Myocardial Bridge

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... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

Redox process catalysed by growing crystal-strengite, FePO4,2H2O, crystallizing from solution with iron(II) and hydroxylamine

Science.gov (United States)

Lundager Madsen, Hans Erik

2014-09-01

In an attempt to grow pure crystals of the iron(II) phosphate vivianite, Fe3(PO4)2,8H2O, from a solution of Mohr's salt, Fe(NH4)2(SO4)2,6H2O, added to a solution of ammonium phosphate, hydroxylammonium chloride, NH3OHCl, was added to the iron(II) stock solution to eliminate oxidation of iron(II) by oxygen from the air. However, the effect turned out to be the opposite of the expected: whereas hydroxylamine reduces iron(III) in bulk solution, it acted as a strong oxidant in the presence of growing iron phosphate crystals, causing the crystallization of the iron(III) phosphate strengite, FePO4,2H2O, as the only solid phase. Evidently the crystal surface catalyses oxidation of iron(II) by hydroxylamine. The usual composite kinetics of spiral growth and surface nucleation was found. The surface-nucleation part yielded edge free energy λ in the range 12-45 pJ/m, virtually independent of temperature and in the range typical for phosphates of divalent metals. The scatter of values for λ presumably arises from contributions from different crystal forms to the overall growth rate. The low mean value points to strong adsorption of iron(II), which is subsequently oxidized at the crystal surface, forming strengite. The state of the system did not tend to thermodynamic equilibrium, but to a metastable state, presumably controlled by the iron(II) rich surface layer of the crystal. In addition to crystal growth, it was possible to measure nucleation kinetics by light scattering (turbidimetry). A point of transition from heterogeneous to homogeneous nucleation was found, and from the results for the homogeneous domain a rather precise value of crystal surface free energy γ=55 mJ/m2 was found. This is a relatively low value as well, indicating that the redox process plays a role already at the nucleation stage.

High-Temperature Wide Thermal Hysteresis of an Iron(II Dinuclear Double Helicate

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Shiori Hora

2017-07-01

Full Text Available Two new dinuclear iron(II complexes (1·PF6 and 1·AsF6 of the general formula [FeII2(L2C32](X4·nH2O·mMeCN (X = PF6, n = m = 1.5 for 1·PF6 and X = AsF6, n = 3, m = 1 for 1·AsF6 have been prepared and structurally characterized, where L2C3 is a bis-1,2,3-triazolimine type Schiff-base ligand, 1,1′-[propane-1,3-diylbis(1H-1,2,3-triazole-1,4-diyl]bis{N-[2-(pyridin-2-ylethyl]methanimine}. Single crystal X-ray structure analyses revealed that 1·PF6 and 1·AsF6 are isostructural. The complex-cation [FeII2(L2C32]4+ of both has the same dinuclear double helicate architecture, in which each iron(II center has an N6 octahedral coordination environment. Neighboring helicates are connected by intermolecular π–π interactions to give a chiral one-dimensional (1D structure, and cationic 1D chains with the opposite chirality exist in the crystal lattice to give a heterochiral crystal. Magnetic and differential scanning calorimetry (DSC studies were performed only for 1·AsF6, since the thermal stability in a high-temperature spin crossover (SCO region of 1·PF6 is poorer than that of 1·AsF6. 1·AsF6 shows an unsymmetrical hysteretic SCO between the low-spin–low-spin (LS–LS and high-spin–high-spin (HS–HS states at above room temperature. The critical temperatures of warming (Tc↑ and cooling (Tc↓ modes in the abrupt spin transition area are 485 and 401 K, respectively, indicating the occurrence of 84 K-wide thermal hysteresis in the first thermal cycle.

Center Director Bridges visits Disability Awareness and Action working Group Technology Fair

Science.gov (United States)

1999-01-01

Center Director Roy Bridges (standing, center) poses with members of the Disability Awareness and Action Working Group (DAAWG), which is holding the 1999 Technology Fair Oct. 20-21 at Kennedy Space Center. The Fair is highlighting vendors demonstrating mobility, hearing, vision and silent disability assistive technology. The purpose is to create an awareness of the types of technology currently available to assist people with various disabilities in the workplace. The theme is that of this year's National Disability Employment Awareness Month, 'Opening Doors to Ability.' Some of the vendors participating are Canine Companions for Independence, Goodwill Industries, Accessible Structures, Division of Blind Services, Space Coast Center for Independent Living, KSC Fitness Center and Delaware North Parks Services.

X-ray diffraction study of phase transitions in iron(II) trisnioximate hexadecylboronate clathrochelate complex

International Nuclear Information System (INIS)

Vorontsov, I.I.; Antipin, M.Yu.; Dubovik, I.I.; Papkov, V.S.; Potekhin, K.A.; Voloshin, Ya.Z.; Stash, A.I.; Belsky, V.K.

2001-01-01

Crystals of the iron(II) nioximate hexadecylboronate clathrochelate complex-FeNx 3 (BHd ) 2 [tris(μ-1,2-cyclohexanedionedioximato-O:O ' )di-n-hexadecyldiborato(2-) - N,'''N''',N''',N''',N''',N ' ]iron(II) - are investigated by differential scanning calorimetry and X-ray diffraction. Two structural phase transitions are revealed at T cr1 = 290(3) K and T cr2 = 190(3) K. The crystal structures of phases I, II, and III are determined by X-ray diffraction analysis at 303, 243, and 153 K, respectively. It is demonstrated that the I ↔ II phase transition is due to a change in the system of translations, and the II ↔ III phase transition is accompanied only by a jumpwise change in the unit cell parameters. The possible mechanisms of phase transitions are discussed in terms of geometry and molecular packing of FeNx 3 (BHd) 2 in all three phases

Reaction path sampling of the reaction between iron(II) and hydrogen peroxide in aqueous solution

NARCIS (Netherlands)

Ensing, B.; Baerends, E.J.

2002-01-01

Previously, we have studied the coordination and dissociation of hydrogen peroxide with iron(II) in aqueous solution by Car-Parrinello molecular dynamics at room temperature. We presented a few illustrative reaction events, in which the ferryl ion ([Fe(IV)O

Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume

Energy Technology Data Exchange (ETDEWEB)

Toner, Brandy M.; Fakra, Sirine C.; Manganini, Steven J.; Santelli, Cara M.; Marcus, Matthew A.; Moffett, James W.; Rouxel, Olivier; German, Christopher R.; Edwards, Katrina J.

2008-09-20

Hydrothermal venting associated with mid-ocean ridge volcanism is globally widespread. This venting is responsible for a dissolved iron flux to the ocean that is approximately equal to that associated with continental riverine runoff. For hydrothermal fluxes, it has long been assumed that most of the iron entering the oceans is precipitated in inorganic forms. However, the possibility of globally significant fluxes of iron escaping these mass precipitation events and entering open-ocean cycles is now being debated, and two recent studies suggest that dissolved organic ligands might influence the fate of hydrothermally vented metals. Here we present spectromicroscopic measurements of iron and carbon in hydrothermal plume particles at the East Pacific Rise mid-ocean ridge. We show that organic carbon-rich matrices, containing evenly dispersed iron(II)-rich materials, are pervasive in hydrothermal plume particles. The absence of discrete iron(II) particles suggests that the carbon and iron associate through sorption or complexation. We suggest that these carbon matrices stabilize iron(II) released from hydrothermal vents in the region, preventing its oxidation and/or precipitation as insoluble minerals. Our findings have implications for deep-sea biogeochemical cycling of iron, a widely recognized limiting nutrient in the oceans.

Comparative analysis of electron-density and electron-localization function for dinuclear manganese complexes with bridging boron- and carbon-centered ligands.

Science.gov (United States)

Götz, Kathrin; Kaupp, Martin; Braunschweig, Holger; Stalke, Dietmar

2009-01-01

Bonding in borylene-, carbene-, and vinylidene-bridged dinuclear manganese complexes [MnCp(CO)(2)](2)X (X = B-tBu, B = NMe(2), CH(2), C=CH(2)) has been compared by analyses based on quantum theory of atoms in molecules (QTAIM), on the electron-localization function (ELF), and by natural-population analyses. All of the density functional theory based analyses agree on the absence of a significant direct Mn-Mn bond in these complexes and confirm a dominance of delocalized bonding via the bridging ligand. Interestingly, however, the topology of both charge density and ELF related to the Mn-bridge-Mn bonding depend qualitatively on the chosen density functional (except for the methylene-bridged complex, which exhibits only one three-center-bonding attractor both in -nabla(2)rho and in ELF). While gradient-corrected functionals provide a picture with localized two-center X-Mn bonding, increasing exact-exchange admixture in hybrid functionals concentrates charge below the bridging atom and suggests a three-center bonding situation. For example, the bridging boron ligands may be described either as substituted boranes (e.g., at BLYP or BP86 levels) or as true bridging borylenes (e.g., at BHLYP level). This dependence on the theoretical level appears to derive from a bifurcation between two different bonding situations and is discussed in terms of charge transfer between X and Mn, and in the context of self-interaction errors exhibited by popular functionals.

Bridge resource program.

Science.gov (United States)

2013-09-01

The mission of Rutgers Universitys Center for Advanced Infrastructure and Transportation (CAIT) Bridge Resource Program (BRP) is to provide bridge engineering support to the New Jersey Department of Transportation (NJDOT)s Bridge Engineering an...

Direct synthesis of magnetite nanoparticles from iron(II) carboxymethylcellulose and their performance as NMR contrast agents

Energy Technology Data Exchange (ETDEWEB)

Gomes da Silva, Delmarcio; Hiroshi Toma, Sergio; Menegatti de Melo, Fernando [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil); Carvalho, Larissa Vieira C.; Magalhães, Alvicler; Sabadini, Edvaldo [Instituto de Química, Universidade Estadual de Campinas – UNICAMP, Campinas, SP (Brazil); Domingues dos Santos, Antônio [Instituto de Física, Universidade de São Paulo, São Paulo, SP (Brazil); Araki, Koiti [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil); Toma, Henrique E., E-mail: henetoma@iq.usp.br [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil)

2016-01-01

Iron(II) carboxymethylcellulose (CMC) has been successfully employed in the synthesis of hydrophylic magnetite nanoparticles stabilized with a biopolymer coating, aiming applications in NMR imaging. The new method encompasses a convenient one-step synthetic procedure, allowing a good size control and yielding particles of about 10 nm (core size). In addition to the biocompatibility, the nanoparticles have promoted a drastic reduction in the transverse relaxation time (T{sub 2}) of the water protons. The relaxivity rates have been investigated as a function of the nanoparticles concentration, showing a better performance in relation to the common NMR contrast agents available in the market. - Highlights: • Stable, hydrophylic magnetic nanoparticles have been obtained. • Direct use of iron(II) carboxymethylcellulose improves the synthesis. • The magnetic nanoparticles exhibit high spin–spin relaxivity. • The particles promote dark contrast by decreasing the T{sub 2} relaxation time.

Bridging Anticoagulation

Science.gov (United States)

... clinical centers in the United States, Canada, and Brazil. A more detailed description of the study is ... Your Personal Message Send Message Share on Social Media Bridging Anticoagulation The BRIDGE Study Investigators Circulation. 2012; ...

Bridging the Gap: Adaptive Games and Student-Centered VLEs

Science.gov (United States)

Del Blanco, Ángel; Torrente, Javier; Moreno-Ger, Pablo; Fernández-Manjón, Baltasar

The widely used e-learning technology is facing new challenges such as how to produce student-centered systems that can be adapted to the needs of each student. Those objectives should be met in a standard compliant way to simplify general adoption. In this context, educational videogames are proposed as an ideal medium to facilitate adaptation and tracking of the students’ performance for assessment purposes. However, there are still barriers between the gaming and e-learning worlds preventing their mutual interaction. In this paper we propose a middleware to bridge this gap, integrating adaptive educational videogames in e-learning environments with a special focus on the ongoing standardization efforts.

Immobilized Tannin from Sanseviera trifasciata on Carbon as Adsorbent For Iron(II in Polluted Water Source

Directory of Open Access Journals (Sweden)

Irfan Hanafi Arif

2016-03-01

Full Text Available The organic-agricultural waste resulted from local farmer or community gardening recently paid public attention. The presence and easily grown of “Lidah Mertua” or Sanseviera trifasciata being focused on potency investigation for its prospecting application. It was reported contain some phenolic and also tannin extracted from aqueous solvents. This paper revealed recent investigation applying of its isolated tannin from leave part to modifying of activated carbon. The previous report published that carbon were able to adsorb some toxic heavy metals. However, it has some limitation including lower capacity adsorption. Impregnated or immobilized the tannin-isolated from S. trifasciata leaves was able to modify the carbon functionality, physical appearance, pores size, and it adsorption capacity. Both Langmuir and Freundlich adsorption mechanism model also disclosed the developed adsorbent mechanism of iron(II adsorption on the adsorbent tannin-immobolized on carbon. The real test using community well drilling water source also gave important finding on the concentration of iron(II contained on water source.

Effect of Phosphorylation and Copper(II or Iron(II Ions Enrichment on Some Physicochemical Properties of Spelt Starch

Directory of Open Access Journals (Sweden)

Jacek Rożnowski

Full Text Available ABSTRACT: This paper provides an assessment of the effect of saturation of spelt starch and monostarch phosphate with copper or iron ions on selected physicochemical properties of the resulting modified starches. Native and modified spelt starch samples were analyzed for selected mineral element content using Atomic Absorption Spectroscopy (AAS. Thermodynamic properties were measured using DSC, and pasting properties by RVA. Flow curves of 5% pastes were plotted and described using the Herschel-Bulkley model. The structure recovery ratio was measured. AAS analysis established the presence of iron(II and copper(II ions in the samples of modified starches and that potassium and magnesium ions had leached from them. In comparison to unfortified samples, enriching native starch with copper(II ions decreases value of all temperatures of phase transformation about 1.3-2.7 °C, but in case of monostarch phosphates bigger changes (2.8-3.7 °C were observed. Fortified native spelt starch with copper(II ions caused increasing the final viscosity of paste from 362 to 429 mPa·s. However, presence iron(II ions in samples caused reduced its final viscosity by 170 (spelt starch and 103 mPa·s (monostarch phosphate. Furthermore, enriching monostarch phosphate contributed to reduce degree of structure recovery of pastes from 70.9% to 66.6% in case of copper(II ions and to 59.9% in case of iron(II ions.

Design and synthesis of a tetradentate '3-amine-1-carboxylate' ligand to mimic the metal binding environment at the non-heme iron(II) oxidase active site.

Science.gov (United States)

Dungan, Victoria J; Ortin, Yannick; Mueller-Bunz, Helge; Rutledge, Peter J

2010-04-07

Non-heme iron(II) oxidases (NHIOs) catalyse a diverse array of oxidative chemistry in Nature. As part of ongoing efforts to realize biomimetic, iron-mediated C-H activation, we report the synthesis of a new 'three-amine-one-carboxylate' ligand designed to complex with iron(II) and mimic the NHIO active site. The tetradentate ligand has been prepared as a single enantiomer in nine synthetic steps from N-Cbz-L-alanine, pyridine-2,6-dimethanol and diphenylamine, using Seebach oxazolidinone chemistry to control the stereochemistry. X-Ray crystal structures are reported for two important intermediates, along with variable temperature NMR experiments to probe the hindered interconversion of conformational isomers of several key intermediates, 2,6-disubstituted pyridine derivatives. The target ligand and an N-Cbz-protected precursor were each then complexed with iron(II) and tested for their ability to promote alkene dihydroxylation, using hydrogen peroxide as the oxidant.

Moessbauer study of some iron(II) complexes with methyl isocyanide, bipyridine and phenanthroline

Energy Technology Data Exchange (ETDEWEB)

Calogero, S [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi; Russo, U [Padua Univ. (Italy). Istituto di Chimica Generale ed Inorganica e di Chimica Inorganica Industriale; Fragala, I [Catania Univ. (Italy). Istituto di Chimica Generale

1979-06-01

Moessbauer parameters for hexacoordinate iron(II) complexes of the type (Fe(N-N)sub(n)(CNMe)sub(m)) (ClO/sub 4/)/sub 2/(m=6, 4, 2 or 0; n=0, 1, 2 or 3; N-N=2.2'-bipyridine or 1.10-phenanthroline) have been determined. Treatment by a point-charge model including distortions has been carried out in order to rationalize the quadrupole splittings. A computer program has been developed to handle variable geometry systems.

Mechanical circulatory support as a bridge to cardiac retransplantation: a single center experience.

Science.gov (United States)

Clerkin, Kevin J; Thomas, Sunu S; Haythe, Jennifer; Schulze, P Christian; Farr, Maryjane; Takayama, Hiroo; Jorde, Ulrich P; Restaino, Susan W; Naka, Yoshifumi; Mancini, Donna M

2015-02-01

Cardiac retransplantation is increasing in frequency. Recent data have shown that retransplantation outcomes are now comparable with primary transplantation. The use of mechanical circulatory support (MCS) as a bridge to retransplantation has similar post-retransplant outcomes to those without MCS, but the success of bridging patients to retransplant with MCS has not been well studied. From January 2000 to February 2014 at Columbia University Medical Center, 84 patients were listed for retransplantation. Of this cohort, 48 patients underwent retransplantation, 15 were bridged with MCS, 24 died, and 6 clinically improved. A retrospective analysis was performed examining waiting list time, survival to retransplantation, and survival after retransplant. The effect of the United Network of Organ Sharing (UNOS) allocation policy change in 2006 on waiting list time and MCS use was also investigated. Of 48 patients who underwent retransplantation, 11 were bridged with MCS. Overall 1-year survival to retransplantation was 81.3%. There was no significant difference in waiting list survival (p = 0.71) in those with and without MCS. Death from cardiac arrest or multiorgan failure with infection was more frequent in the medically managed group (p = 0.002). After the UNOS 2006 allocation policy change, waiting list time (599 ± 936 days in Era 1 vs 526 ± 498 days in Era 2, p = 0.65) and waiting list survival (p = 0.22) between eras were comparable, but there was a trend toward greater use of MCS (p = 0.13). Survival after retransplant was acceptable. The use of MCS as a bridge to cardiac retransplantation is a reasonable strategy. Copyright © 2015 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Field performance of timber bridges. 9, Big Erick`s stress-laminated deck bridge

Science.gov (United States)

J. A. Kainz; J. P. Wacker; M. Nelson

The Big Erickas bridge was constructed during September 1992 in Baraga County, Michigan. The bridge is 72 ft long, 16 ft wide, and consists of three simple spans: two stress-laminated deck approach spans and a stress-laminated box center span. The bridge is unique in that it is one of the first known stress-laminated timber bridge applications to use Eastern Hemlock...

Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method

International Nuclear Information System (INIS)

2004-01-01

This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 2. of ISO 7097 describes procedures for determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with cerium(IV) and ISO 7097-1 uses a titration with potassium dichromate

Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids - Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method

International Nuclear Information System (INIS)

2004-01-01

This first edition of ISO 7097-1 together with ISO 7097-2:2004 cancels and replaces ISO 7097:1983, which has been technically revised, and ISO 9989:1996. ISO 7097 consists of the following parts, under the general title Nuclear fuel technology - Determination of uranium in solutions, uranium hexafluoride and solids: Part 1: Iron(II) reduction/potassium dichromate oxidation titrimetric method; Part 2: Iron(II) reduction/cerium(IV) oxidation titrimetric method. This part 1. of ISO 7097 describes procedures for the determination of uranium in solutions, uranium hexafluoride and solids. The procedures described in the two independent parts of this International Standard are similar: this part uses a titration with potassium dichromate and ISO 7097-2 uses a titration with cerium(IV)

Extracorporeal life support as a bridge to lung transplantation-experience of a high-volume transplant center.

Science.gov (United States)

Hoetzenecker, Konrad; Donahoe, Laura; Yeung, Jonathan C; Azad, Sassan; Fan, Eddy; Ferguson, Niall D; Del Sorbo, Lorenzo; de Perrot, Marc; Pierre, Andrew; Yasufuku, Kazuhiro; Singer, Lianne; Waddell, Thomas K; Keshavjee, Shaf; Cypel, Marcelo

2018-03-01

Extracorporeal life support (ECLS) is increasingly used to bridge deteriorating patients awaiting lung transplantation (LTx), however, few systematic descriptions of this practice exist. We therefore aimed to review our institutional experience over the past 10 years. In this case series, we included all adults who received ECLS with the intent to bridge to LTx. Data were retrieved from patient charts and our institutional ECLS and transplant databases. Between January 2006 and September 2016, 1111 LTx were performed in our institution. ECLS was used in 71 adults with the intention to bridge to LTx; of these, 11 (16%) were bridged to retransplantation. The median duration of ECLS before LTx was 10 days (range, 0-95). We used a single dual-lumen venous cannula in 23 patients (32%). Nine of 13 patients (69%) with pulmonary hypertension were bridged by central pulmonary artery to left atrium Novalung. Twenty-five patients (35%) were extubated while on ECLS and 26 patients (37%) were mobilized. Sixty-three patients (89%) survived to LTx. Survival by intention to treat was 66% (1 year), 58% (3 years) and 48% (5 years). Survival was significantly shorter in patients undergoing ECLS bridge to retransplantation compared with first LTx (median survival, 15 months (95% CI, 0-31) versus 60 months (95% CI, 37-83); P = .041). In our center experience, ECLS bridge to first lung transplant leads to good short-term and long-term outcomes in carefully selected patients. In contrast, our data suggest that ECLS as a bridge to retransplantation should be used with caution. Copyright © 2017 The American Association for Thoracic Surgery. All rights reserved.

Oxidative degradation of the organometallic iron(II) complex [Fe{bis[3-(pyridin-2-yl)-1H-imidazol-1-yl]methane}(MeCN)(PMe3)](PF6)2: structure of the ligand decomposition product trapped via coordination to iron(II).

Science.gov (United States)

Haslinger, Stefan; Pöthig, Alexander; Cokoja, Mirza; Kühn, Fritz E

2015-12-01

Iron is of interest as a catalyst because of its established use in the Haber-Bosch process and because of its high abundance and low toxicity. Nitrogen-heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron-NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1'-bis(pyridin-2-yl)-2,2-bi(1H-imidazole)-κN(3)][3,3'-bis(pyridin-2-yl-κN)-1,1'-methanediylbi(1H-imidazol-2-yl-κC(2))](trimethylphosphane-κP)iron(II) bis(hexafluoridophosphate), [Fe(C17H14N6)(C16H12N6)(C3H9P)](PF6)2, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C-C-coupled biimidazole, is trapped by coordination to still-intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.

Oxygen reduction reaction at MWCNT-modified nanoscale iron(II) tetrasulfophthalocyanine: remarkable performance over platinum and tolerance toward methanol in alkaline medium

CSIR Research Space (South Africa)

Fashedemi, OO

2015-04-01

Full Text Available A nanoscale iron(II) tetrasulfophthalocyanine (nanoFeTSPc) catalyst obtained by co-ordinating with hexadecyltrimethylammonium bromide and subsequently anchored onto multi-walled carbon nanotubes (MWCNTs) for oxygen reduction reaction (ORR) has been...

Mechanism of redox reactions induced by light and electron pulse in solutions of mixed ligand iron(II) complex cyanides

International Nuclear Information System (INIS)

Horvath, A.; Szoeke, J.; Wojnarovits, L.

1991-01-01

Redox reactions induced by light and electron pulse have been studied in aqueous solutions of mixed ligand iron(II) complex cyanides. The short lived intermediates have been identified by time resolved specroscopy, the results of detailed kinetic analysis have been discussed. (author) 6 refs.; 3 figs.; 2 tabs

KSC Center Director Bridges accepts an ISO 9001 certificate from DNV

Science.gov (United States)

1998-01-01

Center Director Roy Bridges displays the ISO 9001 certificate he was awarded by Det Norske Veritas (DNV), Inc., an international ISO certification organization, at a ceremony at KSC. Dalton Lyon of DNV made the presentation, which included a 2000th ISO Certificate Plaque. ISO 9001 comprises the most detailed, comprehensive set of standard requirements for quality programs established by the International Standards Organization. The presentation followed a successful independent audit by DNV of the KSC Management System in May of this year. The third-party auditors examined about 20 elements of KSC's system, including management responsibility, design control, documentation, test and inspection, and corrective action procedures. DNV found that KSC met or exceeded the stringent quality standards in all areas. KSC will use this certification as a tool to improve an already world-class team. All NASA centers are required by NASA Administrator Daniel S. Goldin to be ISO 9001 registered by September 1999. NASA is the first federal agency to seek the quality certification.

Iodometric determination of peroxydiphosphate in the presence of copper(II) or iron(II) as catalyst.

Science.gov (United States)

Kapoor, S; Sharma, P D; Gupta, Y K

1975-09-01

Peroxydiphosphate can be determined iodometrically in the presence of a large excess of potassium iodide with copper(II) or iron(II) as catalyst through the operation of the Cu(II)/Cu(I) or Fe(II)/Fe(III) cycle. The method is applicable in HClO(4), H(2)SO(4), HCl and CH(3)COOH acid media in the range 0.1-1.0M studied. Nickel, manganese(II), cobalt(II), silver, chloride and phosphate are without effect.

Effects of Selected Dietary Secondary Metabolites on Reactive Oxygen Species Production Caused by Iron(II Autoxidation

Directory of Open Access Journals (Sweden)

Vladimir Chobot

2014-12-01

Full Text Available Iron is an essential co-factor for many enzymes that catalyze electron transfer reactions. It is well known that so-called “poorly liganded” iron can increase ROS concentrations and trigger oxidative stress that is capable of initiating apoptosis. Conversely, controlled ROS production has been recognized as an integral part of cellular signaling. Elevated ROS concentrations are associated with aging, inflammatory and degenerative diseases. Anti-aging properties have been attributed especially to antioxidant phenolic plant metabolites that represent food additives in our diet. Consequently, this study explores the effects of flavonoids (quercetin and rutin, several phenolic acids (caffeic, chlorogenic, and protocatechuic acid, and the alkaloid caffeine on iron(II autoxidation and ROS production in comparison to the standard antioxidants ascorbic acid and Trolox. The iron(II autoxidation assay was carried out in pH 6.0 (plant apoplast and inflamed human tissue and 7.4 (cell cytoplasm and human blood plasma. The obtained results accentuate phenolic acids as the more specific antioxidants compared to ascorbic acid and Trolox. Flavonoid redox chemistry depends more on the chemical milieu, specifically on pH. In vivo, the presence of iron cannot be ruled out and “wrongly” or “poorly” complexed iron has been pointed out as causative agent of various age-related diseases.

Dimerization of Terminal Aryl Alkynes Catalyzed by Iron(II) Amine-Pyrazolyl Tripodal Complexes with E/Z Selectivity Controlled by tert-Butoxide

KAUST Repository

Xue, Fei

2018-05-09

The catalytic activity of iron(II) complexes with functionalized amine-pyrazolyl tripodal ligands toward dimerization of terminal alkynes in the presence a base (KOtBu or NaOtBu) has been studied. An unusual E/Z selectivity of the reaction determined by tert-butoxide was observed.

Dimerization of Terminal Aryl Alkynes Catalyzed by Iron(II) Amine-Pyrazolyl Tripodal Complexes with E/Z Selectivity Controlled by tert-Butoxide

KAUST Repository

Xue, Fei; Song, Xiaolu; Lin, Ting Ting; Munkerup, Kristin; Albawardi, Saad Fahad; Huang, Kuo-Wei; Hor, T. S. Andy; Zhao, Jin

2018-01-01

The catalytic activity of iron(II) complexes with functionalized amine-pyrazolyl tripodal ligands toward dimerization of terminal alkynes in the presence a base (KOtBu or NaOtBu) has been studied. An unusual E/Z selectivity of the reaction determined by tert-butoxide was observed.

The preparation of magnetite from iron(III) and iron(II) salt solutions

International Nuclear Information System (INIS)

Segal, D.L.

1980-10-01

Methods are described for the preparation of magnetite from iron(III) and iron(II) salt solutions at temperatures between 295 to 373 K. The effect of the reagent concentration, a chelating agent and different alkali-metal cations on the formation of magnetite has been investigated. The magnetite samples have been examined by X-ray diffraction, transmission electron microscopy, adsorption of nitrogen, emission spectroscopy, X-ray photoelectron spectroscopy and by determination of the point of zero charge. A review of previous work on the preparation of magnetite in an aqueous environment is also included. This work is relevant to the corrosion processes which can occur in the water coolant circuits of nuclear reactors. (author)

Electrochemical characterization of mixed self-assembled films of water-soluble single-walled carbon nanotube-poly(m-aminobenzene sulfonic acid) and Iron(II) tetrasulfophthalocyanine

CSIR Research Space (South Africa)

Agboola, BO

2010-09-01

Full Text Available The redox activities of water-soluble iron(II) tetrasulfophthalocyanine (FeTSPc) and single-walled carbon nanotube-poly(m-aminobenzene sulfonic acid) (SWCNT-PABS) adsorbed on a gold surface precoated with a self-assembled monolayer (SAM) of 2...

Ternary iron(II) complex with an emissive imidazopyridine arm from Schiff base cyclizations and its oxidative DNA cleavage activity.

Science.gov (United States)

Mukherjee, Arindam; Dhar, Shanta; Nethaji, Munirathinam; Chakravarty, Akhil R

2005-01-21

The ternary iron(II) complex [Fe(L')(L")](PF6)3(1) as a synthetic model for the bleomycins, where L' and L" are formed from metal-mediated cyclizations of N,N'-(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine)(L), is synthesized and structurally characterized by X-ray crystallography. In the six-coordinate iron(ii) complex, ligands L' and L" show tetradentate and bidentate chelating modes of bonding. Ligand L' is formed from an intramolecular attack of the alcoholic OH group of L to one imine moiety leading to the formation of a stereochemically constrained five-membered ring. Ligand L" which is formed from an intermolecular reaction involving one imine moiety of L and pyridine-2-carbaldehyde has an emissive cationic imidazopyridine pendant arm. The complex binds to double-stranded DNA in the minor groove giving a Kapp value of 4.1 x 10(5) M(-1) and displays oxidative cleavage of supercoiled DNA in the presence of H2O2 following a hydroxyl radical pathway. The complex also shows photo-induced DNA cleavage activity on UV light exposure involving formation of singlet oxygen as the reactive species.

KSC Center Director Bridges accepts an ISO 9001 certification plaque from DNV

Science.gov (United States)

1998-01-01

Center Director Roy Bridges (right) displays the 2000th ISO Certificate Plaque he was given by Dalton Lyon (left) of Det Norske Veritas (DNV), Inc., an international ISO certification organization, at a ceremony at KSC. The plaque is a representation of the ISO 9001 certification awarded to KSC by DNV. ISO 9001 comprises the most detailed, comprehensive set of standard requirements for quality programs established by the International Standards Organization. The presentation followed a successful independent audit by DNV of the KSC Management System in May of this year. The third-party auditors examined about 20 elements of KSC's system, including management responsibility, design control, documentation, test and inspection, and corrective action procedures. DNV found that KSC met or exceeded the stringent quality standards in all areas. KSC will use this certification as a tool to improve an already world- class team. All NASA centers are required by NASA Administrator Daniel S. Goldin to be ISO 9001 registered by September 1999. NASA is the first federal agency to seek the quality certification.

33 CFR 118.85 - Lights on vertical lift bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on vertical lift bridges... BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.85 Lights on vertical lift bridges. (a) Lift span lights. The vertical lift span of every vertical lift bridge shall be lighted so that the center of the...

Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

KAUST Repository

Chinnusamy, Tamilselvi R.; Rodionov, Valentin; Kü hn, Fritz; Reiser, Oliver

2012-01-01

The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient

Neighborhood Bridges: 2010-2011 Evaluation Report

Science.gov (United States)

Ingram, Debra

2011-01-01

In 2010-2011, students in twenty-five classrooms from eleven schools in the Minneapolis-Saint Paul metropolitan area participated in The Children's Theatre Company's Neighborhood Bridges (Bridges) program. The Children's Theatre Company contracted with the University of Minnesota's Center for Applied Research and Educational Improvement (CAREI) to…

Synthesis and antimalarial activity of metal complexes of cross-bridged tetraazamacrocyclic ligands.

Science.gov (United States)

Hubin, Timothy J; Amoyaw, Prince N-A; Roewe, Kimberly D; Simpson, Natalie C; Maples, Randall D; Carder Freeman, TaRynn N; Cain, Amy N; Le, Justin G; Archibald, Stephen J; Khan, Shabana I; Tekwani, Babu L; Khan, M O Faruk

2014-07-01

Using transition metals such as manganese(II), iron(II), cobalt(II), nickel(II), copper(II), and zinc(II), several new metal complexes of cross-bridged tetraazamacrocyclic chelators namely, cyclen- and cyclam-analogs with benzyl groups, were synthesized and screened for in vitro antimalarial activity against chloroquine-resistant (W2) and chloroquine-sensitive (D6) strains of Plasmodium falciparum. The metal-free chelators tested showed little or no antimalarial activity. All the metal complexes of the dibenzyl cross-bridged cyclam ligand exhibited potent antimalarial activity. The Mn(2+) complex of this ligand was the most potent with IC50s of 0.127 and 0.157μM against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) P. falciparum strains, respectively. In general, the dibenzyl hydrophobic ligands showed better anti-malarial activity compared to the activity of monobenzyl ligands, potentially because of their higher lipophilicity and thus better cell penetration ability. The higher antimalarial activity displayed by the manganese complex for the cyclam ligand in comparison to that of the cyclen, correlates with the larger pocket of cyclam compared to that of cyclen which produces a more stable complex with the Mn(2+). Few of the Cu(2+) and Fe(2+) complexes also showed improvement in activity but Ni(2+), Co(2+) and Zn(2+) complexes did not show any improvement in activity upon the metal-free ligands for anti-malarial development. Published by Elsevier Ltd.

Iron(II) complexes of new hexadentate 1,1,1-tris-(iminomethyl)ethane podands, and their 7-methyl-1,3,5-triazaadamantane rearrangement products.

Science.gov (United States)

Diener, Sara A; Santoro, Amedeo; Kilner, Colin A; Loughrey, Jonathan J; Halcrow, Malcolm A

2012-04-07

New iron(II) podand complexes have been prepared, by condensation of 2-(aminomethyl)-2-methyl-1,3-diaminopropane with 3 equiv of a heterocyclic aldehyde in the presence of hydrated Fe[BF(4)](2) or Fe[ClO(4)](2) as templates. The 2-(aminomethyl)-2-methyl-1,3-diaminopropane is prepared in situ by deprotonation of its trihydrochloride salt. The chloride must be removed from these reactions by precipitation with silver, to avoid the formation of the alternative 2,4,6-trisubstituted-7-methyl-1,3,5-triazaadamantane condensation products, or their FeCl(2) adducts. The crystal structures of two 2,4,6-tri(pyridyl)-7-methyl-1,3,5-triazaadamantane-containing species are presented, and contain two different geometric isomers of this tricyclic ring with three equatorial, or two equatorial and one axial, pyridyl substituents. Both structures feature strong C-HX (X = Cl or F) hydrogen bonding from the aminal C-H groups in the triazaadamantane ring. Five iron(II) podand complexes were successfully obtained, all of which contain low-spin iron centres.

