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

An integrated flyback converter for DC uninterruptible power supply  

Microsoft Academic Search

An integrated flyback power converter performing the combined functions of uninterruptible power supply (UPS) and switch-mode power supply (SMPS) is presented. This power converter has a high voltage main power input and a low voltage backup battery input. DC output is obtained from the main input via a flyback power converter during normal operation and from the backup battery via

Kwok-Wai Ma; Yim-Shu Lee

1996-01-01

2

An integrated flyback converter for DC uninterruptible power supply  

Microsoft Academic Search

An integrated flyback power converter performing the combined functions of uninterruptible power supply (UPS) and switch-mode power supply (SMPS) is presented. This power converter has a high voltage main power input and a low voltage backup battery input. DC output is obtained from the main input via a flyback power converter during normal operation, and from the backup battery via

Kwok-Wai Ma; Yim-Shu Lee

1994-01-01

3

Active Clamp Flyback Converter Combined with Dither Voltage Generator for Poultry Stunning Applications  

Microsoft Academic Search

This paper presents an intelligent poultry stunner with parameter auto-tuning feature for improving carcass quality and animal welfare. In this stunner system, an active clamp flyback converter is used to increase conversion efficiency, and a dither voltage generator realized with a half-bridge inverter is adopted to fast breakdown the skin impedance of the poultry which can reduce poultry stress and

S.-Y. Tseng; T.-F. Wu; Z.-Y. Chang; J.-S. Hu; Y.-D. Chang

2006-01-01

4

Active clamp flyback converter with current sharing scheme for multi-channel poultry stunning applications  

Microsoft Academic Search

This paper presents an intelligent poultry stunner with a current sharing controller for improving carcass quality and animal welfare. In this circuit structure, a stunner which is composed of active clamp flyback converter and full-bridge inverter, and a dither voltage generator which is adopted to fast breakdown the skin impedance of the poultry for reducing poultry stress and improving carcass

S.-Y. Tseng; C.-T. Hsieh; Y.-H. Su

2008-01-01

5

An integrated flyback converter for DC uninterruptible power supply  

SciTech Connect

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.

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

6

Flyback Transformer Based Transient Suppression Method for Digitally Controlled Buck Converters  

E-print Network

] and extra switches, which considerably increases cost and consumes PCB real estate. A single phase voltageFlyback Transformer Based Transient Suppression Method for Digitally Controlled Buck Converters-- A current-programmed mode (CPM) digitally controlled buck converter with a flyback transformer is proposed

Prodiæ, Aleksandar

7

Active Clamp Interleaved Flyback Converter with Single-Capacitor Turn-off Snubber for Stunning Poultry Applications  

Microsoft Academic Search

The paper proposes an active clamp interleaved flyback converter with a single-capacitor turn-off snubber associated with a full-bridge inverter for stunning poultry applications. The proposed converter can use active clamp circuit to recover the energy of transformer and to achieve zero-voltage switching at turn-on transition. In addition, the proposed one adopts a single-capacitor snubber not only to smooth out switch

S.-Y. Tseng; C.-T. Hsieh; H.-C. Lin

2007-01-01

8

Development of an isolated flyback converter employing boundary-mode operation and magnetic flux sensing feedback  

E-print Network

This thesis focuses on the marriage of magnetic-flux-sensing feedback and boundary-mode operation in a flyback converter to create a simple, small, low-cost, isolated, and tightly regulated power supply. Although each ...

Kenia, Mayur V. (Mayur Vasant), 1981-

2004-01-01

9

Microbial fuel cell energy harvesting using synchronous flyback converter  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

10

A stability issue with current mode control flyback converter driving LEDs  

Microsoft Academic Search

Use of LED lamp for lighting becomes common and power converter for LEDs is critical. This paper is about the design of stable power converter for LED lamp. In the construction of the converter, flyback topology is used together with current-controlled current mode control. LED is a current driven device with low dynamic resistance. This introduces instability to output feedback.

H. M. Pang; P. M. H. Bryan

2009-01-01

11

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

E-print Network

SPC-08-07 16 Development of Electrolytic-Capacitor-Less Ultra-Thin Flyback Converter Shintaro, flyback converter, electrolytic capacitor, ultra-thin transformer) 1 EL CCFL LED DC/DC 2 Co., Ltd.) Abstract This paper describes two novel approaches to develop an ultra-thin switching

Fujimoto, Hiroshi

12

RC-RCD clamp circuit for ringing losses reduction in a flyback converter  

Microsoft Academic Search

An RCD clamp circuit is usually used in flyback converters, in order to limit the voltage spikes caused by leakage transformer inductance. Oscillation ringing appears due to the clamp diode, which deteriorates the converter's power rate. This brief describes this ringing phenomenon and the use of an RC-RCD clamp circuit for damping the clamp diode's oscillation. This clamp circuit is

Alenka Hren; Joze Korelic; Miro Milanovic

2006-01-01

13

Planar LTCC transformers for high voltage flyback converters.  

SciTech Connect

This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstrated LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.

Schofield, Daryl (NASCENT Technology Inc. , Watertown, SD); Schare, Joshua M.; Glass, Sarah Jill; Roesler, Alexander William; Ewsuk, Kevin Gregory; Slama, George (NASCENT Technology Inc. , Watertown, SD); Abel, Dave (NASCENT Technology Inc. , Watertown, SD)

2007-06-01

14

Interleaved flyback converter with turn-on\\/off snubber for poultry stunning applications  

Microsoft Academic Search

This paper proposes an interleaved flyback converter with a novel L-C-D snubber to reduce turn-on and turn-off losses. The proposed L-C-D snubber is composed of a single capacitor to form turn-off snubber, and an inductor and a diode connected in parallel to form turn-on snubber. In this circuit structure, the turn-off snubber is used to limit rising rate of drain-source

S.-Y. Tseng; C.-T. Hsieh; C.-M. Yang

2008-01-01

15

High speed cascode flyback converter using multilayered coreless printed circuit board (PCB) step-down power transformer  

Microsoft Academic Search

In this paper, design and analysis of the high speed isolated cascode flyback converter using multilayered coreless PCB step down power transformer is presented. The converter is tested for the input voltage variation of 60- 120V with a nominal DC input voltage of 90V. The designed converter was simulated and tested successfully up to the output power level of 30W

Hari Babu Kotte; Radhika Ambatipudi; Kent Bertilsson

2011-01-01

16

Coupled Dual Interleaved Flyback Converter for High Input Voltage Application  

E-print Network

- This paper proposes an integrated magnetic DC-DC converter suitable for high input voltage application electronics. For large step-down power conversions, such as 48V to 1V, buck mode isolated topologies have or EE core is used for all the magnetic components, including the input inductor, the step-down

Lehman, Brad

17

A Three-Phase Unity Power Factor Single-Stage AC–DC Converter Based on an Interleaved Flyback Topology  

Microsoft Academic Search

This paper presents the design and implementation of a three-phase unity-power-factor single-stage ac-dc converter based on an interleaved flyback topology. The primary market target of the converter is within the telecommunications industry where it supplies high-quality dc power to the telecom loads and performs high-capacity battery charging while providing zero har- monic emission and unity power factor to the utility

Bunyamin Tamyurek; David A. Torrey

2011-01-01

18

A Universal-Input Single-Stag2e High-Power-Factor Power Supply for HB-LEDs Based on Integrated Buck–Flyback Converter  

Microsoft Academic Search

Due to the high rise in luminous efficiency that high- brightness light-emitting diodes (HB-LEDs) have experienced in recent years, many new applications have been researched. This paper covers a streetlight LED application using the offline in- tegrated buck-flyback converter (IBFC) developed in previous works. In this application, the converter is used to provide power- factor correction from a universal ac

David Gacio; J. Marcos Alonso; Antonio J. Calleja; Jorge Garcia; Manuel Rico-Secades

2011-01-01

19

Hierarchical Control of Bridge-of-Bridge Multilevel Power Converters  

Microsoft Academic Search

Multilevel converters are among the members of the family of power-converter topologies for realizing higher power levels and better waveform quality. In addition to the established topologies of neutral-point-clamped three-level and cascaded H-bridge converters, novel topologies that offer attractive features, such as ease of modularity and functionality, continue to be introduced. Among these, the bridge-of-bridge multilevel converters have the potential

Dan C. Ludois; Justin K. Reed; Giri Venkataramanan

2010-01-01

20

High Efficiency Single Output ZVS-ZCS Voltage Doubled Flyback Converter  

NASA Astrophysics Data System (ADS)

A switch operating at high switching frequency increases the switching losses of the converter resulting in lesser efficiency. Hence this paper proposes a new topology which has resonant switches [zero voltage switching (ZVS)] in the primary circuit to eliminate the above said disadvantages, and voltage doubler zero current switching (ZCS) circuit in the secondary to double the output voltage, and hence the output power, power density and efficiency. The design aspects of the proposed topology for a single output of 5 V at 50 kHz, its simulation and hardware results are discussed in detail. The analysis of the results obtained from a 2.5 W converter reveals the superiority of the proposed converter.

Kaliyaperumal, Deepa; Saju, Hridya Merin; Kumar, M. Vijaya

2014-12-01

21

Control of H-bridge based multilevel converters  

Microsoft Academic Search

Multilevel converters are suitable for high voltage and high power applications. Among them H-bridge ones have encountered good success due to their simpler layout and the reduced number of components over the counterparts. H-bridge multilevel converters used as active rectifiers represent an attractive solution in traction systems due to the possibility to reduce the AC filter size and to boost

A. Dell'Aquila; V. G. Monopoli; M. Liserre

2002-01-01

22

Decentralized control of a cascaded H-Bridge multilevel converter  

Microsoft Academic Search

Despite its inherently modular hardware structure, the control system of most cascaded H-bridge converters is usually highly centralized, and relies on a high bandwidth intra- converter communication system to transmit time critical control signals to the module controllers. In contrast, this paper presents a decentralized control strategy for a modular cascaded converter, where each module controller determines its own switching

W. Y. Kong; D. G. Holmes; B. P. McGrath

2011-01-01

23

Modulation Extension Control of Hybrid Cascaded H-bridge Multilevel Converters with 7-level  

E-print Network

Modulation Extension Control of Hybrid Cascaded H-bridge Multilevel Converters with 7-level control algorithm for hybrid cascaded H-bridge multilevel converters. The hybrid cascaded H-bridge the modulation index range of the hybrid cascaded H-bridge multilevel converters. I. INTRODUCTION The multilevel

Tolbert, Leon M.

24

Cycling firing method for bypass operation of bridge converters  

DOEpatents

The bridge converter comprises a number of switching elements and an electronic logic system which regulated the electric power levels by controlling the firing, i.e., the initiation of the conduction period of the switching elements. Cyclic firing of said elements allows the direct current to bypass the alternating current system with high power factor and negligible losses.

Zabar, Zivan (99-72 66th Rd., Apt. 9N, Forest Hills, NY 11375)

1982-01-01

25

Ac-Ac Dual Active Bridge Converter for Solid State Transformer  

E-print Network

converters as distribution transformers [1]. A power electronics-based solid state transformer (SST) providesAc-Ac Dual Active Bridge Converter for Solid State Transformer Hengsi Qin and Jonathan W. Kimball--Solid State Transformer, Dual Active Bridge Converter, Ac-Ac Converter, Zero Voltage Switching I. INTRODUCTION

Kimball, Jonathan W.

26

SHE-PWM control for asymmetrical hybrid multilevel flying capacitor and H-bridge converter  

Microsoft Academic Search

This paper presents a new asymmetrical hybrid voltage source multilevel converter controlled with selective harmonic elimination pulse width modulation (SHE-PWM) technique. The proposed hybrid multilevel converter combines the separate flying capacitor (FC) converter in series with an H-bridge converter with distinct DC voltage supply. The DC-link voltage of the FC is twice that of the H-bridge converter and the flying

Mohamed S. A. Dahidah; Georgios S. Konstantinou; Vassilios G. Agelidis

2011-01-01

27

DC bus ripple minimization in cascaded H-bridge multilevel converters under staircase modulation  

Microsoft Academic Search

Cascade connected H bridge multilevel converters are becoming an attractive topology for very high power applications. Due the single phase loading of the individual bridges, the DC link capacitors required in these converters are faced with a heavy stress. The problem is particularly acute with stair-case type modulation strategies. This paper presents an approach for equalizing the power drawn from

Yusuke Fukuta; Giri Venkataramanan

2002-01-01

28

Multiple output of dual half bridge LLC resonant converter using PFM-PD control  

Microsoft Academic Search

This paper proposes the multiple output of dual half bridge LLC resonant converter using PFM-PD control. For the main output, dual half bridge LLC resonant converter controlled by pulse frequency modulation (PFM) is used. For the sub output, multiple outputs scheme is configured and operated by phase delay (PD) control. Since the control variables, PFM and PD, have little mutual

Byeong Cheol Hyeon; Bo Hyung Cho

2009-01-01

29

Ac-ac dual active bridge converter for solid state transformer  

Microsoft Academic Search

This work investigates the application of an ac-ac dual active bridge converter for solid state transformer. The proposed converter topology consists of two active H-bridges and one high frequency transformer. Four-quadrant switch cells are used to ensure bi-directional power flow. The advantages of direct ac-ac conversion include fewer power conversion stages and minimized passive components. The ac-ac dual active bridge

Hengsi Qin; Jonathan W. Kimball

2009-01-01

30

Investigation on Capacitor Voltage Regulation in Cascaded H-Bridge Multilevel Converters With Fundamental Frequency Switching  

Microsoft Academic Search

Multilevel power electronic converters have gained popularity in high-power applications due to their lower switch voltage stress and modularity. Cascaded H-bridge converters are a promising breed of multilevel converters which generally require several separate dc voltage sources. By utilizing the redundant switching states, it is possible to replace the separate dc voltage sources with capacitors and keep only the one

Hossein Sepahvand; Jingsheng Liao; Mehdi Ferdowsi

2011-01-01

31

Power conditioning system with cascaded H-bridge multilevel converter — DC-link voltage balancing method  

Microsoft Academic Search

Multilevel converters have become an attractive choice for high voltage and high power applications. One of the most popular multilevel converter topologies is the cascaded H-bridge converter. Besides its simplicity this topology requires separate DC sources. In electric drive applications these DC sources are normally performed by multi-winding transformers with diode rectifiers. In STATCOM or PWM rectifiers there is no

Marcin Zygmanowski; Boguslaw Grzesik; Jaroslaw Michalak

2011-01-01

32

Design and implementation of LLC resonant half bridge converter  

Microsoft Academic Search

LLC resonant converter is proposed for Front End DC\\/DC conversion application. Three advantages are achieved with this resonant converter. First, ZVS turn on and low current turn off of MOSFETs is achieved. The switching loss is reduced so we can operate the converter at higher switching frequency. Second advantage is that with this topology, we can optimize the converter at

L. Sahaya Senthamil; P. Ponvasanth; V. Rajasekaran

2012-01-01

33

Integrated magnetic for hybrid full-bridge three-level LLC resonant converter  

Microsoft Academic Search

A novel hybrid full-bridge (H-FB) three-level (TL) LLC resonant converter with integrated magnetics (IM) is proposed in this paper, it integrates the advantages of the TL converter and the LLC resonant converter, which is very suitable for wide-input-voltage-range applications, such as fuel cell power systems, or high input voltage applications, i.e. HV input converters in wind power system. With magnetic

Koulin Wu; Qianhong Chen; Ke Jin; Xinbo Ruan

2008-01-01

34

Design of a cascaded H-bridge converter for insulation testing  

Microsoft Academic Search

This paper describes a design of a cascaded H-bridge converter for insulation testing of the crosslinked polyethylene (XLPE) cable. This high voltage generator produces a sinusoidal waveform at a very low frequency (VLF) of 0.1 Hz. The design of the cascaded H-bridge converter consists of two main parts, a modulation unit and a switching unit. The modulation unit compares the

W. Kongnun; A. Sangswang; S. Chotigo

2009-01-01

35

Feasibility of capacitor voltage regulation and output voltage harmonic minimization in cascaded H-bridge converters  

Microsoft Academic Search

Multilevel converters have found popularity in electric-drive vehicles. In cascaded H-bridge multilevel converters, it is advantageous to use only one DC voltage source for the main H-bridge cell and supply the rest of the cells with capacitors. However, regulating the capacitors' voltage level becomes a challenging issue. This paper studies the existing constraints on regulating the capacitor voltage levels especially

Hossein Sepahvand; Mostafa Khazarei; Mehdi Ferdowsi; Keith Corzine

2010-01-01

36

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

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

Yu Chen; Xuejun Pei; Li Peng; Yong Kang

2010-01-01

37

A normalized model for the half-bridge series resonant converter  

NASA Technical Reports Server (NTRS)

Closed-form steady-state equations are derived for the half-bridge series resonant converter with a rectified (dc) load. Normalized curves for various currents and voltages are then plotted as a function of the circuit parameters. Experimental results based on a 10-kHz converter are presented for comparison with the calculations.

King, R.; Stuart, T. A.

1981-01-01

38

Quick identification technique of fault conditions in cascaded H-Bridge multilevel converters  

Microsoft Academic Search

With reference to multilevel converters in cascaded H-bridge configuration, the paper presents a technique suitable to quickly identify fault conditions during normal operations. First a modulation technique generalized to m-level converters is synthetically illustrated in order to evidence the presence of different modulation patterns and the corresponding criteria of selection in normal operating conditions. Then, all the \\

G. Brando; A. Dannier; A. Del Pizzo; R. Rizzo

2007-01-01

39

Cascaded H-bridge multilevel converter multistring topology for large scale photovoltaic systems  

Microsoft Academic Search

Large scale grid connected photovoltaic (PV) energy conversion systems have reached the megawatt level. This imposes new challenges on existing grid interface converter topologies and opens new opportunities to be explored. In this paper a new medium voltage multilevel-multistring configuration is introduced based on a three-phase cascaded H-bridge (CHB) converter and multiple string dc-dc converters. The proposed configuration enables a

S. Rivera; S. Kouro; B. Wu; J. I. Leon; J. Rodriguez; L. G. Franquelo

2011-01-01

40

A self oscillated half bridge converter using impulse resonant soft-switching  

Microsoft Academic Search

A novel circuit of DC-TO-DC converter for the battery charger of telecommunication equipment is proposed. For the circuit, a novel self oscillated half-bridge converter with an impulse resonant soft-switching using saturating inductance of the oscillator is developed. In this converter, the self oscillated frequency control circuit has the switches operated soft-switching by impulse charging and discharging the parasitic capacitance of

H. Sakamoto; K. Harada; C. H. Kang; Y. Matsuda; H. J. Kim

2002-01-01

41

Full Bridge-full Wave Mode Three-level AC\\/AC Converter with High Frequency Link  

Microsoft Academic Search

At present, the primary methods of realizing AC\\/AC voltage transformation are frequency transformer, AC-DC-AC converter, matrix converter, high-frequency link AC\\/AC converters and single-stage AC\\/AC converters. In areas of high power conversion, taking into account to converter's cost and the quality of output voltage, bridge mode AC\\/AC converter has some advantages. This converter can realize electrical isolation, high input power factor

Kaiming Yang; Lei Li

2009-01-01

42

A Hybrid Driving Scheme for Full-Bridge Synchronous Rectifier in LLC Resonant Converter  

Microsoft Academic Search

The LLC resonant converter with a full-bridge rectifier can achieve two balanced outputs with a simple balancing capacitor, which is quite attractive for LED driver application. To further improve the efficiency, synchronous rectification is an effective way to reduce the conduction loss of the rectifier. In this paper, a new hybrid driving scheme for full-bridge-type synchronous rectifier (SR) in LLC

Junming Zhang; Jianfeng Wang; Guoxing Zhang; Zhaoming Qian

2012-01-01

43

A new control method for single-dc-source cascaded H-bridge multilevel converters using phase-shift modulation  

Microsoft Academic Search

Multilevel converters have gained popularity in high-power applications due to their low switch voltage stress and modularity. Cascaded H-bridge converters are a promising breed of multilevel converters, which generally require several independent dc sources. Using phase-shift modulation, a new control method for cascaded H-bridge multilevel converters with only one independent dc source per phase is presented in this paper. Unlike

Jingsheng Liao; Keith Corzine; Mehdi Ferdowsi

2008-01-01

44

A Novel PWM Modulation Strategy for DC Voltage Balancing in Cascaded H-Bridge Multilevel Converters  

Microsoft Academic Search

This paper presents a novel Voltage Balancing PWM modulation strategy for Cascaded H-Bridge multilevel converters. These converters have been classically commu-tated at fundamental line-frequencies, but the evolution of Power Semiconductors has allowed to increase switching frequencies and the power ratings of these devices, permitting the use of PWM modulation techniques. This paper presents a new PWM modulation strategy that solves

Jon Andoni Barrena; Luis Marroyo; M. A. Rodriguez; J. R. Torrealday

2007-01-01

45

Control of a cascaded H-bridge multilevel converter for grid connection of photovoltaic systems  

Microsoft Academic Search

In this paper a control method for cascaded H-bridge multilevel converters for grid connection of photovoltaic systems is analyzed. The use of the multilevel converter introduces a series of advantages: improved power quality (lower current ripple), smaller filters, reduced switching frequency, no need of boost dc-dc stage and possible elimination of step-up transformer, all of which have a positive impact

Samir Kouro; Bin Wu; Álvaro Moya; Elena Villanueva; Pablo Correa; José Rodríguez

2009-01-01

46

Full bridge DC-DC converter with zero voltage resonant transition switching and immersion cooling  

Microsoft Academic Search

A full-bridge topology was used to implement a family of DC-DC power converters which operate with zero voltage resonant transition (ZVRT) switching and a modified pulse width modulation technique at nominal output voltages ranging from 2.0 to 6.0 V DC at full load currents ranging from 1400 to 1000 A DC. Liquid-immersion cooling was used. The converter was packaged in

C. P. Henze

1992-01-01

47

A Sensorless Control of H-bridge Multilevel Converter for Maximum Power Point Tracking in Grid Connected Photovoltaic Systems  

Microsoft Academic Search

There is a high development of grid-connected photovoltaic systems that utilize static converter which influence the efficiency of the system. The energy conversion depends on the architecture of the converter, different solutions are available and H-bridge multilevel converters seem to be an optimal solution also for the power quality. It is important to utilize a proper architecture of converter but

G. Brando; A. Dannier; R. Rizzo

2007-01-01

48

A high step-up, non-isolated DC-DC converter with reduced repeated power processing  

Microsoft Academic Search

This paper proposes a non-isolated converter that is based on a flyback topology. The proposed converter has high conversion ratio and achieves higher efficiency with reduced voltage and current stresses on the power semiconductors when compared to the conventional flyback converter. Analysis and key converter operating waveforms are reported in the paper. Experimental results taken from a 60 W laboratory

Dylan D. C. Lu; Grace M. L. Chu; Vassilios G. Agelidis

2010-01-01

49

Asymmetrical DC voltage regulation for a STATCOM based on H-bridge multi-cell converter  

Microsoft Academic Search

One of the main problems when H-bridge multilevel converter is used for compensating reactive power is the DC link regulation; this is because of different losses into each cell. In this paper a DC link regulation strategy is obtained through a power analysis. It is shown how the strategy can be applied as much an asymmetric as a symmetric multilevel

Javier Pérez-Ramírez; Víctor Cárdenas; Homero Miranda

2010-01-01

50

PWM rectifier in power cell of cascaded H-bridge multilevel converter  

Microsoft Academic Search

This paper proposes to use PWM rectifier to replace the diode rectifier in the cascaded H-bridge multilevel converter in order to regenerate the power from the load to the grid. The rectifier in this paper employs the leakage reactance of the secondary windings of the input transformer instead of physical reactor because of the large number of the reactors needed

Jian Wang; Yongdong Li

2007-01-01

51

Design of half-bridge LLC resonant converter based on PLC810PG  

Microsoft Academic Search

In order to improve the power density of switching power supply, reduce the EMI and conduction losses of the power switching device, a half-bridge LLC resonant converter based on PLC810PG is introduced. Its series resonant network consists of resonant capacitor and resonant inductor and magnetic excited inductor, which makes its switches in the primary side work in zero voltage switching

Ludan Ma; Jianren Hu; Huibin Qin

2011-01-01

52

Series transistors isolate amplifier from flyback voltage  

NASA Technical Reports Server (NTRS)

Circuit enables high sawtooth currents to be passed through a deflection coil and isolate the coil driving amplifier from the flyback voltage. It incorporates a switch consisting of transistors in series with the driving amplifier and deflection coil. The switch disconnects the deflection coil from the amplifier during the retrace time.

Banks, W.

