Sample records for bridge flyback converter

  1. Active-clamping quad-flyback converter

    Microsoft Academic Search

    B.-R. Lin; H.-K. Chiang; F.-P. Tsao

    2009-01-01

    An active-clamping quad-flyback converter is proposed to achieve zero voltage switching (ZVS) for all power switches. The secondary sides of quad-flyback converter are connected in parallel to share the load current. Thus, the transformer copper losses and the conduction losses on the output diodes are reduced. Active-clamping part including one auxiliary switch and one clamp capacitor can release the energy

  2. An integrated flyback converter for DC uninterruptible power supply

    SciTech Connect

    Ma, K.W. [Ericsson Ltd., Quarry Bay (Hong Kong). Energy System Div.; Lee, Y.S. [Hong Kong Polytechnic Univ., Kowloon (Hong Kong). Dept. of Electronic Engineering

    1996-03-01

    An integrated flyback converter performing the combined functions of uninterruptible power supply (UPS) and switch-mode power supply (SMPS) is presented. This converter has a high voltage main power input and a low voltage backup battery input. DC output is obtained form the main input via a flyback converter during normal operation and from the backup battery via another flyback converter when input power fails. High conversion efficiency is achieved in normal, backup, and charging modes as there is only a single dc-dc conversion in each mode. The converter circuit is very simple, with two switching transistors, a relay for mode switching, and a single magnetic structure only. This new design offers substantial improvement in efficiency, size, and cost over the conventional cascade of UPS and SMPS due to single voltage conversion, high frequency switching, and removal of design redundancy. The operation, design, analysis, and experimental results of the converter are presented.

  3. Digital control of a Full-BridgeFlyback isolated current rectifier with power factor correction

    Microsoft Academic Search

    Janderson Duarte; Cassiano Rech; Marcello Mezaroba; Leandro Michels

    2009-01-01

    This paper presents the modeling and control of a single-stage isolated current rectifier with power factor correction based on full-bridge and flyback topologies. The state-space averaged model of the converter for step-down and step-up operation modes is presented, as well as the design and analysis of the digital control system. Experimental results based on a 3.5 kW prototype are presented

  4. Soft-switched PWM high-frequency with PFC converter using boost-flyback converter interleaved

    Microsoft Academic Search

    Carlos A. Gallo; J. A. Correa Pinto; L. C. de Freitas; V. J. Farias; E. A. A. Coelho

    2002-01-01

    This paper proposes as a power factor correction pre regulator converter an AC-DC interleaved boost-flyback using a nondissipative snubber and operating at 100 kHz per cell. That is composed by switches working in ZCS and ZVS way, controlled by PWM. By using interleaved converters, an overall reduction of the boost inductor can be obtained, reducing switching losses without increasing current

  5. Microbial fuel cell energy harvesting using synchronous flyback converter

    NASA Astrophysics Data System (ADS)

    Alaraj, Muhannad; Ren, Zhiyong Jason; Park, Jae-Do

    2014-02-01

    Microbial Fuel Cells (MFCs) use biodegradable substrates, such as wastewater and marine sediments to generate electrical energy. To harvest more energy from an MFC, power electronic converters have recently been used to replace resistors or charge pumps, because they have superior controllability on MFC's operating point and higher efficiency in energy storage for different applications. Conventional diode-based energy harvesters suffer from low efficiency because of the energy losses through the diode. Replacing the diode with a MOSFET can reduce the conduction loss, but it requires an isolated gate signal to control the floating secondary MOSFET, which makes the control circuitry complex. This study presents a new MFC energy harvesting regime using a synchronous flyback converter, which implements a transformer-based harvester with much simpler configuration and improves harvesting efficiency by 37.6% compared to a diode based boost converter, from 33.5% to 46.1%. The proposed harvester was able to store 2.27 J in the output capacitor out of 4.91 J generated energy from the MFC, while the boost converter can capture 1.67 J from 4.95 J.

  6. Design of a simple high-power-factor rectifier based on the flyback converter

    Microsoft Academic Search

    Robert Erickson; Michael Madigan; Sigmund Singer

    1990-01-01

    An equivalent circuit model for the discontinuous conduction mode flyback converter based on the loss-free resistor concept is presented. This simple model correctly describes the basic power processing properties of the converter, including input port resistor emulation, output port power source characteristics, and control characteristics. Based on this model, steady-state design equations are described and are used in a design

  7. A zero-current-switching PWM flyback converter with a simple auxiliary switch

    Microsoft Academic Search

    Henry Shu-Hung Chung; S. Y. R. Hui; Wei-Hua Wang

    1999-01-01

    A simple and effective approach of turning an isolated hard-switched converter design into a soft-switched one is presented. By adding an auxiliary winding, switch and small capacitor to the conventional pulsewidth modulation (PWM) isolated flyback converter, all switches and diodes are softly turned on and off. No extra active or passive voltage clamp circuit is needed to suppress voltage stress

  8. Design and Analysis of an Interleaved Flyback–Forward Boost Converter With the Current Autobalance Characteristic

    Microsoft Academic Search

    Dong Wang; Xiangning He; Jianjiang Shi

    2010-01-01

    An interleaved flyback-forward boost converter is proposed in this paper. The switched capacitors are used to realize the controllable voltage source function and balance the currents of the interleaved two phases without an additional current-sharing module. Voltage lift function of the switched capacitor also reduces the turns ratio of the transformers and alleviates the voltage stresses of the output diodes.

  9. A Digitally Controlled DCM Flyback Converter With a Low-Volume Dual-Mode Soft Switching

    E-print Network

    Prodiæ, Aleksandar

    A Digitally Controlled DCM Flyback Converter With a Low-Volume Dual-Mode Soft Switching Circuit conduction mode (DCM). The new ZVS/ZCS solution provides soft switching feature and high efficiency throughout the whole operating range. It also requires smaller components than other soft switching solutions

  10. Adaptive off-time control for variable-frequency, soft-switched flyback converter at light loads

    Microsoft Academic Search

    Yuri Panov; Milan M. Jovanovic

    2002-01-01

    The soft switching of a flyback converter can be achieved by operating the circuit in the critical conduction mode. However, the critical-mode operation at light loads cannot be maintained due to a very high switching frequency and the loss of the output voltage regulation. A control which regulates the output down to the zero load and maintains soft switching at

  11. Cascaded resonant bridge converters

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  12. Pulse Current Regenerative Resonant Snubber-Assisted Two-Switch Flyback Type ZVS PWM DC-DC Converter

    NASA Astrophysics Data System (ADS)

    Inaba, Claudio Y.; Konishi, Yoshihiro; Nakaoka, Mutsuo

    In this paper, a two-switch high frequency flyback transformer type zero voltage soft switching PWM DC-DC converter using IGBTs is proposed. Effective applications for this power converter can be found in auxiliary power supplies of rolling stock transportation and electric vehicles. This power converter is basically composed of two active power switches and a flyback high frequency transformer. In addition to these, two passive lossless snubbers with power regeneration loops for energy recovery, consisting of a three winding auxiliary high frequency transformer, auxiliary capacitors and diodes are introduced to achieve zero voltage soft switching from light to full load conditions. Furthermore, this power converter has some advantages such as low cost circuit configuration, simple control scheme and high efficiency. Its operating principle is described and to determine circuit parameters, some practical design considerations are discussed. The effectiveness of the proposed power converter is evaluated and compared with the hard switching PWM DC-DC converter from an experimental point of view and the comparative electromagnetic conduction and radiation noise characteristics of both DC-DC power converter circuits are also depicted.

  13. Utilization of an active-clamp circuit to achieve soft switching in flyback converters

    Microsoft Academic Search

    R. Watson; F. C. Lee; G. C. Hua

    1994-01-01

    Flyback derived topologies are attractive because of their relative simplicity when compared with other topologies used in low power applications. Incorporation of active-clamp circuitry into the flyback topology serves to recycle transformer leakage energy while minimizing switch voltage stress. The addition of the active-clamp circuit also provides a mechanism for achieving zero-voltage-switching (ZVS) of both the main and auxiliary-switches. ZVS

  14. Utilization of an active-clamp circuit to achieve soft switching in flyback converters

    Microsoft Academic Search

    R. Watson; F. C. Lee; G. C. Hua

    1996-01-01

    Flyback derived power convertor topologies are attractive because of their relative simplicity when compared with other topologies used in low power applications. Incorporation of active-clamp circuitry into the flyback topology serves to recycle transformer leakage energy while minimizing switch voltage stress. The addition of the active-clamp circuit also provides a mechanism for achieving zero-voltage-switching (ZVS) of both the primary and

  15. Soft-switching techniques for PWM full bridge converters

    Microsoft Academic Search

    Xinbo Ruan; Yangguang Yan

    2000-01-01

    This paper proposes a family of modulation strategies for PWM full bridge converter including nine modulation strategies, which can be classified into two kinds according to the turn-off sequence of the two power switches in the oblique diagonal line of the two bridge legs. The concept of leading leg and lagging leg is introduced to realize soft-switching for PWM full

  16. A novel soft-switching full-bridge converter

    Microsoft Academic Search

    Chia-Wei Lee; Ching-Shan Leu

    2009-01-01

    Inserting an auxiliary switch to the conventional hard-switch full-bridge topology, a novel soft-switching full-bridge converter is proposed. Instead of the main switches, the auxiliary switch is pulse-width modulated to regulate the output voltage and soft-switching operation of the main switches can be easily achieved over full line and load ranges. Consequently, the reduced switching losses can be compensated for the

  17. A dual bridge high current DC-to-DC converter with soft switching capability

    Microsoft Academic Search

    Nasser H. Kutkut; Glen Luckjiff; Deepak M. Divan

    1997-01-01

    This paper presents a dual bridge high current DC-to-DC converter with soft switching capability. The proposed dual bridge power supply is based on the two switch isolated forward converter. Unlike conventional dual bridge forward converters, phase shift control is employed to regulate the output voltage and achieve soft switching. In addition, a single high frequency power transformer is proposed to

  18. A power factor corrected PMBLDCM drive for air-conditioner using bridge converter

    Microsoft Academic Search

    Sanjeev Singh; Bhim Singh

    2010-01-01

    This paper aims at a power factor corrected (PFC) buck bridge DC-DC converter for a permanent magnet brushless DC motor (PMBLDCM) for an air conditioner. This PFC converter is fed from a single-phase AC mains through a diode bridge rectifier (DBR) and connected to a voltage source inverter (VSI) feeding the PMBLDCM. The Speed of the proposed PMBLDCM drive is

  19. Dynamic analysis of loss limited switching full bridge DC-DC converter with multimodal control

    Microsoft Academic Search

    A. R. Bendre; G. Venkataramanan; D. M. Divan

    2002-01-01

    This paper presents a new variable frequency multimodal control strategy for loss-limited full bridge DC-DC power converters. This controller extends converter operating region and lowers magnetic component core loss. Steady state and dynamic analyses of the converter operation in the various modes are presented

  20. Optimizing dual half bridge converter for full range soft switching and high efficiency

    Microsoft Academic Search

    Hamid Daneshpajooh; Alireza Bakhshai; Praveen Jain

    2011-01-01

    This paper is concerned with finding the optimum operating points of a soft-switched dual half bridge bidirectional dc-dc converter. Phase shift modulation (?) with a fixed duty cycle is used to control the converter (1) but the soft switching range is limited. In this paper the soft switching range and efficiency of the converter are highly improved by recruiting duty

  1. Tri-Modal Half-Bridge Converter Topology for Three-Port Interface

    Microsoft Academic Search

    Hussam Al-Atrash; Feng Tian; Issa Batarseh

    2007-01-01

    This letter proposes a novel converter topology that interfaces three power ports: a source, a bidirectional storage port, and an isolated load port. The proposed converter is based on a modified version of the isolated half-bridge converter topology that utilizes three basic modes of operation within a constant-frequency switching cycle to provide two independent control variables. This allows tight control

  2. Digital control of a ZVS full-bridge DC-DC converter

    Microsoft Academic Search

    P. F. Kocybik; K. N. Bateson

    1995-01-01

    The paper describes the design and realization of a digital controller for a DC-DC power converter with zero-voltage switching (ZVS). The chosen power converter, usually called the phase-shifted bridge, is valuable because it combines advantages from both conventional PWM and resonant-mode power converters. It is therefore an important topology for investigating the advantages of digital control for DC-DC power converters.

  3. Implicit Model Predictive Control of a Full Bridge DC–DC Converter

    Microsoft Academic Search

    Yanhui Xie; Reza Ghaemi; Jing Sun; James S. Freudenberg

    2009-01-01

    This paper presents a model predictive control (MPC)-based approach for a full bridge dc-dc converter of a fuel cell power system. The objective of the proposed control algorithm is to regulate the output voltage without violating the peak current constraint. We first develop a large signal dynamic model for the full bridge dc-dc converter. The peak current protection requirement is

  4. A Pulse-Frequency-Modulated Full-Bridge DC\\/DC Converter With Series Boost Capacitor

    Microsoft Academic Search

    Yong-Saeng Shin; Chang-Seop Kim; Sang-Kyoo Han

    2011-01-01

    The conventional zero-voltage switching phase-shift full-bridge (ZVS PSFB) converter has a large circulating energy during the freewheeling interval caused by the small duty cycle, which could increase the primary-side conduction losses, the turn-off switching losses of lagging-leg switches, and the current ripple through the output inductor. To overcome these problems, this paper proposes a new pulse-frequency-modulated full-bridge direct-current (dc)\\/dc converter

  5. Design of Robust Digital PID Controller for H-Bridge Soft-Switching Boost Converter

    Microsoft Academic Search

    Veerachary Mummadi

    2011-01-01

    In this paper, a robust digital proportional-integral- derivative (PID) controller is proposed for the H-bridge soft- switching boost converter (HSBC). This digital PID controller is designed to ensure load voltage regulation as well as to give robust performance with step loads and source rejection. The mathemat- ical models of the H-bridge boost converter are formulated, using the system identification tool,

  6. Performance characterization of a high-power dual active bridge DC-to-DC converter

    Microsoft Academic Search

    Mustansir H. Kheraluwala; Randal W. Gascoigne; Deepakraj M. Divan; Eric D. Baumann

    1992-01-01

    The performance of a high-power, high-power-density DC-to-DC converter based on the single-phase dual active bridge (DAB) topology is described. The dual active bridge converter has been shown to have very attractive features in terms of low device and component stresses, small filter components, low switching losses, high power density and high efficiency, bidirectional power flow, buck-boost operation, and low sensitivity

  7. A high performance dual output dc-dc converter combined the phase shift full bridge and LLC resonant half bridge with the shared lagging leg

    Microsoft Academic Search

    Yu Chen; Xuejun Pei; Li Peng; Yong Kang

    2010-01-01

    A new dual output dc-dc converter is proposed in this paper. The first output works as a conventional full bridge converter; by connecting a LLC resonant tank to the lagging leg, a half bridge resonant converter is structured, and the second output is obtained. The first output is regulated by the phase shift and the second output by the switching

  8. A soft-switched, full-bridge boost converter employing an active-clamp circuit

    Microsoft Academic Search

    R. Watson; F. C. Lee

    1996-01-01

    A new full-bridge, active-clamp boost converter is proposed for single-phase high power PFC applications and applications requiring transformer isolation. The active-clamp network serves to limit bridge switch turn-off voltage overshoot and enable the energy stored in the transformer leakage inductance to be used for zero-voltage switching. PWM phase-shift control of the bridge switches is utilized to obtain zero-current switching for

  9. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    Microsoft Academic Search

    Woo-Young Choi

    2010-01-01

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC–DC converter and a single-phase full-bridge DC–AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC–DC converter. The proposed step-up DC–DC converter reduces the switching losses

  10. A Universal Functional Electrical Stimulator Based on Merged Flyback-SC Circuit

    E-print Network

    Prodiæ, Aleksandar

    -capacitor (SC) converters. The flyback steps up battery voltage and provides galvanic isolation. The following of the output current pulses is performed through integrated digital voltage-programmed current mode control devices can be divided in two categories: voltage and current controlled. The voltage controlled

  11. Implementation of digitally controlled phase shift full bridge converter for server power supply

    Microsoft Academic Search

    Je-Hyung Cho; Hyun-Wook Seong; Shin-Myung Jung; Jin-Sik Park; Gun-Woo Moon; Myung-Joong Youn

    2010-01-01

    The digital controller of the phase-shift full bridge converter for a server power supply is designed and implemented in this paper. Analog controllers are replaced by single MCU (micro controller unit) that not only manages the protection or the operational flow of a power supply but also controls the converter. Voltage mode controller is designed based on the z-domain small

  12. Small-signal model for current mode control full-bridge phase-shifted ZVS converter

    Microsoft Academic Search

    Xu Xiaofeng

    2000-01-01

    In this paper, the small-signal model of a current mode control full-bridge phase-shifted ZVS PWM converter is derived based on the small-signal model of the converter. Through the transformation of the current mode small-signal model into the respective transfer function model, a simplified close loop current mode small-signal transfer function of the converter is obtained. By using the derived small-signal

  13. Small signal model for Boost Phase-shifted Full Bridge converter in high voltage application

    Microsoft Academic Search

    Xin Zhang; Xinbo Ruan; Wu Chen

    2009-01-01

    Boost phase-shifted (PS) full-bridge (FB) converter is a typical converter in high voltage application. Due to the requirement of high voltage insulator, its transformer is often designed with more leakage inductor and inter-layer capacitor. Considering leakage inductor and inter-layer capacitor's effect, accurate model of Boost PS FB converter is established. The difference between this model and the conventional model is

  14. Computer-assisted modeling of the phase-modulated full bridge converter

    Microsoft Academic Search

    P. Maranesi; G. Naummi

    1992-01-01

    The small-signal dynamics of the phase-shifted full bridge DC\\/DC power converter is described with the aid of the computer program FREDOMSIM. The inherent inner feedback loop is open and the circuit is modeled as the connection of a snubbered full bridge with an output low pass filter, providing a third order system. The procedure looks suitable for modeling other switching

  15. Dynamic modelling of phase-shifted full-bridge series resonant converter

    Microsoft Academic Search

    W. C. So; Y. S. Lee; C. K. Tse

    1997-01-01

    Dynamic models for phase-shifted full-bridge series resonant converters operating above or below resonance are developed. While steady-state operation of such converters has been studied previously, there has been no detailed report so far on their dynamic behaviour. The models derived in this paper are suitable for low-frequency small-signal analyses, which are useful to engineers for the design of feedback compensation.

  16. Full bridge ZCS PWM converter for high-voltage high-power applications

    Microsoft Academic Search

    CHRIS IANNELLO; SHIGUO LUO; ISSA BATARSEH

    2002-01-01

    This paper presents a comprehensive study of a full bridge (FB) zero-current switched (ZCS) PWM converter which is suitable for high-voltage and high-power DC application that achieves ZCS for all active switches, and zero-voltage-switched (ZVS) operation for all diodes on the high voltage side. The given converter utilizes component parasitic parameters, particularly for the high-voltage transformer, and employs fixed-frequency phase-shift

  17. A PWM full-bridge converter with load independent soft-switching capability

    Microsoft Academic Search

    Gerry Moschopoulos; Praveen Jain

    2000-01-01

    Although the zero-voltage switched (ZVS) pulsewidth modulated (PWM) full-bridge (FB) converter can operate with soft-switching and fixed frequency control it loses its ZVS capability under light-load conditions. This paper examines the use of auxiliary circuits attached to the bottom switches of the standard ZVS-PWM-FB converter as a means of extending the ZVS range. The auxiliary circuits, each consisting of an

  18. Soft-switching of IGBTs with the help of MOSFETs in bridge-type converters

    Microsoft Academic Search

    Yimin Jiang; Guichao Hua; Eric Yang; Fred C. Lee

    1993-01-01

    For high power switching power converters, IGBTs are more attractive than MOSFETs due to the lower conduction losses and lower cost. However, the slow turn-on and turn-off characteristics, especially the turn-off current tail of the IGBTs, cause severe switching losses, thus limiting the switching frequency. Several bridge-type converters which achieve soft-switching of IGBTs with the help of the fast-switching MOSFETs

  19. A new mode changeable full bridge dc\\/dc converter for wide input voltage range

    Microsoft Academic Search

    Yong-Saeng Shin; Sung-Soo Hong; Dong-Joong Kim; Dong-Sung Oh; Sang-Kyoo Han

    2011-01-01

    Generally, a zero voltage switching (ZVS) phase shift full bridge (PSFB) converter is suitable for high power density\\/high efficiency application and its efficiency is maximized at 50% duty cycle. However, the steady state duty cycle is as small as approximately 30% at full load and nominal input voltage conditions which is because the PSFB must be designed to be ensure

  20. A pulse frequency modulated full bridge DC\\/DC converter with series boost capacitor

    Microsoft Academic Search

    Yong-Saeng Shin; Chung-Wook Roh; Sung-Soo Hong; Sang-Kyoo Han

    2010-01-01

    The conventional Zero Voltage Switching (ZVS) Phase Shift Full Bridge converter(PSFB) has large circulating energy during freewheeling interval caused by the small duty cycle, which could increase the primary side conduction losses, turn off switching losses of lagging leg switches and current ripple through the output inductor. To overcome these problems, this paper proposes a new pulse frequency modulated full

  1. VSS approach to a full bridge buck converter used for AC sine voltage generation

    Microsoft Academic Search

    F. Boudjema; M. Boscardin; P. Bidan; J. C. Marpinard; M. Valentin; J. L. Abatut

    1989-01-01

    The authors present an application of variable structure systems (VSS) theory, and the associated sliding mode, to a full bridge buck converter used to produce an AC sine voltage. To design a sliding mode controller, the pole assignment method is used. The equivalent control method makes it possible to determine the existence of the sliding regime in the state space.

  2. Current-Fed Full Bridge Converters for Fuel Cell Systems Connected to the Three Phase Grid

    Microsoft Academic Search

    Malte Mohr; F.-W. Fuchs

    2006-01-01

    Fuel cells for low or medium power deliver comparatively low voltages compared to the mains voltage at high currents. A high dc-link voltage is needed to feed in electrical energy from fuel cells to the mains via a voltage source inverter. In the considered higher power range the full bridge dc-dc converter circuit is an appropriate solution. In this paper

  3. A Soft-Switched Square-Wave Half-Bridge DC-DC Converter

    E-print Network

    A Soft-Switched Square-Wave Half-Bridge DC-DC Converter C. R. Sullivan S. R. Sanders From IEEE, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. #12;Soft-Switched soft switching and control. The square current and voltage waveforms result in low voltage and current

  4. A novel ZVZCS full-bridge PWM DC-DC converter with active voltage clamp and energy recovery circuit

    Microsoft Academic Search

    Tiecheng Sun; Xueguang Zhang; Pinghua Tang; Lin Mei

    2005-01-01

    An improved zero voltage and zero current switching (ZVZCS) full-bridge (FB) PWM DC-DC converter is proposed. The new converter overcomes drawbacks such as voltage ringing and voltage overshoot in conventional ZVZCS converter. An auxiliary circuit consists of auxiliary switcher, clamping capacitor, diode rectifier and energy recovery transformer. The auxiliary circuit alleviates the voltage ringing and voltage overshoot in secondary side

  5. A novel zero-Voltage and zero-current-switching full-bridge PWM converter

    Microsoft Academic Search

    TingTing Song; Nianci Huang

    2005-01-01

    A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge pulse-width modulation converter is proposed. The ZCS condition of the lagging-leg is obtained by a simple secondary auxiliary circuit resetting the primary current during the freewheeling stage. The auxiliary circuit's capacitor is charged by the center tape of the secondary through a diode, and the capacitor's voltage is clamped through another diode to

  6. FPGA-based digital current mode controller for phase-shifted full-bridge PWM converter

    Microsoft Academic Search

    Jeong-Gyu Lim; Se-Kyo Chung; Yujin Song

    2009-01-01

    This paper deals with a digital current mode controller for a phase-shifted full-bridge PWM converter (PSFBC) using a field programmable gate arrays (FPGA). The proposed digital controller consists of a digital PWM generator with a switching frequency of 195 kHz and an average current mode controller based on the discrete-time domain model, which is implemented in a fully hardware manner

  7. A full bridge ZCS PWM converter for high voltage and high power applications

    Microsoft Academic Search

    Chris Iannello; Shiguo Luo; Issa Batarseh

    2000-01-01

    This paper presents the detailed analysis of a full bridge zero current switched (FB-ZCS) PWM converter that is suitable for high-voltage and high-power DC applications. It exhibits excellent ability to incorporate parasitic parameters, zero current turn-off characteristics for all active switches and ZVS operation for all diodes on the high voltage side. Based on the features of high-voltage power supplies,

  8. Full bridge soft-switching phase-shifted PWM DC-DC converter using tapped inductor filter

    Microsoft Academic Search

    Serguei Moisseev; Shinji Sato; Satoshi Hamada; Mutsuo Nakaoka

    2003-01-01

    In this paper, a novel high frequency transformer linked full-bridge type soft-switching phase-shift PWM control scheme DC-DC power converter is presented. A tapped inductor filter is implemented in the proposed soft-switching converter topology to achieve wide load variation range soft-switching PWM constant frequency operation of the DC-DC converter, to minimize circulating current. The presented converter operates with ZVS for leading

  9. Novel Full-bridge ZVS DC-DC Converter with an Clamp Diodes

    NASA Astrophysics Data System (ADS)

    Guangqun, Nan; Xue, Hu

    The two arms of this converter all work at zero-voltage switching condition, that bring many advantages, such as little loss of power, simple control, etc. But these also exists some problems, such as parasitic oscillation on the output rectifier diodes. A novel full-bridge ZVS PWM DC-DC converter which adopts two clamping diodes in the first side of the transformer is proposed to reduce the parasitic oscillation in this paper. In this paper, It heavily analyzes the realization process of their soft-switching and the reason of related issues and solution, we establishes simulation model and simulates using orCAD. Finally,a 5 kW ZVS PWM DC-DC converter Prototype in that TMS320F2812 is the core controlled chip has been set up, and the experiments showed us the validation of the correlative theory.

  10. The Research of Modeling and Simulation for Phase-shifted Full-bridge ZVS DC \\/ DC Converter

    Microsoft Academic Search

    Hu Xuezhi; Nan Guangqun

    2009-01-01

    On the basis of the analysis of phase-shifted full-bridge ZVS PWM converter, Corresponding small-signal model is build using of state-space averaging method and the traditional Buck circuit model, Thereof, control block diagram of the system and transfer function are derived, Voltage single-loop control system is designed on the basis of small-signal model of phase-shifted full-bridge ZVS converter, Thus, the system

  11. Analysis and Implementation of a High Efficiency, Interleaved Current-fed Full Bridge Converter for Fuel Cell System

    Microsoft Academic Search

    Xin Kong; A. M. Khambadkone

    2005-01-01

    An interleaved current-fed full bridge DC\\/DC converter is proposed in this paper which shows good electrical compatibility to fuel cells inherent characteristics. By interleaving two isolated current-fed full bridge converters with parallel input and series output connection, input current ripple can be further reduced. In addition the size of the magnetizing components and current stress of the semiconductor devices on

  12. Soft-switching PWM full-bridge DC-DC converter with energy recovery transformer and auxiliary passive lossless snubbers

    Microsoft Academic Search

    Yung-Fu Huang; Chih-Wen Liu; Yoshihiro Konishi

    2007-01-01

    This paper proposes a novel soft-switching full-bridge PWM DC-DC converter using passive regenerative snubber. The newly proposed circuit topology is composed of a full-bridge converter with a high frequency linked transformer and passive snubbers configured with energy regenerative circuit and controlled under the conventional PWM actions to prevent freewheeling current. The leakage inductance of main transformer (Tm) helps to achieve

  13. High frequency transformer-assisted passive soft switching PWM DC-DC converter with energy recovery for compact auxiliary power supply in rolling stock transportation

    Microsoft Academic Search

    Claudio Y. Inaba; Yoshihiro Konishi; Mutsuo Nakaoka

    2003-01-01

    In this paper, a two-switch high frequency flyback type zero voltage soft switching PWM DC-DC converter using IGBTs is proposed. Effective applications for this power converter can be found in auxiliary power supplies of rolling stock transportation and electric vehicles. This power converter is basically composed of two active power switches and a flyback high frequency transformer. In addition to

  14. Novel zero-voltage and zero-current-switching (ZVZCS) full bridge PWM converter using a simple auxiliary circuit

    Microsoft Academic Search

    Jung G. Cho; Ju W. Baek; Chang Y. Jeong; Dong W. Yoo; Hong S. Lee; Geun H. Rim

    1998-01-01

    A novel zero voltage and zero current switching (ZVZCS) full bridge (FB) PWM power converter is presented to simplify the circuits of the previously presented ZVSCS power converters. A simple auxiliary circuit which consists of one small capacitor and two small diodes is added in the secondary to provide ZVZCS conditions to primary switches as well as to clamp secondary

  15. Analysis and Implementation of a High Efficiency, Interleaved Current-Fed Full Bridge Converter for Fuel Cell System

    Microsoft Academic Search

    Xin Kong; Ashwin M. Khambadkone

    2007-01-01

    An interleaved current-fed full bridge (ICFFB) dc-dc converter is proposed in this paper that has low input current ripple to meet the fuel cell demands. By interleaving two isolated CFFB converters with parallel input and series output connection, both input current ripple and output voltage ripple can be reduced. In addition, the size of the magnetic components and current stress

  16. High Efficiency Full Bridge Current-Fed DC-DC Converter for a Fuel Cell Power System

    Microsoft Academic Search

    O. A. Ahmed; J. A. M. Bleijs

    A new active clamp current-fed full bridge isolated DC-DC converter topology for fuel cell applications is presented. Comparison results show that this topology improves the efficiency over a wide load range. Using small signal analysis the AC equivalent circuit and transfer functions have been derived. These show that the dynamic response for the proposed converter is more benign than that

  17. Implementation of a Full Bridge Series-Parallel Resonant DC-DC converter using ANN and SSM controllers

    Microsoft Academic Search

    Zahra Malekjamshidi; Mohammad Jafari; Mohsen Imanieh

    2011-01-01

    In this paper, two methods of control for high-voltage Full Bridge Series-Parallel Resonant (FBSPR) DC-DC converter are proposed and the results are compared. Soft switching operation using Zero Current Switching (ZCS) and Zero Voltage Switching (ZVS) technologies is employed to decrease the losses and optimize the efficiency of converter. The way of obtaining small-signal model of FBSPR converter using the

  18. Dynamic analysis of loss-limited switching full-bridge DC-DC converter with multimodal control

    Microsoft Academic Search

    Ashish Bendre; Giri Venkataramanan; Deepak Divan

    2003-01-01

    Full-bridge DC-DC converters with one soft-switched leg and one hard-switched leg have been introduced as an attractive approach for realizing high-frequency power conversion at power levels greater than 100 kW. This paper presents a new variable-frequency multimodal control strategy for these converters for obtaining optimal operating characteristics. The controller extends the soft-switching operating region of the converter while lowering magnetic

  19. A Fully Digital Controlled 3KW, Single-Stage Power Factor Correction Converter Based on Full-Bridge Topology

    Microsoft Academic Search

    Hang Li-jun; Yang Yue-feng; Su Bin; Lu Zheng-yu; Qian Zhao-ming

    2006-01-01

    This paper deals with a 3 KW power factor correction (PFC) circuit based on the isolated full-bridge (FB) converter. The operation principle of the very converter is simply analyzed. Digital design consideration based on the small-signal dynamic modeling of the isolated PFC converter is specified in this paper. Implementation strategy and cost effectiveness of digital control for the single-stage PFC

  20. Study on optimum design procedure of charger based on full-bridge phase-shifted ZVZCS converter

    Microsoft Academic Search

    Niu Liyong; Jiang Jiuchun; Zhang Weige

    2008-01-01

    An optimum design procedure of an Electric Vehicle charger based on a full-bridge phase-shifted zero-voltage and zero-current switching (FB-PS-ZVZCS) dc-dc converter is proposed. The converter uses a small capacitor and two small diodes to form the clamp circuit, which makes the converter simple and easy to control. According to the analysis of the operation principles, several conclusions about the influences

  1. A Three-phase Dual Active Bridge Bidirectional ZVS DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Xuan, Zhang; Shenghua, Huang; Guoyun, Ning

    This paper discusses the detailed operations of a three-phase dual active bridge bidirectional zero-voltage switching (ZVS) DC/DC converter (TPDAB) which transfers a bidirectional power flow between a 12 V net and a high voltage DC net. The converter is controlled by phase-shift-modulation (PSM) with a fixed duty cycle D=1/3. It features isolation, smoother drawing and injecting current from the 12 V net, smaller capacitances, smaller switch current stress, ZVS over a wide range, high efficiency and a large power handling capability. The mathematic model is analyzed. The soft-switching principle is described and its ZVS criterias are derived. The simulation and experimental results are provided to verify the theoretical analysis.

  2. Comparison between phase-shift full-bridge converters with noncoupled and coupled current-doubler rectifier.

    PubMed

    Tsai, Cheng-Tao; Su, Jye-Chau; Tseng, Sheng-Yu

    2013-01-01

    This paper presents comparison between phase-shift full-bridge converters with noncoupled and coupled current-doubler rectifier. In high current capability and high step-down voltage conversion, a phase-shift full-bridge converter with a conventional current-doubler rectifier has the common limitations of extremely low duty ratio and high component stresses. To overcome these limitations, a phase-shift full-bridge converter with a noncoupled current-doubler rectifier (NCDR) or a coupled current-doubler rectifier (CCDR) is, respectively, proposed and implemented. In this study, performance analysis and efficiency obtained from a 500?W phase-shift full-bridge converter with two improved current-doubler rectifiers are presented and compared. From their prototypes, experimental results have verified that the phase-shift full-bridge converter with NCDR has optimal duty ratio, lower component stresses, and output current ripple. In component count and efficiency comparison, CCDR has fewer components and higher efficiency at full load condition. For small size and high efficiency requirements, CCDR is relatively suitable for high step-down voltage and high efficiency applications. PMID:24381521

  3. Bridges

    USGS Multimedia Gallery

    Bridges from top to bottom: Expressway Bridge, Liberty Memorial Bridge, Burlington Northern SantaFe Railway Bridge, and Interstate 94 Grant Marsh Bridge. Photo taken by USGS personnel on a Civil Air Patrol flight....