Saline-water bioleaching of chalcopyrite with thermophilic, iron(II)- and sulfur-oxidizing microorganisms.

Science.gov (United States)

Watling, Helen R; Collinson, David M; Corbett, Melissa K; Shiers, Denis W; Kaksonen, Anna H; Watkin, Elizabeth L J

2016-09-01

The application of thermoacidophiles for chalcopyrite (CuFeS2) bioleaching in hot, acidic, saline solution was investigated as a possible process route for rapid Cu extraction. The study comprised a discussion of protective mechanisms employed for the survival and/or adaptation of thermoacidophiles to osmotic stress, a compilation of chloride tolerances for three genera of thermoacidophiles applied in bioleaching and an experimental study of the activities of three species in a saline bioleaching system. The data showed that the oxidation rates of iron(II) and reduced inorganic sulfur compounds (tetrathionate) were reduced in the presence of chloride levels well below chloride concentrations in seawater, limiting the applicability of these microorganisms in the bioleaching of CuFeS2 in saline water. Copyright © 2016. Published by Elsevier Masson SAS.

STS-95 Commander Brown presents a photo to Center Director Bridges

Science.gov (United States)

1998-01-01

STS-95 Commander Curtis L. Brown Jr. (left) presents a composite photograph of images taken during the STS-95 mission to Kennedy Space Center (KSC) Director Roy Bridges in the Training Auditorium. The auditorium is filled with KSC employees who were invited to hear the crew describe their experiences during their successful mission dedicated to microgravity research and to view a videotape of the highlights of the mission. The other crew members are Pilot Steven W. Lindsey; Mission Specialist and Payload Commander Stephen K. Robinson; Mission Specialists Scott E. Parazynski and Pedro Duque, with the European Space Agency (ESA); and Payload Specialists Chiaki Mukai, with the National Space Development Agency of Japan (NASDA), and John H. Glenn Jr., a senator from Ohio and one of the original seven Project Mercury astronauts. Later in the afternoon, the crew will participate in a parade down State Road A1A in nearby Cocoa Beach, reminiscent of those held after missions during the Mercury Program.

Single-center experience of the bridge-to-bridge strategy using the Nipro paracorporeal ventricular assist device.

Science.gov (United States)

Yoshitake, Shuichi; Kinoshita, Osamu; Nawata, Kan; Hoshino, Yasuhiro; Itoda, Yoshifumi; Kimura, Mitsutoshi; Yamauchi, Haruo; Ono, Minoru

2018-06-25

Currently, we use the Nipro paracorporeal VAD (p-VAD) for initial short-term ventricular support, as a bridge to decision (BTD) or a bridge to candidacy (BTC) treatment, in Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) levels 1 and 2 patients. However, it is possible that compared to patients with primary implantable-VADs (P-iVAD), the bridge-to-bridge (BTB) patients are more likely to develop complications. This retrospective study used data from 24 consecutive BTB patients who were initially implanted with Nipro p-VAD as BTD or BTC treatments between April 2011 and March 2016, and subsequently underwent conversion to an i-VAD. The data from 72 patients who underwent a primary i-VAD (P-iVAD) procedure were used for comparison. Between the two groups, there was no significant difference in the incidence of infectious events (p = 0.72) or stroke (p = 0.44). Orthotropic heart transplantation was performed in 6 of the 24 patients in the BTB group and in 21 of the 72 patients in the P-iVAD group. The 1- and 2-year survival rates were 95.8% and 95.8% in the BTB group and 91% and 85.8% in the P-iVAD group; these values were not significantly different between groups (p = 0.91). Based on these results we conclude that BTB using Nipro p-VAD is a reasonable strategy for treating patients with severe decompensated end-stage heart failure.

Railroad Bridges in Louisiana, Geographic NAD83, FEMA (1997) [railroad_bridges_FEMA_1997

Data.gov (United States)

Louisiana Geographic Information Center — This is is a point dataset for the locations and attributes of 32 Louisiana railroad bridges. The attributes include city (nearest?), county (sic), routefrom (city),...

Large-scale synthesis of high-purity well-aligned carbon nanotubes using pyrolysis of iron(II) phthalocyanine and acetylene

Science.gov (United States)

Liu, B. C.; Lee, T. J.; Lee, S. H.; Park, C. Y.; Lee, C. J.

2003-08-01

Well-aligned carbon nanotubes (CNTs) with high purity have been produced by pyrolysis of iron(II) phthalocyanine and acetylene at 800 °C. The synthesized CNTs have a length of 75 μm and diameters ranging from 20 to 60 nm. The CNTs have a bamboo-like structure and exhibit good crystallinity of graphite sheets. The growth rate of the CNTs was rapidly increased with adding C 2H 2. Our results demonstrate that the proposed growth method is suitable to large-scale synthesis of high-purity well-aligned CNTs on various substrates.

The Bridge: Experiments in Science and Art, Experiences from the 2017 SciArt Center Cross-Disciplinary Residency Program

Science.gov (United States)

Shipman, J. S.; Chalmers, R.; Buntaine, J.

2017-12-01

Cross-disciplinary programs create the opportunity to explore new realms for scientists and artists alike. Through the collaborative process, artistic insights enable innovative approaches to emotionally connect to and visualize the world around us. Likewise, engagement across the art-science spectrum can lead to shifts in scientific thinking that create new connections in data and drive discoveries in research. The SciArt Center "The Bridge Residency Program" is a four-month long virtual residency open internationally for professionals in the arts and sciences to facilitate cross-disciplinary work and to bring together like-minded participants. The SciArt Center provides a virtual space to record and showcase the process and products of each collaboration. The work is facilitated with biweekly Skype calls and documented with weekly blog posts. Residents create either digital or physical products and share via video, images, or direct mailing with their collaborators. Past projects have produced call and response discussion, websites, skills and conference presentations, science-art studies, virtual exhibits, art shows, dance performances, and research exchange. Here we present the creative process and outcomes of one of the four collaborative teams selected for the 2017 residency. Jill Shipman, a Ph.D. Candidate in Volcanology who is also active in filmmaking and theatrical productions and Rosemary Chalmers, a UK-based lecturer, concept artist, and illustrator with a specialty in creature design. They were paired together for their shared interest in storytelling, illustration, and unique geological and environmental habitats and the life that occupies them. We will discuss the collaborative project developed by this team during their recent residency and illustrate how a virtual program can bridge the distance between geographical location to foster science and art collaboration. To follow the progress of the residency please visit: http://www.sciartcenter.org/the-bridge.html

Iron(II) tris(3-bromo-1,10-phenanthroline) complex:synthesis, crystal structure and electropolymerization

CERN Document Server

Lee, K J; Lee, S S; Lee, B Y

2002-01-01

The complex of iron(II) tris(3-Br-phen)(3-Br-phen; 3-bromo-1,10-phenanthroline) was prepared as a precursor of electropolymerization and the crystal structure of [Fe(3-Br-phen) sub 3](PF sub 6) sub 2 centre dot CH sub 3 CN with a distorted octahedral geometry has been investigated. The reductive electropolymerization of [Fe(3-Br-phen) sub 3] sup 2 sup + complex onto the surface of a glassy carbon electrode and indium tin oxide (ITO) optically transparent electrode were performed in acetonitrile at room temperature. Thin film of poly-[Fe(3-Br-phen) sub 3] sup 2 sup + formed was adherent, electroactive and stably deposited on a glassy carbon disk electrode. The thin metallopolymeric film formed was also confirmed by absorption spectroscopy.

Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy.

Science.gov (United States)

Marasco, Silvana F; Lo, Casey; Murphy, Deirdre; Summerhayes, Robyn; Quayle, Margaret; Zimmet, Adam; Bailey, Michael

2016-01-01

In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long-term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge-to-bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end-organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous-flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty-three patients required ECLS support pre-LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end-organ function pre-VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end-organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these "crash and burn" patients. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Nonanuclear Spin-Crossover Complex Containing Iron(II) and Iron(III) Based on a 2,6-Bis(pyrazol-1-yl)pyridine Ligand Functionalized with a Carboxylate Group.

Science.gov (United States)

Abhervé, Alexandre; Recio-Carretero, María José; López-Jordà, Maurici; Clemente-Juan, Juan Modesto; Canet-Ferrer, Josep; Cantarero, Andrés; Clemente-León, Miguel; Coronado, Eugenio

2016-09-19

The synthesis and magnetostructural characterization of [Fe(III)3(μ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](ClO4)13·(CH3)2CO)6·(solvate) (2) are reported. This compound is obtained as a secondary product during synthesis of the mononuclear complex [Fe(II)(bppCOOH)2](ClO4)2 (1). The single-crystal X-ray diffraction structure of 2 shows that it contains the nonanuclear cluster of the formula [Fe(III)3(μ3-O)(H2O)3[Fe(II)(bppCOOH)(bppCOO)]6](13+), which is formed by a central Fe(III)3O core coordinated to six partially deprotonated [Fe(II)(bppCOOH)(bppCOO)](+) complexes. Raman spectroscopy studies on single crystals of 1 and 2 have been performed to elucidate the spin and oxidation states of iron in 2. These studies and magnetic characterization indicate that most of the iron(II) complexes of 2 remain in the low-spin (LS) state and present a gradual and incomplete spin crossover above 300 K. On the other hand, the Fe(III) trimer shows the expected antiferromagnetic behavior. From the structural point of view, 2 represents the first example in which bppCOO(-) acts as a bridging ligand, thus forming a polynuclear magnetic complex.

Allegheny County-Owned Bridges Points

Data.gov (United States)

Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset shows the location of bridges owned by Allegheny County as centroids. If viewing this description on the Western Pennsylvania Regional Data Center’s...

A new oxidimetric reagent: potassium dichromate in a strong phosphoric acid medium--VII. Photometric titration of vanadium(IV) and of cerium(III) alone and in mixtures with iroN(II).

Science.gov (United States)

Rao, G G; Rao, P K

1967-01-01

Vanadium(IV) can be accurately titrated with potassium dichromate in media containing phosphoric acid of 3-12M concentration: the change in absorption of vanadium(IV) is followed in the region 660 mmicro using a red filter. It is more convenient to carry out the titration in 3M phosphoric acid because at higher concentrations chloride, nitrate, cerium(III) and manganese(II) may interfere. Photoelcetric titration is more convenient than potentiometric because the former can be made in a 3M phosphoric acid medium, whereas the latter is possible only in 12M phosphoric acid. The simultaneous differential photometric titration of iron(II) and vanadium(IV) is also possible. Conditions have been found for the photometric titration of cerium(III) and of cerium(III) plus iron(II). The titration is carried out (at 450 mmicro or with a blue filter) in about 10.5M phosphoric acid. Application of the method to a cerium mineral is considered.

Chichibu park bridge, a Japan's longest PC cable suspension bridge that attaches importance to scenery. Keikan wo jushishita Nippon saidai no PC shachokyo 'Chichibu koenkyo'

Energy Technology Data Exchange (ETDEWEB)

1993-12-01

This paper introduces the feature of Chichibu Park Bridge, a Japan's longest PC cable suspension bridge that attaches importance to scenery. The maximum effective span of Chichibu Park Bridge which is a two-span continuous PC cable suspension bridge measures 195 m, that means the center span length is equivalent to about 400 m if converted to a three-span structure. With respect to the design that values the scenic effect, the main tower has relief engravings of stone carving tone using Chichibu Night Festival as a motif disposed around it; lighting up is applied to the main tower to highlight it so that it can be viewed from far away places; and a balcony is built on the center of the bridge. Chichibu Park Bridge has the bridge axial direction stagger with the river flow direction at 45[degree] to reduce water resistance. The tensile force generated at the corbel section according to the main tower reactive force is dealt with reinforced concrete rather than with prestressed concrete. The main tower adopts a two-chamber girder structure as its cross section shape from the view points of rigidity assurance and scenic effect. For construction control, micro computers are used to correct growing change in bend of the main girder due to temperature change and cable tension change. 6 figs., 4 tabs.

Determination of plutonium by secondary coulometric titration with internally generated iron(II) Pt. 2

International Nuclear Information System (INIS)

Chitnis, R.T.; Talnikar, S.G.; Thakur, V.A.; Paranjape, A.H.

1979-01-01

Determination of plutonium by secondary coulometry involving the controlled potential technique for the generation of an iron(II) mediator, is reported in Part I. In this paper, the same determination is reported using constant current coulometry for the generation of the mediator, and zero current potentiometry for end-point detection. The factors affecting the current efficiency, viz. current density and supporting electrolyte composition have been checked in order to define the appropriate conditions for obtaining 100% current efficiency. The original method of Carson et al. suffers from the disadvantage that it involves complicated sample treatment. Introduction of perchloric acid treatment as a method for the oxidation of plutonium and the pretitration of the supporting electrolyte to the end-point potential prior to sample addition, have considerably helped to improve the precision and accuracy of the method. Exhaustive analytical data are reported covering plutonium quantities ranging from 25 micrograms to 5 milligrams, which establishes the scope of the method. (author)

Integrated system of structural health monitoring and intelligent management for a cable-stayed bridge.

Science.gov (United States)

Chen, Bin; Wang, Xu; Sun, Dezhang; Xie, Xu

2014-01-01

It is essential to construct structural health monitoring systems for large important bridges. Zhijiang Bridge is a cable-stayed bridge that was built recently over the Hangzhou Qiantang River (the largest river in Zhejiang Province). The length of Zhijiang Bridge is 478 m, which comprises an arched twin-tower space and a twin-cable plane structure. As an example, the present study describes the integrated system of structural health monitoring and intelligent management for Zhijiang Bridge, which comprises an information acquisition system, data management system, evaluation and decision-making system, and application service system. The monitoring components include the working environment of the bridge and various factors that affect bridge safety, such as the stress and strain of the main bridge structure, vibration, cable force, temperature, and wind speed. In addition, the integrated system includes a forecasting and decision-making module for real-time online evaluation, which provides warnings and makes decisions based on the monitoring information. From this, the monitoring information, evaluation results, maintenance decisions, and warning information can be input simultaneously into the bridge monitoring center and traffic emergency center to share the monitoring data, thereby facilitating evaluations and decision making using the system.

A model study of bridge hydraulics

Science.gov (United States)

2010-08-01

Most flood studies in the United States use the Army Corps of Engineers HEC-RAS (Hydrologic Engineering : Centers River Analysis System) computer program. This study was carried out to compare results of HEC-RAS : bridge modeling with laboratory e...

Manganese(II), iron(II), and mixed-metal metal-organic frameworks based on chains with mixed carboxylate and azide bridges: magnetic coupling and slow relaxation.

Science.gov (United States)

Wang, Yan-Qin; Yue, Qi; Qi, Yan; Wang, Kun; Sun, Qian; Gao, En-Qing

2013-04-15

Mn(II) and Fe(II) compounds derived from azide and the zwitterionic 1-carboxylatomethylpyridinium-4-carboxylate ligand are isomorphous three-dimensional metal-organic frameworks (MOFs) with the sra net, in which the metal ions are connected into anionic chains by mixed (μ-1,1-azide)bis(μ-carboxylate) triple bridges and the chains are cross-linked by the cationic backbones of the zwitterionic ligands. The Mn(II) MOFs display typical one-dimensional antiferromagnetic behavior. In contrast, with one more d electron per metal center, the Fe(II) counterpart shows intrachain ferromagnetic interactions and slow relaxation of magnetization attributable to the single-chain components. The activation energies for magnetization reversal in the infinite- and finite-chain regimes are Δτ1 = 154 K and Δτ2 = 124 K, respectively. Taking advantage of the isomorphism between the Mn(II) and Fe(II) MOFs, we have prepared a series of mixed-metal Mn(II)(1-x)Fe(II)(x) MOFs with x = 0.41, 0.63, and 0.76, which intrinsically feature random isotropic/anisotropic sites and competing antiferromagnetic-ferromagnetic interactions. The materials show a gradual antiferromagnetic-to-ferromagnetic evolution in overall behaviors as the Fe(II) content increases, and the Fe-rich materials show complex relaxation processes that may arise for mixed SCM and spin-glass mechanisms. A general trend is that the activation energy and the blocking temperature increase with the Fe(II) content, emphasizing the importance of anisotropy for slow relaxation of magnetization.

A diketiminate-bound diiron complex with a bridging carbonate ligand

Science.gov (United States)

Sadique, Azwana R.; Brennessel, William W.; Holland, Patrick L.

2009-01-01

Reduction of carbon dioxide by a diiron(I) complex gives μ-carbonato-κ3 O:O′,O′′-bis­{[2,2,6,6-tetra­methyl-3,5-bis­(2,4,6-triisopropyl­phenyl)heptane-2,5-diiminate(1−)-κ2 N,N′]iron(II)} toluene disolvate, [Fe2(C41H65N)2(CO3)]·2C7H8, a diiron(II) species with a bridging carbonate ligand. The asymmetric unit contains one diiron complex and two cocrystallized toluene solvent mol­ecules that are distributed over three sites, one with atoms in general positions and two in crystallographic sites. Both FeII atoms are η2-coordinated to diketiminate ligands, but η1- and η2-coordinated to the bridging carbonate ligand. Thus, one FeII center is three-coordinate and the other is four-coordinate. The bridging carbonate ligand is nearly perpendicular to the iron–diketiminate plane of the four-coordinate FeII center and parallel to the plane of the three-coordinate FeII center. PMID:19407402

Effects of Irregular Bridge Columns and Feasibility of Seismic Regularity

Science.gov (United States)

Thomas, Abey E.

2018-05-01

Bridges with unequal column height is one of the main irregularities in bridge design particularly while negotiating steep valleys, making the bridges vulnerable to seismic action. The desirable behaviour of bridge columns towards seismic loading is that, they should perform in a regular fashion, i.e. the capacity of each column should be utilized evenly. But, this type of behaviour is often missing when the column heights are unequal along the length of the bridge, allowing short columns to bear the maximum lateral load. In the present study, the effects of unequal column height on the global seismic performance of bridges are studied using pushover analysis. Codes such as CalTrans (Engineering service center, earthquake engineering branch, 2013) and EC-8 (EN 1998-2: design of structures for earthquake resistance. Part 2: bridges, European Committee for Standardization, Brussels, 2005) suggests seismic regularity criterion for achieving regular seismic performance level at all the bridge columns. The feasibility of adopting these seismic regularity criterions along with those mentioned in literatures will be assessed for bridges designed as per the Indian Standards in the present study.

Integrated System of Structural Health Monitoring and Intelligent Management for a Cable-Stayed Bridge

Directory of Open Access Journals (Sweden)

Bin Chen

2014-01-01

Full Text Available It is essential to construct structural health monitoring systems for large important bridges. Zhijiang Bridge is a cable-stayed bridge that was built recently over the Hangzhou Qiantang River (the largest river in Zhejiang Province. The length of Zhijiang Bridge is 478 m, which comprises an arched twin-tower space and a twin-cable plane structure. As an example, the present study describes the integrated system of structural health monitoring and intelligent management for Zhijiang Bridge, which comprises an information acquisition system, data management system, evaluation and decision-making system, and application service system. The monitoring components include the working environment of the bridge and various factors that affect bridge safety, such as the stress and strain of the main bridge structure, vibration, cable force, temperature, and wind speed. In addition, the integrated system includes a forecasting and decision-making module for real-time online evaluation, which provides warnings and makes decisions based on the monitoring information. From this, the monitoring information, evaluation results, maintenance decisions, and warning information can be input simultaneously into the bridge monitoring center and traffic emergency center to share the monitoring data, thereby facilitating evaluations and decision making using the system.

Sunshine Skyway Bridge monitoring phase I : system assessment and integration recommendations [summary].

Science.gov (United States)

2016-10-01

At over five miles long, the Sunshine Skyway Bridge, crossing Tampa Bay where it meets the Gulf of Mexico, is one of the worlds longest cable-stayed bridges. The pier-supported approaches rise to meet the center section where cables radiating from...

Dynamic response of a monorail steel bridge under a moving train

Science.gov (United States)

Lee, C. H.; Kawatani, M.; Kim, C. W.; Nishimura, N.; Kobayashi, Y.

2006-06-01

This study proposes a dynamic response analysis procedure for traffic-induced vibration of a monorail bridge and train. Each car in the monorail train is idealized as a dynamic system of 15-degrees-of-freedom. The governing equations of motion for a three-dimensional monorail bridge-train interaction system are derived using Lagrange's formulation for monorail trains, and a finite-element method for modal analysis of monorail bridges. Analytical results on dynamic response of the monorail train and bridge are compared with field-test data in order to verify the validity of the proposed analysis procedure, and a positive correlation is found. An interesting feature of the monorail bridge response is that sway motion is caused by torsional behavior resulting from eccentricity between the shear center of the bridge section and the train load.

Project LOCAL - Bridging The Gap

Science.gov (United States)

Haven, Robert N.

1975-01-01

Project LOCAL, a not-for-profit regional consortium, offers a broad spectrum of in-service training courses tailored to meet the needs of educators in various disciplines and levels of experience. The purpose of these offerings is to bridge the communication gap between innovative centers in computer-oriented education and staff members in Boston…

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

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Bridge-to-Bridge Act § 80.1007 Bridge-to-bridge radiotelephone installation. Use of the bridge-to-bridge...

Electrical Actuation Technology Bridging

Science.gov (United States)

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

1993-01-01

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

Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

KAUST Repository

Haslinger, Stefan

2014-11-03

This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

Making oxidation potentials predictable: Coordination of additives applied to the electronic fine tuning of an iron(II) complex

KAUST Repository

Haslinger, Stefan; Kü ck, Jens W.; Hahn, Eva M.; Cokoja, Mirza; Pö thig, Alexander; Basset, Jean-Marie; Kü hn, Fritz

2014-01-01

This work examines the impact of axially coordinating additives on the electronic structure of a bioinspired octahedral low-spin iron(II) N-heterocyclic carbene (Fe-NHC) complex. Bearing two labile trans-acetonitrile ligands, the Fe-NHC complex, which is also an excellent oxidation catalyst, is prone to axial ligand exchange. Phosphine- and pyridine-based additives are used for substitution of the acetonitrile ligands. On the basis of the resulting defined complexes, predictability of the oxidation potentials is demonstrated, based on a correlation between cyclic voltammetry experiments and density functional theory calculated molecular orbital energies. Fundamental insights into changes of the electronic properties upon axial ligand exchange and the impact on related attributes will finally lead to target-oriented manipulation of the electronic properties and consequently to the effective tuning of the reactivity of bioinspired systems.

Extracorporeal membrane oxygenation as a bridge to lung transplantation: A single-center experience in the present era.

Science.gov (United States)

Todd, Emily M; Biswas Roy, Sreeja; Hashimi, A Samad; Serrone, Rosemarie; Panchanathan, Roshan; Kang, Paul; Varsch, Katherine E; Steinbock, Barry E; Huang, Jasmine; Omar, Ashraf; Patel, Vipul; Walia, Rajat; Smith, Michael A; Bremner, Ross M

2017-11-01

Extracorporeal membrane oxygenation has been used as a bridge to lung transplantation in patients with rapid pulmonary function deterioration. The reported success of this modality and perioperative and functional outcomes are varied. We retrospectively reviewed all patients who underwent lung transplantation at our institution over 1 year (January 1, 2015, to December 31, 2015). Patients were divided into 2 groups depending on whether they required extracorporeal membrane oxygenation support as a bridge to transplant; preoperative characteristics, lung transplantation outcomes, and survival were compared between groups. Of the 93 patients, 12 (13%) received bridge to transplant, and 81 (87%) did not. Patients receiving bridge to transplant were younger, had higher lung allocation scores, had lower functional status, and were more often on mechanical ventilation at listing. Most patients who received bridge to transplant (n = 10, 83.3%) had pulmonary fibrosis. Mean pretransplant extracorporeal membrane oxygenation support was 103.6 hours in duration (range, 16-395 hours). All patients who received bridge to transplant were decannulated immediately after lung transplantation but were more likely to return to the operating room for secondary chest closure or rethoracotomy. Grade 3 primary graft dysfunction within 72 hours was similar between groups. Lung transplantation success and hospital discharge were 100% in the bridge to transplant group; however, these patients experienced longer hospital stays and higher rates of discharge to acute rehabilitation. The 1-year survival was 100% in the bridge to transplant group and 91% in the non-bridge to transplant group (log-rank, P = .24). The 1-year functional status was excellent in both groups. Extracorporeal membrane oxygenation can be used to safely bridge high-acuity patients with end-stage lung disease to lung transplantation with good 30-day, 90-day, and 1-year survival and excellent 1-year functional status

47 CFR 80.331 - Bridge-to-bridge communication procedure.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge communication procedure. 80..., Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a) Vessels subject to the Bridge-to-Bridge Act transmitting on the designated navigational frequency must conduct...

Spectrum of OH-stretching vibrations of water in a "floating" water bridge

Science.gov (United States)

Oshurko, V. B.; Ropyanoi, A. A.; Fedorov, A. N.; Fedosov, M. V.; Shelaeva, N. A.

2012-11-01

The axial distribution (over the cross section) of the spectra of the OH-stretching band of water in a water bridge is investigated using the Raman scattering method. It is found that the axial structure of the bridge is inhomogeneous: the core at the center of the bridge contains a larger amount of water with an "icelike" structure and a presumably larger number of H+ ions, while the outer layer probably consists of water with a larger number of OH- ions.

Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

Energy Technology Data Exchange (ETDEWEB)

Chintakunta, Satish R. [Engineering and Software Consultants, Inc., 14123 Robert Paris Ct., Chantilly, VA 20151 (United States); Boone, Shane D. [Federal Highway Administration, Turner Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101 (United States)

2014-02-18

Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

Science.gov (United States)

Chintakunta, Satish R.; Boone, Shane D.

2014-02-01

Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

Bridge Approach Remedies Implemented at Western Mega Site

Science.gov (United States)

2017-09-01

As part of the heavy axle load (HAL) revenue service mega site testing program, the Transportation Technology Center, Inc. (TTCI) has worked closely with the Union Pacific Railroad (UP) to address bridge approach problems under HAL operations. The te...

Determination of plutonium in nitric acid solutions - Method by oxidation by cerium(IV), reduction by iron(II) ammonium sulfate and amperometric back-titration with potassium dichromate

International Nuclear Information System (INIS)

1987-01-01

This International Standard specifies a precise and accurate analytical method for determining plutonium in nitric acid solutions. Plutonium is oxidized to plutonium(VI) in a 1 mol/l nitric acid solution with cerium(IV). Addition of sulfamic acid prevents nitrite-induced side reactions. The excess of cerium(IV) is reduced by adding a sodium arsenite solution, catalysed by osmium tetroxide. A slight excess of arsenite is oxidized by adding a 0.2 mol/l potassium permanganate solution. The excess of permanganate is reduced by adding a 0.1 mol/l oxalic acid solution. Iron(III) is used to catalyse the reduction. A small excess of oxalic acid does not interfere in the subsequent plutonium determination. These reduction and oxidation stages can be followed amperometrically and the plutonium is left in the hexavalent state. The sulfuric acid followed by a measured amount of standardized iron(II) ammonium sulfate solution in excess of that required to reduce the plutonium(VI) to plutonium(IV) is added. The excess iron(II) and any plutonium(III) formed to produce iron(III) and plutonium(IV) is amperometrically back-titrated using a standard potassium dichromate solution. The method is almost specifically for plutonium. It is suitable for the direct determination of plutonium in materials ranging from pure product solutions, to fast reactor fuel solutions with a uranium/plutonium ratio of up to 10:1, either before or after irradiation

Combined biotin-terpyridine systems : a new versatile bridge between biology, polymer science and metallo-supramolecular chemistry

NARCIS (Netherlands)

Hofmeier, H.; Pahnke, J.; Weidl, C.H.; Schubert, U.S.

2004-01-01

Biotin, a well-known binding unit for the proteins avidin and streptavidin, was combined with the chelating ligand terpyridine via polymeric and nonpolymeric spacers. An ¿-amino-functionalized terpyridyl-poly(ethylene glycol) was prepared and utilized for complex formation with iron(II), nickel(II),

Iron(II) phthalocyanine covalently functionalized graphene as a highly efficient non-precious-metal catalyst for the oxygen reduction reaction in alkaline media

International Nuclear Information System (INIS)

Liu, Ying; Wu, Yan-Ying; Lv, Guo-Jun; Pu, Tao; He, Xing-Quan; Cui, Li-Li

2013-01-01

Graphical abstract: The fabricated FePc-Gr catalyst for ORR exhibited high activity, favoring a direct 4-electron process, good stability and selectivity, all of which should be attributed to its high conductivity, the synergistic effect between FePc and graphene, as well as the formation of stable FePc-Gr composite through covalent bonding and π–π interaction. - Abstract: A novel iron(II) phthalocyanine covalently modified graphene (FePc-Gr) was synthesized by reduction of the product obtained through an amidation reaction between carboxyl-functionalized graphene oxide (CFGO) and iron(II) tetra-aminophthalocyanine (FeTAPc). The FePc-Gr hybird was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS), respectively. The electrocatalytic properties of FePc-Gr toward the oxygen reduction reaction (ORR) were evaluated using cyclic voltammetry (CV) and linear sweep voltammetry methods. The peak potential of the ORR on the FePc-Gr catalyst was found to be about −0.12 V vs. SCE in 0.1 M NaOH solution, which was 180 and 360 mV more positive than that on FeTAPc and bare GCE, respectively. The rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) measurements revealed that the ORR mechanism was nearly via a direct four-electron pathway to water on FePc-Gr. The current still remained 83.5% of its initial after chronoamperometric test for 10,000 s. Nevertheless, Pt/C catalyst only retained 40.5% of its initial current. The peak potential and peak current changed slightly when 3 M methanol was introduced. So the FePc-Gr composite catalyst for ORR exhibited high activity, good stability and methanol-tolerance, which could be used as a promising Pt-free catalyst for ORR in alkaline direct methanol fuel cell (DMFC)

Synthesis and Ligand Non-Innocence of Thiolate-Ligated (N4S) Iron(II) and Nickel(II) Bis(imino)pyridine Complexes

Science.gov (United States)

Widger, Leland R.; Jiang, Yunbo; Siegler, Maxime; Kumar, Devesh; Latifi, Reza; de Visser, Sam P.; Jameson, Guy N.L.; Goldberg, David P.

2013-01-01

The known iron(II) complex [FeII(LN3S)(OTf)] (1) was used as starting material to prepare the new biomimetic (N4S(thiolate)) iron(II) complexes [FeII(LN3S)(py)](OTf) (2) and [FeII(LN3S)(DMAP)](OTf) (3), where LN3S is a tetradentate bis(imino)pyridine (BIP) derivative with a covalently tethered phenylthiolate donor. These complexes were characterized by X-ray crystallography, UV-vis, 1H NMR, and Mössbauer spectroscopy, as well as electrochemistry. A nickel(II) analogue, [NiII(LN3S)](BF4) (5), was also synthesized and characterized by structural and spectroscopic methods. Cyclic voltammetric studies showed 1 – 3 and 5 undergo a single reduction process with E1/2 between −0.9 to −1.2 V versus Fc+/Fc. Treatment of 3 with 0.5% Na/Hg amalgam gave the mono-reduced complex [Fe(LN3S)(DMAP)]0 (4), which was characterized by X-ray crystallography, UV-vis, EPR (g = [2.155, 2.057, 2.038]) and Mössbauer (δ = 0.33 mm s−1; ΔEQ = 2.04 mm s−1) spectroscopies. Computational methods (DFT) were employed to model complexes 3 – 5. The combined experimental and computational studies show that 1 – 3 are 5-coordinate, high-spin (S = 2) FeII complexes, whereas 4 is best described as a 5-coordinate, intermediate-spin (S = 1) FeII complex antiferromagnetically coupled to a ligand radical. This unique electronic configuration leads to an overall doublet spin (Stotal = ½) ground state. Complexes 2 and 3 are shown to react with O2 to give S-oxygenated products, as previously reported for 1. In contrast, the mono-reduced 4 appears to react with O2 to give a mixture of S- and Fe-oxygenates. The nickel(II) complex 5 does not react with O2, and even when the mono-reduced nickel complex is produced, it appears to undergo only outer-sphere oxidation with O2. PMID:23992096

Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

KAUST Repository

Chinnusamy, Tamilselvi R.

2012-05-09

The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Construction of the Chamagawa bridge; Chamagawabashi no seko

Energy Technology Data Exchange (ETDEWEB)

Kawado, A.; Okawa, M. [Honshu-Shikoku Bridge Authority, Tokyo (Japan); Yoshii, M.; Oda, I.

1997-09-30

The Chamagawa Bridge is a reinforced concrete fixed-arch bridge which is located at the northern end of Awaji Island, 1.5 km away from the Honshu-Shikoku linking large-scale Akashi Strait Bridge. This paper describes the design and construction of the bridge. Overhang construction method using cable stayed members was adopted. Against the tensile stress generated in the arch-ring under construction, reaction force was burdened with cable stayed columns, anchor blocks and ground anchors by regulating stress using cable stayed members and by resisting using PC steel rods arranging in the arch-ring. For the construction of arch-ring, a space was made for fabricating a specific large-scale movable working vehicle by the grounding support. Then, overhang construction was started. For the construction of overhang, construction of cable stayed members, regulation of stress, and tension of ground anchors were conducted with the construction of each block. The construction of linking block in the center was conducted by hanging support method after the specific large-scale movable working vehicle was taken to pieces. After the connection of arch-ring, tensile forces of cable stayed members and ground anchors were released. The bridge was completed in the down road in 1997. 1 ref., 21 figs., 6 tabs.

Iron phthalocyanine supported on amidoximated PAN fiber as effective catalyst for controllable hydrogen peroxide activation in oxidizing organic dyes

International Nuclear Information System (INIS)

Han, Zhenbang; Han, Xu; Zhao, Xiaoming; Yu, Jiantao; Xu, Hang

2016-01-01

Iron(II) phthalocyanine was immobilized onto amidoximated polyacrylonitrile fiber to construct a bioinspired catalytic system for oxidizing organic dyes by H 2 O 2 activation. The amidoxime groups greatly helped to anchor Iron(II) phthalocyanine molecules onto the fiber through coordination interaction, which has been confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and UV diffuse reflectance spectroscopy analyses. Electron spin resonance studies indicate that the catalytic process of physically anchored Iron(II) phthalocyanine performed via a hydroxyl radical pathway, while the catalyst bonded Iron(II) phthalocyanine through coordination effect could selectively catalyze the H 2 O 2 decomposition to generate high-valent iron-oxo species. This may result from the amidoxime groups functioning as the axial fifth ligands to favor the heterolytic cleavage of the peroxide O−O bond. This feature also enables the catalyst to only degrade the dyes adjacent to the catalytic active centers and enhances the efficient utilization of H 2 O 2 . In addition, this catalyst could effectively catalyze the mineralization of organic dyes and can be easily recycled without any loss of activity.