1967-01-01

53

Predictive control of a grid-connected cascaded H-bridge multilevel converter  

Microsoft Academic Search

A predictive control scheme for a three-phase cascaded h-bridge rectifier is presented. The main objectives of this control scheme is to minimize the error between the input active and reactive power and their references, and to balance the dc-link capacitor voltages. These objectives are expressed as a cost function to be minimized. A model of the converter is used for

Patricio Cortes; Francisco Quiroz; Jose Rodriguez

2011-01-01

54

A modular power electronic transformer based on a cascaded H-bridge multilevel converter  

Microsoft Academic Search

In this paper a modular power electronic transformer (PET) for feeding critical loads is presented. The PE-based transformer is a multi-cellular step-down converter that can directly connect to medium voltage levels on the primary side and provide a low voltage, highly stable interface for consumer applications. The presented structure consists of three stages: a cascaded H-bridge (CHB) rectifier, an isolation

H. Iman-Eini; Sh. Farhangi; J.-L. Schanen; M. Khakbazan-Fard

2009-01-01

55

Design of Power Electronic Transformer based on Cascaded H-bridge Multilevel Converter  

Microsoft Academic Search

One key component of the future automation in electrical network is the replacement of conventional distribution transformers by an all-solid-state (power- electronic) alternative. In this paper, the optimum design of a power electronic transformer (PET) based on state of the art cascaded H-bridge multilevel converter is investigated. In the design process, a new and simple control method for balancing the

H. Iman-Eini; Sh. Farhangi; J.-L. Schanen; J. Aime

2007-01-01

56

Fault-Tolerant Design and Control Strategy for Cascaded H-Bridge Multilevel Converter-Based STATCOM  

Microsoft Academic Search

Cascaded H-bridge multilevel converter (CHMC) is a promising topology for flexible ac transmission systems such as static synchronous compensator (STATCOM) applications. Attention was drawn to the issue of converter reliability due to the large number of power devices used in CHMC applications. This paper proposed an effective fault-tolerant strategy by using H-bridge building block (HBBB) redundancy in CHMC-based STATCOM. The

Wenchao Song; Alex Q. Huang

2010-01-01

57

Modulation Extension Control of Hybrid Cascaded H-bridge Multilevel Converters with 7-level Fundamental Frequency Switching Scheme  

Microsoft Academic Search

This paper presents a modulation extension control algorithm for hybrid cascaded H-bridge multilevel converters. The hybrid cascaded H-bridge multilevel motor drive using only a single DC source for each phase is promising for high power motor drive applications since it can greatly decrease the number of required DC power supplies, has high quality output power due to its high number

Zhong Du; Burak Ozpineci; Leon M. Tolbert

2007-01-01

58

Development of a digital solar simulator based on full-bridge converter  

NASA Astrophysics Data System (ADS)

With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.

Liu, Chen; Feng, Jian; Liu, Zhilong; Tong, Weichao; Ji, Yibo

2014-02-01

59

PWM Resonant Single-Switch Isolated Converter  

Microsoft Academic Search

The flyback converter is one of the most attractive isolated converters in small power applications because of its simple structure. However, it suffers from a high device stress and a large transformer size. To relieve these drawbacks, a high-efficient pulsewidth modulation resonant single-switch isolated converter is proposed. The proposed converter derives the power using the resonance between transformer leakage inductor

Ki-Bum Park; Chong-Eun Kim; Gun-Woo Moon; Myung-Joong Youn

2009-01-01

60

Dynamic analysis and optimal design of high efficiency full bridge LLC resonant converter for server power system  

Microsoft Academic Search

In this paper, high efficiency full bridge LLC resonant converter for server power system is introduced. LLC resonant converter was reported in many papers recently because of its simple structure, high efficiency and high switching frequency ability. However, many SMPS designers and field engineers still encounter technical difficulties of power stage design and control scheme due to environmental regulations of

Minjae Joung; Hosung Kim; Joowon Baek

2012-01-01

61

A new control strategy for cascaded H-bridge multilevel converter to operate as a D-STATCOM  

Microsoft Academic Search

In this paper, an indirect current control method is proposed for cascaded H-bridge-based multilevel converter to operate as a STATCOM. As the indirect control approach does not need any current sensor, the system reliability increases. Using the proposed control strategy, dc link voltages are balanced, although the H-bridge cells have different amounts of losses. The reactive power is also equally

A. Marzoughi; H. Imaneini

2012-01-01

62

Modulation Extension Control of Hybrid Cascaded H-bridge Multilevel Converters with 7-level Fund mental Frequency Switching Scheme  

Microsoft Academic Search

This paper presents a modulation extension control al- gorithm for hybrid cascaded H-bridge multilevel converters. The hybrid cascaded H-bridge multilevel motor drive using only a single dc source for each phase is promising for high-power mo- tor drive applications since it can greatly decrease the number of required dc power supplies, has high-quality output power be- cause of its high

Zhong Du; Burak Ozpineci; Leon M. Tolbert

2009-01-01

63

Energy-Sampled Data Modeling of a Cascade H-Bridge Multilevel Converter for Grid-connected PV Systems  

Microsoft Academic Search

This paper presents an energy-sampled data model of a cascade H-bridge multilevel converter for single-phase multi-string grid-connected photovoltaic systems. Based on this model a control scheme for the power converter is obtained. The achievement of the DC-AC conversion with an efficient PV energy extraction, low harmonic distortion and output unity power factor is validated with simulation results

J. J. Negroni; F. Guinjoan; C. Meza; D. Biel; P. Sanchis

2006-01-01

64

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

SciTech Connect

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.

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

2009-05-07

65

Bridges  

MedlinePLUS

... is made to replace one or more missing teeth. Bridges can be supported in any of three ways: ... The dentist may also make impressions of the teeth. The bridge is placed at later visits. On average, bridges ...

66

Bridges  

NSDL National Science Digital Library

Bridges come in a wide variety of sizes, shapes, and lengths and are found all over the world. It is important that bridges are strong so they are safe to cross. Design and build a your own model bridge. Test your bridge for strength using a force sensor that measures how hard you pull on your bridge. By observing a graph of the force, determine the amount of force needed to make your bridge collapse.

2012-07-19

67

Applications of soft-switching full-bridge converter and rotational electric field to transdermal drug delivery  

Microsoft Academic Search

This paper presents applications of a soft-switching full-bridge converter to generate pulsed voltage (PV) for exciting tissue, which includes transdermal drug delivery (TDD), transcutaneous electrical nerve stimulation, functional electrical stimulation, etc. Particularly, in TDD it offers many potential advantages over conventional methods, such as oral and injection, and it avoids drug degradation through gastro-intestinal and liver. To design a portable

T.-F. Wu; S.-Y. Tseng; D.-S. Su; Y.-M. Chen; Y.-K. Chen

2004-01-01

68

A model-based controller for the cascade h-bridge multilevel converter used as a shunt active filter  

Microsoft Academic Search

This paper presents the modeling and control processes of the cascade h-bridge multilevel converter used as a shunt active filter. The single-phase five-level topology is studied, however, it can be easily scaled to more levels. Based on the model, a controller is proposed to compensate harmonic distortion and reactive power due to a nonlinear load which is equivalent to guarantee

G. Escobar; M. F. Martinez-Montejano; P. R. Martinez-Rodriguez; M. Hernandez-Gomez

2006-01-01

69

Accurate Power Loss Model Derivation of a High-Current Dual Active Bridge Converter for an Automotive Application  

Microsoft Academic Search

An accurate power loss model for a high-efficiency dual active bridge converter, which provides a bidirectional electrical interface between a 12-V battery and a high-voltage (HV) dc bus in a fuel cell car, is derived. The nominal power is 2 kW, the HV dc bus varies between 240 and 450 V, and the battery voltage range is between 11 and

Florian Krismer; Johann W. Kolar

2010-01-01

70

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

Microsoft Academic Search

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

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

2008-01-01

71

Design and Implement of a High-Frequency Bridge Type AC-AC Direct Converter for Contactless Power Transfer Systems  

Microsoft Academic Search

\\u000a Focusing on the defects of traditional contactless power transfer systems with an AC-DC-AC power transition type, a high-frequency\\u000a bridge type bidirectional switch AC-AC direct converter was presented to generate the high-frequency current in the primary\\u000a circuit. Applying the principle of energy injection and free oscillation, the operating state of IGBTS were designed and the\\u000a high frequency current in the primary

Xiaomei Chen; Wangqiang Niu; Xiong Zhang

72

Cascaded H-bridge multilevel converter for grid connected photovoltaic generators with independent maximum power point tracking of each solar array  

Microsoft Academic Search

This paper introduces a new control method and proportional PWM modulation of the cascaded H-bridge multilevel converter for grid-connected photovoltaic systems. This control makes each H-bridge module supply different power levels, allowing therefore for each module an independent maximum power point tracking of the corresponding photovoltaic array.

O. Alonso; P. Sanchis; E. Gubia; L. Marroyo

2003-01-01

73

Inductor flyback characteristic gives voltage regulator fast response  

NASA Technical Reports Server (NTRS)

Voltage regulator alternately connects an inductor in parallel and in series with the input voltage source. This flyback voltage regulator provides a regulated dc voltage to varying loads from a varying dc supply and gives fast response to load and supply changes.

Smith, G. D.

1965-01-01

74

Bridges  

NSDL National Science Digital Library

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.

Leske, Cavin.

75

Distributed spectrum in full-bridge step-down converter with hysteresis current control  

Microsoft Academic Search

The Electromagnetic Interference (EMI) profile of DC-DC converters has an important influence on their operation in compatibility with other equipment. The EMI filter is designed for the DC-DC converter to attenuate the conducted EMI. The size of the EMI filter depends on the power of the conducted frequencies. The size of the EMI filter may reduce for EMI spectrum with

Samar Shahabi Ghahfarokhi; Neda Shahabi

2010-01-01

76

Bridges  

NSDL National Science Digital Library

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 typesâarch, beam, truss and suspensionâstudents 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.

Integrated Teaching And Learning Program

77

Efficiency study for a 150W LLC resonant converter  

Microsoft Academic Search

The paper presents and analyzes the efficiency of a 150 W LLC resonant converter in order to compare with the results obtained with a conventional 150 W flyback version. The experimental results of the LLC resonant converter show a maximum efficiency of 94%, and an efficiency of 92% under a full-load condition. Using the presented theoretical equations and design methods,

Chun-An Cheng; Hung-Wen Chen; En-Chih Chang; Chun-Hsien Yen; Kun-Jheng Lin

2009-01-01

78

Radiation effects on DC-DC Converters  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

79

H-bridge multilevel voltage source converter for direct grid connection of renewable energy systems  

Microsoft Academic Search

The conventional approach based on low-voltage converter with power frequency transformer is commonly employed for grid connection of offshore renewable power generation systems. Because of the heavy weight and large size of the transformer, the system can be expensive and complex for installation and maintenance. As an alternative approach to achieve a compact and light direct grid connection, a high-voltage

M. R. Islam; Y. G. Guo; J. G. Zhu

2011-01-01

80

Comparison of DC-bus voltage balancing strategies for three-phase DSTATCOM based on cascaded H-bridge multilevel converter  

Microsoft Academic Search

This paper presents a comparison of two DC-bus voltage balancing strategies for cascaded connected H-bridge converter-based STATCOMs. These converters have classically been commutated at fundamental line-frequencies, but the evolution of power semiconductors has allowed the increase switching frequencies and the power ratings of these devices, permitting the use of PWM modulation techniques. This paper mainly focuses the DC bus voltage

Jon Andoni Barrena; Luis Marroyo; Miguel Ángel Rodríguez; José Ramón Torrealday

2008-01-01

81

Design of a 1MHz LLC Resonant Converter Based on a DSP-Driven SOI Half-Bridge Power MOS Module  

Microsoft Academic Search

In this paper, the design of a 1-MHz LLC resonant converter prototype is presented. Aiming to provide an integrated solution of the resonant converter, a half-bridge (HB) power metal oxide semiconductor (MOS) module employing silicon-on-insulator technology has been designed. Such a technology, which is suitable for high-voltage and high-frequency applications, allows enabling HB power MOSFET modules operating up to 3MHz

Humphrey de Groot; Eric Janssen; Rosario Pagano; Kees Schetters

2007-01-01

82

Design of a 1 MHz LLC Resonant Converter based on a DSP-driven SOI Half-Bridge Power MOS Module  

Microsoft Academic Search

In this paper, the design of a 1 MHz LLC resonant converter prototype is presented. Aiming to provide an integrated solution of the resonant converter, a half-bridge power MOS module employing silicon-on-insulator (SOI) technology has been designed. Such a technology, which is suitable for high-voltage and high-frequency applications, allows enabling HB power MOSFET modules operating up to 3 MHz with

H. de Groot; E. Janssen; R. Pagano; K. Schetters Philips Semiconductors

2006-01-01

83

A single-stage power factor correction AC\\/DC converter based on zero voltage switching full bridge topology with two series-connected transformers  

Microsoft Academic Search

A single-stage power factor correction ac\\/dc converter based on zero voltage switching (ZVS) full bridge topology with two series-connected transformers is proposed in this paper. The proposed converter offers a very wide ZVS range due to the configuration of two series-connected transformers. It features a high efficiency over wide load ranges. Furthermore, it shows the low voltage stress on a

Tae-Sung Kim; Gwan-Bon Koo; Gun-Woo Moon; Myung-Joong Youn

2006-01-01

84

Novel current mode AC\\/AC converters with high frequency AC link  

Microsoft Academic Search

The research on AC\\/AC converters are mainly limited to the thyristor phase-controlled cycloconverters and matrix converters without electrical isolation. In this paper the voltage mode AC\\/AC converter with high frequency electrical isolation based on forward converter was proposed. A family of the current mode AC\\/AC converters with high frequency electrical isolation based on flyback converters, which can transfer one unregulated

Daolian Chen; Lei Li; Shengyang Lin; Chen Song

2003-01-01

85

Comparisons of two kinds of AC\\/AC converters with high frequency link  

Microsoft Academic Search

Novel AC\\/AC converters with high frequency ac link are composed of two kinds of AC\\/AC converters, which are voltage mode based on Forward converter and current mode based on Flyback converter. The circuit configuration and topology, control strategy, principle characteristics, design criteria of the key circuit parameters, and principle prototype of two-kinds converters are deeply and comparatively investigated firstly in

Lei Li; Qinglong Zhong

2008-01-01

86

Novel Current Mode AC\\/AC Converters with High Frequency AC Link  

Microsoft Academic Search

A novel circuit topologies family of the current mode AC\\/AC converter with high frequency ac link, based on flyback converter, are proposed. These circuit topologies which can transfer one unregulated sinusoidal voltage with high THD into another regulated constant frequency sinusoidal voltage with low THD, are constituted of input cycloconverter, high frequency storage transformer and output cycloconverter. The circuit topologies

Daolian Chen; Lei Li; Jian Liu; Shengyang Lin; Chen Song

2005-01-01

87

Design and Comparison of 4kV Neutral-Point-Clamped, Flying-Capacitor, and Series-Connected H-Bridge Multilevel Converters  

Microsoft Academic Search

This paper describes the design of a (4-kV, 4.16-MVA) three-level neutral-point-clamped-, three-level flying-capacitor-, four-level flying-capacitor-, and nine-level seriesconnected H-bridge voltage-source converter on the basis of state-of-the-art 6.5-, 4.5-, 3.3- and 1.7-kV insulated gate bipolar transistors. The semiconductor loss distribution and the design of semiconductors and passive components are compared for a medium switching frequency assuming a constant converter efficiency of

Seyed Saeed Fazel; Steffen Bernet; Dietmar Krug; Kamran Jalili

2007-01-01

88

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

Microsoft Academic Search

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

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

2002-01-01

89

Energybalance and sliding mode control strategies of a cascade H-bridge multilevel converter for grid-connected PV systems  

Microsoft Academic Search

This work presents the design of a sliding-mode based current controller for a Cascade Full Bridge Multilevel Inverter grid connected PV system. The design also includes a modulation strategy to share the control action among the cascade-connected bridges in order to concurrently synthesize a multilevel waveform and to keep each of the PVG at its maximum operating point. Experimental results

Juan José Negroni; Domingo Biel; Francesc Guinjoan; Carlos Meza

2010-01-01

90

Design of integrated passive component for a 1 MHz 1 kW half-bridge LLC resonant converter  

Microsoft Academic Search

The LLC resonant converter has some special characteristics to make it an excellent candidate for front-end DC\\/DC conversion in a distributed power system. Even with advanced topology, to achieve high power density, the passive component design is still the key issue. Passive integration is used to integrate all the passive components within the resonant tank of the LLC resonant converter

Yan Liang; Wenduo Liu; Bing Lu; J. D. van Wyk

2005-01-01

91

Design Exploration of Aerodynamic Wing Shape for RLV Flyback Booster  

NASA Astrophysics Data System (ADS)

The wing shape of flyback booster for a Two-Stage-To-Orbit reusable launch vehicle has been optimized considering four objectives. The objectives are to minimize the shift of aerodynamic center between supersonic and transonic conditions, transonic pitching moment and transonic drag coefficient, as well as to maximize subsonic lift coefficient. The three-dimensional Reynolds-averaged Navier-Stokes computation using the modified Spalart-Allmaras one-equation model is used in aerodynamic evaluation accounting for possible flow separations. Adaptive range multi-objective genetic algorithm is used for the present study because tradeoff can be obtained using a smaller number of individuals than conventional multi-objective genetic algorithms. Consequently, four-objective optimization has produced 102 non-dominated solutions, which represent tradeoff information among four objective functions. Moreover, Self-Organizing Maps have been used to analyze the present non-dominated solutions and to visualize tradeoffs and influence of design variables to the four objectives. Self-Organizing Maps contoured by the four objective functions and design variables are found to visualize tradeoffs and effects of each design variable.

Chiba, Kazuhisa; Obayashi, Shigeru; Nakahashi, Kazuhiro

92

An On-Line UPS System With Power Factor Correction and Electric Isolation Using BIFRED Converter  

Microsoft Academic Search

This paper presents the design consideration and performance analysis of an on-line, low-cost, high performance, and single-phase uninterruptible power supply (UPS) system based on a boost integrated flyback rectifier\\/energy storage dc\\/dc (BIFRED) converter. The system consists of an isolated ac\\/dc BIFRED converter, a bidirectional dc\\/dc converter, and a dc\\/ac inverter. It provides input power factor correction, electric isolation of the

Adel Nasiri; Zhong Nie; Stoyan B. Bekiarov; Ali Emadi

2008-01-01

93

IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 22, NO. 2, MARCH 2007 461 Current-Fed Dual-Bridge DCDC Converter  

E-print Network

filter capacitance. Detailed analysis shows the proposed converter can have either lower voltage stress advantages of cur- rent-fed topologies include immunity from transformer flux-im- balance and no output

Lehman, Brad

94

Flyback Inverter Controlled by Sensorless Current MPPT for Photovoltaic Power System  

Microsoft Academic Search

This paper presents a flyback inverter controlled by sensorless current maximum power point tracking (MPPT) for a small photovoltaic (PV) power system. Although the proposed system has small output power such as 300 W, a few sets of small PV power systems can be easily connected in parallel to yield higher output power. When a PV power system is constructed

N. Kasa; T. Iida; L. Chen

2005-01-01

95

Design and Comparison of Two Front-end Dc\\/Dc Converters: LLC Resonant Converter and Soft-switched Phase-shifted Full-bridge Converter with Primary-side Energy Storage Inductor  

Microsoft Academic Search

This paper presents detailed design and comparison of two front-end Dc\\/Dc converters which are suitable especially for the medium-power level applications with low output voltage and high output current both. Where, the LLC resonant converter drawn more and more attention recently shows its essential advantages in high conversion efficiency and high power density. However, due to the variable-frequency control strategy,

Chen Zhao; Xinke Wu; Zhaoming Qian

2009-01-01

96

Magnetorheological converters  

SciTech Connect

The authors study the problems of constructing an electrohydraulic converter functioning based on the magnetoheological effect: the magnetorheological throttle (MR throttle). Requirements are listed that must be taken into account in developing the MR throttle. The paper attempts to calculate the flow-rate characteristics of the MR throttle. The rheological equation which describes sufficiently the mechanical properties of the magnetoheological suspensions is presented. The paper examines the calculation of the magnetic inductor for the example of a toroidal core with a gap, which simultaneously functions as the slot throttling channel. The use of the designs described enabled the development of bridge converters, which have a flat amplitude-frequency characteristic in the range 200-250 Hz and which have good energy indicators. Typical experimental logarithmic amplitude-frequency and phase-frequency characteristics of a bridge converter are shown.

Zal'tsgendler, E.A.; Kolomentsev, A.V.; Kordonskii, V.I.; Madorskii, L.S.

1986-04-01

97

A power-equalized harmonic-elimination scheme for utility-connected cascaded H-bridge multilevel converters  

Microsoft Academic Search

Although fundamental frequency switching has been the preferred method for high-power medium-voltage multilevel converters, the technology of current generation power semiconductors has made it possible to use higher rates. In utility-connected applications, where a restricted modulation index range is usually sufficient, a main requirement is for very tight control over individual harmonics. For these reasons, this paper considers the application

Joseph Vassallo; Jon C. Clare; Patrick W. Wheeler

2003-01-01

98

Digital Bridges: Bridges of the Nineteenth Century  

NSDL National Science Digital Library

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

2002-01-01

99

Novel Current-Mode AC\\/AC Converters With High-Frequency AC Link  

Microsoft Academic Search

A novel circuit-topology family of the current-mode AC\\/AC converter with high-frequency AC link, based on a Flyback converter, is proposed. These circuit topologies, which can transfer one unregulated sinusoidal voltage with high total harmonic distortion (THD) into another regulated constant-frequency sinusoidal voltage with low THD, are composed of input cycloconverter, high-frequency storage transformer, and output cycloconverter. The circuit-topology family includes

Daolian Chen

2008-01-01

100

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)

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.

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

101

Parallel Power Flow AC\\/DC Converter with High Input Power Factor and Tight Output Voltage Regulation for Universal Voltage Application  

Microsoft Academic Search

In this paper, a new parallel-connected single phase power factor correction (PFC) topology using flyback converter in parallel with forward converter is proposed to improve the input power factor with simultaneously output voltage regulation taking consideration of current harmonic norms. Paralleling of converter modules is a well-known technique that is often used in medium-power applications to achieve the desired output

A. K. Jha; K. H. Babu; B. M. Karan

2006-01-01

102

Analysis of the zero-current-switched quasiresonant converters used as power factor preregulators  

Microsoft Academic Search

The use of zero-current-switched quasi-resonant converters (ZCS-QRCs) as power factor preregulators (PFPs) is studied. The study is applicable to boost, buck-boost, flyback, SEPIC, and Cuk topologies. The main conclusion is that the switching frequency variation range using a half-wave resonant switch is lower than that using a full-wave resonant switch if the load connected to the output is almost constant.

P. Gil; J. Sebastian; J. A. Cobos; J. Uceda; F. Aldana

1992-01-01

103

Using zero-current-switched quasiresonant converters as power factor preregulator  

Microsoft Academic Search

Th use of zero-current-switched quasiresonant power converters (ZCS-QRCs) as power factor preregulators (PFPs) is studied. The study is applicable to boost, buck-boost, flyback, SEPIC, and Cuk topologies. The main conclusion obtained is that the switching frequency variation range using a half-wave resonant switch is lower than that using a full-wave resonant switch if the load connected to the output is

J. Sebastian; J. Uceda; J. A. Cobos; P. Gil

1991-01-01

104

Power converter  

NASA Technical Reports Server (NTRS)

A dc-to-dc converter employs four transistor switches in a bridge to chop dc power from a source, and a voltage multiplying diode rectifying ladder network to rectify and filter the chopped dc power for delivery to a load. The bridge switches are cross coupled in order for diagonally opposite pairs to turn on and off together using RC networks for the cross coupling to achieve the mode of operation of a free running multivibrator, and the diode rectifying ladder is configured to operate in a push-pull mode driven from opposite sides of the multivibrator outputs of the ridge switches. The four transistor switches provide a square-wave output voltage which as a peak-to-peak amplitude that is twice the input dc voltage, and is thus useful as a dc-to-ac inverter.

Black, J. M. (inventor)

1981-01-01

105

Zero-voltage switching technique in dc/dc converters  

NASA Astrophysics Data System (ADS)

A novel resonant switch operating under the principle of zero-voltage switching is presented. In contrast to the zero-current switching, this technique eliminates the switching loss and dv/dt noise due to the discharging of MOSFET junction capacitances and the reverse recovery of diodes, and enables the converters to operate at high frequencies. A dc analysis of the converter is carried out. The duality relationship between the zero-current switching technique and the zero-voltage switching technique is derived. The two techniques are compared using an example showing the duality between a current-mode quasi-resonant Buck converter and a voltage-mode quasi-resonant boost converter. A 5-MHz 50 V to 5 V flyback converter employing the zero-voltage switching technique has been implemented. The circuit contains the smallest number of components possible, and yet maintains high efficiency at high switching frequency.

Liu, Kwang-Hwa; Lee, Fred C. Y.

1990-07-01

106

Comparison of converter topologies for charging capacitors used in pulsed load applications  

NASA Technical Reports Server (NTRS)

The authors present a qualitative comparison of different power converter topologies which may be utilized for charging capacitors in pulsed power applications requiring voltages greater than 1 kV. The operation of the converters in capacitor charging applications is described, and relevant advantages are presented. All of the converters except one may be classified in the high-frequency switching category. One of the benefits from high-frequency operation is a reduction in size and weight. The other converter discussed is a member of the command resonant changing category. The authors first describe a boost circuit which functions as a command resonant charging circuit and utilizes a single pulse of current to charge the capacitor. The discussion of high-frequency converters begins with the flyback and Ward converters. Then, the series, parallel, and series/parallel resonant converters are examined.