  4. 3boost: A High-Power Three-Phase Step-Up Full-Bridge Converter for Automotive Applications

    Microsoft Academic Search

    Giovanni Franceschini; Emilio Lorenzani; Matteo Cavatorta; Alberto Bellini

    2008-01-01

    This paper describes a simple dc-dc step-up converter topology for switch-mode dc power supplies. The proposed configuration is well suited for high-power applications with battery supply. In the automotive framework, the push-pull architecture is the most widespread. However, as power increases, the use of a full-bridge architecture is mandatory. This paper presents a full-bridge architecture where the traditional single-phase transformer

  5. A zero-voltage and zero-current switching full bridge DC-DC converter with transformer isolation

    Microsoft Academic Search

    Seong-Jeub Jeon; Gyu-Hyeong Cho

    2001-01-01

    A new primary-side-assisted zero-voltage and zero-current switching full bridge DC-DC converter with transformer isolation is proposed. The proposed DC-DC converter uses only one auxiliary transformer and two diodes to obtain ZCS for the leading leg. It has a simple and robust structure, and load current control capability even in short circuit conditions, The possibility of magnetic saturation due to asymmetricity

  6. Zero-voltage-zero-current switching in high-output-voltage full bridge PWM converters using the interwinding capacitance

    Microsoft Academic Search

    Djordje Garabandic; W. G. Dunford; M. Edmunds

    1998-01-01

    A novel zero-voltage and zero-current switching (ZVZCS) full-bridge (FB) pulse width modulated (PWM) converter is proposed. The new converter uses the interwinding capacitance and a small primary side inductor to achieve a zero-current-zero-voltage turn off and a zero-current turn on of the passive-to-active leg transistors. The turn off of the active-to-passive leg transistors is with zero-voltage and the turn on

  7. Novel zero-voltage and zero-current-switching full-bridge PWM converter using a simple auxiliary circuit

    Microsoft Academic Search

    Jung-Goo Cho; Ju-Won Baek; Chang-Yong Jeong; Geun-Hie Rim

    1999-01-01

    A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge pulsewidth modulation converter is presented to simplify the circuits of the previously presented ZVSCS converters. A simple auxiliary circuit, which consists of one small capacitor and two small diodes, is added in the secondary to provide ZVZCS conditions to primary switches, as well as to clamp secondary rectifier voltage. The additional clamp circuit

  8. Zero-voltage-zero-current switching in high-output-voltage full-bridge PWM converters using the interwinding capacitance

    Microsoft Academic Search

    Djordje Garabandic; William G. Dunford; Mark Edmunds

    1999-01-01

    A novel zero-voltage and zero-current-switching (ZVZCS) full-bridge (FB) pulsewidth-modulated (PWM) power converter is proposed. The new converter uses the interwinding capacitance and a small primary-side inductor to achieve a zero-current-zero-voltage turn off and a zero-current turn on of the passive-to-active leg transistors. The turn off of the active-to-passive leg transistors is with zero voltage, and the turn on is with

  9. A ZCS Lossless Snubber Cells-Applied Half-Bridge Bidirectional DC—DC Converter for Automotive Electric Power Systems

    Microsoft Academic Search

    Tomokazu Mishima; Eiji Hiraki; Toshihiko Tanaka

    2006-01-01

    A new type of bidirectional DC—DC converter for electric power systems in advanced electric vehicles is proposed in this paper. This converter consists of half-bridge circuits with a high frequency transformer, which is well applicable as an interface between a high-voltage DC bus line and a low-voltage power source. In order to reduce the switching loss, newly developed ZCS loss-less

  10. A High-Power Input-Parallel Output-Series Buck and Half-Bridge Converter and Control Methods

    Microsoft Academic Search

    Qing Du; Bojin Qi; Tao Wang; Tao Zhang; Xiao Li

    2012-01-01

    The two-switch cascade converter is the most appropriate solution for efficient high-power applications among the existing converter topologies. However, the cascade structure and the nonlinear dc gain of boost circuit are more likely to cause severe oscillations if the criterion for the selection of the operation mode is chosen improperly during step-up\\/step-down transition. A novel high-power input-parallel output-series buck-half-bridge (IPOSBHB)

  11. Redesign of the H-Bridge Switch Plate of the SNS High Voltage Converter Modulator

    SciTech Connect

    Kemp, M.A.; Burkhart, C.; Nguyen, M.N.; /SLAC; Anderson, D.E.; /Oak Ridge

    2009-05-07

    The 1-MW High Voltage Converter Modulators [1] have operated in excess of 250,000 hours at the Spallation Neutron Source. Increased demands on the accelerator performance require increased modulator reliability. An effort is underway at SLAC National Accelerator Laboratory to redesign the modulator H-bridge switch plate with the goals of increasing reliability and performance [2]. The major difference between the SLAC design and the existing design is the use of press-pack IGBTs. Compared to other packaging options, these IGBTs have been shown to have increased performance in pulsed-power applications, have increased cooling capability, and do not fragment and disassemble during a fault event. An overview of the SLAC switch plate redesign is presented. Design steps including electrical modeling of the modulator and H-bridge, development of an integrated IGBT clamping mechanism, and fault tests are discussed. Experimental results will be presented comparing electrical performance of the SLAC switch plate to the existing switchplate under normal and fault conditions.

  12. Dynamic analysis of switched reluctance motor in two different control strategies based on three-phase bridge converter

    Microsoft Academic Search

    Jingjing Peng; Zhiquan Deng; Xiaoyuan Chen; Zeyuan Liu; Xiaolin Wang; Yuanyuan Wu; Jun Cai

    2009-01-01

    In this paper, two kinds of control strategies applied to a switched reluctance motor (SRM) with 12\\/8 teeth configuration have been analyzed based on a three-phase bridge converter. The first strategy is that the three phase SRM windings have to be connected in delta, with a separate diode connected in series with each phase, which is possible to control the

  13. An Alternative Energy Recovery Clamp Circuit for Full-Bridge PWM Converters With Wide Ranges of Input Voltage

    Microsoft Academic Search

    Honnyong Cha; Lihua Chen; Rongjun Ding; Qingsong Tang; Fang Zheng Peng

    2008-01-01

    A full-bridge DC-DC converter employing a diode rectifier in the output experiences a severe voltage overshoot and oscillation problem across the diode rectifier caused by interaction between junction capacitance of the rectifier diode and leakage inductance of the transformer. The pronounced reverse-recovery current of high-power diodes significantly contributes to these issues by increasing power lossand voltage overshoot. Conventional energy recovery

  14. Analysis on Anti-Grid Voltage Disturbance Capacity of Phase-Shifted Full-Bridge ZVS DC\\/DC Converter

    Microsoft Academic Search

    Guoxin Li; Caoyuan Ma; Chen Zhao; Guifu Du; Yanan Zhao

    2010-01-01

    Based on the background of battery charging system, in this paper, the small-signal equivalent circuit model of phase-shifted full-bridge ZVS DC\\/DC converter is established, then its transfer function is derived, and a single closed-loop voltage-mode controller is designed. In order to analyze anti-grid voltage disturbance capacity, transfer function of audio susceptibility is presented, and the anti-grid disturbance capacity in open-loop

  15. A ZCS Current-Fed Full-Bridge PWM Converter With Self-Adaptable Soft-Switching Snubber Energy

    Microsoft Academic Search

    Huai Wang; Qian Sun; Henry Shu Hung Chung; Saad Tapuchi; Adrian Ioinovici

    2009-01-01

    A new soft-switched, current-driven full-bridge converter is presented. The structure utilizes a simple snubber formed by two unidirectional switches and a capacitor to realize soft-switching operation over a wide line and load range. All primary-side switches are operated with zero-current switching (ZCS) and the snubber switches are operated with zero-voltage switching. The energy used for soft-switching is self-adaptable. For a

  16. Digital load share controller design of paralleled phase-shifted full-bridge converters referencing the highest current

    Microsoft Academic Search

    Hyun-Wook Seong; Je-Hyung Cho; Gun-Woo Moon; Myung-Joong Youn

    2010-01-01

    For a high power demand and N+1 redundancy system, this paper presents a digital load share (LS) controller design and its implementation for paralleled phase-shifted full-bridge converters (PSFBC) used in distributed power systems. By adopting the digital control strategy, separately used ICs for both PSFBC and LS control functions in the analog system can be merged into a cost-effective digital

  17. An improved zero-voltage and zero-current-switching PWM full-bridge DC-DC converter

    Microsoft Academic Search

    A. Jangwanitlert; K. J. Olejniczak; J. C. Balda

    2003-01-01

    An improved isolated zero-voltage and zero-current switching full-bridge pulse width modulation (ZVZCS-FB-PWM) DC-DC converter having dual voltage outputs of 42 V and 5 V are presented. The leading leg achieves zero voltage switching, and the lagging leg with a series diode and active snubber circuit achieves zero current switching. A phase-shifted (PS) PWM technique is used to obtain ZVZCS by

  18. A digital pulse-width modulator for phase-shift operation of full-bridge isolated DC-DC converters

    Microsoft Academic Search

    L. Corradini; D. Maksimovic

    2010-01-01

    This paper presents the concept, implementation and testing of a digital pulse-width modulator for phase-shift driving of full-bridge isolated DC-DC converters. The proposed phase-shift digital modulator employs a hybrid counter\\/delay line structure in order to achieve a 1.25 ns phase-shift resolution with a switching frequency of about 400 kHz on the secondary side, using a clock frequency of 25 MHz.

  19. A ZVZCS Full-Bridge DC\\/DC Converter with a Passive Auxiliary Circuit in the Primary Side

    Microsoft Academic Search

    Wuhua Li; Yanqun Shen; Yan Deng; Xiangning He

    2006-01-01

    A ZVZCS full-bridge converter with phase-shift control is proposed in this paper. The ZCS condition of the lagging-leg is achieved by using a simple auxiliary circuit, which resets the primary-side current during the freewheeling stage. The ZVZCS operation can reduce the switching losses and the circulating conduction losses. The auxiliary circuit is composed of only a small transformer and two

  20. Bidirectional DC-DC Converter with Full-bridge \\/ Push-pull circuit for Automobile Electric Power Systems

    Microsoft Academic Search

    Koji Yamamoto; Eiji Hiraki; Toshihiko Tanaka; Mutsuo Nakaoka; Tomokazu Mishima

    2006-01-01

    In recent years, energy storage systems assisted by super capacitor have been widely researched and developed to progress power systems for the electronic vehicles. In this paper, a full-bridge\\/push-pull circuit-based bidirectional DC-DC converter and its control methods are proposed. From the results of detailed experimental demonstration, the proposed system is able to perform adequate charge and discharge operation between low-voltage

  1. A soft-switched constant-frequency square-wave half-bridge DC-DC converter

    Microsoft Academic Search

    Charles R. Sullivan; Seth R. Sanders

    1993-01-01

    A constant-frequency zero-voltage-switched square-wave DC-DC converter is introduced, and results from experimental half-bridge implementations are presented. A saturable magnetic element produces the advantageous square waveforms and provides isolated terminals from which the output voltage can be controlled. Semiconductor stresses and losses are minimized both by the square waveforms and by low switching losses. The active switches and the output rectifiers

  2. Flyback Converter Surface Minimization: Design Procedure and Formulas

    E-print Network

    Paris-Sud XI, Université de

    explained in [1-2]. However, the proposed method does not rely on complex computer aided methods, as expert) with following requirements (for auxiliary feeding in railway applications): - PCB size [mm*mm*mm] : 100 * 160

  3. Method of controlling switching of a multiphase inductor-converter bridge

    DOEpatents

    Kustom, Robert L. (Palos Heights, IL); Fuja, Raymond E. (Justice, IL)

    1981-01-01

    In an inductor-convertor circuit for transferring electrical energy between a storage coil and a load coil using a storage thyristor bridge, a load thyristor bridge, and a set of commutating capacitors, operation is improved by a method of changing the rate of delivery of energy in a given direction. The change in rate corresponds to a predetermined change in phase angle between the load bridge and the storage bridge and comprises changing the phase of the bridge by two steps, each equal to half the predetermined change and occurring 180.degree. apart. The method assures commutation and minimizes imbalances that lead otherwise to overvoltages.

  4. A Novel High-Frequency Transformer-Linked Soft-Switching Half-Bridge DC–DC Converter With Constant-Frequency Asymmetrical PWM Scheme

    Microsoft Academic Search

    Tomokazu Mishima; Mutsuo Nakaoka

    2009-01-01

    This paper presents a novel soft-switching half-bridge dc-dc converter with high-frequency link. The newly proposed soft-switching dc-dc converter consists of a single-ended half-bridge inverter controlled by an asymmetrical pulsewidth-modulation scheme and a center-tapped diode rectifier. In order to attain the wide range of soft commutation under constant switching frequency, the single active edge-resonant snubber cell composed of a lossless inductor

  5. A New Soft-Switching PWM Half-Bridge DC-DC Converter with High and Low Side DC Rail Active Edge Resonant Snubbers

    Microsoft Academic Search

    Khairy Fathy; Keiki Morimoto; Toshimitsu Doi; Kang Hoon Koh; Hyun Woo Lee; Mutsuo Nakaoka

    2006-01-01

    This paper presents a new circuit topology of dc bus line switch-assisted half-bridge soft switching PWM inverter type dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency PWM inverter with a high frequency transformer link in addition to dc bus line side power semiconductor switching devices for PWM control scheme and

  6. A Divided Voltage Half-Bridge High Frequency Soft-Switching PWM DC-DC Converter with High and Low Side DC Rail Active Edge Resonant Snubbers

    Microsoft Academic Search

    Khairy Fathy; Keiki Morimoto; Toshimitsu Doi; Hiroyuki Ogiwara; Hyun Woo Lee; Mutsuo Nakaoka

    2006-01-01

    This paper presents a new circuit topology of dc bus line switch-assisted half-bridge soft switching PWM inverter type dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency PWM inverter with a high frequency transformer link in addition to dc bus line side power semiconductor switching devices for PWM control scheme and

  7. A New Soft-Switching PWM High Frequency Half-Bridge Inverter Linked DC-DC Converter with Diode-Clamped Active Edge Resonant Snubbers

    Microsoft Academic Search

    H. Sugimura; T. Etoh; T. Doi; K. Morimoto; B. Saha; S. P. Mun; E. Hiraki; M. Nakaoka

    2008-01-01

    In this paper, the novel circuit topology of half-bridge soft switching PWM DC-DC power converter with a high frequency planar transformer link was presented. The operating principle and switching pattern of the half-bridge soft switching PWM DC-DC power converter described for 40 kHz, 36 V and 400 A output were illustrated and discussed for low voltage and large current output

  8. Advanced High Power DC-DC Converter using Novel Type Half-Bridge Soft Switching PWM Inverter with High Frequency Transformer for Arc Welder

    Microsoft Academic Search

    Keiki Morimoto; Toshimitsu Doi; N. A. Ahmed; Hyun-Woo Lee

    2005-01-01

    This paper presents a new circuit topology of DC bus line switch-assisted half-bridge soft switching PWM inverter type DC-DC converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency PWM inverter with a high frequency transformer link in addition to DC bus line side power semiconductor switching devices for PWM control scheme and

  9. Operation principles of bi-directional full-bridge DC\\/DC converter with unified soft-switching scheme and soft-starting capability

    Microsoft Academic Search

    Kunrong Wang; Fred C. Lee; Jason Lai

    2000-01-01

    A new bi-directional dual full-bridge DC\\/DC converter with a unified soft-switching scheme and soft-start capability is proposed in this paper. A simple voltage clamp branch is used to limit transient voltage across the current-fed bridge and realize zero-voltage-switching (ZVS) in boost mode operation, while achieving hybrid zero-voltage\\/zero-current switching (ZVZCS) for the voltage-fed bridge in buck mode operation. The theory of

  10. Design and control of the phase shift full bridge converter for the on-board battery charger of the electric forklift

    Microsoft Academic Search

    Tae-Hoon Kim; Seung-Jun Lee; Woojin Choi

    2011-01-01

    This paper describes the design and control of phase shift full bridge converter with a current doubler, which can be used for the on-board charger for the lead- acid battery of the electric forklift. Unlike the common resistance load the battery has a large capacitance element and it absorbs the entire converter output ripple current thereby shortening the battery life

  11. New auxiliary active lossless snubber-assisted full bridge soft switching PWM high frequency inverter-fed DC-DC power converter

    Microsoft Academic Search

    T. Etoh; T. Ahmed; E. Hiraki; K. Morimoto; N. A. Ahmed; Ki-Young Suh; Hyun Woo Lee; M. Nakaoka

    2005-01-01

    This paper deals with a novel full bridge circuit topology of high frequency transformer isolated soft switching PWM inverter type DC\\/DC power converter. The zero voltage soft switching PWM DC\\/DC power converter employing an input DC rail series switch and parallel capacitor assisted by high frequency transformer parasitic component is proposed and developed for high performance TIG and MIG arc

  12. Bridges

    NSDL National Science Digital Library

    Leske, Cavin.

    Bridges have been drawing plenty of attention lately, with numerous construction projects around the world and the controversy over the deteriorating bridge infrastructure in the US. They have been an essential part of transportation for hundreds of years, and it is the job of civil engineers to design the safest, most durable bridges possible.Bridge Basics (1) has a large list of different types of bridges with brief explanations. This is a good place for beginners to learn about various bridge designs and parts. The Web site of a nationwide engineering design contest (2) offers free West Point Bridge Designer software. This educational tool allows the user to create a custom virtual bridge model. Although this year's contest is over, another one is planned for next year. Rice University is the home of the Bridges Project (3), a comprehensive database of "all 74 1,000 ft. span bridges in the United States." For each of these, a short description and construction history are given, and some include photos and other interesting facts. The Gibraltar Bridge, a proposed nine mile bridge that connects Europe and Africa, was recently featured on the Discovery Channel's Engineering the Impossible (4). This Web site discusses its specifications, as well as the many challenges that must be overcome for it to be a reality. The Innovative Bridge Research and Construction Program (5) investigates new technologies that can be used in the "repair, rehabilitation, replacement and new construction of bridges" in the US. This is particularly important now, since a large portion of the countries bridges are badly in need of maintenance. A more specific area of research being conducted to protect bridge infrastructure involves the corrosion of steel reinforcements in concrete bridges (6). The material on this site provides an in-depth report on the findings of the Turner-Fairbank Highway Research Center. Technical reports and papers are published in the bimonthly Journal of Bridge Engineering (7). It covers almost any topic related to bridges, and is offered free online by the American Society of Civil Engineers. Fun activities for grade school students are given on this page (8). Separated into three levels of difficulty, the projects give students freedom to learn about and design any kind of bridge structure that interests them. A list of materials and criteria are given, but there are few explicit instructions, allowing for maximum creativity.

  13. Research on voltage sharing for input-series-output-series phase-shift full-bridge converters with common-duty-ratio

    Microsoft Academic Search

    Qiwei Lu; Zijing Yang; Shuai Lin; Suke Wang; Cong Wang

    2011-01-01

    Aiming at the application requirement of high-input-high-output voltage, a novel solution on the base of input-series-output-series (ISOS) connected converter was proposed in the paper. The ISOS converter consists of two zero-voltage-zero-current-switched full bridge (ZVZCS-FB) converters, which are using the common-duty-ratio and share the same controller. The characteristics of the voltage sharing is analyzed in detail and verified by the experiments.

  14. Small-signal and transient analysis of a full-bridge, zero-current-switched PWM converter using an average model

    Microsoft Academic Search

    Chris Iannello; Shiguo Luo; Issa Batarseh

    2003-01-01

    This paper presents a detailed small-signal and transient analysis of a full bridge zero-current-switched (FB-ZCS) PWM converter designed for high voltage, high power applications using an average model. The development shows the model follows directly from the converter's steady-state analysis and is produced by inspection of the converter's instantaneous waveforms. The method used in model development can be extended to

  15. Comparative analysis of ANN and SSM controllers in a ZVCS-Full Bridge Series-Parallel Resonant DC-DC converter

    Microsoft Academic Search

    Zahra Malekjamshidi; Mohammad Jafari

    2011-01-01

    In this paper, two methods of control for high-voltage Full Bridge Series-Parallel Resonant (FBSPR) DC-DC converter are proposed and the results are compared. Soft switching operation using Zero Current Switching (ZCS) and Zero Voltage Switching (ZVS) technologies is employed to decrease the losses and optimize the efficiency of converter. The way of obtaining small-signal model of FBSPR converter using the

  16. Small signal analysis and implementation of phase-shifted full-bridge PWM DC\\/DC converters with current doubler rectifier

    Microsoft Academic Search

    Yong Xie; Yu Fang

    2011-01-01

    This paper presents a small signal model for phase-shifted full-bridge (PSFB) PWM converters with a current doubler rectifier (CDR), which has the same topological structure as the model for PSFB PWM converters with a full-wave rectifier(FWR), but filter inductors and transformer ratios are changed. Based on the new model, small signal transfer functions of PSFB PWM converters with a CDR

  17. Reusable, flyback liquid rocket booster for the Space Shuttle

    Microsoft Academic Search

    Mark G. Benton

    1989-01-01

    This paper outlines a preliminary design for an unmanned, reusable, flyback liquid rocket booster (LRB) as an evolutionary follow-on to the Shuttle solid rocket booster (SRB). Previous Shuttle liquid-propellant booster concepts are reviewed in order to gain insight into these designs. The operating costs, environmental impacts, and abort options of the SRB are discussed. The LRB flight profile and advantages

  18. Bridges

    NSDL National Science Digital Library

    2014-09-18

    Through a five-lesson series that includes numerous hands-on activities, students are introduced to the importance and pervasiveness of bridges for connecting people to resources, places and other people, with references to many historical and current-day examples. In learning about bridge types—arch, beam, truss and suspension—students explore the effect of tensile and compressive forces. Students investigate the calculations that go into designing bridges; they learn about loads and cross-sectional areas by designing and testing the strength of model piers. Geology and soils are explored as they discover the importance of foundations, bearing pressure and settlement considerations in the creation of dependable bridges and structures. Students learn about brittle and ductile material properties. Students also learn about the many cost factors that comprise the economic considerations of bridge building. Bridges are unique challenges that take advantage of the creative nature of engineering.

  19. Modeling and control of a dual-input isolated full-bridge boost converter

    Microsoft Academic Search

    Zhe Zhang; Ole C. Thomsen; Michael A. E. Andersen

    2012-01-01

    In this paper, a steady-state model, a large-signal (LS) model and an ac small-signal (SS) model for a recently proposed dual-input transformer-isolated boost converter are derived respectively by the switching flow-graph (SFG) nonlinear modeling technique. Based upon the converter's model, the controllers are then designed regarding to power stage parameters and system dynamic requirements. The entire system energy management has

  20. Performance evaluation on a fixed-frequency ZCS-PWM asymmetrical half-bridge DC-DC converter with auxiliary Active Edge-Resonant Snubber

    Microsoft Academic Search

    Tomokazu Mishima; Mutsuo Nakaoka

    2008-01-01

    A novel zero current soft-switching (ZCS)-PWM cell-assisted asymmetrical half-bridge (AHB) DC-DC converter topology with a high frequency (HF) link is proposed in this paper. The newly-proposed DC-DC converter consists of a PWM-controlled single-ended half-bridge HF inverter and a center-tapped rectifier linked with a HF transformer. In order to attain the wide range of ZCS commutation in the primary-side HF inverter,

  1. Analysis and control of isolated current-fed full bridge converter in fuel cell system

    Microsoft Academic Search

    Xin KONG; LIM Thian Choi; Ashwin M. KHAMBADKONE

    2004-01-01

    Fuel cells are considered as one of the most prominent sources of green energy in future. However, the potential efficiency of fuel cell will be untapped unless an efficient method can be used to convert the fuel cell low voltage to high voltage grid or user load. Many topologies have been proposed for such applications. However, most of them consider

  2. Design procedure and modeling of high power, high performance, zero-voltage zero-current switched, full-bridge PWM converter

    Microsoft Academic Search

    C. Cuadros; C. Y. Lin; D. Boyevich; R. Watson; G. Skutt; F. C. Lee; P. Ribardiere

    1997-01-01

    A general design procedure for the high power, high performance, zero-voltage zero-current switched full-bridge (ZVZCS-FB), PWM power converter is presented. Average and small-signal models of the power converter are developed. The former shows a decrease in loss of duty-cycle with increasing output power, whereas the latter reveals negative damping effects. Both effects are produced by the interaction between blocking capacitor

  3. Analysis of conducted EMI emissions on a soft-switched full bridge dc-dc converter with a fixed switching frequency

    Microsoft Academic Search

    A. Jangwanitlert; J. C. Balda; K. J. Olejniczak

    2003-01-01

    This paper presents a comparative study between a soft-switched full bridge DC-DC converter using phase-shifted pulse-width-modulation (PSFB-PWM) and another one with PWM control without phase-shifted strategy. The converter using phase-shifted control achieves zero-voltage and zero-current switching (ZVZCS), whereas the other without using phase-shifted control achieves ZVS. The paper describes the operating characteristics and analyzes the performance of both circuits, includes

  4. A novel full-bridge zero-voltage-transition PWM DC\\/DC converter with zero-voltage\\/zero-current switching of the auxiliary switches

    Microsoft Academic Search

    Dong-Yun Lee; Byoung-Kuk Lee; Dong-Seok Hyun

    1998-01-01

    In this paper, a novel full-bridge (FB) zero-voltage-transition (ZVT) PWM DC\\/DC converter topology is proposed. The proposed FB-ZVT PWM DC\\/DC converter has ZVS of main switches for wide load and line ranges and an advantage of achieving zero voltage and zero current switching of the auxiliary switches using the auxiliary network. The auxiliary network is simply composed of saturable inductor,

  5. An improved full-bridge zero-voltage-transition PWM DC\\/DC converter with zero-voltage\\/zero-current switching of the auxiliary switches

    Microsoft Academic Search

    Dong-Yun Lee; Byoung-Kuk Lee; Sang-Bong Yoo; Dong-Seok Hyun

    2000-01-01

    In this paper, a novel full-bridge (FB) zero-voltage-transition (ZVT) pulsewidth modulation (PWM) DC\\/DC converter topology is proposed. The proposed FB-ZVT PWM DC\\/DC converter has zero-voltage switching (ZVS) of main switches for the entire line and load range and an advantage of achieving ZVS and zero-current switching of the auxiliary switches using the auxiliary network. The auxiliary network is simply composed

  6. An improved full-bridge zero-voltage-transition PWM DC\\/DC converter with zero-voltage\\/zero-current switching of the auxiliary switches

    Microsoft Academic Search

    Dong-Yun Lee; Byoung-Kuk Lee; Dong-Seok Hyun

    1998-01-01

    In this paper, an improved full-bridge (FB) zero-voltage-transition (ZVT) PWM DC\\/DC power converter topology is proposed. The proposed FB-ZVT PWM DC\\/DC power converter has the advantage of achieving zero voltage and zero current switching of the auxiliary switches using an auxiliary network. The auxiliary network is simply composed of a saturable inductor, auxiliary capacitors and auxiliary diodes. With the help

  7. Design, implementation, and experimental results of bi-directional full-bridge DC\\/DC converter with unified soft-switching scheme and soft-starting capability

    Microsoft Academic Search

    Kunrong Wang; Lizhi Zhu; Dayu Qu; Hardus Odendaal; Jason Lai; Fred C. Lee

    2000-01-01

    The PWM control, design and implementation issues of the bi-directional dual full-bridge DC\\/DC converter with a unified soft-switching scheme and soft-start capability, which was proposed in a companion paper, are presented in this part of the two-paper sequel. Test results on a 5 kW prototype converter, which is connected between a 12 V battery and a high voltage bus, and

  8. Liquid flyback booster pre-phase: A study assessment

    NASA Astrophysics Data System (ADS)

    Peterson, W.; Ankney, W.; Bell, J.; Berning, M.; Bryant, L.; Bufkin, A.; Cain, L.; Caram, J.; Cockrell, B.; Curry, D.

    1994-09-01

    The concept of a flyback booster has been around since early in the shuttle program. The original two-stage shuttle concepts used a manned flyback booster. These boosters were eliminated from the program for funding and size reasons. The current shuttle uses two Redesigned Solid Rocket Motors (RSRM's), which are recovered and refurbished after each flight; this is one of the major cost factors of the program. Replacement options have been studied over the past ten years. The conclusion reached by the most recent study is that the liquid flyback booster (LFBB) is the only competitive option from a life-cycle cost perspective. The purpose of this study was to assess the feasibility and practicality of LFBB's. The study provides an expansion of the recommendations made during the aforementioned study. The primary benefits are the potential for enhanced reusability and a reduction of recurring costs. The potential savings in vehicle turnaround could offset the up-front costs. Development of LFBB's requires a commitment to the shuttle program for 20 to 30 years. LFBB's also offer enhanced safety and abort capabilities. Currently, any failure of an RSRM can be considered catastrophic, since there are no intact abort capabilities during the burn of the RSRM's. The performance goal of the LFBB's was to lift a fully loaded orbiter under optimal conditions, so as not to be the limiting factor of the performance capability of the shuttle. In addition, a final benefit is the availability of growth paths for applications other than shuttle.

  9. Dual Liquid Flyback Booster for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Blum, C.; Jones, P.; Meinders, B.

    1998-01-01

    Liquid Flyback Boosters provide an opportunity to improve shuttle safety, increase performance, and reduce operating costs. The objective of the LFBB study is to establish the viability of a LFBB configuration to integrate into the shuffle vehicle and meet the goals of the Space Shuttle upgrades program. The design of a technically viable LFBB must integrate into the shuffle vehicle with acceptable impacts to the vehicle elements, i.e. orbiter and external tank and the shuttle operations infrastructure. The LFBB must also be capable of autonomous return to the launch site. The smooth integration of the LFBB into the space shuttle vehicle and the ability of the LFBB to fly back to the launch site are not mutually compatible capabilities. LFBB wing configurations optimized for ascent must also provide flight quality during the powered return back to the launch site. This paper will focus on the core booster design and ascent performance. A companion paper 'Conceptual Design for a Space Shuttle Liquid Flyback Booster' will focus on the flyback system design and performance. The LFBB study developed design and aerodynamic data to demonstrate the viability of a dual booster configuration to meet the shuttle upgrade goals, i.e. enhanced safety, improved performance and reduced operations costs.

  10. A Soft-Switched Full-Bridge Single-Stage AC-to-DC Converter With Low-Line-Current Harmonic Distortion

    Microsoft Academic Search

    A. K. S. Bhat; R. Venkatraman

    2005-01-01

    A single-phase high-frequency transformer-isolated soft-switching single-stage ac-to-dc converter with low-line-current distortion is presented. The circuit configuration is obtained by integrating two discontinuous current mode (DCM) boost converters with a DCM full-bridge buck converter. The zero-voltage switching for the top switches is achieved automatically, whereas bottom switches are aided by zero-voltage transition circuits. The output voltage is regulated by duty-cycle control

  11. Analysis, optimized design and adaptive control of a ZCS full-bridge converter without voltage over-stress on the switches

    Microsoft Academic Search

    Xin Zhang; Henry Shu-hung Chung; Xinbo Ruan; Adrian Ioinovici

    2010-01-01

    This paper presents the analysis and design of a new current-driven soft-switched full-bridge converter, in which all main switches are zero-current-switched (ZCS), and the switches in a switched-capacitor snubber are zero-voltage-switched (ZVS). For each value of the supply and load, the snubber capacitor is adaptively charged at the minimum necessary value for assuring soft-switching; thus, less resonant energy is circulated.

  12. Modeling and Analysis of a Current-Fed ZCS Full-Bridge DC\\/DC Converter with Adaptive Soft-Switching Energy

    Microsoft Academic Search

    H. Wang; H. S. H. Chung; S. Tapuchi; A. Ioinovici

    2009-01-01

    A full dc and ac analysis of a previous proposed boost-type-input soft-switching full-bridge converter is presented. The primary-side switches turn-on\\/off under a zero-current condition (ZCS). The soft-switching is realized by using a simple snubber, formed by two uni-directional switches and a resonant capacitor, in the primary side. The snubber's switches commute under a zero-voltage condition. The resonant energy used for

  13. Small signal analysis and control design of current-fed full-bridge isolated dc\\/dc converter with active-clamp

    Microsoft Academic Search

    UR Prasanna; Akshay K. Rathore

    2012-01-01

    This paper presents a systematic derivation of small signal model of current-fed isolated full-bridge dc\\/dc converter with an active clamp. Active-clamp is an active snubber helps to absorb turn off voltage spike across the power semiconductor devices, thus limiting or clamping the voltage across the devices. Inherently, it results in zero-voltage-switching (ZVS) of all devices (main and auxiliary) resulting in

  14. Practical development of half-bridge high frequency PWM inverter-linked DC-DC converter with diode-clamped active edge resonant cells and extended topologies

    Microsoft Academic Search

    T. Etoh; T. Doi; K. Morimoto; T. Ahmed; H. Sugimura; B. Saha; M. Nakaoka

    2008-01-01

    This paper presents a new circuit prototype of two active edge resonant cells-assisted soft-switching symmetrical PWM half-bridge inverter type DC-DC high power converter employing a high frequency planar transformer with center-tapped secondary windings. Its operating principle is described in detail by using switching mode equivalent circuits which is determined under particular switching pulse pattern scheme, together with its unique features.