The Akashi Kaikyo Bridge and the Storebælt Bridge

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

Bridge Management Systems

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

Synthesis, characterization and single crystal x-ray analysis of a complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine

Energy Technology Data Exchange (ETDEWEB)

Kumar, Sandeep; Andotra, Savit; Kaur, Mandeep [University of Jammu, Department of Chemistry (India); Gupta, Vivek K.; Kant, Rajni [Department of Physics and Electronics, University of Jammu, X-ray Crystallographic Laboratory (India); Pandey, Sushil K., E-mail: kpsushil@rediffmail.com [University of Jammu, Department of Chemistry (India)

2016-09-15

Complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine [((2,4- (CH{sub 3}){sub 2}C{sub 6}H{sub 3}O)2PS2)2Fe(NC{sub 5}H{sub 4}(C{sub 2}H{sub 5})-4){sub 2}] is synthesized and characterized by elemental analysis, magnetic moment, IR spectroscopy and single crystal X-ray analysis. Complex crystallizes in the monoclinic sp. gr. P2{sub 1}/n, Z = 2. Crystal structure consists of mononuclear units with Fe(II) ion chelated by four S atoms of the two diphenyldithiophosphate ligands in bidentate manner. N atoms from two 4-ethylpyridine ligands are axially coordinated to the Fe(II) atom leading to an octahedral geometry.

Performance of Rail Fastening Systems on an Open-Deck Bridge

Science.gov (United States)

2018-02-01

Transportation Technology Center, Inc. (TTCI) monitored the performance of rail fasteners on an open-deck bridge and its approaches, located at Norfolk Southern Corporations (NS's) eastern mega site. The project was co-sponsored by the Federal Rai...

Railroad Bridges

Data.gov (United States)

Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

Implementation of Bridge Management System on Interurban Bridge in Maluku Province

Directory of Open Access Journals (Sweden)

Erwin Marasabessy

2015-05-01

Full Text Available Bridges as transport infrastructures play a vital role in smoothing traffic flows. The success of a bridge in playing its role and serving its function depends on its management. The Directorate General of Highways of the Ministry of Public Work has used a system to manage bridges known as the Bridge Management System (BMS. The system allows a systematic plan and provides a uniform procedure for all bridge operation activities on the national and provincial level. Data from Implementation Agency of National Inter-Urban Roads of Area IX, Northern Maluku in 2011 indicates that the total length of national roads in Maluku Province is 15,238.01 M, with a total of 562 bridges. In Ambon Island, especially, there are 52 bridges totaling 1,176.25 m in length. The study was conducted at several inter-urban bridges in Maluku Province of Ambon Island: Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari and Wai Tua bridges. Assessment of bridge structure conditions was conducted visually to determine the conditions of the existing bridges comprehensively by referring to the Bridge Management System (BMS complemented with a computer-based Bridge Management Information System (BMIS. Condition scores for the five bridges—Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua, according to Bridge Management System, are 2, 1, 2, 1, and 2 respectively. The scores of the five bridges indicate that their physical condition can be categorized as good or with minor defects. Based on technical screening, the proposed treatment for Wai Batu Merah, Wai Ruhu, Wai Lawa, dan Wai Tua bridges is the rehabilitation of their sub-elements. As for the Wai Yari Bridge, the treatment will be maintained regularly. The defect repair costs are IDR 149,138,238.00, IDR 81,048,000.00, IDR 174,579,106.10, IDR 79,233,324.01 and IDR 238,323,258.60 for Wai Batu, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua Bridges, respectively.

Multisensor system for determination of iron(II), iron(III), uranium(VI) and uranium(IV) in complex solutions

International Nuclear Information System (INIS)

Legin, A.V.; Seleznev, B.L.; Rudnitskaya, A.M.; Vlasov, Yu.G.; Tverdokhlebov, S.V.; Mack, B.; Abraham, A.; Arnold, T.; Baraniak, L.; Nitsche, H.

1999-01-01

Development and analytical evaluation of a multisensor system based on the principles of 'electronic tongue' for the determination of low contents of uranium(VI), uranium(IV), iron(II) and iron(III) in complex aqueous media have been carried out. A set of 29 different chemical sensors on the basis of all- solid-state crystalline and vitreous materials with enhanced electronic conductivity and redox and ionic cross-sensitivity have been incorporated into the sensor array. Multidimensional data have been processed by pattern recognition methods such as artificial neural networks and partial least squares. It has been demonstrated that Fe(II) and Fe(III) contents in the range from 10 -7 to 10 -4 mol L -1 of total iron concentration can be determined with the average precision of about 25 %. U(VI) and U(IV) contents can been determined with the average precision of 10-40% depending on the concentration. The developed multisensor system can be applied in future for the analysis of mining and borehole waters as well other contaminated natural media, including on-site measurements. (author)

Bridging Implementation, Knowledge, and Ambition Gaps to Eliminate Tuberculosis

Centers for Disease Control (CDC) Podcasts

2011-02-22

In this podcast, Dr. Kenneth Castro, director of CDC's Division of Tuberculosis Eliminatio,discusses bridging implementation, knowledge, and ambition gaps to eliminate tuberculosis.  Created: 2/22/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 3/2/2011.

Long-term bridge performance high priority bridge performance issues.

Science.gov (United States)

2014-10-01

Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

Multistep Oxidation of Diethynyl Oligophenylamine-Bridged Diruthenium and Diiron Complexes.

Science.gov (United States)

Zhang, Jing; Guo, Shen-Zhen; Dong, Yu-Bao; Rao, Li; Yin, Jun; Yu, Guang-Ao; Hartl, František; Liu, Sheng Hua

2017-01-17

Homo-dinuclear nonlinear complexes [{M(dppe)Cp*} 2 {μ-(-C≡C) 2 X}] (dppe = 1,2-bis(diphenylphosphino)ethane; Cp* = η 5 -C 5 Me 5 ; X = triphenylamine (TPA), M = Ru (1a) and Fe (1b); X = N,N,N',N'-tetraphenylphenylene-1,4-diamine (TPPD), M = Ru (2a)) were prepared and characterized by 1 H, 13 C, and 31 P NMR spectroscopy and single-crystal X-ray diffraction (1a, 2a). Attempts to prepare the diiron analogue of 2a were not successful. Experimental data obtained from cyclic voltammetry, square wave voltammetry, UV-vis-NIR (NIR = near-infrared) spectro-electrochemistry, and very informative IR spectro-electrochemistry in the C≡C stretching region, combined with density functional theory calculations, afford to make an emphasizing assessment of the close association between the metal-ethynyl termini and the oligophenylamine bridge core as well as their respective involvement in sequential one-electron oxidations of these complexes. The anodic behavior of the homo-bimetallic complexes depends strongly both on the metal center and the length of the oligophenylamine bridge core. The poorly separated first two oxidations of diiron complex 1b are localized on the electronically nearly independent Fe termini. In contrast, diruthenium complex 1a exhibits a significantly delocalized character and a marked electronic communication between the ruthenium centers through the diethynyl-TPA bridge. The ruthenium-ethynyl halves in 2a, separated by the doubly extended and more flexible TPPD bridge core, show a lower degree of electronic coupling, resulting in close-lying first two anodic waves and the NIR electronic absorption of [2a] + with an indistinctive intervalence charge transfer character. Finally, the third anodic waves in the voltammetric responses of the homo-bimetallic complexes are associated with the concurrent exclusive oxidation of the TPA or TPPD bridge cores.

47 CFR 80.163 - Operator requirements of the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operator requirements of the Bridge-to-Bridge... Requirements § 80.163 Operator requirements of the Bridge-to-Bridge Act. Each ship subject to the Bridge-to-Bridge Act must have on board a radio operator who holds a restricted radiotelephone operator permit or...

Phosphorescent heterobimetallic complexes involving platinum(iv) and rhenium(vii) centers connected by an unsupported μ-oxido bridge.

Science.gov (United States)

Molaee, Hajar; Nabavizadeh, S Masoud; Jamshidi, Mahboubeh; Vilsmeier, Max; Pfitzner, Arno; Samandar Sangari, Mozhgan

2017-11-28

Heterobimetallic compounds [(C^N)LMe 2 Pt(μ-O)ReO 3 ] (C^N = ppy, L = PPh 3 , 2a; C^N = ppy, L = PMePh 2 , 2b; C^N = bhq, L = PPh 3 , 2c; C^N = bhq, L = PMePh 2 , 2d) containing a discrete unsupported Pt(iv)-O-Re(vii) bridge have been synthesized through a targeted synthesis route. The compounds have been prepared by a single-pot synthesis in which the Pt(iv) precursor [PtMe 2 I(C^N)L] complexes are allowed to react easily with AgReO 4 in which the iodide ligand of the starting Pt(iv) complex is replaced by an ReO 4 - anion. In these Pt-O-Re complexes, the Pt(iv) centers have an octahedral geometry, completed by a cyclometalated bidentate ligand (C^N), two methyl groups and a phosphine ligand, while the Re(vii) centers have a tetrahedral geometry. Elemental analysis, single crystal X-ray diffraction analysis and multinuclear NMR spectroscopy are used to establish their identities. The new complexes exhibit phosphorescence emission in the solid and solution states at 298 and 77 K, which is an uncommon property of platinum complexes with an oxidation state of +4. According to DFT calculations, we found that this emission behavior in the new complexes originates from ligand centered 3 LC (C^N) character with a slight amount of metal to ligand charge transfer ( 3 MLCT). The solid-state emission data of the corresponding cycloplatinated(iv) precursor complexes [PtMe 2 I(C^N)L], 1a-1d, pointed out that the replacement of I - by an ReO 4 - anion helps enhancing the emission efficiency besides shifting the emission wavelengths.

Cable-stayed bridge No. 1 Hikihara bridge'' ( Karauko bridge'') for Kinki construction bureau, ministry of construction. Kensetsusho kinki chiho kensetsukyoku (Hikihara 1 gobashi (Karauko ohashi))no shiko

Energy Technology Data Exchange (ETDEWEB)

1991-11-01

This paper summarizes the design, fabrication and erection of a back-anchor integrated single span cable suspension bridge (178 m long and 9.7 m wide) constructed over an ordinary road crossing a reservoir. This type of structure was adopted because the locational condition does not allow a bridge pier to be erected in the center of the pond, and the topography in the construction starting side has steep slopes and many places having fragile ground beds. This bridge employed precast floor plates using the Compo-Slab (manufactured by Ishikawajima Building Material Company). Main points which require attentions are listed in designing and fabricating the main towers (48 m high), main girders, and cables, as well as fabricating the precast cast floor plates (a panel has a length of 9.7 m, maximum width of 2 m, and maximum weight of 10 tons). The main towers were erected using 160-tf truck cranes, and the main girders were erected by the overhang method using 20-tf gate-type travel cranes. 3 refs., 14 figs.

Bridge health monitoring metrics : updating the bridge deficiency algorithm.

Science.gov (United States)

2009-10-01

As part of its bridge management system, the Alabama Department of Transportation (ALDOT) must decide how best to spend its bridge replacement funds. In making these decisions, ALDOT managers currently use a deficiency algorithm to rank bridges that ...

47 CFR 80.309 - Watch required by the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Watch required by the Bridge-to-Bridge Act. 80... Safety Watches § 80.309 Watch required by the Bridge-to-Bridge Act. In addition to the watch requirement contained in § 80.148, all vessels subject to the Bridge-to-Bridge Act must keep a watch on the designated...

Study on the structural characteristics of extradosed concrete bridges; Ekusutoradozudo kyo no kozo tokusei ni kansuru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Oka, Y. [Japan Highway Public Corp., Tokyo (Japan); Kasuga, A. [Sumitomo Construction Co. Ltd., Tokyo (Japan); Yamazaki, J. [Nihon Univ., Tokyo (Japan). Coll. of Science and Engineering

1997-03-31

Parameters are analyzed to provide data for deciding, in the planning and designing stages, whether a cable stayed bridge or an extradosed bridge should be adopted. Comparative investigation of the vibration properties of both types of bridges is also referred to. The result of the study on the structural properties of the cable stayed road bridge and the extradosed road bridge is introduced. Based on the concept of the extradosed bridge, designers are now able to select without restraint the after load sharing rate of the diagonal members. Parameter analysis of a diagonal member reinforced 3-span continuous beam is performed. By introducing indices showing the load sharing rate of the diagonal member, the cable stayed bridge can be distinguished logically from the extradosed bridge in designing. It is found important that the height of the main tower is set to approximately 10% the length of the center span for the construction of the extradosed bridge. The vibration properties of the cable stayed bridge and the extradosed bridge of the same scale are compared. 7 refs., 18 figs., 6 tabs.

Field performance of timber bridges. 7, Connell Lake stress-laminated deck bridge

Science.gov (United States)

L. E. Hislop; M. A. Ritter

The Connell Lake bridge was constructed in early 1991 on the Tongass National Forest, Alaska, as a demonstration bridge under the Timber Bridge Initiative. The bridge is a stress-laminated deck structure with an approximate 36-ft length and 18-ft width and is the first known stress-laminated timber bridge constructed in Alaska. Performance of the bridge was monitored...

Erection of the stiffening girder of the Akashi Kaikyo bridge; Akashi Kaikyo Ohashi hokoketa (sono 2) koji no genchi seko

Energy Technology Data Exchange (ETDEWEB)

Otsuki, M.; Inoue, M.; Ueno, Y.; Matsumura, T.; Oe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1998-12-20

The Akashi Kaikyo Bridge is 3,911m long with a center span of 1,991m, making it the longest suspension bridge in the world. Much careful attention has been given to the erection planning details in order to construct the bridge to withstand the harsh environmental conditions of that area. This report details the characteristics of the bridge stiffening girder and erection procedure, and the effects of the Hyogoken-Nanbu Earthquake. (author)

IceBridge NSERC L1B Geolocated Meteorologic and Surface Temperature Data

Data.gov (United States)

National Aeronautics and Space Administration — The IceBridge National Suborbital Education & Research Center (NSERC) L1B Geolocated Meteorologic and Surface Temperature (IAMET1B) data set is a collection of...

Track-Bridge Longitudinal Interaction of Continuous Welded Rails on Arch Bridge

Directory of Open Access Journals (Sweden)

Rong Chen

2013-01-01

Full Text Available Taking arch bridges, including deck, half-through, and through arch bridges (short for DAB, HTAB, and TAB as examples, mechanics analysis models of longitudinal interaction between continuously welded rails (short for CWRs and arch bridges are established. Based on the finite element method (FEM, the longitudinal interaction calculation software of CWR on arch bridges has been developed. Focusing on an HTAB, the tension, compression, and deflection conditions are calculated and analyzed. The results show that the mechanics analysis models of three types of arch bridges can truly reflect the real state of the structure; the calculation software can be used for systematic research of the CWR on arch bridge; as for HTAB, temperature difference of arch rib has a small effect on rail tension/compression, and arch bridge can be simplified as a continuous beam for rail tension/compression additional force calculation; in calculation of deflection conditions of HTAB, it is suggested that train loads are arranged on half span and full span and take the direction of load entering bridge into account. Additionally, the deflection additional force variation of CFST basket handle arch bridge is different from that of ordinary bridge.

Design and construction of PC cable-stayed bridge reducing the weight of dead load (Minamitabaru No. 1 Bridge). Shuko danmen no keiryoka wo hakatta PC shachokyo (kasho Minamitabaru 1 go kyo)

Energy Technology Data Exchange (ETDEWEB)

Otsuka, H. (Building Research Inst., Tokyo (Japan)); Ikari, K.; Ono, Y. (Ministry of Construction, Tokyo (Japan)); Hirano, A.

1993-03-15

The Minamitabaru No.1 bridge is a PC cable-stayed bridge with a 170m center span. The cross section dead load weight of the main beam in the center span is reduced to decrease the unbalance moment during construction and the negative reaction force after the completion. As a result, the average volume of concrete in the center span becomes 0.55m[sup 3]/m[sup 2] which is less by about 20% in comparison with a PC cable-stayed bridge of the similar scale. Separated 2 chamber box girder cross section is adopted for the shape of the main beam cross section to reduce the dead load weight of the cross section, and to improve the rigidity of the cross section and wind resisting stability, etc. In addition, a cross beam is provided in the diagonal member anchorage position to integrate the two box beams. A wind tunnel test is performed using a 1/30 scale model to confirm the wind resisting stability. The diagonal member is structured with several PC steel members. At the same time, a stretching work carriage is developed and used which can establish 3 dimensional position and direction by a hydraulic jack. 7 figs.

Consideration on extradosed prestressed concrete road bridge; Dorokyo ni okeru daihenshin PC keburu kyo

Energy Technology Data Exchange (ETDEWEB)

Ogawa, A.; Honma, A. [Japan Highway Public Corp., Tokyo (Japan)

1997-03-31

The details of the investigation on the Odawara Blue Way Bridge for which extradosed type is employed are provided, and a report is made about the situation of the study on the future construction of the 2nd Tomei-Meishin Expressway. The extradosed PC bridge is considered to have intermediate structural characteristics of those of the conventional beam bridge and PC cable stayed bridge, and is expected to be applied to bridges having approximately from 100 to 200m span. The features of the extradosed PC bridge is outlined. Approximately 1/35 beam height on the intermediate support and 1/10 main tower height against the center span are considered to be proper. PC steel products can be used efficiently because stress fluctuation of diagonals and the load sharing rate of the diagonal member are less than those of the PC cable stayed bridge and safety factor similar to that of general internal cable can be adopted. Construction works for the main tower and the diagonal member are easy due to low height of the main tower, and the bridge is advantageous also in the maintenance control because no beam is required. 5 refs., 8 figs., 2 tabs.

Iron phthalocyanine supported on amidoximated PAN fiber as effective catalyst for controllable hydrogen peroxide activation in oxidizing organic dyes

Energy Technology Data Exchange (ETDEWEB)

Han, Zhenbang, E-mail: hzbang@aliyun.com [School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Key Laboratory of Advanced Textile Composite Materials, Ministry of Education of China, Tianjin 300387 (China); Han, Xu [School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Zhao, Xiaoming, E-mail: zhaoxiaoming@tjpu.edu.cn [School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Key Laboratory of Advanced Textile Composite Materials, Ministry of Education of China, Tianjin 300387 (China); Yu, Jiantao; Xu, Hang [School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China)

2016-12-15

Iron(II) phthalocyanine was immobilized onto amidoximated polyacrylonitrile fiber to construct a bioinspired catalytic system for oxidizing organic dyes by H{sub 2}O{sub 2} activation. The amidoxime groups greatly helped to anchor Iron(II) phthalocyanine molecules onto the fiber through coordination interaction, which has been confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and UV diffuse reflectance spectroscopy analyses. Electron spin resonance studies indicate that the catalytic process of physically anchored Iron(II) phthalocyanine performed via a hydroxyl radical pathway, while the catalyst bonded Iron(II) phthalocyanine through coordination effect could selectively catalyze the H{sub 2}O{sub 2} decomposition to generate high-valent iron-oxo species. This may result from the amidoxime groups functioning as the axial fifth ligands to favor the heterolytic cleavage of the peroxide O−O bond. This feature also enables the catalyst to only degrade the dyes adjacent to the catalytic active centers and enhances the efficient utilization of H{sub 2}O{sub 2}. In addition, this catalyst could effectively catalyze the mineralization of organic dyes and can be easily recycled without any loss of activity.

Bis(2,3,5,6-tetra-2-pyridylpyrazine-κ3N2,N1,N6iron(II bis(dicyanamidate 4.5-hydrate

Directory of Open Access Journals (Sweden)

R. Cortés

2010-03-01

Full Text Available In the title compound, [Fe(C24H16N62][N(CN2]2·4.5H2O, the central iron(II ion is hexacoordinated by six N atoms of two tridentate 2,3,5,6-tetra-2-pyridylpyrazine (tppz ligands. Two dicyanamide anions [dca or N(CN2−] act as counter-ions, and 4.5 water molecules act as solvation agents. The structure contains isolated cationic iron(II–tppz complexes and the final neutrality is obtained with the two dicyanamide anions. One of the dicyanamide anions and a water molecule are disordered with an occupancy ratio of 0.614 (8:0.386 (8. O—H...O, O—H...N and C—H...O hydrogen bonds involving dca, water and tppz molecules are observed.

Bridges

NARCIS (Netherlands)

Zant, W.

2017-01-01

We estimate to what extent bridges in Mozambique lead to transport cost reductions and attribute these reductions to key determinants, in particular road distance, road quality and crossing borders. For identification we exploit the introduction of a road bridge over the Zambezi river, in August

NASA Operation IceBridge Flies Into the Classroom!

Science.gov (United States)

Kane, M.

2017-12-01

Field research opportunities for educators is leveraged as an invaluable tool to increase public engagement in climate research and the geosciences. We investigate the influence of educator's authentic fieldwork by highlighting the post-field impacts of a PolarTREC Teacher who participated in two campaigns, including NASA Operation IceBridge campaign over Antarctica in 2016. NASA's Operation IceBridge has hosted PolarTREC teachers since 2012, welcoming five teachers aboard multiple flights over the Arctic and one over Antarctica. The continuity of teacher inclusion in Operation IceBridge campaigns has facilitated a platform for collaborative curriculum development and revision, integration of National Snow and Ice Data Center (NSIDC) data into multiple classrooms, and given us a means whereby students can interact with science team members. I present impacts to my teaching and classrooms as I grapple with "Big Data" to allow students to work directly with lidar and radar data, I examine public outreach impacts through analytics from virtual networking tools including social media, NASA's Mission Tools Suite for Education, and field blog interactions.

Linking Science and Society With an Environmental Information Bridge

Science.gov (United States)

Welling, L.; Seielstad, G.; Jones, D.; Peterson, J.

2001-12-01

Building learning communities to engage the public in identifying and solving local and regional environmental problems is the vision of the newly created Northern Great Plains Center for People and the Environment at the University of North Dakota. The Center serves as an Environmental Information Bridge between science and society for citizens of the region, providing information, data, and value-added remote sensing products to precision agriculture, sustainable forestry, Native American land managers, and K-lifetime educators. Guided by the needs of end users, the new Center is a prototype for a national infrastructure that meets ESE's objective to "expand and accelerate the realization of economic and societal benefits from Earth science, information, and technology". The scientific community has been good at converting raw data into useful information. However, a serious communications gap exists between the communities of scientists and non-scientists. The new Center bridges this gap, creating a many-to-many exchange of information among those who learn first about the environment and those who will put those lessons to work for their economic welfare, the betterment of the quality of their lives, and the benefit of their descendants. A major outreach component of the Center, written and produced at UND, is Our Changing Planet, a public television series aimed at increasing viewers' awareness of environmental and climate change issues. Now carried by approximately 30 public television stations the series is distributed nationwide by the National Education Television Association. The Center has also recently established a partnership with StormCenter.com, LLC, a multimedia company and fellow partner in NASA's Federation of Earth Science Information Partners that uses leading-edge technology to deliver information about the environment to regional television stations. Service to the media provides a vital link between science and the public, as local weather

Field performance of timber bridges. 4, Graves Crossing stress-laminated deck bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter

The Graves Crossing bridge was constructed October 1991 in Antrim County, Michigan, as part of the demonstration timber bridge program sponsored by the USDA Forest Service. The bridge is a two-span continuous, stress-laminated deck superstructure and it is 36-ft long and 26-ft wide. The bridge is one of the first stress-laminated deck bridges to be built of sawn lumber...

Online Bridge Crack Monitoring with Smart Film

Directory of Open Access Journals (Sweden)

Benniu Zhang

2013-01-01

Full Text Available Smart film crack monitoring method, which can be used for detecting initiation, length, width, shape, location, and propagation of cracks on real bridges, is proposed. Firstly, the fabrication of the smart film is developed. Then the feasibility of the method is analyzed and verified by the mechanical sensing character of the smart film under the two conditions of normal strain and crack initiation. Meanwhile, the coupling interference between parallel enameled wires of the smart film is discussed, and then low-frequency detecting signal and the custom communication protocol are used to decrease interference. On this basis, crack monitoring system with smart film is designed, where the collected crack data is sent to the remote monitoring center and the cracks are simulated and recurred. Finally, the monitoring system is applied to six bridges, and the effects are discussed.

Myocardial Bridging

Directory of Open Access Journals (Sweden)

Shi-Min Yuan

2016-02-01

Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

The hepatic bridge.

Science.gov (United States)

Sugarbaker, Paul H

2018-07-01

The hepatic bridge forms a tunnel of liver parenchyma that may obscure peritoneal metastases associated with the round ligament. Visualization and then resection of nodules associated with this structure is necessary. The incidence of a hepatic bridge and the extent that it covered the round ligament was determined in consecutive patients. Extent of coverage of the round ligament by the hepatic bridge was determined: Class 1 indicates up to one-third of the round ligament obscured, Class 2 up to two-thirds and Class 3 more than two-thirds. In 102 patients in whom the round ligament of the liver could be completely visualized, 50 had a hepatic bridge. Class 1 was 22 (44%) of the bridges, Class 2 was 16 (32%) and Class 3 was 12 (24%). A hepatic bridge was more frequently present in 28 of 45 male patients (62%) vs. 22 of 57 female patients (38%). Approximately one-half of our patients having cytoreductive surgery for peritoneal metastases were observed to have a hepatic bridge. Up to 56% of these patients have Class 2 or 3 hepatic bridge and may require division of the hepatic bridge to completely visualize the contents of the tunnel created by this structure. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Characteristics of a plasma flow field produced by a metal array bridge foil explosion

Science.gov (United States)

Junying, WU; Long, WANG; Yase, LI; Lijun, YANG; Manzoor, SULTAN; Lang, CHEN

2018-07-01

To improve the energy utilization efficiency of metal bridge foil explosion, and increase the function range of plasmas, array bridge foil explosion experiments with different structures were performed. A Schlieren photographic measurement system with a double-pulse laser source was used to observe the flow field of a bridge foil explosion. The evolution laws of plasmas and shock waves generated by array bridge foil explosions of different structures were analyzed and compared. A multi-phase flow calculation model was established to simulate the electrical exploding process of a metal bridge foil. The plasma equation of state was determined by considering the effect of the changing number of particles and Coulomb interaction on the pressure and internal energy. The ionization degree of the plasma was calculated via the Saha–Eggert equation assuming conditions of local thermal equilibrium. The exploding process of array bridge foils was simulated, and the superposition processes of plasma beams were analyzed. The variation and distribution laws of the density, temperature, pressure, and other important parameters were obtained. The results show that the array bridge foil has a larger plasma jet diameter than the single bridge foil for an equal total area of the bridge foil. We also found that the temperature, pressure, and density of the plasma jet’s center region sharply increase because of the superposition of plasma beams.

Bridged graphite oxide materials

Science.gov (United States)

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

2010-01-01

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

Laboratory and field testing of an accelerated bridge construction demonstration bridge : US Highway 6 bridge over Keg Creek.

Science.gov (United States)

2013-04-01

The US Highway 6 Bridge over Keg Creek outside of Council Bluffs, Iowa is a demonstration bridge site chosen to put into practice : newly-developed Accelerated Bridge Construction (ABC) concepts. One of these new concepts is the use of prefabricated ...

Smart timber bridge on geosynthetic reinforced soil (GRS) abutments

Science.gov (United States)

Adam Senalik; James P. Wacker; Travis K. Hosteng; John Hermanson

2017-01-01

Recently, Buchanan County, Iowa, has cooperated with the U.S. Federal Highway Administration (FHWA), USDA Forest Service, Forest Products Laboratory (FPL), and Iowa State University’s Bridge Engineering Center (ISU–BEC) to initiate a project involving the construction and monitoring of a glued-laminated (glulam) timber superstructure on geosynthetic reinforced soil (...

Guardrails for Use on Historic Bridges: Volume 2—Bridge Deck Overhang Design

OpenAIRE

Frosch, Robert J.; Morel, Adam J.

2016-01-01

Bridges that are designated historic present a special challenge to bridge engineers whenever rehabilitation work or improvements are made to the bridges. Federal and state laws protect historically significant bridges, and railings on these bridges can be subject to protection because of the role they play in aesthetics. Unfortunately, original railings on historic bridges do not typically meet current crash-test requirements and typically do not meet current standards for railing height and...

Dynamic assessment of bridge deck performance considering realistic bridge-traffic interaction

Science.gov (United States)

2017-09-01

Concrete bridge decks are directly exposed to daily traffic loads and may experience some surface cracking caused by excessive stress or fatigue accumulation, which requires repair or replacement. Among typical bridges in North America, bridge decks ...

Identification of localized redox states in plant-type two-iron ferrodoxins using the nuclear Overhauser effect

International Nuclear Information System (INIS)

Dugad, L.B.; La Mar, G.N.; Banci, L.; Bertini, I.

1990-01-01

The homonuclear Overhauser effect (NOE), in conjunction with nonselective spin-lattice relaxation measurements, has been employed to assign the contact-shifted resonances for the reduced form of two typical plant-type two-iron ferrodoxins from the algae Spirulina platensis and Porphyra umbilicalis. These results demonstrate that the NOE should have broad general applicability for the assignments and electronic structural elucidation of diverse subclasses of paramagnetic iron-sulfur cluster proteins. NOE connectivities were detected only among sets of resonances exhibiting characteristically different deviations from Curie behavior, providing strong support for the applicability of the spin Hamiltonian formulation for the NMR properties of the antiferromagnetically coupled iron clusters. The geminal β-methylene protons for the two cysteines bound to the iron(II) center were clearly identified, as well as the C α H and one C β H for each of the cysteines bound to the iron(III). The identification of the iron bound to cysteines 41 and 46 as the iron(II) in the reduced protein was effected on the basis of dipolar contacts between the bound cysteines. Resolved labile proton contact-shifted resonances are attributed to hydrogen bonding to the iron(III) center, and it is concluded that the contact-shifted resonances for the more numerous hydrogen bonds to the iron(II) center are not resolved from the diamagnetic envelope. The identification of the iron closer to the protein surface as the more reducible one is consistent with predictions based on a larger number of hydrogen bonds to this center

Cable Supported Bridges

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

Ligand-bridged dinuclear cyclometalated Ir(III) complexes: from metallamacrocycles to discrete dimers.

Science.gov (United States)

Chandrasekhar, Vadapalli; Hajra, Tanima; Bera, Jitendra K; Rahaman, S M Wahidur; Satumtira, Nisa; Elbjeirami, Oussama; Omary, Mohammad A

2012-02-06

Metallamacrocycles 1, 2, and 3 of the general formula [{Ir(ppy)(2)}(2)(μ-BL)(2)](OTf)(2) (ppyH = 2-phenyl pyridine; BL = 1,2-bis(4-pyridyl)ethane (bpa) (1), 1,3-bis(4-pyridyl)propane (bpp) (2), and trans-1,2-bis(4-pyridyl)ethylene (bpe) (3)) have been synthesized by the reaction of [{(ppy)(2)Ir}(2)(μ-Cl)(2)], first with AgOTf to effect dechlorination and later with various bridging ligands. Open-frame dimers [{Ir(ppy)(2)}(2)(μ-BL)](OTf)(2) were obtained in a similar manner by utilizing N,N'-bis(2-pyridyl)methylene-hydrazine (abp) and N,N'-(bis(2-pyridyl)formylidene)ethane-1,2-diamine (bpfd) (for compounds 4 and 5, respectively) as bridging ligands. Molecular structures of 1, 3, 4, and 5 were established by X-ray crystallography. Cyclic voltammetry experiments reveal weakly interacting "Ir(ppy)(2)" units bridged by ethylene-linked bpe ligand in 3; on the contrary the metal centers are electronically isolated in 1 and 2 where the bridging ligands are based on ethane and propane linkers. The dimer 4 exhibits two accessible reversible reduction couples separated by 570 mV indicating the stability of the one-electron reduced species located on the diimine-based bridge abp. The "Ir(ppy)(2)" units in compound 5 are noninteracting as the electronic conduit is truncated by the ethane spacer in the bpfd bridge. The dinuclear compounds 1-5 show ligand centered (LC) transitions involving ppy ligands and mixed metal to ligand/ligand to ligand charge transfer (MLCT/LLCT) transitions involving both the cyclometalating ppy and bridging ligands (BL) in the UV-vis spectra. For the conjugated bridge bpe in compound 3 and abp in compound 4, the lowest-energy charge-transfer absorptions are red-shifted with enhanced intensity. In accordance with their similar electronic structures, compounds 1 and 2 exhibit identical emissions. The presence of vibronic structures in these compounds indicates a predominantly (3)LC excited states. On the contrary, broad and unstructured

IceBridge NSERC L1B Geolocated Meteorologic and Surface Temperature Data, Version 1

Data.gov (United States)

National Aeronautics and Space Administration — The IceBridge National Suborbital Education & Research Center (NSERC) L1B Geolocated Meteorologic and Surface Temperature (IAMET1B) data set is a collection of...

Bridge Programs in Illinois: Results of the 2010 Illinois Bridge Status Survey

Science.gov (United States)

Taylor, J. L.; Harmon, T.

2010-01-01

This report provides a summary of major results of the Illinois Bridge Status Survey, administered online between April and June 2010. The purpose of the survey was to understand the extent to which bridge programs are being implemented in Illinois, as well as to build an online directory of bridge programs. Bridge programs are an emerging…

Field performance of timber bridges. 6, Hoffman Run stress-laminated deck bridge

Science.gov (United States)

M. A. Ritter; P. D. Hilbrich Lee; G. J. Porter

The Hoffman Run bridge, located just outside Dahoga, Pennsylvania, was constructed in October 1990. The bridge is a simple-span, single-lane, stress-laminated deck superstructure that is approximately 26 ft long and 16 ft wide. It is the second stress-laminated timber bridge to be constructed of hardwood lumber in Pennsylvania. The performance of the bridge was...

Drill pipe bridge plug

International Nuclear Information System (INIS)

Winslow, D.W.; Brisco, D.P.

1991-01-01

This patent describes a method of stopping flow of fluid up through a pipe bore of a pipe string in a well. It comprises: lowering a bridge plug apparatus on a work string into the pipe string to a position where the pipe bore is to be closed; communicating the pipe bore below a packer of the bridge plug apparatus through the bridge plug apparatus with a low pressure zone above the packer to permit the fluid to flow up through the bridge plug apparatus; engaging the bridge plug apparatus with an internal upset of the pipe string; while the fluid is flowing up through the bridge plug apparatus, pulling upward on the work string and the bridge plug apparatus and thereby sealing the packer against the pipe bore; isolating the pipe bore below the packer from the low pressure zone above the packer and thereby stopping flow of the fluid up through the pipe bore; disconnecting the work string from the bridge plug apparatus; and maintaining the bridge plug apparatus in engagement with the internal upset and sealed against the pipe bore due to an upward pressure differential applied to the bridge plug apparatus by the fluid contained therebelow

Bridging the Gap

DEFF Research Database (Denmark)

Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska

Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

Two Alternative Approaches to Creating Opportunities for Entrepreneurial Activity: Bridging the Divide between Academics and Entrepreneurs.