Nelms, R. M.; Schatz, J. E.; Pollard, Barry

1991-01-01

107

Active Harmonic Elimination in Multilevel Converters Using FPGA Control  

E-print Network

for cascaded H-bridges multilevel converter control with unequal DC sources. First, the multilevel converter H- bridge multilevel converter with a real-time controller based on Altera FLEX 10K fieldActive Harmonic Elimination in Multilevel Converters Using FPGA Control Zhong Du, Leon M. Tolbert

Tolbert, Leon M.

108

Harmonic Elimination for Multilevel Converter with Programmed PWM Method  

E-print Network

wave is produced. An experimental 11-level H-bridge multilevel converter with a first- on, first. An experimental 11-level H-bridge multilevel converter with a first-on, first-off switching strategy (usedHarmonic Elimination for Multilevel Converter with Programmed PWM Method Zhong Du, Leon M. Tolbert

Tolbert, Leon M.

109

Bridge permeameter  

DOEpatents

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.

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

1996-01-01

110

Bay Bridge 18 [9] McKeown, Nick  

E-print Network

for the switch would include: Bridge/Router Interface Card Protocol Converter(s) onthe cardwouldin- terfaceBay Bridge 18 [9] McKeown, Nick \\Segmentation and Reassembly for Cell based Mis-ordering Networks" Hewlett-Packard Technical Report HPL-91-176. [10] Taft, Nina \\Bridge Protocols for an SMDS-FDDI Remote

McKeown, Nick

111

Straw Bridges  

NSDL National Science Digital Library

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.

Museum of Science and Industry, Chicago

2012-01-01

112

SINGLE STAGE GRID CONVERTERS FOR BATTERY ENERGY STORAGE  

E-print Network

are switched. The first two topologies were introduced by Baker in 1975 the Cascaded H-Bridge (CHB) converter@iet.aau.dk Keywords: BESS, multilevel converters, medium voltage. Abstract Integration of renewable energy systems, the multilevel converters are the key technology. Multilevel converters represent a smart way to connect power

Munk-Nielsen, Stig

113

Analysis and Design of LLC Resonant Converter with Integrated Transformer  

Microsoft Academic Search

LLC resonant converter has a lot of advantages over the conventional series resonant converter and parallel resonant converter; narrow frequency variation over wide load and input variation, Zero Voltage Switching (ZVS) for entire load range and integration of magnetic components. This paper presents analysis and design consideration for half-bridge LLC resonant converter with integrated transformer. Using the fundamental approximation, the

Hangseok Choi

2007-01-01

114

Integrated multilevel converter and battery management  

Microsoft Academic Search

A cascaded H-bridge multilevel converter is proposed as a BLDC drive incorporating real-time battery management. Intelligent H-bridges are used to monitor battery cells whilst simultaneously increasing their performance by reducing the variation between cells and controlling their discharge profiles.

K. Wilkie; D. Stone; C. Bingham; M. Foster

2008-01-01

115

Discussion on Modulation Methods for Flyback-type Single-Phase Inverters with Enhanced Power Decoupling for Photovoltaic AC Module Systems  

NASA Astrophysics Data System (ADS)

A photovoltaic AC module system has been expected to be installed on the private residences. The AC module inverter needs an active power decoupling circuit in order to enlarge the lifetimes of the inverter by eliminating a large electrolytic capacitor on the DC input bus. This paper proposes a novel modulation method, which we call Time-shared Magnetizing Modulation (TMM) method, realizing the power decoupling in the AC module flyback inverter as well as improving the efficiency conversion. The Sequential Magnetizing Modulation (SMM) method, which the authors have proposed earlier, are compared with the proposed method in operation principle and conversion efficiency point of view. It is verified that the TMM method has advantage with respect to the conversion efficiency. This paper concludes that the flyback inverter with the TMM method for the power decoupling is one of the suitable method for a single-phase grid interactive inverter used in the AC module system.

Hirao, Takashi; Shimizu, Toshihisa; Ishikawa, Mutsuo; Yasui, Kiyoto

116

Popsicle Bridge  

NSDL National Science Digital Library

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.

Ieee

2013-08-30

117

Spaghetti Bridge  

NSDL National Science Digital Library

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.

K-12 Outreach Office,

118

Bridge permeameter  

DOEpatents

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.

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

1996-08-13

119

Spaghetti Bridge  

NSDL National Science Digital Library

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.

Cosi

2009-01-01

120

Designing Bridges  

NSDL National Science Digital Library

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.

Integrated Teaching And Learning Program And Laboratory

121

Soft switching active snubbers for DC/DC converters  

SciTech Connect

A soft-switching active snubber is proposed to reduce the turn-off losses of the insulated gate bipolar transistor (IGBT) in a buck converter. The soft-switching snubber provides zero-voltage switching for the IGBT, thereby reducing its high turn-off losses due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates at zero-voltage and zero-current switching. The size of the auxiliary switch compared to the main switch makes this snubber a good alternative to the conventional snubber or even to passive low-loss snubbers. The use of the soft-switching active snubber permits the IGBT to operate at high frequencies with an improved RBSOA. In the experimental results reported for a 1 kW, 40 kHz prototype, combined switching/snubbing losses are reduced by 36% through the use of the active snubber compared to a conventional RCD snubber. The use of an active snubber capacitor during turn-off. The generic snubber cell for the buck converter is generalized to support the common nonisolated dc/dc converters (buck, boost, buck-boost, Cuk, sepic, zeta) as well as isolated dc/dc converters (forward, flyback, Cuk, and sepic).

Elasser, A.; Torrey, D.A. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Electric Power Engineering] [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Electric Power Engineering

1996-09-01

122

Generation of Triggering Signals for Multilevel Converter  

Microsoft Academic Search

Multilevel converter has become attractive in the power industries and it can be applied in many applications especially on improvement of the power quality. This paper presents the generation of triggering signals used to control the cascaded H-bridge (CHB) multilevel converter. One of the carrier based pulse width modulation scheme which is level shifted multicarrier modulation has been chosen to

S. A. Bashi; N. F. Mailah; M. Z. Kadir; K. H. Leong

123

Elimination of Harmonics in a Multilevel Converter for HEV Applications  

E-print Network

- tions are found. II. Cascaded H-bridges The cascade multilevel inverter consists of a series of H-phase structure of a multilevel cascaded H-bridges inverter. to a single-phase full-bridge inverter. Each inverter1 Elimination of Harmonics in a Multilevel Converter for HEV Applications Leon M. Tolbert1,2 , John

Tolbert, Leon M.

124

Thermionic converter  

DOEpatents

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.

Fitzpatrick, G.O.

1987-05-19

125

A New Approach to Solving the Harmonic Elimination Equations for a Multilevel Converter  

E-print Network

. Cascaded H-bridges A cascade multilevel inverter consists of a series of H- bridge (single-phase full-bridgeA New Approach to Solving the Harmonic Elimination Equations for a Multilevel Converter John N is presented to compute the switch- ing angles in a multilevel converter so as to produce the required

Tolbert, Leon M.

126

Spaghetti Bridge  

NSDL National Science Digital Library

Learners explore the field of civil engineering by making a bridge using spaghetti as their primary building material. Then they test their bridges to see how much weight they can carry before breaking. This activity allows learners to engage in the entire engineering process as they design, build, test, then discuss their bridges. Resource includes investigating questions to extend learning. Time estimated for activity can be split across multiple meetings.

Institute, Worcester P.

2013-01-01

127

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

NASA Astrophysics Data System (ADS)

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%.

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

2014-08-01

128

Straw Bridges  

NSDL National Science Digital Library

Working as engineering teams, students design and create model beam bridges using plastic drinking straws and tape as their construction materials. Their goal is to build the strongest bridge with a truss pattern of their own design, while meeting the design criteria and constraints. They experiment with different geometric shapes and determine how shapes affect the strength of materials. Let the competition begin!

Integrated Teaching And Learning Program

129

Thermionic converter  

DOEpatents

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.

Fitzpatrick, Gary O. (Livermore, CA)

1987-05-19

130

New transfer function model for PWM power converter  

Microsoft Academic Search

An equivalent circuit for a power converter bridge leg is derived. In this circuit model the PWM (pulsewidth modulation) power switches are represented by dependent power sources. By this approach PWM switching converters can be represented by a continuous, but nonlinear, electric circuit. By making reasonable assumptions, a linear transfer function model for the power converter is developed. The root

Guijun Yao; Lars Norum

1990-01-01

131

Reduced Switching Frequency Computed PWM Method for Multilevel Converter Control  

E-print Network

. An experimental 11-level H-bridge multilevel converter with a first-on first-off switching strategy (usedReduced Switching Frequency Computed PWM Method for Multilevel Converter Control Zhong Du, Leon M computed PWM methods for 11-level multilevel converters to eliminate the specified harmonics in the output

Tolbert, Leon M.

132

Transient of modified HVDC converters  

Microsoft Academic Search

The bridge circuit used in high voltage direct current (HVDC) converters may be modified by including by-pass thyristor valves connected to tapping points on the secondary windings of the transformer to give a reduction in both harmonic generation and reactive volt–ampere absorption for the rectifier and inverter modes of operation.In this paper, control strategies for the transient response of the

Hussein. D. Al-Majali; Sulaiman. M. Al-Dhalaan

2007-01-01

133

Bridging Anticoagulation  

MedlinePLUS

... practical approach . Blood . 2011 ; 117 : 5044 – 5049 . FREE Full Text Spyropoulos AC . Bridging therapy and oral anticoagulation: current ... doi: 10.1161/CIRCULATIONAHA.111.084517 Extract Free » Full Text Free PDF Free Classifications Cardiology Patient Page Services ...

134

Spaghetti Bridge  

NSDL National Science Digital Library

Play with your food while learning about engineering! Build a spaghetti bridge, then test its strength by piling on the marshmallows, raw spaghetti, raw linguine and coins. Investigate the difference between the strength of bridges made from flat and round building materials (spaghetti is round, while linguine is flat). Learn by doing that circles are among the strongest shapes in nature, and that external and internal stress distributes itself evenly throughout a round structure.

Sciencenter

1999-01-01

135

Cascaded H-bridge Multilevel Inverters -A Reexamination  

Microsoft Academic Search

Multilevel converters have gained popularity in high-power applications due to their low switch voltage stress and modularity. Cascaded H-bridge converters are a promising breed of multilevel converters which generally require several independent dc sources. Recently, existence of a redundant switching state has been utilized to replace the independent voltage sources with capacitors except for the one with the highest voltage

Jingsheng Liao; Kai Wan; M. Ferdowsi

2007-01-01

136

Linking Bridges  

NSDL National Science Digital Library

This blog post presents three puzzles which provide an opportunity for learners to use the strategy of trial and error and logical reasoning. The challenge is to connect all of the islands with bridges so that the number on the island corresponds to the number of bridges going to it or from it. This activity also provides the opportunity for students to be puzzle designers by including a blank grid page on which students can design their own versions of the puzzle to share with classmates.

Young, David

2014-01-28

137

Low Switching Frequency Active Harmonic Elimination in Multilevel Converters with Unequal DC Voltages  

E-print Network

method for the cascaded H-bridges multilevel converter when supplied by unequal DC sources. FirstLow Switching Frequency Active Harmonic Elimination in Multilevel Converters with Unequal DC, the multilevel converter is decoupled into individual unipolar converters, and the low order harmonics (such

Tolbert, Leon M.

138

Bridges, 1999.  

ERIC Educational Resources Information Center

This volume contains articles about writing, best practice, portfolio assessment, and technology, as well as original poetry and book reviews. Articles in the volume are: "Teaching Writing: Making Connections" (Eric Schott); "Empowering Teachers: A Success Story" (Sandra L. Krivak); "Bridging the Gap between the Classroom and Employment" (Linda C.…

Wilcox, Bonita; Manear, John; Slifkin, Josh M.

139

Elimination of Harmonics in a Multilevel Converter using the Theory of Symmetric  

E-print Network

multilevel inverter consists of a series of H- bridge (single-phase full-bridge) inverter units. The genElimination of Harmonics in a Multilevel Converter using the Theory of Symmetric Polynomials to compute the switch- ing angles in a multilevel converter so as to produce the required fundamental voltage

Tolbert, Leon M.

140

Control of Cascaded Multilevel Converters with Unequal Voltage Sources for HEVs  

E-print Network

The cascade multilevel inverter consists of a series of H- bridge (single-phase full-bridge) inverter unitsControl of Cascaded Multilevel Converters with Unequal Voltage Sources for HEVs Leon M. Tolbert1 2 possible solu- tions are found. Keywords­ Hybrid Electric Vehicles, Multilevel Convert- ers, Harmonic

Tolbert, Leon M.

141

Bridge Building  

NSDL National Science Digital Library

This is a quick activity (on page 2 of the PDF) about how the arrangement of carbon atoms determines carbon's different properties. Learners will build bridges with Post-It notes that model two types of carbon molecules, graphite and carbon nanotubes, and test which structure of the same material can bear the weight of the most pennies. Also relates to linked video, DragonflyTV Nano: Hockey Sticks.

Twin Cities Public Television, Inc.

2008-01-01

142

Building Bridges  

NSDL National Science Digital Library

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.

Roger Day

2000-01-01

143

Novel Cell based on Reduced Single-phase Active Front End for Multicell Converters.  

E-print Network

for cascaded multilevel inverters. The cell uses a reduced single- phase active rectifier at the input and an H-bridge the continuous development of Multilevel converters due to their capability of handling voltages up to 6.9[k based on a half-bridge PWM rectifier and a three-level sin- gle phase inverter (H-bridge). A standard

Duffy, Ken

144

Fault Tolerant Reconfiguration System for Asymmetric Multilevel Converters Using BiDirectional Power Switches  

Microsoft Academic Search

Asymmetric multilevel converters can optimise the number of levels by using H bridges scaled in power of three. The shortcoming of this topology is that the H bridges are not interchangeable and then, under certain faulty conditions, the converter cannot operate. A reconfiguration system based on bi-directional electronic valves has been designed for a 3-phase cascaded H-bridges. Once a fault

J. Dixon; P. Barriuso; M. Ortuzar; L. Moran; J. Pontt; J. Rodriguez

2007-01-01

145

Fault-Tolerant Reconfiguration System for Asymmetric Multilevel Converters Using Bidirectional Power Switches  

Microsoft Academic Search

Asymmetric multilevel converters can optimize the number of levels by using H-bridges scaled in the power of three. The shortcoming of this topology is that the H-bridges are not interchangeable, and then, under certain faulty conditions, the converter cannot operate. A reconfiguration system based on bidirectional electronic valves has been designed for three-phase cascaded H-bridge inverters. Once a fault is

Pablo Barriuso; Juan Dixon; Patricio Flores; Luis Moran

2009-01-01

146

Active harmonic elimination in multilevel converters using FPGA control  

Microsoft Academic Search

This paper presents an optimal total harmonic distortion (THD) control algorithm referred to as active harmonic elimination method for cascaded H-bridges multilevel converter control with unequal DC sources. First, the multilevel converter is decoupled into unipolar converters, the low order harmonics, such as the 5th, 7th, 11th and 13th are eliminated by using elimination theory, and the minimum THD combination

Zhong Du; Leon M. Tolbert; John N. Chiasson

2004-01-01

147

Buck and boost derived converter for livestock\\/poultry stunning applications  

Microsoft Academic Search

This paper proposes a buck and boost derived converter associated with a full-bridge inverter for livestock\\/poultry stunning applications. The derived converter is formed by combining buck and boost converters to step up or step down input voltage. Compared with the conventional buck-boost converter, the proposed converter can raise efficiency of 4-6% under full load condition. In the paper, mechanism of

T.-F. Wu; S.-Y. Tseng; J.-S. Hu; Y.-M. Chen

2006-01-01

148

A minimized switch count single-phase AC\\/AC converter with active front end  

Microsoft Academic Search

A three-switch single-phase converter is introduced in this paper which is a counterpart to back-to-back half-bridge converters. Introducing the new converter and elaborating its modulation scheme, a single-phase ac\\/ac converter is proposed based on it. The proposed topology enjoys the benefits of an ideal single-phase ac\\/ac converter such as low THD input current, unity power factor, fast dynamic response and

A. Fatemi; M. Azizi; M. Mohamadian; F. Ashrafzadeh

2012-01-01

149

11-level Cascaded H-bridge Grid-tied Inverter Interface with Solar Panels  

E-print Network

the methodology for grid connection of renewable resources. Keywords ­ multilevel converter, cascaded H-bridges or in parallel to provide the desired voltage level to the inverter. The cascaded H-bridge multilevel inverter focuses on the single-phase 11-level (5 H- bridges) cascade multilevel inverter. II. MULTILEVEL INVERTER

Tolbert, Leon M.

150

Modulation Extension Control for Multilevel Converters Using Triplen Harmonic Injection with Low Switching Frequency  

E-print Network

was implemented with an 11-level H-bridge multilevel converter and an 8µs control resolution to demonstrateModulation Extension Control for Multilevel Converters Using Triplen Harmonic Injection with Low@utk.edu Abstract--This paper presents a modulation extension control method for multilevel converters with low

Tolbert, Leon M.

151

Chapter 31 Multilevel Power Converters Surin Khomfoi and Leon M. Tolbert  

E-print Network

in the literature: cascaded H-bridges converter with separate dc sources, diode clamped (neutral- clampedChapter 31 Multilevel Power Converters Surin Khomfoi and Leon M. Tolbert The University switch directly. As a result, a multilevel power converter structure has been introduced

Tolbert, Leon M.

152

Theory of operation, design procedure and simulation of a bidirectional LLC resonant converter for vehicular applications  

Microsoft Academic Search

Usually a LLC resonant converter is used in applications with high input voltage (300-400 V) and low output voltage (48-60 V). This type of converter includes a half bridge topology and is only designed for unidirectional power transfer. Since the benefits of a LLC resonant converter are high efficiency, high power density and low EMI, it is a very interesting

Georg Pledl; Matthias Tauer; Dominik Buecherl

2010-01-01

153

Simulation of AC-DC step up and step down converter  

Microsoft Academic Search

Various applications in the modern world require DC supply. Some applications needs low DC voltage and some require considerably high DCvoltage. We get AC supply and that needs to be converted to DC for these applications. In this paper AC - DC step up and step down converters without the use of bridge rectification is dealt. In step up converter,

B. Partheeban; Brintha Jane Justin

2011-01-01

154

Parallel input parallel output high voltage bi-directional converters for driving dielectric electro active polymer actuators  

NASA Astrophysics Data System (ADS)

Dielectric electroactive polymer (DEAP) actuators are capacitive devices which provide mechanical motions when charged electrically. The charging characteristics of a DEAP actuator depends on its size, voltage applied to its electrodes, and its operating frequency. The main idea of this paper is to design and implement driving circuits for the DEAP actuators for their use in various applications. This paper presents implementation of parallel input, parallel output, high voltage (~2.5 kV) bi-directional DC-DC converters for driving the DEAP actuators. The topology is a bidirectional flyback DC-DC converter incorporating commercially available high voltage MOSFETs (4 kV) and high voltage diodes (5 kV). Although the average current of the aforementioned devices is limited to 300 mA and 150 mA, respectively, connecting the outputs of multiple converters in parallel can provide a scalable design. This enables operating the DEAP actuators in various static and dynamic applications e.g. positioning, vibration generation or damping, and pumps. The proposed idea is experimentally verified by connecting three high voltage converters in parallel to operate a single DEAP actuator. The experimental results with both film capacitive load and the DEAP actuator are shown for a maximum charging voltage of 2 kV.

Thummala, P.; Zhang, Z.; Andersen, M. A. E.; Rahimullah, S.

2014-03-01

155

Feasibility study for convertible engine torque converter  

NASA Technical Reports Server (NTRS)

The feasibility study has shown that a dump/fill type torque converter has excellent potential for the convertible fan/shaft engine. The torque converter space requirement permits internal housing within the normal flow path of a turbofan engine at acceptable engine weight. The unit permits operating the engine in the turboshaft mode by decoupling the fan. To convert to turbofan mode, the torque converter overdrive capability bring the fan speed up to the power turbine speed to permit engagement of a mechanical lockup device when the shaft speed are synchronized. The conversion to turbofan mode can be made without drop of power turbine speed in less than 10 sec. Total thrust delivered to the aircraft by the proprotor, fan, and engine during tansient can be controlled to prevent loss of air speed or altitude. Heat rejection to the oil is low, and additional oil cooling capacity is not required. The turbofan engine aerodynamic design is basically uncompromised by convertibility and allows proper fan design for quiet and efficient cruise operation. Although the results of the feasibility study are exceedingly encouraging, it must be noted that they are based on extrapolation of limited existing data on torque converters. A component test program with three trial torque converter designs and concurrent computer modeling for fluid flow, stress, and dynamics, updated with test results from each unit, is recommended.

1985-01-01

156

Bridging the Gaps  

NSDL National Science Digital Library

Students are presented with a brief history of bridges as they learn about the three main bridge types: beam, arch and suspension. They are introduced to two natural forces — tension and compression — common to all bridges and structures. Throughout history, and today, bridges are important for connecting people to resources, places and other people. Students become more aware of the variety and value of bridges around us in our everyday lives.

2014-09-18

157

Mathematics and Computers in Simulation 63 (2003) 197208 Real-time computer control of a multilevel converter  

E-print Network

. The present work addresses both of these issues. 2. Cascaded H-bridges Cascade multilevel inverter consists of a series of H-bridge (single-phase full-bridge) inverter units. The general function of this multilevel of a multilevel converter using the mathematical theory of resultants John Chiasson, Leon Tolbert, Keith Mc

Tolbert, Leon M.

158

The Use of Power Sums to Solve the Harmonic Elimination Equations for Multilevel Converters EPE Journal Vol. 15 no  

E-print Network

A cascade multilevel inverter consists of a series of H-bridge (sin- gle-phase full-bridge) inverter unitsThe Use of Power Sums to Solve the Harmonic Elimination Equations for Multilevel Converters EPE an 11-level inverter. A preliminary version of this work was presented in [17]. Cascaded H-bridges

Tolbert, Leon M.

159

The unipolarity phase-shifted controlled voltage mode AC\\/AC converters with high frequency AC link  

Microsoft Academic Search

The uni-polarity phase-shifted controlled voltage mode AC\\/AC converters with high frequency ac link are firstly proposed and deeply investigated. The converters are constituted of input cycloconverter, high frequency transformer, output cycloconverter, input and output filters. It includes full bridge-full wave mode and full bridge-full bridge mode topologies. By using phase shifting control, the leakage inductance energy and the output filtering

Lei Li; Daolian Chen; Haitao Zhang; Hailang Pan

2003-01-01

160

A Fault-Tolerant Control Strategy for Cascaded H-Bridge Multilevel Rectifiers  

Microsoft Academic Search

Reliability is an important issue in cascaded H-bridge converters (CHB converters) because they use a high number of power semiconductors. A faulty power cell in a CHB converter can potentially lead to expensive downtime and great losses on the consumer side. With a fault-tolerant control strategy, operation can continue with the undamaged cells; thus increasing the reliability of the system.

Hossein Iman-Eini; Shahrokh Farhangi; Jean-Luc Schanen; Mahboubeh Khakbazan-Fard

2010-01-01

161

Harmonic Modelling of Thyristor Bridges using a Simplified Time Domain Method  

E-print Network

of a 6-pulse thyristor bridge connected to an ac network. Balanced firing of the converter and a balanced interface transformer inductance are assumed. For the special case when the ac network is linear, a closed of a nonlinear ac network, a modular converter model is developed that relies on iterative methods. The converter

Lehn, Peter W.

162

Design and implementation of power converters for wind energy conversion system  

Microsoft Academic Search

This paper presents the design and implementation of power converters for wind conversion systems. The power converter can not only transfer the power from a wind generator, but also improve the stability and safety of the system. The proposed system consists of a permanent magnet synchronous generator (PMSG), a DC\\/DC boost converter, a bi-directional DC\\/DC converter and a full-bridge DC\\/AC

A. Chih-Chiang Hua; B. Chien-Hung Cheng

2010-01-01

163

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

Microsoft Academic Search

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,

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

1989-01-01

164

Interleaving Forward Converters with Single-Capacitor Turn-off Snubber for stunning Poultry Applications  

Microsoft Academic Search

This paper proposes an interleaving forward converters with single-capacitor turn-off snubber associated with a full-bridge inverter for poultry stunning applications. The proposed converters can use the single-capacitor snubber to smooth out switch turn-off transient for reducing turn-off loss. As compared with the counterparts of the conventional converter topologies, the proposed converters have the merits of less component counts, higher efficiency

S.-Y. Tseng; J. G. Huang; H.-T. WenandH; H.-H. Chang

2006-01-01

165

Measurement: Converting Distances  

NSDL National Science Digital Library

This lesson helps students understand and practice converting measurements in both English and metric systems. The 8-page pdf begins with a brief introduction to measuring length, English measurement systems, and metric measurement. Students then learn to convert measurements within each system. At the end of the lesson, there are 18 review problems for students to convert measurements on their own. Answers are provided.

2006-01-01

166

Bridging consent: from toll bridges to lift bridges?  