  15. A high-frequency 1.5 MVA H-bridge building block for cascaded multilevel converters using emitter turn-off thyrister

    Microsoft Academic Search

    Siriroj Sirisukprasert; Zhenxue Xu; Bin Zhang; Jason Lai; Alex Q. Huang

    2002-01-01

    This paper proposes a 1.5 MVA H-bridge building block (HBBB) using the newly developed emitter turn-off (ETO) thyristor to demonstrate the superior performance of the ETO. The modular HBBB is intended to be used in high-power cascaded multilevel voltage source converters for reactive power compensation applications. Because of theirs identical layouts, the HBBB are easily manufactured for both the building

  16. A novel soft-switching full-bridge DC\\/DC converter: Analysis, design considerations, and experimental results at 1.5 kW, 100 kHz

    Microsoft Academic Search

    Richard Redl; N. O. Sokal; L. Balogh

    1990-01-01

    The authors present an improved soft-switching full-bridge converter which is especially suitable for high-power application (e.g. more than 1 kW output) because of its inherently high efficiency. The addition of an external commutating inductor and two clamp diodes to the phase-shifted PWM (pulse width modulation) full-bridge DC-DC converter substantially reduced the switching losses of the transistors and the rectifier diodes,

  17. Analysis and Design of a Soft-Switching Boost Converter With an HI-Bridge Auxiliary Resonant Circuit

    Microsoft Academic Search

    Sang-Hoon Park; So-Ri Park; Jae-Sung Yu; Yong-Chae Jung; Chung-Yuen Won

    2010-01-01

    A new soft-switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn on and off, and this causes a reduction in the whole system's efficiency. The proposed boost converter utilizes a soft-switching method using an auxiliary circuit with a resonant inductor and capacitor, auxiliary switch, and diodes. Therefore, the proposed soft-switching boost converter

  18. Analysis and Modeling of the ZVZCS Full Bridge PWM DC-DC Converter Using a Secondary Auxiliary Circuit

    Microsoft Academic Search

    Yang Xiaobo; Wu Weiyang; Shen Hong

    2005-01-01

    In this paper a novel ZVZCS FB-PWM DC\\/DC converter is analyzed. Comparing with the small signal models of the buck converter and the ZVS-FB PWM converter, the paper indicates that the characters of ZVZCS small signal model are significantly different from the latter. On the basis of small signal modeling, the compensation network is designed and verified by the simulation

  19. Design considerations for high-voltage high-power full-bridge zero-voltage-switched PWM converter

    Microsoft Academic Search

    J. A. Sabate; V. Vlatkovic; R. B. Ridley; F. C. Lee; B. H. Cho

    1990-01-01

    A steady-state analysis is presented with complete characterization of the converter operation. A small-signal model of the converter is established. The design procedures based on the analysis are presented and the various losses in the circuit assessed. Critical design considerations for a high-power, high-voltage application are analyzed. The results of the analysis are verified using a high-voltage. 2 kW prototype

  20. Advanced High Power DC-DC Converter using A Novel Type Voltage Source Full-Bridge Soft-Switching PWM Inverter with High Frequency Transformer Link for Arc Welding Applications

    Microsoft Academic Search

    Keiki Morimoto; Toshimitsu Doi; Haruhiko Manabe; Tarek Ahmed; Eiji Hiraki; Hyun-Woo Lee; Mutsuo Nakaoka

    2006-01-01

    This paper presents a new circuit topology of full-bridge soft-switching PWM inverter linked DC-DC power converter composed of conventional full-bridge high frequency PWM inverter with high frequency transformer and an active quasi-resonant snubber consisting of an additional power switching device in series with DC busline and a lossless capacitor in parallel with DC busline. Under this proposed high frequency soft-switching

  1. Next generation high efficiency high power dc-dc converter incorporating active switch and snubbing capacitor assisted full-bridge soft-switching PWM inverter with high frequency transformer for large current output

    Microsoft Academic Search

    Keiki Morimoto; T. Doi; H. Manabe; M. Nakaoka; Hyun-Woo Lee; Nabil A. Ahmed; E. Hiraki; T. Ahmed

    2005-01-01

    This paper presents a new circuit topology of dc busline switch-assisted full-bridge soft-switching PWM inverter type dc-dc power converter which is composed of typical voltage source H full-bridge type high frequency PWM inverter in addition to a single dc busline side power semiconductor switching device for PWM scheme and a capacitive lossless snubber. Under the newly-proposed high frequency inverter link

  2. A Novel Soft-Switching PWM Full-Bridge DC\\/DC Converter with DC Busline Series Switch-Parallel Capacitor Edge Resonant Snubber Assisted by High-Frequency Transformer Leakage Inductor

    Microsoft Academic Search

    Khairy Fathy; T. Doi; K. Morimoto; Hyun Woo Lee; M. Nakaoka

    2006-01-01

    This paper presents two new circuit topologies of DC busline side active edge resonant snubber assisted soft-switching PWM high frequency AC link full-bridge DC-DC converter acceptable for 200V-rms and 400V-rms utility AC mains. All the power switches in the full-bridge arms and DC busline can turns on with ZCS turn-on and turn-off with ZVS and the switching power losses of

  3. Digital Bridges: Bridges of the Nineteenth Century

    NSDL National Science Digital Library

    2002-01-01

    The collection consists of thirty representative 19th-century American bridge engineering monographs, manuals, and documents from the Lehigh University Libraries' Special Collections. The source documents have been scanned, converted to text, and partially corrected to make all significant terms and personal and proper names retrievable through the site's search engine. Topics include specific bridges (the Brooklyn Bridge, the East River Bridge), bridge types (suspension bridges, wrought iron bridges), bridge components (cabling, foundations), bridge design, bridge disasters, and others. The collection is browseable by title and searchable by keyword. Printable versions of the documents are also available. A glossary is also provided with definitions of terms, short biographies of authors, and descriptions of some of the bridges

  4. Modeling, Analysis and Design of 15kW Zero-Voltage Zero-Current Switched Full Bridge PWM Converter

    Microsoft Academic Search

    Yimeng Shi; Guozhu Chen; Yulin Li

    2007-01-01

    This paper presents the modeling and design of a novel ZVZC FB-PWM converter. Compared to the traditional topology which employs a saturated inductor to block the reverse current in order to achieve ZCS for the lagging leg, a novel one using two diodes in series with the lagging leg is adopted. Both the duty ratio loss is reduced and the

  5. A novel soft-switching full-bridge DC\\/DC converter: analysis, design considerations, and experimental results at 1.5 kW, 100 kHz

    Microsoft Academic Search

    R. Redl; N. O. Sokal; L. Balogh

    1991-01-01

    The addition of an external commutating inductor and two clamp diodes to the phase-shifted PWM (pulsewidth modulated) full-bridge DC\\/DC converter substantially reduces the switching losses of the transistors and the rectifier diodes, under all loading conditions. The authors give analyses, practical design considerations, and experimental results for a 1.5 kW converter with 60 V, 25 A output, operating at 100

  6. Transient analysis and control of bias magnetic state in the transformer of on-line pulse-width-modulation switching full bridge direct current-direct current converter

    NASA Astrophysics Data System (ADS)

    Chen, Jiaxin; Guo, Youguang; Zhu, Jianguo; Wei Lin, Zhi

    2012-04-01

    This paper presents a finite element analysis (FEA) based method for analyzing and controlling the bias magnetic state of the transformer of a pulse-width-modulation (PWM) switching full bridge dc-dc converter. A field-circuit indirect coupling method for predicting the transient bias magnetic state is introduced first. To increase flexibility of the proposed method, a novel transformer model which can address not only its basic input-output characteristic, but also the nonlinear magnetizing inductance, is proposed. Both the asymmetric characteristic and the variable laws of the current flowing through the two secondary windings during the period of PWM switching-off state are highlighted. Finally, the peak magnetizing current controlled method based on the on-line magnetizing current computation is introduced. Analysis results show that this method can address the magnetic saturation at winding ends, and hence many previous difficulties, such as the start-up process and asymmetry of power electronics, can be easily controlled.

  7. Discrete time domain small-signal modeling of full-bridge phase-shifted series resonant converter

    Microsoft Academic Search

    A. A. Aboushady; K. H. Ahmed; S. J. Finney; B. W. Williams

    2010-01-01

    This paper provides an analytical discrete small-signal state-space model of the phase-shift modulated series resonant converter used to obtain an explicit linearized phase-shift to output voltage transfer function. This transfer function is useful for linear closed loop control design. Initially, the effective duty-ratio to output voltage transfer function is derived. It is then proven, analytically and through results, that it

  8. Two full-bridge input-series-output-parallel integrated-magnetic converter for high input voltage

    Microsoft Academic Search

    Xuejun Mal; Jinhong Niu; Yong Kang

    2005-01-01

    In this paper, a new topology for high input voltage converter with input-series-output-parallel is presented. A key problem of this topology is the input voltage balancing. A voltage error between two inputs capacitor is sensed and controlled. An integrated-magnetic transformer is applied to realize the input voltage sharing. Three closed loops of output voltage, limited load current and input capacitor

  9. An improved high-voltage IGBT-based half-bridge DC\\/DC converter for railway applications

    Microsoft Academic Search

    Dmitri Vinnikov; Juhan Laugis

    2011-01-01

    Purpose – The paper presents the findings of an R&D project connected to the development of 50 kW auxiliary power supply for the high-voltage DC-fed commuter trains. The aim was to introduce a new generation power converter utilizing high-voltage insulated gate bibolar transistor (IGBT) modules, which can outpace the predecessors in terms of efficiency and power density, i.e. to provide

  10. Interleaved power converter

    DOEpatents

    Zhu, Lizhi (Canton, MI)

    2007-11-13

    A power converter architecture interleaves full bridge converters to alleviate thermal management problems in high current applications, and may, for example, double the output power capability while reducing parts count and costs. For example, one phase of a three phase inverter is shared between two transformers, which provide power to a rectifier such as a current doubler rectifier to provide two full bridge DC/DC converters with three rather than four high voltage inverter legs.

  11. Reduction of power converter EMI emission using soft-switching technique

    Microsoft Academic Search

    H. Chung; S. Y. R. Hui; K. K. Tse

    1998-01-01

    Measurements of conducted and radiated electromagnetic interference (EMI) emission from hard-switched and soft-switched buck, boost, and flyback converters of similar power ratings are presented. Results indicate that EMI emission can be substantially reduced by using a soft-switching technique in power converters. Thus, the soft-switching technique provides a practical and useful solution to reduce EMI emission from switched-mode power circuits. A

  12. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng (Jason) [Future Energy Electronics Center, Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA (United States)

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  13. Advanced High Power DC-DC Converter using A Novel Type Voltage Source Full-Bridge Soft-Switching PWM Inverter with High Frequency Transformer Link for Arc Welding Applications

    NASA Astrophysics Data System (ADS)

    Morimoto, Keiki; Doi, Toshimitsu; Manabe, Haruhiko; Ahmed, Tarek; Hiraki, Eiji; Lee, Hyun-Woo; Nakaoka, Mutsuo

    This paper presents a new circuit topology of full-bridge soft-switching PWM inverter linked DC-DC power converter composed of conventional full-bridge high frequency PWM inverter with high frequency transformer and an active quasi-resonant snubber consisting of an additional power switching device in series with DC busline and a lossless capacitor in parallel with DC busline. Under this proposed high frequency soft-switching PWM inverter linked DC-DC converter, four power switches in the full-bridge arms and DC busline series switch can achieve ZVS at turn-off commutation. By developing the advanced soft-switching PWM high frequency inverter type DC-DC converter, although the conduction power loss of DC busline series power switch increases a little, the total turn-off switching loss of full-bridge high frequency inverter power modules can be sufficiently lowered more and more in the higher frequency range of 60kHz. As a result, when the switching frequency of high frequency inverter power stage using IGBT power modules is designed so as to be more than about 10kHz, the more the switching frequency of inverter increases, the more this high frequency soft-switching DC-DC converter has remarkable advantage as for the power conversion efficiency as compared with the conventional hard-switching PWM inverter DC-DC converter. Its practical effectiveness of high power density and high performance is actually proved for TIG arc welding equipment in industry.

  14. A Soft-Switching Utility-Interfaced Power Conditioner with High-Frequency Flyback Transformer Link

    Microsoft Academic Search

    Srawouth Chandhaket; M. Nakaoka

    2005-01-01

    In this paper, we propose a high-frequency switching pulse modulation utility-interfaced power conditioner with the flyback high-frequency transformer link and the switched-capacitor snubber cell. With the aid of the switched-capacitor resonant snubber cell, the high-frequency switching devices in the primary side of the proposed DC-to-AC power inverter can be turned-off with zero voltage soft-switching (ZVS). Moreover, the proposed power conditioner

  15. Power converters and amplifiers (review of \\

    Microsoft Academic Search

    Marian Kazmierkowski

    2009-01-01

    This book is a comprehensive textbook in the areas of electrical, electronics, and telecommunications engineering. It consists of 17 chapters and two appendices. Some of the topics covered include: buck PWM DC-DC converters; boost PWM DC-DC converters; buck-boost-PWM DC-DC converters; half-bridge and full-bridge converters; push-pull PWM DC-DC converters; open-loop small-signal characteristics of boost converters for CCM; current-mode control of boost

  16. Boost Converter Animation

    NSDL National Science Digital Library

    This animation, created by faculty at Dartmouth University, is a boost converter. The resource features other animations such as buck and discontinuous converters. They also add simple diode, bridge and half-wave rectifiers. Although simple in design, this can still be a useful resource for those interested in electrical engineering.

  17. Discontinuous Buck Converter

    NSDL National Science Digital Library

    This animation, created by faculty at Dartmouth University, is a discontinuous buck converter. The resource features other animations such as boost and discontinuous converters. They also add simple diode, bridge and half-wave rectifiers. Although simple in design, this can still be a useful resource for those interested in electrical engineering.

  18. Frequency response of resonant converters

    Microsoft Academic Search

    K. Siri; C. Q. Lee; S. J. Fang

    1990-01-01

    The general theory of the discrete small-signal analyses of resonant converters has been formulated in a closed form. For simplicity and verification, the state-plane diagram technique is used for the analysis. This theory is applicable to converters in half-bridge or full-bridge configurations when operated in the continuous conduction mode. Using a series resonant converter (SRC) as an example, the analytic

  19. High-frequency flyback transformer linked utility-connected sinewave soft-switching power conditioner using a switched capacitor snubber

    Microsoft Academic Search

    S. Chandhaket; K. Ogura; M. Nakaoka; Y. Konishi

    2004-01-01

    In this paper, the high-frequency switching pulse modulation utility-interfaced power conditioner with a flyback high-frequency transformer link has been proposed. With the aid of the switched-capacitor resonant snubber cell, the high-frequency switching devices in the primary side of the proposed DC-to-AC power inverter can be turned-off with zero voltage soft-switching (ZVS). Moreover, the proposed power conditioner operates the currents in

  20. Analysis of capacitor-related mid-voltage point shift problems in high-voltage half-bridge DC\\/DC converters

    Microsoft Academic Search

    I. Roasto; D. Vinnikov; T. Lehtla

    2008-01-01

    Half-bridge topology is an attractive topology for many power electronics applications. It is simple and more cost-effective than other topologies. The new high-voltage IGBTs on the market enlarge the possibilities and add to the attractiveness of that topology, in particular in high voltage applications. However, despite the overall design simplicity, the designer must guard against a number of problems with

  1. A No DC-Gain Error Small-Signal Model for the Zero-Voltage-Switching Phase-Shift-Modulated Full-Bridge DC-DC Converter

    Microsoft Academic Search

    Cleber Zanatta; José Renes Pinheiro

    2006-01-01

    In this paper, an improved small-signal model for the zero-voltage-switching phase-shift-modulated full-bridge which eliminates the DC-gain errors of its line-to-output and control-to-output model transfer functions is presented. A DC-gain and a frequency response comparison among small-signal models are evaluated. The model presented here demonstrates to be accurate for different designs parameters, being it in a simple s-domain polynomial ratio form.

  2. Modeling, analysis and design of 10 kW parallel module zero-voltage zero-current switched full bridge PWM converter

    Microsoft Academic Search

    Hangseok Choi; J. W. Kim; J. H. Lee; B. H. Cho

    2000-01-01

    In this paper, the modeling and the design of the 10 kW parallel module converter are presented. Due to the high input voltage and power level, IGBTs are selected for the switching devices. The ZVZCS techniques enable the ZVZCS FB-PWM topology to operate at the switching frequency of 40 kHz, while maintaining an efficiency of over 94% at full load.

  3. Common-Duty-Ratio Control of Input-Series Output-Parallel Connected Phase-shift Full-Bridge DC–DC Converter Modules

    Microsoft Academic Search

    Jianjiang Shi; Jie Luo; Xiangning He

    2011-01-01

    Input-series output-parallel (ISOP)-connected con- verters allow the use of low-voltage and low-power converter mod- ules for high input-voltage and high-power applications. Further, the use of high-frequency, low-voltage MOSFETs, which are opti- mized for very low on-resistance, is enabled, resulting in lower con- duction losses and higher power density. In this paper, a common- duty-ratio control scheme is proposed for an

  4. Development of Electrolytic-Capacitor-Less Ultra-Thin Flyback Converter Shintaro Takagi*, Toshihiko Noguchi (Nagaoka University of Technology),

    E-print Network

    Fujimoto, Hiroshi

    Pout C1 (6) 1 )( 2 1 22 max1 on thc t VVCP -= (4) cout PP (5) 2 22 max 1 th onout VV tP C - (6) 22.6 1 D1, D2 CMF01 0.98 2 Th1 USF5G49 2.6 1 C1 THC 200 V, 2.2 F 3.0 20 Q1 2SK3438 3.0 1 T1 PC95 5.5 1 C2 THC 50V, 22 F 3.0 20 #12;56 3 (20 V ) 5 mm 5.5 mm C1 THC 200 V 2.2 F 20 44 F

  5. Bridge permeameter

    DOEpatents

    Graf, Darin C. (Edgewood, NM); Warpinski, Norman R. (Albuquerque, NM)

    1996-01-01

    A system for single-phase, steady-state permeability measurements of porous rock utilizes a fluid bridge arrangement analogous to a Wheatstone bridge. The arms of the bridge contain the sample and calibrated flow resistors.

  6. Modular DC-DC converter system for energy harvesting with EAPs

    NASA Astrophysics Data System (ADS)

    Eitzen, L.; Graf, C.; Maas, J.

    2013-04-01

    Energy harvesting with EAPs requires an energy-efficient power electronics providing a bidirectional energy transfer and operating voltages of up to several kilovolts. A possibility to achieve a high energy-efficiency for high voltage conversion is the use of a modular converter system consisting of several bidirectional converter modules, which are connected in series on the converter output side and in parallel at the input side. Since each converter stage provides only a part of the overall converter output voltage, the converter module output voltages can effectively be reduced by choosing the number of cascaded converter modules appropriately. This allows the use of standard semiconductor switches with superior electrical characteristics compared to high voltage semiconductors, enabling a high energy-efficiency and smaller passive components. Since EAP devices exhibit a mainly capacitive behavior and a limitation of the operating current is required for electrode protection, the utilized converter structure/topology has to be operated as a controllable current source on the lowest control level, which is achieved by operating the converter modules of the modular converter system with a subordinate closed-looped current control scheme. In order to avoid voltage unbalances among the single converter modules, a method for voltage balancing is presented. For validation, experimental results of a realized bidirectional flyback converter prototype are presented and discussed.

  7. Three Bridge Fryer's Ford Bridge, Nimrod Bridge, and Ward's ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Three Bridge - Fryer's Ford Bridge, Nimrod Bridge, and Ward's Crossing Bridge - Fryer's Ford Bridge, Spanning East Fork of Point Remove Creek at Fryer Bridge Road (CR 67), Solgohachia, Conway County, AR

  8. Straw Bridges

    NSDL National Science Digital Library

    2012-03-20

    Learners design, build and test a model bridge out of straws. The bridge must span 25 cm across a gap between two tables or two chairs. To measure the load, the bridge must securely hold a small cup. Learners test the load by placing as many pennies in the cup as possible and counting how many the bridge can hold.

  9. Popsicle Bridge

    NSDL National Science Digital Library

    IEEE

    2013-08-30

    In this activity, learners explore how engineering has impacted the development of bridges over time, including innovative designs and the challenge of creating bridges that become landmarks for a city. Learners work in teams of "engineers" to design and build their own bridge out of glue and popsicle sticks. Learners test their bridges using weights, evaluate their results, and present their findings to the group.

  10. Spaghetti Bridge

    NSDL National Science Digital Library

    COSI

    2009-01-01

    In this engineering activity, learners investigate the differences between the strength of bridges made from flat and round building materials. They construct simple bridges out of linguine, which has a rectangular shape, and spaghetti, which has a circular shape. They then test and compare the weight capacity of the bridges.

  11. Bridge permeameter

    DOEpatents

    Graf, D.C.; Warpinski, N.R.

    1996-08-13

    A system is described for single-phase, steady-state permeability measurements of porous rock which utilizes a fluid bridge arrangement analogous to a Wheatstone bridge. The arms of the bridge contain the sample and calibrated flow resistors. 8 figs.

  12. Spaghetti Bridge

    NSDL National Science Digital Library

    K-12 Outreach Office,

    Civil engineers design structures such as buildings, dams, highways and bridges. Student teams explore the field of engineering by making bridges using spaghetti as their primary building material. Then they test their bridges to see how much weight they can carry before breaking.

  13. Designing Bridges

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program and Laboratory,

    Students learn about the types of possible loads, how to calculate ultimate load combinations, and investigate the different sizes for the beams (girders) and columns (piers) of simple bridge design. Students learn the steps that engineers use to design bridges: understanding the problem, determining the potential bridge loads, calculating the highest possible load, and calculating the amount of material needed to resist the loads.

  14. Synthesis of Multilevel Converters Based on Single-and\\/or Three-phase Converter Building Blocks

    Microsoft Academic Search

    Jun Wen; K. Smedley

    2007-01-01

    This paper synthesizes a family of multilevel converters that is constructed by using multiple well-developed single-phase converters and\\/or three-phase converters as the building blocks. The resulting advantages include modular structure that leads to convenient construction, maintenance and control as well as extension to higher voltage levels. One successful example from this family is the cascaded H-bridge converter, which is now

  15. Matrix converters

    Microsoft Academic Search

    P. W. Wheeler; J. C. Clare; L. Empringham; M. Bland; K. G. Kerris

    2004-01-01

    This paper deals with the vector-controlled MCT matrix converter induction motor drive with minimized commutation time and enchanced waveform quality. It also deals with the design, construction, and testing of a 10-kVA three-phase to three-phase matrix converter induction motor drive. The converter has been built using discrete 65 A metal-oxide-semiconductor (MOS) controlled thyristors (MCTs). The commutation time has been minimized

  16. Integrated high quality rectifier-regulators

    Microsoft Academic Search

    Michael Madigan; Robert Erickson; Esam Ismail

    1992-01-01

    A family of AC-to-DC converters which integrate the functions of low harmonic rectification, low frequency energy storage, and wide bandwidth output voltage control into a single converter containing one, two, or four active switches is presented. These converters utilize a discontinuous conduction mode input inductor, an internal energy storage capacitor, and transformer secondary circuits which resemble the bridge, forward, flyback,

  17. Thermionic converter

    DOEpatents

    Fitzpatrick, G.O.

    1987-05-19

    A thermionic converter is set forth which includes an envelope having an electron collector structure attached adjacent to a wall. An electron emitter structure is positioned adjacent the collector structure and spaced apart from opposite wall. The emitter and collector structures are in a common chamber. The emitter structure is heated substantially only by thermal radiation. Very small interelectrode gaps can be maintained utilizing the thermionic converter whereby increased efficiency results. 10 figs.

  18. Modeling and simulation of DC\\/DC converters based on double-loop control

    Microsoft Academic Search

    Jun Liu; Ping Yang; Xucheng Lin; Shaoxiong Zhou

    2009-01-01

    The closed-loop control circuit of full-bridge DC\\/DC converter for wind power generation is designed in this article. First of all, the small-signal model of full-bridge DC\\/DC converter is established, and then with the help of automatic control theory and Matlab software, the control parameters are set to derive the mathematic model of high-power full-bridge DC\\/DC converters with closed-loop control. In

  19. Influence of converters on the superconducting field-circuit of a three-phase synchronous generator

    Microsoft Academic Search

    H. P. Groeter; H. W. Lorenzen; W. Rehm; R. Schweiger

    1991-01-01

    Experimental investigations of the influence of converter feeding the field circuit of a three-phase synchronous generator with a superconducting field winding have been performed. Four converter circuits have been tested: a B6 three-phase bridge, two parallel B6 three-phase bridges, a three-phase bridge with bypass thyristors, and a high-current power-MOSFET converter. Steady-state and transient operation have been tested. There was a

  20. Synthesis of Multilevel Converters Based on Single and\\/or Three-Phase Converter Building Blocks

    Microsoft Academic Search

    Jun Wen; Keyue Ma Smedley

    2008-01-01

    This paper synthesized a family of multilevel converters that is constructed by using multiple well-developed single- and\\/or three-phase converter building blocks. The resulting advantages include a modular structure that leads to convenient construction and maintenance as well as easy extension to higher voltage levels. One successful example from this family is the cascaded H-bridge converter, which is now widely used

  1. The myosin converter domain modulates muscle performance.

    PubMed

    Swank, Douglas M; Knowles, Aileen F; Suggs, Jennifer A; Sarsoza, Floyd; Lee, Annie; Maughan, David W; Bernstein, Sanford I

    2002-04-01

    Myosin is the molecular motor that powers muscle contraction as a result of conformational changes during its mechanochemical cycle. We demonstrate that the converter, a compact structural domain that differs in sequence between Drosophila melanogaster myosin isoforms, dramatically influences the kinetic properties of myosin and muscle fibres. Transgenic replacement of the converter in the fast indirect flight muscle with the converter from an embryonic muscle slowed muscle kinetics, forcing a compensatory reduction in wing beat frequency to sustain flight. Conversely, replacing the embryonic converter with the flight muscle converter sped up muscle kinetics and increased maximum power twofold, compared to flight muscles expressing the embryonic myosin isoform. The substitutions also dramatically influenced in vitro actin sliding velocity, suggesting that the converter modulates a rate-limiting step preceding cross-bridge detachment. Our integrative analysis demonstrates that isoform-specific differences in the myosin converter allow different muscle types to meet their specific locomotion demands. PMID:11901423

  2. A PSR single-stage flyback LED driver with simple line regulation and quasi-resonant operation

    NASA Astrophysics Data System (ADS)

    Weidong, Nie; Zongguang, Yu; Haibing, Wang; Bin, Guo; Long, Teng; Lihang, Yang

    2014-08-01

    A single-stage flyback driving integrated circuit (IC) for light-emitting diodes (LEDs) is proposed. With an average primary-side current estimation and negative feedback networks, the driver operates in the boundary conduction mode (BCM), while the output current can be derived and regulated precisely. By means of a simple external resistor divider, a compensation voltage is produced on the ISEN pin during the turn-on period of the primary MOSFET to improve the line regulation performance. On the other hand, since the delay time between the time that the secondary diode current reaches zero and the turn-on time of the MOSFET can be automatically adjusted, the MOSFET can always turn on at the valley voltage even if the inductance of the primary winding varies with the output power, resulting in quasi-resonant switching for different primary inductances. The driving IC is fabricated in a Dongbu HiTek's 0.35 ?m bipolar-CMOS-DMOS process. An 18 W LED driver is finally built and tested. Results show that the driver has an average efficiency larger than 86%, a power factor larger than 0.97, and works under the universal input voltage (85-265 V) with the LED current variation within ±0.5%.

  3. Thermionic converter

    DOEpatents

    Fitzpatrick, Gary O. (Livermore, CA)

    1987-05-19

    A thermionic converter (10) is set forth which includes an envelope (12) having an electron collector structure (22) attached adjacent to a wall (16). An electron emitter structure (24) is positioned adjacent the collector structure (22) and spaced apart from opposite wall (14). The emitter (24) and collector (22) structures are in a common chamber (20). The emitter structure (24) is heated substantially only by thermal radiation. Very small interelectrode gaps (28) can be maintained utilizing the thermionic converter (10) whereby increased efficiency results.

  4. High power density dc/dc converter: Selection of converter topology

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; and Three Phase Dual Active Bridges DC/DC Converter (Topology C). The salient features of these topologies are: (1) All are minimal in structure, i.e., each consists of an input and output bridge, input and output filter and a transformer, all components essential for a high power dc/dc conversion process; (2) All devices of both the bridges can operate under near zero-voltage conditions, making possible a reduction of device switching losses and hence, an increase in switching frequency; (3) All circuits operate at a constant frequency, thus simplifying the task of the magnetic and filter elements; (4) Since, the leakage inductance of the transformer is used as the main current transfer element, problems associated with the diode reverse recovery are eliminated. Also, this mode of operation allows easy paralleling of multiple modules for extending the power capacity of the system; (5) All circuits are least sensitive to parasitic impedances, infact the parasitics are efficently utilized; and (6) The soft switching transitions, result in low electromagnetic interference. A detailed analysis of each topology was carried out. Based on the analysis, the various device and component ratings for each topology operating at an optimum point, and under the given specifications, are tabulated and discussed.

  5. Control of a modular multilevel cascade BTB system using bidirectional isolated DC\\/DC converters

    Microsoft Academic Search

    Hirofumi Akagi; Ryohei Kitada

    2010-01-01

    This paper discusses the 6.6-kV BTB (back-to-back) system combining bidirectional isolated dc\\/dc converters with modular multilevel cascade PWM converters. The system consists of multiple converter cells connected in cascade per phase at both front ends. Each converter cell consists of a bidirectional isolated high-frequency dc\\/dc converter and two voltage-source H-bridge PWM converters. Extremely low voltage steps bring a significant reduction

  6. Basswood Bridges

    NSDL National Science Digital Library

    Abramowitz, Harvey

    The Elementary Engineering Design course for freshmen students at Purdue University Calumet consists of two components: one ME and one EE. Due to the two part structure and in order to expose the students to the faculty, it is also team taught. The course counts as two credits, with the format one hour lecture and three hours lab. The basswood bridge is the major project of the ME half and counts for one quarter of the total course grade. The object, as is usual with bridge projects, is to design, build and test a truss bridge having a high strength to weight ratio. The design process includes statics analysis in combination with the tensile and compressive properties of the basswood. The details of the project from initial design to final testing are provided.

  7. Bridged graphite oxide materials

    NASA Technical Reports Server (NTRS)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  8. Bridge Inspector's Training Manual.

    ERIC Educational Resources Information Center

    Federal Highway Administration (DOT), Washington, DC. Bureau of Public Roads.

    A guide for the instruction of bridge inspectors is provided in this manual as well as instructions for conducting and reporting on a bridge inspection. The chapters outline the qualifications necessary to become a bridge inspector. The subject areas covered are: The Bridge Inspector, Bridge Structures, Bridge Inspection Reporting System,…

  9. The Belizean Bridge Activity.

    ERIC Educational Resources Information Center

    Murfin, Brian

    2000-01-01

    Describes the famous swing bridge in Belize. Students build bridges from a variety of materials and answer the questions, What are different types of bridges?, How do bridges work?, How can you tell if a bridge design will be safe?, and What is the best way to build a bridge over a river while still allowing boat traffic? (SAH)

  10. Comparison of topologies suitable for Capacitor Charging Systems

    E-print Network

    Maestri, S; Uicich, G; Benedetti, M; Cravero, JM

    2014-01-01

    This paper presents a comparison between topologies suitable for capacitor charging systems. The topologies under evaluation are a flyback converter, a half-bridge series resonant converter and a full-bridge phase-shifted converter. The main features of these topologies are highlighted, which allows the proper topology selection according to the application requirements. Moreover, the performed analysis permits to characterize the operational range of the main components thus allowing their appropriate sizing and selection. Simulation results are provided.

  11. A novel power converter for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Yuvarajan, S.; Yu, Dachuan; Xu, Shanguang

    A simple and economical power conditioner to convert the power available from solar panels into 60 Hz ac voltage is described. The raw dc voltage from the solar panels is converted to a regulated dc voltage using a boost converter and a large capacitor and the dc output is then converted to 60 Hz ac using a bridge inverter. The ratio between the load current and the short-circuit current of a PV panel at maximum power point is nearly constant for different insolation (light) levels and this property is utilized in designing a simple maximum power point tracking (MPPT) controller. The controller includes a novel arrangement for sensing the short-circuit current without disturbing the operation of the PV panel and implementing MPPT. The switching losses in the inverter are reduced by using snubbers. The results obtained on an experimental converter are presented.

  12. Building Bridges

    NSDL National Science Digital Library

    Roger Day

    2000-01-01

    In this lesson, students build bridges from arithmetical to algebraic thinking by exploring problems that are not limited to single-solution responses. Values organized into tables and graphs are used to move toward symbolic representations. Problem situations at the middle school level involve linear, quadratic, and exponential models. The site is valuable not only for its problems for students but also for the teaching strategy illustrated here.

  13. Matrix converter topologies with reduced number of switches

    Microsoft Academic Search

    Lixiang Wei; T.A. Lipo; Ho Chan

    2002-01-01

    A direct AC-to-AC converter commonly termed a matrix converter has a simple structure and many attractive features. However, the complexity of its conventional PWM strategy is prone to commutation failure, which is a factor that keeps it from being utilized in industry. This paper focuses on several alternative dual-bridge matrix topologies which do not possess this problem. First, these converters

  14. Bridge Builders

    NSDL National Science Digital Library

    2010-01-01

    In this interactive game, students build bridges using fractional lengths in the form of fraction bars. Gap length may be known or unknown, entirely empty or partially filled. Fractions to fill the gap must be constructed in specific ways, using the four basic operations. After five tries at one level, the game resets. Note that the game sometimes expects particular answers: students may need to multiply 2/5 by 3 rather than multiplying 3/5 by 2, for example, even though both computations would produce the same result.