Science.gov (United States)

Weaver, K. Mark

1993-01-01

This article shows how the Norwegian Small Business Research Center and the Alabama International Trade Center have set goals and established procedures to bridge gaps and correct misconceptions between academics and entrepreneurs. Keys to formation of both organizations were involvement of well-thought of universities, a willingness to take a…

Long Span Bridges in Scandinavia

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1998-01-01

The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europe...... is found in Scandinavia - the 1210 m span of the Höga Kusten Bridge in Sweden.The Kvarnsund Bridge in Norway was at the completion in 1991 the longest cable-stayed bridge in the world, and the span of 530 m is still thge longest for cable-stayed bridges in concrete. The Øresund Bridge with its sapn of 490...

Kisspeptins: bridging energy homeostasis and reproduction

DEFF Research Database (Denmark)

Castellano, Juan M; Bentsen, Agnete H; Mikkelsen, Jens D

2010-01-01

and reproduction have been the subject of considerable attention; however, our understanding of the neurobiological basis for this phenomenon is still incomplete. In mid 1990s, the adipose-hormone, leptin, was proven as an essential signal for transmitting metabolic information onto the centers governing puberty......RH neurons. This review recapitulates the experimental evidence obtained to date, mostly in laboratory rodents, supporting the function of kisspeptins in bridging energy balance and reproduction, with special emphasis on recent developments in this field, such as the recognition of mTOR (mammalian target...

Integral Abutment and Jointless Bridges

Directory of Open Access Journals (Sweden)

Cristian-Claudiu Comisu

2005-01-01

Full Text Available Integral bridges, or integral abutment and jointless bridges, as they are more commonly known in the USA, are constructed without any movement joints between spans or between spans and abutments. Typically these bridges have stub-type abutments supported on piles and continuous bridge deck from one embankment to the other. Foundations are usually designed to be small and flexible to facilitate horizontal movement or rocking of the support. Integrally bridges are simple or multiple span ones that have their superstructure cast integrally with their substructure. The jointless bridges cost less to construct and require less maintenance then equivalent bridges with expansion joints. Integral bridges present a challenge for load distribution calculations because the bridge deck, piers, abutments, embankments and soil must all be considered as single compliant system. This paper presents some of the important features of integral abutment and jointless bridge design and some guidelines to achieve improved design. The goal of this paper is to enhance the awareness among the engineering community to use integral abutment and jointless bridges in Romania.

Bridge deterioration models to support Indiana's bridge management system.

Science.gov (United States)

2016-02-01

An effective bridge management system that is equipped with reliable deterioration models enables agency engineers to carry out : monitoring and long-term programming of bridge repair actions. At the project level, deterioration models help the agenc...

Automatic Bridge Control System

OpenAIRE

M. Niraimathi; S.Sivakumar; R.Vigneshwaran; R.Vinothkumar; P.Babu

2012-01-01

Bridge vibration control is an important issue whose purpose is to extend the structural service life of bridges. Normally, the bridge is modeled as an elastic beam or plate subject to a moving vehicle. However, the moving truck on a bridge is a complicated problem that must still be researched. In this paper, wepropose a new method, to overcome the huge load in the bridge a load cell is used at the entry which will monitor the load continuously at both ends. To escape from the heavy water fl...

Spin density measurement of water-bridged Co-dimer using polarized neutrons

DEFF Research Database (Denmark)

Damgaard-Møller, Emil; Overgaard, Jacob; Chilton, Nick

present an experimentally determined spin density using polarized neutron diffraction in a simple water-bridged cobalt dimer [Co2(H2O)(piv)4(Hpiv)2(py)2] which is known to have a small ferromagnetic coupling between the spin centers. Visualizing the SDD could get us one step further in understanding...

Construction of the Usui bridge. Chodai PC shachokyo no kensetsu (Joshin'etsu jidoshado Usuikyo)

Energy Technology Data Exchange (ETDEWEB)

Otani, S.; Ogata, T. (Japan Highway Public Corp., Tokyo (Japan))

1993-10-01

The Usui Bridge is a long bridge located at the Usui mountain pass on the Joshinetsu Expressway, completed in March 1993. This paper reports from its planning to the design, construction work, and construction management. The bridge is a first two-span continuous prestressed concrete cable-stayed bridge (with a length of 222 m) with one central cable plane ever constructed as a highway bridge in Japan. Its bridge construction features are represented by the main girder consisted of three-chamber type box girder, and the main tower of reversed Y-letter concrete structure. For the fan-shaped stay cable (9-step double cable), a large capacity cable of non-grouting type fabricated at a factory (with a tensile strength of 1500 tf class) was used to simplify the installation work at the site. The one-plane structure utilizing the center belt as a stay cable fixing portion was adopted because of its economic performance superior to a two-plane structure, easiness in consolidating construction works, and assurance of more open space for car traffic. After the completion, the bridge construction has been awarded with the Tanaka Prize of Japan Society of Civil Engineers and the PC Technology Association prize. 26 figs., 4 tabs.

Existing Steel Railway Bridges Evaluation

Science.gov (United States)

Vičan, Josef; Gocál, Jozef; Odrobiňák, Jaroslav; Koteš, Peter

2016-12-01

The article describes general principles and basis of evaluation of existing railway bridges based on the concept of load-carrying capacity determination. Compared to the design of a new bridge, the modified reliability level for existing bridges evaluation should be considered due to implementation of the additional data related to bridge condition and behaviour obtained from regular inspections. Based on those data respecting the bridge remaining lifetime, a modification of partial safety factors for actions and materials could be respected in the bridge evaluation process. A great attention is also paid to the specific problems of determination of load-caring capacity of steel railway bridges in service. Recommendation for global analysis and methodology for existing steel bridge superstructure load-carrying capacity determination are described too.

Field performance of timber bridges. 5, Little Salmon Creek stress-laminated deck bridge

Science.gov (United States)

M. A. Ritter; J. A. Kainz; G. J. Porter

The Little Salmon Creek bridge was constructed in November 1988 on the Allegheny National Forest in Pennsylvania. The bridge is a simple span, single-lane, stress-laminated deck superstructure that is approximately 26-ft long and 16-ft wide. The bridge is unique in that it is the first known stress-laminated timber bridge to be constructed of hardwood lumber. The...

D0 Silicon Upgrade: End Calorimeter Transfer Bridge Design and Installation Procedures

International Nuclear Information System (INIS)

Stredde, H.J.

1991-01-01

The North Endcap Calorimeter (NEC) is to be moved from the clean room to the north sidewalk in preparation for the final installation on the DO detector center beam. In order to make this move, the cable bridge must be 'flattened' and the NEC lifted to move over it. The detector is moved west, approximately 24 feet, while the moveable counting house remains stationary. This movement allows the cable bridge to 'flatten' i.e. become horizontal. The cable bridge lowering is steadied and stabilized by 7.5 ton hoist mounted on the moveable counting house. By moving the detector to lower the bridge, a vacancy has been created in the pit that must be filled to the level of the clean room rail elevation. This filler will consist of concrete shield blocks, stacked in two rows. These rows are spaced appropriately to match the wheel base of the EC transporter. A steel plate is placed on top of each row of shield blocks and leveled to the elevation of the clean room rails. Steel plates will be installed and leveled on the north sidewalk similar to those used on the south sidewalk for the CC installation. These plates are used as rails for the Hilman rollers, bearing surfaces for shim blocks used during lifting and anchors for holding the transporter extension units and the transfer bridge. After the plates are installed, the transfer bridge is put in place, spanning the cable bridge, shimmed and leveled. The transporter extension units are positioned next to the transfer bridge on the north sidewalk. With the completion of this prep work, the actual transfer of the NEC from the clean room can begin. The NEC is pulled from the clean room with the same mechanism (cyl. and chain) that was used for the CC and the pull anchor point will be located at the end of the concrete blocks. The NEC will come out of the north west door in the clean room and move along the temporary rail plates in the pit until it is in line with the transfer bridge. At this point the NEC is ready to be

Structure-borne low-frequency noise from multi-span bridges: A prediction method and spatial distribution

Science.gov (United States)

Song, X. D.; Wu, D. J.; Li, Q.; Botteldooren, D.

2016-04-01

Structure-borne noise from railway bridges at far-field points is an important indicator in environmental noise assessment. However, studies that predict structure-borne noise tend to model only single-span bridges, thus ignoring the sound pressure radiating from adjacent spans. To simulate the noise radiating from multi-span bridges induced by moving vehicles, the vibrations of a multi-span bridge are first obtained from a three-dimensional (3D) vehicle-track-bridge dynamic interaction simulation using the mode superposition method. A procedure based on the 2.5-dimensional (2.5D) boundary element method (BEM) is then presented to promote the efficiency of acoustical computation compared with the 3D BEM. The simulated results obtained from both the single-span and multi-span bridge models are compared with the measured results. The sound predictions calculated from the single-span model are accurate only for a minority of near-field points. In contrast, the sound pressures calculated from the multi-span bridge model match the measured results in both the time and frequency domains for all of the near-field and far-field points. The number of bridge spans required in the noise simulation is then recommended related to the distance between the track center and the field points of interest. The spatial distribution of multi-span structure-borne noise is also studied. The variation in sound pressure levels is insignificant along the length of the bridge, which validates the finding that the sound test section can be selected at an arbitrary plane perpendicular to the multi-span bridge.

Hydraulic modeling of flow impact on bridge structures: a case study on Citarum bridge

Science.gov (United States)

Siregar, R. I.

2018-02-01

Flood waves because of the rapid catchment response to high intense rainfall, breaches of flood defenses may induce huge impact forces on structures, causing structural damage or even failures. Overflowing stream that passes over the bridge, it means to discharge flood water level is smaller than the capacity of the river flow. In this study, the researches present the methodological approach of flood modeling on bridge structures. The amount of force that obtained because of the hydrostatic pressure received by the bridge at the time of the flood caused the bridge structure disrupted. This paper presents simulation of flow impact on bridge structures with some event flood conditions. Estimating the hydrostatic pressure developed new model components, to quantify the flow impact on structures. Flow parameters applied the model for analyzing, such as discharge, velocity, and water level or head that effect of bridge structures. The simulation will illustrate the capability of bridge structures with some event flood river and observe the behavior of the flow that occurred during the flood. Hydraulic flood modeling use HEC-RAS for simulation. This modeling will describe the impact on bridge structures. Based on the above modelling resulted, in 2008 has flood effect more than other years on the Citarum Bridge, because its flow overflow on the bridge.

Existing Steel Railway Bridges Evaluation

Directory of Open Access Journals (Sweden)

Vičan Josef

2016-12-01

Full Text Available The article describes general principles and basis of evaluation of existing railway bridges based on the concept of load-carrying capacity determination. Compared to the design of a new bridge, the modified reliability level for existing bridges evaluation should be considered due to implementation of the additional data related to bridge condition and behaviour obtained from regular inspections. Based on those data respecting the bridge remaining lifetime, a modification of partial safety factors for actions and materials could be respected in the bridge evaluation process. A great attention is also paid to the specific problems of determination of load-caring capacity of steel railway bridges in service. Recommendation for global analysis and methodology for existing steel bridge superstructure load-carrying capacity determination are described too.

Light-weight aluminium bridges and bridge decks. An overview of recent applications

NARCIS (Netherlands)

Maljaars, J.; Soetens, F.; Kluyver, D. de

2008-01-01

The last decades have shown a large increase in the application of aluminium alloys for light-weight bridges. For bridge construction, aluminium alloys have some specific advantages, but also some points of attention. This paper deals with some recent projects of aluminium bridges, and for these

Surprising Intrinsic Photostability of the Disulfide Bridge Common in Proteins

DEFF Research Database (Denmark)

Stephansen, Anne Boutrup; Brogaard, Rasmus Yding; Kuhlman, Thomas Scheby

2012-01-01

on the femtosecond time scale and found the reason for the existence of the S–S bridge as a natural building block in folded structures. The sulfur atoms will indeed move apart on the excited state but only to oscillate around the S–S center of mass. At long S–S distances, there is a strong coupling to the ground...

Gas supply triggers development at Connaught Bridge

Energy Technology Data Exchange (ETDEWEB)

Jeffs, E.

Malaysia aims to become a fully developed country by the year 2020, which means a steady 20% annual rate of growth of electricity demand to the end of the century. Much of this growth is centered in the area around Kuala Lumpur so that Tenaga Nasional Bhd (Tenaga) urgently needs to bring new generating capacity into the capital area. Access to gas on the west coast of the malay peninsula has given Tenaga Nasional Berhad the opportunity to convert their Connaught Bridge power station to a combined cycle and to install four open-cycle gas turbines. The expansion of Connaught Bridge is the first of several projects which are being developed. In early 1991, as site preparation was getting under way for the combined cycle, Tenaga ordered eight gas turbines for peak load duty from NEI-ABB Gas Turbines. Four of these are the 150 MW Type GT13E with water injection for NOx control which have been installed in parallel with the construction of the steam cycle on the Connaught Bridge site. At sea level and 32[degrees]C site ambient, these gas turbines are rated 130MW on gas for a total 520MW of peak load capacity. The last of these was synchronized on 12 October last year. There are no plans to convert these to combined cycles.

Development of bridge girder movement criteria for accelerated bridge construction.

Science.gov (United States)

2014-06-01

End diaphragms connect multiple girders to form a bridge superstructure system for effective resistance to earthquake loads. Concrete : girder bridges that include end diaphragms consistently proved to perform well during previous earthquake events. ...

Active Control of Suspension Bridges

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

Effect of the Debye screening on the tunnel current through simple electrochemical bridged contact

DEFF Research Database (Denmark)

Kuznetsov, A.M.; Medvedev, Oleg; Ulstrup, Jens

2008-01-01

General equations for tunnel current through electrochemical contact containing a redox-center in molecular bridge group are observed with allowing for potential distribution in the tunnel gap. Simple approximate expressions appropriate for the analysis of experimental data are also derived. The ...

Bridging the divide: building infrastructure to support community-academic partnerships and improve capacity to conduct patient-centered outcomes research.

Science.gov (United States)

Huang, Jennifer; Lipman, Paula Darby; Daniel Mullins, C

2017-12-01

For research to be useful, trustworthy, and ultimately lead to greater dissemination of findings to patients and communities, it is important to train and mentor academic researchers to meaningfully engage community members in patient-centered outcomes research (PCOR). Thus, it is necessary for research institutions to strengthen their underlying infrastructure to support PCOR. PATIENTS-PATient-centered Involvement in Evaluating effectiveNess of TreatmentS-at the University of Maryland, Baltimore, focuses on improving PCOR methods and addressing health disparities. It relies on evidence-based engagement methods to sustain and leverage innovative partnerships so patients, health care providers, and academic partners are motivated to participate in the conduct and dissemination of PCOR. Program components address training needs, bi-directional engagement, cultural competency, and dissemination and implementation. Activities (guided by community representatives, leadership from university schools, patient advocates, and PCOR experts) include providing resources, conducting PCOR projects, engaging community members, and disseminating PCOR findings. With its emphasis on the broad range of PCOR topics and methods, and through fostering sustainable relationships with community members and researchers, PATIENTS has successfully cultivated bi-directional partnerships and provided operational and scientific support for a new generation of skilled PCOR researchers. Early evidence of effectiveness includes progress in training and mentoring students and investigators, an increase in submission of PCOR proposals, and community-informed strategies for dissemination. Programs such as PATIENTS reinforce the value of bridging the traditional divide between academia and communities to support patient- and community-engaged dissemination and implementation research and foster sustainable PCOR infrastructure.

Morphological aspects of myocardial bridges.

Science.gov (United States)

Lujinović, Almira; Kulenović, Amela; Kapur, Eldan; Gojak, Refet

2013-11-01

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

Field performance of timber bridges. 17, Ciphers stress-laminated deck bridge

Science.gov (United States)

James P. Wacker; James A. Kainz; Michael A. Ritter

In September 1989, the Ciphers bridge was constructed within the Beltrami Island State Forest in Roseau County, Minnesota. The bridge superstructure is a two-span continuous stress-laminated deck that is approximately 12.19 m long, 5.49 m wide, and 305 mm deep (40 ft long, 18 ft wide, and 12 in. deep). The bridge is one of the first to utilize red pine sawn lumber for...

Remarks on crack-bridging concepts

International Nuclear Information System (INIS)

Bao, G.; Suo, Z.

1992-01-01

The article draws upon recent work by us and our colleagues on metal and ceramic matrix composites for high temperature engines. The central theme here is to deduce mechanical properties, such as toughness, strength and notch-ductility, from bridging laws that characterize inelastic processes associated with fracture. A particular set of normalization is introduced to present the design charts, segregating the roles played by the shape, and the scale, of a bridging law. A single material length, γ 0 E/σ 0 , emerges, where γ 0 is the limiting-separation, σ 0 the bridging-strength, and E the Young's modulus of the solid. It is the huge variation of this length-from a few manometers for atomic bond, to a meter for cross-over fibers - that underlies the richness in material behaviors. Under small-scale bridging conditions, γ 0 E/σ 0 is the only basic length scale in the mechanics problem and represents, with a pre-factor about 0.4, the bridging zone size. A catalog of small-scale bridging solutions is compiled for idealized bridging laws. Large-scale bridging introduces a dimensionless group, a/(γ 0 E/σ 0 ), where a is a length characterizing the component. The group plays a major role in all phenomena associated with bridging, and provides a focus of discussion in this article. For example, it quantifies the bridging scale when a is the unbridged crack length, and notch-sensitivity when a is hole radius. The difference and the connection between Irwin's fracture mechanics and crack bridging concepts are discussed. It is demonstrated that fracture toughness and resistance curve are meaningful only when small-scale bridging conditions prevail, and therefore of limited use in design with composites. Many other mechanical properties of composites, such as strength and notch-sensitivity, can be simulated by invoking large-scale bridging concepts. 37 refs., 21 figs., 3 tabs

Design and construction of the Daini-Chikumagawa bridge; Dai ni Chikumagawa kyoryo no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Inaba, N.; Takasusuki, K.; Hirasawa, T.; Kanamori, M.

1996-01-30

The Daini-Chikumagawa bridge, having spans of 134m {times} 2 which is the largest in Japan as the concrete railroad, is a prestressed concrete (PC) oblique cable-stayed bridge building on the Hokuriku Shinkansen express line which is constructing towards Nagano Olympic (Feb.1998). Regarding adoption of the oblique cable-stayed bridge for the railroad bridge, there are very few examples on a global scale and in Japan besides this bridge there is only one example (Omoto bridge (Iwate pref.), span = 85m). One H type tower (H = 65m from the surface of bridge) is erected at the center of the Chikuma river and then main girders are built at the front and rear of this tower. These main girders, being separated into 5m {times} 24 blocks per one side excepting surroundings of the tower, are fabricated as a three room box type PC block (total width 12.8m; height 3.0m) each on the river beach near the spot. These blocks are jointed from the tower side by the overhanging work using the constructing vehicles and are fixed with oblique materials (cables; two face hanging system) at intervals of 10m. 4 refs., 16 figs., 5 tabs.

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

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Movable bridge, interlocking of signal appliances with bridge devices. 236.312 Section 236.312 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Interlocking Standards § 236.312 Movable bridge, interlocking of signal...

Cooperativity of complex salt bridges

OpenAIRE

Gvritishvili, Anzor G.; Gribenko, Alexey V.; Makhatadze, George I.

2008-01-01

The energetic contribution of complex salt bridges, in which one charged residue (anchor residue) forms salt bridges with two or more residues simultaneously, has been suggested to have importance for protein stability. Detailed analysis of the net energetics of complex salt bridge formation using double- and triple-mutant cycle analysis revealed conflicting results. In two cases, it was shown that complex salt bridge formation is cooperative, i.e., the net strength of the complex salt bridge...

Comprehensive evaluation of fracture critical bridges.

Science.gov (United States)

2014-02-01

Two-girder steel bridges are classified as fracture critical bridges based on the definition given in the AASHTO LRFD Bridge Design Specifications. In a fracture critical bridge a failure of a tension member leads to collapse of the bridge. However, ...

Timber in Bridge Structures

OpenAIRE

Detkin, Viktoria

2016-01-01

The purpose of this final year project was to study the properties of timber as a structural material and the suitability of wood in load bearing members for bridge structures. For a case study, an existing timber bridge was selected. Due to its condition the bridge should be replaced. The design of a new bridge with steel beams holding a glulam deck was made. During the case study the replacement of steel beams by glulam timber ones was discussed. Some calculations were made in order to ...

Field performance of timber bridges. 16, North Siwell Road stress-laminated bridge

Science.gov (United States)

J. A. Kainz

The North Siwell Road bridge was constructed during December 1994 in Hinds County, Mississippi. The bridge is a single-span, stress-laminated T-beam structure that measures 9.1 m (30 ft) long and 8.7 m (28.5 ft) wide. Performance of the bridge was monitored for 24 months, beginning at the time of installation. Monitoring involved gathering and evaluating data relative...

Field performance of timber bridges. 10, Sanborn Brook stress-laminated deck bridge

Science.gov (United States)

P. D. Hilbrich Lee; J. P. Wacker; M. A. Ritter

The Sanborn Brook bridge was constructed in August 1991, 10 miles northeast of Concord, New Hampshire, as part of the demonstration timber bridge program of the USDA Forest Service. The bridge is a simple-span, double-lane, stress-laminated deck superstructure constructed from Southern Pine lumber and is approximately 25 ft long and 28 ft wide with a skew of 14 degrees...

Simulation of multivariate diffusion bridges

DEFF Research Database (Denmark)

Bladt, Mogens; Finch, Samuel; Sørensen, Michael

We propose simple methods for multivariate diffusion bridge simulation, which plays a fundamental role in simulation-based likelihood and Bayesian inference for stochastic differential equations. By a novel application of classical coupling methods, the new approach generalizes a previously...... proposed simulation method for one-dimensional bridges to the mulit-variate setting. First a method of simulating approzimate, but often very accurate, diffusion bridges is proposed. These approximate bridges are used as proposal for easily implementable MCMC algorithms that produce exact diffusion bridges...

Multisensor system for determination of iron(II), iron(III) and uranium(VI) in complex solutions

International Nuclear Information System (INIS)

Legin, A.V.; Seleznev, B.L.; Rudnitskaya, A.M.; Vlasov, Yu.G.

1998-01-01

The aim of the present paper is the development and analytical evaluation of a multisensor system for determination of low content of iron(II), iron(III) and uranium(VI) in complex aqueous media. Sensor array included sensors on the basis of chalcogenide vitreous materials with redox and ionic cross-sensitivities, crystalline silver sulphide electrode, noble metal electrodes Pt, Au, Ag and redox sensor on the basis of oxide glass. Potentiometric measurements have been taken in a conventional electrochemical cell vs. a standard Ag/AgCl reference electrode. All measurements have been taken at room temperature. Calibration solutions contained UO 2 (NO 3 ) 2 in concentration range 10 -6 -1,610 -5 mol/L, K 3 Fe(CN) 6 and K 4 Fe(CN) 6 or FeSO 4 (NH 4 ) 2 SO 4 and FeCl 3 , with the ratio of Fe(II)/Fe(III) concentration from 100:1 to 1:100, the total concentration of Fe was 10 -4 and 10 -5 mol/L. All solutions have been made on the background electrolyte of calcium and magnesium chlorides and sulphates with the fixed content of 5-27 mmol/L of each component which is a typical one for groundwater or mining water. Sensor potentials have been processed by a back-propagation artificial neural net. Average error of determination of Fe(II) and Fe(III) is about 20 %, of uranium(VI) - 40 %. It was found that sensitivity of the sensor array to iron and uranium is irrespective of the chemical form of these species

Steel-soil composite bridge

DEFF Research Database (Denmark)

Du, Guangli; Pettersson, Lars; Karoumi, Raid

2017-01-01

viability, while their environmental performance is overlooked. Today’s designers are urged to seek new design options to reduce the environmental burdens. Sweden owns more than 24574 bridges and most of them are short spans. Among them, the slab frame bridge (CFB) is a common solution. Soil steel composite...... bridge (SSCB), alternatively, is a functionally equivalent solution to CFB and shows advantages in low cost and easy construction. This paper compares the environmental performance between these two bridge types based on life cycle assessment (LCA). The analysis and result shows that, the SSCB...

Building water bridges in air: Electrohydrodynamics of the floating water bridge

Science.gov (United States)

Marín, Álvaro G.; Lohse, Detlef

2010-12-01

The interaction of electrical fields and liquids can lead to a phenomenon that defies intuition. Some famous examples can be found in electrohydrodynamics as Taylor cones, whipping jets, or noncoalescing drops. A less famous example is the floating water bridge: a slender thread of water held between two glass beakers in which a high voltage difference is applied. Surprisingly, the water bridge defies gravity even when the beakers are separated at distances up to 2 cm. In this paper, experimental measurements and simple models are proposed and discussed for the stability of the bridge and the source of the flow, revealing an important role of polarization forces on the stability of the water bridge. On the other hand, the observed flow can only be explained due to the non-negligible free charge present in the surface. In this sense, the floating water bridge can be considered as an extreme case of a leaky dielectric liquid [J. R. Melcher and G. I. Taylor, Annu. Rev. Fluid Mech. 1, 111 (1969)].

National Bridge Inventory (NBI) Bridges

Data.gov (United States)

Department of Homeland Security — The NBI is a collection of information (database) describing the more than 600,000 of the Nation's bridges located on public roads, including Interstate Highways,...

Bridging the Evaluation Gap

Directory of Open Access Journals (Sweden)

Paul Wouters

2017-02-01

Full Text Available Paul Wouters’ essay is concerned with bridging the gap between what we value in our academic work and how we are assessed in formal evaluation exercises. He reflects on the recent evaluation of his own center, and reminds us that it is productive to see evaluations not as the (obviously impossible attempt to produce a true representation of past work, but rather as the exploration and performance of “who one wants to be.” Reflecting on why STS should do more than just play along to survive in the indicator game, he suggests that our field should contribute to changing its very rules. In this endeavor, the attitude and sensibilities developed in our field may be more important than any specific theoretical concepts or methodologies.

Wright-Fisher diffusion bridges.

Science.gov (United States)

Griffiths, Robert C; Jenkins, Paul A; Spanò, Dario

2017-10-06

The trajectory of the frequency of an allele which begins at x at time 0 and is known to have frequency z at time T can be modelled by the bridge process of the Wright-Fisher diffusion. Bridges when x=z=0 are particularly interesting because they model the trajectory of the frequency of an allele which appears at a time, then is lost by random drift or mutation after a time T. The coalescent genealogy back in time of a population in a neutral Wright-Fisher diffusion process is well understood. In this paper we obtain a new interpretation of the coalescent genealogy of the population in a bridge from a time t∈(0,T). In a bridge with allele frequencies of 0 at times 0 and T the coalescence structure is that the population coalesces in two directions from t to 0 and t to T such that there is just one lineage of the allele under consideration at times 0 and T. The genealogy in Wright-Fisher diffusion bridges with selection is more complex than in the neutral model, but still with the property of the population branching and coalescing in two directions from time t∈(0,T). The density of the frequency of an allele at time t is expressed in a way that shows coalescence in the two directions. A new algorithm for exact simulation of a neutral Wright-Fisher bridge is derived. This follows from knowing the density of the frequency in a bridge and exact simulation from the Wright-Fisher diffusion. The genealogy of the neutral Wright-Fisher bridge is also modelled by branching Pólya urns, extending a representation in a Wright-Fisher diffusion. This is a new very interesting representation that relates Wright-Fisher bridges to classical urn models in a Bayesian setting. Copyright © 2017 Elsevier Inc. All rights reserved.

National Bridge Inventory System (NBI)

Data.gov (United States)

Department of Transportation — The NBI System is the collection of bridge inspection information and costs associated with bridge replacements of structurally deficient bridges on and off the NHS....

Bridge maintenance to enhance corrosion resistance and performance of steel girder bridges

Science.gov (United States)

Moran Yanez, Luis M.

The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. The benefit of regular high-pressure superstructure washing and spot painting were evaluated as effective maintenance activities to reduce the corrosion process. The effectiveness of steel girder washing was assessed by developing models of corrosion deterioration of composite steel girders and analyzing steel coupons at the laboratory under atmospheric corrosion for two alternatives: when high-pressure washing was performed and when washing was not considered. The effectiveness of spot painting was assessed by analyzing the corrosion on steel coupons, with small damages, unprotected and protected by spot painting. A parametric analysis of corroded steel girder bridges was considered. The emphasis was focused on the parametric analyses of corroded steel girder bridges under two alternatives: (a) when steel bridge girder washing is performed according to a particular frequency, and (b) when no bridge washing is performed to the girders. The reduction of structural capacity was observed for both alternatives along the structure service life, estimated at 100 years. An economic analysis, using the Life-Cycle Cost Analysis method, demonstrated that it is more cost-effective to perform steel girder washing as a scheduled maintenance activity in contrast to the no washing alternative.

Strength monitoring of bridge constructions and features of its application. Part 2. Continuous monitoring of bridge construction status

Directory of Open Access Journals (Sweden)

Ovchinnikov Igor Georgievich

2014-06-01

Full Text Available The article describes a system of continuous monitoring of bridge constructions — a system of observation over the operating conditions and behavior of the bridge structure, which is aimed at ensuring the preservation of its functional application properties within the specified limits, realized on the continuous, long-term basis with the use of instrumentation and ensures on-line presentation of information on the status of structure. To illustrate, one may consider the existing systems of continuous monitoring for a number of bridge constructions in the United States, Japan, Europe, South Korea, Greece and Russia. The article suggests to examine the systems of continuous monitoring of «Commodore John Barry» truss bridge, «Akashi-Kaikyo» suspension bridge, «Siggenthal» reinforced-concrete arch bridge, «Nimhe» suspension bridge, «Jindo»cable-stayed bridge, «Yandzhon» suspension bridge, «Banghwa» bridge, «Seohae» bridge and «Rio-Antirrio» bridge. In addition one may consider monitoring of the longitudinal launching of the bridge superstructures over the Volga River near the village Pristannoye in Saratov region. Finally, it was drawn the conclusion that monitoring of bridge constructions from the standpoint of their consumers is aimed at solving such important problems as preservation of bridge structures, increase in service life of bridge structures through timely detection of faults and their elimination, as well as preservation of bridge structure carrying capacity by controlling their behavior during the operation and improving the efficiency of expenditure of monetary resources for repair activities by correct determination of time and type of the necessary repair.

Field performance of timber bridges. 15, Pueblo County, Colorado, stress-laminated deck bridge

Science.gov (United States)

L. E. Hislop

The Pueblo County 204B bridge was constructed in March 1990 in Pueblo, Colorado, as a demonstration bridge under the USDA Forest Service Timber Bridge Initiative. The stress-laminated deck superstructure is approximately 10 m long, 9 m wide, and 406 mm deep, with a skew of 10 degrees. Performance monitoring was conducted for 3 years, beginning at...

The role of iron(II) dilution in the magnetic and photomagnetic properties of the series [Fe(x)Zn(1-x)(bpp)₂](NCSe)₂.

Science.gov (United States)

Baldé, Chérif; Desplanches, Cédric; Le Gac, Fréderic; Guionneau, Philippe; Létard, Jean-François

2014-06-07

The effects of metal dilution on the spin-crossover behavior of iron(II) in the mixed crystal series [Fe(x)Zn(1-x)(bpp)2](NCSe)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) have been studied using magnetic susceptibility, photomagnetism and diffuse reflectivity measurements. For each mixed-crystal system, the thermal spin transition temperature, T(1/2), and the relaxation temperature of the photo-induced high-spin state, T(LIESST), have been systematically determined. It appears that T(1/2) decreases with the metal dilution while T(LIESST) remains unchanged. Dilution also tends to decrease the hysteresis width and smooth the transition curves. These effects were discussed first qualitatively and then quantitatively on the basis of a kinetic study governing the photo-induced back conversion taking into account the relative sizes of Zn(II) and Fe(II) ions. Interestingly, single crystals were obtained for [Fe(0.6)Zn(0.4)(bpp)2](NCSe)2 allowing the X-ray diffraction crystal-structure determination.

Principles of Bridge Reliability

DEFF Research Database (Denmark)

Thoft-Christensen, Palle; Nowak, Andrzej S.

The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated......, and as an example the reliability profile and a sensitivity analyses for a corroded reinforced concrete bridge is shown....

Design and construction of superstructure in prestressed concrete cable-stayed bridge. ; Aomori Bay Bridge. PC shachokyo jobuko no sekkei to seko. ; Aomori Bay Bridge

Energy Technology Data Exchange (ETDEWEB)

Ishibashi, T.; Fujimori, S.; Oba, M.; Tsuyoshi, T. (East Japan Railway Co., Tokyo (Japan))

1991-12-01

Aomori Bay Bridge is a 1,219m long elevated bridge, a part of No.2 Bay Highway of 1,993m in total length crossing over Aomori railway station which was planned in ordecr to integrate the port facilities of Aomori Harbor and expedite cargo traffic smoothly. Of this Bay Bridge, its main bridge portion crossing over Aomori railway station and the sea area was planned as a continuous prestressed concrete cable-stayed bridge of 498m in total length and consisting of three portions including the central portion in which the main span between the central bridge piers was 240m. It is scheduled to open in the summer of 1992. With regard to the design of this bridge, special care for the view of the bridge has been taken covering from the structure style to the accessories. For this bridge, a large scale underground continuous wall solid base with a box-shaped section consisting of 6 chambers was adopted for the base of a main tower. It has the cantilever suspension structure of the wide girder with the inverted Y-shaped pylons. For its stav cable, was adopted a large capacity stay cable with standard tensile strength of 1,942 fabricated on the site and for its covering tube, a FRP tube was adopted. In this article, the construction of the main girder and stay cables, and the construction control during their installation by projection are reported. 7 refs., 14 figs., 9 tabs.

Impact Coefficient Analysis of Long-Span Railway Cable-Stayed Bridge Based on Coupled Vehicle-Bridge Vibration

Directory of Open Access Journals (Sweden)

Yongle Li

2015-01-01

Full Text Available Compared with medium and small span bridges, very limited attention has been paid on the research of the impact coefficient of long-span railway bridges. To estimate the impact effects of long-span railway bridges subjected to moving vehicles, a real long-span railway cable-stayed bridge is regarded as the research object in this study, and a coupled model of vehicle-bridge system is established. The track irregularities are taken as the system excitation and the dynamic responses of the vehicle-bridge system are calculated. The impact effects on main girder, stayed cable, bearings, and bridge tower are discussed at various vehicle speeds. The results show that different components of the long-span railway cable-stayed bridge have different impact coefficients. Even for each part, the impact coefficient is also different at different local positions. It reveals that the impact coefficients in the actual situation may have significant differences with the related code clauses in the present design codes.