PubMed Central

Background The ability to share human biological samples, associated data and results across disease-specific and population-based human research biobanks is becoming increasingly important for research into disease development and translation. Although informed consent often does not anticipate such cross-domain sharing, it is important to examine its plausibility. The purpose of this study was to explore the feasibility of bridging consent between disease-specific and population-based research. Comparative analyses of 1) current ethical and legal frameworks governing consent and 2) informed consent models found in disease-specific and population-based research were conducted. Discussion Ethical and legal frameworks governing consent dissuade cross-domain data sharing. Paradoxically, analysis of consent models for disease-specific and population-based research reveals such a high degree of similarity that bridging consent could be possible if additional information regarding bridging was incorporated into consent forms. We submit that bridging of consent could be supported if current trends endorsing a new interpretation of consent are adopted. To illustrate this we sketch potential bridging consent scenarios. Summary A bridging consent, respectful of the spirit of initial consent, is feasible and would require only small changes to the content of consents currently being used. Under a bridging consent approach, the initial data and samples collection can serve an identified research project as well as contribute to the creation of a resource for a range of other projects. PMID:21970509

2011-01-01

167

Rotorcraft convertible engine study  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

168

High-Power Converters and AC Drives IEEE PESC2005 Tutorial  

E-print Network

@ee.ryerson.ca http://www.ee.ryerson.ca/~bwu/ 2 High-Power Converters and AC Drives 1. Introduction 2. Cascaded H-Bridge · Multilevel Voltage Source Inverters N dC Cascaded H-bridge (CHB) Inverter dC Two Level Inverter dC Flying1 High-Power Converters and AC Drives IEEE PESC2005 Tutorial Bin Wu PhD, PEng Professor Ryerson

Wu, Bin

169

Surfacing of concrete bridges  

Microsoft Academic Search

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

Vibeke Wegan

170

This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Abstract--Asymmetric multilevel converters can optimize the  

E-print Network

converters can optimize the number of levels by using H bridges scaled in power of three. The shortcoming of this topology is that the H bridges are not interchangeable and then, under certain faulty conditions designed for 3-phase cascaded H-bridge inverters. Once a fault is detected in any of the IGBTs of any H-bridge

Catholic University of Chile (Universidad Católica de Chile)

171

Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's  

NASA Technical Reports Server (NTRS)

In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.

Gruber, Robert P.; Gott, Robert W.

1991-01-01

172

Ac-dc converter firing error detection  

SciTech Connect

Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal.

Gould, O.L.

1996-07-15

173

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.

174

1.2 MW dc-dc converter  

NASA Astrophysics Data System (ADS)

A dc-dc converter has been developed to charge capacitors to 16 kV from a 400 V battery bank. It is designed to charge an 8.5 MJ bank nine times in 3 min. The converter is comprised of six modules, each producing 12.5 A of charging current, and an enclosure which houses the modules and provides control power and a master controller. The six 200 kW modules have a combined power rating of 1.2 MW. The pulse width modulation converter system operates at 24 kHz and contains inverters with power MOSFETs as the principal inverter components, 200 kW transformers and inductors, and full bridge rectifiers with fast recovery diodes. The converter modules have a volume power density of 1.0 MW/cu m and a mass power density of 1.2 kW/kg. The converter design and test results are described.

Homeyer, W. G.; Callanan, R. J.; Bowles, E. E.; Nerem, A.

1993-01-01

175

Control of matrix converters for AC power supplies using genetic algorithms  

Microsoft Academic Search

This paper describes the design philosophy, simulation and testing of AC power supplies using matrix converters. Instead of the classical design using a diode bridge rectifier, a DC link and a PWM inverter, a 3-phase to 3-phase direct AC-AC (matrix) converter has been used as the power conditioning core of the system. An optimizing control design method, using a genetic

Pericle Zanchetta; M. Sumner; J. C. Clare; P. W. Wheeler

2004-01-01

176

Harmonic Elimination in Multilevel Converters John Chiasson, Leon Tolbert, Keith McKenzie and Zhong Du  

E-print Network

], the approach here produces all possible solutions. II. Cascaded H-bridges The cascade multilevel inverter1 Harmonic Elimination in Multilevel Converters John Chiasson, Leon Tolbert, Keith Mc in a multilevel converter so as to produce the re- quired fundamental voltage while at the same time not gen

Tolbert, Leon M.

177

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

178

Control of a single phase H-Bridge multilevel inverter for grid-connected PV applications  

Microsoft Academic Search

This paper proposes a control scheme for a single phase H-bridge multilevel converter for photovoltaic applications. This control approach permits each H-bridge module supply different power levels, allowing an independent maximum power point tracking of each photovoltaic (PV) panel. Since no intermediate stages such boost DC-DC converters are needed, a high efficient solution is obtained compared to the standard PV

E. Villanueva; P. Correa; J. Rodriguez

2008-01-01

179

Bridging spinal cord injuries  

E-print Network

Minireview Bridging spinal cord injuries James W Fawcett Address: Cambridge University Centre for Brain Repair, Robinson Way, Cambridge CB2 0PY, UK. Email: jf108@cam.ac.uk Repair of the injured spinal cord has been one of the great quests... why not transplant Abstract One strategy for spinal cord injury repair is to make cellular bridges that support axon regeneration. However, the bridging cells often fail to integrate with host tissue and may lead to increased pain sensitivity. Recent...

2008-10-15

180

Semiconductor bridge (SCB) detonator  

DOEpatents

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.

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

1999-01-19

181

Performance testing of a high frequency link converter for space station power distribution system  

Microsoft Academic Search

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

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

1989-01-01

182

Low switching frequency active harmonic elimination in multilevel converters with unequal DC voltages  

Microsoft Academic Search

This paper presents an active harmonic elimination modulation control method for the cascaded H-bridges multilevel converter when supplied by unequal DC sources. First, the multilevel converter is decoupled into individual unipolar converters, and the low order harmonics (such as the 5th, 7th, 11th, and 13th) are eliminated by using resultant theory while at the same time the minimum specified harmonic

Zhong Du; Leon M. Tolbert; John N. Chiasson; Hui Li

2005-01-01

183

A novel multicell DC-AC converter for applications in renewable energy systems  

Microsoft Academic Search

This paper presents a novel DC-AC converter for applications in the area of distributed energy generation systems, e.g., solar power systems, fuel-cell power systems in combination with supercapacitor or battery energy storage. The proposed converter is realized using an isolated multicell topology where the total AC output of the system is formed by series connection of several full-bridge converter stages.

Hans Ertl; Johann W. Kolar; Franz C. Zach

2002-01-01

184

10. DETAIL VIEW OF BRIDGE DATEPLATE WHICH READS 'WISCONSIN BRIDGE ...  

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

10. DETAIL VIEW OF BRIDGE DATEPLATE WHICH READS 'WISCONSIN BRIDGE & IRON COMPANY, MILWAUKEE, WIS., 1933' - St. Francis River Bridge, Spanning St. Francis River at U.S. Highway 70, Forrest City, St. Francis County, AR

185

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

186

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

187

2. View of Clark Fork Vehicle Bridge facing northeast. Bridge ...  

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

2. View of Clark Fork Vehicle Bridge facing northeast. Bridge from south shore of Clark Fork River showing 4 1/2 spans. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

188

4. View of Clark Fork Vehicle Bridge facing northeast. Bridge ...  

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

4. View of Clark Fork Vehicle Bridge facing northeast. Bridge from south shoreof Clark Fork River showing 4 spans. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

189

7. View of Clark Fork Vehicle Bridge facing northwest. Bridge ...  

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

7. View of Clark Fork Vehicle Bridge facing northwest. Bridge from south shore of Clark Fork River showing 4 1/2 spans. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

190

3. View of Clark Fork Vehicle Bridge facing southwest. Bridge ...  

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

3. View of Clark Fork Vehicle Bridge facing southwest. Bridge from north shore of Clark Fork River. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

191

PDF to HTML Converter  

NSDL National Science Digital Library

If you're looking for a way to convert pdf files to html, this helpful application can do just that. Visitors just need to click the browse button here to locate the pdf that they wish to transfer. After doing this, they will supply their own email, and seconds later, they will have the converted file. This version is compatible with all operating systems.

2010-01-01

192

Sulphite Railroad Bridge1896, Title Sheet Sulphite Railroad Bridge, Former ...  

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

Sulphite Railroad Bridge-1896, Title Sheet - Sulphite Railroad Bridge, Former Boston & Maine Railroad (originally Tilton & Franklin Railroad) spanning Winnipesautee River, Franklin, Merrimack County, NH

193

Precision bolometer bridge  

NASA Technical Reports Server (NTRS)

Prototype precision bolometer calibration bridge is manually balanced device for indicating dc bias and balance with either dc or ac power. An external galvanometer is used with the bridge for null indication, and the circuitry monitors voltage and current simultaneously without adapters in testing 100 and 200 ohm thin film bolometers.

White, D. R.

1968-01-01

194

Bridge Program Planning Guide  

NSDL National Science Digital Library

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.

Jenkins, Davis

195

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...

196

Virtual Bridge Design Challenge  

ERIC Educational Resources Information Center

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…

Mitts, Charles R.

2013-01-01

197

STEM Bridge Scholarship Program  

E-print Network

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

Buehrer, R. Michael

198

MSPWM & MTPWM techniques for asymmetric H-bridge multilevel inverter  

Microsoft Academic Search

Multilevel inverter is a new breed of power converter which is suited for high power applications. The various topologies of multilevel inverter are diode - clamped, capacitor clamped and cascaded H-bridge inverter. It is an effective solution for increasing the number of levels in output waveform with reduced dc sources and switching elements, thereby dramatically reduces harmonics without increasing the

P. Jamuna; C. Christober Asir Rajan

2012-01-01

199

Multilevel converters-a new breed of power converters  

Microsoft Academic Search

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

Jih-Sheng Lai; Fang Zheng Peng

1996-01-01

200

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.

2009-06-08

201

Vector generator scan converter  

DOEpatents

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O (input/output) channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardward for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold.

Moore, James M. (Livermore, CA); Leighton, James F. (Livermore, CA)

1990-01-01

202

Vector generator scan converter  

DOEpatents

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

Moore, J.M.; Leighton, J.F.

1988-02-05

203

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

204

VIEW OF BRIDGE, LOOKING SOUTHWEST, WITH SOUTHERN PACIFIC RAILROAD BRIDGE ...  

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

VIEW OF BRIDGE, LOOKING SOUTHWEST, WITH SOUTHERN PACIFIC RAILROAD BRIDGE IN BACKGROUND. THE PAVEMENT OF THE NORTH APPROACH IS SEEN BURIED ON THE RIGHT. ROADWAY (CENTER) CROSSES THE USUALLY DRY CHANNEL OF THE SALT RIVER. A BALUSTRADE OF THE MILL AVENUE BRIDGE IS SEEN AT THE LOWER LEFT CORNER - Ash Avenue Bridge, Spanning Salt River at Foot of Ash Avenue, Tempe, Maricopa County, AZ

205

Nonuniversality of entanglement convertibility  

NASA Astrophysics Data System (ADS)

Recently, it has been suggested that operational properties connected to quantum computation can be alternative indicators of quantum phase transitions. In this work we systematically study these operational properties in one-dimensional systems that present phase transitions of different orders. For this purpose, we evaluate the local convertibility between bipartite ground states. Our results suggest that the operational properties, related to nonanalyticities of the entanglement spectrum, are good detectors of explicit symmetries of the model, but not necessarily of phase transitions. We also show that thermodynamically equivalent phases, such as Luttinger liquids, may display different convertibility properties depending on the underlying microscopic model.

Bragança, Helena; Mascarenhas, Eduardo; Luiz, G. I.; Duarte, C.; Pereira, R. G.; Santos, M. F.; Aguiar, M. C. O.

2014-06-01

206

IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 24, NO. 1, MARCH 2009 203 Novel Half-Bridge Inductive DCDC Isolated  

E-print Network

`evre, and Jean-Paul Ferrieux Abstract--This paper proposes a new class of converters based on the inductive input is composed of a dc­dc converter followed by a dc­ac inverter (Fig. 1). This paper will discuss new dc­dc converters based on the half-bridge inductive converter dedi- cated to this interface. First, the basic

Boyer, Edmond

207

Inherent overload protection for the series resonant converter  

NASA Technical Reports Server (NTRS)

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).

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

1983-01-01

208

Bridge : an unraveled architecture  

E-print Network

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 ...

ElHusseiny, Ahmed

2006-01-01

209

The Königsberg Bridge Problem  

NSDL National Science Digital Library

This article, written for middle grades students, relates the history of the famous Konigsberg Bridge problem and introduces the idea of networks and paths that do not retrace themselves. The article concludes with a path the student must work out.

2011-01-01

210

Design Squad: Suspension Bridge  

NSDL National Science Digital Library

In this video segment adapted from Design Squad—a PBS TV series featuring high school contestants tackling engineering challenges—students employ the concepts of tension and compression to build a suspension bridge without the aid of power tools.

WGBH Educational Foundation

2007-08-09

211

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.

212

Onyx Bridg e Volcanology  

E-print Network

Carso n Oregon Onyx Bridg e Cascad e Willamette University etuhcseDs BEECH Boyn itseuHs Volcanology (Turns into Franklin Blvd) 6. Continue on Franklin Blvd until you reach Onyx. 7. Turn right into the Onyx

213

Fractional Watt AMTEC Converter  

NASA Astrophysics Data System (ADS)

We report here the long term performance of a small, multi-tube AMTEC converter. This converter was designed to operate and produce approximately 12 watt of electrical output from a small, 4 to 6 watt radioisotope heat source for remote power applications. It was built and put on test in 1999 using electrical heaters as stand-ins for the radioisotope capsule. Since that time it has accumulated more than 5 years of run time at an input heater temperature of 700 °C, with numerous thermal cycles to ambient that were generally related to grid power failures or physical moves of the test apparatus. The power output has remained, with variations due to orientation changes and minor variations due to small temperature changes, essentially constant at 0.40 W to 0.60 W over the test period and operation is ongoing. The converter casing and mechanical structure was fabricated from 316 SS and the electrodes are sputtered titanium nitride films. Separate static tests of a multilayer insulation package suitable for use with the converter showed the capability to reach 700 °C with a thermal input of < 4 watts.

Hunt, T. K.; Rasmussen, J. R.

2006-01-01

214

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.

215

Rapid bridge deck replacement  

E-print Network

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... bridge structures. These methods essentially involve use of epoxy mortar and standard welded shear connectors. The overall method appears to be viable and econom1cal. However, several serious questions, especially regarding structural behav1 or...

Osegueda, Roberto Alejandro

2012-06-07

216

Bridges and Pictures  

Microsoft Academic Search

At the age of 15, with the first single-lens reflex camera of my very own, I naturally took shots of the area around my parent’s\\u000a house. That included the bridge across the Elbe-Trave Canal. I crossed this bridge every day on the way to school and I could\\u000a see it from my room. Of course, it would be going too

Wilfried Dechau

217

Liquid metal thermal electric converter  

DOEpatents

A liquid metal thermal electric converter which converts heat energy to electrical energy. The design of the liquid metal thermal electric converter incorporates a unique configuration which directs the metal fluid pressure to the outside of the tube which results in the structural loads in the tube to be compressive. A liquid metal thermal electric converter refluxing boiler with series connection of tubes and a multiple cell liquid metal thermal electric converter are also provided.

Abbin, Joseph P. (Albuquerque, NM); Andraka, Charles E. (Albuquerque, NM); Lukens, Laurance L. (Albuquerque, NM); Moreno, James B. (Albuquerque, NM)

1989-01-01

218

Germ Cell Intercellular Bridges  

PubMed Central

Stable intercellular bridges are a conserved feature of gametogenesis in multicellular animals observed more than 100 years ago, but their function was unknown. Many of the components necessary for this structure have been identified through the study of cytokinesis in Drosophila; however, mammalian intercellular bridges have distinct properties from those of insects. Mammalian germ cell intercellular bridges are composed of general cytokinesis components with additional germ cell–specific factors including TEX14. TEX14 is an inactive kinase essential for the maintenance of stable intercellular bridges in gametes of both sexes but whose loss specifically impairs male meiosis. TEX14 acts to impede the terminal steps of abscission by competing for essential component CEP55, blocking its interaction in nongerm cells with ALIX and TSG101. Additionally, TEX14-interacting protein RBM44, whose localization in stabile intercellular bridges is limited to pachytene and secondary spermatocytes, may participate in processes such as RNA transport but is nonessential to the maintenance of intercellular bridge stability. PMID:21669984

Greenbaum, Michael P.; Iwamori, Tokuko; Buchold, Gregory M.; Matzuk, Martin M.

2011-01-01

219

Contribution to the AC-analysis of resonant converters; analysis of the series-parallel resonant converter including effects of parasitics and lossless snubbers for optimized design  

Microsoft Academic Search

A stress analysis is performed based on the complex AC-analysis technique for half-bridge resonant power converters. Selecting the series-parallel topology (LCC) for high-power applications with low output voltage, the ideal and the lossy converter are analyzed in the time domain and evaluated by measurements and in comparison to the simplified analysis to find an optimum operating range and design

N. Frohleke; J. Kunze; A. Fiedler; H. Grotstollen

1992-01-01

220

Application of a Modular Multilevel Cascade Converter (MMCC-SDBC) to a STATCOM  

NASA Astrophysics Data System (ADS)

This paper presents the application of a modular multilevel cascade converter based on single-delta bridge-cells (MMCC-SDBC) to a STATic synchronous COMpensator (STATCOM), particularly for negative-sequence reactive-power control. The SDBC is characterized by cascade connection of multiple single-phase H-bridge (or full-bridge) converter cells per leg, which facilitates flexible circuit design, low voltage steps, and low electro-magnetic interference (EMI) emissions. However, there is no published report on such a STATCOM with experimental verification or a control strategy. This paper designs, constructs, and tests a 100-V 5-kVA PWM STATCOM based on the SDBC with focus on the operating principle and performance. Experimental results confirm that this converter can control not only the positive-sequence reactive power but also the negative-sequence reactive power and low-frequency active power intended for the flicker compensation of arc furnaces.

Hagiwara, Makoto; Maeda, Ryo; Akagi, Hirofumi

221

IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 11, NO. 3, MAY 2003 345 Control of a Multilevel Converter  

E-print Network

(acceleration and braking). For parallel-configured HEVs, a cascaded H-bridges multilevel inverter can be used of a Multilevel Converter Using Resultant Theory John N. Chiasson, Member, IEEE, Leon M. Tolbert, Senior Member--In this work, a method is given to compute the switching angles in a multilevel converter to produce

Tolbert, Leon M.

222

36 IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 35, NO. 1, JANUARY/FEBRUARY 1999 Multilevel Converters for Large Electric Drives  

E-print Network

. Multilevel converters: 1) can generate near- sinusoidal voltages with only fundamental frequency switching; 2 because of the high voltampere ratings possible with these inverters [1]. For EV's, a cascaded H- bridges convert this source to variable-frequency ac voltage for the driven motor. Multilevel inverters also solve

Tolbert, Leon M.

223

High Input Voltage Step-Down DC-DC Converters for Integration in a Low Voltage CMOS Process  

Microsoft Academic Search

A cascode bridge circuit for monolithic switching DC- DC converters operating at high input voltages is pro- posed in this paper. The proposed circuit can also be used as an I\\/O buffer to interface circuits operating at signifi- cantly different voltages. The circuit technique permits the full integration of the active and passive devices of a switching DC-DC converter with

Volkan Kursun; Siva Narendra; Vivek De; Eby G. Friedman

2004-01-01

224

Thermionic energy converters  

NASA Technical Reports Server (NTRS)

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.

Morris, J. F. (inventor)

1983-01-01

225

New control scheme for AC-DC-AC converter without DC link electrolytic capacitor  

Microsoft Academic Search

A novel concept for a static three-phase to three-phase power converter for an AC motor drive with unity power factor and reduced harmonics on the utility line is presented. The power circuit consists of two back-to-back connected six-pulse bridges having only a 5-?F ceramic capacitor in the DC link. By controlling the active power balance between two bridges, the DC

J. S. Kim; S. K. Sul

1993-01-01

226

Free FLV Converter  

NSDL National Science Digital Library

Taking Flash files from the web can be a bit cumbersome, so this application will definitely be a most welcome find. This free Flash converter (the second to last link on the left) allows users to take Flash files and transfer them to formats appropriate for portable devices and other items. The site is available in both French and English and this particular version is compatible with computers running Windows 2000, XP, 2003, and Vista.

2007-01-01

227

Purplemath: Cancelling / Converting Units  

NSDL National Science Digital Library

This page contains a step-by-step tutorial in converting between units. It begins with one-step conversions, progressing to problems requiring multiple unit conversion. Areas of frequent student difficulty are given extra attention by the author, who presents the tutorial in an informal writing style designed to engage high school students. This tutorial is part of an award-winning collection of free resources developed to promote understanding and confidence in algebra.

Elizabeth Stapel

228

Multilevel converters -- A new breed of power converters  

SciTech Connect

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.

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

229

Pennsylvania Covered Bridges  

NSDL National Science Digital Library

Covered bridges cause moments of delight for historic preservationists, and they entered a new place in American popular culture when they figured prominently in a certain Clint Eastwood film in the early 1990s. Recently, staff members and student assistants at Bucknell University spent a significant amount of time creating this digital collection of covered bridge photographs. Interestingly enough, the original photographs were taken by a long-time member of the biology faculty at Bucknell, one Professor Nelson F. Davis. The photos date from 1898 to 1939, and all told, there are over 300 images in this collection. Visitors will enjoy looking over this collection, and these documents will be of great interest to anyone fascinated by these types of bridges, engineering, or the history of rural Pennsylvania.

230

Shoreham Railroad Bridge, Title Sheet Shoreham Railroad Bridge, Former ...  

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

Shoreham Railroad Bridge, Title Sheet - Shoreham Railroad Bridge, Former Addison County Railroad (later, Rutland Railroad, Addison Branch), spanning Lemon Fair River above Richville Pond, west of East Shoreham Road, Shoreham, Addison County, VT

231

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

232

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

233

Open-loop approach for control of multi-terminal DC systems based on modular multilevel converters  

Microsoft Academic Search

In this paper a multi-terminal direct current (MTDC) system with modular multilevel converters (M2Cs) is suggested. An open loop control method is used for the control of the converters. Each converter is modeled with 36 sub-modules per arm with a total of 216 sub-modules consisting of half bridges. Power-synchronization control is used instead of a phase-locked loop (PLL) for synchronization.

Arif Haider; Noman Ahmed; Lennart Angquist; Hans-Peter Nee

2011-01-01

234

`Smart bridge' technology helps monitor I-35W bridge behavior  

E-print Network

`Smart bridge' technology helps monitor I-35W bridge behavior Bicycle, pedestrian traffic counts? page 2 SUSTAINABILITY INSIGHTS page 2 TRANSITWAY INFLUENCES ON NEIGHBORHOODS page 3 SMART SIGNAL page 4, University of Minnesota researchers have been using"smart bridge"technology to collect and analyze data about

Minnesota, University of

235

1. WESTERN VIEW OF BRIDGE PLAZA, SHOWING MEMORIAL BRIDGE AT ...  

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

1. WESTERN VIEW OF BRIDGE PLAZA, SHOWING MEMORIAL BRIDGE AT LEFT AND THE ROCK CREEK AND POTOMAC PARKWAY RAMP AT RIGHT. VIEW TAKEN FROM THE REAR OF THE LINCOLN MEMORIAL. - Arlington Memorial Bridge, Boundary Channel Extension, Spanning Mount Vernon Memorial Highway & Boundary Channel, Washington, District of Columbia, DC

236

Evaluating vehicular-induced bridge vibrations for energy harvesting applications  

NASA Astrophysics Data System (ADS)

Highway bridges are vital links in the transportation network in the United States. Identifying possible safety problems in the approximately 600,000 bridges across the country is generally accomplished through labor-intensive, visual inspections. Ongoing research sponsored by NIST seeks to improve inspection practices by providing real-time, continuous monitoring technology for steel bridges. A wireless sensor network with a service life of ten years that is powered by an integrated energy harvester is targeted. In order to achieve the target ten-year life for the monitoring system, novel approaches to energy harvesting for use in recharging batteries are investigated. Three main sources of energy are evaluated: (a) vibrational energy, (b) solar energy, and (c) wind energy. Assessing the energy produced from vehicular-induced vibrations and converted through electromagnetic induction is the focus of this paper. The goal of the study is to process acceleration data and analyze the vibrational response of steel bridges to moving truck loads. Through spectral analysis and harvester modeling, the feasibility of vibration-based energy harvesting for longterm monitoring can be assessed. The effects of bridge conditions, ambient temperature, truck traffic patterns, and harvester position on the power content of the vibrations are investigated. With sensor nodes continually recharged, the proposed real-time monitoring system will operate off the power grid, thus reducing life cycle costs and enhancing inspection practices for state DOTs. This paper will present the results of estimating the vibration energy of a steel bridge in Texas.

Reichenbach, Matthew; Fasl, Jeremiah; Samaras, Vasilis A.; Wood, Sharon; Helwig, Todd; Lindenberg, Richard

2012-04-01

237

Universal Currency Converter  

NSDL National Science Digital Library

The Universal Currency Converter site was developed by Xenon Laboratories. It provides currency conversion for most of the currencies in the world. The conversion rates for the currency are provided by The Bank of Montreal's Treasury Group. Visitors can also obtain a currency table for a selected base currency. The site also provides prices for silver, gold and platinum in the various currencies. Visitors can sign-up for the Currency Update Service which provides free currency table updates specified in the user-selected base currency once every business day.