  15. Switching Power Converter A/D Converters

    E-print Network

    Controller Health Monitoring Efficiency Monitoring Frequency Response Monitoring Health Monitoring Sensing Points Figure 1. System architecture for health monitoring test-bed. Converter parameters are sensed then displays processed data concerning the converter health status. Online Health Monitoring in Digitally

  16. Performance analysis of DAB DC-DC converter under zero voltage switching

    Microsoft Academic Search

    R. T. Naayagi; A. J. Forsyth; R. Shuttleworth

    2011-01-01

    This paper investigates the effect of snubber capacitor on the zero voltage switching (ZVS) boundary of the dual active bridge (DAB) DC-DC converter. The analysis is performed to determine the minimum current required during transistor turn- off to achieve successful ZVS and the ZVS boundary operating conditions of the converter are obtained. The operation of the converter during transistor turn-off

  17. Buck Converter Animation

    NSDL National Science Digital Library

    This website from the Thayer School of Engineering at Dartmouth College features an animation of a buck converter. A buck converter is a step-down DC to DC converter. Its design is similar to the step-up boost converter, and like the boost converter it is a switched-mode power supply that uses two switches (a transistor and a diode), an inductor and a capacitor.

  18. Design of photovoltaic high frequency link inverter based on push-pull forward converter

    Microsoft Academic Search

    Shungang Xu

    2010-01-01

    In this paper, a photovoltaic high frequency link inverter is proposed. The inverter is constituted of push-pull forward DC-DC converter and DC-AC inverter full bridge. The push-pull forward converter has some superiority in low voltage high current situation and achieves electrical isolation between the photovoltaic battery and the AC output. The push-pull forward converter is used to convert the photovoltaic

  19. Integrated high-quality rectifier-regulators

    Microsoft Academic Search

    Michael T. Madigan; Robert W. Erickson; Esam Hamid Ismail

    1999-01-01

    A new family of AC-DC converters is derived which integrate the functions of low-harmonic rectification, low-frequency energy storage, and wide-bandwidth output voltage control into a single converter containing one, two, or four active switches. These converters utilize a discontinuous conduction mode input inductor, an internal energy storage capacitor, and transformer secondary circuits which resemble the bridge, forward, flyback, or Cuk

  20. Control and Design of a Modular Multilevel Cascade BTB System Using Bidirectional Isolated DC\\/DC Converters

    Microsoft Academic Search

    Hirofumi Akagi; Ryohei Kitada

    2011-01-01

    This paper discusses the control and design of the 6.6-kV back-to-back (BTB) system combining bidirectional iso- lated dc\\/dc converters and modular multilevel cascade pulsewidth modulation (PWM) converters. The system consists of multiple converter cells connected in cascade per phase at both front ends. Each converter cell consists of a bidirectional isolated medium- frequency dc\\/dc converter and two voltage-source H-bridge (single-

  1. Generalized Average Model of Series Parallel Resonant Converter with Capacitive Output Filter

    E-print Network

    Paris-Sud XI, Université de

    ) Rectifier non conduction angle (rad) R Load resistance () R* Equivalent load resistance () VAB Full bridge with capacitive output filter and equivalent scheme of the converter. VAB hal-00521993,version1-29Sep2010 Author

  2. Design issues for high voltage converters for ion engines

    SciTech Connect

    King, R.J.; Stuart, T.A. [Univ. of Toledo, OH (United States)

    1995-12-31

    A design strategy is presented for a power converter for a high voltage ion engine for a spacecraft application. Various design issues such as appropriate topologies and control methods are considered. In this particular instance it was determined that a full bridge converter with phase shift gating and voltage mode control provided an efficient system with a minimum of electromagnetic interference. This system can be implemented in a straightforward manner, and it is relatively easy to protect from faults at the output.

  3. A ?? based DC-DC converter with supply noise suppression

    Microsoft Academic Search

    Kyle Schulmeyer; Chintan Trehan; Kwong S. Chao

    2007-01-01

    An architecture that reduces the effects of supply noise on the regulated output of a DC-DC converter has been proposed. The structure consists of a sigma-delta modulator which drives the half bridge switches directly. The output of the quantizer is taken as the feedback for the sigma-delta as usual, but this feedback signal goes to a one-bit digital-to- analog converter

  4. Analysis of Parallel-Connected Asymmetrical Soft-Switching Converter

    Microsoft Academic Search

    Bor-Ren Lin; Chao-Hsien Tseng

    2007-01-01

    A new half-bridge converter with two current-doubler rectifiers is proposed. Two transformers are used in the proposed converter. The primary windings of two transformers are connected in series to reduce the voltage stress across the magnetizing inductor, since each magnetizing inductor voltage is equal to one half of the input voltage. Two current-doubler rectifiers at the secondary sides are connected

  5. New configuration of 36-pulse voltage source converter with auxiliary circuit

    Microsoft Academic Search

    Byung-Moon Han; Seung-Taek Baek; Young-Soo Jon

    2006-01-01

    This paper proposes a new configuration of the 36-pulse voltage source converter, composed of two 6-pulse bridges and a pulse-interleaving\\u000a auxiliary circuit. The converter topology was devised to increase the number of pulses of the output voltage without increasing\\u000a the number of 6-pulse bridges and coupling transformers. The operational feasibility of the proposed system was verified by\\u000a computer simulations with

  6. Adding active clamping and soft switching to boost-flyback single-stage isolated power-factor-corrected power supplies

    Microsoft Academic Search

    Yim-Shu Lee; Bo-Tao Lin

    1997-01-01

    Single-stage isolated power-factor-corrected power supplies (SSIPP) have the attractive features of fast regulation and a single control loop. However, SSIPP circuits also have higher voltage stress and heavier loss (when compared with a normal DC-DC power converter), which severely limit their practical applications. In this paper, the authors propose to add active clamping to SSIPP to recycle the energy trapped

  7. Thermoacoustic Space Power Converter

    Microsoft Academic Search

    Emanuel Tward; Michael Petach; Scott Backhaus

    2003-01-01

    A thermoacoustic power converter for use in space in the conversion of radioisotope-generated heat to electricity is under development. The converter incorporates a thermoacoustic driver that converts heat to acoustic power without any moving parts. The acoustic power is used to drive a pair of flexure bearing supported pistons connected to voice coils in a vibrationally balanced pair of moving

  8. Convertible Bonds as \\

    Microsoft Academic Search

    Jeremy C. Stein

    1992-01-01

    This paper argues that corporations may use convertible bonds as an indirect (albeit possibly risky) method for getting equity into their capital structures in situations where adverse selection problems make a conventional stock issue unattractive. Unlike other theories of convertible bond issuance, the model of this paper highlights: 1) the importance of call provisions on convertibles; and 2) the significance

  9. Protocol Compatibility and Converter Synthesis Karin Avnit Vijay D'Silva Arcot Sowmya

    E-print Network

    New South Wales, University of

    protocols. 1 #12;1 Introduction Aimed at accelerating the design phase and increasing system reliability to as transducer, converter, wrapper or bridge) to be introduced to mediate between them. A general bus-based SoC architecture is illustrated in Figure 1. Bus Bridge IP1 IP4 IP2 Wrapper IP3 Wrapper IP6 IP7 Wrapper IP5 Bus

  10. A Two-Stage Isolated\\/Bidirectional DC\\/DC Converter With Current Ripple Reduction Technique

    Microsoft Academic Search

    Jun-Young Lee; Yu-Seok Jeong; Byung-Moon Han

    2012-01-01

    This letter suggests a two-stage isolated\\/bidirectional dc\\/dc converter with three bridges. Two bridges are used for electrical isolation and constant gain, and the bidirectional control is accomplished through only a single bridge. RMS currents in the high-voltage source and link capacitor can be alleviated by capacitor division and synchronizing oper- ation of both stages. This structure provides a simple control

  11. Surfacing of concrete bridges

    Microsoft Academic Search

    Vibeke Wegan

    The estimated life for concrete bridges in Denmark is 100 years. One condition to en- sure this long lifetime is waterproofing of the bridge deck together with a high quality asphalt pavement. The surfacing of the concrete bridge deck is important because the concrete should be protected against water and de-icing salts since these factors can lead to reduction of

  12. Rotorcraft convertible engine study

    NASA Technical Reports Server (NTRS)

    Gill, J. C.; Earle, R. V.; Mar, H. M.

    1982-01-01

    The objective of the Rotorcraft Convertible Engine Study was to define future research and technology effort required for commercial development by 1988 of convertible fan/shaft gas turbine engines for unconventional rotorcraft transports. Two rotorcraft and their respective missions were defined: a Fold Tilt Rotor aircraft and an Advancing Blade Concept (ABC) rotorcraft. Sensitivity studies were conducted with these rotorcraft to determine parametrically the influence of propulsion characteristics on aircraft size, mission fuel requirements, and direct operating costs (DOC). The two rotorcraft were flown with conventional propulsion systems (separate lift/cruise engines) and with convertible propulsion systems to determine the benefits to be derived from convertible engines. Trade-off studies were conducted to determine the optimum engine cycle and staging arrangement for a convertible engine. Advanced technology options applicable to convertible engines were studied. Research and technology programs were identified which would ensure technology readiness for commercial development of convertible engines by 1988.

  13. Nanoparticle bridge DNA biosensor

    NASA Astrophysics Data System (ADS)

    Huang, Hong-Wen

    A new DNA sensing method is demonstrated in which DNA hybridization events lead to the formation of nanoparticle satellites that bridge two electrodes and are detected electrically. The hybridization events are exclusively carried out only on specific locations, the surfaces of C-ssDNA modified 50 nm GNPs. The uniqueness of this work is that only a small number of T-ccDNA molecules (<10) is required to form the nanoparticle satellites, allowing ultra-sensitive DNA sensing. The principle of this new DNA sensing technique has been demonstrated using target DNA and three-base-pair-mismatched DNA in 20nM concentrations. Three single-stranded DNA (ssDNA) system is used in our experiment which includes Capture-ssDNA (C-ssDNA), Target-ssDNA (T-ssDNA) and Probe-ssDNA (P-ssDNA). Both C-ssDNA and P-ssDNA are modified by a thiol group and can hybridize with different portions of T-ssDNA. T-ssDNA requires no modification in three ssDNA system, which is beneficial in many applications. C-ssDNA modified 50nm gold nanoparticle (C-50au) and P-ssDNA modified 30nm gold nanoparticle (P-30au) are prepared through the reaction of thiol-gold chemical bonding between thiolated ssDNA and gold nanoparticle (GNP) (C-ssDNA with 50nm GNP, P-ssDNA with 30nm GNP). We controllably place the C-50au only on the SiO2 band surface (˜ 90nm width) between two gold electrodes (source and drain electrodes) by forming positively- and negatively-charged self-assembled monolayers (SAMs) on SiO2 and gold surface, respectively. DNA modified GNP is negatively charged due to ionization of phosphate group on DNA back bone. C-50au therefore is negatively charged and can only be attracted toward SiO2 area (repelled by negatively charged gold electrode surface). The amine group of positively-charged SAMs on SiO2 surface is then passivated by converting to non-polar methyl functional group after C-50au placement. P-30au is first hybridized with T-ssDNA in the solution phase (T-P- 30au formed) and is introduced into DNA detection device in which C-50au are immobilized on ˜90nm width SiO2 band (between two gold electrodes). The passivation step ensures every TP-30au are attached only to C-50au through hybridization (T-P-30au will not be attracted toward SiO2 surface or gold electrodes). GNP bridges are formed across the electrodes and provide an electrical path between two gold electrodes. We ensure that every T-P-30au only hybridizes on the surface of C-50au by (1) accurately controlling C-50au placement between two gold electrodes, (2) passivating positively-charged SAMs on SiO2 surface after C-50au immobilization. When T-P-30au hybridize with C-50au on ˜90nm wide SiO 2 surface, GNP bridges form and provide an electrical path between two gold electrodes even with only a few hybridization events. Experimental results show that even a few GNP bridges formed on SiO2 band can provide a significant conductance change from an open circuit to a conductive circuit (current = 0.5 uA at voltage = 0.1 V with four GNP bridge). We also used 3-base-pair-mismatched ssDNA (3mm-ssDNA) as a control experiment, which always resulted in an open circuit (no GNP bridge formed). Our detection device is compatible with current CMOS fabrication technology and can be manufactured on a wafer scale. The direct electrical output of this DNA detection technique provides a promising basis for high-throughput screening (can be fabricated on a wafer scale) with no expensive equipment required.

  14. Operation of a modular multilevel converter with selective harmonic elimination PWM

    Microsoft Academic Search

    Georgios S. Konstantinou; Mihai Ciobotaru; Vassilios G. Agelidis

    2011-01-01

    The modular multilevel converter (MMC) is based on the cascaded interconnection of half-bridge switching sub- modules and features modular characteristics that allow its expandability while providing high quality voltage and current output waveforms and removing the need for filtering. The switching frequency of each of the individual converter sub modules being maintained low and the balancing of the capacitor voltages

  15. Improved small-signal analysis for the phase-shifted PWM power converter

    Microsoft Academic Search

    Michael J. Schutten; David A. Torrey

    2003-01-01

    A closed form cycle by cycle analysis forms the basis for a new zero-voltage switching (ZVS) phase-shifted PWM (PSPWM) full bridge power converter small-signal model. The paper derives the small-signal response equations. The PSPWM converter has an implicit \\

  16. A multi-functional converter for a reduced cost, solar powered, water pump

    Microsoft Academic Search

    David Tschanz; Howard Lovatt; Andrea Vezzini; Virginien Perrenoud

    2010-01-01

    Solar powered water pumps classically use a boost converter for power point tracking followed by a motor inverter to drive the pump. This paper introduces a new, novel solution using a Multi-Functional Converter (MFC) that combines the boost function and the motor inverter function into a single, 6-switch, inverter bridge. Thus reducing cost and complexity and increasing reliability. The paper

  17. An improved soft switching PWM FB DC\\/DC converter for reducing conduction losses

    Microsoft Academic Search

    Eun-Soo Kim; Kee-Yeon Joe; Moon-Ho Kye; Yoon-Ho Kim; Byung-Do Yoon

    1996-01-01

    An improved soft switching topology of a full bridge PWM DC\\/DC converter is described. The new topology employs an energy recovery snubber to minimize a circulating current flowing through the transformer and switching devices. By using an energy recovery snubber instead of adding a tapped inductor and a saturable reactor to reduce RMS current stress, the converter achieves nearly zero

  18. A fuzzy set theory based control of a phase-controlled converter DC machine drive

    Microsoft Academic Search

    G. C. D. Sousa; Bimal K. Bose

    1994-01-01

    Fuzzy logic or fuzzy set theory is getting increasing emphasis in process control applications. The paper describes application of fuzzy logic in a speed control system that uses a phase-controlled bridge converter and a separately excited DC machine. The fuzzy control is used to linearize the transfer characteristics of the converter in discontinuous conduction mode occurring at light load and\\/or

  19. Realization of a three-phase indirect matrix converter with an indirect vector modulation method

    Microsoft Academic Search

    Matti Jussila; Mika Salo; Heikki Tuusa

    2003-01-01

    This paper presents the simulation and measurement results of a three-phase 5 kVA vector modulated indirect matrix converter (IMC). Functionally the IMC is very similar to the direct matrix converter (DMC) but it has separate line and load bridges. The indirect vector modulation method (IVM) is presented using space vector theory instead of conventional matrix form. Most research on IMC

  20. ITER convertible blanket evaluation

    SciTech Connect

    Wong, C.P.C.; Cheng, E.

    1995-09-01

    Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate.

  1. GraphicConverter

    NSDL National Science Digital Library

    GraphicConverter goes beyond the ability to convert a large number of graphic file formats. It provides tools for the creation and/or editing of graphics, animations, movies, and slide presentations; it also supports Adobe Photoshop compatible plug-ins. Currently, GraphicConverter can import 96 different graphic file formats and export 38. Conversion of several files (graphic or text) at a time is also possible through the "convert more..." feature. The tools offered for graphic editing are Photoshop-like. Detailed documentation is provided. This Macintosh shareware is provided by Lemke Software.

  2. Tapped inductor filter-assisted soft-switching PWM DC-DC power converter with high frequency transformer link for automotive AC power supply

    Microsoft Academic Search

    Serguei Moisseev; Y. Ishigami; K. Soshin; M. Nakaoka

    2004-01-01

    This paper presents a novel voltage source full-bridge type soft-switching phase-shift PWM controlled DC-DC power converter with a high frequency transformer link, which can operate under ZVS transition of leading bridge leg and ZCS transition of lagging bridge leg. This power converter can be used as power conditioner for small-scale solar photovoltaic cell and fuel cell power generation systems and

  3. LOOKING WNW, CHEVROLET AVENUE BRIDGE CROSSING FLINT RIVER. BRIDGE CONNECTED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LOOKING WNW, CHEVROLET AVENUE BRIDGE CROSSING FLINT RIVER. BRIDGE CONNECTED NORTH AND SOUTH PORTIONS OF FACTORY COMPLEX. DANIEL LUTEN DESIGNED THE BRIDGE, AND ILLINOIS BRIDGE COMPANY BUILT IT IN 1918. THE BRIDGE WAS THE SITE OF THE BATTLE OF RUNNING BULLS IN THE 1936-1937 GM SIT DOWN STRIKE. - Delphi Flint West, 300 Chevrolet Avenue, Flint, Genesee County, MI

  4. Dead time optimization method for power converter

    NASA Astrophysics Data System (ADS)

    Deselaers, C.; Bergmann, U.; Gronwald, F.

    2013-07-01

    This paper introduces a method for dead time optimization in variable speed motor drive systems. The aim of this method is to reduce the conduction time of the freewheeling diode to a minimum without generation of cross conduction. This results in lower losses, improved EMC, and less overshooting of the phase voltage. The principle of the method is to detect beginning cross currents without adding additional components in the half bridge like resistors or inductances. Only the wave shape of the phase voltage needs to be monitored during switching. This is illustrated by an application of the method to a real power converter.

  5. High-efficiency DC-DC converter for fuel cell applications: Performance and dynamic modeling

    Microsoft Academic Search

    Oday A. Ahmed; J. A. M. Bleijs

    2009-01-01

    In this paper a new current-fed full bridge DC-DC converter configuration for fuel cell applications is presented, which uses an active clamp and a voltage doubler to achieve a very high efficiency with a low turns ratio transformer. A comparison is made in this paper between a number of current-fed converter topologies, and it is shown that the proposed converter

  6. Small signal and large signal charge control models for a phase-shifted PWM converter

    Microsoft Academic Search

    S. M. khazraei; A. Rahmati; A. Abrishamifar

    2008-01-01

    Average switch models for both small signal and large signal performance of a phase-shifted full-bridge PWM (PS-FB-PWM) converter under charge control called charge-controlled ZVS-PWM switch (QC-ZVS-PWM) are developed in this paper. By substituting these models into cycle-by-cycle model of PS-FB-PWM converter the small signal and large signal behavior of the converter can be easily predicted. Implementation of these models in

  7. Analysis of a bi-directional DC-DC converter topology for low power application

    Microsoft Academic Search

    Manu Jain; Praveen K. Jain; Matteo Daniele

    1997-01-01

    This paper describes a bidirectional DC-DC converter for use in low power applications. The converter is based on a half-bridge in the primary side and on a current fed push-pull in the secondary of a high frequency isolation transformer. In the presence of the DC mains (provided by the AC mains), the converter essentially operates in the buck mode charging

  8. A Novel FB ZVS PWM DC-DC Converter Based on Digital Control

    Microsoft Academic Search

    Pinghua Tang; Guijie Yang; Tiecai Li; Yajing Liu

    2006-01-01

    Conventional full-bridge (FB) zero-voltage-switching (ZVS) PWM DC-DC converter has several disadvantages, such as serious loss of duty cycle, narrow range of ZVS of the lagging leg, and voltage overshoot in the secondary etc. This paper presents a novel FB ZVS PWM DC-DC converter, which adds two passive circuits based on the conventional FB DC-DC converter. One is paralleled in the

  9. An improved soft switching bi-directional PSPWM FB DC\\/DC converter

    Microsoft Academic Search

    Eun-Soo Kim; Kee-Yeon Joe; Hae-Young Choi; Yoon-Ho Kim; Yong-Hyun Cho

    1998-01-01

    A new soft switching isolated bi-directional phase shifted pulse width modulation (PSPWM) DC\\/DC converter is presented. Due to the use of the energy recovery snubber, the isolated bi-directional PSPWM DC\\/DC converter has a significant reduction of switching losses in the switching devices of the primary and secondary side bridge, respectively. The proposed soft switching bi-directional PSPWM FB DC\\/DC converter provides

  10. A new ZVS bidirectional DC-DC converter for fuel cell and battery application

    Microsoft Academic Search

    Fang Z. Peng; Hui Li; Gui-Jia Su; Jack S. Lawler

    2004-01-01

    This paper presents a new zero-voltage-switching (ZVS) bidirectional dc-dc converter. Compared to the traditional full and half bridge bidirectional dc-dc converters for the similar applications, the new topology has the advantages of simple circuit topology with no total device rating (TDR) penalty, soft-switching implementation without additional devices, high efficiency and simple control. These advantages make the new converter promising for

  11. The microminiature thermionic converter

    Microsoft Academic Search

    Donald Bryan King

    2000-01-01

    The design, fabrication, testing, and analysis of the microminiature thermionic converter (MTC) is discussed. MTCs are two electrode devices that convert heat energy into electrical energy. The electrodes are spaced opposite each other in a vacuum environment with one electrode heated and the second cooled. Electrons are emitted from the hot electrode to the cool electrode creating electrical power. The

  12. Nanoscale energy converters

    NASA Astrophysics Data System (ADS)

    Linke, Heiner

    2013-03-01

    An overview is given of the types of energy converters considered by this symposium: systems that make use of nanoscale phenomena and nanotechnology to achieve higher conversion efficiency, to achieve qualitatively enhanced performance, or to access new energy resources. The focus is on general concepts and principles, and approaches used by several nanoscale energy converters are identified.

  13. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, R.W. Jr.; Grubelich, M.C.

    1999-01-19

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge (SCB) igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length. 3 figs.

  14. Semiconductor bridge (SCB) detonator

    DOEpatents

    Bickes, Jr., Robert W. (Albuquerque, NM); Grubelich, Mark C. (Albuquerque, NM)

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  15. Photocapacitive image converter

    NASA Technical Reports Server (NTRS)

    Miller, W. E.; Sher, A.; Tsuo, Y. H. (inventors)

    1982-01-01

    An apparatus for converting a radiant energy image into corresponding electrical signals including an image converter is described. The image converter includes a substrate of semiconductor material, an insulating layer on the front surface of the substrate, and an electrical contact on the back surface of the substrate. A first series of parallel transparent conductive stripes is on the insulating layer with a processing circuit connected to each of the conductive stripes for detecting the modulated voltages generated thereon. In a first embodiment of the invention, a modulated light stripe perpendicular to the conductive stripes scans the image converter. In a second embodiment a second insulating layer is deposited over the conductive stripes and a second series of parallel transparent conductive stripes perpendicular to the first series is on the second insulating layer. A different frequency current signal is applied to each of the second series of conductive stripes and a modulated image is applied to the image converter.

  16. APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM BELOW, SHOWING VALVE TOWER TO RIGHT. VIEW FACING NORTH - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream, East Range, Wahiawa, Honolulu County, HI

  17. APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM ENTRY. VIEW FACING NORTHWEST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream, East Range, Wahiawa, Honolulu County, HI

  18. LOOKING WEST, BETWEEN READING DEPOT BRIDGE AND SKEW ARCH BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LOOKING WEST, BETWEEN READING DEPOT BRIDGE AND SKEW ARCH BRIDGE (HAER No. PA-116). - Philadelphia & Reading Railroad, Reading Depot Bridge, North Sixth Street at Woodward Street, Reading, Berks County, PA

  19. GOETHALS BRIDGE FROM NORTH SIDE OVER ARTHUR KILL. RAILROAD BRIDGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GOETHALS BRIDGE FROM NORTH SIDE OVER ARTHUR KILL. RAILROAD BRIDGE IN FOREGROUND - Goethals Bridge, Spanning Arthur Kill from New Jersey to Staten Island, Staten Island (subdivision), Richmond County, NY

  20. Plans: Poop Deck, Boat Deck, Housetop, Bridge Deck, Upper Bridge ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Plans: Poop Deck, Boat Deck, Housetop, Bridge Deck, Upper Bridge Deck, Navigating Bridge, Forecastle Deck, Upper Deck, Second Deck and Hold - Saugatuck, James River Reserve Fleet, Newport News, Newport News, VA

  1. 1. VIEW OF SWING BRIDGE FROM KEDZIE AVENUE BRIDGE, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW OF SWING BRIDGE FROM KEDZIE AVENUE BRIDGE, LOOKING EAST. - Chicago, Madison & Northern Railroad, Sanitary & Ship Canal Bridge, Spanning Sanitary & Ship Canal, east of Kedzie Avenue, Chicago, Cook County, IL

  2. Feasibility study of high frequency step-up transformer linked soft-switching PWM DC-DC converter with tapped inductor filter

    Microsoft Academic Search

    S. Moisseev; K. Suzuoka; T. Ahmed; M. Nakaoka

    2003-01-01

    This paper presents a novel high frequency transformer linked full-bridge type soft-switching phase-shift PWM control DC-DC power converter, which can be used as DC power conditioner for small-scale fuel cell power generation system as well as isolated step-up DC-DC power converter for automotive AC power supply. Using full-bridge soft-switching PWM DC-DC converter topology makes possible to use low voltage high

  3. TWIN SKEWED TRUSS RAILROAD BRIDGES NEAR BRIDGE STREET AT THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    TWIN SKEWED TRUSS RAILROAD BRIDGES NEAR BRIDGE STREET AT THE WEST END OF THE PLANT. THIS VIEW PROBABLY LOOKING NORTHWEST. BRIDGES BUILT OVER ERIE CANAL (WHICH FLOWED RIGHT THROUGH THE MIDDLE OF THE PLANT) BY AMERICAN BRIDGE COMPANY IN 1902. SINCE THIS PHOTO WAS TAKEN, NEAR BRIDGE HAS BEEN DEMOLISHED; FAR BRIDGE IS STILL IN SERVICE. - Solvay Process Company, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  4. Performance testing of a high frequency link converter for Space Station power distribution system

    NASA Technical Reports Server (NTRS)

    Sul, S. K.; Alan, I.; Lipo, T. A.

    1989-01-01

    The testing of a brassboard version of a 20-kHz high-frequency ac voltage link prototype converter dynamics for Space Station application is presented. The converter is based on a three-phase six-pulse bridge concept. The testing includes details of the operation of the converter when it is driving an induction machine source/load. By adapting a field orientation controller (FOC) to the converter, four-quadrant operation of the induction machine from the converter has been achieved. Circuit modifications carried out to improve the performance of the converter are described. The performance of two 400-Hz induction machines powered by the converter with simple V/f regulation mode is reported. The testing and performance results for the converter utilizing the FOC, which provides the capability for rapid torque changes, speed reversal, and four-quadrant operation, are reported.

  5. Bryce Canyon Natural Bridge

    USGS Multimedia Gallery

    The Bryce Canyon Natural Bridge. Technically, this is not a natural bridge, which forms when running water erodes a tunnel into a rock formation. Instead, this is a natural arch, similar to the ones in nearby Arches National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is...

  6. Bridge Program Planning Guide

    NSDL National Science Digital Library

    Jenkins, Davis

    This report discusses bridge training programs which are designed to "prepare individuals without the requisite basic skills for postsecondary training leading to career-path employment and further learning in a specific industry or occupational sector." This guide is intended to help those representing community colleges, community organizations, and others plan the development of bridge training programs.

  7. STEM Bridge Scholarship Program

    E-print Network

    Buehrer, R. Michael

    2015-2016 STEM Bridge Scholarship Program Virginia Space Grant Consortium (VSGC) provides renewable STEM Bridge Scholarships of $1,000 to sophomore students from any federally recognized minority group enrolled full-time in a program of study in science, technology, engineering, or math (STEM) at one

  8. Virtual Bridge Design Challenge

    ERIC Educational Resources Information Center

    Mitts, Charles R.

    2013-01-01

    This design/problem-solving activity challenges students to design a replacement bridge for one that has been designated as either structurally deficient or functionally obsolete. The Aycock MS Technology/STEM Magnet Program Virtual Bridge Design Challenge is an authentic introduction to the engineering design process. It is a socially relevant…

  9. Bridge Monitoring and Loading

    E-print Network

    of a dedicated opera- tional modal analysis suite of hardware and software, and the increasing realisation;2 Bridge-Friendly Truck Suspensions Short-span bridge dynamic responses to heavy vehicle crossing events can be reduced through adjustment of the vehicle suspension damping coefficient just before

  10. Pedestrian excitation of bridges

    Microsoft Academic Search

    D E Newland

    2004-01-01

    This paper reviews the evidence on dynamic bridge loading caused by moving pedestrians. The phenomenon of ' synchronization' by which people respond naturally to an oscillating bridge when this has a frequency close to their natural walking or running frequency is a feature of this phenomenon. By increasing modal damping, synchronization can be prevented, but how much damping is needed

  11. Thermoacoustic Space Power Converter

    NASA Astrophysics Data System (ADS)

    Tward, Emanuel; Petach, Michael; Backhaus, Scott

    2003-01-01

    A thermoacoustic power converter for use in space in the conversion of radioisotope-generated heat to electricity is under development. The converter incorporates a thermoacoustic driver that converts heat to acoustic power without any moving parts. The acoustic power is used to drive a pair of flexure bearing supported pistons connected to voice coils in a vibrationally balanced pair of moving coil alternators. Initial tests of the small ~100W thermoacoustic driver have demonstrated good efficiency. An alternator matched to the driver is now under construction. A description of the system and the results of development tests are presented.

  12. Microminiature thermionic converters

    DOEpatents

    King, Donald B. (Albuquerque, NM); Sadwick, Laurence P. (Salt Lake City, UT); Wernsman, Bernard R. (Clairton, PA)

    2001-09-25

    Microminiature thermionic converts (MTCs) having high energy-conversion efficiencies and variable operating temperatures. Methods of manufacturing those converters using semiconductor integrated circuit fabrication and micromachine manufacturing techniques are also disclosed. The MTCs of the invention incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. Existing prior art thermionic converter technology has energy conversion efficiencies ranging from 5-15%. The MTCs of the present invention have maximum efficiencies of just under 30%, and thousands of the devices can be fabricated at modest costs.

  13. Fluorescent radiation converter

    NASA Technical Reports Server (NTRS)

    Viehmann, W.

    1980-01-01

    Fluorescent radiation converter used optically transparent substrate. One side of substrate is coated with plastic film containing fluorescent organic dyes that absorb optical radiation at one wavelength and emit it at longer one. Coating is formulated to respond to specific wavelengths. Emitted radiation is reflected internally inside substrate, amplifying intensity that reaches radiation detector. Converter can be made in several shapes and size; round and square bars coated all round their lengths are useful in converting relatively intense radiation and transmitting it through substrate over lengthy distances.

  14. A high-efficiency soft-switched AC\\/DC converter with current-doubler synchronous rectification

    Microsoft Academic Search

    Huang-Jen Chiu; Li-Wei Lin

    2005-01-01

    An improved ac\\/dc converter based on asymmetrical half-bridge topology is proposed in this paper. To substantially enhance the efficiency for low-voltage\\/high-current output applications, a current-doubler synchronous rectifier is combined with a modified asymmetrical half-bridge converter that retains the inherent zero-voltage-switching property. The power losses in the secondary rectification stage and the primary switches can be significantly reduced. The proposed architecture

  15. New dc rail side soft-switching PWM dc-dc converter with high frequency planar transformer

    Microsoft Academic Search

    Khairy Sayed; Keiki Morimoto; Soon-Kurl Kwon; Katsumi Nishida; Mutsuo Nakaoka

    2011-01-01

    This paper presents a new circuit topology of active edge resonant snubbers assisted half-bridge soft switching PWM inverter type dc-dc high power converter for DC bus feeding power plants. The proposed dc-dc power converter is composed of typical voltage source-fed half- bridge high frequency PWM inverter with a high frequency planar transformer link in addition to input DC busline side

  16. Building Our Bridge to Fun!

    NSDL National Science Digital Library

    AMPS GK-12 Program,

    Students identify different bridge designs and construction materials used in modern day engineering. They work in construction teams to create paper bridges and spaghetti bridges based on existing bridge designs. Students progressively realize the importance of the structural elements in each bridge. They also measure vertical displacements under the center of the spaghetti bridge span when a load is applied. Vertical deflection is measured using a LEGO® MINDSTORMS® NXT intelligent brick and ultrasonic sensor. As they work, students experience tension and compression forces acting on structural elements of the two bridge prototypes. In conclusion, students discuss the material properties of paper and spaghetti and compare bridge designs with performance outcomes.