Double Super-Exchange in Silicon Quantum Dots Connected by Short-Bridged Networks

Science.gov (United States)

Li, Huashan; Wu, Zhigang; Lusk, Mark

2013-03-01

Silicon quantum dots (QDs) with diameters in the range of 1-2 nm are attractive for photovoltaic applications. They absorb photons more readily, transport excitons with greater efficiency, and show greater promise in multiple-exciton generation and hot carrier collection paradigms. However, their high excitonic binding energy makes it difficult to dissociate excitons into separate charge carriers. One possible remedy is to create dot assemblies in which a second material creates a Type-II heterojunction with the dot so that exciton dissociation occurs locally. This talk will focus on such a Type-II heterojunction paradigm in which QDs are connected via covalently bonded, short-bridge molecules. For such interpenetrating networks of dots and molecules, our first principles computational investigation shows that it is possible to rapidly and efficiently separate electrons to QDs and holes to bridge units. The bridge network serves as an efficient mediator of electron superexchange between QDs while the dots themselves play the complimentary role of efficient hole superexchange mediators. Dissociation, photoluminescence and carrier transport rates will be presented for bridge networks of silicon QDs that exhibit such double superexchange. This material is based upon work supported by the Renewable Energy Materials Research Science and Engineering Center (REMRSEC) under Grant No. DMR-0820518 and Golden Energy Computing Organization (GECO).

Field performance of timber bridges. 8, Lynches Woods Park stress-laminated deck bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter; D. Conger

The Lynches Woods Park bridge was constructed during the summer of 1990 in Newberry, South Carolina. It is a single-span, single-lane, stress-laminated deck superstructure that measures approximately 30 ft long, 16 ft wide, and 14 in. deep. The bridge is unique in that is one of the first known stress-laminated deck bridges to be constructed of Southern Pine lumber...

Salt-bridge energetics in halophilic proteins.

Science.gov (United States)

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

2014-01-01

Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1) exceeds than that of bridge term (-7 kcal mol-1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its

Golden Gate Bridge response: a study with low-amplitude data from three earthquakes

Science.gov (United States)

Çelebi, Mehmet

2012-01-01

The dynamic response of the Golden Gate Bridge, located north of San Francisco, CA, has been studied previously using ambient vibration data and finite element models. Since permanent seismic instrumentation was installed in 1993, only small earthquakes that originated at distances varying between ~11 to 122 km have been recorded. Nonetheless, these records prompted this study of the response of the bridge to low amplitude shaking caused by three earthquakes. Compared to previous ambient vibration studies, the earthquake response data reveal a slightly higher fundamental frequency (shorter-period) for vertical vibration of the bridge deck center span (~7.7–8.3 s versus 8.2–10.6 s), and a much higher fundamental frequency (shorter period) for the transverse direction of the deck (~11.24–16.3 s versus ~18.2 s). In this study, it is also shown that these two periods are dominant apparent periods representing interaction between tower, cable, and deck.

Bridge the Gap

DEFF Research Database (Denmark)

Marselis, Randi

2017-01-01

This article focuses on photo projects organised for teenage refugees by the Society for Humanistic Photography (Berlin, Germany). These projects, named Bridge the Gap I (2015), and Bridge the Gap II (2016), were carried out in Berlin and brought together teenagers with refugee and German...

Bridge technology report

CERN Document Server

2013-01-01

Please note this is a Short Discount publication. As LANs have proliferated, new technologies and system concepts have come to the fore. One of the key issues is how to interconnect networks. One means of interconnection is to use a 'bridge'. Other competing technologies are repeaters, routers, and gateways. Bridges permit traffic isolation, connect network segments together and operate at the MAC layer. Further, because they operate at the MAC layer, they can handle a variety of protocols such as TCP/IP, SNA, and X.25. This report focuses on the specific technology of bridging two netw

Field performance of timber bridges. 12, Christian Hollow stress-laminated box-beam bridge

Science.gov (United States)

J. P. Wacker; S. C. Catherman; R. G. Winnett

In January 1992, the Christian Hollow bridge was constructed in Steuben County, New York. The bridge is a single-span, stress-laminated box-beam superstructure that is 9.1 m long, 9.8 m wide, and 502 mm deep (30 ft long, 32 ft wide, and 19-3/4 in. deep). The performance of the bridge was continuously monitored for 28 months, beginning shortly after installation....

Pilot Study for Investigating the Cyclic Response of the Recentering Bridge Bearing System Combined with the Friction Damper

Directory of Open Access Journals (Sweden)

Jong Wan Hu

2016-01-01

Full Text Available The bridge bearing is one of the component members which provide resting supports between piers and decks. The bridge bearing is intended to control longitudinal movement caused by traffic flow and thermal expansion, thereby reducing stress concentration. In high seismicity area, the bridge bearing has been utilized as the base isolation system to mitigate acceleration transferred from the ground. Although the existing bridge bearing installed between superstructure and substructure provides extra flexibility to the base of the entire structure, considerable permanent deformation occurs due to lack of recentering capacity after earthquake. It is required to spend extra cost for repairing impaired parts. The bridge bearings integrated with superelastic shape memory alloy (SMA devices used for upgrading the recentering effect into the friction damper are proposed in this study. The refined finite element (FE analyses are introduced to reproduce the response of such new structures under cyclic loading condition. The bridge bearing systems that maintain uniform recentering capability are designed with various friction coefficients so as to examine energy dissipation and residual deformation through FE analyses. After observing FE analysis results, optimal design for the recentering bridge bearing system will be proposed to take advantage of energy dissipation and self-centering capacity.

Road Bridges and Culverts, Bridge dataset only includes bridges maintained by Johnson County Public Works in the unincorporated areas, Published in Not Provided, Johnson County Government.

Data.gov (United States)

NSGIC Local Govt | GIS Inventory — Road Bridges and Culverts dataset current as of unknown. Bridge dataset only includes bridges maintained by Johnson County Public Works in the unincorporated areas.

Predicting critical temperatures of iron(II) spin crossover materials: Density functional theory plus U approach

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yachao, E-mail: yczhang@nano.gznc.edu.cn [Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Normal College, Guiyang 550018, Guizhou (China)

2014-12-07

A first-principles study of critical temperatures (T{sub c}) of spin crossover (SCO) materials requires accurate description of the strongly correlated 3d electrons as well as much computational effort. This task is still a challenge for the widely used local density or generalized gradient approximations (LDA/GGA) and hybrid functionals. One remedy, termed density functional theory plus U (DFT+U) approach, introduces a Hubbard U term to deal with the localized electrons at marginal computational cost, while treats the delocalized electrons with LDA/GGA. Here, we employ the DFT+U approach to investigate the T{sub c} of a pair of iron(II) SCO molecular crystals (α and β phase), where identical constituent molecules are packed in different ways. We first calculate the adiabatic high spin-low spin energy splitting ΔE{sub HL} and molecular vibrational frequencies in both spin states, then obtain the temperature dependent enthalpy and entropy changes (ΔH and ΔS), and finally extract T{sub c} by exploiting the ΔH/T − T and ΔS − T relationships. The results are in agreement with experiment. Analysis of geometries and electronic structures shows that the local ligand field in the α phase is slightly weakened by the H-bondings involving the ligand atoms and the specific crystal packing style. We find that this effect is largely responsible for the difference in T{sub c} of the two phases. This study shows the applicability of the DFT+U approach for predicting T{sub c} of SCO materials, and provides a clear insight into the subtle influence of the crystal packing effects on SCO behavior.

Laboratory Testing of Precast Bridge Beck Panel Transverse Connections for Use in Accelerated Bridge Construction

OpenAIRE

Porter, Scott D.

2009-01-01

Precast concrete bridge deck panels have been used for decades to accelerate bridge construction. Cracking of the transverse connection between panels is a common problem that can damage deck overlays and cause connection leaking leading to corrosion of lower bridge elements. To better understand the behavior of bridge deck transverse female-to-female connections, shear and moment lab testing were performed at Utah State University for the Utah Department of Transportation. Two existing UDOT ...

Human Errors and Bridge Management Systems

DEFF Research Database (Denmark)

Thoft-Christensen, Palle; Nowak, A. S.

on basis of reliability profiles for bridges without human errors are extended to include bridges with human errors. The first rehabilitation distributions for bridges without and with human errors are combined into a joint first rehabilitation distribution. The methodology presented is illustrated...... for reinforced concrete bridges....

A bridge with a view, a view with a bridge : Identifying design considerations for bridges to strengthen regional identity

NARCIS (Netherlands)

Smits, J.E.P.; van der Hoeven, F.D.

2015-01-01

This paper discusses design considerations for creating high quality infrastructural artefacts with an emphasis on bridges. The authors pursue a design study and analysis approach to highlight the specifics of infrastructure design for regional identity, based on their own work on a bridge

Precast concrete elements for accelerated bridge construction : laboratory testing, field testing, evaluation of a precast concrete bridge, Madison County bridge.

Science.gov (United States)

2009-01-01

The importance of rapid construction technologies has been recognized by the Federal Highway Administration (FHWA) and the Iowa : DOT Office of Bridges and Structures. Recognizing this a two-lane single-span precast box girder bridge was constructed ...

On the role of non-bridging oxygen centers in the red luminescence emission from silicon nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Borsella, Elisabetta; D' Amato, Rosaria; Fabbri, Fabio [ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Falconieri, Mauro [ENEA, C. R. Casaccia, via Anguillarese 301, 00123 Roma (Italy); Trave, Enrico [Physical Chemistry Department, Universita Ca' Foscari Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Bello, Valentina; Mattei, Giovanni [Physics Department, Universita degli Studi di Padova, Via Marzolo 8, 35131 Padova (Italy); Nie, Yaru; Wang, Dayang [Max Planck Institute of Colloids and Interfaces, 14424 Potsdam (Germany)

2011-03-15

The process responsible for visible-near infrared luminescence emission in Si nanostructures has been generating significant controversy for years. The debate has focused on whether light emission is originated by recombination of quantum confined excitons or by defects located at the surface. It is experimentally difficult to distinguish the two contributions since both are size-dependent. Moreover, all the studies were performed on different systems and consequently the comparisons were not free from ambiguities. Here we relate the spectroscopic properties of pyrolytic Si nanocrystals, aged in air, and after complete conversion to amorphous silica by alkali etching-assisted oxidation. The strong resemblance of the spectral and time decay behavior of the red PL emission in both systems (surface oxidized nanocrystalline Si and amorphous silica sample) indicates that this emission is dominated by defects in the silicon oxide. The strongly non-exponential time behavior of the photo-luminescence emission in both systems can be modeled as the sum of exponential decays from the emitting defects, thus ruling out the interpretation in terms of the so-called ''stretched exponential'' decay. Using this model we also obtained the emission energy and inhomogeneous linewidth of the luminescent defects, allowing us to identify them as the non-bridging oxygen hole centers. The emission energy of these defects depends strongly on their physical and chemical environment and can produce a shift apparently due to the size effect. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

BUILDING A BETTER GLUTEAL BRIDGE: ELECTROMYOGRAPHIC ANALYSIS OF HIP MUSCLE ACTIVITY DURING MODIFIED SINGLE-LEG BRIDGES.

Science.gov (United States)

Lehecka, B J; Edwards, Michael; Haverkamp, Ryan; Martin, Lani; Porter, Kambry; Thach, Kailey; Sack, Richard J; Hakansson, Nils A

2017-08-01

Gluteal strength plays a role in injury prevention, normal gait patterns, eliminating pain, and enhancing athletic performance. Research shows high gluteal muscle activity during a single-leg bridge compared to other gluteal strengthening exercises; however, prior studies have primarily measured muscle activity with the active lower extremity starting in 90 ° of knee flexion with an extended contralateral knee. This standard position has caused reports of hamstring cramping, which may impede optimal gluteal strengthening. The purpose of this study was to determine which modified position for the single-leg bridge is best for preferentially activating the gluteus maximus and medius. Cross-Sectional. Twenty-eight healthy males and females aged 18-30 years were tested in five different, randomized single-leg bridge positions. Electromyography (EMG) electrodes were placed on subjects' gluteus maximus, gluteus medius, rectus femoris, and biceps femoris of their bridge leg (i.e., dominant or kicking leg), as well as the rectus femoris of their contralateral leg. Subjects performed a maximal voluntary isometric contraction (MVIC) for each tested muscle prior to performing five different bridge positions in randomized order. All bridge EMG data were normalized to the corresponding muscle MVIC data. A modified bridge position with the knee of the bridge leg flexed to 135 ° versus the traditional 90 ° of knee flexion demonstrated preferential activation of the gluteus maximus and gluteus medius compared to the traditional single-leg bridge. Hamstring activation significantly decreased (p bridge by flexing the active knee to 135 ° instead of 90 ° minimizes hamstring activity while maintaining high levels of gluteal activation, effectively building a bridge better suited for preferential gluteal activation. 3.

The violin bridge as filter.

Science.gov (United States)

Bissinger, George

2006-07-01

The violin bridge filter role was investigated using modal and acoustic measurements on 12 quality-rated violins combined with systematic bridge rocking frequency f(rock) and wing mass decrements deltam on four bridges for two other violins. No isolated bridge resonances were observed; bridge motions were complex (including a "squat" mode near 0.8 kHz) except for low frequency rigid body pivot motions, all more or less resembling rocking motion at higher frequencies. A conspicuous broad peak near 2.3 kHz in bridge driving point mobility (labeled BH) was seen for good and bad violins. Similar structure was seen in averaged bridge, bridge feet, corpus mobilities and averaged radiativity. No correlation between violin quality and BH driving point, averaged corpus mobility magnitude, or radiativity was found. Increasing averaged-over-f(rock) deltam(g) from 0 to 0.12 generally increased radiativity across the spectrum. Decreasing averaged-over-deltam f(rock) from 3.6 to 2.6 kHz produced consistent decreases in radiativity between 3 and 4.2 kHz, but only few-percent decreases in BH frequency. The lowest f(rock) values were accompanied by significantly reduced radiation from the Helmholtz A0 mode near 280 Hz; this, combined with reduced high frequency output, created overall radiativity profiles quite similar to "bad" violins among the quality-rated violins.

Injuries sustained after falls from bridges across the United States-Mexico border at El Paso.

Science.gov (United States)

McLean, Susan F; Tyroch, Alan H

2012-05-01

To compare demographics and motivations for falls from bridges at the United States-Mexico border and in El Paso County, Texas, and to analyze injuries and injury patterns to support intentionality and to provide treatment recommendations. A retrospective observational review was conducted of hospital admissions to a trauma center after falls from bridges from 1995 to 2009. Statistical methods used were chi-square testing, T-test for means comparison, univariate correlations, and regression analysis. Of the 97 evaluated patients, 81.4% fell from U.S.-Mexico border bridges, including one patient who fell from a railway bridge; 74.7% of those falling from border bridges had a non-U.S. address, contrasting with 22.2% of those who fell within the United States. Falls over the border were associated with more immigration-related motivations and fewer suicide attempts. Injuries included lower extremities in 76 (78.4%) and thoracolumbar spine in 27 (27.8%) patients; 16 patients with a thoracolumbar spine fracture (59.3%) also had a lower extremity injury. Mean hospital length of stay was 7.2 days. Mean injury severity score was 8.45 (range 1-43). Age, injury severity score, and pelvic fracture increased the hospital length of stay. Patients fell while emigrating-immigrating based on residence and motivating factors. A dyad of lower extremity and thoracolumbar spine injuries coincided in 59.3% of those with a thoracolumbar spine injury; thoracolumbar spine imaging of patients evaluated after falls from bridges is recommended. Proposed prevention strategies include posting signs on bridges and installing catch-net safety barriers.

Role of multiprotein bridging factor 1 in archaea: bridging the domains?

NARCIS (Netherlands)

Koning, de B.; Blombach, F.; Wu Hao,; Brouns, S.J.J.; Oost, van der J.

2009-01-01

MBF1 (multiprotein bridging factor 1) is a highly conserved protein in archaea and eukaryotes. It was originally identified as a mediator of the eukaryotic transcription regulator BmFTZ-F1 (Bombyx mori regulator of fushi tarazu). MBF1 was demonstrated to enhance transcription by forming a bridge

23 CFR 650.809 - Movable span bridges.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Movable span bridges. 650.809 Section 650.809 Highways 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...

Sustainable Bridge Infrastructure Procurement

DEFF Research Database (Denmark)

Safi, Mohammed; Du, Guangli; Simonsson, Peter

2016-01-01

The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use...... to procure the most “sustainable” (lifecycle-efficient) bridge through a fair design-build (D-B) tendering process, considering all the main aspects: life-cycle cost (LCC), service life-span, aesthetic demands and environmental impacts (LCA)....

Nonlinearity in oscillating bridges

Directory of Open Access Journals (Sweden)

Filippo Gazzola

2013-09-01

Full Text Available We first recall several historical oscillating bridges that, in some cases, led to collapses. Some of them are quite recent and show that, nowadays, oscillations in suspension bridges are not yet well understood. Next, we survey some attempts to model bridges with differential equations. Although these equations arise from quite different scientific communities, they display some common features. One of them, which we believe to be incorrect, is the acceptance of the linear Hooke law in elasticity. This law should be used only in presence of small deviations from equilibrium, a situation which does not occur in widely oscillating bridges. Then we discuss a couple of recent models whose solutions exhibit self-excited oscillations, the phenomenon visible in real bridges. This suggests a different point of view in modeling equations and gives a strong hint how to modify the existing models in order to obtain a reliable theory. The purpose of this paper is precisely to highlight the necessity of revisiting the classical models, to introduce reliable models, and to indicate the steps we believe necessary to reach this target.

Coupling vibration research on Vehicle-bridge system

Science.gov (United States)

Zhou, Jiguo; Wang, Guihua

2018-01-01

The vehicle-bridge coupling system forms when vehicle running on a bridge. It will generate a relatively large influence on the driving comfort and driving safe when the vibration of the vehicle is bigger. A three-dimensional vehicle-bridge system with biaxial seven degrees of freedom has been establish in this paper based on finite numerical simulation. Adopting the finite element transient numerical simulation to realize the numerical simulation of vehicle-bridge system coupling vibration. Then, analyze the dynamic response of vehicle and bridge while different numbers of vehicles running on the bridge. Got the variation rule of vertical vibration of car body and bridge, and that of the contact force between the wheel and bridge deck. The research results have a reference value for the analysis about the vehicle running on a large-span cabled bridge.

Nondestructive testing for bridge diagnosis

International Nuclear Information System (INIS)

Oshima, Toshiyuki; Mikami, Shuichi; Yamazaki, Tomoyuki

1997-01-01

There are many motivations for bridge diagnosis using Nondestructive testing (NDT) to monitor its integrity. The measured frequency and damping on real bridge are compared in one figure as a function of span length and general aspects are explained. These date were measured in every construction of bridges and applied to design new bridges. Ultrasonic testing is also well used for concrete and steel members mainly to detect internal damages or delaminations. Detail analysis on reflected waves gives us more accurate information about the defect. Experimental results are shown as examples in this paper.

Salt bridges: geometrically specific, designable interactions.

Science.gov (United States)

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

2011-03-01

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, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on 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. Copyright © 2010 Wiley-Liss, Inc.

An Expert System for Concrete Bridge Management

DEFF Research Database (Denmark)

Brito, J. de; Branco, F. A.; Thoft-Christensen, Palle

1997-01-01

The importance of bridge repair versus new bridge construction has risen in recent decades due to high deterioration rates that have been observed in these structures. Budgets both for building new bridges and keeping the existing ones are always limited. To help rational decision-making, bridge...... management systems are presently being implemented by bridge authorities in several countries. The prototype of an expert system for concrete bridge management is presented in this paper, with its functionality relying on two modules. The inspection module relies on a periodic acquisition of field...... information complemented by a knowledge-based interactive system, BRIDGE-1. To optimize management strategies at the headquarters, the BRIDGE-2 module was implemented, including three submodules: inspection strategy, maintenance and repair....

Model predictive control for a dual active bridge inverter with a floating bridge

OpenAIRE

Chowdhury, Shajjad; Wheeler, Patrick W.; Gerada, C.; Patel, Chintan

2016-01-01

This paper presents a Model Predictive Control technique applied to a dual active bridge inverter where one of the bridges is floating. The proposed floating bridge topology eliminates the need for isolation transformer in a dual inverter system and therefore reduces the size, weight and losses in the system. To achieve multilevel output voltage waveforms the floating inverter DC link capacitor is charged to the half of the main DC link voltage. A finite-set Model Predictive Control technique...

Bridge over troubled water?

DEFF Research Database (Denmark)

Svendsen, Gunnar Lind Haase; Nannestad, Peter; Svendsen, Gert Tinggaard

2008-01-01

The problem of integrating non-Western immigrants into Western welfare states is the focus of this paper. To address this issue, we suggest a social capital approach in which we apply the conceptual pair of bridging social capital (BR), which connects an individual to the broader social structure...... relationship between the levels of bridging and bonding capital, suggesting that bonding social capital in the immigrant group does not seem to impede the establishment of the bridging social capital needed for integration....

Bridge and steel structures. History and vision on bridge erection; Kyoryo kokozobutsu. Kasetsu gijutsu no shorai

Energy Technology Data Exchange (ETDEWEB)

Mukai, S.; Hayashi, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

1998-08-20

This paper describes the progress of bridge erection technology. It introduces the results of cable erection, rotated/extruded erection, and cantilever erection. The cable erection is a multi point suspension erection using cables. For the rotated/extruded erection, the monolithic construction is conducted on a working yard set in a right angle to the construction position, and the horizontal beams of the bridge piers (corbel girders) are constructed by the rotated method using a slewing base incorporated around the bridge piers at one side. For the construction of stiffening girders of Innoshima-ohashi Bridge of Honshu-Shikoku Joint Bridge in 1978, trussed face bar blocks were extruded from the main tower in order using a travel crane. For the suspension bridges and cable stayed bridges, main towers were erected using various types of cranes. The erection of Tamashima-ohashi Bridge with a weight of 500 ton using an offshore floating crane is introduced as a large block method. Analysis methods and measurement techniques at the site are used in order to analyze the shape in each step under the erection and to ensure the accurate final complete shape. Reduction of the construction cost, improvement of erection technology, and technology development for large-scale projects are subjects in the future. 22 refs., 8 figs., 1 tab.

An orthogonal ferromagnetically coupled tetracopper(II) 2 x 2 homoleptic grid supported by micro-O4 bridges and its DFT study.

Science.gov (United States)

Roy, Somnath; Mandal, Tarak Nath; Barik, Anil Kumar; Pal, Sachindranath; Butcher, Ray J; El Fallah, Mohamed Salah; Tercero, Javier; Kar, Susanta Kumar

2007-03-28

A pyrazole based ditopic ligand (PzOAP), prepared by the reaction between 5-methylpyrazole-3-carbohydrazide and methyl ester of imino picolinic acid, reacts with Cu(NO3)2.6H2O to form a self-assembled, ferromagnetically coupled, alkoxide bridged tetranuclear homoleptic Cu(II) square grid-complex [Cu4(PzOAP)4(NO3)2] (NO3)2.4H2O (1) with a central Cu4[micro-O4] core, involving four ligand molecules. In the Cu4[micro-O4] core, out of four copper centers, two copper centers are penta-coordinated and the remaining two are hexa-coordinated. In each case of hexa-coordination, the sixth position is occupied by the nitrate ion. The complex 1 has been characterized structurally and magnetically. Although Cu-O-Cu bridge angles are too large (138-141 degrees) and Cu-Cu distances are short (4.043-4.131 A), suitable for propagation of expected antiferromagnetic exchange interactions within the grid, yet intramolecular ferromagnetic exchange (J = 5.38 cm(-1)) is present with S = 4/2 magnetic ground state. This ferromagnetic interaction is quite obvious from the bridging connections (d(x2-y2)) lying almost orthogonally between the metal centers. The exchange pathways parameters have been evaluated from density functional calculations.

GFRP seismic strengthening and structural heath monitoring of Portage Creek Bridge concrete columns

International Nuclear Information System (INIS)

Huffman, S.; Bagchi, A.; Mufti, A.; Neale, K.; Sargent, D.; Rivera, E.

2006-01-01

Located in Victoria British Columbia (BC), Canada, the Portage Creek Bridge is a 124m long, three-span structure with a reinforced concrete piers and abutments on H piles. The bridge was designed prior to the introduction of current bridge seismic design codes and construction practices. Therefore it was not designed to resist the earthquake forces as required by today's standards. The bridge is on a route classified as a Municipal Disaster Route scheduled to be retrofitted to prevent collapse during a design seismic event, with a return period of 475 years (i.e., an event with 105 probability of exceedance in 50 years). Conventional materials and methods were used to retrofit most of the bridge. The dynamic analysis of the bridge predicted the two tall columns of Pier No. 1 will form plastic hinges under an earthquake resulting an additional shear to the short columns of Pier No. 2. A non-liner static pushover analysis indicated the short columns will not be able to form plastic hinges prior to failure in shear. The innovative solution of Fiber Reinforced Polymer wraps (FRPs) was chosen to strengthen the short columns for shear without increasing the moment capacity. The FRP wraps and the bridge were instrumented as one of 36 demonstration projects across Canada sponsored by ISIS (Intelligent Sensing for Innovative Structure) Canada, federally funded Network of Centers of Excellence, to access the performance of FRP and the use of FOS (Fiber Optic Sensors) for Structural Health Monitoring (SHM). The two columns of the bridge pier were strengthened with GFRP (Glass Fiber Reinforced Polymer) wraps with eight bi-directional rosette type strain gauges and four long gauge fiber optic sensors attached to the outer layer of the wraps. In addition, two 3-D Crossbow accelerometers are installed on the pier cap above the columns and a traffic web-cam mounted above the deck at the pier location. The data is collected through high sped internet line to an interactive web page

Evaluation of high temperature superconductive thermal bridges for space borne cryogenic detectors

Science.gov (United States)

Scott, Elaine P.

1996-01-01

Infrared sensor satellites are used to monitor the conditions in the earth's upper atmosphere. In these systems, the electronic links connecting the cryogenically cooled infrared detectors to the significantly warmer amplification electronics act as thermal bridges and, consequently, the mission lifetimes of the satellites are limited due to cryogenic evaporation. High-temperature superconductor (HTS) materials have been proposed by researchers at the National Aeronautics and Space Administration Langley's Research Center (NASA-LaRC) as an alternative to the currently used manganin wires for electrical connection. The potential for using HTS films as thermal bridges has provided the motivation for the design and the analysis of a spaceflight experiment to evaluate the performance of this superconductive technology in the space environment. The initial efforts were focused on the preliminary design of the experimental system which allows for the quantitative comparison of superconductive leads with manganin leads, and on the thermal conduction modeling of the proposed system. Most of the HTS materials were indicated to be potential replacements for the manganin wires. In the continuation of this multi-year research, the objectives of this study were to evaluate the sources of heat transfer on the thermal bridges that have been neglected in the preliminary conductive model and then to develop a methodology for the estimation of the thermal conductivities of the HTS thermal bridges in space. The Joule heating created by the electrical current through the manganin wires was incorporated as a volumetric heat source into the manganin conductive model. The radiative heat source on the HTS thermal bridges was determined by performing a separate radiant interchange analysis within a high-T(sub c) superconductor housing area. Both heat sources indicated no significant contribution on the cryogenic heat load, which validates the results obtained in the preliminary conduction

Dragon bridge - the world largest dragon-shaped (ARCH steel bridge as element of smart city

Directory of Open Access Journals (Sweden)

Chinh Luong Minh

2016-01-01

Full Text Available Dragon Bridge - The world’s largest dragon-shaped steel bridge, with an installation cost of $85 million USD, features 6 lanes for two separate directions, 666 meters of undulating steel in the shape of a dragon in the Ly Dynasty, the symbol of prosperity in Vietnamese culture. This unique and beautifully lit bridge, which also breathes fire and sprays water. It’s the purposeful integration of the lighting hardware articulates the dragon’s form, and the fire-breathing dragon head. This project transcends the notion of monumental bridge with dynamic colour-changing lighting, creating an iconic sculpture in the skyline that is both reverent and whimsical. The signature feature of the bridge was the massive undulating support structure resembling a dragon flying over the river. The dragon is prominent in Vietnamese culture as a symbol of power and nobility. Dragon Bridge stands out as a model of innovation. It has received worldwide attention in the design community and from the global media for its unique arch support system. Dragon Bridge serves as an example of how aesthetic quality of a design can serve cultural, economic and functional purposes. The article presents design solutions of the object and the evaluation of the technical condition before putting the facility into service.

Experimental investigation of different fill materials in arch bridges with particular focus on Pearl-Chain Bridges

DEFF Research Database (Denmark)

Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Hertz, Kristian Dahl

2016-01-01

Pearl-Chain Bridge technology is a recently developed prefabricated arch solution for road and railway bridges allowing faster, more environmentally friendly, and cheaper bridge construction. This study compared the strength and durability properties of three different types of fill material...

Bridge element deterioration rates.

Science.gov (United States)

2008-10-01

This report describes the development of bridge element deterioration rates using the NYSDOT : bridge inspection database using Markov chains and Weibull-based approaches. It is observed : that Weibull-based approach is more reliable for developing b...

Bridge-Vehicle Impact Assessment

Science.gov (United States)

2011-08-01

Bridges in New York State have been experiencing close to 200 bridge hits a year. These : accidents are attributed to numerous factors including: improperly stored equipment on trucks; : violation of vehicle posting signs; illegal commercial vehicles...

Bridge vehicle impact assessment.

Science.gov (United States)

2011-12-01

Bridges in New York State have been experiencing close to 200 bridge hits a year. These : accidents are attributed to numerous factors including: improperly stored equipment on trucks; : violation of vehicle posting signs; illegal commercial vehicles...

Wireless Smart Sensor Network System Using SmartBridge Sensor Nodes for Structural Health Monitoring of Existing Concrete Bridges

Science.gov (United States)

Gaviña, J. R.; Uy, F. A.; Carreon, J. D.

2017-06-01

There are over 8000 bridges in the Philippines today according to the Department of Public Works and Highways (DPWH). Currently, visual inspection is the most common practice in monitoring the structural integrity of bridges. However, visual inspections have proven to be insufficient in determining the actual health or condition of a bridge. Structural Health Monitoring (SHM) aims to give, in real-time, a diagnosis of the actual condition of the bridge. In this study, SmartBridge Sensor Nodes were installed on an existing concrete bridge with American Association of State Highway and Transportation Officials (AASHTO) Type IV Girders to gather vibration of the elements of the bridge. Also, standards on the effective installation of SmartBridge Sensor Nodes, such as location and orientation was determined. Acceleration readings from the sensor were then uploaded to a server, wherein they are monitored against certain thresholds, from which, the health of the bridge will be derived. Final output will be a portal or webpage wherein the information, health, and acceleration readings of the bridge will be available for viewing. With levels of access set for different types of users, the main users will have access to download data and reports. Data transmission and webpage access are available online, making the SHM system wireless.

Horizontal bridges in polar dielectric liquids

Science.gov (United States)

Woisetschläger, Jakob; Wexler, Adam D.; Holler, Gert; Eisenhut, Mathias; Gatterer, Karl; Fuchs, Elmar C.

2012-01-01

When a high-voltage direct-current is applied to two beakers filled with polar liquid dielectrica like water or methanol, a horizontal bridge forms between the two beakers. By repeating a version of Pellat's experiment, it is shown that a horizontal bridge is stable by the action of electrohydrodynamic pressure. Thus, the static and dynamic properties of the phenomenon called a `floating water bridge' can be explained by the gradient of Maxwell pressure, replenishing the liquid within the bridge against any drainage mechanism. It is also shown that a number of liquids can form stable and long horizontal bridges. The stability of such a connection, and the asymmetry in mass flow through such bridges caused by the formation of ion clouds in the vicinity of the electrodes, is also discussed by two further experiments.

LTBP bridge performance primer.

Science.gov (United States)

2013-12-01

"The performance of bridges is critical to the overall performance of the highway transportation system in the United States. However, many critical aspects of bridge performance are not well understood. The reasons for this include the extreme diver...

Synthesis, X-ray and Mössbauer study of iron(II) complexes with trithiocyanuric acid (ttcH3). The X-ray structures of [Fe(bpy)3](ttcH) • 2bpy • 7H2O and [Fe(phen)3](ttcH2)(ClO4) • 2CH3OH • 2H2O

Czech Academy of Sciences Publication Activity Database

Kopel, P.; Trávníček, Zdeněk; Zbořil, R.; Mrozinski, J.

2004-01-01

Roč. 23, č. 14 (2004), s. 2193-2202 ISSN 0277-5387 R&D Projects: GA ČR(CZ) GA203/02/0436 Grant - others:GA MŠk1(CZ) MSM 153100007 Institutional research plan: CEZ:AV0Z5038910 Keywords : Iron(II) complexes * Trithiocyanuric acid * Mössbauer spectra * Crystal structures Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.586, year: 2004

33 CFR 115.70 - Advance approval of bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Advance approval of bridges. 115... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.70 Advance approval of bridges. (a) The General Bridge Act of 1946 requires the approval of the location and plans of bridges prior...

Numerical analysis of dynamic response of vehicle–bridge coupled system on long-span continuous girder bridge

Directory of Open Access Journals (Sweden)

Lipeng An

2016-07-01

Full Text Available To systematically study the vehicle–bridge coupled dynamic response and its change rule with different parameters, a vehicle model with seven degrees of freedom was built and the total potential energy of vehicle space vibration system was deduced. Considering the stimulation of road roughness, the dynamic response equation of vehicle–bridge coupled system was established in accordance with the elastic system principle of total potential energy with stationary value and the “set-in-right-position” rule. On the basis of the self-compiled Fortran program and bridge engineering, the dynamic response of long-span continuous girder bridge under vehicle load was studied. This study also included the calculation of vehicle impact coefficient, evaluation of vibration comfort, and analysis of dynamic response parameters. Results show the impact coefficient changes with lane number and is larger than the value calculated by the “general code for design of highway bridges and culverts (China”. The Dieckmann index of bridge vibration is also related to lane number, and the vibration comfort evaluation is good in normal conditions. The relevant conclusions from parametric analyses have practical significance to dynamic design and daily operation of long-span continuous girder bridges in expressways. Safety and comfort are expected to improve significantly with further control of the vibration of vehicle–bridge system.

Bridge Scour Technology Transfer

Science.gov (United States)

2018-01-24

Scour and flooding are the leading causes of bridge failures in the United States and therefore should be monitored. New applications of tools and technologies are being developed, tested, and implemented to reduce bridge scour risk. The National Coo...

Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

Energy Technology Data Exchange (ETDEWEB)

Keates, Adam C. [School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1B,. UK (United Kingdom); Wang, Qianlong [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom); Weller, Mark T., E-mail: m.t.weller@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom)

2014-02-15

Single crystal and bulk polycrystalline forms of K{sub 2}MP{sub 2}O{sub 7} (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42{sub 1}m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP{sub 2}O{sub 7}]{sup 2−} with potassium cations situated between the layers. The MO{sub 4} tetrahedra share oxygen atoms with [P{sub 2}O{sub 7}]{sup 4−} diphosphate groups and the potassium ions have KO{sub 8} square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d{sup 6} Fe(II) and p-orbital mixing or a second order JT effect for d{sup 9} Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K{sub 2}MP{sub 2}O{sub 7}, M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP{sub 2}O{sub 7}]{sup 2−}, formed from linked pyrophosphate groups and MO{sub 4} tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d{sup 6} Fe(II) and p-orbital mixing and second-order JT effects for d{sup 9} Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d{sup 10} distorted coordinations.

Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

International Nuclear Information System (INIS)

Keates, Adam C.; Wang, Qianlong; Weller, Mark T.

2014-01-01

Single crystal and bulk polycrystalline forms of K 2 MP 2 O 7 (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42 1 m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP 2 O 7 ] 2− with potassium cations situated between the layers. The MO 4 tetrahedra share oxygen atoms with [P 2 O 7 ] 4− diphosphate groups and the potassium ions have KO 8 square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d 6 Fe(II) and p-orbital mixing or a second order JT effect for d 9 Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K 2 MP 2 O 7 , M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP 2 O 7 ] 2− , formed from linked pyrophosphate groups and MO 4 tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d 6 Fe(II) and p-orbital mixing and second-order JT effects for d 9 Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d 10 distorted coordinations

Revised Rules for Concrete Bridges

DEFF Research Database (Denmark)

Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.

This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

The stories of two bridges in Ghana

DEFF Research Database (Denmark)

Andreasen, Jørgen

2004-01-01

Public participation in bridge building was promoted by un habitat in the village of Mankrong. The neighbouring village did not participate in the construction of their bridge. The first flooding washed the second bridge down while the "participative bridge" stood up....

The Lederman Science Center: Past, Present, Future

Energy Technology Data Exchange (ETDEWEB)

Bardeen, Marjorie G.; /Fermilab

2011-11-01

For 30 years, Fermilab has offered K-12 education programs, building bridges between the Lab and the community. The Lederman Science Center is our home. We host field trips and tours, visit schools, offer classes and professional development workshops, host special events, support internships and have a strong web presence. We develop programs based on identified needs, offer programs with peer-leaders and improve programs from participant feedback. For some we create interest; for others we build understanding and develop relationships, engaging participants in scientific exploration. We explain how we created the Center, its programs, and what the future holds.

Bridging the Gap

DEFF Research Database (Denmark)

Dahlberg, Rasmus

2016-01-01

The fixed link between Denmark and Sweden connects two busy cities and a large international airport with many of its travelers and employees. 18,000 vehicles and 160 passenger trains transport each day more than 70,000 people across the combined road and rail Øresund Bridge and through the Øresu...... in its final report to the Danish and Swedish transport authorities while drawing upon experiences from two recent comparable cases of infrastructure disruptions: The Champlain Bridge (2009) and the Forth Road Bridge (2015).......The fixed link between Denmark and Sweden connects two busy cities and a large international airport with many of its travelers and employees. 18,000 vehicles and 160 passenger trains transport each day more than 70,000 people across the combined road and rail Øresund Bridge and through the Øresund...... Tunnel, approximately 25,000 of them critical to the regional work market. Even though the risk analysis states that the likelihood of a long-term closure (100C days) is very low Danish and Swedish transport authorities have demanded that the infrastructure operator conducts a survey of the preparedness...

49 CFR 236.766 - Locking, movable bridge.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Locking, movable bridge. 236.766 Section 236.766... Locking, movable bridge. The rail locks, bridge locks, bolt locks, circuit controllers, and electric locks used in providing interlocking protection at a movable bridge. ...

Dynamic assessment of bridge deck performance considering realistic bridge-traffic interaction : research brief

Science.gov (United States)

2017-09-01

This study is to develop simulation methodology to conduct the dynamic assessment of bridge deck performance subjected to traffic. Concrete bridge decks are exposed to daily traffic loads and may experience some surface cracking caused by excessive s...

Development of a precast bridge deck overhang system for the rock creek bridge.

Science.gov (United States)

2008-12-01

Precast, prestressed panels are commonly used at interior beams for bridges in Texas. The use of these : panels provides ease of construction, sufficient capacity, and good economy for the construction of : bridges in Texas. Current practice for the ...

Field performance of timber bridges. 13, Mohawk Canal stress-laminated bridge

Science.gov (United States)

P. D. Hilbrich Lee; X. Lauderdale

The Mohawk Canal bridge was constructed in August 1994, just outside Roll, Arizona. It is a simple-span, double-lane, stress-laminated deck superstructure, approximately 6.4 m (21 ft) long and 10.4 m (34 ft) wide and constructed with Combination 16F-V3 Douglas Fir glued-laminated timber beam laminations. The performance of the bridge was monitored continuously for 2...

Development of inspection robots for bridge cables.

Science.gov (United States)

Yun, Hae-Bum; Kim, Se-Hoon; Wu, Liuliu; Lee, Jong-Jae

2013-01-01

This paper presents the bridge cable inspection robot developed in Korea. Two types of the cable inspection robots were developed for cable-suspension bridges and cable-stayed bridge. The design of the robot system and performance of the NDT techniques associated with the cable inspection robot are discussed. A review on recent advances in emerging robot-based inspection technologies for bridge cables and current bridge cable inspection methods is also presented.

Horizontal bridges in polar dielectric liquids

Energy Technology Data Exchange (ETDEWEB)

Woisetschlaeger, Jakob [Graz University of Technology, Experimental Turbomachinery Research and Optical Measurement Group, Institute for Thermal Turbomachinery and Machine Dynamics, Graz (Austria); Wexler, Adam D.; Fuchs, Elmar C. [Wetsus, Center of Excellence for Sustainable Water Technology, Leeuwarden (Netherlands); Holler, Gert [Graz University of Technology, Institute of Electrical Measurement and Measurement Signal Processing, Graz (Austria); Eisenhut, Mathias [Graz University of Technology, Institute of Analytical Chemistry and Food Chemistry, Graz (Austria); Gatterer, Karl [Graz University of Technology, Institute of Physical and Theoretical Chemistry, Graz (Austria)

2012-01-15

When a high-voltage direct-current is applied to two beakers filled with polar liquid dielectrica like water or methanol, a horizontal bridge forms between the two beakers. By repeating a version of Pellat's experiment, it is shown that a horizontal bridge is stable by the action of electrohydrodynamic pressure. Thus, the static and dynamic properties of the phenomenon called a 'floating water bridge' can be explained by the gradient of Maxwell pressure, replenishing the liquid within the bridge against any drainage mechanism. It is also shown that a number of liquids can form stable and long horizontal bridges. The stability of such a connection, and the asymmetry in mass flow through such bridges caused by the formation of ion clouds in the vicinity of the electrodes, is also discussed by two further experiments. (orig.)

Characterization of a tricationic trigonal bipyramidal iron(IV) cyanide complex, with a very high reduction potential, and its iron(II) and iron(III) congeners.

Science.gov (United States)

England, Jason; Farquhar, Erik R; Guo, Yisong; Cranswick, Matthew A; Ray, Kallol; Münck, Eckard; Que, Lawrence

2011-04-04

Currently, there are only a handful of synthetic S = 2 oxoiron(IV) complexes. These serve as models for the high-spin (S = 2) oxoiron(IV) species that have been postulated, and confirmed in several cases, as key intermediates in the catalytic cycles of a variety of nonheme oxygen activating enzymes. The trigonal bipyramidal complex [Fe(IV)(O)(TMG(3)tren)](2+) (1) was both the first S = 2 oxoiron(IV) model complex to be generated in high yield and the first to be crystallographically characterized. In this study, we demonstrate that the TMG(3)tren ligand is also capable of supporting a tricationic cyanoiron(IV) unit, [Fe(IV)(CN)(TMG(3)tren)](3+) (4). This complex was generated by electrolytic oxidation of the high-spin (S = 2) iron(II) complex [Fe(II)(CN)(TMG(3)tren)](+) (2), via the S = 5/2 complex [Fe(III)(CN)(TMG(3)tren)](2+) (3), the progress of which was conveniently monitored by using UV-vis spectroscopy to follow the growth of bathochromically shifting ligand-to-metal charge transfer (LMCT) bands. A combination of X-ray absorption spectroscopy (XAS), Mössbauer and NMR spectroscopies was used to establish that 4 has a S = 0 iron(IV) center. Consistent with its diamagnetic iron(IV) ground state, extended X-ray absorption fine structure (EXAFS) analysis of 4 indicated a significant contraction of the iron-donor atom bond lengths, relative to those of the crystallographically characterized complexes 2 and 3. Notably, 4 has an Fe(IV/III) reduction potential of ∼1.4 V vs Fc(+/o), the highest value yet observed for a monoiron complex. The relatively high stability of 4 (t(1/2) in CD(3)CN solution containing 0.1 M KPF(6) at 25 °C ≈ 15 min), as reflected by its high-yield accumulation via slow bulk electrolysis and amenability to (13)C NMR at -40 °C, highlights the ability of the sterically protecting, highly basic peralkylguanidyl donors of the TMG(3)tren ligand to support highly charged high-valent complexes.

Lean Construction Applications for Bridge Inspection

Science.gov (United States)

2017-10-01

Lean philosophy was used to analyze the efficiency of bridge inspection. Emphasis was put on identifying activities that add value to the final output, an owner approved bridge inspection report. 26 bridge inspections were shadowed. Time spent on bri...

Spread prestressed concrete slab beam bridges.

Science.gov (United States)

2015-04-01

TxDOT uses prestressed slab beam bridges for short-span bridges ranging from approximately 3050 ft in : length. These bridges have precast, pretensioned slab beams placed immediately adjacent to one another : with a cast-in-place slab made composi...

Hydrodynamic forces on inundated bridge decks

Science.gov (United States)

2009-05-01

The hydrodynamic forces experienced by an inundated bridge deck have great importance in the design of bridges. Specifically, the drag force, lift force, and the moment acting on the bridge deck under various levels of inundation and a range of flow ...

Development of Inspection Robots for Bridge Cables

Directory of Open Access Journals (Sweden)

Hae-Bum Yun

2013-01-01

Full Text Available This paper presents the bridge cable inspection robot developed in Korea. Two types of the cable inspection robots were developed for cable-suspension bridges and cable-stayed bridge. The design of the robot system and performance of the NDT techniques associated with the cable inspection robot are discussed. A review on recent advances in emerging robot-based inspection technologies for bridge cables and current bridge cable inspection methods is also presented.

Design and construction of Chiburiko Bridge (stress ribbon bridge). Chiburiko bashi (tsurishoban kyo) no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Kamisakoda, K; Tokuyama, S; Sano, K; Onuma, K [Kashima Corp., Tokyo (Japan)

1992-07-30

Chiburiko Bridge lies across Chiburiko which is a lake for agricultural water, and is used by people, carts and cars for administration. It is a stressed-ribbon bridge with the road surface made with concrete covered bands of cables stretched between abutments, and is the first highway bridge in Japan. A report is made on the plan and construction of the bridge. Integration of the precast slab with the cast-in-place concrete as well as mutual integration of the precast slabs are validated by the use of a reproduced model of a part of the bridge. Floor slabs are suspended by cables, and can be constructed with no form nor support by integrating cast-in-place concrete with the precast slabs on mutually joined precast slabs. It has been said that the stressed-ribbon bridge has a structure suitable for long span bridges because it has a simple structure. Studies, however, seems to be necessary on the impact caused by running of vehicles and on the wind resisting stability. 3 refs., 17 figs., 2 tabs.

The South Carolina bridge-scour envelope curves

Science.gov (United States)

Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral W.

2016-09-30

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations to evaluate historical, riverine bridge scour in the Piedmont and Coastal Plain regions of South Carolina. These investigations included data collected at 231 riverine bridges, which lead to the development of bridge-scour envelope curves for clear-water and live-bed components of scour. The application and limitations of the South Carolina bridge-scour envelope curves were documented in four reports, each report addressing selected components of bridge scour. The current investigation (2016) synthesizes the findings of these previous reports into a guidance manual providing an integrated procedure for applying the envelope curves. Additionally, the investigation provides limited verification for selected bridge-scour envelope curves by comparing them to field data collected outside of South Carolina from previously published sources. Although the bridge-scour envelope curves have limitations, they are useful supplementary tools for assessing the potential for scour at riverine bridges in South Carolina.

Assessment of structural condition of Libeň Bridge

Directory of Open Access Journals (Sweden)

Kněž Petr

2017-01-01

Full Text Available The paper presents diagnostic and load tests of the Inundation bridge which is part of a group of bridges called The Libeň bridge group in Prague. The Libeň bridge group consists of two arched and several framed bridges spanning the Vltava river. One of the vaulted bridges consists of 5 arches and the other vaulted bridge (called Inundation bridge consists of only one arch. Arched bridges are extraordinary structures with both technical and historical value. Since the inundation bridge has the largest arch of whole group, it was selected for testing purposes. The bridge is assembled with three-hinged arch made of concrete. The hinges are made of reinforced concrete and lead contact slabs. Detailed measurements of geometry and material properties were made on the bridge. Based on these measurements a computer model was created to verify the behavior of the structure. Both static and dynamic calculations were performed. Measurements of dynamic characteristics were made during normal operation and with hydraulic vibration exciter. This article will focus on comparing the results of dynamic calculation of the modeled structure and properties measured on real structure excited by hydraulic vibration exciter.

Students design composite bridges

NARCIS (Netherlands)

Stark, J.W.B.; Galjaard, J.C.; Brekelmans, J.W.P.M.

1999-01-01

The paper gives an overview of recent research on steel-concrete composite bridge design by students of Delft University of Technology doing their master's thesis. Primary objective of this research was to find possibilities for application of steel-concrete composite bridges in the Netherlands,

33 CFR 118.140 - Painting bridge piers.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Painting bridge piers. 118.140 Section 118.140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.140 Painting bridge piers. The District Commander may require...

Superconductivity in small metal bridges

International Nuclear Information System (INIS)

Hannah, E.C.

1975-01-01

Josephson effects in weaklinks are discussed for low and high frequency regimes using simple perturbation techniques. It is proven that no measurement of the supercurrent dependence upon frequency above the Riedel peak frequency can be made using rf sources whose frequencies are below the Riedel peak. Thus the bulk of work done in the field on the high frequency structure of the Josephson current is shown to be invalid. Metal bridges shorter than a newly defined temperature independent length for superconductors, l/sub PHONON/, are proven to be identical in their Josephson current behavior to tunneling junctions. The BCS gap equation is generalized to include voltage gradient effects on pairs within the bridge. The oscillation frequency for long bridges (l/sub BRIDGE/ greater than l/sub PHONON/) is shown to be limited to less than 10'' Hz. An experimental test of the new voltage dependent gap is made as well as tests of the pair reforming time of bridges

Bridge scour monitoring technologies : development of evaluation and selection protocols for application on river bridges in Minnesota.

Science.gov (United States)

2010-03-01

Bridge failure or loss of structural integrity can result from scour of riverbed sediment near bridge abutments or : piers during high-flow events in rivers. In the past 20 years, several methods of monitoring bridge scour have been : developed spann...

33 CFR 118.90 - Bridges crossing channel obliquely.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridges crossing channel obliquely. 118.90 Section 118.90 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.90 Bridges crossing channel obliquely. Bridges...

33 CFR 118.100 - Retroreflective panels on bridge piers.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Retroreflective panels on bridge... SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.100 Retroreflective panels on bridge piers. The... 12 inches square. (c) To mark bridge piers or channel sides on bridges not required to have bridge...

Concrete-Filled Steel Tube Arch Bridges in China

Directory of Open Access Journals (Sweden)

Jielian Zheng

2018-02-01

Full Text Available In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube (CFST arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has been increasing rapidly, which is rare in the history of bridge development. The large-scale construction of expressways and high-speed railways demands the development of long-span arch bridges, and advances in design and construction techniques have made it possible to construct such bridges. In the present study, the current status, development, and major innovative technologies of CFST arch bridges and concrete arch bridges with a CFST skeleton in China are elaborated. This paper covers the key construction technologies of CFST arch bridges, such as the design, manufacture, and installation of steel tube arch trusses, the preparation and pouring of in-tube concrete, and the construction of the world’s longest CFST arch bridge—the First Hejiang Yangtze River Bridge. The main construction technologies of reinforced concrete arch bridges are also presented, which include cable-stayed fastening-hanging cantilever assembly, adjusting the load by means of stay cables, surrounding the concrete for arch rib pouring, and so forth. In addition, the construction of two CFST skeleton concrete arch bridges—the Guangxi Yongning Yong River Bridge and the Yunnan–Guangxi Railway Nanpan River Bridge—is discussed. CFST arch bridges in China have already gained a world-leading position; with the continuous innovation of key technologies, China will become the new leader in promoting the development of arch bridges. Keywords: Concrete-filled steel tube (CFST arch bridge, Steel-reinforced concrete arch bridge, Cable-stayed fastening-hanging cantilever assembly, Vacuum-assisted pouring in-tube concrete, Adjusting load by stay cables

Design and construction of Ogawa bridge; Ogawa bashi no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Hori, T.; Chigira, F. [Kajima Corp., Tokyo (Japan); Sakao, H.

1995-09-30

Ogawa bridge 230m long by 15.5m wide has been planned on the national road No.401 at Katashina-mura in Gunma Prefecture. Structure mode is two spans continuous PC cable-stayed obliquely system, and a main tower is H type (height: 56m from the road surface) and is located at the center of the bridge alone. This place corresponding to the entrance of Oze famous national park, the main tower is designed so as to have bulge, imaging Mizubasho (lysichiton camtschatcense), from the middle part of the pier to the lower part of the main tower. Arrangement of the cables is designed as two faces of hung fun type and one side face is composed of 13 steel strands (dia. 15.2mm wire x 27 (partly 19); covered with PE tube) in front and rear respectively. A main girder is the box type PC block 2.3m height by 4m or 3m long, and 3m long one is for fastening with a cable. Centering on the main tower, the girder blocks are successively connected in front and rare alternatively and are fastened with cables in part. This overhanging connection work is carried out by two special movable conveyers `Wagens`. 26 figs., 2 tabs.

Reliability Modeling of Double Beam Bridge Crane

Science.gov (United States)

Han, Zhu; Tong, Yifei; Luan, Jiahui; Xiangdong, Li

2018-05-01

This paper briefly described the structure of double beam bridge crane and the basic parameters of double beam bridge crane are defined. According to the structure and system division of double beam bridge crane, the reliability architecture of double beam bridge crane system is proposed, and the reliability mathematical model is constructed.

LIGHT BRIDGE IN A DEVELOPING ACTIVE REGION. I. OBSERVATION OF LIGHT BRIDGE AND ITS DYNAMIC ACTIVITY PHENOMENA

International Nuclear Information System (INIS)

Toriumi, Shin; Katsukawa, Yukio; Cheung, Mark C. M.

2015-01-01

Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce a wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the assembling process of nascent sunspots. The ultimate goal of this series of papers is to reveal the nature of light bridges in developing ARs and the occurrence of activity events associated with the light bridge structures from both observational and numerical approaches. In this first paper, exploiting the observational data obtained by Hinode, the Interface Region Imaging Spectrograph, and the Solar Dynamics Observatory, we investigate the detailed structure of the light bridge in NOAA AR 11974 and its dynamic activity phenomena. As a result, we find that the light bridge has a weak, horizontal magnetic field, which is transported from the interior by a large-scale convective upflow and is surrounded by strong, vertical fields of adjacent pores. In the chromosphere above the bridge, a transient brightening occurs repeatedly and intermittently, followed by a recurrent dark surge ejection into higher altitudes. Our analysis indicates that the brightening is the plasma heating due to magnetic reconnection at lower altitudes, while the dark surge is the cool, dense plasma ejected from the reconnection region. From the observational results, we conclude that the dynamic activity observed in a light bridge structure such as chromospheric brightenings and dark surge ejections are driven by magnetoconvective evolution within the light bridge and its interaction with the surrounding magnetic fields

LIGHT BRIDGE IN A DEVELOPING ACTIVE REGION. I. OBSERVATION OF LIGHT BRIDGE AND ITS DYNAMIC ACTIVITY PHENOMENA

Energy Technology Data Exchange (ETDEWEB)

Toriumi, Shin; Katsukawa, Yukio [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheung, Mark C. M., E-mail: shin.toriumi@nao.ac.jp [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Building/252, Palo Alto, CA 94304 (United States)

2015-10-01

Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce a wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the assembling process of nascent sunspots. The ultimate goal of this series of papers is to reveal the nature of light bridges in developing ARs and the occurrence of activity events associated with the light bridge structures from both observational and numerical approaches. In this first paper, exploiting the observational data obtained by Hinode, the Interface Region Imaging Spectrograph, and the Solar Dynamics Observatory, we investigate the detailed structure of the light bridge in NOAA AR 11974 and its dynamic activity phenomena. As a result, we find that the light bridge has a weak, horizontal magnetic field, which is transported from the interior by a large-scale convective upflow and is surrounded by strong, vertical fields of adjacent pores. In the chromosphere above the bridge, a transient brightening occurs repeatedly and intermittently, followed by a recurrent dark surge ejection into higher altitudes. Our analysis indicates that the brightening is the plasma heating due to magnetic reconnection at lower altitudes, while the dark surge is the cool, dense plasma ejected from the reconnection region. From the observational results, we conclude that the dynamic activity observed in a light bridge structure such as chromospheric brightenings and dark surge ejections are driven by magnetoconvective evolution within the light bridge and its interaction with the surrounding magnetic fields.

Bridge Aesthetics and Structural Honesty

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

In bridges the overall form must be chosen with due respect to the transmission of forces if efficient structures shall be created, The design must therefore be governed by experienced structural engineers - in some cases assisted by aesthetic advisers on specific issues. Some basic requirements...... decisive for choosing the form of trusses, arches and cable-stayed bridges are outlined, and several examples show bridges designed without giving priority to the structural aspects....

Strategies For The Replacement Of Historic Bridge Guardrails

OpenAIRE

Clauss, Adam J.

2014-01-01

Bridges that are designated historic present a special challenge to bridge engineers whenever rehabilitation work or improvements are made to the bridges. Federal and state laws protect historically significant bridges, and railings on these bridges can be subject to protection because of the role they play in aesthetics. Unfortunately, original railings on historic bridges do not typically meet current crash-test requirements and typically do not meet current standards for railing height and...

When, where and how the bridge breaks: anaphase bridge breakage plays a crucial role in gene amplification and HSR generation

International Nuclear Information System (INIS)

Shimizu, Noriaki; Shingaki, Kenta; Kaneko-Sasaguri, Yukiko; Hashizume, Toshihiko; Kanda, Teru

2005-01-01

Amplified genes are frequently localized on extrachromosomal double minutes (DMs) or in chromosomal homogenously staining regions (HSRs). We previously showed that a plasmid bearing a mammalian replication initiation region could efficiently generate DMs and HSRs after transfection into human tumor cell lines. The Breakage-Fusion-Bridge (BFB) cycle model, a classical model that explains how HSRs form, could also be used to explain how the transfected plasmids generate HSRs. The BFB cycle model involves anaphase bridge formation due to the presence of dicentric chromosomes, followed by the breakage of the bridge. In this study, we used our plasmid-based model system to analyze how anaphase bridges break during mitosis. Dual-color fluorescence in situ hybridization analyses revealed that anaphase bridges were most frequently severed in their middle irrespective of their lengths, which suggests that a structurally fragile site exists in the middle of the anaphase bridge. Breakage of the chromosomal bridges occurred prior to nuclear membrane reformation and the completion of cytokinesis, which indicates that mechanical tension rather than cytokinesis is primarily responsible for severing anaphase bridges. Time-lapse observation of living cells revealed that the bridges rapidly shrink after being severed. If HSR length was extended too far, the bridge could no longer be resolved and became tangled depending on the tension. The unbroken bridge appeared to inhibit the completion of cytokinesis. These observations strongly suggest that anaphase bridges are highly elastic and that the length of the spindle axis determines the maximal HSR length

33 CFR 118.70 - Lights on swing bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on swing bridges. 118.70 Section 118.70 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.70 Lights on swing bridges. (a) Swing span lights on through bridges. Each...

33 CFR 118.65 - Lights on fixed bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on fixed bridges. 118.65 Section 118.65 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.65 Lights on fixed bridges. (a) Each fixed bridge span over a navigable...

23 CFR 650.409 - Evaluation of bridge inventory.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Evaluation of bridge inventory. 650.409 Section 650.409... Evaluation of bridge inventory. (a) Sufficiency rating of bridges. Upon receipt and evaluation of the bridge inventory, a sufficiency rating will be assigned to each bridge by the Secretary in accordance with the...

Effects of Electrolyte on Floating Water Bridge

OpenAIRE

Hideo Nishiumi; Fumitaka Honda

2009-01-01

Fuchs found phenomena that when high voltage is applied to deionized water filled in two contacted beakers, a floating water bridge forms spontaneously. In this paper, we examined flow direction of water bridge and what effects the addition of electrolytes such as NaCl, NaOH, and N H 4 C l to the floating water bridge would give. We found that ionization degree reduced the length of water bridge though insoluble electrolyte A l 2 O 3 had no effect on the length of water bridge.

A data management infrastructure for bridge monitoring

Science.gov (United States)

Jeong, Seongwoon; Byun, Jaewook; Kim, Daeyoung; Sohn, Hoon; Bae, In Hwan; Law, Kincho H.

2015-04-01

This paper discusses a data management infrastructure framework for bridge monitoring applications. As sensor technologies mature and become economically affordable, their deployment for bridge monitoring will continue to grow. Data management becomes a critical issue not only for storing the sensor data but also for integrating with the bridge model to support other functions, such as management, maintenance and inspection. The focus of this study is on the effective data management of bridge information and sensor data, which is crucial to structural health monitoring and life cycle management of bridge structures. We review the state-of-the-art of bridge information modeling and sensor data management, and propose a data management framework for bridge monitoring based on NoSQL database technologies that have been shown useful in handling high volume, time-series data and to flexibly deal with unstructured data schema. Specifically, Apache Cassandra and Mongo DB are deployed for the prototype implementation of the framework. This paper describes the database design for an XML-based Bridge Information Modeling (BrIM) schema, and the representation of sensor data using Sensor Model Language (SensorML). The proposed prototype data management framework is validated using data collected from the Yeongjong Bridge in Incheon, Korea.

Railway bridge monitoring during construction and sliding

Science.gov (United States)

Inaudi, Daniele; Casanova, Nicoletta; Kronenberg, Pascal; Vurpillot, Samuel

1997-05-01

The Moesa railway bridge is a composite steel concrete bridge on three spans of 30 m each. The 50 cm thick concrete deck is supported on the lower flanges of two continuous, 2.7 m high I-beams. The bridge has been constructed alongside an old metallic bridge. After demolishing this one, the new bridge has been slid for 5 m by 4 hydraulic jacks and positioned on the refurbished piles of the old bridge. About 30 fiber optic, low-coherence sensors were imbedded in the concrete deck to monitor its deformations during concrete setting and shrinkage, as well as during the bridge sliding phase. In the days following concrete pour it was possible to follow its thermal expansion due to the exothermic setting reaction and the following thermal and during shrinkage. The deformations induced by the additional load produced by the successive concreting phases were also observed. During the bridge push, which extended over six hours, the embedded and surface mounted sensors allowed the monitoring of the curvature variations in the horizontal plane due to the slightly uneven progression of the jacks. Excessive curvature and the resulting cracking of concrete could be ruled out by these measurements. It was also possible to observe the bridge elongation under the heating action of the sun.

On the effect of nuclear bridge modes on donor-acceptor electronic coupling in donor-bridge-acceptor molecules

International Nuclear Information System (INIS)

Davis, Daly; Toroker, Maytal Caspary; Speiser, Shammai; Peskin, Uri

2009-01-01

We report a theoretical study of intra-molecular electronic coupling in a symmetric DBA (donor-bridge-acceptor) complex, in which a donor electronic site is coupled to an acceptor site by way of intervening orbitals of a molecular bridge unit. In the off-resonant (deep tunneling) regime of electronic transport, the lowest unoccupied molecular orbitals (MO's) of the DBA system are split into distinguishable donor/acceptor and bridge orbitals. The effect of geometrical changes at the bridge on the donor/acceptor electronic energy manifold is studied for local stretching and bending modes. It is demonstrated that the energy splitting in the manifold of donor/acceptor unoccupied MOs changes in response to such changes, as assumed in simple McConnell-type models. Limitations of the simple models are revealed where the electronic charging of the bridge orbitals correlates with increasing donor/acceptor orbital energy splitting only for stretching but not for bending bridge modes.

IceBridge Mission Flight Reports

Data.gov (United States)

National Aeronautics and Space Administration — The IceBridge Mission Flight Reports data set contains flight reports from NASA Operation IceBridge Greenland, Arctic, Antarctic, and Alaska missions. Flight reports...

Bridges analysis, design, structural health monitoring, and rehabilitation

CERN Document Server

Bakht, Baidar

2015-01-01

This book offers a valuable guide for practicing bridge engineers and graduate students in structural engineering; its main purpose is to present the latest concepts in bridge engineering in fairly easy-to-follow terms. The book provides details of easy-to-use computer programs for: ·      Analysing slab-on-girder bridges for live load distribution. ·      Analysing slab and other solid bridge components for live load distribution. ·      Analysing and designing concrete deck slab overhangs of girder bridges under vehicular loads. ·      Determining the failure loads of concrete deck slabs of girder bridges under concentrated wheel loads. In addition, the book includes extensive chapters dealing with the design of wood bridges and soil-steel bridges. Further, a unique chapter on structural health monitoring (SHM) will help bridge engineers determine the actual load carrying capacities of bridges, as opposed to their perceived analytical capacities. The chapter addressing structures...

Virtual Bridge Design Challenge

Science.gov (United States)

Mitts, Charles R.

2013-01-01

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

The floating water bridge

International Nuclear Information System (INIS)

Fuchs, Elmar C; Woisetschlaeger, Jakob; Gatterer, Karl; Maier, Eugen; Pecnik, Rene; Holler, Gert; Eisenkoelbl, Helmut

2007-01-01

When high voltage is applied to distilled water filled in two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed experimental analysis reveals static and dynamic structures as well as heat and mass transfer through this bridge

MODERN ASPECTS OF BRIDGES MONITORING

Directory of Open Access Journals (Sweden)

M. I. Kazakevych

2007-12-01

Full Text Available The major concepts of the elaboration and realization of the bridge construction monitoring systemic approach are presented in this paper. The main peculiarity of the bridge monitoring modern aspect is pointed out here, namely, the transition from the demands of providing the reliability to the demands of providing the whole complex of the structure consumer qualities. The criteria of diagnostics of the bridge exploitation reliability as the fundamental aim of monitoring are formulated here.

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

Science.gov (United States)

2010-10-07

... INFORMATION CONTACT: Ms. Ann Shemaka, Office of Bridge Technology, HIBT-30, (202) 366-1575, or Mr. Thomas Everett, Office of Bridge Technology, HIBT-30, (202) 366-4675, Federal Highway Administration, 1200 New... is categorized by the following material types, which are identified in the NBI: steel, concrete, pre...

77 FR 53251 - Annual Materials Report on New Bridge Construction and Bridge Rehabilitation

Science.gov (United States)

2012-08-31

... INFORMATION CONTACT: Ms. Ann Shemaka, Office of Bridge Technology, (202) 366-1575, or via email at [email protected] or Mr. Thomas Everett, Office of Bridge Technology, (202) 366-4675, or via email at thomas... the NBI: steel, concrete, pre-stressed concrete, and other. The category ``other'' includes wood...

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

Science.gov (United States)

2011-09-06

... INFORMATION CONTACT: Ms. Ann Shemaka, Office of Bridge Technology, HIBT-30, (202) 366-1575, or Mr. Thomas Everett, Office of Bridge Technology, HIBT-30, (202) 366-4675, Federal Highway Administration, 1200 New... is categorized by the following material types, which are identified in the NBI: steel, concrete, pre...

Prosthetic rehabilitation using adhesive bridge and fixed-fixed bridge on the maxilla and telescopic crown overdenture on mandible

Directory of Open Access Journals (Sweden)

Indah Sulistiawaty

2016-12-01

Full Text Available Prosthetic rehabilitation is the rehabilitation process of masticatory and esthetics function for patients missing teeth and alveolar bone by means of manufacture and installation of dentures. The prosthetic rehabilitation commonly used include denture adhesive bridge, fixed-fixed bridge, as well as telescopic overdenture. Adhesive bridge is bridge denture consisting of single pontic and two retainer wings attached to the abutment using cement or resin. Fixed-fixed bridge is a bridge denture with rigid connectors on both ends of the pontics, whereas the telescopic crown Overdenture is a removable denture that uses linked precision on the original tooth in the form of primary coping on abutment and secondary coping on the denture. To expose the procedures of prosthetic rehabilitation using adhesive bridge and fixed-fixed bridge on the maxilla and telescopic crown Overdenture on mandible. Male patients aged 32 years came with complaints of difficulty to chew food because he had lost some teeth behind. In the maxilla, teeth are lost in the region of 15 and 16 performed by making the fixed-fixed bridge with abutment teeth 14 and 17. Loss of teeth in the region of 26, performed the manufacture of adhesive bridge with a box preparation on the occlusal 25 and 27. In the mandible, tooth loss in the region of 36,37,46, and 47 performed manufacture of telescopic crown Overdenture with primer coping on the teeth 35.38, 45, and 48 and the secondary coping on a metal frame. Prosthetic rehabilitation especially in the case of loss of back teeth is very important because with the denture patients can chew properly and maintain the stomatognathic system.

Remediation: Higher Education's Bridge to Nowhere

Science.gov (United States)

Complete College America, 2012

2012-01-01

The intentions were noble. It was hoped that remediation programs would be an academic bridge from poor high school preparation to college readiness. Sadly, remediation has become instead higher education's "Bridge to Nowhere." This broken remedial bridge is travelled by some 1.7 million beginning students each year, most of whom will…

Effects of Electrolyte on Floating Water Bridge

Directory of Open Access Journals (Sweden)

Hideo Nishiumi

2009-01-01

spontaneously. In this paper, we examined flow direction of water bridge and what effects the addition of electrolytes such as NaCl, NaOH, and NH4Cl to the floating water bridge would give. We found that ionization degree reduced the length of water bridge though insoluble electrolyte Al2O3 had no effect on the length of water bridge.

LIGHT BRIDGE IN A DEVELOPING ACTIVE REGION. II. NUMERICAL SIMULATION OF FLUX EMERGENCE AND LIGHT BRIDGE FORMATION

International Nuclear Information System (INIS)

Toriumi, Shin; Katsukawa, Yukio; Cheung, Mark C. M.

