consists of the inspection of the bond on a bond pad, the bond on a lead and the inter-connecting wire between a bond pad and its corresponding lead. The algorithms are based on simple and easily extractable features that ensure achieving the desired accuracy and speed. A novel but simple illumination system is proposed to obtain the images of the inter- connecting wires. The proposed system is validated using several state-of-the-art IC samples. This work is sponsored by the Ministry of Science Technology and Environment, Malaysia and Intel Technology Pvt. Ltd., Malaysia.

Rajeswari, Mandava; Rodd, Mike G.

1996-02-01

447

Diverging dc conductivity due to a flat band in a disordered system of pseudospin-1 Dirac-Weyl fermions  

NASA Astrophysics Data System (ADS)

Several lattices, such as the dice or the Lieb lattice, possess Dirac cones and a flat band crossing the Dirac point, whose effective model is the pseudospin-1 Dirac-Weyl equation. We investigate the fate of the flat band in the presence of disorder by focusing on the density of states (DOS) and dc conductivity. While the central hub site does not reveal the presence of the flat band, the sublattice resolved DOS on the noncentral sites exhibits a narrow peak with height ˜1/g with g the dimensionless disorder variance. Although the group velocity is zero on the flat band, the dc conductivity diverges as ln(1/g) with decreasing disorder due to interband transitions around the band touching point between the propagating and the flat band. Generalizations to higher pseudospin are given.

Vigh, Máté; Oroszlány, László; Vajna, Szabolcs; San-Jose, Pablo; Dávid, Gyula; Cserti, József; Dóra, Balázs

2013-10-01

448

Commercialization of ceramic superconductor composite wires  

Microsoft Academic Search

Recent advances in the development of high-temperature superconductor (HTS) composite wires demonstrate an increasingly realistic potential for commercial applications, such as power transmission cables, motors, and superconducting magnetic energy storage (SMES) systems. Successful commercialization requires the development of manufacturing technologies that can produce high-performance, low-cost HTS wires. The achievement of this goal has been occurring through an understanding of the

G. N. Riley; W. L. Carter

1993-01-01

449

Orbiter Kapton wire operational requirements and experience  

NASA Technical Reports Server (NTRS)

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.

Peterson, R. V.

1994-01-01

450

Hot wire anemometer  

SciTech Connect

An electronic anemometer is described for measuring air mass flow in a conduit, comprising: a length of temperature-dependent resistive wire; a circuit board for holding at least a portion of the anemometer electronic circuitry; a rigid support member, the circuit board being attached to the member; and a pair of electrically conductive, resilient posts capable of withstanding the elevated operating temperatures encountered when the anemometer is operating, each of the posts having a wire-supporting end portion fixedly connected to the wire. The end portions are spaced apart and positionable in the conduit, and biased away from each other to hold the wire under tension, each of the posts further having a remote end portion fixedly held by the support member. The remote end portions are electrically connected to the electronic circuitry.

Watkins, D.W.

1986-08-12

451

Dilution control in single-wire stainless steel submerged arc cladding  

SciTech Connect

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.

Kotecki, D.J. [Lincoln Electric Co., Cleveland, OH (United States)

1996-02-01

452

High performance coupled-inductor DC-DC converters  

Microsoft Academic Search

Many emerging applications call for high-efficiency, high-step-up DC-DC converters. Basic DC-DC topologies encounter extreme duty ratio and severe rectifier reverse-recovery problems. Cascade DC-DC converters can meet the requirements with the drawbacks of extra complexity and higher cost. Coupled-inductor DC-DC converters can provide high step-up voltage gain without the penalty of extreme duty ratio, but the stress and the loss related

Qun Zhao; Fred C. Lee

2003-01-01

453

Cryogenic Pressure Seal for Wires  

NASA Technical Reports Server (NTRS)

High-pressure-seal formed by forcing polyurethane into space surrounding wire or cable in special fitting. Wire or cable routed through fitting then through a tightly fitting cap. Wire insulation left intact. Cap filled with sealant and forced onto the fitting: this pushes sealant into fitting so it seals wire or cable in fitting as well as in cap.

Ciana, J. J.