1998-01-01

238

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.

239

A Novel Control Scheme for Current-Source-Converter-Based PMSG Wind Energy Conversion Systems  

Microsoft Academic Search

A novel control scheme for permanent-magnet synchronous generator is proposed in this paper, where a current-source converter is employed as the bridge between the generator and the grid for high-power wind energy conversion systems. In these medium voltage (2.3-13.8 kV) level applications, current-source converters not only have inherent advantages, but also present some challenges for controller design due to the

Jingya Dai; Bin Wu

2009-01-01

240

A Three-Phase Bidirectional DC-DC Converter for Automotive Applications  

SciTech Connect

This paper presents a three-phase soft-switching, bidirectional dc-dc converter for high-power automotive applications. The converter employs dual three-phase active bridges and operates with a novel asymmetrical but fixed duty cycle for the top and bottom switches of each phase leg. Simulation and experimental data on a 6-kW prototype are included to verify the novel operating and power flow control principles.

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

2008-01-01

241

A closed-loop control of high power LLC Resonant Converter for DC-DC applications  

Microsoft Academic Search

This paper presents a new closed-loop control strategy applied to half-bridge high power LLC Resonant Converter applicable in DC-DC applications and can be applied for other applications also. A new control circuit is designed and implemented for the high power LLC converter. A closed-loop variable frequency control through VCO is analyzed through PI Controller. Due to Zero Voltage Switching (ZVS)

Alpa Gopiyani; Vinod Patel

2011-01-01

242

A Guide to Covered Bridges  

NSDL National Science Digital Library

A Guide to Covered Bridges, offered by Drexel University, Philadelphia, Pennsylvania, transforms the Web into a time machine. Find the answer to the question, why are there so many covered bridges, and why in Pennsylvania and the Northeast? The Drexel University Honors Program sponsors this guide to dozens of covered bridges of the Philadelphia region. Driving tours are suggested, and bridge images are indexed by season (fall color, winter, snow and ice, spring/summer) and structure as well as county.

243

CMOS Bridging Fault Detection  

Microsoft Academic Search

The authors compare the performance of two test generation techniques, stuck fault testing and current testing, when applied to CMOS bridging faults. Accurate simulation of such faults mandated the development of several new design automation tools, including an analog-digital fault simulator. The results of this simulation are analyzed. It is shown that stuck fault test generation, while inherently incapable of

Thomas M. Storey; Wojciech Maly

1990-01-01

244

Partnership Building a Bridge  

E-print Network

will accelerate new ideas into clinical treatments for the prevention and cure of cancer. Cancer Research Clinical efficient translation of new discoveries into clinical treatments for the prevention and cure of cancerCancer Research Clinical Partnership Building a Bridge Between Purdue Discovery and Clinical

245

Bridging the Gender Gap  

E-print Network

Bridging the Gender Gap: Growing the Next Generation of Women in Computing A sobering fact: the U need to ensure our research and development teams are diverse enough to anticipate, respond, and serve Develop: This radically new software development environment lets you write code for your phone on your

Chaudhuri, Surajit

246

Quantum bidding in Bridge  

E-print Network

Quantum methods allow to reduce communication complexity of some computational tasks, with several separated partners, beyond classical constraints. Nevertheless, experimental demonstrations of this fact are thus far 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 advantage in 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 specific form of communication, of a very low complexity (effectively one has a strong limitations on number of exchanged bits). Surprisingly, our quantum technique is not violating 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 (CHSH) game, which is equivalent to a $2\\to 1$ quantum random access code. Thus our experiment is also a realization of such protocols. However, this correspondence is not full which enables the Bridge players to have efficient strategies regardless of the quality of their detectors.

S. Muhammad; A. Tavakoli; M. Kurant; M. Pawlowski; M. Zukowski; M. Bourennane

2014-03-17

247

Bridging a Cultural Gap  

ERIC Educational Resources Information Center

There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes--aimed at bridging the gap between high-school mathematics and tertiary mathematics--is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a…

Leviatan, Talma

2008-01-01

248

Design Squad: Truss Bridge  

NSDL National Science Digital Library

In this video segment adapted from Design Squad—a PBS TV series featuring high school contestants tackling engineering challenges—students employ the concepts of tension and compression as they build a truss bridge without the aid of power tools.

2007-08-09

249

Building Migratory Bridges  

ERIC Educational Resources Information Center

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…

Roy, Michael; Doss, Laurie K.

2007-01-01

250

Bryce Canyon Natural Bridge  

USGS Multimedia Gallery

Bryce Canyon's Natural Bridge is technically a natural arch, similar to those in the nearby Arches National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates...

251

Onyx Bridg e Volcanology  

E-print Network

Carso n Oregon Onyx Bridg e Cascad e Willamette University etuhcseDs BEECH Boyn itseuHs Volcanology on Franklin Blvd until you reach Onyx. 7. Turn right into the Onyx lot, then left towards the end of the lot

252

Onyx Bridg e Volcanology  

E-print Network

Carso n Oregon Onyx Bridg e Cascad e Willamette University etuhcseDs H itseuHs Volcanology (turns into Franklin Blvd) 6. Continue on Franklin Bldv until you reach Onyx (stop light). 7. Turn right into the Onyx lot, then left towards the end of the lot. 8. CAMCOR spots are located halfway down the parking

253

Bridging the Gap.  

ERIC Educational Resources Information Center

Presents a critique of existing methodology used in curriculum updates in academic institutions, suggesting that an integrated approach is more realistic and meaningful to study and to bridging the gap between academic curriculum and industry's needs. Specifically recommends that curriculum-related and job-related data be analyzed simultaneously.…

Mansour, Ali H.; And Others

1986-01-01

254

Bidirectional buck boost converter  

DOEpatents

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.

Esser, A.A.M.

1998-03-31

255

Bidirectional buck boost converter  

DOEpatents

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.

Esser, Albert Andreas Maria (Niskayuna, NY)

1998-03-31

256

Gallium phosphide energy converters  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

257

Fibre reinforced composite dental bridge  

Microsoft Academic Search

This experimental investigation aims at revealing the mechanical behaviour and failure pattern of direct fibre-reinforced resin-bonded dental bridge with various designs. To evaluate the overall effects of some newly developed dental materials, in the experiment, genuine composite dental bridge specimens are prepared and tested. The ultimate load, stiffness and mode at the failure of the bridges are measured and compared

W. Li; M. V. Swain; Q. Li; J. Ironside; G. P. Steven

2004-01-01

258

USGS Gage At Covered Bridge  

USGS Multimedia Gallery

This photograph shows Lowe's Bridge off ME-15 in Guilford, Maine, spanning the Piscataquis River. USGS gaging station 01031500 is located on the downstream side of the bridge. The original bridge, built in 1857, washed away in the flood of 1987, and was rebuilt on the original abutments in 1990....

259

Maintaining Minnesota's Unique Bridge Inventory  

E-print Network

Brinckerhoff Minneapolis, Minnesota Blatnik and Bong Bridges Wire Rope Replacement: #12;Blatnik and Bong Bridges Wire Rope Replacement · Configuration and existing condition of the deck suspender system;Blatnik and Bong Bridges Wire Rope Replacement · In 2007, a fracture critical inspection of the Blatnik

Minnesota, University of

260

Cascaded H-Bridge Multilevel Boost Inverter without Inductors for Electric\\/Hybrid Electric Vehicle Applications  

Microsoft Academic Search

\\u000a This paper presents a cascaded H-bridge multilevel boost inverter for electric vehicle (EV) and hybrid EV (HEV) applications\\u000a implemented without the use of inductors. Currently available power inverter systems for HEVs use a dc–dc boost converter\\u000a to boost the battery voltage for a traditional three-phase inverter. A cascaded H-bridge multilevel boost inverter design\\u000a for EV and HEV applications implemented without

S. Dhayanandh; A. P. Ramya Sri; S. Rajkumar; N. Lavanya

261

Two passivity-based approaches to the control of the H-bridge-based multilevel rectifier  

Microsoft Academic Search

This paper deals with a multilevel H-bridge based front-end rectifier to be used in high voltage high power applications. The main control issue for such type of converter is stabilization. In fact, voltage unbalancing across the distinct DC links can lead to system instability. In this paper two passivity-based control (PBC) algorithms for the H-bridge-based multilevel rectifier are analysed and

Antonio Dell' Aquila; Marco Liserre; Vito G. Monopoli; Paola Rotondo

2003-01-01

262

A novel SVM algorithm for reducing oscillations in cascaded H-bridge multilevel inverters  

Microsoft Academic Search

Cascaded H-bridge inverters have been selected as one of the preferred power converter topologies for high-voltage, high-power applications. However, undesired oscillations could occur in the H-bridge inverter drive system particularly under light load conditions, which would cause high voltage or current stress on the motor and inverter. In this paper, the mechanism of the oscillations is analyzed and a novel

Sanmin Wei; Bin Wu; R. Cheung

2003-01-01

263

Control of cascaded H-bridge inverters using an FPGA-based platform  

Microsoft Academic Search

Cascaded H-bridge multilevel inverters are highly modular converters particularly suitable for generating high output voltages and connecting independent dc sources like solar arrays or fuel cells. Three-phase multilevel inverters based on cascaded H-bridge inverters require a large number of control signals, particularly if the number of levels is high. In this case, Field-Programmable Gate Array appears as the right solution

Emanuel C. Meireles; Antonio P. Martins

2011-01-01

264

Unity power factor converter  

NASA Technical Reports Server (NTRS)

A unity power factor converter capable of effecting either inversion (dc-to-dc) or rectification (ac-to-dc), and capable of providing bilateral power control from a DC source (or load) through an AC transmission line to a DC load (or source) for power flow in either direction, is comprised of comparators for comparing the AC current i with an AC signal i.sub.ref (or its phase inversion) derived from the AC ports to generate control signals to operate a switch control circuit for high speed switching to shape the AC current waveform to a sine waveform, and synchronize it in phase and frequency with the AC voltage at the AC ports, by selectively switching the connections to a series inductor as required to increase or decrease the current i.

Wester, Gene W. (Inventor)

1980-01-01

265

Wave energy converter  

SciTech Connect

A power generation system for converting the motion of waves on a body of water such as a lake or sea to drive pumps, electrical generators or the like. A weighted float rides on the waves. A cable and pulley arrangement changes the direction, travel and force of the wave energy action imparted on the float and drives a hydraulic circuit. The hydraulic circuit includes an accumulator for temporary energy storage and release to assist in maintaining constant flow and pressure of hydraulic fluid to one or more hydraulic motors during each wave cycle. The hydraulic motor drives a load such as an electric generator. An automatically actuated device adjusts for high and low tides.

Taylor, R.N.

1984-02-28

266

Molecular engineering with bridged polysilsesquioxanes  

SciTech Connect

Bridged polysilsesquioxanes are a class of hybrid organic-inorganic materials that permit molecular engineering of bulk properties including porosity. Prepared by sol-gel polymerization of monomers with two or more trialkoxysilyl groups, the materials are highly cross-linked amorphous polymers that are readily obtained as gels. The bridging configuration of the hydrocarbon group insures that network polymers are readily formed and that the organic functionality is homogeneously distributed throughout the polymeric scaffolding at the molecular level. This permits the bulk properties, including surface area, pore size, and dielectric constant to be engineered through the selection of the bridging organic group. Numerous bridging groups have been incorporated. This presentation will focus on the effects that the length, flexibility, and substitution geometry of the hydrocarbon bridging groups have on the properties of the resulting bridged polysilsesquioxanes. Details of the preparation, characterization, and some structure property relationships of these bridged polysilsesquioxanes will be given.

LOY,DOUGLAS A.; SHEA,KENNETH J.

2000-05-09

267

Reliability of long span bridges based on design experience with the Honshu–Shikoku bridges  

Microsoft Academic Search

Most of the existing long span bridges were designed using deterministic concepts and methods. For example, all the seventeen long span bridges constructed in Japan by the Honshu–Shikoku Bridge Authority between Honshu Island and Shikoku Island including ten suspension bridges, five cable-stayed bridges, one arch bridge, and one truss bridge were designed based on the allowable stress design method. Today,

Dan M. Frangopol; Kiyohiro Imai

2004-01-01

268

Electrical Actuation Technology Bridging  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

269

Build a Bridge  

NSDL National Science Digital Library

In this activity, learners use recycled materials to build a bridge that holds as many potatoes as possible. They investigate weight, height, strength, and measurement as they seek design solutions. The activity instructions include ways to adjust the level of challenge for learners of different ages. Try this at family events or to engage all ages. Available as a web page and a downloadable PDF. Students should have the ability to use tape and scissors.

2010-01-01

270

Retrievable bridge plug  

SciTech Connect

This patent describes a retrievable bridge plug apparatus for use in a well conduit. It comprises: body means having first and second ends and an interior passage formed in the body means; gripping means; first and second extending means for extending the gripping means; packing means; first shoulder means; cover means; and tubular means located in the body means and being responsive to movement of the cover means.

Rosenthal, W.O.

1990-02-06

271

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.

272

17.March.2005 C. A. Martins, CERN AB/PO 1 Power converter  

E-print Network

system; · Forced air cooling (no need for water circuit) · Cast resin power transformers. Can be placed, 1000Vdc Converter topology 18 kV cell Power transformers (in an oil tank) 2x4 Rectifier bridges Passive system, type PS #12;17.March.2005 C. A. Martins, CERN AB/PO 10 AB/PO proposition 8000Adc, 1000Vdc Power

McDonald, Kirk

273

Active Clamp Forward Converter Combined with Dither Voltage Generator for Poultry Stunning Applications  

Microsoft Academic Search

This paper presents an intelligent poultry stunner for improving carcass quality and animal welfare. In the stunner system, an active clamp circuit is used in a forward converter to reset the magnetizing energy and to recover leakage energy trapped in the transformer, increasing its conversion efficiency. In addition, a dither generator realized with a half-bridge inverter is adopted to fast

S.-Y. Tseng; H.-T. Wen; H.-H. ChangandJ; J.-S. Kuo

2006-01-01

274

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

SciTech Connect

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.

None

2012-02-23

275

Ocean wave energy converter  

SciTech Connect

This patent describes apparatus for converting the energy of wave motion on the surface of a body of water to electricity comprising: lower structural support means approximately forming edge elements of an equilateral triangle; lower tube receptacles connected to the lower structural support means approximately forming vertex elements of an equilateral triangle; tubular members having upper and lower portions positioned within the tube receptacles approximately forming trimetric edge elements of a right conical frustum; a separable buoyancy device affixed to the upper portions of the tubular members above the lower structural support means, the buoyancy device having upper and lower surfaces and an enclosed space therein; an annulated receptacle plate affixed to the upper surface of the buoyancy device; truncated right circular cylinders connected to the annulated receptacle plate extending outwardly in coaxial alignment with respective tubular members; articulated brackets connected to the annulated receptacle plate in radial extension; upper structural support means connected to the articulated brackets in radial extension for connection to other receptacle plate articulated brackets of a module array; and dual rolling contact support means comprising open linear slide bearings operatively positioned within the tube upper portions and the truncated cylinders.

Ames, P.F.

1987-06-09

276

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.

277

High-frequency resonant transistor dc-dc converters  

NASA Astrophysics Data System (ADS)

The design of a transistor dc-dc resonant converter operating at 200-300 kHz is presented, and the operation of a 500-W breadboard version is reported. Several configurations of both voltage-input and current-input type are described and illustrated with circuit diagrams and waveforms, and a full-bridge voltage-input resonant inverter using gate turnoff devices is analyzed in detail, using a piecewise linear approach to obtain design curves. The performance of the breadboard voltage-input half bridge using FET power switches is shown in graphs, demonstrating the low switching losses and transistor stresses achieved by lossless-snubber design. It is predicted that similar designs using bipolar transistors or GTOs can attain energy efficiencies greater than 90 percent. Applications to switching power supplies and battery chargers are suggested.

Steigerwald, R. L.

1984-05-01

278

Hybrid Cascaded H-bridges Multilevel Motor Drive Control for Electric Vehicles  

Microsoft Academic Search

This paper presents a hybrid cascaded H-bridge multilevel motor drive control scheme for electric\\/hybrid electric vehicles where each phase of a three-phase cascaded multilevel converter can be implemented using only a single DC source and capacitors for the other DC sources. Traditionally, each phase of a three-phase cascaded multilevel converter requires n DC sources for 2n + 1 output voltage

Zhong Du; Leon M. Tolbert; John N. Chiasson; Burak Ozpineci; Hui Li; Alex Q. Huang

2006-01-01

279

An Optimized Control Technique of Cascaded H-bridge Multilevel Active Front-ends  

Microsoft Academic Search

The paper is devoted to the investigation of a three-phase multilevel H-bridge PWM-Rectifier operating as a first stage of a back-to-back converter in high-power ac drives. First, a predictive control technique is described with reference to a 5-level converter. Starting from properly defined reference values, the algorithm pointed out allows the direct evaluation of the duty-cycles of all the voltage

Gianluca Brando; Adolfo Dannier; Andrea Del Pizzo

2006-01-01

280

The active-bridge oscillator  

SciTech Connect

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.

Wessendorf, K.O.

1998-07-01

281

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.

282

PWM Converter Power Density Barriers  

Microsoft Academic Search

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

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

2007-01-01

283

Inverse dual converter (IDC) for high power dc-dc applications  

NASA Astrophysics Data System (ADS)

The inverse dual converter (IDC), suitable for high-power dc-dc conversion applications, is presented. The IDC is a voltage source converter with an ac link and has been derived from an inductor converter bridge. This capacitor commutated converter is capable of continuous voltage step-up or step-down control over a wide range without the need of a transformer. In addition to high-frequency switching the converter is characterized by soft switching techniques, reducing constraints on the ratings of the switches. The average model developed with the help of gyrator theory provides sufficient information for control strategies and design considerations. The results of gyrator modeling and computer simulation are compared with experimental results obtained from a prototype IDC.

Ehsani, M.; Husain, I.; Bilgic, M. O.

284

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.

1999-01-01

285

The Adaptive Use Bridge Project  

NSDL National Science Digital Library

The Adaptive Use Bridge Project website is a repository for work being conducted at the University of Massachusetts, Amherst, in which historic iron bridges are rehabilitated, documented, and analyzed. The purpose of the project is to preserve the civil engineering heritage of New England and to develop instructional material for use in undergraduate civil engineering curricula. Upon completion of this long-term project, a protocol for adaptive pedestrian use of historic bridges will be created.

University of Massachusetts, Amherst

286

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 41, NO. 1, JANUARY/FEBRUARY 2005 75 Elimination of Harmonics in a Multilevel Converter  

E-print Network

of Harmonics in a Multilevel Converter With Nonequal DC Sources Leon M. Tolbert, Senior Member, IEEE, John N Abstract--Eliminating harmonics in a multilevel converter in which the separate dc sources vary. Work was re- ported in [1] and [2] that presented a method to compute the switching angles for the H-bridges

Tolbert, Leon M.

287

West Point Bridge Design Contest  

NSDL National Science Digital Library

The second annual West Point Bridge Design Contest concluded in May 2003. Although it is uncertain whether the contest will receive funding for future competitions, its Web site has a number of educational resources for middle and high school students. The main feature is the bridge design software, which allows the user to "model, test, and optimize a steel highway bridge, based on realistic specifications, constraints, and performance criteria." Completed designs can be submitted online for unofficial judging. The book, Designing and Building File-Folder Bridges, can also be freely downloaded. [CL

288

BridgeSPA: Improving Tor Bridges with Single Packet Authorization  

E-print Network

BridgeSPA: Improving Tor Bridges with Single Packet Authorization Rob Smits rdfsmits@cs.uwaterloo.ca ABSTRACT Tor is a network designed for low-latency anonymous com- munications. Tor clients form circuits these circuits. This indirection makes it difficult for a local adversary to determine with whom a particular Tor

Hengartner, Urs

289

The floating water bridge The floating water bridge  

E-print Network

properties and is also the reason why water must not be treated as a simple liquid [1,2]. The interactionThe 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

Podgornik, Rudolf

290

16. Little Hell Gate Bridge with Big Hell Gate Bridge ...  

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

16. Little Hell Gate Bridge with Big Hell Gate Bridge in background. Wards Island, New York Co., NY. Sec. 4207, MP 8.02. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York, New York County, NY

291

20. Bronx Kill Bridge with Hell Gate Bridge in background. ...  

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

20. Bronx Kill Bridge with Hell Gate Bridge in background. Randalls Island, New York Co., NY. Sec. 4207, MP 8.54. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York, New York County, NY

292

An integrated high power factor three-phase AC-DC-AC converter for AC-machines implemented in one microcontroller  

Microsoft Academic Search

A high power factor three-phase AC-DC-AC power converter for AC machines has been designed and tested. The AC-DC-AC converter is controlled by one single 16-b microcontroller. The converter has two PWM-VSI bridges with common snubber- and drive-circuit topologies. The high power factor rectifier is space vector controlled and the inverter controls an AC-induction machine by an energy optimized strategy. Common

Frede Blaabjerg; John K. Pedersen

1993-01-01

293

A novel phase-shift bidirectional DC-DC converter with an extended high-efficiency range for 20 kVA solid state transformer  

Microsoft Academic Search

This paper proposes a novel phase-shift dual-half-bridge converter with an adaptive inductor. This converter will be used as a high frequency transformer isolated dc-dc stage of a 20 kVA single phase solid state transformer (SST) in the future renewable electric energy delivery and management Systems. By utilizing an adaptive inductor as the commutation inductor, the proposed converter can control not

Haifeng Fan; Hui Li

2010-01-01

294

Performance of an angular flange aeroelastic wind energy converter  

SciTech Connect

ALL conventional wind turbines operate on the principles of turbomachinaries, with wind being made to flow over a set of rotating vanes. Recently, a new concept for wind energy conversion based on aeroelastic instability was introduced. It is well known that couplings between the vibration of an elastic structure and fluid stream may lead to aeroelastic instability. Energy then is transferred from the airstream into the elastic structure, which results in a destructive monotonic increase of the vibration amplitude of the structure. The failure of the Tacoma Narrows Bridge is one of the well-known examples of such a disaster. The use of an aeroelastic instability (or flutter) mechanism for constructing a wind energy converter was suggested. The theory for a torsional wind energy converter and the results of some model tests were also presented. Recently, some studies on similar types of wind energy converters using oscillating airfoils were reported. In the present study an angular flange H-section model of a torsional aeroelastic wind energy converter is constructed, and its performances under various conditions are investigated. The effects of the variations of the flange angle and the flange width on the performance of the model are studied. The weight of the pendulum is also varied, and its effects on the power coefficient of the model are investigated. It is observed that the efficiency of energy conversion decreases with an increase in wind speed. A method for possible improvement of the theoretical prediction is suggested and discussed.

Ahmadi, G.

1983-05-01

295

Trigenomic Bridges for Brassica Improvement  

Microsoft Academic Search

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,

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

296

Bridging properties of multiblock copolymers.  

SciTech Connect

Using self-consistent field theory, we attempt to elucidate the links between microscopically determined properties, such as the bridging fraction of chains, and mechanical properties of multiblock copolymer materials. We determine morphological aspects such as period and interfacial width and calculate the bridging fractions, and compare with experimental data .

Rasmussen, K. O. (Kim O.); Kober, E. M. (Edward M.); Lookman, T. (Turab); Saxena, A. B. (Avadh B.)

2003-01-01

297

BRIDGES AND NETWORKS: EXACT ASYMPTOTICS  

Microsoft Academic Search

We extend the Markov additive methodology developed in (1, 3) to obtain the sharp asymptotics of the steady state probability of a queueing network when one of the nodes gets large. We focus on a new phenomenon we call a bridge. The bridge cases occur when the Markovian part of the twisted Markov additive process is one null recurrent or

ROBERT D. FOLEY; DAVID R. MCDONALD

2004-01-01

298

Typical Bridge Foundations - Selected Cases  

Microsoft Academic Search

Foundations of the bridges have always been a matter of great concern to Civil Engineers. In many instances actual strata met with at the foundation level turned out to be quite different than that found at the time of geological and geotechnical investigation. This paper discusses typical case studies of bridge foundations constructed at various places in the state of

P. K. Jain; Rakesh Kumar; Anand Selot; S. K. Mittal

299

Model predictive control for Cascaded H-bridge multilevel inverters with even power distribution  

Microsoft Academic Search

Cascaded H-bridge inverters are commonly controlled using linear control and Phase Shifted Pulse Width Modulation, since it allows an even power distribution among the cells, which reduces the harmonic distortion by means of isolation phase-shifted transformers. Recently, predictive control schemes for power electronic converters have been developed, featuring its simplicity, flexibility using different control objectives and an improved dynamic performance.

Alan Wilson; P. Corte?s; Samir Kouro; J. Rodri?guez; H. Abu-Rub

2010-01-01

300

CRIME BULLETIN INCIDENT: Catalytic Converter Thefts  

E-print Network

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

Barrett, Jeffrey A.

301

Bridge Building: Art and Science  

NSDL National Science Digital Library

This site is one of the most substantial, comprehensive sources on the Internet dedicated to bridge design and history. It has an incredible list of sections from which to choose, and each describes a particular bridge type or characteristic. Several pictures are included from all over the world that give examples of arch, truss, suspension, and many other bridge designs. There are also explanations of forces that act upon bridges, as well as what issues are considered when choosing the kind of bridge to build over a span. Perhaps the only drawback to the site is that there is so much information; the main page seems a bit cluttered. However, it does not really hamper navigating the site.