2015-01-01

Light bridges, the bright structure dividing umbrae in sunspot regions, show various activity events. In Paper I, we reported on an analysis of multi-wavelength observations of a light bridge in a developing active region (AR) and concluded that the activity events are caused by magnetic reconnection driven by magnetconvective evolution. The aim of this second paper is to investigate the detailed magnetic and velocity structures and the formation mechanism of light bridges. For this purpose, we analyze numerical simulation data from a radiative magnetohydrodynamics model of an emerging AR. We find that a weakly magnetized plasma upflow in the near-surface layers of the convection zone is entrained between the emerging magnetic bundles that appear as pores at the solar surface. This convective upflow continuously transports horizontal fields to the surface layer and creates a light bridge structure. Due to the magnetic shear between the horizontal fields of the bridge and the vertical fields of the ambient pores, an elongated cusp-shaped current layer is formed above the bridge, which may be favorable for magnetic reconnection. The striking correspondence between the observational results of Paper I and the numerical results of this paper provides a consistent physical picture of light bridges. The dynamic activity phenomena occur as a natural result of the bridge formation and its convective nature, which has much in common with those of umbral dots and penumbral filaments

Optimum Maintenance Strategies for Highway Bridges

DEFF Research Database (Denmark)

Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.

As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum...... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....

Investigation of Aerodynamic Interference between Twin Deck Bridges

Energy Technology Data Exchange (ETDEWEB)

Sitek, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division. Transportation Research and Analysis Computing Center (TRACC); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division. Transportation Research and Analysis Computing Center (TRACC); Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division. Transportation Research and Analysis Computing Center (TRACC)

2016-05-01

Construction of a twin bridge can be a cost effective and minimally disruptive way to increase capacity when an existing bridge is not near the end of its service life. With ever growing vehicular traffic, when demand approaches the capacity of many existing roads and bridges. Remodeling a structure with an insufficient number of lanes can be a good solution in case of smaller and less busy bridges. Closing down or reducing traffic on crossings of greater importance for the construction period, however, can result in major delays and revenue loss for commerce and transportation as well as increasing the traffic load on alternate route bridges. Multiple-deck bridges may be the answer to this issue. A parallel deck can be built next to the existing one, without reducing the flow. Additionally, a new bridge can be designed as a twin or multi-deck structure. Several such structures have been built throughout the United States, among them: - The New NY Bridge Project - the Tappan Zee Hudson River Crossing, - SR-182 Columbia River Bridge, - The Thaddeus Kosciusko Bridge (I-87), - The Allegheny River Bridge, Pennsylvania, which carries I76, - Fred Hartman Bridge, TX, see Figure 1.2. With a growing number of double deck bridges, additional, more detailed, studies on the interaction of such bridge pairs in windy conditions appears appropriate. Aerodynamic interference effects should be examined to assure the aerodynamic stability of both bridges. There are many studies on aerodynamic response of single deck bridges, but the literature on double-deck structures is not extensive. The experimental results from wind tunnels are still limited in number, as a parametric study is required, they can be very time consuming. Literature review shows that some investigation of the effects of gap-width and angle of wind incidence has been done. Most of the CFD computational studies that have been done were limited to 2D simulations. Therefore, it is desirable to investigate twin decks

Review of Energy Harvesters Utilizing Bridge Vibrations

Directory of Open Access Journals (Sweden)

Farid Ullah Khan

2016-01-01

Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

Fatigue Testing of Dental Bridges on Selected Examples

Directory of Open Access Journals (Sweden)

Urban Dariusz

2017-03-01

Full Text Available The paper presents example tests of the functional quality of selected designs of dental bridges. These were: porcelain bridges on a metal base (cobalt based alloy, porcelain bridges on a zirconia base (zirconia ceramic – Zirkon Zahn, and full zirconia bridges (Zirkon Zahn. For the purpose of the study, durability of bridges in cyclic fatigue testing was adopted as a measure of their quality. The tests were carried out on a Zwick Roell Z010 universal testing machine. They consisted in cyclic loading and unloading of dental bridges mounted on gypsum models at a loading force of F= 400 [N] and a frequency of load of f= 1 [Hz]. Each bridge was subjected to a cycle of 7200 loads. The results show that there are no significant differences in the functional quality of the bridges.

Vehicle - Bridge interaction, comparison of two computing models

Science.gov (United States)

Melcer, Jozef; Kuchárová, Daniela

2017-07-01

The paper presents the calculation of the bridge response on the effect of moving vehicle moves along the bridge with various velocities. The multi-body plane computing model of vehicle is adopted. The bridge computing models are created in two variants. One computing model represents the bridge as the Bernoulli-Euler beam with continuously distributed mass and the second one represents the bridge as the lumped mass model with 1 degrees of freedom. The mid-span bridge dynamic deflections are calculated for both computing models. The results are mutually compared and quantitative evaluated.

A novel method of adrenaline concentration detection using fiber optical biosensor based on the catalysis of iron(II) phthalocyanine

Science.gov (United States)

Zhou, Xuan; Huang, Jun; Li, Mingtian; Wang, Bin

2008-12-01

As an effective alternative to the nature enzyme, metallophthalocyanine (MPc), having the advantages of easy accessibility, good stability and low cost, are used as catalyzer for the adrenaline (AD) oxidation. In this paper, the oxidation of AD by dioxygen using iron(II) phthalocyanine (FePc) as the catalyst was studied by electronic absorption spectra. The experimental results indicate that the oxidation product of AD catalyzed by FePc is adrenochrome with characteristic peaks at 298 nm and 267 nm. The catalytic activities of FePc are evaluated by the ratios of the absorbance at 298 nm of adrenochrome. The optimal concentration, pH and temperature for the oxidation of AD are 5.0×10-5 M, 8.0 and 55 oC, respectively. By using lock-in technology, the fiber optic adrenaline biosensor based on FePc catalysis and fluorescence quenching was fabricated and studied. A linear relationship between φ, the phase delay of the sensor head, and AD concentration was observed in the range of 2.0×10-6 to 9.0×10-6 M and 2.0×10-5 to 9.0×10-5 M. The standard deviation (SD) values are 4.7×10-8 (n = 5) and 5.9×10-7 (n = 5) M, respectively, while the detection limit is 4.0×10-7 M. The biosensor has the response time of about 15 min and the preferred reproducibility and stability.

Seismic Passive Control of Cable-Stayed Bridges

Directory of Open Access Journals (Sweden)

Hosam-Eddin M. Ali

1995-01-01

Full Text Available A three-dimensional modeling procedure is proposed for cable-stayed bridges with rubber, steel, and lead energy dissipation devices. The passive control technique is investigated by considering the response of bridge models with and without energy dissipation devices. The impact of various design parameters on the seismic response of current and future bridge designs is studied. Appropriate locations and properties of the passive devices can achieve better performance for cable-stayed bridges by balancing the significant reduction in earthquake-induced forces against tolerable displacements. Proper design of passive systems can help provide solutions for retro-fitting some existing bridges.

Istanbul Bridge Conference 2014

CERN Document Server

Gülkan, Polat; Mahmoud, Khaled

2016-01-01

  The book includes peer-reviewed contributions selected from presentations given at the Istanbul Bridge Conference 2014, held from August 11 – 13 in Istanbul, Turkey. It reports on the current challenges in bridge engineering faced by professionals around the globe, giving a special emphasis to recently developed techniques, innovations and opportunities. The book covers key topics in the field, including modeling and analysis methods; construction and erection techniques; design for extreme events and condition assessment and structural health monitoring. There is a balanced presentation of theory, research and practice. This book, which provides the readers with a comprehensive and timely reference guide on current practices in bridge engineering, is intended for professionals, academic researchers and students alike.

INTERACTION OF IRON(II MIXED-LIGAND COMPLEXES WITH DNA: BASE-PAIR SPECIFICITY AND THERMAL DENATURATION STUDIES

Directory of Open Access Journals (Sweden)

Mudasir Mudasir

2010-06-01

Full Text Available A research about base-pair specificity of the DNA binding of [Fe(phen3]2+, [Fe(phen2(dip]2+ and [Fe(phen(dip2]2+ complexes and the effect of calf-thymus DNA (ct-DNA binding of these metal complexes on thermal denaturation of ct-DNA has been carried out. This research is intended to evaluate the preferential binding of the complexes to the sequence of DNA (A-T or G-C sequence and to investigate the binding strength and mode upon their interaction with DNA. Base-pair specificity of the DNA binding of the complexes was determined by comparing the equilibrium binding constant (Kb of each complex to polysynthetic DNA that contain only A-T or G-C sequence. The Kb value of the interaction was determined by spectrophotometric titration and thermal denaturation temperature (Tm was determined by monitoring the absorbance of the mixture solution of each complex and ct-DNA at λ =260 nm as temperature was elevated in the range of 25 - 100 oC. Results of the study show that in general all iron(II complexes studied exhibit a base-pair specificity in their DNA binding to prefer the relatively facile A-T sequence as compared to the G-C one. The thermal denaturation experiments have demonstrated that Fe(phen3]2+ and [Fe(phen2(dip]2+ interact weakly with double helical DNA via electrostatic interaction as indicated by insignificant changes in melting temperature, whereas [Fe(phen2(dip]2+  most probably binds to DNA in mixed modes of interaction, i.e.: intercalation and electrostatic interaction. This conclusion is based on the fact that the binding of [Fe(phen2(dip]2+ to ct-DNA moderately increase the Tm value of ct- DNA   Keywords: DNA Binding, mixed-ligand complexes

A Polish approach to FRP bridges

Science.gov (United States)

Siwowski, Tomasz; Rajchel, Mateusz

2017-12-01

The paper presents initial results of a new approach to FRP composite bridge construction that is presently being developed and tested in Poland. The concept combines lightweight concrete with FRP composites to create a durable highly optimised structure. The paper describes the bridge system itself and presents the research results on its development. The basic design is presented together with research results on its development: FEM analysis and a range of static test results of full-scale bridge beam experiments. The paper finishes with some test results of a full scale bridge that was constructed near Rzeszow in December 2015.

Virginia Bridge Information Systems Laboratory.

Science.gov (United States)

2014-06-01

This report presents the results of applied data mining of legacy bridge databases, focusing on the Pontis and : National Bridge Inventory databases maintained by the Virginia Department of Transportation (VDOT). Data : analysis was performed using a...

Reliability Assessment of Concrete Bridges

DEFF Research Database (Denmark)

Thoft-Christensen, Palle; Middleton, C. R.

This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

Complex Testing of the Bridges

Directory of Open Access Journals (Sweden)

Savić Adrijana

2016-01-01

Full Text Available This article describes the process of examining bridges. AB road bridge, founded on the columns by the Karpoš system and damaged due to erosive action of the river, is given as an example. The first tests of the bridge are conducted on the impact load of V 300, because of the appearance of longitudinal cracks. The results of the columns testing are presented in this paper, as well as the rehabilitation measures thus increasing the load capacity of the column.

Final Environmental Assessment, Horse Creek Bridge Replacement

Science.gov (United States)

2010-10-01

existing bridge pipes that have failed and replace the failed structure with a new, prefabricated pedestrian bridge within the original bridge footprint...vehicles, nor designed for support of standard passenger vehicle loads. The bridge would be a single prefabricated unit consisting of a steel grate...placed on new concrete abutments built on the existing foundations on the creek banks, and put in place by a crane operating from the vehicle parking

Stabilizer for seismically exposed bridge cranes

International Nuclear Information System (INIS)

Engelke, M.; Kuhr, H.

1982-01-01

The invention concerns a stabilizer for seismically exposed bridge cranes in reactor buildings. The trolley and the crane bridge are fitted with the stabilizer consisting of a bipartite safety catch which is connected with a joint and able to take up the vertical loads during an earthquake. This stabilizer is suitable for all kinds of bridge cranes operated in seismically active regions

SURGERY OF SYMPTOMATIC MYOCARDIAL BRIDGING

Directory of Open Access Journals (Sweden)

N. Maghamipour N. Safaei

2007-06-01

Full Text Available Myocardial bridging with systolic compression of the left anterior descending coronary artery (LAD may be associated with myocardial ischemia. In symptomatic myocardial bridging unresponsive to medical treatment, surgical unroofing of the left LAD can be performed. Little information is available about the long-term prognosis of patients with this coronary anomaly after the surgical unroofing, so we decided to evaluate the result of this operation. A total of 26 patients underwent surgical unroofing of myocardial bridging. Patients had a myocardial bridge of at least 3 cm in length in the middle of LAD and with more than 70% compression during systole. Unroofing was performed with cardiopulmonary bypass in 16 and with off pump technique in 10 patients. In 6 patients repeat angiographies for control of myotomy were done. In one of them a nonsignificant 20% narrowing was seen. Postoperative scintigraphic and angiographic studies demonstrated restoration of coronary flow and myocardial perfusion without residual myocardial bridges under beta-stimulation in 24 patients. Two patients had residual narrowing. With off pump technique, 1 patient had perforation of the right ventricle and 1 patient underwent reoperation because of incomplete unroofing during the first operation. None of the patients with cardiopulmonary bypass technique had residual chest pain or other complications. Surgical unroofing of myocardial bridging with the aid of cardiopulmonary bypass is a safe and easy procedure with low operative risk and with excellent functional results.

Modal analysis of cable-stayed UHPC bridge

Directory of Open Access Journals (Sweden)

Tej Petr

2017-01-01

Full Text Available This paper deals with the dynamic analysis of cable-stayed UHPC bridge over the Vltava river near town Melnik in Czech Republic, Europe. Bridge serves for pedestrians and cyclists. This work aims to familiarize the reader with dynamic calculations carried out and the results obtained, describing the dynamic properties of proposed bridge. The construction of bridge is designed as a cable-stayed structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tonnes. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings.

Microwave Josephson generation in thin film superconducting bridges

International Nuclear Information System (INIS)

Gubankov, V.N.; Koshelets, V.P.; Ovsyannikov, G.A.

1975-01-01

Thin-film bridges have some advantage over other types of superconducting weak links: good definition of electromagnetic parameters and of weak region geometry. Up to now Josephson properties of bridges have been investigated by using indirect methods (the effect of magnetic field on the critical current I 0 , the bridge behavior in a microwave field, etc.). Direct experimental observation of Josephson radiation from autonomous thin film bridges is reported. Microwave radiation in tin bridges of 'variable' thickness has been investigated where the thickness of the film forming the bridge is far less than the thickness of the bank films. (Auth.)

Floating liquid bridge charge dynamics

Science.gov (United States)

Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

2016-01-01

The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

Field performance of timber bridges. 11, Spearfish Creek stress-laminated box-beam bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter; K. Stanfill-McMillan

The Spearfish Creek bridge was constructed in 1992 in Spearfish, South Dakota. It is a single-span, stress-laminated, box-beam superstructure. Performance of the bridge is being monitored for 5 years, beginning at installation. This report summarizes results for the first 3-1/2 years of monitoring and includes information on the design, construction, and field...

Estimating bridge stiffness using a forced-vibration technique for timber bridge health monitoring

Science.gov (United States)

James P. Wacker; Xiping Wang; Brian Brashaw; Robert J. Ross

2006-01-01

This paper describes an effort to refine a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the frequency response of several simple-span, sawn timber beam (with plank deck) bridges located in St. Louis County, Minnesota. Static load deflections were also measured to...

Design aids of NU I-girders bridges.

Science.gov (United States)

2010-05-01

Precast prestressed concrete I-Girder bridges have become the most dominant bridge system in the United States. In the early design : stages, preliminary design becomes a vital first step in designing an economical bridge. Within the state of Nebrask...

Faster bridge construction using precast substructures : brief.

Science.gov (United States)

2011-07-01

Bridge replacement often requires road closures and detours that frustrate road users. It remains a key goal of Wisconsin DOT to reduce construction-related road use interruptions. This will be a challenge with bridges: Bridge inspections in 2007 ide...

BUILDING "BRIDGES" WITH QUALITY ASSURANCE

Science.gov (United States)

The papr describes how, rather than building "bridges" across centuries, quality assurance (QA) personnel have the opportunity to build bridges across technical disciplines, between public and private organizations, and between different QA groups. As reviewers and auditors of a...

Independence through social networks: bridging potential among older women and men.

Science.gov (United States)

Cornwell, Benjamin

2011-11-01

Most studies of older adults' social networks focus on their access to dense networks that yield access to social support. This paper documents gender differences in the extent to which older adults maintain a related, but distinct, form of social capital-bridging potential, which involves serving as a tie between two unconnected parties and thus boosts independence and control of everyday social life. I use egocentric social network data from a national sample of 3,005 older adults--collected in 2005-2006 by the National Social Life, Health, and Aging Project--to compare older men's and women's network bridging potential using multivariate regression analysis. Older women are more likely than older men to have bridging potential in their networks-between both kin and non-kin contacts. These gender differences increase with age. Older women are also more likely to have network members who are not connected to or monopolized by their spouse or partner. Some, but not all, of these gender differences are due to the fact that older women have larger social networks and maintain more ties to people outside of the household. These findings raise important questions about the relational advantages older women have over older men, including greater autonomy, and contradict stereotypes about women having more closely knit, kin-centered networks than men.

Inspection Based Evaluation of a Danish Road Bridge

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper it is shown how an inspection-based evaluation of a Danish road bridge may be performed using the BRIDGE1 and BRIDGE2 bridge management systems produced within the EC-supported research programme "Assessment of Performance and Optimal Strategies for Inspection and Maintenance...

Violin Bridge Mobility Analysis under In-Plane Excitation

Directory of Open Access Journals (Sweden)

Cheng-Zhong Zhang

2013-11-01

Full Text Available The vibration of a violin bridge is a dynamic contact vibration with two interfaces: strings-bridge, and bridge feet-top plate. In this paper, the mobility of an isolated bridge under in-plane excitation is explored using finite element modeling based on the contact vibration model. Numerical results show that the dynamic contact stiffness in the two contact interfaces has a great impact on the bridge mobility. A main resonance peak is observed in the frequency range of 2–3 kHz in the frequency response of the isolated bridge when the contact stiffness is smaller than a critical threshold. The main resonance peak frequency is affected by the contact stiffness as well. In order to verify the numerical findings, a novel experimental system is then designed on the basis of a piezoelectric dynamometer for bridge mobility analysis. Experimental results confirm the impact of the dynamic contact stiffness on the bridge mobility.

Violin bridge mobility analysis under in-plane excitation.

Science.gov (United States)

Zhang, Cheng-Zhong; Zhang, Guang-Ming; Ye, Bang-Yan; Liang, Li-Dong

2013-11-08

The vibration of a violin bridge is a dynamic contact vibration with two interfaces: strings-bridge, and bridge feet-top plate. In this paper, the mobility of an isolated bridge under in-plane excitation is explored using finite element modeling based on the contact vibration model. Numerical results show that the dynamic contact stiffness in the two contact interfaces has a great impact on the bridge mobility. A main resonance peak is observed in the frequency range of 2-3 kHz in the frequency response of the isolated bridge when the contact stiffness is smaller than a critical threshold. The main resonance peak frequency is affected by the contact stiffness as well. In order to verify the numerical findings, a novel experimental system is then designed on the basis of a piezoelectric dynamometer for bridge mobility analysis. Experimental results confirm the impact of the dynamic contact stiffness on the bridge mobility.

Monitoring bridge scour using fiber optic sensors.

Science.gov (United States)

2015-04-01

The scouring process excavates and carries away materials from the bed and banks of streams, and from : around the piers and abutments of bridges. Scour undermines bridges and may cause bridge failures due to : structural instability. In the last 30 ...

Covered Bridge Security Manual

Science.gov (United States)

Brett Phares; Terry Wipf; Ryan Sievers; Travis Hosteng

2013-01-01

The design, construction, and use of covered timber bridges is all but a lost art in these days of pre-stressed concrete, high-performance steel, and the significant growth both in the volume and size of vehicles. Furthermore, many of the existing covered timber bridges are preserved only because of their status on the National Registry of Historic Places or the...

Public response to bridge colors.

Science.gov (United States)

1973-01-01

To determine people's reactions to bridges painted in colors as white, yellow, green, blue, red, brown, black, and aluminum, two test bridges were selected in Charlottesville, Virginia. One was painted a different color each month and the other was k...

Dynamic behaviour of prestressed concrete bridges

International Nuclear Information System (INIS)

Javor, T.

1982-01-01

The paper presents the results of experimental research of dynamic effects on prestressed concrete bridges in dynamic load tests using testing vehicles. The bridges were passed over in both directions at various speeds also running over an artificial unevenness to produce impact loads. From investigated bridges are shown the dynamic quantities such as dynamic coefficients, natural frequency, logarithmical decrement of damping, etc. (orig.) [de

Salt bridge as a gatekeeper against partial unfolding.

Science.gov (United States)

Hinzman, Mark W; Essex, Morgan E; Park, Chiwook

2016-05-01

Salt bridges are frequently observed in protein structures. Because the energetic contribution of salt bridges is strongly dependent on the environmental context, salt bridges are believed to contribute to the structural specificity rather than the stability. To test the role of salt bridges in enhancing structural specificity, we investigated the contribution of a salt bridge to the energetics of native-state partial unfolding in a cysteine-free version of Escherichia coli ribonuclease H (RNase H*). Thermolysin cleaves a protruding loop of RNase H(*) through transient partial unfolding under native conditions. Lys86 and Asp108 in RNase H(*) form a partially buried salt bridge that tethers the protruding loop. Investigation of the global stability of K86Q/D108N RNase H(*) showed that the salt bridge does not significantly contribute to the global stability. However, K86Q/D108N RNase H(*) is greatly more susceptible to proteolysis by thermolysin than wild-type RNase H(*) is. The free energy for partial unfolding determined by native-state proteolysis indicates that the salt bridge significantly increases the energy for partial unfolding by destabilizing the partially unfolded form. Double mutant cycles with single and double mutations of the salt bridge suggest that the partially unfolded form is destabilized due to a significant decrease in the interaction energy between Lys86 and Asp108 upon partial unfolding. This study demonstrates that, even in the case that a salt bridge does not contribute to the global stability, the salt bridge may function as a gatekeeper against partial unfolding that disturbs the optimal geometry of the salt bridge. © 2016 The Protein Society.

Deflection control system for prestressed concrete bridges by CCD camera. CCD camera ni yoru prestressed concrete kyo no tawami kanri system

Energy Technology Data Exchange (ETDEWEB)

Noda, Y.; Nakayama, Y.; Arai, T. (Kawada Construction Co. Ltd., Tokyo (Japan))

1994-03-15

For the long-span prestressed concrete bridge (continuous box girder and cable stayed bridge), the design and construction control becomes increasingly complicated as construction proceeds because of its cyclic works. This paper describes the method and operation of an automatic levelling module using CCD camera and the experimental results by this system. For this automatic levelling system, the altitude can be automatically measured by measuring the center location of gravity of the target on the bridge surface using CCD camera. The present deflection control system developed compares the measured value by the automatic levelling system with the design value obtained by the design calculation system, and manages them. From the real-time continuous measurement for the long term, in which the CCD camera was set on the bridge surface, it was found that the stable measurement accuracy can be obtained. Successful application of this system demonstrates that the system is an effective and efficient construction aid. 11 refs., 19 figs., 1 tab.

IceBridge: Bringing a Field Campaign Home

Science.gov (United States)

Woods, J.; Beck, J.; Bartholow, S.

2015-12-01

IceBridge, a six-year NASA mission, is the largest airborne survey of Earth's polar ice ever flown. It will yield an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice. These flights will provide a yearly, multi-instrument look at the behavior of the rapidly changing features of the Greenland and Antarctic ice. Data collected during IceBridge will help scientists bridge the gap in polar observations between NASA's Ice, Cloud and Land Elevation Satellite (ICESat) -- in orbit since 2003 -- and ICESat-2, planned for 2017. ICESat stopped collecting science data in 2009, making IceBridge critical for ensuring a continuous series of observations. IceBridge will use airborne instruments to map Arctic and Antarctic areas once a year at a minimum, with new campaigns being developed during the Arctic melt season. IceBridge flights are conducted in the spring and summer for the Arctic and in the fall over Antarctica. Other smaller airborne surveys around the world are also part of the IceBridge campaign. IceBridge actively engages the public and educators through a variety of outlets ranging from communications strategies through social media outlets, to larger organized efforts such as PolarTREC. In field activities include blog posts, photo updates, in flight chat sessions, and more intensive live events to include google hangouts, where field team members can interact with the public during a scheduled broadcast. The IceBridge team provides scientists and other team members with the training and support to become communicators in their own right. There is an exciting new initiative where IceBridge will be collaborating with Undergraduate and Graduate students to integrate the next generation of scientists and communicators into the Science Teams. This will be explored through partnerships with institutions that are interested in mentoring through project based initiatives.

Bridge Deterioration Prediction Model Based On Hybrid Markov-System Dynamic

Directory of Open Access Journals (Sweden)

Widodo Soetjipto Jojok

2017-01-01

Full Text Available Instantaneous bridge failure tends to increase in Indonesia. To mitigate this condition, Indonesia’s Bridge Management System (I-BMS has been applied to continuously monitor the condition of bridges. However, I-BMS only implements visual inspection for maintenance priority of the bridge structure component instead of bridge structure system. This paper proposes a new bridge failure prediction model based on hybrid Markov-System Dynamic (MSD. System dynamic is used to represent the correlation among bridge structure components while Markov chain is used to calculate temporal probability of the bridge failure. Around 235 data of bridges in Indonesia were collected from Directorate of Bridge the Ministry of Public Works and Housing for calculating transition probability of the model. To validate the model, a medium span concrete bridge was used as a case study. The result shows that the proposed model can accurately predict the bridge condition. Besides predicting the probability of the bridge failure, this model can also be used as an early warning system for bridge monitoring activity.

Quantum Bidding in Bridge

Science.gov (United States)

Muhammad, Sadiq; Tavakoli, Armin; Kurant, Maciej; Pawłowski, Marcin; Żukowski, Marek; Bourennane, Mohamed

2014-04-01

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

Re-Assessment of Concrete Bridges

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper two aspects of re-assessment of the reliability of concrete bridges are discussed namely modelling of the corrosion of reinforcement and updating of uncertain variables. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling...

Rapid replacement/construction of bridges.

Science.gov (United States)

2012-11-01

Bridges are a key element of the transportation system because they control system capacity and are normally built at : the highest cost to the system. Once a bridge reaches its useful design service life, it needs to be replaced or : reconstructed i...

Static behaviors of long-span cable-stayed bridge; Chodai shachokyo no seiteki kyodo ni kansuru kosatsu

Energy Technology Data Exchange (ETDEWEB)

Xie, Xu [Saitama Univ., Saitama (Japan). Graduate School; Yamaguchi, H.; Ito, M. [Saitama Univ., Urawa (Japan). Faculty of Engineering

1996-04-21

In this study, incremental equation of cable-stayed bridge is formulated by finite element method taking the geometrical nonlinear analysis into account. Then, as an example of designing a bridge with 1500m span, setting up the initial tension, analysis of in-plane behavior caused by live loads as well as analysis of the behavior against wind caused by out-of-plane wind load that are necessary for designing a bridge with 1500m span are carried out. The main results obtained through the study are as follows. As for the cable stayed bridge with 1500m center super long-span having supplementary supporting points between the side arms, the geometrical non-linearity caused by the in-plane design live loads is not remarkable. The effects of wind which acts on girders on analysis of the behaviors against wind are different depending on the aerodynamic performance of the girder and in the case of high wind speed, strong effects on the behavior against wind of the in-plane and screws generate. As the changing of tension of the cable makes influences on the force of in-plane cross section and on displacement of the girder, if the wind speed is very high, the analysis results of the behaviors against wind of in-plane and screws of the cable-stayed bridge may be different depending on in what manner the wind load on the cable to be treated. 16 refs., 16 figs., 1 tab.

D0 Silicon Upgrade: Calorimeter Installation Bridge Non-Destructive Test Result

International Nuclear Information System (INIS)

Stredde, H.J.

1990-01-01

After the central calorimeter was installed on the center beam a cracked weld was found on the bridge. The weld was a partial penetration between the top rail plate and the T-1 steel nose section. The crack is fully across the width of the rail plate and the rail is depressed in a concave shape. That is, the depression is deeper in the center and feathers out to zero at the end of the rail. Upon close inspection it was obvious that there was no penetration of weld metal into the T-1 material. The assumption is that the T-1 was not properly pre-heated before welding. The reason for the concave depression comes from the fact that the rail plate rests on the flanges of the 'S' beams and that during welding the plate pulled off the beams. This weld failure can not propagate to any other welds and therefore, will not start a chain of failures. Clearly the failure of this weld did not hinder the installation of the central calorimeters. This weld failure occurred on both sides of the bridge. This failure did, however, alert us to check the critical weld on the bridge, S-beam webs to T-1 nose section, to assure us we had a sound weldment. (Note: it must be used again for both EC's). We contacted M.Q.S. Inspection Inc. (Lab contractor for N.D.T.). A technician from M.Q.S. came to DAB and performed an ultrasonic examination of the welds in question. The exam showed that we don't have a full penetration weld of the S Beam web, but that it is between 67-83%. A calculation was performed based on 67% penetration and the CC and EC loads. In both cases the weld stresses were well within acceptable limits (see calculations attached). Based on this result, it is not deemed necessary to modify the current weldment.

33 CFR 118.80 - Lights on bascule bridges.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lights on bascule bridges. 118.80 Section 118.80 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.80 Lights on bascule bridges. (a) Lift span lights. Each lift span of...

Precast Pearl-Chain concrete arch bridges

DEFF Research Database (Denmark)

Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

2015-01-01

A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... of a desired width. On top of the arch is a filling material to level out the surface of the above road. The filling only transfers vertical loads to the arch. The geometry and material properties of Super-Light Decks are presented, and we refer to several fullscale tests of Pearl-Chain arches where...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post...

Determination of in-situ strength on selected bridge element concrete girder and slab of Nagtahan bridge using rebound hammer test

International Nuclear Information System (INIS)

Uy, Bernadette Betsy B.; Banaga, Renato T.

2013-01-01

This study examined the extent of the damage due to fire on the affected areas of the bridge structure. The need to assess the damage of the Nagtahan Bridge is very useful to provide appropriate measures in the repair or in the reinforcement of the bridge, hence will ensure its strength and integrity. The study included two (2) spans of the bridge deck/slab with specific locations of the bridge that were subjected for testing. The Rebound Hammer was used as a preliminary test in evaluating the bridge condition. Its capability is to assess the in-place uniformity of concrete, to delineate regions in a structure of poor quality or deteriorated concrete, and to estimate the in-place strength; and ultimately, for relative comparison between the different structures of the bridge. With the use of the NDT Rebound Hammer Test, the researchers were able to determine whether or not the in-situ strength of the bridge's concrete has been weakened due to fire. The DPW-Standard Specification is the government acceptable manual, containing the acceptance criteria, used as the basis for standard construction procedures in the department.(author)

Spectrophotometric Determination of Iron(II and Cobalt(II by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone

Directory of Open Access Journals (Sweden)

V. S. Anusuya Devi

2012-01-01

Full Text Available Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH reacts with iron(II and cobalt(II to form reddish-brown and yellow-coloured [Fe(II-HNAHBH] and [Co(II-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II-HNAHBH], Beer’s law is obeyed over the concentration range of 0.055–1.373 μg mL−1 with a detection limit of 0.095 μg mL−1 and molar absorptivity ɛ, 5.6 × 104 L mol−1 cm−1. [Co(II-HNAHBH] complex obeys Beer’s law in 0.118–3.534 μg mL−1 range with a detection limit of 0.04 μg mL−1 and molar absorptivity, ɛ of 2.3 × 104 L mol−1 cm−1. Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content.

Future Trends in Reliability-Based Bridge Management

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

Future bridge management systems will be based on simple stochastic models predicting the residual strength of structural elements. The current deterministic management systems are not effective in optimizing e.g. the life cycle cost of a bridge or a system of bridges. A number of important factors...

Finite element analysis and frequency shift studies for the bridge coupler of the coupled cavity linear accelerator of the spallation neutron source.

Energy Technology Data Exchange (ETDEWEB)

Chen, Z. (Zukun)

2001-01-01

The Spallation Neutron Source (SNS) is an accelerator-based neutron scattering research facility. The linear accelerator (linac) is the principal accelerating structure and divided into a room-temperature linac and a superconducting linac. The normal conducting linac system that consists of a Drift Tube Linac (DTL) and a Coupled Cavity Linac (CCL) is to be built by Los Alamos National Laboratory. The CCL structure is 55.36-meters long. It accelerates H- beam from 86.8 Mev to 185.6 Mev at operating frequency of 805 MHz. This side coupled cavity structure has 8 cells per segment, 12 segments and 11 bridge couplers per module, and 4 modules total. A 5-MW klystron powers each module. The number 3 and number 9 bridge coupler of each module are connected to the 5-MW RF power supply. The bridge coupler with length of 2.5 {beta}{gamma} is a three-cell structure and located between the segments and allows power flow through the module. The center cell of each bridge coupler is excited during normal operation. To obtain a uniform electromagnetic filed and meet the resonant frequency shift, the RF induced heat must be removed. Thus, the thermal deformation and frequency shift studies are performed via numerical simulations in order to have an appropriate cooling design and predict the frequency shift under operation. The center cell of the bridge coupler also contains a large 4-inch slug tuner and a tuning post that used to provide bulk frequency adjustment and field intensity adjustment, so that produce the proper total field distribution in the module assembly.

Assessment of Replacement Bridge using Proof Load Test

Science.gov (United States)

Sundru, Saibabu

2017-11-01

This work begins with an overview of the condition assessment of old bridge and explained reasons for demolishing of the bridge. Briefly presented flexural analysis of two stage post-tensioned prestressed concrete girder, which will be replace the old (new bridge). Construction of I-girder and composite girder at first stage and second stage prestressing respectively is explained with figures. Assessment of the load-caring capacity of the one span of the replacement bridge with simple supports using proof load test is presented which is mandatory according to Indian standards. Weighted sand bags were used to load the bridge up to a predetermined service load with impact factor. Deflections of the I-girders of the bridge were measured at selected locations along and across the bridge span and compared with computed values. Linear response was observed during loading and unloading. Considering the load test results, theoretical estimation and criteria as stipulated in codes of practice, it can be inferred that prestressed concrete I-girder bridge span has adequate capacity to carry the loads and hence, deemed to have passed the test.