1984-01-01

454

High Efficient Low Noise Three Phase Voltage-Fed Soft-Switching Double PWM Converter System with A Single Resonant DC Link Snubber  

NASA Astrophysics Data System (ADS)

This paper presents a novel system prototype of auxiliary resonant DC link (ARDCL) assisted three phase double converter using IGBT power modules. In the ARDCL-based double converter, large current flows through the ARDCL circuit when the ARDCL circuit operates under heavier load current ranges. In addition to this, the gate pulse control timing sequences for switching power semiconductor devices used in the ARDCL circuit become more complicate actually. The active auxiliary resonant DC link snubber circuit has advantage point of small load currents which flow through the ARDCL circuit and does not actually require the complicated timing pulse control implementation for switching power semiconductor devices. In this paper, the system configuration double converter circuit and its operation principle are described for three phase voltage source type double soft-switching converter with a single ARDCL snubber. For a 10kVA prototype double converter system, conversion efficiency can be improved in addition to noise terminal voltage is reduced up to 20dBuV in maximum in the switching frequency range of 500kHz or more in comparison with the conventional three phase hard switching double converter system.

Sato, Shinji; Nagai, Shin-Ichiro; Yamamoto, Masayoshi; Rukonuzaaman, Md.; Nakaoka, Mutsuo

455

Splicing Wires Permanently With Explosives  

NASA Technical Reports Server (NTRS)

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.

Bement, Laurence J.; Kushnick, Anne C.

1990-01-01

456

Evolution of Upper Tropospheric Composition Perturbed by a Mesoscale Convective System during the Deep Convective Clouds and Chemistry (DC3) Campaign  

NASA Astrophysics Data System (ADS)

The role of deep convection in altering the chemical composition of the upper troposphere (UT) is well known, having been observed in many airborne campaigns, including dedicated studies that were part of the Deep Convective Clouds and Chemistry (DC3) experiment in May and June, 2012. The primary focus of DC3 was to characterize the details of transport from the boundary layer to the UT by isolated convective cells, and further to examine the evolution of air masses perturbed by the convection as chemical processing takes place the day after convective transport. These objectives were addressed by observations staged aboard the NSF/NCAR GV and NASA DC-8 aircraft platforms, which were deployed to study storms in Colorado, Oklahoma/West Texas, and northern Alabama, and to study aged outflow downwind of the storms. Because of the importance of Mesoscale Convective Systems (MCSs) in convective transport, their impact was assessed on two occasions as observations of opportunity during flights focused on other goals, and during one dedicated mission. The latter focused on a decaying nocturnal MCS that formed over the north central Great Plains and moved to the east over Illinois, Indiana, and Missouri during the day on June 21, 2012. The aircraft platforms were staged such that the DC-8 observed the aging from early morning to midday, and the GV observed from midday to early evening. The two aircraft overlapped on part of a flight leg to connect the measurements on the two platforms. This provided a 10.5 hour record of the atmospheric processing of the concentrations of a variety of gas-phase species as well as the composition and size distributions of aerosols in the outflow. By making use of air mass trajectories, the observations are placed on a photochemical age scale. This allows calculations of ozone production, production and growth of aerosols, net production of nitric acid, and budgets of HOx and its reservoirs in the MCS outflow. This provides quantitative information on the role of convection from MCSs in UT chemical composition and evolution. Flight tracks of DC-8 (magenta) and GV (yellow and red) during the MCS study on June 21, 2012. Visible and infrared satellite images near the end of the day are also shown. The numbers show the time (UTC) along the aircraft flight tracks.

Cantrell, C. A.; Barth, M. C.; Brune, W. H.; Rutledge, S. A.; Crawford, J. H.; Olson, J. R.; Flocke, F. M.

2013-12-01

457

Problems with aging wiring in Naval aircraft  

NASA Technical Reports Server (NTRS)

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.

Campbell, Frank J.

1994-01-01

458

A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications  

PubMed Central

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

Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

2012-01-01

459

A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.  

PubMed

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

Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

2012-01-01

460

Inhomogeneity of currents in a wire array during its exploding phase  

Microsoft Academic Search

The current in a wire array during its exploding phase has been studied. The wire array consisting of many thin wires is used as a plasma source in a z-pinch X-ray radiation system. The current distribution in the exploding wire array plays an important role in producing an initial symmetrical plasma. In the present experiment, four tungsten wires of 0.1

Yusuke Teramoto; Susumu Kohno; Naoyuki Shimomura; Sunao Katsuki; Hidenori Akiyama

2001-01-01

461

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...