302

Converting Petroleum Coke to Electricity  

E-print Network

. This paper presents the operating history of US based plants converting petroleum coke to electricity, and presents generic economics for the conversion process utilizing three primary technologies available: conventional pulverized coke combustion...

Pavone, A.

303

Thermoionic converter for space Reactor  

Microsoft Academic Search

Thermionic converters offer many advantages for use as space reactors. Over the last several years, six experiments were performed, of which four were in-pile experiments and two out-pile experiments. Of the four in-pile experiments, three involved the use of three converters linked in series. The use of nuclear reactors as the power source for an electrical system in space is

Shengquan Cao; Jicai Yang

1990-01-01

304

Construction Technologies: Construct the Strongest Bridge  

NSDL National Science Digital Library

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.

2014-08-06

305

Burning trees and bridges  

NASA Technical Reports Server (NTRS)

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.

Levine, Joel S.

1990-01-01

306

Bridges to Structure  

NSDL National Science Digital Library

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.

Peter Woodruff (Champlain-St. Lambert College;); Joyce Cadawallader (Saint-Mary-of-the-Woods College;)

2004-06-12

307

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.

308

Input-series common transformer connected PS-FB DC-DC converters for pulsed MIG welding  

Microsoft Academic Search

A pulsed Metal Inert Gas (PMIG) welding system is built based on the input-series common transformer connected phase-shifted full-bridge (PS-FB) DC\\/DC converters. Because the input-series connected converters share the same transformer magnetic core, equal sharing of input voltage can be achieved automatically without special voltage sharing control. To enhance the reliability of the system, a hybrid peak current control strategy

Xiaoqing Song; Deshang Sha; Xiaozhong Liao

2012-01-01

309

High efficiency bidirectional LLC resonant converter for 380V DC power distribution system using digital control scheme  

Microsoft Academic Search

A bidirectional full-bridge LLC resonant converter with a new symmetric LLC-type resonant network using a digital control scheme is proposed for a 380V dc power distribution system. This converter can operate under high power conversion efficiency since the symmetric LLC resonant network has zero voltage switching capability for primary power switches and soft commutation capability for output rectifiers. In addition,

Jee-Hoon Jung; Ho-Sung Kim; Jong-Hyun Kim; Myoung-Hyo Ryu; Ju-Won Baek

2012-01-01

310

Active clamp interleaved forward converter with single-capacitor turn-off snubber for stunning poultry applications  

Microsoft Academic Search

This paper proposes an active clamp interleaved forward converter with a single-capacitor turn-off snubber constructed with a full-bridge inverter for stunning poultry applications. The proposed converter can use active clamp circuit to recover the energy trapped in magnetizing and leakage inductors of transformer and to achieve zero-voltage switching at turn-on transition. In addition, the proposed one adopts a single-capacitor snubber

S.-Y. Tseng; C.-T. Hsieh; H.-C. Lin

2008-01-01

311

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

Microsoft Academic Search

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

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

2008-01-01

312

Test and evaluation of load converter topologies used in the Space Station Freedom Power Management and distribution DC test bed  

NASA Technical Reports Server (NTRS)

Power components hardware in support of the Space Station Freedom dc Electrical Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switchmode converter, and a switching full-bridge forward converter. The topology, operation principles, and tests results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics.

Lebron, Ramon C.; Oliver, Angela C.; Bodi, Robert F.

1991-01-01

313

Test and evaluation of load converter topologies used in the Space Station Freedom power management and distribution dc test bed  

NASA Technical Reports Server (NTRS)

Power components hardware in support of the Space Station freedom dc Electric Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switch-mode converter, and a switching full-bridge forward converter. The topology, operation principles, and test results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics.

Lebron, Ramon C.; Oliver, Angela C.; Bodi, Robert F.

1991-01-01

314

Smart measurement system for resistive (bridge) or capacitive sensors  

NASA Astrophysics Data System (ADS)

A low-cost smart measurement system for resistive (bridge) and capacitive sensors is presented and demonstrated. The measurement system consists of three main parts: the sensor element, a universal transducer interface (UTI) and a microcontroller. The UTI is a sensor-signal-to-time converter, based on a period-modulated oscillator, which is equipped with front-ends for many types of resistive (bridge) and capacitive sensors, and which generates a microcontroller-compatible output signal. The microcontroller performs data acquisition of the output signals from the interface UTI, controls the working status of the UTI for a specified application and communicates with a personal computer. Continuous auto-calibration of the offset and the gain of the complete system is applied to eliminate many nonidealities. Experimental results show that the accuracy and resolution are 14 bits and 16 bits, respectively, for a measurement time of about 100 ms.

Wang, Guijie; Meijer, Gerard C. M.

1998-07-01

315

Control of a Single-Phase Cascaded H-Bridge Multilevel Inverter for Grid-Connected Photovoltaic Systems  

Microsoft Academic Search

This paper presents a single-phase cascaded H-bridge converter for a grid-connected photovoltaic (PV) application. The multilevel topology consists of several H-bridge cells connected in series, each one connected to a string of PV modules. The adopted control scheme permits the independent control of each dc-link voltage, enabling, in this way, the tracking of the maximum power point for each string

Elena Villanueva; Pablo Correa; José Rodríguez; Mario Pacas

2009-01-01

316

Rapid Repair of Low Volume Bridges  

E-print Network

using a gunpowder gun (Arora, 2003) 8(Bank, 2004) #12;Previous MF-FRP Applications · Application tested in Missouri with plans to strengthen up to 31 more bridges (Bank, Nanni, & Arora, 2004) (Rizzo A. , Galati Missouri Bridge No. 1330005 $16,502 688 ft Missouri Bridge No. 3855006 $13,115 666 ft Missouri Bridge No. B

Russell, Jeffrey S.

317

Geology Fieldnotes: Natural Bridges National Monument, Utah  

NSDL National Science Digital Library

This site describes how natural bridges form in crossbedded sandstone, the three stages of bridge maturity, and the differences between bridges and arches. Also included are photographs, park maps, visitor information, and details on the discovery of the Owachomo, Sipapu, and Kachina Bridges.

318

Washed Out Bridge, Snake Creek Near Whitesburg  

USGS Multimedia Gallery

Tributary to Snake Creek, near Whitesburg, Georgia, showing a washed out bridge. When bridges such as this one collapse during a flood, it is rarely the pressure of the rushing water against the bridge that causes the bridge to fail. Rather, the rushing water erodes the ground underneath and surroun...

2009-10-01

319

Pulse excitation of bolometer bridges  

NASA Technical Reports Server (NTRS)

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.

Rusk, S. J.

1972-01-01

320

Bridging the urological divide  

PubMed Central

The advanced disease clinical presentations, higher morbidity and mortality rates and lack of available treatment options in prostate cancer care, attest to disparities in the delivery and outcomes of urological services in Black men of African lineage in both the Developed and Developing countries. This gap in health care and services in the global management of prostate cancer denotes the urological divide. Through the experience of a Developing country urologist with a comparative literature review, this presentation defines the determinants of the disparity through deficiencies in human, material and financial resources, as is most prevalent in Developing countries. Solutions to ending health care disparities must take into account the existing development phase of Third World countries and thus determine whether the Developed countries should export a total service delivery system or seek primarily to advance the competence and skills of the existing Developing country resources. Collaboration in prostate cancer research has the greatest promise and sustainability of bridging this urological divide and is of mutual benefit to both entities. PMID:21992183

2011-01-01

321

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.

322

High efficiency thermionic converter studies  

NASA Technical Reports Server (NTRS)

Research in thermionic energy conversion technology is reported. The objectives were to produce converters suitable for use in out of core space reactors, radioisotope generators, and solar satellites. The development of emitter electrodes that operate at low cesium pressure, stable low work function collector electrodes, and more efficient means of space charge neutralization were investigated to improve thermionic converter performance. Potential improvements in collector properties were noted with evaporated thin film barium oxide coatings. Experiments with cesium carbonate suggest this substance may provide optimum combinations of cesium and oxygen for thermionic conversion.

Huffman, F. N.; Sommer, A. H.; Balestra, C. L.; Briere, T. R.; Lieb, D.; Oettinger, P. E.; Goodale, D. B.

1977-01-01

323

Stirling Converters For Solar Power  

NASA Technical Reports Server (NTRS)

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.

Shaltens, Richard K.; Schreiber, Jeffrey G.

1993-01-01

324

The IBM 8209 LAN bridge  

Microsoft Academic Search

The issues involved in bridging 802.5 (token-ring) and 802.3 (Ethernet) networks at the media access control (MAC) layer are discussed. The issues concern incompatibilities between the two networks in six areas: routing schemes, station addresses, frame formats, and local area network speeds. An approach incorporated in the IBM 8209 LAN bridge for resolving the incompatibilities is described. The IBM 8209

A. Latif; E. J. Rowlance; R. H. Adams

1992-01-01

325

GAUVREAU, The Three Myths of Bridge Aesthetics, 1/8 THE THREE MYTHS OF BRIDGE AESTHETICS  

E-print Network

GAUVREAU, The Three Myths of Bridge Aesthetics, 1/8 THE THREE MYTHS OF BRIDGE AESTHETICS Paul wisdom on bridge aesthetics. If bridge design is to be recognized as a valid and distinct means taste". The conventional wisdom on bridge aesthetics, however, is actually nothing more than such a set

Gauvreau, Paul

326

Performance of a Voltage Step-Up/Step-Down Transformerless DC/DC Converter: Analytical Model  

NASA Astrophysics Data System (ADS)

The authors present an analytical model for a voltage step-up/step-down DC/DC converter without transformers. The proposed topology is a combination of classic buck and boost converters in one single circuit but with differing operational principles. The converter is developed for a wind power autonomous supply system equipped with a hydrogen electrolytic tank and a fuel cell for energy stabilization. The main power source of the hydrogen-based autonomous supply system is energized by a synchronous generator operating on permanent magnets and equipped with a diode bridge. The input voltage of the converter in this case varies in the range 0-700 V, while its output DC voltage must be 540 V according to the demand of other parts of the system. To maintain the rated voltage, a special electrical load regulation is introduced. The calculations of the converter, the generator (equipped with a diode bridge) as element of the power system supply joint, and the load replaced by resistance are verified with PSIM software.

Suskis, P.; Rankis, I.

2012-01-01

327

Sacrificial bridges for MEMS fabrication  

NASA Astrophysics Data System (ADS)

This study discusses sacrificial bridges that are used to release MEMS devices. Before being released, sacrificial bridges connect all the component structures into an integral structure. Solder bump bonding is used to mount the MEMS chip on another chip or a printed circuit board (PCB) and to maintain the alignment among all component structures after removal of the sacrificial bridges. Two types of sacrificial bridges were designed, analyzed and fabricated. The fabrication process—which used low resistivity single crystal silicon (SCS) wafers as the device material—was developed to implement the sacrificial bridges. Novel SCS through silicon vias (TSVs), which interconnect stacked chips, was made using the same process. An electrostatic comb drive actuator was fabricated and mounted onto a PCB. The fabricated actuator was tested to demonstrate the feasibility of the fabrication process, sacrificial bridges and SCS TSVs. The results show that the actuator worked well. Its maximum displacement and resonant frequency were 69.9 µm and 406 Hz, respectively. This method is promising for the delivery of a novel 3D system in package for MEMS devices.

Chang, Chao-Min; Chen, Yang-Che; Fong, Chien-Fu; Guu, Yunn-Horng; Chen, Rongshun; Yeh, J. Andrew; Hou, Max T.

2011-09-01

328

Boron-boron ?-bond formation by two-electron reduction of a H-bridged dimer of monoborane.  

PubMed

Diborane(6) as a H-bridged dimer of monoborane can be converted cleanly by two-electron reduction into diborane(6) dianion, which is isoelectronic with ethane, through B-B ?-bond formation when each boron atom has a bulky ligand on it. The existence of the B-B ? bond is supported by the X-ray molecular structure [B-B bond length of 1.924(3) Å], NMR studies, magnetic susceptibility measurements, and DFT calculations. Stepwise hydride abstraction reactions of the diborane(6) dianion produce the corresponding H-bridged diborane(5) anion and doubly H-bridged diborane(4) without B-B bond scission. PMID:21711029

Shoji, Yoshiaki; Matsuo, Tsukasa; Hashizume, Daisuke; Gutmann, Matthias J; Fueno, Hiroyuki; Tanaka, Kazuyoshi; Tamao, Kohei

2011-07-27

329

Safe-commutation principle for direct single-phase AC-AC converters for use in audio power  

E-print Network

Safe-commutation principle for direct single-phase AC-AC converters for use in audio power-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source is certainly the audio power amplification. Switching-mode Class D audio power amplifiers are becoming

330

Topological constraints on basic PWM converters  

Microsoft Academic Search

A modeling and synthesis technique is introduced for single-ended, ladder-structured, DC-DC converter topologies. Topological constraints are derived that enhance the understanding of structural properties of converter circuits and clarify the roles of inductors and capacitors in various converters using magnetic or capacitive energy storage\\/transfer mechanism. The exact duality relationships among the basic converter topologies are established.

Kwang-Hwa Liu; F. C. Lee

1988-01-01

331

Integrated magnetic for LLC resonant converter  

Microsoft Academic Search

A new LLC resonant converter is proposed for front end DC\\/DC conversion in a distributed power system. This converter shows some potential benefits in this application. This paper proposes several integrated magnetic designs for LLC resonant converter. This converter has three magnetic components. With magnetic integration, first, a number of components can be reduced; secondly, flux ripple cancellation is achieved

Bo Yang; Rengang Chen; Fred C. Lee

2002-01-01

332

Multilevel converters for power system applications  

SciTech Connect

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.

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

333

NONLINEAR-CARRIER CONTROL FOR HIGH-POWER-FACTOR RECTIFIERS BASED ON  

E-print Network

CONVERTERS Regan Zane and Dragan MaksimoviC Power Electronics Group Department of Elect,rical and Computer based on flyback, Cuk or Sepic converters operated in the continuous conduction mode. In the NLC con, flyback, Cuk and Sepic converters offer the benefits of single-stage transformer isolation, voltage step

334

Step-Down Piezoelectric Transformer for AC-DC Converters  

NASA Astrophysics Data System (ADS)

In this paper, a new piezoelectric transformer for AC-DC converters is presented. This piezoelectric transformer, with a multilayered construction in the thickness direction, operates in a fundamental contour-extensional vibration mode. Output impedance is designed to be low, approximately several tens of ohms. First, we simulated the design of the transformer using equivalent circuit method and finite element method (FEM) analyses. We calculated that the transformer could work with an eficiency higher than 95% and a gain of 0.4 at a resonant frequency of 140 kHz. Second, we fabricated a transformer of 14 mm length, 14 mm width and 5.8 mm thickness and examined it. It was found that the transformer exhibited a 0.4 gain and 96.3% efficiency at 135 kHz, when the temperature increase was 30^\\circC@. We applied the transformer to the fabrication of an AC-DC converter using a half-bridge zero voltage switching circuit, and examined the converter. It was found to achieve good line and load regulation, and the highest efficiency of 90% was obtained for Vin=80--120 Vac, Vout=13 Vdc, and Iout= 0.8--1.5 A@.

Yamamoto, Mitsuru; Sasaki, Yasuhiro; Ochi, Atsushi; Inoue, Takeshi; Hamamura, Sunao

2001-05-01

335

Fully phosphor-converted LEDs with Lumiramic phosphor technology  

NASA Astrophysics Data System (ADS)

Fully phosphor-converted LEDs (FpcLeds) with saturated emission have been realized in the green and amber spectral region. With the Lumiramic phosphor technology it is possible to achieve high package efficiency with minimum transmission of blue light from the primary LED source. This is done by keeping the scattering properties of the phosphor layer low while the phosphor thickness is chosen to fully convert all blue LED emission. It is shown that this can be done not only for optically isotropic Lumiramic materials like garnets, but also for oxonitridosilicate materials like the green emitting Europium doped SrSi2O2N2, crystallizing in a triclinic lattice with three optical axes. The scattering power of the Lumiramic can be decreased to acceptable levels by increasing the size of the crystallites in the densely sintered ceramics. Light propagation is found to be described well with Mie scattering of mono-sized SrSi2O2N2 spheres with refraction index differing by 0.07 to the refractive index of a SrSi2O2N2 matrix material. Using this technology, the green-yellow gap of visible light emitting LEDs can be bridged and color tunable lamps with the efficiency and flux of today's white phosphor-converted LEDs become feasible.

Bechtel, Helmut; Schmidt, Peter J.; Tücks, Andreas; Heidemann, Matthias; Chamberlin, Danielle; Müller-Mach, Regina; Müller, Gerd O.; Shchekin, Oleg

2010-08-01

336

High-power converters for space applications  

NASA Astrophysics Data System (ADS)

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.

Park, J. N.; Cooper, Randy

1991-06-01

337

High-power converters for space applications  

NASA Technical Reports Server (NTRS)

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.

Park, J. N.; Cooper, Randy

1991-01-01

338

Charge-pump voltage converter  

DOEpatents

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.

Brainard, John P. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

2009-11-03

339

A novel interferometric wavelength converter  

Microsoft Academic Search

The fiber Kerr effect employment in a wavelength conversion version, owing to low silica nonlinearity, has been prevented by the lack of an efficient interferometric architecture. A novel all-fiber wavelength converter is presented and characterized. The proposed scheme while taking advantage of the Kerr effect properties in standard communication optical fiber overcomes classical interferometric structure limitations, such as high environmental

Pierpaolo Boffi; Lucia Marazzi; Mario Martinelli

1999-01-01

340

State controller for buck converter  

Microsoft Academic Search

The average state space model of the buck converter has been used in order to design the PI and state controller. Simple analytical expressions in terms of the circuit components are derived for frequency responses of time averaged (continuous) power-stage for use in designing and understanding the behavior of corresponding switched power stage. Such obtained models enable the designing of

Suzana Uran; M. Milanovic

2003-01-01

341

BRIDGE BUILDER WILLIAM FLINN?S ?CAMP & BRIDGE BUILDING OUTFIT?. INTERIOR ...  

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

BRIDGE BUILDER WILLIAM FLINN?S ?CAMP & BRIDGE BUILDING OUTFIT?. INTERIOR VIEW SHOWING BUSINESS DESK. - Clear Fork of Brazos River Suspension Bridge, Spanning Clear Fork of Brazos River at County Route 179, Albany, Shackelford County, TX

342

BRIDGE BUILDER WILLIAM FLINN?S ?CAMP & BRIDGE BUILDING OUTFIT?. EXTERIOR ...  

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

BRIDGE BUILDER WILLIAM FLINN?S ?CAMP & BRIDGE BUILDING OUTFIT?. EXTERIOR VIEW. - Clear Fork of Brazos River Suspension Bridge, Spanning Clear Fork of Brazos River at County Route 179, Albany, Shackelford County, TX

343

BRIDGE BUILDER WILLIAM FLINN?S ?CAMP & BRIDGE BUILDING OUTFIT?. INTERIOR ...  

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

BRIDGE BUILDER WILLIAM FLINN?S ?CAMP & BRIDGE BUILDING OUTFIT?. INTERIOR VIEW SHOWING LABORERS AT MEAL TIME. - Clear Fork of Brazos River Suspension Bridge, Spanning Clear Fork of Brazos River at County Route 179, Albany, Shackelford County, TX

344

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

Microsoft Academic Search

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

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

1987-01-01

345

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

Microsoft Academic Search

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

Kenichiro Sano; Hideaki Fujita

2008-01-01

346

23 CFR 650.409 - Evaluation of bridge inventory.  

Code of Federal Regulations, 2010 CFR

...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)...

2010-04-01

347

23 CFR 650.307 - Bridge inspection organization.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

348

23 CFR 650.307 - Bridge inspection organization.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

349

23 CFR 650.409 - Evaluation of bridge inventory.  

Code of Federal Regulations, 2011 CFR

...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)...

2011-04-01

350

23 CFR 650.409 - Evaluation of bridge inventory.  

Code of Federal Regulations, 2013 CFR

...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)...

2013-04-01

351

23 CFR 650.409 - Evaluation of bridge inventory.  

...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)...

2014-04-01

352

23 CFR 650.307 - Bridge inspection organization.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

353

23 CFR 650.307 - Bridge inspection organization.  

...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...

2014-04-01

354

23 CFR 650.409 - Evaluation of bridge inventory.  

Code of Federal Regulations, 2012 CFR

...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)...

2012-04-01

355

23 CFR 650.307 - Bridge inspection organization.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

356

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

357

Portable convertible blast effects shield  

DOEpatents

A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more frusto-conically-tapered telescoping 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 by the friction fit of adjacent pairs of frusto-conically-tapered rings to each other.

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)

2011-03-15

358

Reducing catalytic converter pressure loss  

SciTech Connect

This article examines why approximately 30--40% of total exhaust-system pressure loss occurs in the catalytic converter and what can be done to reduce pressure loss. High exhaust-system backpressure is of concern in the design of power trains for passenger cars and trucks because it penalizes fuel economy and limits peak power. Pressure losses occur due to fluid shear and turning during turbulent flow in the converter headers and in entry separation and developing laminar-flow boundary layers within the substrate flow passages. Some of the loss mechanisms are coupled. For example, losses in the inlet header are influenced by the presence of the flow resistance of a downstream substrate. Conversely, the flow maldistribution and pressure loss of the substrate(s) depend on the design of the inlet header.

NONE

1996-06-01

359

Portable convertible blast effects shield  

SciTech Connect

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.

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

360

Portable convertible blast effects shield  

DOEpatents

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.

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

361

Construction Technologies: Create the Strongest Bridge  

NSDL National Science Digital Library

Students work in pairs to create three simple types of model bridges (beam, arch, suspension). They observe quantitatively how the bridges work under load and why engineers use different types of bridges for different places. They also get an idea of the parts needed to build bridges, and their functions. The strength of model bridges is mainly a factor of the quality of materials used, and therefore they do not provide a clear visual representation of tension and compression forces involved. Yet, students are able to see these forces at work in three prototype designs and draw conclusions about their dependence on span, width and supporting structures of the bridge designs.

2014-09-18

362

Microenergy Converter Using Insect Wings  

Microsoft Academic Search

This paper is concerned with the development of novel type of micro wind energy converter using insect wings. A series of\\u000a experimental studies are made on the function of wing apparatus of flying insects. In the first place, the structural properties\\u000a of insect wings are studied through measurements of certain morphological parameters. The scanning electron microscopic observation\\u000a of an insect

Seiichi Sudo; Kazumasa Nashimoto; Koji Tsuyuki; Tetsuya Yano; Muneo Futamura

363

Green phosphor-converted LED  

Microsoft Academic Search

Green phosphor-converted LEDs using a blue pump InGaN diodes have advantages over the direct green InGaN LED with regards to color stability with drive and\\/or temperature. Added manufacturing steps are outweighed by higher color yield, as a range of pump colors can be used without changing the final chromaticity. The conversion losses can be smaller than the decrease in wall-plug

Regina Mueller-Mach; Gerd O. Mueller; Troy A. Trottier; Michael R. Krames; A. Kim; Dan A. Steigerwald

2002-01-01

364

Nonlinear models of suspension bridges  

NASA Astrophysics Data System (ADS)

Nonlinear variational equations describing one type of suspension bridges are proposed and studied. The variational equations describe the behaviour of road bed, main cables and cable stays. The road bed is described by two functions connected with vertical and horizontal deformation of any cross section. The main cable is considered to be perfectly flexible and inextensible. The cable stays only resist tensile forces. The variational equations are derived from the principle of minimum potential energy. The existence of solution is based on the Brouwer Fixed Point Theorem. The local uniqueness and continuous dependence on the data represented by gravitational forces acting on the road bed are studied. The local results are based on the Implicit Function Theorem for Banach spaces. A certain stability criterion for suspension bridges is formulated and this criterion indicates how to influence the stability of suspension bridges.

Malik, Josef

2006-09-01

365

High efficiency thermionic converter studies  

NASA Technical Reports Server (NTRS)

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.

Huffman, F. N.; Sommer, A. H.; Balestra, C. L.; Briere, D. P.; Oettinger, P. E.

1976-01-01

366

2.NBT Toll Bridge Puzzle  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: The picture shows islands connected by bridges. To cross a bridge, you must pay a toll in coins. If you start on the island marked in blue with 100 coi...

2012-07-20

367

Balanced bridge feedback control system  

NASA Technical Reports Server (NTRS)

In a system having a driver, a motor, and a mechanical plant, a multiloop feedback control apparatus for controlling the movement and/or positioning of a mechanical plant, the control apparatus has a first local bridge feedback loop for feeding back a signal representative of a selected ratio of voltage and current at the output driver, and a second bridge feedback loop for feeding back a signal representative of a selected ratio of force and velocity at the output of the motor. The control apparatus may further include an outer loop for feeding back a signal representing the angular velocity and/or position of the mechanical plant.