  17. Circuit bridging of components by smoke

    SciTech Connect

    Tanaka, T.J.; Nowlen, S.P.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States)

    1996-10-01

    Smoke can adversely affect digital electronics; in the short term, it can lead to circuit bridging and in the long term to corrosion of metal parts. This report is a summary of the work to date and component-level tests by Sandia National Laboratories for the Nuclear Regulatory Commission to determine the impact of smoke on digital instrumentation and control equipment. The component tests focused on short-term effects such as circuit bridging in typical components and the factors that can influence how much the smoke will affect them. These factors include the component technology and packaging, physical board protection, and environmental conditions such as the amount of smoke, temperature of burn, and humidity level. The likelihood of circuit bridging was tested by measuring leakage currents and converting those currents to resistance in ohms. Hermetically sealed ceramic packages were more resistant to smoke than plastic packages. Coating the boards with an acrylic spray provided some protection against circuit bridging. The smoke generation factors that affect the resistance the most are humidity, fuel level, and burn temperature. The use of CO{sub 2} as a fire suppressant, the presence of galvanic metal, and the presence of PVC did not significantly affect the outcome of these results.

  18. Thermionic photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, D. L. (inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  19. Gallium phosphide energy converters

    Microsoft Academic Search

    P. E. Sims; L. C. Dinetta; M. A. Goetz

    1995-01-01

    Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need

  20. A single-phase full-bridge charger with regeneration and adjustable power factor

    Microsoft Academic Search

    Gwo Jen Chiou; Hsin Yu Lin; Tsung Cheng Chen; Jeng Yue Chen

    2009-01-01

    The paper proposes a single-phase full-bridge positive\\/negative pulse charger with energy regeneration and adjustable power factor. Based on a generalized zero vector technique, a novel charging system which combines a single-phase boost rectifier with a buck converter is presented. The system forms a novel single-stage converter of AC to DC, and such a converter has both energy regeneration and power

  1. 47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007...MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge...Bridge-to-bridge radiotelephone installation. Use of the...

  2. 47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007...MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge...Bridge-to-bridge radiotelephone installation. Use of the...

  3. 47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007...MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge...Bridge-to-bridge radiotelephone installation. Use of the...

  4. 47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007...MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge...Bridge-to-bridge radiotelephone installation. Use of the...

  5. 47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007...MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge...Bridge-to-bridge radiotelephone installation. Use of the...

  6. Bay Bridge 360

    NSDL National Science Digital Library

    This website was created by the various California transportation agencies that are involved in the enormous job of retrofitting the San Francisco-Oakland Bay Bridge to protect it from being damaged by seismic activity. It is an extremely well thought out website, with an interactive aerial graphic of the Bridge on its homepage that introduces visitors to their work. If you click on the colored circles on the bridge, you can see a slideshow of the construction on that section of the Bridge, and some of the Bridge sections include a time-lapse video of the construction. Additionally, there is a short film visitors can watch to get an overview of the project, by clicking on the blue circle above "Bay Bridge Overview" in the right-hand corner of the homepage. Clicking on the arrow in the left-hand corner of the homepage takes you inside the website where you can find links to "Closures and Detours", "Environmental Issues", for the Final Environmental Impact Statement, detailed explanations of the construction methods under the "Information Center" link, and even "Construction Cams". If you just can't get enough of traffic where you live, just click on "Construction Cams" and see Bay Bridge traffic.

  7. 5. View of Clark Fork Vehicle Bridge facing east. Bridge ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. View of Clark Fork Vehicle Bridge facing east. Bridge from south shore of Clark Fork River-southernmost span. 1900-era Northern Pacific Railway Bridge in background. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

  8. Inherent overload protection for the series resonant converter

    NASA Technical Reports Server (NTRS)

    King, R. J.; Stuart, T. A.

    1983-01-01

    The overload characteristics of the full bridge series resonant power converter are considered. This includes analyses of the two most common control methods presently in use. The first of these uses a current zero crossing detector to synchronize the control signals and is referred to as the alpha controller. The second is driven by a voltage controlled oscillator and is referred to as the gamma controller. It is shown that the gamma controller has certain reliability advantages in that it can be designed with inherent short circuit protection. Experimental results are included for an 86 kHz converter using power metal-oxide-semiconductor field-effect transistors (MOSFETs).

  9. Multilevel converters-a new breed of power converters

    Microsoft Academic Search

    Jih-Sheng Lai; Fang Zheng Peng

    1996-01-01

    Multilevel voltage source converters are emerging as a new breed of power converter options for high-power applications. The multilevel voltage source converters typically synthesize the staircase voltage wave from several levels of DC capacitor voltages. One of the major limitations of the multilevel converters is the voltage unbalance between different levels. The techniques to balance the voltage between different levels

  10. Bridge : an unraveled architecture

    E-print Network

    ElHusseiny, Ahmed

    2006-01-01

    The bridge is an inhabitable structure housing live/work artists studios, galleries and workshops. It is an urban/architectural/personal intervention that strives to explore issues of Iatent/potential narratives within a ...

  11. Build Your Bridge

    NSDL National Science Digital Library

    These interactive learning modules and simulations allow students to explore the science, technology and people involved in building the New Bay Bridge, which is intended as a replacement for the historic San Francisco-Oakland Bay Bridge that was damaged in the 1989 Loma Prieta Earthquake. In the interactive module "Quake Country," students investigate plate tectonics as the driving force behind the faulting and resulting earthquakes in the Bay area. In the "Engineering for Earthquakes" simulation, students act as engineers, design their own bridges, and test them against the Maximum Credible Earthquake (MCE), the worst earthquake that might hit the Bay area every 1500 years. In the module "Two Miles and 2,000 Hands," students learn about the people who perform a large variety of jobs in building the new bridge.

  12. Implant-Supported Bridge

    MedlinePLUS

    ... made by the dental lab. Porcelain-fused-to-metal bridge The restoration (the part that looks like ... porcelain attached and fused to a framework of metal. The Implant Process The time it takes to ...

  13. Bridge Rectifier Animation

    NSDL National Science Digital Library

    This is an animation of a bridge rectifier circuit or diode bridge. Voltages and parts of the circuit of this 3-D animated gif are highlighted with different colors. Current is displayed by green arrows indicating directional flow. The animation requires a Web browser or other video player software capable of displaying gif animations. A link provides an optional Quicktime version of this same animation.Other 3-D Circuit Animations can be seen here.

  14. Valve bridge construction method

    SciTech Connect

    Greene, H.F.

    1987-07-07

    This patent describes an improved method of rebuilding a used valve bridge assembly of the type that actuates the exhaust valves in a cylinder of a diesel locomotive engine, the bridge including a cross-arm with distal ends and lash adjuster sockets adjacent to each of the distal ends. Each of the lash adjuster sockets has an opening adapted to receive a lash adjuster by being press-fit in order to provide smooth, efficient operation of the exhaust valves. The bridge has at least one lash adjuster socket with an inner diameter worn oversized so that a standard size lash adjuster can no longer be properly fitted. The improved method of: maintaining a stock of oversized lash adjusters which each include an outer cylindrical wall having a radially outwardly projecting rib member adapted to be in surface-to-surface contact with the inner surface of the lash adjuster sockets. An outer diameter dimension then is larger in diameter than the outer diameter dimension of the corresponding rib on the standard size lash adjuster; disassembling the used valve bridge, including removing the used lash adjusters from each of the lash adjuster sockets; cleaning the valve bridge, including the lash adjuster sockets formed without machining the lash adjuster sockets in the valve bridge; measuring the inner diameter dimension of each of the oversized lash adjuster sockets in the valve bridge; selecting an oversized lash adjuster from the stock of oversized lash adjusters an outer diameter dimension comparable to the measured inner diameter dimension of each of the oversized lash adjuster sockets; and reassembling the valve bridge, including press-fitting the selected oversized lash adjuster into the measured lash adjuster socket so that the radially outwardly projecting rib member is in surface to surface contact with the inner surface of the measured lash adjuster socket.

  15. Rotorcraft convertible engine study

    NASA Technical Reports Server (NTRS)

    Goldstein, D. N.; Hirschkron, R.; Smith, C. E.

    1983-01-01

    Convertible propulsion systems for advanced rotorcraft are evaluated in terms of their impact on aircraft operating economics and fuel consumption. A variety of propulsion system concepts, including separate thrust and power producing engines, convertible fan/shaft engines, and auxiliary propeller configurations are presented. The merits of each are evaluated in two different rotorcraft missions: an intercity, commercial transport of the ABC(TM) type, and an offshore oil ring supply ship of the X-wing type. The variable inlet guide vane fan/shaft converting engine and auxiliary propeller configurations are shown to offer significant advantages over all the other systems evaluated, in terms of both direct operating cost and fuel consumption.

  16. Inductorless DC-AC Cascaded H-bridge Multilevel Boost Inverter for Electric/Hybrid Electric Vehicle

    E-print Network

    Tolbert, Leon M.

    - DC boost converter to boost the battery voltage for a traditional 3-phase inverter. The present HEV) and an H-bridge in series with each inverter leg which uses a capacitor as the DC power source. Fundamental that the proposed inductorless DC-AC cascaded H-bridge multilevel boost inverter can output a boosted AC voltage. I

  17. Thermionic energy converter investigations

    NASA Technical Reports Server (NTRS)

    Goodale, D. B.; Lee, C.; Lieb, D.; Oettinger, P. E.

    1979-01-01

    This paper presents evaluation of a variety of thermionic converter configurations to obtain improved efficiency. A variable-spacing diode using an iridium emitter gave emission properties comparable to platinum, but the power output from a sintered LaB6 collector diode was not consistent with its work function. Reflectivities above 0.5 were measured at thermal energies on oxygenated-cesiated surfaces using a field emission retarding potential gun. Performance of converters with structured electrodes and the characteristics of a pulsed triode were studied as a function of emitter, collector, cesium reservoir, interelectrode spacing, xenon pressure, and pulsing parameters.

  18. A Soft-Switched Three-Port Bidirectional Converter for Fuel Cell and Supercapacitor Applications

    Microsoft Academic Search

    H. Tao; A. Kotsopoulos; J. L. Duarte; M. A. M. Hendrix

    2005-01-01

    This paper presents a zero-voltage-switching (ZVS) three-port bidirectional converter for fuel cell and supercapacitor applications. A simple and effective method to extend the soft-switching range is proposed, especially for the three-port active-bridge topology. By continuously adjusting the duty cycle on the supercapacitor side H-bridge according to the supercapacitor voltage level, soft-switching conditions are achieved over the full operating range due

  19. A ZVZCS PWM FB DC\\/DC converter using a modified energy-recovery snubber

    Microsoft Academic Search

    Eun-Soo Kim; Yoon-Ho Kim

    2002-01-01

    The conventional high-frequency phase-shifted zero-voltage-switching (ZVS) full-bridge DC\\/DC converter has a disadvantage, in that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current, RMS current stress, conduction losses of the transformer and switching devices are increased. To alleviate this problem, this paper proposes an improved zero-voltage zero-current switching (ZVZCS) phase-shifted full-bridge

  20. An improved ZVZCS PWM FB DC\\/DC converter using energy recovery snubber

    Microsoft Academic Search

    Eun-Soo Kim; Kee-Yeon Joe; Moon-Ho Kye; Yoon-Ho Kim; Byung-Do Yoon

    1997-01-01

    The conventional high frequency phase-shifted full-bridge DC\\/DC power converter has a disadvantage that a circulating current flows through the transformer and switching devices during the freewheeling interval. Due to this circulating current, RMS current stress, conduction losses of transformer and switching devices are increased. To alleviate this problem, this paper provides a circulating current free-type high-frequency ZVZCS phase-shifted full bridge

  1. Converting triangulations to quadrangulations

    Microsoft Academic Search

    Suneeta Ramaswamia; Pedro Ramos; Godfried Toussaint

    1995-01-01

    We study the problem of converting triangulated domains to quadrangulations, under a variety of constraints. We obtain a variety of characterizations for when a triangulation (of some structure such as a polygon, set of points, line segments or planar subdivision) admits a quadrangulation without the use of Steiner points, or with a bounded number of Steiner points. We also investigate

  2. Catalytic Converters and Nanocatalysts

    NSDL National Science Digital Library

    This lab, presented by the National Nanotechnology Infrastructure Network, covers the concept of chemical reactions. Students will learn about "the reactions involved in catalytic converters and the importance of nanocatalysts in the reactions." Teacher Preparation Guides, Student Guides, and Next Generation Science Standards applicable to the lesson are included.

  3. Hydro current energy converter

    Microsoft Academic Search

    Rauch

    1985-01-01

    A hydro-dynamic device for capturing the energy of a natural stream of flowing water, and converting such current or flow of water energy into electric power for user consumption. The device has a primary tubular housing, a sealed, conical, secondary housing containing an electrical generator. The secondary housing has a conical end portion, and is disposed within and along the

  4. ZVS-SR bidirectional DC-DC converter for supercapacitor-applied automotive electric energy storage systems

    Microsoft Academic Search

    T. Mishima; Eiji Hiraki

    2005-01-01

    This paper explores a bidirectional DC-DC converter for supercapacitor-based energy storage systems in automotive applications. The presented converter consists of a half-bridge converter and a current-fed push-pull inverter with a transformer-isolation. Owing to the isolation topology, the supercapacitor can be operated in the wide voltage range, which results in an increase in the utilization of supercapacitor-stored energy. In order to

  5. A three-phase soft-switched high-power-density DC\\/DC converter for high-power applications

    Microsoft Academic Search

    Rik W. A. A. De Doncker; Deepakraj M. Divan; Mustansir H. Kheraluwala

    1991-01-01

    Three DC\\/DC converter topologies suitable for high-power-density high-power applications are presented. All three circuits operate in a soft-switched manner, making possible a reduction in device switching losses and an increase in switching frequency. The three-phase dual-bridge converter proposed is shown to have the most favorable characteristics. This converter consists of two three-phase inverter stages operating in a high-frequency six-step mode.

  6. A three-phase soft-switched high power density DC\\/DC converter for high power applications

    Microsoft Academic Search

    R. W. De Doncker; D. M. Divan; M. H. Kheraluwala

    1988-01-01

    The authors present three DC\\/DC converter topologies suitable for high-power-density high-power applications. All three circuits operate in a soft-switched manner, making possible a reduction in device switching losses and an increase in switching frequency. The three-phase dual-bridge converter proposed is seen to have the most favorable characteristics. This converter consists of two three-phase inverter stages operating in a high frequency

  7. 22. BRIDGE CREEK BRIDGE, AVENUE OF THE GIANTS, OLD HIGHWAY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. BRIDGE CREEK BRIDGE, AVENUE OF THE GIANTS, OLD HIGHWAY 101. HUMBOLDT COUNTY, CALIFORNIA. LOOKING E. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

  8. Dog Bridge, view of the deck of the bridge and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Dog Bridge, view of the deck of the bridge and rails looking from Linden Lane - National Park Seminary, Bounded by Capitol Beltway (I-495), Linden Lane, Woodstove Avenue, & Smith Drive, Silver Spring, Montgomery County, MD

  9. 4. VIEW OF SILVER BRIDGE (ST. MARY'S BRIDGE), CARRYING COUNTY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF SILVER BRIDGE (ST. MARY'S BRIDGE), CARRYING COUNTY ROAD OVER SOURIS RIVER NEAR SOUTH END OF REFUGE, LOOKING NORTHEAST - Upper Souris National Wildlife Refuge Dams, Souris River Basin, Foxholm, Ward County, ND

  10. Multilevel converters -- A new breed of power converters

    SciTech Connect

    Lai, J.S. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.; Peng, F.Z. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States)

    1995-09-01

    Multilevel voltage source converters are emerging as a new breed of power converter options for high-power applications. The multilevel voltage source converters typically synthesize the staircase voltage wave from several levels of dc capacitor voltages. One of the major limitations of the multilevel converters is the voltage unbalance between different levels. The techniques to balance the voltage between different levels normally involve voltage clamping or capacitor charge control. There are several ways of implementing voltage balance in multilevel converters. Without considering the traditional magnetic coupled converters, this paper presents three recently developed multilevel voltage source converters: (1) diode-clamp, (2) flying-capacitors, and (3) cascaded-inverters with separate dc sources. The operating principle, features, constraints, and potential applications of these converters will be discussed.

  11. Thermionic energy converters

    NASA Technical Reports Server (NTRS)

    Morris, J. F. (inventor)

    1983-01-01

    The efficiency of thermionic energy converters is improved by internal distribution of tiny sorted cesium diodes driven by the thermal gradient between the primary emitter and the collector. The tiny, sorted diode distribution comprises protrusions of the emitter material from the main emitter face which contact the main collector face thermally but not electrically. The main collector ends of the protrusions are separated from the main collector by a thin layer of insulation, such as aluminum oxide. The shorted tiny diode distribution augments cesium ionization through internal thermal effects only within the main diode. No electrical inputs are required. This ionization enhancement by the distribution of the tiny shorted diodes not only reduces the plasma voltage drop but also increases the power output and efficiency of the overall thermionic energy converter.

  12. A Transformerless Medium-Voltage STATCOM Topology Based on Extended Modular Multilevel Converters

    Microsoft Academic Search

    M. Tavakoli Bina

    2011-01-01

    A new transformerless four-leg topology is suggested for shunt compensation, the modular multilevel converters (MMC) based on the half-bridge converters, to achieve higher perfor- mance as a STATCOM in a distorted and unbalanced medium- voltage large-current (MV-LC) system. Further, an extended MMC (EMMC) is proposed in order to manage more accurate compen- sation for high-power applications. Both proposals can be

  13. Design of a transcutaneous energy transmission system using a series resonant converter

    Microsoft Academic Search

    Ali Ghahary; B. H. Cho

    1990-01-01

    A full-bridge, zero-voltage-switched, series resonant converter which transfers 12-48 W of power (regulated voltage) across a large, variable air gap has been designed and built. This converter can power an artificial heart through intact skin by utilizing a transformer with an air gap of 1-2 cm between the primary winding and the secondary winding. The secondary winding would be implanted

  14. A novel soft-switching and low-conduction-loss bidirectional DC-DC converter

    Microsoft Academic Search

    Gang Chen; Yin-Shu Lee; Dehong Xu; Yousheng Wang

    2000-01-01

    A novel soft-switching and low-conduction-loss bidirectional DC-DC converter is proposed. Designed for low-output voltage applications, the converter has a full-bridge circuit on the primary side and a current-fed push-pull circuit on the secondary side. The flow of current is controlled by phase-shift pulse-width modulation. By adding an active-clamp circuitry on the secondary side and using suitable gate drives, not only

  15. An improved soft-switching PWM FB DC\\/DC converter for reducing conduction losses

    Microsoft Academic Search

    Eun-Soo Kim; Kee-Yeon Joe; Moon-Ho Kye; Yoon-Ho Kim; Byung-Do Yoon

    1999-01-01

    An improved soft-switching topology of a full-bridge (FB) pulsewidth-modulated (PWM) DC\\/DC converter is described. The new topology employs an energy-recovery snubber to minimize a circulating current flowing through the transformer and switching devices. By using an energy-recovery snubber instead of adding a tapped inductor and a saturable reactor to reduce RMS current stress, the converter achieves zero-current switching (ZCS) for

  16. Converting Informix 4GLApplications to Informix Genero Why Convert?

    E-print Network

    Converting Informix 4GLApplications to Informix Genero Why Convert? Your Informix 4GL applications. This is normal; your forms layouts respect the structure of IBM® Informix® 4GL. With a few minor modifications will be a state-of-the-art graphical application. Considerations for Converting I-4GL/D-4GL to Informix Genero

  17. The floating water bridge The floating water bridge

    E-print Network

    Podgornik, Rudolf

    The floating water bridge The floating water bridge Elmar C. Fuchs1 , Jakob Woisetschläger2 , Karl ____________________________________________ Abstract When high voltage is applied to distilled water filled into two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed

  18. SoftBridge: A Multimodal Instant Messaging Bridging System

    E-print Network

    Blake, Edwin

    1 SoftBridge: A Multimodal Instant Messaging Bridging System John Lewis, William Tucker and Edwin}@cs.uct.ac.za Abstract-- Instant Messaging is traditionally a text only affair. However, there are instances when framework that enables this kind of communications bridging us- ing instant messages. Its use of protocols

  19. Retrofitted Bridge Fragility Analysis for Typical Classes of Multispan Bridges

    Microsoft Academic Search

    Jamie E. Padgett; Reginald DesRoches

    2009-01-01

    Retrofitted bridge fragility curves provide a powerful tool for assessing the effect of retrofit measures on the seismic performance of different bridge types under a range of loading levels. Traditional methods for retrofit assessment typically evaluate the effectiveness of retrofit based on the performance of individual components. However, the use of fragility curves for retrofitted bridges has the ability to

  20. A full bridge soft switched telecom power supply with a current doubler rectifier

    Microsoft Academic Search

    Nasser H. Kutkut

    1997-01-01

    This paper presents a full bridge soft switched PWM telecom power supply with a current doubler rectifier. The full bridge PWM DC-to-DC power converter offers high power handling capability, minimum VA ratings for the main devices, no additional auxiliary components and simple PWM-based control strategy. Phase shift control is employed to regulate the output voltage and achieve soft switching. The

  1. A Novel Type DC Rail-Series Switch and Parallel Capacitor Snubber-Assisted Soft Switching PWM DC-DC Converter with High Frequency Transformer

    Microsoft Academic Search

    Tarek Ahmed; K. Morimoto; Mutsuo Nakaoka; T. Doi

    2005-01-01

    This paper presents a new circuit topology of DC bus line switch-assisted full-bridge soft switching PWM inverter type DC-DC converter. The proposed power converter is composed of typical voltage source H full-bridge high frequency PWM inverter with a high frequency transformer link in addition to a single DC bus line side power semiconductor switching device for PWM control scheme and

  2. A Novel Low-Voltage \\/ High-Current ZCS-PWM DC DC Converter with Asymmetrical Auxiliary Edge-Resonant Lossless Snubber

    Microsoft Academic Search

    Tomokazu Mishima; Eiji Hiraki; Toshihiko Tanaka; Mutsuo Nakaoka

    2007-01-01

    A novel zero current soft-swithing PWM half-bridge DC-DC converter topology is proposed in this paper. The newly proposed converter consists of a PWM-controlled half-bridge inverter and a current doubler rectifier linked with a high- frequency transformer. In order to attain the wide range of soft switching operation in the high voltage\\/low current primary side inverter, asymmetrical lossless snubbers composed by

  3. Monitoring Bridge Deterioration Using Sensors

    Microsoft Academic Search

    Bijan Samali; Jianchun Li; Khalid Aboura

    2008-01-01

    Structural health monitoring is a vital part in the management of bridges, particularly as the structures begin to age. Detecting structural faults through the use of sensors is an emerging field that has seen considerable efforts this past decade. Similarly, the use of sensors in bridge management systems provides valuable data on the condition of bridges and external factors affecting

  4. Quantum Bidding in Bridge

    NASA Astrophysics Data System (ADS)

    Muhammad, Sadiq; Tavakoli, Armin; Kurant, Maciej; Paw?owski, Marcin; ?ukowski, Marek; Bourennane, Mohamed

    2014-04-01

    Quantum methods allow us to reduce communication complexity of some computational tasks, with several separated partners, beyond classical constraints. Nevertheless, experimental demonstrations of this have thus far been limited to some abstract problems, far away from real-life tasks. We show here, and demonstrate experimentally, that the power of reduction of communication complexity can be harnessed to gain an advantage in a famous, immensely popular, card game—bridge. The essence of a winning strategy in bridge is efficient communication between the partners. The rules of the game allow only a specific form of communication, of very low complexity (effectively, one has strong limitations on the number of exchanged bits). Surprisingly, our quantum technique does not violate the existing rules of the game (as there is no increase in information flow). We show that our quantum bridge auction corresponds to a biased nonlocal Clauser-Horne-Shimony-Holt game, which is equivalent to a 2?1 quantum random access code. Thus, our experiment is also a realization of such protocols. However, this correspondence is not complete, which enables the bridge players to have efficient strategies regardless of the quality of their detectors.

  5. Building Migratory Bridges

    ERIC Educational Resources Information Center

    Roy, Michael; Doss, Laurie K.

    2007-01-01

    The Building Migratory Bridges (BOMB) program--a collaboration between the Marvel wood School and Audubon Sharon in Connecticut and Conservation Research Education Action (CR EA), a U.S. not-for-profit in Panama--uses nontropical migratory bird research in the United States and Panama to demonstrate how negative environmental impacts in one…

  6. JHU Bridge Designer

    NSDL National Science Digital Library

    Michael Karweit

    The Bridge Designer is a web-based program that allows the user to design and analyze 2-Dimensional statically determinate trusses. The user can specify support types (fixed or rolling) and locations, as well as the locations of various truss nodes and members.

  7. The Bridges Program.

    ERIC Educational Resources Information Center

    Bohnen, Elizabeth; Klie, Judy

    This report describes BRIDGES, an employment equity special measures training program developed by the City of Toronto (Ontario, Canada). It was designed to help women employees move from their traditional jobs into trades, technical or operation (TTO) jobs within their own organization. The program is a combination of classroom sessions, shop…

  8. Bridging the Gap?

    ERIC Educational Resources Information Center

    Salter, Colin

    2009-01-01

    The political context of the conversion of the Historic Tramway Bridge, adjacent to Sandon Point in Bulli (NSW, Australia), and how this was exploited to serve predetermined ends, illustrates that technologies can be designed to have particular social (and political) effects. Through reflection on this relatively small engineering project, this…

  9. DOE Information Bridge

    E-print Network

    United States. Department of Energy. Office of Scientific and Technical Information

    DOE Information Bridge, a component of EnergyFiles, provides free, convenient, and quick access to full-text DOE research and development reports in physics, chemistry, materials, biology, environmental sciences, energy technologies, engineering, computer and information science, renewable energy, and other topics. This vast collection includes over 43,000 reports that have been received and processed by OSTI since January 1995.

  10. Electrothermodynamic (etd) power converter

    SciTech Connect

    Marks, A.M.

    1983-07-26

    These inventions relate to novel advances in Electrothermodynamics (ETD), also known as charged aerosol, heat/electric power generators: (1) A new more efficient, compact converging/diverging configuration comprising a torus of revolution (TORON) used with a gas flywheel. (2) A ''Method II'' two-fluid mixed flow ejector/converter in a gas flywheel loop employing a primary steam or a high molecular weight driver jet such as a fluorocarbon containing charged aerosol water droplets and a low molecular weight carrier gas such as hydrogen or helium with an electro-negative gas additive, in a Rankine cycle including a vapor/gas and liquid separator with a bypass to the ejector/converter loop. (3) A ''Method III'' two-fluid mixed flow comprising a supersonic jet expanding conically within a subsonic flow, separated by a boundary layer in which the charged aerosol forms downstream of the orifice, at a cross section of at least 100 times the orifice section; and in which the electric charge density of the charged aerosol decreases along the jet axis, whereby substantially all of the kinetic power of the jet is converted to electric power within the jet, there being no ejector. (4) An array of supersonic jets utilizing Method III. (5) An array of supersonic jets utilizing Method III without separating duct walls in which ''convection cells'' provide return flows, forming a plurality of TORON configurations. (6) A supercritical Rankline cycle in a single stage employing Method III. (7) A method IV two-fluid cycle uses charged aerosols in an inert gas and operates on an Ericsson-type cycle. (8) Optimum operating conditions are defined for Methods II, III, and IV. (9) A high potential emitter is employed with a grounded body, and a sapphire tube sealed to metal by a new technique provides an insulating duct for the high temperature, high pressure vapor.

  11. 164 Currencies Converter

    NSDL National Science Digital Library

    Olsen and Associates of Zurich, Switzerland, a "developer of online forecasting technology for business and finance" has made this simple and fun service available. Simply enter the amount of currency for any of 164 currencies, the currency to be converted to, and the date of the exchange rate (back to January 1, 1990, in day/month/year format) into an online form, and presto, an exchange rate (which is then reversible) is obtained. As this is a demonstration product, neither multiple currencies nor multiple dates are allowed. Users should also read the FAQ to understand why the rate they get might be slightly different from the one their bank advertises.

  12. Cycloidal Wave Energy Converter

    SciTech Connect

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

  13. Gallium phosphide energy converters

    NASA Technical Reports Server (NTRS)

    Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

    1995-01-01

    Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

  14. Bidirectional buck boost converter

    DOEpatents

    Esser, A.A.M.

    1998-03-31

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero. 20 figs.

  15. Gallium phosphide energy converters

    NASA Astrophysics Data System (ADS)

    Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

    1995-10-01

    Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

  16. Gallium phosphide energy converters

    SciTech Connect

    Sims, P.E.; Dinetta, L.C.; Goetz, M.A.

    1995-10-01

    Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp {minus}17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

  17. An improved design of a dc-dc converter using an integrated magnetic component

    Microsoft Academic Search

    Aiman KERIM; Jean Paul FERRIEUX; James ROUDET; Stéphane CATELLANI; H. Benqassmi

    2008-01-01

    This paper presents a detailed analysis of an integrated magnetic structure. A generalized analytical designing formula of an integrated magnetic component is introduced. An improved numerical method is applied to estimate the proximity losses due to currents waveforms in an integrated magnetic half-bridge dc\\/dc converter, which are not sinusoidal. This method is based on the homogenizing of the electric conductors

  18. On the leading leg transition of phase-shifted ZVS-FB converters

    Microsoft Academic Search

    Song-Yi Lin; Chern-Lin Chen

    1998-01-01

    The primary current drop during the leading leg transition of phase-shifted zero-voltage-switching full-bridge (ZVS-FB) power converters is investigated. It is shown that this phenomenon is affected by the junction capacitance of rectifier diodes and transformer winding capacitance

  19. 500-W zero-voltage-switched full-bridge two-quadrant power modulator

    Microsoft Academic Search

    George K. Schoneman

    1993-01-01

    A zero-voltage-switched full-bridge regulator, with a switch frequency of 500 kHz, converts a 270 VDC input to an output voltage that is modulated between 22.5 volts and less than one volt. The small-signal reference-to-output bandwidth is greater than 60 kHz. Synchronous rectification allows the converter to source and sink output current

  20. Accurate Small-Signal Model for the Digital Control of an Automotive Bidirectional Dual Active Bridge

    Microsoft Academic Search

    Florian Krismer; Johann W. Kolar

    2009-01-01

    The derivation of an accurate small-signal model for a galvanically isolated, bidirectional dc-dc converter and the implementation of a corresponding controller on a DSP as well as key methods and functions required for the digital implementation are detailed in this paper. The investigated dc-dc converter, an automotive dual active bridge (DAB) system, enables power transfer between a low-voltage port (ranging

  1. Unusually Stable Pyrazolate-Bridged Dialuminum Complexes Containing Bridging Methyl Groups

    E-print Network

    Schlegel, H. Bernhard

    Unusually Stable Pyrazolate-Bridged Dialuminum Complexes Containing Bridging Methyl Groups Zhengkun pyrazoles with excess trimethylaluminum. The bridging methyl groups in these complexes are more stable than

  2. Efficient Power Converters for PV Arrays : Scalable Submodule Power Conversion for Utility-Scale Photovoltaics

    SciTech Connect

    None

    2012-02-23

    Solar ADEPT Project: SolarBridge is developing a new power conversion technique to improve the energy output of PV power plants. This new technique is specifically aimed at large plants where many solar panels are connected together. SolarBridge is correcting for the inefficiencies that occur when two solar panels that encounter different amounts of sun are connected together. In most conventional PV system, the weakest panel limits the energy production of the entire system. That’s because all of the energy collected by the PV system feeds into a single collection point where a central inverter then converts it into useable energy for the grid. SolarBridge has found a more efficient and cost-effective way to convert solar energy, correcting these power differences before they reach the grid.

  3. Electrical Actuation Technology Bridging

    NASA Technical Reports Server (NTRS)

    Hammond, Monica (compiler); Sharkey, John (compiler)

    1993-01-01

    This document contains the proceedings of the NASA Electrical Actuation Technology Bridging (ELA-TB) Workshop held in Huntsville, Alabama, September 29-October 1, 1992. The workshop was sponsored by the NASA Office of Space Systems Development and Marshall Space Flight Center (MSFC). The workshop addressed key technologies bridging the entire field of electrical actuation including systems methodology, control electronics, power source systems, reliability, maintainability, and vehicle health management with special emphasis on thrust vector control (TVC) applications on NASA launch vehicles. Speakers were drawn primarily from industry with participation from universities and government. In addition, prototype hardware demonstrations were held at the MSFC Propulsion Laboratory each afternoon. Splinter sessions held on the final day afforded the opportunity to discuss key issues and to provide overall recommendations. Presentations are included in this document.

  4. Rapid bridge deck replacement 

    E-print Network

    Osegueda, Roberto Alejandro

    1983-01-01

    , California . . . Maryland State Highway Administration-Federal Highway Administration Summary . Objectives of Study Scope of Study 2 EXPERIMENTAL WORK General 13 13 17 20 22 22 24 Selection of Prototype Bridge Model Design Design of Model... Distribution . . Comparison of Shear Stress Distribution Comparison of Midspan Deflections Comparison of Full Composite Test Results to Prototype . Flexural Strains 156 156 159 159 161 161 166 168 173 173 Deflections Discussion of Slip Di...

  5. BRIDGE Other Resources

    NSDL National Science Digital Library

    Bridge Ocean Resources provide access to ocean sciences educational materials with particular emphasis on K-12 audiences. The collection emphasizes biological oceanography, aquaria, research institutions, career information, student opportunities and announcements. There is a strong focus on research data and its use in teaching. The collection provides educators with a source of accurate and useful information on global, national, and regional ocean science topics, and gives researchers a contact point for educational outreach.

  6. Electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L. (inventor)

    1973-01-01

    Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

  7. Tunnel-diode converter analysis

    Microsoft Academic Search

    C. S. Kim

    1961-01-01

    An analysis of tunnel-diode converters is presented for two different conditions of operation. In the first, the converter is self-oscillating; in the second, the local oscillator (LO) voltage is provided from an external source. Two classes of self-oscillating converters are presented. The first operates on the fundamental of the oscillation frequency and the other operates on the second harmonic. Assuming

  8. The active-bridge oscillator

    SciTech Connect

    Wessendorf, K.O.