462

Pin Wire Coating Trip Report  

SciTech Connect

A meeting to discuss the current pin wire coating problems was held at the Reynolds plant in Los Angeles on 2MAR04. The attendance list for Reynolds personnel is attached. there was an initial presentation which gave a brief history and the current status of pin wire coating at Reynolds. There was a presentation by Lori Primus on the requirements and issues for the coating. There was a presentation by Jim Smith of LANL on the chemistry and to some extent process development done to date. There was a long session covering what steps should be taken in the short term and, to a lesser extent, the long term. The coating currently being used is a blend of two polymers, polyethersulfone and polyparabanic acid (PPA) and some TiO2 filler. This system was accepted and put into production when the pin wire coating was outsourced to another company in 1974. When that company no longer was interested, the wire coating was brought in-house to Reynolds. At that time polyparabanic acid was actually a commercial product available from Exxon under the trade name Tradlon. However, it appears that the material used at Reynolds was synthesized locally. Also, it appears that a single large batch was synthesized in that time period and used up to 1997 when the supply ran out. The reason for the inclusion of TiO2 is not known although it does act as a rheological thickener. However, a more controlled thickening can be obtained with materials such as fumed silica. This material would have less likelihood of causing point imperfections in the coatings. Also, the mixing technique being used for all stages of the process is a relatively low shear ball mill process and the author recommends a high shear process such as a three roll paint mill, at least for the final mixing. Since solvent is added to the powder at Reynolds, it may be that they need to have the paint mill there.

Spellman, G P

2004-03-18

463

Dissipative Cryogenic Filters with Zero DC Resistance  

SciTech Connect

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.

Bluhm, Hendrik; Moler, Kathryn A.; /Stanford U., Appl. Phys. Dept

2008-04-22

464

Investigation of Carbon Wire X-pinch backlighting for Pulsed Power Driven Exploding Wire Experiments  

NASA Astrophysics Data System (ADS)

Exploding wire experiments have many important applications, including inertial confinement fusion research and laboratory astrophysical plasmas. Understanding of the dynamics of wire arrays is crucial to these applications. Details of wire ablation remain somewhat unclear, which lead to uncertainties in scaling to higher drive currents. The ablated coronal plasma is typically investigated using x-rays in the 3-5 keV range, however much of this plasma is highly transparent to this radiation, and information about the dynamics of coronal plasma above 10^19/cc is therefore lacking. A possible candidate for lower energy radiography is the carbon x-pinch, which produces x-rays below 1 keV. Experiments are conducted on GenASIS, a linear transformer driver, to study carbon x-pinches for wire array x-ray backlighting. This pulsed power system drives 250 kA into a short circuit and 200 kA into an x-pinch load. X-pinches formed from 20 ?m titanium and 10 ?m stainless steel wires are compared to the carbon system to provide more insight into the evolution and structure of exploding wires. Information from these comparisons will feed directly into the ongoing discussion of wire ablation at high currents.

McGraw, Sean; Bott, Simon; Beg, Farhat

2009-11-01

465

Test and Evaluation of the Magnograph (TM) unit, a nondestructive wire rope tester  

NASA Astrophysics Data System (ADS)

The nondestructive wire rope test device, a unitized AC/DC Magnograph, was tested for operational characteristics prior to acquisition by Naval field activities and start of inspection programs. The Magnograph was tested for loss of metallic area (LMA) and local fault (LF) detection accuracy. Wire ropes 1/2, 3/4, 1-1/8, 1-1/2, 2, and 2-1/2 inches in diameter were tested on a wire rope test track to find the accuracy of the unit. Two mining wire ropes, guy wires of a 1,000-ft-tall tower, and wire rope for 400-, 250-, and 30-ton cranes were used to determine operational characteristics of the Magnograph.

Underbakke, L. D.; Haynes, H. H.

1982-07-01

466

Wire-reinforced superalloys  

NASA Technical Reports Server (NTRS)

The problems and progress encountered in developing refractory-wire-reinforced superalloys for turbojet-engine applications at operating temperature within 1000-1200 C are reviewed. Particular attention is given to the problem of the compatibility of the fiber-reinforcement wire and the superalloy matrix and to the means of improving composite properties. Fiber development is described, since fibers with better properties would result in better composite properties. Matrix comp