Lurie, Boris J. (inventor)

1990-01-01

368

Inductorless DC-AC Cascaded H-Bridge Multilevel Boost Inverter for Electric\\/Hybrid Electric Vehicle Applications  

Microsoft Academic Search

This paper presents an inductorless cascaded H- bridge multilevel boost inverter for EV and HEV applications. Currently available power inverter systems for HEVs use a DC- DC boost converter to boost the battery voltage for a traditional 3-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky

Burak Ozpineci; Leon M. Tolbert; John N. Chiasson

2007-01-01

369

Large wind energy converter: Growian 3 MW  

NASA Technical Reports Server (NTRS)

The main features of the Growian wind energy converter are presented. Energy yield, environmental impact, and construction of the energy converter are discussed. Reliability of the windpowered system is assessed.

Koerber, F.; Thiele, H. A.

1979-01-01

370

A Framework for Historic Bridge Preservation  

E-print Network

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...

Puls, Eric Mark

2013-08-08

371

21. View of Clark Fork Vehicle Bridge facing west. Looking ...  

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

21. View of Clark Fork Vehicle Bridge facing west. Looking at bridge deck, guard rail, juncture of two bridge spans. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

372

33 CFR 118.70 - Lights on swing bridges.  

... 2014-07-01 2014-07-01 false Lights on swing bridges. 118.70 Section 118...BRIDGE LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges. Each swing...

2014-07-01

373

23 CFR 650.809 - Movable span bridges.  

...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...

2014-04-01

374

23 CFR 650.809 - Movable span bridges.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

375

23 CFR 650.809 - Movable span bridges.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

376

23 CFR 650.809 - Movable span bridges.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

377

23 CFR 650.809 - Movable span bridges.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

378

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

379

A study of the high frequency limitations of series resonant converters  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

380

A study of DC-DC converters with MCT's for arcjet power supplies  

NASA Technical Reports Server (NTRS)

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.

Stuart, Thomas A.

1994-01-01

381

A study of DC-DC converters with MCTs for arcjet power supplies  

NASA Astrophysics Data System (ADS)

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 metal oxide semiconductor controlled thyristors (MCT's). 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.

Stuart, Thomas A.; King, Roger J.; Masserant, Brian J.

1993-01-01

382

Bridges on the River Quad  

NSDL National Science Digital Library

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.

2012-08-30

383

The Bridge to Manufacturing Project  

ERIC Educational Resources Information Center

A grant project was designed to facilitate the transition of students from a community college adult education program into a community college credit-degree program in manufacturing. Key features of the program included a focus on identifying policy implications; bridging the separation between the adult education segment of the community college…

Puchner, Laurel; Taylor, Ann R.; Harris, Valorie K.; Marshall, Rick W.; Powell, Margaret

2010-01-01

384

to China: A Bridge Between  

E-print Network

From Yale to China: A Bridge Between Cultures Students often invoke the metaphor of a journey in China," she said. "Yale oered a vast array of resources to help me improve my language compe- tency program and myriad exchanges with China. The summer before her sophomore year at Yale, Jenna received

385

The Bridges of Social Change  

E-print Network

of Philadelphia to the Garden State of New Jersey. This majestic bridge models Cret's ability to incorporate was conceived and created for commuters between New Jersey and Philadelphia, he had the fore- sight to design, highlights SP2's interdisciplinary focus by featuring its work with city planning, veterinary studies

Sharp, Kim

386

A Changing Bridge for Changing Times: The History of the West Boston Bridge, 1793-1907  

Microsoft Academic Search

Master of Arts Thesis, June 2000: This thesis examines the construction in 1793 of the West Boston Bridge, the first bridge to span the Charles River between Boston and Cambridge, and its successors at the same location in 1854 and then 1907 (the Longfellow Bridge). It is a study of the impact of these bridges on the commercial development and

Dale H Freeman

2000-01-01

387

Light-off behavior of catalytic converters  

Microsoft Academic Search

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

P. S. Hagan; D. W. Schwendeman

1994-01-01

388

COMMUNITY ALERT INCIDENT: Catalytic Converter Thefts  

E-print Network

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

Rose, Michael R.

389

Compact HVDC converter station design considerations  

Microsoft Academic Search

In this paper, the possible means to reduce HVDC converter station land area requirements are shown. The split-up of real estate between the different kinds of equipment in present-day terminals is analysed. From this, a priority list for suitable action to be taken is deducted. Three concepts of converter valves suitable for compact converter stations are briefly discussed. By example

P. Lips

1976-01-01

390

Acoustics of automotive catalytic converter assemblies  

Microsoft Academic Search

In an automotive exhaust system, the purpose of the catalytic converter is to reduce pollutant emissions. However, catalytic converters also affect the engine and exhaust system breathing characteristics; they increase backpressure, affect exhaust system acoustic characteristics, and contribute to exhaust manifold tuning. Thus, radiated sound models should include catalytic converters since they can affect both the source characteristics and the

Nolan S. Dickey; Ahmet Selamet; Steve J. Parks; Kevin V. Tallio; Keith D. Miazgowicz; Paul M. Radavich

2003-01-01

391

Method for Controlling a Multilevel Cascade BTB System Using Bidirectional Isolated DC/DC Converters  

NASA Astrophysics Data System (ADS)

This paper discusses a 6.6-kV next-generation BTB system in which bidirectional isolated dc/dc converters are combined with modular multilevel cascade converters. The system consists of N converter cells cascaded in each phase at both front ends. Each converter cell consists of a bidirectional isolated dc/dc converter and two voltage-source H-bridge PWM converters. This circuit configuration can be adopted to significantly reduce harmonic voltages and currents because the voltage steps are extremely low. In a conventional power conversion system, bulky line-frequency transformers are employed. On the other hand, in the present system, light and compact high-frequency transformers are used for providing galvanic isolation. Thus, the overall physical size and weight are reduced. The authors design, construct, and test a single-phase 120-V, 3.3-kW downscaled model with N=3, in order to verify the feasibility and effectiveness. The downscaled model helps to develop an operable 6.6-kV system with focus on control and performance.

Kitada, Ryohei; Akagi, Hirofumi

392

Auxiliary resonant DC tank converter  

DOEpatents

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

Peng, Fang Z. (Knoxville, TN)

2000-01-01

393

Lightweight multiple output converter development  

NASA Technical Reports Server (NTRS)

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.

Kisch, J. J.; Martinelli, R. M.

1978-01-01

394

PROJECT BRIDGE JUNE-JULY 2013  

E-print Network

PROJECT BRIDGE JUNE-JULY 2013 Project Bridge is a newsletter of the Center for Disabilities Studies in June, July and early August. Some changes have been made to the format and layout of Project Bridge with Disabilities Through funding from the Delaware Division of Public Health Dental Program, Healthy Delawareans

Firestone, Jeremy

395

Evacuation research ............... 3 Bridge collapse course............ 3  

E-print Network

for research related to I-35W bridge collapse, share insight with media Two new research projects are under way in response to the August 1 collapse of the I-35W bridge in Minneapolis. Faculty in the Department of CivilInside · Evacuation research ............... 3 · Bridge collapse course............ 3 · Call

Minnesota, University of

396

Development of a bridge fault extractor tool  

E-print Network

...................................??............................................................. 50 VITA?????...????????????????????????. 55 vii LIST OF FIGURES Page Figure 1. Different bridge models... Page Table 1. Previous, present and future semiconductor technology roadmap......................... 2 Table 2: FedEx improvements (insertion ? only intralayer bridges).................................. 27 Table 3. FedEx improvements (bridging...

Bhat, Nandan D.

2005-02-17

397

Preservation Treatment for Wood Bridge Application  

Microsoft Academic Search

Timber can often be a cost-effective construction material for new bridges. The durability of the bridge greatly depends on proper attention to construction details and fabrication, as well as proper preservative treatment before, during, and after construction. Material repair and replacement costs for bridges are a considerable expense for highway agencies. To address these needs, the objectives of an investigation

Jake Bigelow; Stan Lebow; Carol A. Clausen; Lowell Greimann; Terry J. Wipf

2009-01-01

398

A Participatory Public Art Project: Community Bridge  

ERIC Educational Resources Information Center

This article introduces Community Bridge, a participatory public art project that brought together artists and residents to address aesthetic needs of an urban environment. The Community Bridge is an exemplary work of art by American artist William Cochran. In addition to creating a natural gathering place for residents of all ages, the bridge is…

Stephens, Pam

2005-01-01

399

Voltage control of modified series-connected HVDC bridges using GTO thyristor by-pass valves  

Microsoft Academic Search

Direct current (DC) links are finding increasing use throughout the world in the form of long distance transmission and a synchronous interconnections. The objective of this paper is to present a new method to control the HVDC converter by modified series-connected bridges with GTO thyristor by-pass valves to give more reduction in both harmonics generation and reactive volt–ampere absorption for

Hussein D. Al-Majali

1999-01-01

400

Equal load sharing modulation technique for series-connected H-bridge multilevel converters  

Microsoft Academic Search

A modulation scheme for multilevel inverters, which ensures equal loading of the power modules is presented. The scheme uses two-to-three transformation to calculate duty-cycles of each phase directly from the reference vector expressed in the Cartesian coordinate system. There is no need for trigonometric functions, which makes the applicability of the algorithm very effective in a DSP or an FPGA.

Ville Naumanen; Julius Luukko; Toni Itkonen; Olli Pyrhönen; Juha Pyrhönen

2008-01-01

401

Reduced Switching Frequency Active Harmonic Elimination for Multilevel Converters  

SciTech Connect

This paper presents a reduced switching-frequency active-harmonic-elimination method (RAHEM) to eliminate any number of specific order harmonics of multilevel converters. First, resultant theory is applied to transcendental equations to eliminate low-order harmonics and to determine switching angles for a fundamental frequency-switching scheme. Next, based on the number of harmonics to be eliminated, Newton climbing method is applied to transcendental equations to eliminate high-order harmonics and to determine switching angles for the fundamental frequency-switching scheme. Third, the magnitudes and phases of the residual lower order harmonics are computed, generated, and subtracted from the original voltage waveform to eliminate these low-order harmonics. Compared to the active-harmonic-elimination method (AHEM), which generates square waves to cancel high-order harmonics, RAHEM has lower switching frequency. The simulation results show that the method can effectively eliminate all the specific harmonics, and a low total harmonic distortion (THD) near sine wave is produced. An experimental 11-level H-bridge multilevel converter with a field-programmable gate-array controller is employed to experimentally validate the method. The experimental results show that RAHEM does effectively eliminate any number of specific harmonics, and the output voltage waveform has low switching frequency and low THD.

Du, Zhong [ORNL; Tolbert, Leon M [ORNL; Chiasson, John N [ORNL; Ozpineci, Burak [ORNL

2008-01-01

402

Performance analysis of LAN bridges and routers  

NASA Technical Reports Server (NTRS)

Bridges and routers are used to interconnect Local Area Networks (LANs). The performance of these devices is important since they can become bottlenecks in large multi-segment networks. Performance metrics and test methodology for bridges and routers were not standardized. Performance data reported by vendors is not applicable to the actual scenarios encountered in an operational network. However, vendor-provided data can be used to calibrate models of bridges and routers that, along with other models, yield performance data for a network. Several tools are available for modeling bridges and routers - Network II.5 was used. The results of the analysis of some bridges and routers are presented.

Hajare, Ankur R.

1991-01-01

403

Strengthening Bridges with Prestressed CFRP Strips  

NASA Astrophysics Data System (ADS)

Limitation of bridge's carrying bearing capacity due to aging and deterioration is a common problem faced by road administration and drivers. Rehabilitation of bridges including strengthening may be applied in order to maintain or upgrade existing bridge parameters. The case studies of strengthening of two small bridges with high modulus prestressed CFRP strips have been presented in the paper. The first one - reinforced concrete slab bridge - and the other - composite steel-concrete girder bridge - have been successfully upgraded with quite new technology. In both cases the additional CFRP reinforcement let increasing of bridge carrying capacity from 15 till 40 metric tons. The CFRP strip prestressing system named Neoxe Prestressing System (NPS), developed by multi-disciplinary team and tested at full scale in Rzeszow University of Technology, has been also described in the paper.

Siwowski, Tomasz; ?ó?towski, Piotr

2012-06-01

404

Evaluation of a Modified ADC-Based Thermometry Bridge  

NASA Astrophysics Data System (ADS)

This article presents the modification and testing of an ADC-based thermometry bridge. The instrument under investigation is an Anton Paar MKT 50 Millikelvin Thermometer (developed at the IFE, TU-Graz) based on a precision analog-to-digital converter (ADC). During preliminary testing, it was found that the MKT 50 performs better than its declared uncertainty (1 mK equal to 1 ppm when using a 100 ? PRT) and is comparable to thermometry resistance ratio bridges typically used in secondary thermometry laboratories (with typical uncertainties from 0.1 mK to 1 mK). The modifications to the original bridge were undertaken by the development team of the MKT 50 at the Graz University of Technology, Austria. Measurements and evaluation of the modified instruments were performed at the MIRS/UL-FE/LMK. For the MKT 50 to be used in thermometry laboratories as a reference unit, measuring parameters of the instrument had to be changed. During the first modification, the upper limit of the instrument range was decreased from 400 ? to 133 ?, this is a preferred range for standard platinum resistance thermometers (SPRTs). This also meant an increase in the measuring current from 0.5 mA to the more frequently used 1 mA. A modification of the programmable ADC control unit increased the resolution from 24 bit to 27 bit. By adding a switch, the use of an external standard resistor was enabled. After this stage of the modification, the first tests on the instrument were performed. The second stage was aimed at the removal of noise sources. The instrument was prepared in such a way that it only used two input channels, one connected to the SPRT and the other to the standard resistor. Also, the components of the ADC were upgraded to further reduce noise. The elimination of one input channel sped up measurements, making the PC software capable of taking several readings in a shorter time period. All tests were performed in laboratory conditions, where precision AC and DC resistance ratio bridges are typically used. The non-linearity was assessed by the use of an automated resistance bridge calibrator (RBC, Model RBC100), while the noise value was determined both from the standard deviation of RBC measurements as well as from comparison measurements of two standard resistors. All tests were repeated several times to assure confidence in the results. With its lowered range of 133 ? and an increased resolution of 27 bit, the instrument non-linearity, its value below 2 ??, was comparable to primary resistance ratio bridges such as the ASL F900 or MI 6015T. However, the noise of the instrument remained relatively high at 4 ??. Since the modified MKT-50 is a much faster instrument than AC and DC bridges, averaging was used for true comparison. Measurements done with the modified MKT 50 were also averaged every 15 s (the time a classic resistance ratio bridge takes for one measurement). When measurements with the MKT-50 were averaged, the noise of measurements would be comparable to primary resistance ratio bridges.

Podgornik, T.; Batagelj, V.; Winkler, G.; Hartl, H.; Drnovsek, J.

2011-12-01

405

New oxa-bridged macrocycles.  

PubMed

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

Panten, Johannes; Surburg, Horst; Hölscher, Bernd

2008-06-01

406

Wood stove having catalytic converter  

SciTech Connect

A wood burning stove is formed with double front and rear side walls of heat conductive metal spaced apart by heat conductive spacer fins and providing air passageways by which room air is heated by conduction from the walls which are heated by the burning of wood deposited on a firebox floor supported in heat conducting relationship with the inner side walls. A catalytic converter is disposed over the fire area in the upper portion of the stove, and is arranged to receive preheated fresh secondary air which mixes with hot, incompletely combusted compounds from the fire and, in the presence of the catalyst, induces a secondary combustion of the substances. This mixture is channeled into a heat extraction chamber where the secondary combustion is completed and the resultant heat is transferred to the metal body of the stove. An exhaust passageway is provided for releasing the products of complete combustion into the atmosphere.

Willson, A.C.

1982-12-14

407

Thermionic converter emitter support arrangement  

DOEpatents

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.

Allen, Daniel T. (La Jolla, CA)

1990-01-01

408

Thermionic converter emitter support arrangement  

DOEpatents

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.

Allen, Daniel T. (La Jolla, CA)

1990-01-01

409

Dynamical Bridges: The Electromagnetic Case  

NASA Astrophysics Data System (ADS)

We present the main line of the Dynamical Bridge method applied to electromagnetic (EM) fields. In this framework, we show the equivalence between the Born- Infeld theory written in a given curved space to the Maxwell's one written in the flat space. In the limit of weak EM fields, we obtain a geometrical contribution to the anomalous magnetic moment of the leptons and, finally, we compare it with experimental data.

Bittencourt, Eduardo

2014-12-01

410

Halliburton Composite Bridge Plug Assembly  

SciTech Connect

The overall objectives of this CRADA were to assist Halliburton in analyzing a composite bridge plug and to determine why their original design was failing in the field. In Phase 1, finite element analyses were done on the original composite slip design and several alternative designs. The composite slip was the component in the bridge plug that was failing. The finite element code ABAQUS was used for these calculations and I-DEAS was used as the pre- and post-processor in the analyses. Several different designs and materials were analyzed and recommendations were made towards improving the design. In Phase 2, the objective was to develop finite element models that would accurately represent the deformations in the entire all-composite 4-1/2' diameter bridge plug assembly. The finite element code LS-DYNA was used and the results from this effort were intended to expand Halliburton's composite design and analysis capabilities with regard to developing future composite components for downhole tools. In addition to the finite element modeling, this effort involved the utilization of micromechanics to determine the necessary composite material properties that were needed as input for finite element codes.

Starbuck, J.M.; Luttrell, C.R.; Aramayo, G.

2005-01-15

411

Scour assessment at bridges from Flag Point to Million Dollar Bridge, Copper River Highway, Alaska  

USGS Publications Warehouse

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.

Brabets, T.P.

1994-01-01

412

Salt Bridges: Geometrically Specific, Designable Interactions  

PubMed Central

Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, cooperativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction upon formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but at close distances there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms. PMID:21287621

Donald, Jason E.; Kulp, Daniel W.; DeGrado, William F.

2010-01-01

413

Radiation-Tolerant DC-DC Converters  

NASA Technical Reports Server (NTRS)

A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

2012-01-01

414

Performance of Power Converters at Cryogenic Temperatures  

NASA Technical Reports Server (NTRS)

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.

Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

2001-01-01

415

Development of a Modular Power Converter  

NASA Astrophysics Data System (ADS)

This report describes the most important details of elaboration of a versatile power module that can be utilized as a part of various converters. Two or more modules connected together can form a frequency converter or multilevel converter or 3-phase inverter/rectifier etc. Initially the module was developed for fast prototyping of uninterruptible power supplies and energy systems with alternative energy sources. The module can be used also as a basis for laboratory equipment of the power electronics course.

Stepanov, A.; Biesenieks, L.; Sokolovs, A.; Galkin, I.

2009-01-01

416

Low Frequency Characterization of PWM Converters  

Microsoft Academic Search

Low frequency components of states or outputs in pulse-width modulation (PWM) dc and ac converters can be characterized by differential equations called describing state-space equations. These equations are derived by inspection of converter topology and use of switching functions and duty ratios. Their steady-state and small-signal dynamic solutions show how energy-storage elements in a converter\\/load system shape the frequency response

Khai D. T. Ngo

1986-01-01

417

Modal Identification of Tsing MA Bridge by Using Improved Eigensystem Realization Algorithm  

NASA Astrophysics Data System (ADS)

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.

QIN, Q.; LI, H. B.; QIAN, L. Z.; LAU, C.-K.

2001-10-01

418

Vacuum-insulated catalytic converter  

DOEpatents

A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

Benson, David K. (Golden, CO)

2001-01-01

419

Myocardial bridges: morphological and functional aspects  

Microsoft Academic Search

OBJECTIVE--To assess the arrangement of myocardial bridges. DESIGN--A necropsy study of 90 consecutive hearts (56 male, 34 female). RESULTS--Myocardial bridges, either single or multiple, were seen in 50 (55.6%) of the 90 hearts. The left anterior descending artery was the most commonly affected artery. Thirty five of the 50 hearts which contained in total 41 muscle bridges were dissected further

A G Ferreira; S E Trotter; B König; L V Décourt; K Fox; E G Olsen

1991-01-01

420

Overweight permit formulas for simply supported bridges  

E-print Network

older bridge designs. Seelye (1957) provided design specifications for span lengths up to 80 ft. for these two types of bridges. The two typical bridge cross sections from Seelye (1957) are shown in Figs. 6 and 7. 1/2' 91 5 3" 2I2ll 10e 12. 0s... of 14. 5 inches from Table 3 results in a cross sectional area of 7. 0 ft . With a concrete density of 0. 15k/ft3 the distributed dead load is 1. 05k/ft. as seen in Table 5. The calculations for a steel stringer bridge would be similar except...

Mattox, Michael Joseph

2012-06-07

421

Buddha and the bridging relations.  

PubMed

The chapter reviews a classical Indian model of consciousness found in the Abhidhamma, a collection of seven treatises in the Pali Canon Tipitaka. The model was based on observations made during advanced vipassana practice, a first-person method taught by the Buddha. The climax of the model consists in the elucidation of 24 'Bridging Relations' causally linking the stream of consciousness, its contents and associated physical events. Review of such a model based on a specialized first-person technique could prove to be a resource of useful ideas providing directions for further research. PMID:18166400

Banerjee, Rahul

2008-01-01

422

Predicted and Measured Response of an Integral Abutment Bridge  

Microsoft Academic Search

This project examined several uncertainties of integral abutment bridge design and analysis through field-monitoring of an integral abutment bridge and three levels of numerical modeling. Field monitoring data from a Pennsylvania bridge site was used to refine the numerical models that were then used to predict the integral abutment bridge behavior of other Pennsylvania bridges of similar construction. The instrumented

Jolene L. Fennema; Jeffrey A. Laman; Daniel G. Linzell

2005-01-01

423

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

424

Novel multi-element resonant converters for front-end dc\\/dc converters  

Microsoft Academic Search

This paper proposes novel multi-element resonant converters for front-end dc\\/dc converters. The superior performance of the proposed resonant converters is to provide inherent current protection and very low circulating energy. With the optimized design, the proposed resonant converters can operate under short output circuit. Based on the third order harmonic injection, the circulating energy of the resonant tank can be

Dianbo Fu; Fred C. Lee; Ya Liu; Ming Xu

2008-01-01

425

A direct AC\\/AC converter based on current-source converter modules  

Microsoft Academic Search

The research on direct AC\\/AC conversion in the past twenty years has been following two major directions: improving the performance of the original nine-bidirectional-switch matrix converter topology; and using converter topologies composed of unidirectional switches only. In this paper, a direct AC\\/AC converter topology based on current-source converter modules is proposed. It is shown, through analysis and simulation, that the

Mehrdad Kazerani

2003-01-01

426

Celilo Converter Station mercury arc valve replacement  

Microsoft Academic Search

The Pacific HVDC Intertie (PDCI) is the most complicated HVDC Scheme in the world. Decisions about changing the PDCI are further complicated by a complex ownership arrangement. The Intertie has the a capacity of 3100 MW and runs from the Celilo Converter Station in The Dalles, Oregon to the Sylmar Converter Station in Sylmar, California. After an earthquake damaged the

Wayne Litzenberger

2002-01-01

427

The auxiliary resonant commutated pole converter  

Microsoft Academic Search

The auxiliary resonant commutated pole (ARCP), a new power converter topology that fully achieves soft switching without increasing primary device voltage or current ratings, is discussed. The ARCP converter is capable of true pulse-width modulation (PWM) control of each phase. The power circuit relies on the addition of an auxiliary triggered resonant commutation circuit or snubber to commutate the inductive

R. W. De Doncker; J. P. Lyons

1990-01-01

428

RF digital-to-analog converter  

DOEpatents

A digital-to-analog converter is disclosed for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration. 18 figs.

Conway, P.H.; Yu, D.U.L.

1995-02-28

429

RF digital-to-analog converter  

DOEpatents

A digital-to analogue converter for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration.

Conway, Patrick H. (Rancho Palos Verdes, CA); Yu, David U. L. (Rancho Palos Verdes, CA)

1995-01-01

430

Directivity of parametric converters with biharmonic pumping  

Microsoft Academic Search

The conditions of stable amplification and ideal directivity of amplification are obtained for different types of three-frequency parametric converters with biharmonic pumping. The equivalent circuit of the converter incorporates a parametric diode whose elastance varies time-dependently under the action of voltages from two pumping sources and an oscillatory system containing resonant chains for three different working frequencies. A system of

Iu. K. Tarabrin

1976-01-01

431

Efficient polarization converter for projection displays  

E-print Network

Efficient polarization converter for projection displays W. C. Yip, H. C. Huang, and H. S. Kwok In the waveguiding limit, a twisted nematic liquid crystal cell behaves as an achromatic polarization rotator. We propose and demonstrate the application of such a polarization rotator to convert unpolar- ized light

432

Firing angle optimisation for chain cell converters  

Microsoft Academic Search

Firing angles for chain cell multi-level converters can be optimised to reduce waveform distortion. Optimisation techniques have previously been developed that calculate the required firing angles, but these techniques fall short of accurate optimisation due to over-simplification of the problem. Established optimisation routines often only work on a subset of possible converter modes, hence optimal solutions are not produced for

D. W. Sandells; T. C. Green

2001-01-01

433

Optimal design methodology for LLC resonant converter  

Microsoft Academic Search

Although LLC resonant converter can achieve wide operation range with high efficiency, lack of design methodology makes it difficult to be implemented. In this paper, based on the theoretical analysis on the operation principles during normal condition and holdup time, the relationship between converter efficiency and operation range with different circuit parameters has be revealed. An optimal design methodology has

Bing Lu; Wenduo Liu; Yan Liang; Fred C. Lee; Jacobus D. van Wyk

2006-01-01

434

Multilevel converters for 10 MW Wind Turbines  

Microsoft Academic Search

Several promising multi-level converter configurations for 10 MW Wind Turbines both with direct drive and one-stage gear box drive using Permanent Magnet Synchronous Generator (PMSG) are proposed, designed and compared. Reliability is a crucial indicator for large scale wind power converters, therefore the evaluations are mainly focused on the power device thermal performances, which are closely related to the life

Ke Ma; Frede Blaabjerg

2011-01-01

435

Time interleaved counter analog to digital converters   

E-print Network

The work explores extending time interleaving in A/D converters, by applying a high-level of parallelism to one of the slowest and simplest types of data-converters, the counter ADC. The motivation for the work is to ...