    1998-07-01

    This paper describes the Active-Bridge Oscillator (ABO), a new concept in high-stability oscillator design. The ABO is ab ridge-type oscillator design that is easly to design and overcomes many of the operational and design difficulties associated with standard bridge oscillator designs. The ABO will oscillate with a very stable output amplitude over a wide range of operating conditions without the use of an automatic-level-control (ALC). A standard bridge oscillator design requires an ALC to maintain the desired amplitude of oscillation. for this and other reasons, bridge oscilaltors are not used in mainstream designs. Bridge oscillators are generally relegated to relatively low-volume, high-performance applications. The Colpitts and Pierce designs are the most popular oscillators but are typically less stable than a bridge-type oscillator.

  9. Foundation Depth for Bridge Piers

    NASA Astrophysics Data System (ADS)

    Veerappadevaru, G.; Gangadharaiah, T.; Jagadeesh, T. R.

    2013-09-01

    The safety of bridge piers built in rivers having the bed is one of the prime aspects in the study of scouring process around bridge piers. The stability of bridge piers depends on the depth of foundation provided below maximum scour level. The stability analysis of bridge piers is carried based on moment of forces acting on the caisson pier when the pier slides and tilts slightly in downstream from its position. The experiments are conducted for three pier shapes on two sediment beds and for different flow conditions. The curves indicating the stability limits are compared with Lacey's recommendations which are used in present day practice in India. The analysis presented here indicates that the Lacey's recommendation for railway bridges is safe and for some cases of the road bridges depends on grip length, angle of tilt and weight of caisson.

  10. Tacoma Narrows Bridge: Extreme History

    NSDL National Science Digital Library

    Stretching across the southern portion of Puget Sound, the elegant Tacoma Narrows bridge is considered one of the finest suspension bridges in the United States. The current bridge is the second on the site, as it was constructed in 1950 to serve as a replacement to the famous "Galloping Gertie" bridge, which collapsed in a windstorm in the fall of 1940. Currently, the Washington State Department of Transportation is building a bridge to replace the existing structure, and it is anticipated that it will be completed in 2007. This site offers a host of materials on all three structures, including ample information on the construction of the bridges and their aesthetic appeal. Along with these materials, the site also provides a glossary of related terms, Weird Facts, and some information about the dog "Tubby", who perished when "Galloping Gertie" collapsed on that fateful fall day back in 1940.

  11. Self-Driven Synchronous Rectification Scheme for Wide Range Application of DC\\/DC Converters with Symmetrically Driven Transformers

    Microsoft Academic Search

    Ting Qian; Wei Song; Brad Lehman

    2006-01-01

    Synchronous rectifiers are widely used in low voltage and high current DC\\/DC converters to reduce conduction power loss. For popular and reliable topologies, such as half-bridge, push-pull and phase-shifted full-bridge, the application of self-driven synchronous rectification has design challenges due to the existence of dead times. Existing solutions are not suitable for wide input voltage ranges. This paper presents a

  12. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  13. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  14. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  15. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  16. 49 CFR 236.312 - Movable bridge, interlocking of signal appliances with bridge devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...false Movable bridge, interlocking of signal appliances with bridge devices. 236...INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES...312 Movable bridge, interlocking of signal appliances with bridge devices....

  17. 75 FR 62181 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-07

    ...Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY...Federal Register a report describing construction materials used in new Federal-aid bridge construction and bridge rehabilitation...

  18. 76 FR 55160 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ...Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY...Federal Register a report describing construction materials used in new Federal-aid bridge construction and bridge rehabilitation...

  19. Ion bridges in microfluidic systems

    Microsoft Academic Search

    Taek Dong Chung; Hee Chan Kim

    2009-01-01

    Recently many microfluidic systems are increasingly equipped with functional units for ionic controls for various applications.\\u000a In this review article, we define an ion bridge as a structure that controls current or distribution of ions in a microfluidic system, and summarize the ion bridges in the\\u000a literature in terms of characteristics, fabrication methods, advantages and disadvantages. The ion bridges play

  20. BRIDGE: Briefings on Development & Gender

    NSDL National Science Digital Library

    BRIDGE (briefings on development and gender) is an information service provided by the Institute of Development Studies (IDS) at the University of Sussex. BRIDGE supplies development agencies with briefings that "present state of the art research findings, review current policy debates, synthesize best practice, and evaluate strategies for translating gender policies into practice." This site includes full-text BRIDGE publications, a bibliographic database, and links to other gender and development resources.

  1. Morphological aspects of myocardial bridges

    PubMed Central

    Lujinovi?, Almira; Kulenovi?, Amela; Kapur, Eldan; Gojak, Refet

    2013-01-01

    Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the “tunnel” segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. The studied material contained 30 human hearts received from the Department of Anatomy. The hearts were preserved 3 to 5 days in 10% formalin solution. Thereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. The angle between the myocardial bridge fibre axis and other axis of the crossed blood vessel was measured by a goniometer. The presence of the bridges was confirmed in 53.33% of the researched material, most frequently (43.33%) above the anterior interventricular branch. The mean length of the bridges was 14.64±9.03 mm and the mean thickness was 1.23±1.32 mm. Myocardial bridge fibres pass over the descending blood vessel at the angle of 10-90 degrees. The results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the difference is not significant in relation to bridges located on other branches. The results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel. PMID:24289755

  2. Extended bridge algorithms for large networks

    Microsoft Academic Search

    W. D. Sincoskie; C. J. Cotton

    1988-01-01

    A network bridge is a device that operates at the ISO data link level and routes packets across extended networks, commonly composed of multiple local area networks (LANs) and bridges. A set of algorithms that greatly extends the application of the network bridge is presented. This multitree bridge algorithm allows networks of arbitrary topology and capacity to use bridge routing.

  3. Strengthening of Steel Girder Bridges Using FRP

    Microsoft Academic Search

    Brent M. Phares; Terry J. Wipf; F. Wayne Klaiber; Ahmad Abu-Hawash; Yoon-Si Lee

    This paper documents two projects funded through the Federal Highway Administration's Innovative Bridge Research and Construction (IBRC) program. The IBRC program was developed to assist bridge owners in applying emerging technologies in bridge engineering. In these projects, the Iowa Department of Transportation employed techniques for strengthening steel girder bridges using carbon fiber reinforced polymers (CFRP). Two bridges were strengthened using

  4. Microfabricated multijunction thermal converters

    NASA Astrophysics Data System (ADS)

    Wunsch, Thomas Franzen

    2001-12-01

    In order to develop improved standards for the measurement of ac voltages and currents, a new thin-film fabrication technique for the multijunction thermal converter has been developed. The ability of a thermal converter to relate an rms ac voltage or current to a dc value is characterized by a quantity called `ac-dc difference' that is ideally zero. The best devices produced using the new techniques have ac-dc differences below 1 × 10-6 in the range of frequencies from 20 Hz to 10 kHz and below 7.5 × 10-6 in the range of frequencies from 20 kHz to 300 kHz. This is a reduction of two orders of magnitude in the lower frequency range and one order of magnitude in the higher frequency range over devices produced at the National Institute of Standards and Technology in 1996. The performance achieved is competitive with the best techniques in the world for ac measurements and additional evaluation is therefore warranted to determine the suitability of the devices for use as national standards that form the legal basis for traceable rms voltage measurements of time varying waveforms in the United States. The construction of the new devices is based on thin-film fabrication of a heated wire supported by a thermally isolated thin-film membrane. The membrane is produced utilizing a reactive ion plasma etch. A photoresist lift- off technique is used to pattern the metal thin-film layers that form the heater and the multijunction thermocouple circuit. The etching and lift-off allow the device to be produced without wet chemical etches that are time consuming and impede the investigation of structures with differing materials. These techniques result in an approach to fabrication that is simple, inexpensive, and free from the manual construction techniques used in the fabrication of conventional single and multijunction thermoelements. Thermal, thermoelectric, and electrical models have been developed to facilitate designs that reduce the low- frequency error. At high frequencies, from 300 kHz to 1 MHz, the performance of the device is degraded by a capacitive coupling effect that produces an ac-dc difference of approximately -90 × 10-6 at 1 MHz. A model is developed that explains this behavior. The model shows that an improvement in performance in the high-frequency range is possible through the use of very high or very low resistivity silicon substrates.

  5. A novel soft-switching high-frequency transformer isolated three phase AC-to-DC converter with low harmonic distortion

    Microsoft Academic Search

    F. Hamdad; A. K. S. Bhat

    1998-01-01

    A high-frequency transformer isolated, fixed-frequency, 3-? single-stage AC-to-DC converter using a boost-integrated bridge converter is proposed. This converter enjoys natural power factor correction with low line current harmonic distortion and symmetric high frequency voltage and current waveforms while ensuring zero voltage switching for all the switches for a wide variation in load and line voltage. Various operating modes of the

  6. Bridging The Inferential Gap

    PubMed Central

    Stewart, Walter F.; Shah, Nirav R.; Selna, Mark J.; Paulus, Ronald A.; Walker, James M.

    2009-01-01

    Most clinical decisions involve bridging the inferential gap: Clinicians are required to “fill in” where they lack knowledge or where no knowledge yet exists. In this context we consider how the inferential gap is a product, in part, of how knowledge is created, the limits to gaining access to such knowledge, and the variable ways in which knowledge is translated into decisions. We consider how electronic health records (EHRs) will help narrow this gap by accelerating the creation of evidence relevant to everyday practice needs and facilitating real-time use of knowledge in practice. PMID:17259202

  7. Strengthen a Paper Bridge

    NSDL National Science Digital Library

    Twin Cities Public Television, Inc.

    2006-01-01

    In this quick activity (page 1 of the PDF), learners will test how many pennies a flat paper index card bridging the gap between two stacks of books is able to support. Then, learners alter the structure of the same card by folding it accordion-style and retest by again stacking pennies on top. Learners look for a relationship between the number of folds and the number of pennies the card can hold by creating a scatter plot. Relates to the linked video, DragonflyTV: Tug O’ War.

  8. Rapid bridge deck replacement

    E-print Network

    Osegueda, Roberto Alejandro

    1983-01-01

    at 24 Hours 93 19 Tensile Strength of Epoxy Mortar of Connections at 24 Hours 94 20 Initial Tangent Moduli of Epoxy Mortar of Connections 21 Theoretical Correlation Factor of Flexural Strain 98 Gages 103 22 Average Percent Error of Shear Strain... replacement time as well as traffic interference. An experimental study consisting of static load tests on a 1/3 scale model of a 60-ft-long steel I-girder bridge with precast concrete panels connected with epoxy mortar and shear connectors to accomplish...

  9. Bridging the Watershed

    NSDL National Science Digital Library

    Bridging the Watershed is a partnership between Washington DC area schools and the National Park Service that uses the Potomac River and Chesapeake Bay watersheds as "learning laboratories." The Students section of this site has some great interactive activities that help students learn how to identify plants and ecosystems, determine stream health based on macroinvertebrate identification, and understand the perils of migratory fish. This is a great Web site with a broad range of information suitable to a variety of different age levels and interests, yet with enough detail to make each section stand alone.

  10. Bridging biometrics and forensics

    NASA Astrophysics Data System (ADS)

    Yan, Yanjun; Osadciw, Lisa Ann

    2008-02-01

    This paper is a survey on biometrics and forensics, especially on the techniques and applications of face recognition in forensics. This paper describes the differences and connections between biometrics and forensics, and bridges each other by formulating the conditions when biometrics can be applied in forensics. Under these conditions, face recognition, as a non-intrusive and non-contact biometrics, is discussed in detail as an illustration of applying biometrics in forensics. The discussion on face recognition covers different approaches, feature extractions, and decision procedures. The advantages and limitations of biometrics in forensic applications are also addressed.

  11. Vibration-Based Physical Parameter Identification of Bridge Structures under Traffic Excitation

    Microsoft Academic Search

    Wu Zi-yan; Liu Shu-kui; He Yin; Yang Hai-feng

    2009-01-01

    A new compound method of physical parameters identification of bridge structures under traffic excitation is presented in this paper. Employing the dynamic nodal loading (DNL) approach, which could consider the dynamic response due to the road irregularities and vehicle inertia effect of a vehicle-structure system, the moving vehicle load could be converted into the transient load on each node in

  12. Indian Converts Collection

    NSDL National Science Digital Library

    First published in 1727, the remarkable book "Indian Converts, or Some account of the lives and dying speeches of a considerable number of the Christianized Indians of Martha's Vineyard" is now available in full online. Written by Experience Mayhew, the book provides remarkable insights into the lives and culture of four generations of Native Americans in colonial America. This digitized version was created at Reed College, and visitors can look through all four sections of the work, which include "Indian Ministers" and "Pious Children." Throughout the work, Mayhew details the books that different age groups were reading, provides insights into early New England pedagogy and childrearing practices, and also describes each individual in terms of their own genealogy and personal history. The truly fantastic thing about the site is that it also contains an archive with over 600 images and documents that further contextualize the work. Also, the site contains study guides designed for classroom use that cover artifact analysis, genealogy, and reading gravestones.

  13. Proposed electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L.

    1973-01-01

    Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

  14. PWM Converter Power Density Barriers

    Microsoft Academic Search

    J. W. Kolar; U. Drofenik; J. Biela; M. L. Heldwein; H. Ertl; T. Friedli; S. D. Round

    2007-01-01

    Power density of power electronic converters in different applications has roughly doubled every 10 years since 1970. Behind this trajectory was the continuous advancement of power semiconductor device technology allowing an increase of converter switching frequencies by a factor of 10 every decade. However, today's cooling concepts, and passive components and wire bond interconnection technologies could be major barriers for

  15. Matrix converters: a technology review

    Microsoft Academic Search

    Patrick W. Wheeler; José Rodríguez; Jon C. Clare; Lee Empringham; Alejandro Weinstein

    2002-01-01

    The matrix converter is an array of controlled semiconductor switches that connects directly the three-phase source to the three-phase load. This converter has several attractive features that have been investigated in the last two decades. In the last few years, an increase in research work has been observed, bringing this topology closer to the industrial application. This paper presents the

  16. Function: Cliplus:-`convert/dwedge_to_wedge`, Cliplus:-`convert/dwedge_to_wedge` -converting between wedge and dotted wedge

    E-print Network

    Ablamowicz, Rafal

    Function: Cliplus:-`convert/dwedge_to_wedge`, Cliplus:-`convert/dwedge_to_wedge` - converting between wedge and dotted wedge Calling Sequence: c1 := convert(p1,wedge_to_dwedge,F) c2 := convert(p2 Grassmann wedge monomials) · F, FT - argument of type name, symbol, matrix, array, or `&*`(numeric,{name,symbol,matrix

  17. Trigenomic Bridges for Brassica Improvement

    Microsoft Academic Search

    Sheng Chen; Matthew N. Nelson; Anne-Marie Chèvre; Eric Jenczewski; Zaiyun Li; Annaliese S. Mason; Jinling Meng; Julie A. Plummer; Aneeta Pradhan; Kadambot H. M. Siddique; Rod J. Snowdon; Guijun Yan; Weijun Zhou; Wallace A. Cowling

    2011-01-01

    We introduce and review Brassica crop improvement via trigenomic bridges. Six economically important Brassica species share three major genomes (A, B, and C), which are arranged in diploid (AA, BB, and CC) and allotetraploid (AABB, AACC, and BBCC) species in the classical triangle of U. Trigenomic bridges are Brassica interspecific hybrid plants that contain the three genomes in various combinations,

  18. Bridges to computer architecture education

    Microsoft Academic Search

    Peter Marwedel; Birgit Sirocic

    2004-01-01

    Bridging the gap between the student's current knowledge and the technical details of computer systems is frequently required for the education of undergraduate students or students with a lack of previous technical knowledge. In this paper we will describe how to build bridges by the combination of introducing Flash-animations and the educational units of the RaVi system. In a first

  19. A natural ZVS high-power bi-directional DC-DC converter with minimum number of devices

    Microsoft Academic Search

    Hui Li; Fang Z. Peng; Jack S. Lawler

    2001-01-01

    This paper introduces a new bi-directional, isolated DC-to-DC converter. A typical application for this converter can be found in the auxiliary power supply of hybrid electric vehicles. A dual half-bridge topology has been developed to implement the required power rating using the minimum number of devices. Unified zero-voltage-switching was achieved in either direction of power flow with neither a voltage-clamping

  20. Duty Cycle Exchanging Control for Input-Series-Output-Series Connected Two PS-FB DC-DC Converters

    Microsoft Academic Search

    Deshang Sha; Kai Deng; XiaoZhong Liao

    2012-01-01

    Input-series-output-series (ISOS) connected dc-dc converters enable low voltage rating switches to be used in high voltage input and high voltage output applications needing electrical isolation. In order for ISOS connected two phase-shifted-full-bridge (PS-FB) dc-dc converters to achieve input voltage sharing (IVS) and output voltage sharing (OVS), duty cycle exchanging control is implemented by exchanging their duty cycles. Based on small-signal

  1. A High Frequency-Link Bidirectional DC-DC Converter for Super Capacitor-Based Automotive Auxiliary Electric Power Systems

    Microsoft Academic Search

    Tomokazu Mishima; Eiji Hiraki; Mutsuo Nakaoka

    2009-01-01

    This paper presents a bidirectional DC-DC converter suitable for low-voltage super capacitor-based electric energy storage systems. The DC-DC converter presented here consists of a full-bridge circuit and a current-fed push-pull circuit with a high frequency (HF) transformer-link. In order to reduce the device-conduction losses due to the large current of the super capacitor as well as unnecessary ringing, synchronous rectification

  2. Power-quality improvements in vector-controlled induction motor drive employing pulse multiplication in AC-DC converters

    Microsoft Academic Search

    Bhim Singh; G. Bhuvaneswari; Vipin Garg

    2006-01-01

    This paper deals with the pulse doubling in a 12-pulse ac-dc converter for improving power quality in vector-controlled induction motor drives (VCIMDs). The design of proposed magnetics shows the flexibility in varying the voltage ratio of the autotransformer for making it suitable for retrofit applications, where presently a six-pulse diode bridge rectifier is being used. The proposed ac-dc converter is

  3. Analysis and design for reducing voltage stress in output rectifier of LFLRV SIV DC-DC converter

    Microsoft Academic Search

    Diao Lijun; Chen Jie; Lin Wenli; Liu Zhigang

    2009-01-01

    This paper presents a full-bridge full-wave DC-DC converter used in 35 kVA power grade auxiliary static inverter (SIV) of first low-floor light rail vehicle (LFLRV) in China, where reducing voltage stress in output rectifier diodes is so important for the converter reliability. DC-bias function of high frequency transformer is analyzed and a sensorless digital dc-bias control method by DSP and

  4. A novel soft-switching DC-DC converter with wide ZVS-range and reduced filter requirement

    Microsoft Academic Search

    Rajapandian Ayyanar; Ned Mohan

    1999-01-01

    A novel soft-switching DC-DC converter capable of achieving high power density and high efficiency is proposed. It has the following features compared to the conventional phase-modulated full-bridge converters (PMC): (i) same number (four) of switches with identical total switch VA ratings; (ii) zero-voltage-switching down to no-load, hence lower EMI; (iii) lower conduction losses; and (iv) smaller overall magnetics requirement. The

  5. Control Design of a Three-Phase Matrix-Converter-Based AC–AC Mobile Utility Power Supply

    Microsoft Academic Search

    Pericle Zanchetta; Patrick W. Wheeler; Jon C. Clare; Michael Bland; Lee Empringham; Dimosthenis Katsis

    2008-01-01

    This paper describes the control analysis and design of an ac-to-ac three-phase mobile utility power supply using a matrix converter capable of high-quality 50-, 60-, and 400-Hz output voltage and reduced input harmonic distortion. Instead of the traditional structure employing a diode bridge rectifier, a dc link and a pulsewidth-modulated inverter, a three-phase-to-three-phase direct ac-ac (matrix) converter has been used

  6. Construction Technologies: Construct the Strongest Bridge

    NSDL National Science Digital Library

    Joy Trahan-Liptak

    2013-01-01

    Learners work in pairs to create three simple types of bridges, a beam bridge, an arch bridge, and a suspension bridge. They will observe how the bridges work under load and discover why engineers use different types of bridges for different places. Learners are introduced to the parts needed to build a bridge, and what they are for. Resource contains detailed diagrams and photos to assist in bridge building. Investigating questions allow learners to discuss the activity and apply their understanding to their world. Activity time can be split across multiple meetings.

  7. CRIME BULLETIN INCIDENT: Catalytic Converter Thefts

    E-print Network

    Barrett, Jeffrey A.

    CRIME BULLETIN C R I M E INCIDENT: Catalytic Converter Thefts DATE/TIME: 2/20/2013-2/27/2013, Various Times CONTACT: UCIPD Corporal B. Green (949) 824-5223 Catalytic converter Catalytic converter converters were stolen from various locations on the UC Irvine campus. The catalytic converters came from

  8. A New High Frequency Linked Soft-Switching PWM DC-DC Converter with High and Low Side DC Rail Active Edge Resonant Snubbers for High Performance Arc Welder

    Microsoft Academic Search

    K. Fathy; T. Doi; K. Morimoto; Hyun Woo Lee; M. Nakaoka

    2006-01-01

    This paper presents a new circuit topology of active edge resonant snubbers assisted half-bridge soft switching PWM inverter type dc-dc high power converter for DC bus feeding power plants. The proposed dc-dc power converter is composed of typical voltage source fed half-bridge high frequency PWM inverter with a high frequency transformer planar link in addition to dc busline side power

  9. Bridging the Watershed

    NSDL National Science Digital Library

    Bridging the Watershed (BTW) is an outreach program of the Alice Ferguson Foundation in partnership with the National Park Service and area schools. It promotes national parks as learning laboratories and provides a model that can be replicated in other parks and watersheds. The program is based in the Washington, D.C. metropolitan area. BTW partners share a fundamental goal to educate the public about the Potomac River and Chesapeake Bay watersheds in order to heighten awareness and develop stewardship for these resources. Science curriculum modules have been developed for high school students studying Earth science, chemistry, and the life sciences. Each module is composed of performance-based activities in which students examine and analyze the health of their watershed by applying science, math, problem-solving and action skills. Students gather authentic data to assess and problem solve real-world issues in the parks and watershed.

  10. Stanford: The Bridge Project

    NSDL National Science Digital Library

    Stanford University's Bridge Project: Strengthening K-16 Transition Policies emphasizes that "reforms affecting K-12 and higher education must occur across systems in order to achieve the desired outcomes." Their approach is to improve opportunities for all students to enter and succeed in higher education by strengthening the alignment between higher education admissions-related requirements and K-12 curriculum frameworks, standards, and assessments. They conduct research that is meant to inform educational institutions and federal, state, and local agencies through descriptive analysis of the policies, identification of "disjunctures that exist in the current policy environment," and recommendations for improving the current system. Details about this program as well as their policy reports and briefs are available from their website.

  11. Bridges to Structure

    NSDL National Science Digital Library

    Peter Woodruff (Champlain-St. Lambert College; )

    2004-06-12

    This project's goals are to investigate structural components at a variety of levels: molecularly, cellularlly (histologically),phylogenetically, organismally, etc. Traditionally the stuctural classes at many institutions have used primarily dissection and histology for comparison of different vertebrate classes. In this project, we began to develop exercises at the molecular level using gemonmic and proteomic information to form phylogenetic trees, started a chart of materials available at NCBI for use in comparison (phylogentically and visually) of characteristic proteins from specific organ systems, and initiated thinking about a project to start a pictorial archive of dissection activities and histological meassurements. With the signifcant movement to integrate more material within biology and other areas of science and mathematics, building bridges (exercises) amongst a number of levels seems relevant. In addition, adding more open-ended projects with greater manipulation of data and mathematical manipulation in these courses is very desirable.

  12. The Bridges Organization

    NSDL National Science Digital Library

    The connection between art and mathematics is well known, and the Bridges Organization has been bringing together these two worlds since 1998. The group started in Kansas, and since then they have traveled to cities in North America and Europe. On this site, visitors can learn about their past conferences, and view some of their galleries of images. The "Virtual Museum" area is a real treat, and visitors can look at spherical paintings, geometric sculptures, and algorithmic visual art. Moving on, the "Educational Resource Center" area features links of interest to educators, including sites dedicated to teaching mathematical thinking through origami and such. The site is rounded out by past conference reports and information about their leadership.

  13. Burning trees and bridges

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.

    1990-01-01

    Most burning of biomass is the result of human activity, and on a global scale it is increasing. Tropospheric concentrations of CO2, CO, CH4, non-methane hydrocarbons, and ozone are all increasing with time; global biomass burning may make an important contribution to this increase and thus to potential global climate change. The nitrogen cycle also can have important climatic effects. Nitrous oxide put into the atmosphere by biomass burning is a greenhouse gas 250 times more powerful (molecule for molecule) than carbon dioxide. Nitric oxide, as well as being a photochemical precursor of ozone, a major pollutant in the troposphere, produces nitric acid, the fastest-growing component of acid rain. Hence, the new bridge in the nitrogen cycle is of more than mere technical interest.

  14. Coherence convertibility for mixed states

    E-print Network

    Xiaofei Qi; Zhaofang Bai; Shuanping Du

    2015-05-27

    In this paper, by providing a class of coherence measures in finite dimensional systems, a sufficient and necessary condition for the existence of coherence transformations that convert one probability distribution of any pure states into another one is obtained.

  15. Wind/water energy converter

    NASA Technical Reports Server (NTRS)

    Paulkovich, J.

    1979-01-01

    Device will convert wind, water, tidal or wave energy into electrical or mechanical energy. Is comprised of windmill-like paddles or blades synchronously geared to orient themselves to wind direction for optimum energy extraction.

  16. Liquid-Bridge Breaking Limits

    NASA Astrophysics Data System (ADS)

    Macner, Ashley; Steen, Paul

    2011-11-01

    Wet adhesion by liquid bridges in large arrays shows promise for use in lightweight, controllable on-demand devices. Applications include grab/release of wafer substrates, transport of micron-sized tiles for use in 3D printing and micro-dosing of personalized pharmaceutical drugs. By wetting and spreading, a drop can form a bridge and thereby ``grab'' a nearby solid substrate. By volume decrease or extension, the bridge can break. The breaking limit corresponds to bridge instability which can be predicted, knowing the static mechanical response of the bridge. Mechanical behaviors include force-volume (FV), pressure-volume (pV) and force-length (FL) responses. Instability crucially depends on the mode of failure - failure under constant-force or constant length are typical cases. We study single bridge equilibria for their breaking limits. FV diagrams for the pin-pin equal and pin-pin unequal radii boundary conditions for different bridge heights are measured in the laboratory. The FL response in the case of pin-pin equal radii is also measured. Results are compared to predictions of static theory. Static results are then used to compare to dynamical sequences where volume is driven quasistatically by syringe or an electro-osmotic pump. As the breaking limit is approached, the shape deformation accelerates leading to non-equilibrium shapes not captured by the static analysis.

  17. Radiation tolerant power converter controls

    NASA Astrophysics Data System (ADS)

    Todd, B.; Dinius, A.; King, Q.; Uznanski, S.

    2012-11-01

    The Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is the world's most powerful particle collider. The LHC has several thousand magnets, both warm and super-conducting, which are supplied with current by power converters. Each converter is controlled by a purpose-built electronic module called a Function Generator Controller (FGC). The FGC allows remote control of the power converter and forms the central part of a closed-loop control system where the power converter voltage is set, based on the converter output current and magnet-circuit characteristics. Some power converters and FGCs are located in areas which are exposed to beam-induced radiation. There are numerous radiation induced effects, some of which lead to a loss of control of the power converter, having a direct impact upon the accelerator's availability. Following the first long shut down (LS1), the LHC will be able to run with higher intensity beams and higher beam energy. This is expected to lead to significantly increased radiation induced effects in materials close to the accelerator, including the FGC. Recent radiation tests indicate that the current FGC would not be sufficiently reliable. A so-called FGClite is being designed to work reliably in the radiation environment in the post-LS1 era. This paper outlines the concepts of power converter controls for machines such as the LHC, introduces the risks related to radiation and a radiation tolerant project flow. The FGClite is then described, with its key concepts and challenges: aiming for high reliability in a radiation field.

  18. HIGH EFFICIENCY AUXILIARY POWER CONVERTERS

    Microsoft Academic Search

    Geoff Walker

    The auxiliary load DC-DC converters of the Sunshark solar car have never been examined. An analysis of the current design reveals it is complicated, and inefficient. Some simple measures to greatly improve the efficiency are present which will achieve an overall worthwhile power saving. Two switch-mode power supply DC-DC converter designs are presented. One is a constant current supply for

  19. AMTEC cells challenge energy converters

    Microsoft Academic Search

    Henry Oman

    1999-01-01

    Sodium-base alkali-metal-thermal-to-electric conversion (AMTEC) cells have been receiving attention. Recently they were selected for the next generation deep-space missions, which need a converter that makes electricity from radioisotope heat. The AMTEC cell, being an electrochemical converter of heat to electricity, has no moving parts and is not limited to Carnot-cycle efficiency. However, its heat source and sink have to be

  20. Chesapeake Bay Bridge-Tunnel

    NSDL National Science Digital Library

    2002-01-01

    The Chesapeake Bay Bridge-Tunnel is a 20 mile long series of bridges and tunnels that connect Virginia Beach/Norfolk to Virginia's Eastern Shore. The project is an engineering marvel; besides supporting vehicular traffic, the tunnels allow sea-going vessels passage into and out of the bay. A great deal of information is given on the project's home page, including a map of the surrounding area, historical perspectives, interesting facts, tourist attractions, and frequently asked questions. There are also a few pictures scattered throughout the site that show the enormity of the bridge-tunnel.

  1. Non-Seismology Seismology: Using QuakeCatchers to Analyze the Frequency of Bridge Vibrations

    NASA Astrophysics Data System (ADS)

    Courtier, A. M.; Constantin, C.; Wilson, C. F.

    2013-12-01

    We conducted an experiment to test the feasibility of measuring seismic waves generated by traffic near James Madison University. We used QuakeCatcher seismometers (originally designed for passive seismic measurement) to measure vibrations associated with traffic on a wooden bridge as well as a nearby concrete bridge. This experiment was a signal processing exercise for a student research project and did not draw any conclusions regarding bridge safety or security. The experiment consisted of two temporary measurement stations comprised of a laptop computer and a QuakeCatcher - a small seismometer that plugs directly into the laptop via a USB cable. The QuakeCatcher was taped to the ground at the edge of the bridge to achieve good coupling, and vibrational events were triggered repeatedly with a control vehicle to accumulate a consistent dataset of the bridge response. For the wooden bridge, the resulting 'seismograms' were converted to Seismic Analysis Code (SAC) format and analyzed in MATLAB. The concrete bridge did not generate vibrations significant enough to trigger the recording mechanism on the QuakeCatchers. We will present an overview of the experimental design and frequency content of the traffic patterns, as well as a discussion of the instructional benefits of using the QuakeCatcher sensors in this non-traditional setting.

  2. Bridge Deck Deicing using Geothermal Heat Pumps

    Microsoft Academic Search

    JEFFREY D. SPITLER; MAHADEVAN RAMAMOORTHY

    Several research projects at Oklahoma State University have investigated bridge deck deicing systems that utilize a ground source heat pump system to provide heating. This paper describes simulation methodology; the design of a system planned for installation on a bridge deck near Weatherford, Oklahoma; and results from system simulations of the proposed bridge deck. System simulations of the bridge deck

  3. Post-earthquake Prioritization of Bridge Inspections

    E-print Network

    Eberhard, Marc O.

    considered, the percentage of bridges damaged correlated best with the spectral acceleration at a period of 0.3 s. Bridges constructed before the 1940s, movable bridges, and older trusses were particularlyPost-earthquake Prioritization of Bridge Inspections R. T. Ranf,a... M.EERI, M. O. Eberhard,b... M

  4. Bridges, Switches, Routers 1.1 Introduction

    E-print Network

    Varaiya, Pravin

    Chapter 1 Bridges, Switches, Routers 1.1 Introduction ¯ Packet vs circuit (and virtual circuit ¯ Packet processors--Bridges, Routers, ATM switches 1 #12;2 CHAPTER 1. BRIDGES, SWITCHES, ROUTERS Routing in an extended LAN. See Problem 2. #12;4 CHAPTER 1. BRIDGES, SWITCHES, ROUTERS Figure 1.3: LAN vs VLAN topology

  5. NEW ACTIVE LOAD VOLTAGE CLAMP FOR HF-LINK CONVERTERS Petar Ljusev and Michael A.E. Andersen

    E-print Network

    NEW ACTIVE LOAD VOLTAGE CLAMP FOR HF-LINK CONVERTERS Petar Ljusev and Michael A.E. Andersen Ørsted an alternative load current path during malfunctions of the secondary bidirectional bridge. The feasibility in both directions. This is posing some unique problems with the commutation of the load current between

  6. A unified modulation algorithm for voltage and current source inverters based on AC-AC matrix converter theory

    Microsoft Academic Search

    Donald Grahame Holmes

    1992-01-01

    A unified pulse width modulation (PWM) algorithm is presented that is derived from AC-AC matrix power converter theory. The algorithm can be used to implement either a voltage source or a current source inverter, using only conventional bridge topologies. The resultant modulation strategy produces minimal low-order AC harmonics, yet it is readily capable of being computed online in a single

  7. Pulse excitation of bolometer bridges

    NASA Technical Reports Server (NTRS)

    Rusk, S. J.

    1972-01-01

    Driving bolometer bridge by appropriately phased excitation pulses increases signal-to-noise ratio of bolometer sensor which operates on a chopped light beam. Method allows higher applied voltage than is possible by conventional ac or dc excitation.

  8. Earthquake Response of Suspension Bridges

    NASA Astrophysics Data System (ADS)

    Erdik, Mustafa; Apayd?n, Nurdan

    Suspension bridges represent critical nodes of major transportation systems. Bridge failure during strong earthquakes poses not only a threat of fatalities but causes a substantial interruption of emergency efforts. Although wind induced vibrations have historically been the primary concern in the design of suspension bridges, earthquake effects have also gained importance in recent decades. This study involves ambient vibration testing and sophisticated three-dimensional dynamic finite element analysis and earthquake performance assessment of Fatih Sultan Mehmet and suspension Bo?aziçi bridges in Istanbul under earthquake excitation. Nonlinear time history analysis of 3D finite-element models of Fatih Sultan Mehmet and Bo?aziçi suspension bridges included initial stresses in the cables, suspenders, and towers in equilibrium under dead load conditions. Multi-support scenario earthquake excitation was applied to the structure. Suspension bridges are complex 3-D structures that can exhibit a large number of closely spaced coupled modes of vibration. The large number of closely spaced modes, spatially different ground motion characteristics, and the potential for nonlinear behaviour complicate the seismic response of suspension bridges. Spatial variation of ground motion exhibits itself with different ground motions at supports due to the wave passage, incoherence and local site effects. The source of nonlinear behaviour is due to geometric nonlinearity and the presence of cables that can only carry tensile forces. The natural frequencies of vibration and the corresponding mode shapes in their dead load and live load configurations are determined. Displacement time histories and stresses at critical points of the bridges are computed and their earthquake performance under the action of scenario earthquake are estimated.

  9. Effect on engineer bridging equipment

    Microsoft Academic Search

    1954-01-01

    The purpose of Project 3.22, Operation UPSHOT-KNOTHOLE, was to indicate the vulnerability of Army prefabricated fixed bridging to atomic blast and to determine means to reduce the vulnerability. To accomplish this, two 100-ft Bailey bridge spans were erected such that one was exposed to Shot 9 and both were exposed to Shot 10 of the test series; and two single

  10. Bridges.org

    NSDL National Science Digital Library

    Bridges.org is "an international non-profit organisation that promotes the effective use of Information and communications technology (ICT) in the developing world to reduce poverty and improve people's lives." The focus of its work involves ICT-related policy analysis, but organization "also promote best practice in ground-level technology implementation through research and evaluations." It provides information and resources, support grassroots projects and other efforts, and advise decision-makers and the public on key issues. As members of the technology community, the organization brings "an entrepreneurial attitude" and an understanding of technology as well as its commitment to work with governments and the private sector to achieve the goal of "spanning the international digital divide." The website provides an overview of the "digital divide" and describes the organization's approach to addressing these issues. Policy reports, case studies and evaluation guidelines are posted on this website. The organization's current work includes a comparison study of open source and proprietary software, which is also described here.

  11. Structural Health Indices for Steel Truss Bridges

    Microsoft Academic Search

    Ryan Kent Giles; Robin Kim; Billie F. Spencer; M. Nathan; Anne M. Newmark; Lawrence A. Bergman; Carol K. Shield; Steven C. Sweeney

    \\u000a Steel bridges represent a significant portion of the nation’s aging bridge inventory. The United States Army’s inventory has\\u000a over two hundred steel bridges that are vital to the operation of nearly every Army Installation. The Army regularly inspects\\u000a their bridges to ensure the continued functionality of the bridges. However, current inspection techniques and schedules may\\u000a not be able to detect

  12. Practical Evaluations of a Novel Asymmetrical ZCS-PWM DC-DC Converter with High-Frequency Transformer-Link

    NASA Astrophysics Data System (ADS)

    Mishima, Tomokazu; Hiraki, Eiji; Nakaoka, Mutsuo

    This paper presents a novel Zero Current Switching (ZCS)-PWM controlled half-bridge DC-DC converter with High-Frequency (HF)-link. The newly-proposed soft switching DC-DC converter consists of a multi-resonant half-bridge HF-isolated inverter controlled by an asymmetrical PWM scheme and a center-tapped diode rectifier with a choke input filter. In order to attain the wide range of soft-commutation under the condition of constant switching frequency, the single Active Edge-Resonant Cell (AERC) that is composed of a lossless inductor and a switched resonant capacitor is originally employed for the half-bridge inverter arm, providing and assisting ZCS operations in the switching power devices. The ZCS-PWMDC-DC converter treated here is evaluated in experiments using the 800 W-55 kHz prototype. The practical effectiveness of the proposed soft switching DC-DC converter is actually demonstrated and discussed with the experimental results under open loop and closed loop configurations. Finally, the feasibility of the DC-DC converter topology is discussed from the view points of the high efficiency and high power density.

  13. Analysis and design of PPFHB bidirectional DC-DC converter with coupled inductors

    Microsoft Academic Search

    Zhe Zhang; Ole C. Thomsen; Michael A. E. Andersen

    2009-01-01

    In this paper, a novel push-pull-forward half-bridge (PPFHB) bi-directional DC-DC converter with coupled inductors is proposed. All switches can operate under zero-voltage-switching (ZVS). The operation principle with phase-shift modulation scheme, characteristics of coupled inductors, the steady state relationship and small-signal model are analyzed. The voltage controller based on the small-signal model in z-domain is designed. A 500 W prototype controlled

  14. An Isolated Bidirectional DC-DC Soft Switching Converter for Super Capacitor Based Energy Storage Systems

    Microsoft Academic Search

    Eiji Hiraki; Koji Yamamoto; T. Mishima

    2007-01-01

    In recent years, power electronic energy storage systems using super capacitor bank have been widely studied and developed for the electronic vehicles. In this paper, a full-bridge\\/centertapped push-pull circuit with active clamp-based soft switching bidirectional DC-DC converter and its control method are presented and discussed. From the results of basic experimental demonstration, the proposed system is able to perform adequate

  15. A push-pull converter based bidirectional DC-DC interface for energy storage systems

    Microsoft Academic Search

    Eiji Hiraki; Kazumasa Hirao; Toshihiko Tanaka; Tomokazu Mishima

    2009-01-01

    In recent years, power electronic energy storage systems using super capacitor bank have been widely studied and developed for the electronic vehicles. In this paper, a full-bridge\\/centertapped push-pull circuit with active clamp-based soft switching bidirectional DC-DC converter and its control method are presented and discussed. From the results of basic experimental demonstration, the proposed system is able to perform adequate

  16. A bi-directional DC-DC converter topology for low power application

    Microsoft Academic Search

    M. Jain; P. K. Jain; M. Daniele

    1997-01-01

    This paper presents a bi-directional DC-DC converter for use in low power applications. The proposed topology is based on a half-bridge on the primary and a current fed push-pull on the secondary side of a high frequency isolation transformer. Achieving bi-directional flow of power using the same power components provides a simple, efficient and galvanically isolated topology that is specially

  17. A bidirectional DC-DC converter topology for low power application

    Microsoft Academic Search

    Manu Jain; M. Daniele; Praveen K. Jain

    2000-01-01

    This paper presents a bidirectional DC-DC converter for use in low power applications. The proposed topology is based on a half-bridge on the primary and a current-fed push-pull on the secondary side of a high frequency isolation transformer. Achieving bidirectional flow of power using the same power components provides a simple, efficient and galvanically isolated topology that is specially attractive

  18. An improved ZVZCS PWM FB DC\\/DC converter using the modified energy recovery snubber

    Microsoft Academic Search

    Eun-Soo Kim; Kee-Yeon Joe; Soon-Gu Park; Yoon-Ho Kim

    2000-01-01

    The conventional high frequency phase-shifted full bridge DC\\/DC converter has a disadvantage that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current, RMS current stress, conduction losses of transformer and switching devices are increased. To alleviate that problem, the paper proposes a circulating current free type high frequency soft switching phase-shifted

  19. A Three-Phase Controlled-Current PWM Converter with Leading Power Factor

    Microsoft Academic Search

    Boon Teck Ooi; John C. Salmon; Juan W. Dixon; Ashok B. Kulkarni

    1987-01-01

    Experimental tests performed on a three-phase bipolartransistor controlled-current PWM power modulator show that it can operate with near-sinusoidal currents at 60 Hz with a 360-degree power angle range. Because of its capability to operate with leading power factor and good waveform, the PWM converter is a promising alternative to the thyristor Graetz bridge. A theoretical method based on the concept

  20. Soft-switched high-frequency, high power DC\\/AC converter with IGBT

    Microsoft Academic Search

    Knut Vangen; Terje Melaa; Alf Khe Adnanes

    1992-01-01

    A 20 kVA direct DC\\/LFAC dual active bridge (DAB) power converter projected for operation at 100 kHz with insulated gate bipolar transistor (IGBT) switches is presented. It has dual-angle, constant-frequency phase shift control, and is soft switched in a large part of the output V-I plane. It also has a high performance digital control system. The topology and its properties

  1. Voltage-Balancing Circuit Based on a Resonant Switched-Capacitor Converter for Multilevel Inverters

    Microsoft Academic Search

    Kenichiro Sano; Hideaki Fujita

    2008-01-01

    This paper proposes a new voltage-balancing circuit for the split dc voltages in a diode-clamped five-level inverter. The proposed circuit is based on a resonant switched-capacitor converter (RSCC), which consists of two half-bridge inverters, a resonant inductor, and a resonant capacitor. A new phase-shift control of the RSCC is proposed to improve voltage-balancing performance. As a result, it is possible

  2. Application of Three-level Converters to Wind Power Systems with Permanent-magnet Synchronous Generators

    Microsoft Academic Search

    Jonq-Chin Hwang; Ming-Hung Chen; Sheng-Nian Yeh

    2007-01-01

    This paper presents the design and implementation of a power control system for variable-speed, permanent-magnet synchronous generators. In this system, a three-phase, full-bridge rectifier and a single-phase, three-level inverter are proposed to convert the three-phase varying voltage and frequency generated by wind to single-phase source with constant voltage and frequency. Specifically, the output power of the overall system is adjusted

  3. Hexagram converter for static VAR compensation

    Microsoft Academic Search

    Jun Wen; K. M. Smedley

    2008-01-01

    A new multilevel converter - Hexagram converter is proposed for static VAR compensation in high-voltage high- power applications. The new converter is composed of six three- phase two-level standard voltage source converter (VSC) modules interconnected through inductors. It has the advantages of modular structure leading to easy construction and maintenance, no voltage unbalance, low voltage stress, low dc energy storage,

  4. Stirling Converters For Solar Power

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1993-01-01

    Two designs expected to meet long-term goals for performance and cost. Proposed for advanced systems to convert solar thermal power to electrical power. Each system, designed to operate with 11-m-diameter paraboloidal reflector, includes solar-energy receiver, liquid-metal heat-transport subsystem, free-piston Stirling engine, cooling subsystem, alternator or generator coupled directly or indirectly to commercial electric-power system, and control and power-conditioning circuitry. System converts approximately 75 kW of input solar thermal power falling on collector to about 25 kW of output electrical power.

  5. Multilevel converters for power system applications

    SciTech Connect

    Lai, J.S.; Stovall, J.P. [Oak Ridge National Lab., TN (United States); Peng, F.Z. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States)

    1995-09-01

    Multilevel converters are emerging as a new breed of power converter options for power system applications. These converters are most suitable for high voltage high power applications because they connect devices in series without the need for component matching. One of the major limitations of the multilevel converters is the voltage unbalance between different levels. To avoid voltage unbalance between different levels, several techniques have been proposed for different applications. Excluding magnetic-coupled converters, this paper introduces three multilevel voltage source converters: (1) diode-clamp, (2) flying-capacitors, and (3) cascaded inverters with separate dc sources. The operation principle, features, constraints, and potential applications of these converters will be discussed.

  6. Soft-switching techniques in PWM converters

    Microsoft Academic Search

    Guichao Hua; Fred C. Lee

    1995-01-01

    A number of soft-switching pulse-width-modulated (PWM) converter techniques have been proposed, aimed at combining the desirable features of both the conventional PWM and resonant converters while avoiding their respective limitations. In this paper, three classes of zero-voltage soft-switching (PWM) converters (namely the zero-voltage-switched (ZVS) quasi-square-wave converters, ZVS-PWM converters, and zero-voltage-transition PWM converters) and two classes of zero-current soft-switching PWM converters

  7. High-power converters for space applications

    NASA Technical Reports Server (NTRS)

    Park, J. N.; Cooper, Randy

    1991-01-01

    Phase 1 was a concept definition effort to extend space-type dc/dc converter technology to the megawatt level with a weight of less than 0.1 kg/kW (220 lb./MW). Two system designs were evaluated in Phase 1. Each design operates from a 5 kV stacked fuel cell source and provides a voltage step-up to 100 kV at 10 A for charging capacitors (100 pps at a duty cycle of 17 min on, 17 min off). Both designs use an MCT-based, full-bridge inverter, gaseous hydrogen cooling, and crowbar fault protection. The GE-CRD system uses an advanced high-voltage transformer/rectifier filter is series with a resonant tank circuit, driven by an inverter operating at 20 to 50 kHz. Output voltage is controlled through frequency and phase shift control. Fast transient response and stability is ensured via optimal control. Super-resonant operation employing MCTs provides the advantages of lossless snubbing, no turn-on switching loss, use of medium-speed diodes, and intrinsic current limiting under load-fault conditions. Estimated weight of the GE-CRD system is 88 kg (1.5 cu ft.). Efficiency of 94.4 percent and total system loss is 55.711 kW operating at 1 MW load power. The Maxwell system is based on a resonance transformer approach using a cascade of five LC resonant sections at 100 kHz. The 5 kV bus is converted to a square wave, stepped-up to a 100 kV sine wave by the LC sections, rectified, and filtered. Output voltage is controlled with a special series regulator circuit. Estimated weight of the Maxwell system is 83.8 kg (4.0 cu ft.). Efficiency is 87.2 percent and total system loss is 146.411 kW operating at 1 MW load power.

  8. Parametric study of laser photovoltaic energy converters

    NASA Technical Reports Server (NTRS)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  9. 23 CFR 650.307 - Bridge inspection organization.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS National Bridge Inspection Standards § 650.307 Bridge inspection organization. (a) Each State...

  10. 23 CFR 650.409 - Evaluation of bridge inventory.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.409 Evaluation of bridge inventory. (a)...

  11. 23 CFR 650.307 - Bridge inspection organization.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS National Bridge Inspection Standards § 650.307 Bridge inspection organization. (a) Each State...

  12. 23 CFR 650.307 - Bridge inspection organization.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS National Bridge Inspection Standards § 650.307 Bridge inspection organization. (a) Each State...

  13. 23 CFR 650.409 - Evaluation of bridge inventory.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.409 Evaluation of bridge inventory. (a)...

  14. 23 CFR 650.409 - Evaluation of bridge inventory.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.409 Evaluation of bridge inventory. (a)...

  15. 23 CFR 650.409 - Evaluation of bridge inventory.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.409 Evaluation of bridge inventory. (a)...

  16. 23 CFR 650.307 - Bridge inspection organization.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS National Bridge Inspection Standards § 650.307 Bridge inspection organization. (a) Each State...

  17. Chickamauga National Military Park Tour Roads, Gordon's Slough Bridge, At ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Chickamauga National Military Park Tour Roads, Gordon's Slough Bridge, At the confluence of Alexander's Bridge Road and Gordon's Slough, southeast of Alexander's Bridge, Fort Oglethorpe, Catoosa County, GA

  18. 23 CFR 650.307 - Bridge inspection organization.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS National Bridge Inspection Standards § 650.307 Bridge inspection organization. (a) Each State...

  19. 23 CFR 650.409 - Evaluation of bridge inventory.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.409 Evaluation of bridge inventory. (a)...

  20. Novel soft-switching DC-DC converter with full ZVS-range and reduced filter requirement. I. Regulated-output applications

    Microsoft Academic Search

    Rajapandian Ayyanar; Ned Mohan

    2001-01-01

    A novel soft-switching topology for DC-DC converters is proposed. It is well suited for applications in the range of a few hundred watts to a few kilowatts. It is essentially a hybrid combination of an uncontrolled half-bridge section and a phase-shift controlled full-bridge section, realized with just four switches. The main features of the proposed topology are zero-voltage-switching down to

  1. A quick convertible agitating system

    Microsoft Academic Search

    Liu Ying; Song Biao; Ni Xiao-yu; Li Jia; Wang Li-jie; Fei Ye-qi; Wang Chang-qin

    2010-01-01

    Experiments of agitator properties are required a lot in process industry. A more efficient, practical and lower cost experimental system is demanded. In this research, a new type of quick convertible agitating system was designed which had a unique structure combined turning bracket with available impeller to enhance the prosperities and efficiency of the agitator experiment. Consisted of one driven

  2. Charge-pump voltage converter

    DOEpatents

    Brainard, John P. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

    2009-11-03

    A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

  3. Power converters for parabolic dishes

    Microsoft Academic Search

    V. C. Truscello; A. N. Williams

    1981-01-01

    The development status of receivers and power conversion units to be used with parabolic dish concentrators is presented. Applications are identified, and the key role played by the power converter element of the collector module is emphasized. The electrical output of the 11-meter-diameter dish modules which are being developed varies up to a maximum of about 25 kilowatts, depending on

  4. CONVERTING ABANDONED LANDS TO CROPLAND

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because of economic conditions, areas of cropland in Ukraine have been left unused for several years. These abandoned lands are now infested with perennial weeds. Producers are interested in converting these lands back to cropland with no-till systems to preserve soil benefits gained by not tillin...

  5. Improved power regenerative controls by using thyristor rectifier bridge of voltage source inverter and a switching transistor

    Microsoft Academic Search

    K. Matsui; U. Mizuno; Y. Murai

    1992-01-01

    A few improved techniques of regenerative control for the voltage source inverter are described. In the proposed equipment, the thyristor rectifier bridge can be also utilized for regeneration through a DC reactor or capacitor. For the first converter mentioned, a novel pulse-width-modulated (PWM) strategy is proposed in which the polarity of the sawtooth carrier waveforms is reversed alternately at every

  6. Bridging faults in BiCMOS circuits

    NASA Technical Reports Server (NTRS)

    Menon, Sankaran M.; Malaiya, Yashwant K.; Jayasumana, Anura P.

    1993-01-01

    Combining the advantages of CMOS and bipolar, BiCMOS is emerging as a major technology for many high performance digital and mixed signal applications. Recent investigations revealed that bridging faults can be a major failure mode in IC's. Effects of bridging faults in BiCMOS circuits are presented. Bridging faults between logical units without feedback and logical units with feedback are considered. Several bridging faults can be detected by monitoring the power supply current (I(sub DDQ) monitoring). Effects of bridging faults and bridging resistance on output logic levels were examined along with their effects on noise immunity.

  7. Bridge Construction and Engineering Learning Center

    NSDL National Science Digital Library

    This website is a great resource for information on bridges. The site provides links to websites like PBS's Nova, where you can learn about different types of bridges and then test your knowledge by matching the right bridge to the right location (over a freeway, river, canyon or ocean waterway), or where you can read more about the forces, loads and materials that affect bridges. Another link takes you to Better Bridges, where you can find out how many bridges are in your state. Definitely a great resource for those armchair engineers but also for teachers and students of physics looking for some great information on this fascinating type of construction.

  8. Homogeneous Bispecifics by Disulfide Bridging

    PubMed Central

    2014-01-01

    We report on a chemical platform to generate site-specific, homogeneous, antibody–antibody conjugates by targeting and bridging disulfide bonds. A bispecific antibody construct was produced in good yield through simple reduction and bridging of antibody fragment disulfide bonds, using a readily synthesized bis-dibromomaleimide cross-linker. Binding activity of antibodies was maintained, and in vitro binding of target antigens was observed. This technology is demonstrated through linking scFv and Fab antibody fragments, showing its potential for the construction of a diverse range of bispecifics. PMID:25033024

  9. Efficiency and Reliability Improvement in Wind Turbine Converters by Grid Converter Adaptive Control

    E-print Network

    Munk-Nielsen, Stig

    Efficiency and Reliability Improvement in Wind Turbine Converters by Grid Converter Adaptive test setup. Keywords >, >, >, >>. Abstract This paper presents a control method that reduces the losses in wind turbine converters adaptively

  10. 23 CFR 650.809 - Movable span bridges.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge shall be selected wherever...

  11. 23 CFR 650.809 - Movable span bridges.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge shall be selected wherever...

  12. 23 CFR 650.809 - Movable span bridges.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge shall be selected wherever...

  13. 23 CFR 650.809 - Movable span bridges.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge shall be selected wherever...

  14. Simplified Method for Estimating Future Scour Depth at Existing Bridges 

    E-print Network

    V Govindasamy, Anand

    2010-07-14

    Bridge scour is the term which describes the erosion of soil surrounding a bridge foundation due to water. Bridge scour can cause the reduction of the load carrying capacity of bridge foundations, excessive foundation ...

  15. 49 CFR 237.71 - Determination of bridge load capacities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...documented in the track owner's bridge management program, together...shall be made by a railroad bridge engineer using appropriate engineering methods and standards that...particularly applicable to railroad bridges. (d) Bridge load...

  16. 49 CFR 237.71 - Determination of bridge load capacities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...documented in the track owner's bridge management program, together...shall be made by a railroad bridge engineer using appropriate engineering methods and standards that...particularly applicable to railroad bridges. (d) Bridge load...

  17. North & South Elevations and Bridge Plan Chickamauga National ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    North & South Elevations and Bridge Plan - Chickamauga National Military Park Tour Roads, Gordon's Slough Bridge, At the confluence of Alexander's Bridge Road and Gordon's Slough, southeast of Alexander's Bridge, Fort Oglethorpe, Catoosa County, GA

  18. 23 CFR 650.809 - Movable span bridges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed bridge shall be selected wherever...

  19. A Framework for Historic Bridge Preservation 

    E-print Network

    Puls, Eric Mark

    2013-08-08

    In an inevitably occurring process, bridges possessing historic, artistic, and engineering significance deteriorate and must be maintained and rehabilitated in order to be kept in service. Ideally, all potentially significant bridges would...

  20. Asymmetric capillary bridges between contacting spheres.

    PubMed

    Farmer, Timothy P; Bird, James C

    2015-09-15

    When a drop of liquid wets two identical solid spheres, the liquid forms a capillary bridge between the spheres to minimize surface energy. In the absence of external forces, these bridges are typically assumed to be axisymmetric, and the shape that minimizes surface energy can be calculated analytically. However under certain conditions, the bridge is axisymmetrically unstable, and migrates to a non-axisymmetric configuration. The goal of this paper is to characterize these non-axisymmetric capillary bridges. Specifically, we numerically calculate the shape of the capillary bridge between two contacting spheres that minimizes the total surface energy for a given volume and contact angle and compare to experiments. When the bridge is asymmetric, finite element calculations demonstrate that the shape of the bridge is spherical. In general, the bridge shape depends on both volume and contact angle, yet we find the degree of asymmetry is controlled by a single parameter. PMID:26037268

  1. Wind effect on long span bridge

    E-print Network

    Zhang, Xi, M. Eng. Massachusetts Institute of Technology

    2012-01-01

    This thesis has studied different types of reactions of long span bridge under wind load, such as vortex shedding, flutter and buffeting. Since all of these conditions have the chance to damage bridge structure, we calculate ...

  2. A Multicell Converter Model of DBD Plasma Discharges

    SciTech Connect

    Flores-Fuentes, A. A.; Piedad-Beneitez, A. de la [Instituto Tecnologico de Toluca, AP 890, Toluca (Mexico); Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia A, R.; Barocio, S. R. [Instituto Nacional de Investigaciones Nucleares, AP 18-1027, 11801, Mexico D.F. (Mexico); Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O. [Instituto Tecnologico de Toluca, AP 890, Toluca (Mexico); Instituto Nacional de Investigaciones Nucleares, AP 18-1027, 11801, Mexico D.F. (Mexico)

    2006-12-04

    A compact Matlab model of plasma discharges in a DBD reactor consisting of two parallel electrode plates with a small gap and a thin dielectric sheet between them is reported. Its DBD plasma is modelled as a voltage controlled current-source switched on when the voltage across the gap exceeds the breakdown voltage. A three cell voltage-source inverter, configured in half-bridge, has been used as a power supply. This configuration has an excellent performance when operating as an open-loop. The distribution of total energy between a large number of low power converters proofs to be advantageous, allowing an efficient high power drive. Simulation results show that the current source and its output current tend to follow an exponential behaviour. A phenomenological characteristic of the voltage-current behaviour of DBD is then described by power laws with different voltage exponent function values.

  3. Low Head, Vortex Induced Vibrations River Energy Converter

    SciTech Connect

    Bernitsas, Michael B.; Dritz, Tad

    2006-06-30

    Vortex Induced Vibrations Aquatic Clean Energy (VIVACE) is a novel, demonstrated approach to extracting energy from water currents. This invention is based on a phenomenon called Vortex Induced Vibrations (VIV), which was first observed by Leonardo da Vinci in 1504AD. He called it ‘Aeolian Tones.’ For decades, engineers have attempted to prevent this type of vibration from damaging structures, such as offshore platforms, nuclear fuel rods, cables, buildings, and bridges. The underlying concept of the VIVACE Converter is the following: Strengthen rather than spoil vortex shedding; enhance rather than suppress VIV; harness rather than mitigate VIV energy. By maximizing and utilizing this unique phenomenon, VIVACE takes this “problem” and successfully transforms it into a valuable resource for mankind.

  4. A study of the high frequency limitations of series resonant converters

    NASA Technical Reports Server (NTRS)

    Stuart, T. A.; King, R. J.

    1982-01-01

    A transformer induced oscillation in series resonant (SR) converters is studied. It may occur in the discontinuous current mode. The source of the oscillation is an unexpected resonant circuit formed by normal resonance components in series with the magnetizing inductance of the output transformers. The methods for achieving cyclic stability are: to use a half bridge SR converter where q0.5. Q should be as close to 1.0 as possible. If 0.5q1.0, the instability will be avoided if psi2/3q-1/3. The second objective was to investigate a power field effect transistor (FET) version of the SR converter capable of operating at frequencies above 100 KHz, to study component stress and losses at various frequencies.

  5. A study of DC-DC converters with MCT's for arcjet power supplies

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.

    1994-01-01

    Many arcjet DC power supplies use PWM full bridge converters with large arrays of parallel FET's. This report investigates an alternative supply using a variable frequency series resonant converter with small arrays of parallel MCT's (metal oxide semiconductor controlled thyristors). The reasons for this approach are to: increase reliability by reducing the number of switching devices; and decrease the surface mounting area of the switching arrays. The variable frequency series resonant approach is used because the relatively slow switching speed of the MCT precludes the use of PWM. The 10 kW converter operated satisfactorily with an efficiency of over 91 percent. Test results indicate this efficiency could be increased further by additional optimization of the series resonant inductor.

  6. Portable convertible blast effects shield

    DOEpatents

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler,; Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

    2010-10-26

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

  7. Portable convertible blast effects shield

    DOEpatents

    Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

    2007-05-22

    A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

  8. SEISMIC RETROFIT OF VINCENT THOMAS SUSPENSION BRIDGE

    Microsoft Academic Search

    George Baker; Tim Ingham; Dan Heathcote

    1998-01-01

    The Vincent Thomas Bridge in Los Angeles, California, is a major suspension bridge with a total length of 1848 m (6,060 ft), including approaches, and a main span bridge 766 m (2,513 ft) long, whose center span in 458 m (1,500 ft). The bridge, built in the 1960s, used the seismic codes of the time. The site conditions and tall,

  9. Bridge building and bridge conservation in agreement with the genius loci

    Microsoft Academic Search

    Dirk Bühler

    Bridges ideally stand for the convergence of engineering landmarks and aesthetical attractions. But what's even more: bridges can be signs that reveal their meaning only by means of a skilful integration to their surrounding landscape or urban context. The appreciation of the spirit of place where bridge building happens is a substantial part for successful bridge design. The paper includes

  10. Bridge 11/13/2007 1 Example 1. Find the probability that a bridge hand contains

    E-print Network

    Taylor, Peter

    Bridge 11/13/2007 1 Bridge Example 1. Find the probability that a bridge hand contains no aces of getting a no-ace hand is the propor- tion of all possible hands that have no aces. Now in Pascal we have calculated the total number of bridge hands as 52 13 . Now we ask how many of these contain no aces

  11. Auto protected ZVS-ZCS half bridge with parallel power regulation

    Microsoft Academic Search

    Philippe Perol; Giulio Simonelli; K. Ou

    2001-01-01

    ESTEC has developed and patented in 1988 a ZVS-ZCS topology which is essentially a current fed resonant push-pull or half-bridge. This topology provides only voltage adaptation. When voltage regulation is needed, a buck converter is usually put up-front. The disadvantage of this combined concept is to handle the full power through two stages and to request an input filter, while

  12. Design, Simulation and implementation of an adaptive controller on base of artificial neural networks for a resonant DC-DC converter

    Microsoft Academic Search

    Mohammad Jafari; Zahra Malekjamshidi

    2011-01-01

    A new method of control for high-voltage Full Bridge Series-Parallel Resonant (FBSPR) DC-DC converter with capacitive output filter, using Artificial Neural Networks (ANN) is proposed in this paper. The output voltage regulation obtained via high switching frequency and Soft switching operation (ZCS and ZVS technologies) to decrease the losses and optimize the efficiency of converter. In the following sections, The

  13. Novel High Frequency Planner Transformer Linked Soft Switching DC-DC Power Converter with Secondary Side-Phase Shifted PWM Active Rectifying Switches

    Microsoft Academic Search

    N. A. Ahmed; M. Miyatake; K. Nishimura; Hyun-Woo Lee; M. Nakaoka

    2005-01-01

    This paper presents a novel circuit topology of isolated DC-DC power converter, which includes stable and efficient zero voltage soft switching (ZVS) full bridge inverter in the high frequency planner transformer primary-side and zero current soft switching rectifier in its secondary side. This power converter incorporates zero current soft switching (ZCS) phase-shifted PWM controlled two active power switches in series

  14. High efficiency thermionic converter studies

    NASA Technical Reports Server (NTRS)

    Huffman, F. N.; Sommer, A. H.; Balestra, C. L.; Briere, D. P.; Oettinger, P. E.

    1976-01-01

    The objective is to improve thermionic converter performance by means of reduced interelectrode losses, greater emitter capabilities, and lower collector work functions until the converter performance level is suitable for out-of-core space reactors and radioisotope generators. Electrode screening experiments have identified several promising collector materials. Back emission work function measurements of a ZnO collector in a thermionic diode have given values less than 1.3 eV. Diode tests were conducted over the range of temperatures of interest for space power applications. Enhanced mode converter experiments have included triodes operated in both the surface ionization and plasmatron modes. Pulsed triodes were studied as a function of pulse length, pulse potential, inert gas fill pressure, cesium pressure, spacing, emitter temperature and collector temperature. Current amplifications (i.e., mean output current/mean grid current) of several hundred were observed up to output current densities of one amp/sq cm. These data correspond to an equivalent arc drop less than 0.1 eV.

  15. Full-bridge capacitive extensometer

    Microsoft Academic Search

    Randall D. Peters

    1993-01-01

    Capacitive transducers have proven to be very effective sensors of small displacements, because of inherent stability and noninvasive high resolution. The most versatile ones have been those of a differential type, in which two elements are altered in opposite directions in response to change of the system parameter being monitored. Oftentimes, this differential pair has been incorporated into a bridge

  16. Over the Ramp: Building Bridges

    ERIC Educational Resources Information Center

    Sutton, Mary

    2007-01-01

    TheatreWorks is the third largest theatre in the San Francisco bay area. Through the usual educational programs that $6 million companies tend to offer, it has reached over 100,000 students of all ages in the past 8 years. The TheatreWorks Bridges Projects, however, are special. They are intricate and expansive, work with multiple community…

  17. Bridges on the River Quad

    NSDL National Science Digital Library

    2011-03-27

    In this activity, students graph a quadratic function that models the shape of a bridge trestle and then solve the related quadratic equation by completing the square. Students use the calculators’ capabilities to find the x-intercepts and the maximum value on the graph. Teacher notes, detailed instructions on using graphing calculators, and questions to check comprehension aid in teaching the lesson.

  18. ADVANCED COMPOSITE MATERIALS HEAT BRIDGES

    Microsoft Academic Search

    A. B. Shopen; V. A. Golovanevskiy; O. A. Kivirenko

    Understanding heat transfer properties of advanced composite materials (CM) structures is gaining increasing importance in industries such as medicine and cryogenics, aerospace and electronics where structures made from advanced CM are being used as heat bridges. The main goal in such applications of advanced CM structures is achieving maximum load bearing capacity while maintaining heat transfer rate at a predetermined

  19. Percentage Problems in Bridging Courses

    ERIC Educational Resources Information Center

    Kachapova, Farida; Kachapov, Ilias

    2012-01-01

    Research on teaching high school mathematics shows that the topic of percentages often causes learning difficulties. This article describes a method of teaching percentages that the authors used in university bridging courses. In this method, the information from a word problem about percentages is presented in a two-way table. Such a table gives…

  20. Cell modulated DC/DC converter

    E-print Network

    Warren, James Raymond, III

    2005-01-01

    A very high frequency converter roughly based on a class E topology is investigated for replacing a conventional boost converter circuit. The loss mechanisms in class E inverters are characterized, and metrics are developed ...