Danesh, Seyed Amir Ali

2011-11-22

436

Component technology for Stirling power converters  

Microsoft Academic Search

NASA Lewis Research Center has organized a component technology program as part of the efforts to develop Stirling converter technology for space power applications. The Stirling Space Power Program is part of the NASA High Capacity Power Project of the Civil Space Technology Initiative (CSTI). NASA Lewis is also providing technical management for the DOE\\/Sandia program to develop Stirling converters

Lanny G. Thieme

1991-01-01

437

Pulse doubling in zigzag-connected autotransformer-based 12-pulse ac-dc converter for power quality improvement  

NASA Astrophysics Data System (ADS)

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.

Abdollahi, Rohollah

2012-12-01

438

A Changing Bridge for Changing Times: The History of the West Boston Bridge, 1793-1907  

Microsoft Academic Search

This thesis examines the building of the West Boston Bridge in 1793, which was the first bridge to cross the Charles River between Cambridge and Boston, as well as the building of its successors at the same location in 1854 and 1907. It is a study of how these bridges brought change to both Boston and Cambridge which resulted not

Dale H Freeman

2000-01-01

439

rBridge: User Reputation based Tor Bridge Distribution with Privacy Preservation  

E-print Network

rBridge: User Reputation based Tor Bridge Distribution with Privacy Preservation Qiyan Wang Department of Computer Science University of Minnesota hopper@cs.umn.edu Abstract Tor is one of the most censorship. A key challenge to the Tor circumvention system is to distribute bridges to a large number

Minnesota, University of

440

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

441

Evaluations of uranium-nitride fueled converters.  

NASA Technical Reports Server (NTRS)

Evaluation of two uranium-nitride (UN) fueled converters was initiated at the Jet Propulsion Laboratory to investigate the effect of fuel on the converter performance while being operated out-of-core. The initial tests were performed with the dynamic data acquisition system that was developed at the Laboratory. Parametric tests of these converters were to obtain: (1) static volt-ampere curves, (2) dynamic volt-ampere curves, and (3) the electrode work functions. The power outputs were 9.3 W/sq cm for the rhenium converter and 3.8 W/sq cm for the tungsten converter at 0.6 V when the emitter surface temperature was 2000 K, according to the static volt-ampere curves.

Shimada, K.; Cassell, P. L.

1971-01-01

442

Modelling, analyses and design of switching converters  

NASA Technical Reports Server (NTRS)

A state-space averaging method for modelling switching dc-to-dc converters for both continuous and discontinuous conduction mode is developed. In each case the starting point is the unified state-space representation, and the end result is a complete linear circuit model, for each conduction mode, which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small-signal). While the method is generally applicable to any switching converter, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model. The insights that emerge from the general state-space modelling approach lead to the design of new converter topologies through the study of generic properties of the cascade connection of basic buck and boost converters.

Cuk, S. M.; Middlebrook, R. D.

1978-01-01

443

Bridge coupled drift tube linacs  

NASA Astrophysics Data System (ADS)

Modern linac designs for treating radioactive waste achieve high proton currents through funneling at low energy, typically around 20 MeV. The resulting switch to a high-frequency accelerating structure poses severe performance and fabrication difficulties below 100 MeV. Above 100 MeV, proven coupled-cavity linacs (CCLs) are available. However, at 20 MeV one must choose between a high-frequency drift-tube linac (DTL) or a coupled-cavity linac with very short cells. Potential radiation damage from the CW beam, excessive RF power losses, multipactoring, and fabricability all enter into this decision. At Los Alamos, we have developed designs for a bridge-coupled DTL (BCDTL) that, like a CCL, uses lattice focusing elements and bridge couplers, but that unlike a CCL, accelerates the beam in simple, short, large aperture DTL modules with no internal quadrupole focusing. Thus, the BCDTL consumes less power than the CCL linac without degrading beam performance and is simpler and cheaper to fabricate in the 20 to 100 MeV range.

Liska, D.; Smith, P.; Carlisle, L.; Larkin, T.

1993-06-01

444

Bridges to sustainable tropical health  

PubMed Central

Ensuring sustainable health in the tropics will require bridge building between communities that currently have a limited track record of interaction. It will also require new organizational innovation if much of the negative health consequences of large-scale economic development projects are to be equitably mitigated, if not prevented. We focus attention on three specific contexts: (i) forging linkages between the engineering and health communities to implement clean water and sanitation on a broad scale to prevent reworming, after the current deworming-only programs, of people by diverse intestinal parasites; (ii) building integrated human and animal disease surveillance infrastructure and technical capacity in tropical countries on the reporting and scientific evidence requirements of the sanitary and phytosanitary agreement under the World Trade Organization; and (iii) developing an independent and equitable organizational structure for health impact assessments as well as monitoring and mitigation of health consequences of economic development projects. Effective global disease surveillance and timely early warning of new outbreaks will require a far closer integration of veterinary and human medicine than heretofore. Many of the necessary surveillance components exist within separate animal- and human-oriented organizations. The challenge is to build the necessary bridges between them. PMID:17913894

Singer, Burton H.; de Castro, Marcia Caldas

2007-01-01

445

Salt-bridge energetics in halophilic proteins.  

PubMed

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

Nayek, Arnab; Sen Gupta, Parth Sarthi; Banerjee, Shyamashree; Mondal, Buddhadev; Bandyopadhyay, Amal K

2014-01-01

446

Boost matrix converters in clean energy systems  

NASA Astrophysics Data System (ADS)

This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.

Karaman, Ekrem

447

Fault analysis and special tests of thyristor for RFX ac/dc converters  

SciTech Connect

In the RFX nuclear fusion experiment twenty ac/dc converter units, for a total installed power of over 400 MVA, are used to feed the machine magnets. Due to the special characteristics of the load, and in particular to the expected fault conditions, the converter bridges must withstand a high number (approximately 2,000) of severe overloads during the life of the machine; in particular the thyristors must carry a current two or three times larger than the nominal current without any damage. In addition the thyristors must not explode even in the case of a slightly higher surge current than the previous one, when the fuse does not blow quickly. As the manufacturer's data did not cover the thyristor performance under these specific requirements, new tests on the thyristors had to be carried out and the results are discussed in the paper.

Piovan, R.; Gaio, E. (Instituto Gas Ionizzati, Associazione EURATOM-ENEA-CNR (IT)); Maschio, A. (Universita di Trento, Dipartimento di Ingegneria, Mesiano TN (IT)); Tenconi, S. (Ansaldo Ricerche Milano (IT))

1990-01-01

448

Advanced Energy Conversion System Using Sinusoidal Voltage Tracking Buck-Boost Converter Cascaded Polarity Changing Inverter  

NASA Astrophysics Data System (ADS)

This paper presents an advanced power converter employs a sinusoidal voltage absolute value tracking buck-boost DC-DC converter in the first power processing stage and a polarity changing full-bridge inverter in the second stage. The proposed power conversion system has the capability of delivering sinusoidal output and input current with unity power factor and good output voltage regulation. Consequently, the complete voltage regulator system, which is mainly suitable for new energy generation systems as well as energy storage systems, can be constructed compactly and inexpensively without DC link electrolytic capacitor. Also, the paper presents an auxiliary passive resonant circuit for soft switching operation. Simulation results using PSIM software are presented to verify the operation principles and feasibility of the proposed power conversion system.

Ahmed, Nabil A.

2011-06-01

449

The 25 kW resonant dc/dc power converter  

NASA Technical Reports Server (NTRS)

The feasibility of processing 25-kW of power with a single, transistorized, series resonant converter stage was demonstrated by the successful design, development, fabrication, and testing of such a device which employs four Westinghouse D7ST transistors in a full-bridge configuration and operates from a 250-to-350 Vdc input bus. The unit has an overall worst-case efficiency of 93.5% at its full rated output of 1000 V and 25 A dc. A solid-state dc input circuit breaker and output-transient-current limiters are included in and integrated into the design. Full circuit details of the converter are presented along with the test data.

Robson, R. R.

1983-01-01

450

21 CFR 872.3770 - Temporary crown and bridge resin.  

... false Temporary crown and bridge resin. 872.3770 Section...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device...

2014-04-01

451

21 CFR 872.3770 - Temporary crown and bridge resin.  

Code of Federal Regulations, 2011 CFR

... false Temporary crown and bridge resin. 872.3770 Section...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device...

2011-04-01

452

21 CFR 872.3770 - Temporary crown and bridge resin.  

Code of Federal Regulations, 2013 CFR

... false Temporary crown and bridge resin. 872.3770 Section...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device...

2013-04-01

453

21 CFR 872.3770 - Temporary crown and bridge resin.  

Code of Federal Regulations, 2012 CFR

... false Temporary crown and bridge resin. 872.3770 Section...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device...

2012-04-01

454

Plastic Hinging Behavior of Reinforced Concrete Bridge Columns  

E-print Network

The location of inelastic deformations in reinforced concrete bridge columns has been examined to simulate the nonlinear response of bridge columns and estimate the ultimate displacement capacity. In bridge columns, these nonlinear deformations...

Firat Alemdar, Zeynep

2010-04-27

455

OUTERBRIDGE CROSSING BRIDGE LINED UP WITH MANHATTAN SKYLINE IN MIDDLE ...  

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

OUTERBRIDGE CROSSING BRIDGE LINED UP WITH MANHATTAN SKYLINE IN MIDDLE OF HORIZON, VERRAZANO NARROWS BRIDGE TO THE RIGHT - Outerbridge Crossing Bridge, Spanning Arthur Kill from New Jersey to Staten Island, Staten Island (subdivision), Richmond County, NY

456

49 CFR 237.101 - Scheduling of bridge inspections.  

Code of Federal Regulations, 2011 CFR

...inspection for each bridge in railroad service at least once...management program when a railroad bridge engineer determines...flood, fire, earthquake, derailment or vehicular or vessel impact. (d) Any railroad bridge that has not...

2011-10-01

457

49 CFR 237.101 - Scheduling of bridge inspections.  

Code of Federal Regulations, 2012 CFR

...inspection for each bridge in railroad service at least once...management program when a railroad bridge engineer determines...flood, fire, earthquake, derailment or vehicular or vessel impact. (d) Any railroad bridge that has not...

2012-10-01

458

49 CFR 237.101 - Scheduling of bridge inspections.  

Code of Federal Regulations, 2013 CFR

...inspection for each bridge in railroad service at least once...management program when a railroad bridge engineer determines...flood, fire, earthquake, derailment or vehicular or vessel impact. (d) Any railroad bridge that has not...

2013-10-01

459

49 CFR 237.101 - Scheduling of bridge inspections.  

Code of Federal Regulations, 2010 CFR

...inspection for each bridge in railroad service at least once...management program when a railroad bridge engineer determines...flood, fire, earthquake, derailment or vehicular or vessel impact. (d) Any railroad bridge that has not...

2010-10-01

460

29 CFR 1917.124 - Dockboards (car and bridge plates).  

... 2014-07-01 false Dockboards (car and bridge plates). 1917.124 Section...Facilities § 1917.124 Dockboards (car and bridge plates). (a) General... (b) [Reserved] (c) Dockboards (car and bridge plates). (1)...

2014-07-01

461

Accurate resistive bridge fault modeling, simulation, and test generation  

E-print Network

Resistive bridging faults in CMOS combinational circuits are studied in this work. Bridging faults are modeled using HSPICE circuit simulation of the various types of bridging faults that can occur in CMOS combinational circuits. The results...

Sar-Dessai, Vijay Ramesh

2012-06-07

462

21. c, 1915 Historic plan, standard 2 beam girder bridge. ...  

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

21. c, 1915 Historic plan, standard 2 beam girder bridge. United Construction Company, Albany, New York. Generic plan typical of Prescott Bridge. Source: New Hampshire Department of Transportation - Prescott Bridge, Spanning Lamprey River on Prescott Road, Raymond, Rockingham County, NH

463

2. VIEW FROM OPPOSITE SOUTHEAST CORNER OF BRIDGE, LOOKING NORTH ...  

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

2. VIEW FROM OPPOSITE SOUTHEAST CORNER OF BRIDGE, LOOKING NORTH ALONG EASTERN ELEVATION. 14TH STREET BRIDGE AT RIGHT. - Tidal Reservoir, Outlet, Spanning Tidal Reservoir Outlet at Fourteenth Street Bridge, Washington, District of Columbia, DC

464

1. Elkmont vehicle bridge at Elkmont Campground, galvanized corrugated arch. ...  

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

1. Elkmont vehicle bridge at Elkmont Campground, galvanized corrugated arch. - Great Smoky Mountains National Park Roads & Bridges, Elkmont Vehicle Bridge, Spanning Little River at Elkmont Campground, Gatlinburg, Sevier County, TN

465

1. View of Clark Fork Vehicle Bridge facing west. Panorama ...  

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

1. View of Clark Fork Vehicle Bridge facing west. Panorama showing the entire span of bridge from north shore of the Clark Fork River. - Clark Fork Vehicle Bridge, Spanning Clark Fork River, serves Highway 200, Clark Fork, Bonner County, ID

466

1. AERIAL VIEW LOOKING SOUTHWEST (OLD HARVARD STREET BRIDGE AT ...  

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

1. AERIAL VIEW LOOKING SOUTHWEST (OLD HARVARD STREET BRIDGE AT LEFT, NEW BRIDGE AT RIGHT) - Old Harvard Street Bridge, Spanning Rock Creek at National Zoological Park, Washington, District of Columbia, DC

467

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

468

11. Standing on westerly fender at edge of bridge looking ...  

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

11. Standing on westerly fender at edge of bridge looking easterly, showing horizontal beams for deck and cross beams (reflection of steel grating on deck). Also shows bridge guardrail. - Colusa Bridge, Spanning Sacramento River, Colusa, Colusa County, CA

469

29. Historic photographer, photographer unknown, c. 1944. VIEW OF BRIDGE, ...  

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

29. Historic photographer, photographer unknown, c. 1944. VIEW OF BRIDGE, LOOKING EAST FROM TOP OF WEST TOWER. SHEEP CROSSING BRIDGE. NOTE SWAY CABLES. - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

470

23 CFR 650.705 - Application for discretionary bridge funds.  

Code of Federal Regulations, 2010 CFR

...ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge...is responsible for submitting such data as required for candidate bridges. Data requested will include structure number, funds needed by fiscal...

2010-04-01

471

2. Contextual view of bridge in setting, from northwest end ...  

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

2. Contextual view of bridge in setting, from northwest end of bridge, view to south-southeast with Rawson Road in foreground. - Red Bank Creek Bridge, Spanning Red Bank Creek at Rawson Road, Red Bluff, Tehama County, CA

472

1. Contextual view of bridge in setting, from downstream, view ...  

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

1. Contextual view of bridge in setting, from downstream, view to southwest along Port Kenyon Road. South end of bridge at left. - Salt River Bridge, Spanning Salt River at Dillon Road, Ferndale, Humboldt County, CA

473

2. Contextual view of bridge in setting, from north end ...  

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

2. Contextual view of bridge in setting, from north end of bridge, view to north along Dillon Road. Former Valley Flower Creamery at right center. - Salt River Bridge, Spanning Salt River at Dillon Road, Ferndale, Humboldt County, CA

474

33 CFR 118.80 - Lights on bascule bridges.  

... 2014-07-01 2014-07-01 false Lights on bascule bridges. 118.80 Section 118...BRIDGE LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of every bascule...

2014-07-01

475

3. GENERAL VIEW LOOKING WEST, SHOWING LIFT BRIDGE. COUNTER WEIGHTS ...  

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

3. GENERAL VIEW LOOKING WEST, SHOWING LIFT BRIDGE. COUNTER WEIGHTS ARE LARGE SQUARES VISIBLE ABOVE BRIDGE. - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

476

GENERAL VIEW LOOKING WEST SHOWING LIFT BRIDGE. COUNTER WEIGHTS ARE ...  

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

GENERAL VIEW LOOKING WEST SHOWING LIFT BRIDGE. COUNTER WEIGHTS ARE LARGE SQUARES VISIBLE ABOVE BRIDGE - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

477

23 CFR 650.705 - Application for discretionary bridge funds.  

...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...

2014-04-01

478

23 CFR 650.705 - Application for discretionary bridge funds.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

479

23 CFR 650.807 - Bridges requiring a USCG permit.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

480

23 CFR 650.705 - Application for discretionary bridge funds.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

481

23 CFR 650.807 - Bridges requiring a USCG permit.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

482

23 CFR 650.705 - Application for discretionary bridge funds.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

483

23 CFR 650.807 - Bridges requiring a USCG permit.  

...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...

2014-04-01

484

33 CFR 118.140 - Painting bridge piers.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Painting bridge piers. 118.140 Section 118.140 ...SIGNALS § 118.140 Painting bridge piers. The District Commander may require painting the sides of bridge channel piers below the superstructure facing...

2011-07-01

485

33 CFR 118.140 - Painting bridge piers.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Painting bridge piers. 118.140 Section 118.140 ...SIGNALS § 118.140 Painting bridge piers. The District Commander may require painting the sides of bridge channel piers below the superstructure facing...

2010-07-01

486

3. VIEW EAST TOWARD STAMFORD ANCHOR BRIDGE #374 OF CIRCUIT ...  

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

3. VIEW EAST TOWARD STAMFORD ANCHOR BRIDGE #374 OF CIRCUIT BREAKER INSTALLATION ON CROSS BEAM OF BRIDGE. - New York, New Haven & Hartford Railroad, Bridge-Type Circuit Breakers, Long Island shoreline between Stamford & New Haven, Cos Cob, Fairfield County, CT

487

2. VIEW EAST TOWARD DARIEN ANCHOR BRIDGE #465 OF CIRCUIT ...  

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

2. VIEW EAST TOWARD DARIEN ANCHOR BRIDGE #465 OF CIRCUIT BREAKER INSTALLATION ON CROSS BEAM OF BRIDGE. - New York, New Haven & Hartford Railroad, Bridge-Type Circuit Breakers, Long Island shoreline between Stamford & New Haven, Cos Cob, Fairfield County, CT

488

2. VIEW EAST, GENERAL VIEW OF BRIDGE WITHIN SETTING, APPROACH ...  

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

2. VIEW EAST, GENERAL VIEW OF BRIDGE WITHIN SETTING, APPROACH SPANS ON RIGHT, PEDESTRIAN BRIDGE FOR HIKING TRAIL ON LEFT - Bridge No. 1132, Route 80, spanning Hammonasset River, Madison, New Haven County, CT

489

5. View showing Crooked River High Bridge in background and ...  

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

5. View showing Crooked River High Bridge in background and Ralph Modjeski railroad bridge in foreground - Crooked River High Bridge, Spanning Crooked River Gorge at Dalles-California Highway, Terrebonne, Deschutes County, OR

490

21 CFR 872.3770 - Temporary crown and bridge resin.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Temporary crown and bridge resin. 872.3770 Section 872.3770 Food...872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a...

2010-04-01

491

6. EARLY MORNING VIEW OF BOTH JOSO HIGH BRIDGE (UNION ...  

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

6. EARLY MORNING VIEW OF BOTH JOSO HIGH BRIDGE (UNION PACIFIC RAILROAD) IN BACKGROUND AND LYONS FERRY BRIDGE IN THE FOREGROUND - Snake River Bridge at Lyons' Ferry, State Route 261 spanning Snake River, Starbuck, Columbia County, WA

492

A long range full bandwidth Ethernet bridge  

SciTech Connect

An Ethernet Bridge has been built which has both a range which exceeds 39 kilometers and a full bandwidth of 10 Mbaud. The bridge is transparent to all Ethernet packets and is suitable for distant system control, distant high speed data collection and for all normal Ethernet use.

Thompson, M.A.; Lackey, J.L.; Nissen, K.H.; Thielman, D.J.; Hiulian, Z. (Physical Sciences Lab., Univ. of Wisconsin - Madison, 3725 Schneider Dr., Stoughton, WI (US))

1988-02-01

493

Build and Test a Paper Bridge  

NSDL National Science Digital Library

In this hands-on activity, learners make a bridge out of a folded piece of paper and two blocks. Then they test their structure by stacking coins (and other things) on it, discovering how much weight the bridge can support before it collapses. This activity explores engineering, technology, architecture, weight, compression, tension, and balance.

2012-06-26

494

Teaching Elements and Principles of Bridge Design  

ERIC Educational Resources Information Center

Bridge construction is a popular classroom activity. However, the basic principles of tension, compression, and counterbalance are not always clearly represented and defined. The common materials used to construct model bridges, such as straws, toothpicks, Legos[TM], and building blocks, are often too flexible or stationary to demonstrate the…

Beck, Charles

2005-01-01

495

Active aerodynamic stabilisation of long suspension bridges  

Microsoft Academic Search

The paper describes the addition of actively controlled aerodynamic appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suspension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to make use of control analysis and design techniques, a linear model of the structural and

Henrik Ditlev Nissen; Paul Haase Sørensen; Ole Jannerup

2004-01-01

496

The Higgs Bridge Roland E. Allen  

E-print Network

1 The Higgs Bridge Roland E. Allen The discovery of a new kind of particle is announced. It is the long-sought Higgs boson! Credit: CERN [or more precisely, a Higgs boson] #12;The tutorial article that this talk is based on: Roland E. Allen, "The Higgs bridge", Physica Scripta 89

Allen, Roland E.

497

A Novel Inductor-less DC-AC Cascaded H-bridge Multilevel Boost Inverter for Electric\\/Hybrid Electric Vehicle Applications  

Microsoft Academic Search

This paper presents an inductorless cascaded H- bridge multilevel boost inverter for EV and HEV applications. Currently available power inverter systems for HEVs use a DC- DC boost converter to boost the battery voltage for a traditional 3-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky

Zhong Du; Burak Ozpineci; Leon M Tolbert; John N Chiasson

2007-01-01

498

Acoustics of automotive catalytic converter assemblies  

NASA Astrophysics Data System (ADS)

In an automotive exhaust system, the purpose of the catalytic converter is to reduce pollutant emissions. However, catalytic converters also affect the engine and exhaust system breathing characteristics; they increase backpressure, affect exhaust system acoustic characteristics, and contribute to exhaust manifold tuning. Thus, radiated sound models should include catalytic converters since they can affect both the source characteristics and the exhaust system acoustic behavior. A typical catalytic converter assembly employs a ceramic substrate to carry the catalytically active noble metals. The substrate has numerous parallel tubes and is mounted in a housing with swelling mat or wire mesh around its periphery. Seals at the ends of the substrate can be used to help force flow through the substrate and/or protect the mat material. Typically, catalytic converter studies only consider sound propagation in the small capillary tubes of the substrate. Investigations of the acoustic characteristics of entire catalytic converter assemblies (housing, substrate, seals, and mat) do not appear to be available. This work experimentally investigates the acoustic behavior of catalytic converter assemblies and the contributions of the separate components to sound attenuation. Experimental findings are interpreted with respect to available techniques for modeling sound propagation in ceramic substrates.

Dickey, Nolan S.; Selamet, Ahmet; Parks, Steve J.; Tallio, Kevin V.; Miazgowicz, Keith D.; Radavich, Paul M.

2003-10-01

499

Seismic response of steel suspension bridge  

SciTech Connect

Performing accurate, realistic numerical simulations of the seismic response of long-span bridges presents a significant challenge to the fields of earthquake engineering and seismology. Suspension bridges in particular represent some of the largest and most important man-made structures and ensuring the seismic integrity of these mega-structures is contingent on accurate estimations of earthquake ground motions and accurate computational simulations of the structure/foundation system response. A cooperative, multi-year research project between the Univ. of California and LLNL was recently initiated to study engineering and seismological issues essential for simulating the response of major structures. Part of this research project is focused on the response of the long-span bridges with the San Francisco-Oakland Bay Bridge serving as a case study. This paper reports on the status of this multi-disciplinary research project with emphasis on the numerical simulation of the transient seismic response of the Bay Bridge.

McCallen, D.B. [Lawrence Livermore National Lab., CA (United States); Astaneh-Asl, A. [California Univ., Berkeley, CA (United States). Dept. of Civil and Environmental Engineering

1996-11-01

500

5. DOWNSTREAM ELEVATION OF BRIDGE AND SUBSTRUCTURE (with graduated meter ...  

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

5. DOWNSTREAM ELEVATION OF BRIDGE AND SUBSTRUCTURE (with graduated meter pole); VIEW TO NORTH-NORTHEAST. - Auwaiakeakua Bridge, Spanning Auwaiakekua Gulch at Mamalahoa Highway, Waikoloa, Hawaii County, HI