  1. Novel zero-voltage-transition PWM converters

    Microsoft Academic Search

    Guichao Hua; Ching-Shan Leu; Fred C. Lee

    1992-01-01

    A class of zero voltage transition (ZVT) power converters is proposed in which both the transistor and the rectifier operate with zero voltage switching and are subjected to minimum voltage and current stresses. The boost ZVT-PWM converter is used as an example to illustrate the operation of these converters. A 300 kHz, 600 W ZVT-PWM boost, DC-DC converter, and a

  2. Integrated converters for switched reluctance motor drives

    Microsoft Academic Search

    Z. Nie; A. Emadi

    2004-01-01

    Switched reluctance motors (SRM) are relatively inexpensive and robust. The proportional cost of the power electronics is large especially for lower power drives. It is therefore important to optimize the power converter for the practical applications. This work presents the concept of integrated converters for SRM drives. Basic converters based on the sub-integrated concept are also discussed for the purpose

  3. Light-off behavior of catalytic converters

    Microsoft Academic Search

    P. S. Hagan; D. W. Schwendeman

    1994-01-01

    This paper studies a system of partial differential equations modeling the behavior of an automotive catalytic converter. The particular phenomenon considered in detail is light-off, when the temperature of the converter changes dramatically from cold to hot somewhere within the converter. The initial position of light-off and the subsequent movement of this steep jump in temperature toward the inlet of

  4. COMMUNITY ALERT INCIDENT: Catalytic Converter Thefts

    E-print Network

    Rose, Michael R.

    COMMUNITY ALERT C R I M E INCIDENT: Catalytic Converter Thefts DETAILS: There has been a recent series of catalytic converter thefts from vehicles in parking lots adjacent to campus housing communities. The suspect(s) typically go underneath the victim's vehicle to steal the catalytic converter. A catalytic

  5. Digital scan converters in diagnostic ultrasound imaging

    Microsoft Academic Search

    JONATHAN OPHIR; N. F. Maklad

    1979-01-01

    The use of digital scan converters in ultrasonic imaging is presented. The basic principles of ultrasound physics and imaging are briefly reviewed. A detailed description of the components and principles of operation of digital scan converters follows. The capabilities of current digital scan converters in terms of resolution, writing speed, pre-processing and postprocessing, and new rapid scanning techniques are discussed.

  6. Diode-quad bridge circuit means

    NASA Technical Reports Server (NTRS)

    Harrison, D. R.; Dimeff, J. (inventors)

    1975-01-01

    Diode-quad bridge circuit means is described for use as a transducer circuit or as a discriminator circuit. It includes: (1) a diode bridge having first, second, third, and fourth bridge terminals consecutively coupled together by four diodes polarized in circulating relationship; (2) a first impedance connected between the second bridge terminal and a circuit ground; (3) a second impedance connected between the fourth bridge terminal and the circuit ground; (4) a signal source having a first source terminal capacitively coupled to the first and third bridge terminals, and a second source terminal connected to the circuit ground; and (5) an output terminal coupled to the first bridge terminal and at which an output signal may be taken.

  7. Modeling and space vector control of a novel multilevel matrix converter for variable-speed wind power generators

    NASA Astrophysics Data System (ADS)

    Al-Naseem, Osama Abdulrahman

    A novel multilevel matrix converter is developed to efficiently transfer energy between a three-phase variable-speed generator of a wind turbine and a three-phase ac utility network. Optimizing the energy transfer efficiency at light load is critical in variable-speed wind generators. Laboratory experiment suggests that converter efficiency at light load may be increased via soft-switching and multilevel switching techniques. The new converter includes the advantages of multilevel converters, such as reduced harmonic content, increased power handling capability without additional switching loss, and high efficiency at low machine voltages. It also features the characteristics of conventional matrix converters, such as space vector control and improved efficiency via auxiliary resonant commutation soft-switching techniques. Similar to a conventional matrix converter, the novel multilevel matrix converter uses a nine-switch matrix with four-quadrant switches to connect input phases at one side of the converter with output phases at the other side of the converter. However, the switches of the new converter are configured differently from those used in the conventional matrix converter. Each switch of the new converter is a cell that resembles a full-bridge inverter topology and can assume three voltage levels while used. Semiconductor devices in a switch cell are always clamped to a known constant do voltage of a capacitor. This is a typical characteristic of multilevel converters where device voltage stresses are reduced by clamping the main transistor voltages to low levels. With reduced voltage stresses, switching frequency can be increased to allow for reduced size of filter magnetics. Unlike conventional matrix converter, the multilevel matrix converter uses inductors on both input and output sides of the converter. This symmetry allows for both step up and step down operations. Each switch cell features double the power handling capability compared to the four-quadrant switches used in a conventional matrix converter. This increase in power handling capability is due to the doubling of the number of devices in a multilevel matrix converter switch cell. Scaling up the power handling capability is accomplished by cascading more than one switch cell per branch. Control of the new converter is achieved through space vector modulation in which three-phase ac voltages are transformed to the d-q reference frame and compared with a set of space vectors prior to modulation. Since it has 19683 different switching combinations, control can be difficult and complex. Nevertheless, the multilevel matrix converter has been modeled and controlled through simulation. Simulation results show the possibility of operating the converter to produce the desired voltage waveforms with universal input and output power factors and maintain constant capacitor voltages simultaneously. Also in this dissertation is the derivation of an analytical averaged equivalent circuit model of a PWM converter. This model reveals how dominant loss mechanisms vary with converter operating point. The model is based on the operational characteristics of power diodes and IGBTs. Laboratory experiments support the derived model and confirm that IGBT current tailing and diode reverse-recovery are indeed the most critical losses in a PWM converter. These losses are more significant at light load, hence reducing the energy capture capability of converters used in wind generation. The results suggest that multilevel conversion, which has been employed in the novel multilevel matrix converter, could improve the low-wind converter efficiency.

  8. Auxiliary resonant DC tank converter

    DOEpatents

    Peng, Fang Z. (Knoxville, TN)

    2000-01-01

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

  9. Lightweight multiple output converter development

    NASA Technical Reports Server (NTRS)

    Kisch, J. J.; Martinelli, R. M.

    1978-01-01

    A high frequency, multiple output power conditioner was developed and breadboarded using an eight-stage capacitor diode voltage multiplier to provide +1200 Vdc, and a three-stage for -350 Vdc. In addition, two rectifier bridges were capacitively coupled to the eight-stage multiplier to obtain 0.5 and 0.65 a dc constant current outputs referenced to +1200 Vdc. Total power was 120 watts, with an overall efficiency of 85 percent at the 80 kHz operating frequency. All outputs were regulated to three percent or better, with complete short circuit protection. The power conditioner component weight and efficiency were compared to the equivalent four outputs of the 10 kHz conditioner for the 8 cm ion engine. Weight reduction for the four outputs was 557 grams; extrapolated in the same ratio to all nine outputs, it would be 1100 to 1400 grams.

  10. Converting Petroleum Coke to Electricity

    E-print Network

    Pavone, A.

    as compared to soft coal, has also created flame stability problems for both initial ignition, and sustained ignition. Lastly, ash deposition in the form of slagging on heat transfer surface walls has sometimes been a problem in utility scale boilers... (250 psig) slagging gasifier that introduces both oxygen and steam. The reaction is designed to convert coke to a synthesis gas mixture of CO and H2. Sulfur in the form of H2S is removed ESL-IE-92-04-47 Proceedings from the 14th National Industrial...

  11. A Hybrid Energy System Using Cascaded H-bridge Converter , Zhong Du2

    E-print Network

    Tolbert, Leon M.

    power on the ac side is through a multi-phase transformer, shown in Fig. 1. The usage of multi in transients; and (5) They are prone to failure [6]. Transformer Transformer Static Isolator Utility 3-phases Fig. 1. Hybrid energy system where power is combined on the ac side through a transformer

  12. High power density dc-to-dc converters for aerospace applications

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    Three dc-to-dc converter topologies aimed at high-power high-frequency applications are introduced. Major system parasitics, namely, the leakage inductance of the transformer and the device output capacitance are efficiently utilized. Of the three circuits, the single-phase and three-phase versions of the dual active bridge topology demonstrate minimal stresses, better utilization of the transformer, bidirectional, and buck-boost modes of operation. All circuits operate at a constant switching frequency, thus simplifying design of the reactive elements. The power transfer characteristics and soft-switching regions on the Vout-Iout plane are identified. Two coaxial transformers with different cross-sections were built for a rating of 50 kVA. Based on the single-phase dual active bridge topology, a 50 kW, 50 kHz converter operating at an input voltage of 200 Vdc and an output voltage of 1600 Vdc was fabricated. Characteristics of current-fed output make the dual active bridge topologies amenable to paralleling and hence extension to megawatt power levels. Projections to a 1 MW system operating from a 500 Vdc input, at an output voltage of 10 kVdc and a switching frequency of 50 kHz, using MOS-controlled thyristors, coaxially wound transformers operating at three times the present current density with cooling, and multilayer ceramic capacitors, suggests an overall power density of 0.075 to 0.08 kg/kW and an overall efficiency of 96 percent.

  13. New oxa-bridged macrocycles.

    PubMed

    Panten, Johannes; Surburg, Horst; Hölscher, Bernd

    2008-06-01

    In creating new aroma molecules, the fragrance chemist can make use of several tools: receptor or combinatorial research as well as lead structure optimization of existing chemicals or substances from the natural pool. Sometimes, it is also possible to discover new structures via another way: the careful analysis of existing products and their production processes. In analyzing the production process of 1-oxacyclohexadecan-2-one (6), we identified at least two new oxa-bridged macrocyclic molecules. In continuation, these results inspired us to synthesize and evaluate more representatives with similar structures. In this contribution, presented at the RSC/SCI conference 'flavours & fragrances 2007' in London, September 24-26, 2007, the synthesis and olfactory properties of several new oxa-bridged macrocycles will be introduced and discussed. PMID:18618411

  14. Scour assessment at bridges from Flag Point to Million Dollar Bridge, Copper River Highway, Alaska

    USGS Publications Warehouse

    Brabets, T.P.

    1994-01-01

    Twelve bridges are located along the Copper River Highway from Flag Point (Mile 27) to lhe Million Dollar Bridge (Mile 48). These bridges cross all or parts of the Copper River. Channel scour at these bridges was assessed by collecting and analyzing discharge and sediment data, analyzing aerial photography for eight different years, surveying and comparing cross sections, and utilizing scour equations. Between 1968 and 1992, scour occurring at Bridge 331 has formed two distinct channels at the bridge. The channel at Bridge 1187 has remained relatively unchanged between 1968 and 1992. During this same time period, the channel at Bridge 332 appears to have gradually filled. However, during the 1992 runoff season, the channel at this bridge scoured significantly, probably because of its unstable nature. The most significant scour has occurred at Bridge 342. A high-water period in 1981 probably shifted much of the flow of the Copper River through this bridge. As a result, severe contraction scour occurred which required major repairs to the bridge. During 1991 and 1992, the approach channel to Bridge 342 has been migrating, causing scour in the left side of the channel. Bed material at the Million Dollar Bridge consists of hard unweathered boulders nested in dense gravel. Because of this type of erosion-resistant material, no significant scour has occurred at this site. Contraction scour equations overestimated the mean depth of flow at Bridge 331 by 2.6 to 5.0 ft, but were within 1.0 ft of the mean depth of flow for Bridge 1187. The local scour equations generally overestimated local scour at both Bridge 331 and Bridge 1187. The accuracy of some equations was probably affected because water velocities could not be obtained upstream from the piers.

  15. A dc to dc converter

    NASA Technical Reports Server (NTRS)

    Willis, A. E.; Gould, J. M.; Matheney, J. L.; Garrett, H. (inventors)

    1984-01-01

    The object of the invention is to provide an improved converter for converting one direct current voltage to another. A plurality of phased square wave voltages are provided from a ring counter through amplifiers to a like plurality of output transformers. Each of these transformers has two windings, and S(1) winding and an S(2) winding. The S(1) windings are connected in series, then the S(2) windings are connected in series, and finally, the two sets of windings are connected in series. One of six SCRs is connected between each two series connected windings to a positive output terminal and one of diodes is connected between each set of two windings of a zero output terminal. By virtue of this configuration, a quite high average direct current voltage is obtained, which varies between full voltage and two-thirds full voltage rather than from full voltage to zero. Further, its variation, ripple frequency, is reduced to one-sixth of that present in a single phase system. Application to raising battery voltage for an ion propulsion system is mentioned.

  16. Microstrip superheterodyne coherent microwave bridge

    Microsoft Academic Search

    A. I. Rokeakh; A. M. Batin; O. B. Makhnev; A. A. Mekhonoshin; Yu. A. Sherstkov; A. A. Lisitsin; V. Yu. Yazan

    1995-01-01

    Reasons for unsatisfactory operation of the superheterodyne spectrometers at increased microwave power are considered. Recommendations\\u000a for designing the superheterodyne microwave bridge of the EPR spectrometer working at the microwave power of about hundreds\\u000a of milliwatt are given. These recommendations allow one to develop the spectrometer comparable to those with modulation of\\u000a resonant conditions concerning reliability, stability and simplicity of operation.

  17. Modal Identification of Tsing MA Bridge by Using Improved Eigensystem Realization Algorithm

    NASA Astrophysics Data System (ADS)

    QIN, Q.; LI, H. B.; QIAN, L. Z.; LAU, C.-K.

    2001-10-01

    This paper presents the results of research work on modal identification of Tsing Ma bridge ambient testing data by using an improved eigensystem realization algorithm. The testing was carried out before the bridge was open to traffic and after the completion of surfacing. Without traffic load, ambient excitations were much less intensive, and the bridge responses to such ambient excitation were also less intensive. Consequently, the bridge responses were significantly influenced by the random movement of heavy construction vehicles on the deck. To cut off noises in the testing data and make the ambient signals more stationary, the Chebyshev digital filter was used instead of the digital filter with a Hanning window. Random decrement (RD) functions were built to convert the ambient responses to free vibrations. An improved eigensystem realization algorithm was employed to improve the accuracy and the efficiency of modal identification. It uses cross-correlation functions ofRD functions to form the Hankel matrix instead of RD functions themselves and uses eigenvalue decomposition instead of singular value decomposition. The data for response accelerations were acquired group by group because of limited number of high-quality accelerometers and channels of data loggers available. The modes were identified group by group and then assembled by using response accelerations acquired at reference points to form modes of the complete bridge. Seventy-nine modes of the Tsing Ma bridge were identified, including five complex modes formed in accordance with unevenly distributed damping in the bridge. The identified modes in time domain were then compared with those identified in frequency domain and finite element analytical results.

  18. Thermionic converter emitter support arrangement

    DOEpatents

    Allen, Daniel T. (La Jolla, CA)

    1990-01-01

    A support is provided for use in a therminonic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  19. Thermionic converter emitter support arrangement

    DOEpatents

    Allen, Daniel T. (La Jolla, CA)

    1990-01-01

    A support is provided for use in a thermionic converter to support an end an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housng, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  20. Horizontal bridges in polar dielectric liquids

    NASA Astrophysics Data System (ADS)

    Woisetschläger, Jakob; Wexler, Adam D.; Holler, Gert; Eisenhut, Mathias; Gatterer, Karl; Fuchs, Elmar C.

    2012-01-01

    When a high-voltage direct-current is applied to two beakers filled with polar liquid dielectrica like water or methanol, a horizontal bridge forms between the two beakers. By repeating a version of Pellat's experiment, it is shown that a horizontal bridge is stable by the action of electrohydrodynamic pressure. Thus, the static and dynamic properties of the phenomenon called a `floating water bridge' can be explained by the gradient of Maxwell pressure, replenishing the liquid within the bridge against any drainage mechanism. It is also shown that a number of liquids can form stable and long horizontal bridges. The stability of such a connection, and the asymmetry in mass flow through such bridges caused by the formation of ion clouds in the vicinity of the electrodes, is also discussed by two further experiments.

  1. An Isolated Bidirectional DC-DC Converter based Super-Capacitor Interface for Automobile Electric Power Systems

    Microsoft Academic Search

    Eiji Hiraki; Koji Yamamoto; Toshihiko Tanaka; Tomokazu Mishima; Mutsuo Nakaoka

    2006-01-01

    In recent years, power electronic energy storage systems using super capacitor bank have been widely studied and developed for the electronic vehicles. In this paper, a full-bridge\\/centertapped push-pull circuit-based bidirectional DC-DC converter and its control method are proposed and discussed. From the results of detailed experimental demonstration, the proposed system is able to perform adequate charging and discharging operation between

  2. Nonlinear optical polymer applicable for all-optical wavelength converters in communications bands near 1.5 ?m

    Microsoft Academic Search

    Seung Koo Park; Jung Yun Do; Jung Jin Ju; Min-su Kim; Myung-Hyun Lee

    2005-01-01

    We prepared acrylic nonlinear optical (NLO) polymers that contained a chromophore with a ?-conjugated imine bridge between phenyl and benzothiazole groups, 2-(methyl-{4-[(6-nitro-benzenothiazol-2-ylimino)-methyl]-phenyl}-amino)-ethanol, for all-optical wavelength converters in optical fiber communication. The glass transition temperature (Tg) of the copolymers is between 130 and 143 °C. The molecular weights of the copolymers are comparatively high for obtaining films. An NLO polymer film

  3. Performance of Power Converters at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2001-01-01

    Power converters capable of operation at cryogenic temperatures are anticipated to play an important role in the power system architecture of future NASA deep space missions. Design of such converters to survive cryogenic temperatures will improve the power system performance and reduce development and launch costs. Aerospace power systems are mainly a DC distribution network. Therefore, DC/DC and DC/AC converters provide the outputs needed to different loads at various power levels. Recently, research efforts have been performed at the NASA Glenn Research Center (GRC) to design and evaluate DC/DC converters that are capable of operating at cryogenic temperatures. This paper presents a summary of the research performed to evaluate the low temperature performance of five DC/DC converters. Various parameters were investigated as a function of temperature in the range of 20 to -196 C. Data pertaining to the output voltage regulation and efficiency of the converters is presented and discussed.

  4. Converted-wave seismology for coal exploration

    Microsoft Academic Search

    Natasha Hendrick

    Despite the success of multi-component seismology and asso- ciated converted-wave (PS-wave) imaging methods in the petroleum industry, there has been relatively little effort devoted to shallow, high-resolution converted-wave imaging in the coal sector. By analogy to petroleum-scale applications, converted-wave seismic imaging in the coal environment offers interesting possibilities for independent validation of mapped stru c t u res, clearer imaging

  5. Novel zero-current-transition PWM converters

    Microsoft Academic Search

    Guichao Hua; Eric X. Yang; Yimin Jiang; Fred C. Lee

    1993-01-01

    A new family of zero-current-transition (ZCT) pulse-width-modulated (PWM) converters are proposed. The new family of converters implements zero-current turn-off for power transistor(s) without increasing voltage\\/current stresses and operates at a fixed frequency. The proposed converters are deemed most suitable for high-power applications where the minority-carrier semiconductor devices (such as IGBTs, BJTs, and MCTs) are predominantly used as the power switches.

  6. Novel zero-current-transition PWM converters

    Microsoft Academic Search

    Guichao Hua; Eric X. Yang; Yimin Jiang; Fred C. Lee

    1994-01-01

    A new family of zero-current-transition (ZCT) pulsewidth-modulated (PWM) converters is proposed. The new family of converters implements zero-current turn-off for power transistor(s) without increasing voltage\\/current stresses and operates at a fixed frequency. The proposed converters are deemed most suitable for high-power applications where the minority-carrier semiconductor devices (such as IGBTs, BJTs, and MCTs) are predominantly used as the power switches.

  7. Inverting ZCS Switched-Capacitor Bidirectional Converter

    Microsoft Academic Search

    Yaung-Shung Lee; Yin-Yuan Chiu; Ming-Wang Cheng

    2006-01-01

    The proposed inverting type zero-current switching switched-capacitor (ZCS SC) DC\\/DC converters are a new type of bi-directional power flow control conversion schemes. They possess high efficiency, low EMI emission and current stress features for the proposed quasi-resonant switched-capacitor inverting converters. A family of inverting type zero-current switching switched-capacitor bi-directional converters is presented, which can improve the current stress problem during

  8. A Novel Lossless Snubber for Boost Converters

    Microsoft Academic Search

    J. Marshall; M. Kazerani

    2006-01-01

    Advanced transportation technologies, such as hybrid-electric vehicles, battery-electric vehicles, and fuel cell vehicles, rely on high-power DC\\/DC converters to interconnect and manage their power systems. Boost converters are especially useful in stepping-up the voltage from a battery or fuel cell to match the electric motor voltage range. However, conventional high-power boost converters are very large and heavy, partly due to

  9. Development of Hybrid Bridges: State of Arts and Conceptual Design

    Microsoft Academic Search

    Suhaib Yahya Kasim Al-Darzi; Airong Chen

    2006-01-01

    A state of the art of developments of the Hybrid bridges is presented focusing on steel-concrete composite bridges, considering the steel beam, concrete deck and connections developments. The analysis and design methods of composite bridge structures, connections, the reliability and life cycle of bridges, new bridge system forms and the use of alternative materials are reviewed with some possible applications.

  10. Monitoring Bridge Deformations during Static Loading Tests Using GPS

    Microsoft Academic Search

    Moustafa A. BARAKA; Adel H. EL-SHAZLY

    SUMMARY The static loading test of a bridge is a fundamental check of the actual behavior of a bridge under extreme loading conditions. By measuring bridge deformations and comparing it to expected theoretical values resulting from design, bridge safety can be assessed. In this paper, GPS is presented as a viable tool to monitor bridge deformation in Egypt. GPS was

  11. 3. CONTEXTUAL VIEW OF BRIDGE IN SETTING, LOOKING SOUTHWEST FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. CONTEXTUAL VIEW OF BRIDGE IN SETTING, LOOKING SOUTHWEST FROM ELEVATED GRADE OF EUREKA SOUTHERN RAILROAD. EUREKA SOUTHERN TRUSS BRIDGE AT EXTREME LEFT, 1924 HIGHWAY BRIDGE IN CENTER, 1952 HIGHWAY BRIDGE AT RIGHT - Van Duzen River Bridge, Spanning Van Duzen River at CA State Highway 101, Alton, Humboldt County, CA

  12. 11. Photocopy of photograph, c. 1900. VIEW OF BRIDGE STREET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Photocopy of photograph, c. 1900. VIEW OF BRIDGE STREET BRIDGE NEAR FLOOD STAGE, LOOKING NORTHEAST. (Original in Union City Historical Museum.) 8'x10' enlargement from 4'x5' negative. - Bridge Street Bridge, Spanning Little French Creek at Bridge Street, Union City, Erie County, PA

  13. Bridge deck designs for railing impacts 

    E-print Network

    Arnold, Althea Gayle

    1984-01-01

    ) Standard Specifications for Highway Bridges set forth certain structural design requirements for bridge railings and the corresponding bridge decks. Observat1ons of deck failure patterns in recent crash tests and observed deck fa1lures at vehicle... in Texas. Full-scale deck sections with a post, a parapet or an 8 ft section of railing were built and tested. The three types tested were the Texas TIOI, T202, and TS bridge railings. The findings of this testing are reported herein. ACKNOHLEDGEMENT...

  14. Relationship between myocardial bridging and coronary arteriosclerosis.

    PubMed

    Sun, Jian Ling; Huang, Wei Min; Guo, Ji Hong; Li, Xiao Ying; Ma, Xian Lin; Wang, Chong Yu

    2013-04-01

    The objective of the study was to explore the prevalence and characteristics of myocardial bridging in patients who underwent coronary angiography and to also evaluate the correlation between bridged coronary segments and atherosclerosis. For this purpose, clinical materials of 1,500 patients who had received coronary angiography were retrospectively analyzed. The location and length of the myocardial bridge were recorded as well as the extent and location of coronary artery stenosis was described. Segments proximal and distal to the bridging were evaluated for coronary arteriosclerosis as were the remaining coronary segments. We found that myocardial bridging was present in 179 (11.9 %) patients. Bridges were frequently (84.9 %) localized in the mid-distal segment of the left anterior descending (LAD) artery. Myocardial bridging was not considered a significant risk factor for coronary atherosclerosis (odds ratio 0.58) compared with traditional cardiovascular risk factors. The incidence of coronary arteriosclerosis in the distal segments was significantly less affected than the proximal segments (P < 0.01). It was, therefore, concluded that myocardial bridging frequently localized in the mid-distal segment of the LAD artery. The presence of myocardial bridging promotes proximal atherosclerosis but it is not an additional risk factor for coronary atherosclerosis. PMID:23076634

  15. Pulse doubling in zigzag-connected autotransformer-based 12-pulse ac-dc converter for power quality improvement

    NASA Astrophysics Data System (ADS)

    Abdollahi, Rohollah

    2012-12-01

    This paper presents a pulse doubling technique in a 12-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMDs) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 12-pulse rectified output voltage is accomplished via two paralleled six-pulse acdc converters each of them consisting of three-phase diode bridge rectifiers. An autotransformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 24 pulses. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse, 12-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.

  16. A theoretical study of photovoltaic converters

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.

    1987-01-01

    Mathematical models for the photovoltaic conversion of laser power were developed. These models simulate the operation of planar and vertical junction photovoltaic converters and are described in detail.

  17. A variable parameter thermionic energy converter 

    E-print Network

    Bragg, Bobby Joe

    1967-01-01

    . In describing the electron energy gain and loss pro- cesses in the interelectrode region, he notes that, at a particular point in the interelectrode plasma, the rates of energy gain and loss for the electron gas balance, and the electron kinetic energy flux... LIST OF FIGURES FIGURE 1. SIMPLE SCHEMATIC OF A THERMIONIC CONVERTER PAGE 2. POWER VS SPACING WITH A MINIMUM POWER POINT 3. POWER VS SPACING WITH NO MINIMUM POWER POINT 4. CONVERTER MOTIVE DIAGRAM~ O'E = 5. CONVERTER MOTIVE DIAGRAM~ 6. CONVERTER...

  18. DC/DC Converter Stability Testing Study

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2008-01-01

    This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

  19. Distributed interleaving of paralleled power converters

    E-print Network

    Kassakian, J.G.

    This paper introduces a distributed approach to interleaving paralleled power converter cells. Unlike conventional methods, the distributed approach requires no centralized control, automatically accommodates varying numbers ...

  20. 6. VIEW OF GDOT BRIDGE NO. 02700268X00678N BRIDGE PLATE IDENTIFYING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW OF GDOT BRIDGE NO. 027-00268X-00678N BRIDGE PLATE IDENTIFYING COUNTY COMMISSIONERS AT THE TIME OF CONSTRUCTION. - GDOT Bridge No. 027-00268X-00678N, County Road 268-Empress Road span Piscola Creek, Quitman, Brooks County, GA

  1. Load Testing of an FRP Bridge Deck on a Truss Bridge

    Microsoft Academic Search

    Sreenivas Alampalli; Jonathan Kunin

    2003-01-01

    New York State has constructed a fiber reinforced polymer (FRP) bridge deck as an experimental project. The goal of the project was to improve the load rating of a 50-yr old truss bridge located in Wellsburg, New York. The FRP deck weighs approximately 80-percent less than the deteriorated concrete bridge deck it replaced. Reducing the dead load increased the allowable

  2. Bridge over little Pine Creek (S.R. 1026, section 002 bridge) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bridge over little Pine Creek (S.R. 1026, section 002 bridge) looking west across traffic level - Bridge over Little Pine Creek, State Route 1026 over Little Pine Creek, 2.01 kilometers (1.25 miles) East of Bendertown, Jonestown, Columbia County, PA

  3. Bridge over little Pine Creek (S.R. 1026, section 002 bridge) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bridge over little Pine Creek (S.R. 1026, section 002 bridge) looking north-northeast across traffic level - Bridge over Little Pine Creek, State Route 1026 over Little Pine Creek, 2.01 kilometers (1.25 miles) East of Bendertown, Jonestown, Columbia County, PA

  4. FBG bending gauge on bridges: an effort towards standardization of bridge structural health monitoring

    Microsoft Academic Search

    I.-Wen Wu; Chung-Yue Wang; Ming-Hung Chen; Hao-Lin Wang; Allen Cheng; Patrick Tsai; David Wu; Hung-Wei ChangChien; Hentai Shang

    2007-01-01

    The FBG bending gauge developed by POFC is applied in several situations involving bridge safety\\/health monitoring. Under static loading conditions, the FBG bending gauge serves as an excellent tool to deduce an overall deflection curve on the bridge section under study. The gauge also works well in dynamic situations where instantaneous vertical deflections of bridge structures resulting from a cruising

  5. Bridge afflux analysis through arched bridge constrictions using artificial intelligence methods

    Microsoft Academic Search

    Mustafa Mamak; Galip Seckin; Murat Cobaner; Ozgur Kisi

    2009-01-01

    Although many studies have been carried out for estimating the afflux through modern straight deck bridge constrictions, little attention has been given to medieval arched bridge constrictions. Hydraulic Research Wallingford in the UK (Brown, P.M., 1988. Afflux at arch bridges. Report SR 182. Wallingford, UK: HR Wallingford) recently published a major coverage of both experimental and field afflux data obtained

  6. Synthesis, Structure, Bridge-Terminal Exchange Kinetics, and Molecular Orbital Calculations of Pyrazolate-Bridged Digallium Complexes Containing

    E-print Network

    Schlegel, H. Bernhard

    of Pyrazolate-Bridged Digallium Complexes Containing Bridging Phenyl Groups Chatu T. Sirimanne, John E. Knox in the solid state with two bridging phenyl groups,2a while triphenylgallium is a monomer in the solid state.7 bridging phenyl ligands. The observation of bridging phenyl ligands in these complexes is particularly

  7. Salt-Bridge Energetics in Halophilic Proteins

    PubMed Central

    Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K.

    2014-01-01

    Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are ?3.0 kcal mol?1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of ?5.0 kcal mol?1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (?10 kcal mol?1) exceeds than that of bridge term (?7 kcal mol?1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its specific electrostatic interactions which we hope would help in protein engineering and bioinformatics studies. PMID:24743799

  8. The Bridge of Mandolin County

    NASA Astrophysics Data System (ADS)

    Lantz, Juliette M.; Feindt, Jenny E.; Lewellyn, Eric P. B.; Walczak, Mary M.

    1999-12-01

    The Bridge of Mandolin County is a case designed to teach the general chemistry principles of molar mass, ions and aqueous reactions, solubility rules, and inorganic nomenclature. Through the instructor-facilitated class discussion, students consider the options before the Mandolin Town Council regarding deicing the newly constructed bridge connecting Mandolin with a large nearby city. The students must decipher contradictory claims made on behalf of sodium chloride, the traditional deicer, and calcium magnesium acetate, a new environmentally friendly deicer, to arrive at the most cost-effective and environmentally appropriate deicing product. As they work through the analysis they raise questions that can be addressed in a laboratory setting. Four optional role-playing experiments are included, which can be used by the students to gather information helpful to resolution of the case. The case is intended to be used over two class periods, with a laboratory period in between, though suggestions for other models are provided. Laboratory procedures include an EDTA titration for Ca2+ and Mg2+, a gravimetric analysis, a qualitative examination of ions and solubility, an introduction to freezing point depression and measurement, and an experimental design activity. This case can also successfully be used without alteration in non-majors chemistry or environmental chemistry courses, or upper-level analytical or environmental chemistry courses.

  9. 10. LOOKING EAST OHIO END OF BRIDGE AS VIEWED FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. LOOKING EAST OHIO END OF BRIDGE AS VIEWED FROM PROPOSED CENTERLINE OF NEW BRIDGE APPROACH UNDER ELEVATED OHIO 7 - Bridgeport Bridge, Spanning West Channel of Ohio River, U.S. Route 40, Wheeling, Ohio County, WV

  10. 23 CFR 650.807 - Bridges requiring a USCG permit.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.807 Bridges...at the appropriate level by FHWA for structural concepts, hydraulics, and navigational clearances prior to submission of the...

  11. 23 CFR 650.807 - Bridges requiring a USCG permit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.807 Bridges...at the appropriate level by FHWA for structural concepts, hydraulics, and navigational clearances prior to submission of the...

  12. 23 CFR 650.705 - Application for discretionary bridge funds.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650.705 Application for discretionary bridge funds. Each year...

  13. 23 CFR 650.807 - Bridges requiring a USCG permit.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.807 Bridges...at the appropriate level by FHWA for structural concepts, hydraulics, and navigational clearances prior to submission of the...

  14. 23 CFR 650.705 - Application for discretionary bridge funds.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650.705 Application for discretionary bridge funds. Each year...

  15. 23 CFR 650.705 - Application for discretionary bridge funds.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650.705 Application for discretionary bridge funds. Each year...

  16. 23 CFR 650.705 - Application for discretionary bridge funds.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650.705 Application for discretionary bridge funds. Each year...

  17. 12. ELEVATION VIEW UNDERNEATH BRIDGE, SHOWING FOUR BEAMS RESTING ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. ELEVATION VIEW UNDERNEATH BRIDGE, SHOWING FOUR BEAMS RESTING ON PILASTERS AT WEST END OF BRIDGE - North Twenty-First Street Bridge, North Twenty-first Street spanning Buckley Gulch, Tacoma, Pierce County, WA

  18. 10. Detail of bridge underside showing gears for locking mechanism ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Detail of bridge underside showing gears for locking mechanism at south end of bridge. View to east. - Locke Avenue Bridge, Locke Avenue (County Route 671) Spanning Raccoon Creek, Swedesboro, Gloucester County, NJ

  19. 2. GENERAL VIEW OF BRIDGE FROM ROADBED WITH 4' RANGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW OF BRIDGE FROM ROADBED WITH 4' RANGE POLE NEAR NORTHWEST CORNER OF BRIDGE, LOOKING SOUTH - North Fork Bridge, Spans North Fork of White River at State Highway 5, Norfork, Baxter County, AR

  20. 12. Interior detail of bridge operator's house showing generator and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Interior detail of bridge operator's house showing generator and bridge operator, Mr. Gene Amonette, facing west. - Palm Valley Bridge, County Road 210 spanning Intracoastal Waterway, Ponte Vedra Beach, St. Johns County, FL