Planning of Tatara Bridge. Chodai shachokyo-Tataraohashi-no keikaku gaiyo

Energy Technology Data Exchange (ETDEWEB)

Okukawa, A. (Honshu-Shikoku Bridge Authority, Tokyo (Japan))

1991-12-05

The outline of the Tatara Bridge is given to introduce the features of the entire structural system and fundamental problems concerning the construction of the huge cable stayed bridge. The central span of the bridge is 890m. The topography and geological features of the bridging point are reviewed, and social conditions such as being in a national park, safety for sailing, etc. are taken into consideration for various technological studies on the construction of the huge bridge. Bridge piers are provided in the side spans and appropriate counter weight is loaded to design a more economical bridge which is more suitable for the topography as compared with a suspension bridge. The cable stayed bridge requires no anchorage which is necessary for a suspension bridge with very little topological alteration, and an excellent result is obtained both in cost and term of construction as compared with a suspension bridge. The rigidity of the cable stayed bridge is high, and the stability of the resistance to wind of the structure is also very satisfactory. As a result, it is concluded that the bridge can be designed and constructed using currently available technologies, and a cable stayed bridge is selected in August, 1990 as the type for the Tatara Bridge. 9 figs., 1 tab.

Radioembolization using yttrium-90 microspheres as bridging and downstaging treatment for unresectable hepatocellular carcinoma before liver transplantation: initial single-center experience.

Science.gov (United States)

Abdelfattah, M R; Al-Sebayel, M; Broering, D; Alsuhaibani, H

2015-03-01

HCC is the sixth most common malignancy worldwide and is the third most common cause of cancer related mortality. Moreover, the incidence of HCC is increasing. Surgical treatments for HCC including resection and/or transplantation provide the best curative outcomes in early stages. Unfortunately, many patients present at an advanced stage. Currently, locoregional therapies have an emerging role in the management of HCC for bridging to liver transplantation and for downstaging the disease to within transplant criteria. Radioembolization is among commonly used locoregional therapies. To describe our initial experience with the use of Therasphere® as bridging or downstaging modality before liver transplantation, including our institutional indications, technique and outcome. We retrospectively examined our database for liver transplantation after the use of Therasphere®. Nine patients were identified and reported. They were 5 females and 4 males. Their current age range is 40-72 years with a mean of 53.8 ± 9.5 years. Three patients had Therasphere® as downstaging treatment to our institutional transplantation criteria. Our institution is using UCSF criteria as a cut off limit for liver transplantation as primary treatment modality. The other 6 patients had Therasphere® as bridging for liver transplantation especially when other modalities are not possible. None of these lesions were treated by any other locoregional treatment before or after Therasphere®. Follow-up after liver transplantation ranged between 3.7 and 60.1 months (mean of 15.8 ± 17.7 months). All patients are still living, no retransplantation was done and none of them showed evidence of disease recurrence (100% graft, patient and disease free survival). Our initial experience showed that Therasphere® is a promising therapeutic tool for both downstaging and bridging of HCC before liver transplant. Copyright © 2015 Elsevier Inc. All rights reserved.

Bridging Locoregional Therapy Prolongs Survival in Patients Listed for Liver Transplant with Hepatocellular Carcinoma

Energy Technology Data Exchange (ETDEWEB)

Xing, Minzhi [Yale School of Medicine, Interventional Radiology, Department of Radiology and Biomedical Imaging (United States); Sakaria, Sonali [Emory University School of Medicine, Division of Digestive Diseases, Department of Medicine (United States); Dhanasekaran, Renumathy [Stanford University School of Medicine, Division of Gastroenterology and Hepatology (United States); Parekh, Samir; Spivey, James [Emory University School of Medicine, Division of Digestive Diseases, Department of Medicine (United States); Knechtle, Stuart J. [Duke University School of Medicine, Division of Transplant Surgery, Department of Surgery (United States); Zhang, Di [University of Pittsburgh, Department of Biostatistics, Graduate School of Public Health (United States); Kim, Hyun S., E-mail: kevin.kim@yale.edu [Yale School of Medicine, Interventional Radiology, Department of Radiology and Biomedical Imaging (United States)

2017-03-15

Background and AimsTo evaluate the long-term survival benefit of bridging locoregional therapy (LRT) prior to orthotopic liver transplantation (OLT) in patients with hepatocellular carcinoma (HCC) within Milan criteria.MethodsOur transplant center registry was studied for all HCC patients within the Milan criteria who were listed for OLT from 1998 to 2013. Baseline clinical characteristics and median overall survival (OS) were calculated and stratified by LRT, OLT status, and wait times. Survival analysis was conducted using Kaplan–Meier estimation and log-rank test.ResultsOf 265 listed, 205 underwent OLT (mean follow-up 7.6 years). Of 205, 111 received bridging LRT (A), and 94 did not (B). Both were similar in demographics and tumor characteristics (p > 0.05). Median OS from HCC for A/B were 86.4 vs. 68.9 months (p = 0.01). Median OS from OLT for A/B were 74.6 vs. 63.6 months (p = 0.03). On multivariate analysis, independent predictors for survival from HCC were bridging LRT (p = 0.002) and high wait time (p = 0.008); independent predictors for survival from OLT were bridging LRT (p = 0.005) and high wait time (p = 0.005). Of 60 who were listed but did not undergo transplant, 44 received LRT (C) and 16 received best supportive care (D). Median OS from HCC for C/D were 37.1 vs. 24.8 months (p = 0.03).ConclusionsBridging LRT and high wait times were independent positive prognostic factors for survival from HCC diagnosis and OLT.

Bridging Locoregional Therapy Prolongs Survival in Patients Listed for Liver Transplant with Hepatocellular Carcinoma

International Nuclear Information System (INIS)

Xing, Minzhi; Sakaria, Sonali; Dhanasekaran, Renumathy; Parekh, Samir; Spivey, James; Knechtle, Stuart J.; Zhang, Di; Kim, Hyun S.

2017-01-01

Background and AimsTo evaluate the long-term survival benefit of bridging locoregional therapy (LRT) prior to orthotopic liver transplantation (OLT) in patients with hepatocellular carcinoma (HCC) within Milan criteria.MethodsOur transplant center registry was studied for all HCC patients within the Milan criteria who were listed for OLT from 1998 to 2013. Baseline clinical characteristics and median overall survival (OS) were calculated and stratified by LRT, OLT status, and wait times. Survival analysis was conducted using Kaplan–Meier estimation and log-rank test.ResultsOf 265 listed, 205 underwent OLT (mean follow-up 7.6 years). Of 205, 111 received bridging LRT (A), and 94 did not (B). Both were similar in demographics and tumor characteristics (p > 0.05). Median OS from HCC for A/B were 86.4 vs. 68.9 months (p = 0.01). Median OS from OLT for A/B were 74.6 vs. 63.6 months (p = 0.03). On multivariate analysis, independent predictors for survival from HCC were bridging LRT (p = 0.002) and high wait time (p = 0.008); independent predictors for survival from OLT were bridging LRT (p = 0.005) and high wait time (p = 0.005). Of 60 who were listed but did not undergo transplant, 44 received LRT (C) and 16 received best supportive care (D). Median OS from HCC for C/D were 37.1 vs. 24.8 months (p = 0.03).ConclusionsBridging LRT and high wait times were independent positive prognostic factors for survival from HCC diagnosis and OLT.

Bridges and Barriers to Developing and Conducting Interdisciplinary Graduate-Student Team Research

Directory of Open Access Journals (Sweden)

Wayde Cameron. Morse

2007-12-01

Full Text Available Understanding complex socio-environmental problems requires specialists from multiple disciplines to integrate research efforts. Programs such as the National Science Foundation's Integrative Graduate Education and Research Traineeship facilitate integrated research efforts and change the way academic institutions train future leaders and scientists. The University of Idaho and the Tropical Agricultural Research and Higher Education Center in Costa Rica collaborate on a joint research program focusing on biodiversity conservation and sustainable production in fragmented landscapes. We first present a spectrum of integration ranging from disciplinary to transdisciplinary across seven aspects of the research process. We then describe our experiences and lessons learned conducting interdisciplinary graduate student team research. Using our program as a case study, we examine the individual, disciplinary, and programmatic bridges and barriers to conducting interdisciplinary research that emerged during our student team research projects. We conclude with a set of recommendations for exploiting the bridges and overcoming the barriers to conducting interdisciplinary research, especially as part of graduate education programs.

TMACS test procedure TP012: Panalarm software bridge

International Nuclear Information System (INIS)

Washburn, S.J.

1994-01-01

This Test Procedure addresses the testing of the functionality of the Tank Monitor and Control System (TMACS) Panalarm bridge software. The features to be tested are: Bridge Initialization Options; Bridge Communication; Bridge Performance; Testing Checksum Errors; and Testing Command Reject Errors. Only the first three could be tested; the last two have been deferred to a later date

Running Safety of Trains under Vessel-Bridge Collision

Directory of Open Access Journals (Sweden)

Yongle Li

2015-01-01

Full Text Available To optimize the sensor placement of the health monitoring system, the dynamic behavior of the train-bridge system subjected to vessel-collision should be studied in detail firstly. This study thus focuses on the characteristics of a train-bridge system under vessel-bridge collision. The process of the vessel-bridge collision is simulated numerically with a reliable finite element model (FEM. The dynamic responses of a single car and a train crossing a cable-stayed bridge are calculated. It is shown that the collision causes significant increase of the train’s lateral acceleration, lateral wheelset force, wheel unloading rate, and derailment coefficient. The effect of the collision on the train’s vertical acceleration is much smaller. In addition, parametric studies with various train’s positions, ship tonnage, and train speed are performed. If the train is closer to the vessel-bridge collision position or the ship tonnage is larger, the train will be more dangerous. There is a relatively high probability of running danger at a low speed, resulting from longer stay of the train on the bridge. The train’s position, the ship tonnage, and the train speed must be considered when determining the most adverse conditions for the trains running on bridges under vessel-bridge collision.

Fatigue test on aluminium bridges

NARCIS (Netherlands)

Maljaars, J.; Soetens, F.; Straalen, van IJ.J.

2005-01-01

Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge

Vulnerability of bridges to fire

DEFF Research Database (Denmark)

Giuliani, Luisa; Crosti, C.; Gentili, F.

2012-01-01

Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also endan...

Bridge employment after early retirement: a bridge to better postretirement well-being of older adults?

NARCIS (Netherlands)

Dingemans, E.

2012-01-01

Using a retirement arrangement does not necessarily mean that people retire fulltime. The phenomenon of bridge employment, already studied in the US, becomes increasingly popular among older adults in the Netherlands. The question is to what extent bridge employment can be beneficial for well-being

A Simple and Universal Resistive-Bridge Sensors Interface

Directory of Open Access Journals (Sweden)

Sergey Y. YURISH

2011-02-01

Full Text Available Resistive-bridge sensors are widely used in various sensor systems. There are many sensor signal conditioners from different manufacturers for such sensing elements. However, no one existing on the modern market integrated converter for resistive bridge sensors can work with both: resistive-bridge sensing elements and resistive-to-frequency and -duty-cycle converters’ outputs. A proposed and described in the article universal interface for resistive-bridge sensing elements and bridge-output-to-frequency and/or duty cycle converters based on the designed Universal Sensors and Transducers Interface (USTI integrated. It is based on a simple, cost effective three-point measuring technique and does not require any additional active components. The USTI IC is realized in a standard CMOS technology. The active supply current at operating voltage +4.5 V and clock frequency 20 MHz is not more than 9.5 mA This paper reports experimental results with a strain gauges bridge emulator and differential pressure resistive bridge sensor SX30GD2.

Prestressed concrete cable-stayed bridge; PC shachokyo `Tajiri sky bridge` no seko

Energy Technology Data Exchange (ETDEWEB)

Kaida, Y.; Tsujino, F. [Osaka Prefectural Government Office, Osaka (Japan); Yamamoto, T.; Hishiki, Y.; Saito, K.

1995-01-30

The outline on the execution of PC cable-stayed bridge `Tajiri Sky Bridge` which was built at the opposite coast of Kansai International Airport was reported. This bridge is a double-sided suspension PC cable-stayed bridge with a tower height of 93.6 m having a main beam which is 26.3 m wide, featuring H-type main tower with one side beam, a smooth main beam structure, the leg top part with a large section, etc. A large-capacity factory manufacturing type non-grout cable with a pull strength of 1,900 ton class was adopted for the diagonal bracing. The leg top part is in a massive concrete structure so that, for avoiding the crack of cement due to temperature, a low heat build-up furnace cement was adopted, the water reducing agent was used, pre-cooling and side-clamping PC steel material were adopted and moderate pre-stress was introduced. In the execution of the connection part of the main beam, for preventing the deflection fluctuation due to the change of the main beam/main tower/diagonal bracing due to temperature and vibration due to wind, the earth anchor was used to tentatively fix the extended part. During execution, the wind velocity was strong reaching 25 m/s, which did not produce any problems. 1 ref., 24 figs., 3 tabs.

BRIDGES for Young Adolescents in North Dakota.

Science.gov (United States)

Harris, Mary McDonnell

The BRIDGES Project was initiated to explore ways for North Dakota to provide young people with stronger bridges from childhood to adulthood. This report summarizes recommendations of the 1990-91 Governor's Task Force on Early Adolescence. The recommendations concern practical actions for the building of bridges by the following groups: (1)…

Lifetime Reliability Assessment of Concrete Slab Bridges

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

A procedure for lifetime assesment of the reliability of short concrete slab bridges is presented in the paper. Corrosion of the reinforcement is the deterioration mechanism used for estimating the reliability profiles for such bridges. The importance of using sensitivity measures is stressed....... Finally the produce is illustrated on 6 existing UK bridges....

33 CFR 165.1187 - Security Zones; Golden Gate Bridge and the San Francisco-Oakland Bay Bridge, San Francisco Bay...

Science.gov (United States)

2010-07-01

... Limited Access Areas Eleventh Coast Guard District § 165.1187 Security Zones; Golden Gate Bridge and the... Golden Gate Bridge and the San Francisco-Oakland Bay Bridge, in San Francisco Bay, California. (b... siren, radio, flashing light, or other means, the operator of a vessel shall proceed as directed. [COTP...

Fe2(AsO4)F: A new three-dimensional condensed fluoro-arsenate iron(II) compound with antiferromagnetic interactions

International Nuclear Information System (INIS)

Berrocal, Teresa; Mesa, Jose L.; Pizarro, Jose L.; Urtiaga, Miren K.; Arriortua, Maria I.; Rojo, Teofilo

2006-01-01

Fe 2 (AsO 4 )F has been synthesized under mild hydrothermal conditions in the form of single crystals. The compound crystallizes in C2/c monoclinic space group with the unit cell parameters a=13.214(1), b=6.623(1), c=10.045(1)A and β=116.90(2) deg. with Z=8. The crystal structure consists of a three-dimensional framework constructed by two kinds of chains, A and B, with 50% of population. In the chains, the environments for the iron(II) cations show penta- and hexa-coordination. The chains establish an angle of approximately 120 deg. between them. The disordered fluoride anions in these chains given rise to [Fe(1)O 4 F(1) 0.5 (F(2) 0.5 ) 2 ] and [Fe(2)O 4 (F(1) 0.5 ) 2 F(2) 0.5 ] edge-shared polyhedra in which the fluoride anions have occupancy factors of 50% over two distinct crystallographic sites. The IR spectrum shows the characteristic bands of the (AsO 4 ) 3- groups. From the diffuse reflectance spectrum a D q parameter of 650cm -1 has been calculated for the Fe(II) d 6 high spin cation. The Mossbauer spectrum in the paramagnetic state shows a doublet that has been fitted, according to the existence of two crystallographically independent iron environments, with two Lorentzian doublets. Magnetic measurements performed between room temperature and 5K exhibit a maximum at 22.6K, characteristic of antiferromagnetic interactions with a estimated 'J'-exchange parameter of -1.2K

Wind tunnel test of musi VI bridge

Science.gov (United States)

Permata, Robby; Andika, Matza Gusto; Syariefatunnisa, Risdhiawan, Eri; Hermawan, Budi; Noordiana, Indra

2017-11-01

Musi VI Bridge is planned to cross the Musi River in Palembang City, South Sumatera Province, Indonesia. The main span is a steel arch type with 200 m length and side span length is 75 m. Finite element analysis results showed that the bridge has frequency ratio for torsional and heaving mode (torsional frequency/heaving frequency)=1.14. This close to unity value rises concern about aerodynamic behaviour and stability of the bridge deck under wind loading. Sectional static and free vibration wind tunnel test were performed to clarify this phenomena in B2TA3 facility in Serpong, Indonesia. The test followed the draft of Guide of Wind Tunnel Test for Bridges developed by Indonesian Ministry of Public Works. Results from wind tunnel testing show that the bridge is safe from flutter instability and no coupled motion vibration observed. Therefore, low value of frequency ratio has no effect to aerodynamic behaviour of the bridge deck. Vortex-induced vibration in heaving mode occurred in relatively low wind velocity with permissible maximum amplitude value.

Methanol, Ethanol and Propanol in EHD liquid bridging

International Nuclear Information System (INIS)

Fuchs, Elmar C; Wexler, Adam D; Agostinho, Luewton L F; Ramek, Michael; Woisetschläger, Jakob

2011-01-01

When a high-voltage direct-current is applied to two beakers filled with water or polar liquid dielectrica, a horizontal bridge forms between the two beakers. In this work such bridges made of methanol, ethanol, 1-propanol and 2-propanol are investigated with polarimetry and thermography. Whereas methanol, ethanol and 1-propanol bridges become warm like a water bridge, a 2-propanol bridge cools down relative to the surroundings. It is shown how the different stability of the primary and secondary alcoholate ions and the resulting small difference in conductivity between 1-propanol and 2-propanol is responsible for this novel effect.

The shape, stability and breakage of pendant liquid bridges

Science.gov (United States)

Padday, J. F.; Pétré, G.; Rusu, C. G.; Gamero, J.; Wozniak, G.

1997-12-01

Pendant liquid bridges are defined as pendant drops supporting a solid axisymmetric endplate at their lower end. The stability and shape properties of such bridges are defined in terms of the capillary properties of the system and of the mass and radius of the lower free-floating endplate. The forces acting in the pendant liquid bridge are defined exactly and expressed in dimensionless form. Numerical analysis has been used to derive the properties of a given bridge and it is shown that as the bridge grows by adding more liquid to the system a maximum volume is reached. At this maximum volume, the pendant bridge becomes unstable with the length of the bridge increasing spontaneously and irreversibly at constant volume. Finally the bridge breaks with the formation of a satellite drop or an extended thread. The bifurcation and breakage processes have been recorded using a high-speed video camera with a digital recording rate of up to 6000 frames per second. The details of the shape of the bridge bifurcation and breakage for many pendant bridge systems have been recorded and it is shown that satellite drop formation after rupture is not always viscosity dependent. Bifurcation and breakage in simulated low gravity demonstrated that breakage was very nearly symmetrical about a plane through the middle of the pendant bridge.

Seismic response computations for a long span bridge

International Nuclear Information System (INIS)

McCallen, D.B.

1994-01-01

The authors are performing large-scale numerical computations to simulate the earthquake response of a major long-span bridge that crosses the San Francisco Bay. The overall objective of the study is to estimate the response of the bridge to potential large-magnitude earthquakes generated on the nearby San Andreas and Hayward earthquake faults. Generation of a realistic model of the bridge system is complicated by the existence of large pile group foundations that extend deep into soft, saturated clay soils, and by the numerous expansion joints that segment the overall bridge structure. In the current study, advanced, nonlinear, finite element technology is being applied to rigorously model the detailed behavior of the bridge system and to shed light on the influence of the foundations and joints of the bridge

Shear evaluation of tapered bridge girder panels with steel corrugated webs near the supports of continuous bridges

OpenAIRE

Zevallos, E.; Hassanein, M.F.; Real Saladrigas, Esther; Mirambell Arrizabalaga, Enrique

2016-01-01

Because of public construction budgets were cut over the last few years, new bridge girders with corrugated webs to reduce the construction costs have become more widely studied and used. In spite that tapered bridge girders with corrugated webs (BGCWs) are used in modern bridges, their shear strength and behaviour rarely exists in literature. Based on available literature, the web of the linearly tapered BGCWs may be divided into three typologies with different structural response to shear f...

Blasting detonators incorporating semiconductor bridge technology

Energy Technology Data Exchange (ETDEWEB)

Bickes, R.W. Jr.

1994-05-01

The enormity of the coal mine and extraction industries in Russia and the obvious need in both Russia and the US for cost savings and enhanced safety in those industries suggests that joint studies and research would be of mutual benefit. The author suggests that mine sites and well platforms in Russia offer an excellent opportunity for the testing of Sandia`s precise time-delay semiconductor bridge detonators, with the potential for commercialization of the detonators for Russian and other world markets by both US and Russian companies. Sandia`s semiconductor bridge is generating interest among the blasting, mining and perforation industries. The semiconductor bridge is approximately 100 microns long, 380 microns wide and 2 microns thick. The input energy required for semiconductor bridge ignition is one-tenth the energy required for conventional bridgewire devices. Because semiconductor bridge processing is compatible with other microcircuit processing, timing and logic circuits can be incorporated onto the chip with the bridge. These circuits can provide for the precise timing demanded for cast effecting blasting. Indeed tests by Martin Marietta and computer studies by Sandia have shown that such precise timing provides for more uniform rock fragmentation, less fly rock, reduce4d ground shock, fewer ground contaminants and less dust. Cost studies have revealed that the use of precisely timed semiconductor bridges can provide a savings of $200,000 per site per year. In addition to Russia`s vast mineral resources, the Russian Mining Institute outside Moscow has had significant programs in rock fragmentation for many years. He anticipated that collaborative studies by the Institute and Sandia`s modellers would be a valuable resource for field studies.

0-6722 : spread prestressed concrete slab beam bridges.

Science.gov (United States)

2014-08-01

The Texas Department of Transportation uses : precast prestressed concrete slab beam bridges for : shorter-span bridges of approximately 3050 ft in : length. Conventional slab beam bridges have slab : beams placed immediately adjacent to one anoth...

Building Bridges One Line at a Time

Science.gov (United States)

Grigsby, Cathy Murray

2012-01-01

In this article, first-grade students were taught the different kinds of lines that were part of the construction of various bridges--the curved lines of the arches of stone bridges, straight lines connecting the cables of a suspension bridge, vertical lines, horizontal lines, and so on. They gained practice in drawing structures and in fine brush…

SURVEY RESULTS AND TESTING OF RAILWAY BRIDGES

Directory of Open Access Journals (Sweden)

I. H. Haniiev

2010-03-01

Full Text Available The article is devoted to the survey and testing of railway bridges by the State Joint-Stock Railway Company «Uzbekiston Temir Yollari» («Uzbekistan Railways». It is stated that in the existing rules on determination of the capacity of bridges the recommendations on taking into account the cumulative deflection to the moment of technical diagnostics of spans on the bridge capacity are absent. The author states on the need to develop a method for determining the wear of spans on restriction of the residual deflection in the bridge floor slabs.

23 CFR 650.705 - Application for discretionary bridge funds.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Application for discretionary bridge funds. 650.705... TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650.705 Application for discretionary bridge funds. Each year through its field offices, the FHWA will...

New conceptual design of portable bamboo bridge for emergency purposes

Science.gov (United States)

Musthaffa, A. A.; Nor, N. M.; Yusof, M. A.; Yuhazri, M. Y.

2018-02-01

Portable bridges serve as routes for troops during the military operations and the disaster relief operation. Nowadays, bamboo has been regarded as one of the alternative construction materials for building and bridge structures. This paper presents the conceptual design of the portable bridge. Several types of portable bridges and bamboo bridges are reviewed in the current work. The characteristics, capability and method of construction of each bridge are discussed. Finally, the conceptual of the portable bamboo bridge for emergency purposes is presented. The idea of producing portable bridge is proposed in the current work as it is crucial for providing route for communities affected by natural disasters.

A cloud-based information repository for bridge monitoring applications

Science.gov (United States)

Jeong, Seongwoon; Zhang, Yilan; Hou, Rui; Lynch, Jerome P.; Sohn, Hoon; Law, Kincho H.

2016-04-01

This paper describes an information repository to support bridge monitoring applications on a cloud computing platform. Bridge monitoring, with instrumentation of sensors in particular, collects significant amount of data. In addition to sensor data, a wide variety of information such as bridge geometry, analysis model and sensor description need to be stored. Data management plays an important role to facilitate data utilization and data sharing. While bridge information modeling (BrIM) technologies and standards have been proposed and they provide a means to enable integration and facilitate interoperability, current BrIM standards support mostly the information about bridge geometry. In this study, we extend the BrIM schema to include analysis models and sensor information. Specifically, using the OpenBrIM standards as the base, we draw on CSI Bridge, a commercial software widely used for bridge analysis and design, and SensorML, a standard schema for sensor definition, to define the data entities necessary for bridge monitoring applications. NoSQL database systems are employed for data repository. Cloud service infrastructure is deployed to enhance scalability, flexibility and accessibility of the data management system. The data model and systems are tested using the bridge model and the sensor data collected at the Telegraph Road Bridge, Monroe, Michigan.

The I-35W bridge Project Website

DEFF Research Database (Denmark)

Kampf, Constance

How can websites be used to rebuild trust?  In August 2007, the Interstate Highway 35-W bridge in Minneapolis, MN collapsed during rush hour.  Although many people were rescued and casualties were as limited as could be expected due to quick and effective intervention, the image of a major bridge...... collapsing during rush hour damaged the Minnesota Department of Transportation's reputation and resulted in the loss of public trust for the organization.  The ensuing bridge reconstruction project included a project website intended to rebuild this trust through transparency, community involvement......, and the use of multimodal features.  This paper looks at the I35-W bridge reconstruction project in Minneapolis through web-based communication by the Minnesota Department of Transportation (MnDOT) about the project. The MnDOT bridge reconstruction website will be examined using a combination of 1). Weick...

Benefits of ambulatory axillary intra-aortic balloon pump for circulatory support as bridge to heart transplant.

Science.gov (United States)

Umakanthan, Ramanan; Hoff, Steven J; Solenkova, Natalia; Wigger, Mark A; Keebler, Mary E; Lenneman, Andrew; Leacche, Marzia; Disalvo, Thomas G; Ooi, Henry; Naftilan, Allen J; Byrne, John G; Ahmad, Rashid M

2012-05-01

Axillary intra-aortic balloon pump therapy has been described as a bridge to transplant. Advantages over femoral intra-aortic balloon pump therapy include reduced incidence of infection and enhanced patient mobility. We identified the patients who would benefit most from this therapy while awaiting heart transplantation. We conducted a single-center, retrospective observational study to evaluate outcomes from axillary intra-aortic balloon pump therapy. These included hemodynamic parameters, duration of support, and success in bridging to transplant. We selected patients on the basis of history of sternotomy, elevated panel-reactive antibody, and small body habitus. Patients were made to ambulate aggressively beginning on postoperative day 1. Between September 2007 and September 2010, 18 patients underwent axillary intra-aortic balloon pump therapy. All patients had the devices placed through the left axillary artery with a Hemashield side graft (Boston Scientific, Natick, Mass). Before axillary placement, patients underwent femoral placement to demonstrate hemodynamic benefit. Duration of support ranged from 5 to 63 days (median = 19 days). There was marked improvement in ambulatory potential and hemodynamic parameters, with minimal blood transfusion requirements. There were no device-related infections. Some 72% of the patients (13/18) were successfully bridged to transplantation. Axillary intra-aortic balloon pump therapy provides excellent support for selected patients as a bridge to transplant. The majority of the patients were successfully bridged to transplant and discharged. Although this therapy has been described in previous studies, this is the largest series to incorporate a regimen of aggressive ambulation with daily measurements of distances walked. Copyright © 2012. Published by Mosby, Inc.

Investigation on the performance of bridge approach slab

Directory of Open Access Journals (Sweden)

Abdelrahman Amr

2018-01-01

Full Text Available In Egypt, where highway bridges are to be constructed on soft cohesive soils, the bridge abutments are usually founded on rigid piles, whereas the earth embankments for the bridge approaches are directly founded on the natural soft ground. Consequently, excessive differential settlement frequently occurs between the bridge deck and the bridge approaches resulting in a “bump” at both ends of the bridge deck. Such a bump not only creates a rough and uncomfortable ride but also represents a hazardous condition to traffic. One effective technique to cope with the bump problem is to use a reinforced concrete approach slab to provide a smooth grade transition between the bridge deck and the approach pavement. Investigating the geotechnical and structural performance of approach slabs and revealing the fundamental affecting factors have become mandatory. In this paper, a 2-D finite element model is employed to investigate the performance of approach slabs. Moreover, an extensive parametric study is carried out to appraise the relatively optimum geometries of approach slab, i.e. slab length, thickness, embedded depth and slope, that can yield permissible bumps. Different geo-mechanical conditions of the cohesive foundation soil and the fill material of the bridge embankment are examined.

History of cable-stayed bridges

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m in the Strö...

A Hierarchical Analysis of Bridge Decision Makers ... The Role of New Technology Adoption in the Timber Bridge Market: Special Project

Science.gov (United States)

Robert L. Smith; Robert J. Bush; Daniel L. Schmoldt

1995-01-01

Bridge design engineers and local highway officials make bridge replacement decisions across the United States. The Analytical Hierarchy Process was used to characterize the bridge material selection decision of these individuals. State Department of Transportation engineers, private consulting engineers, and local highway officials were personally interviewed in...

Intercellular bridges in vertebrate gastrulation.

Directory of Open Access Journals (Sweden)

Luca Caneparo

Full Text Available The developing zebrafish embryo has been the subject of many studies of regional patterning, stereotypical cell movements and changes in cell shape. To better study the morphological features of cells during gastrulation, we generated mosaic embryos expressing membrane attached Dendra2 to highlight cellular boundaries. We find that intercellular bridges join a significant fraction of epiblast cells in the zebrafish embryo, reaching several cell diameters in length and spanning across different regions of the developing embryos. These intercellular bridges are distinct from the cellular protrusions previously reported as extending from hypoblast cells (1-2 cellular diameters in length or epiblast cells (which were shorter. Most of the intercellular bridges were formed at pre-gastrula stages by the daughters of a dividing cell maintaining a membrane tether as they move apart after mitosis. These intercellular bridges persist during gastrulation and can mediate the transfer of proteins between distant cells. These findings reveal a surprising feature of the cellular landscape in zebrafish embryos and open new possibilities for cell-cell communication during gastrulation, with implications for modeling, cellular mechanics, and morphogenetic signaling.

Characterization of bridge foundations workshop report.

Science.gov (United States)

2013-11-01

"In 2013, the Federal Highway Administration proposed a new research program for the characterization of bridge foundations. To narrow the focus and develop a research roadmap for the program, a workshop on Characterization of Bridge Foundations...

A highly sensitive amperometric sensor for oxygen based on iron(II) tetrasulfonated phthalocyanine and iron(III) tetra-(N-methyl-pyridyl)-porphyrin multilayers

International Nuclear Information System (INIS)

Duarte, Juliana C.; Luz, Rita C.S.; Damos, Flavio S.; Tanaka, Auro A.; Kubota, Lauro T.

2008-01-01

The development of a highly sensitive sensor for oxygen is proposed using a glassy carbon (GC) electrode modified with alternated layers of iron(II) tetrasulfonated phthalocyanine (FeTsPc) and iron(III) tetra-(N-methyl-pyridyl)-porphyrin (FeT4MPyP). The modified electrode showed excellent catalytic activity for the oxygen reduction. The reduction potential of the oxygen was shifted about 330 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare GC electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves 4 electrons with a heterogenous rate constant (k obs ) of 3 x 10 5 mol -1 L s -1 . A linear response range from 0.2 up to 6.4 mg L -1 , with a sensitivity of 4.12 μA L mg -1 (or 20.65 μA cm -2 L mg -1 ) and a detection limit of 0.06 mg L -1 were obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation (R.S.D.) was 2.0% for 10 measurements of a solution of 6.4 mg L -1 oxygen. The sensor was applied to determine oxygen in pond and tap water samples showing to be a promising tool for this purpose

An efficient CMOS bridging fault simulator with SPICE accuracy

NARCIS (Netherlands)

Di, C.; Jess, J.A.G.

1996-01-01

This paper presents an alternative modeling and simulation method for CMOS bridging faults. The significance of the method is the introduction of a set of generic-bridge tables which characterize the bridged outputs for each bridge and a set of generic-cell tables which characterize how each cell

33 CFR 118.110 - Daymarks and lateral lighting on bridges.

Science.gov (United States)

2010-07-01

... bridges. 118.110 Section 118.110 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.110 Daymarks and lateral lighting on bridges. (a... through bridges with U.S. aids to navigation system lateral marks and lights installed on the...

Some aspects of technical models within bridge management system

Directory of Open Access Journals (Sweden)

Grković Slobodan

2015-01-01

Full Text Available Bridge Management System (BMS represents a rational and systematic approach to organizing and conducting of all activities related to bridge maintenance. Main goal of BMS is helping the bridge owner to make an optimal decision with respect to bridge maintenance budget, whether it is dedicated to one bridge or to group of bridges, by securing that the decision is made on the basis of Life-Cycle Cost (LCC estimates. The structure of BMS is based on condition rating and Bridge Database (BD, Deterioration model (DM, Cost Model for evaluation of costs and Optimization Model for choosing the most rational maintenance strategy. Relationship between bridge condition rating and DM with maintenance costs within BMS is very important. Predictions regarding future intensity and rate of bridge deterioration depends on multitude of factors and it is a consequence of several simultaneous actions and deterioration processes (DP which need to be included into DMs. DMs are mostly based on modeling of physical and chemical actions and processes or they are based on statistical analysis of large number of data regarding the condition of existing bridges, or on artificial intelligence models, etc. Stochastic models based on Markov processes are applied within more advanced contemporary BMS. Due to social and economic circumstances and lack of financial resources over the last two decades in Republic of Serbia bridge maintenance was neglected and creation of BD was discontinued. The paper deliberates some aspects of technical models within BMS, with DMs being pointed out, development of BD within bridge maintenance in Republic of Serbia and it gives an overview of sophisticated BMS and current advances in this field.

Geometric phase and quantum interference in photosynthetic reaction center: Regulation of electron transfer

Energy Technology Data Exchange (ETDEWEB)

Sun, Yuming, E-mail: ymsun@ytu.edu.cn; Su, Yuehua; Dai, Zhenhong; Wang, WeiTian

2016-10-20

Photosynthesis is driven by electron transfer in reaction centers in which the functional unit is composed of several simple molecules C{sub 2}-symmetrically arranged into two branches. In view of quantum mechanism, both branches are possible pathways traversed by the transferred electron. Due to different evolution of spin state along two pathways in transmembrane electric potential (TEP), quantum state of the transferred electron at the bridged site acquires a geometric phase difference dependent on TEP, the most efficient electron transport takes place in a specific range of TEP beyond which electron transfer is dramatically suppressed. What’s more, reaction center acts like elaborately designed quantum device preparing polarized spin dependent on TEP for the transferred electron to regulate the reduction potential at bridged site. In brief, electron transfer generates the TEP, reversely, TEP modulates the efficiency of electron transfer. This may be an important approach to maintaining an appreciable pH environment in photosynthesis.

Monitoring system of arch bridge for safety network management

Science.gov (United States)

Joo, Bong Chul; Yoo, Young Jun; Lee, Chin Hyung; Park, Ki Tae; Hwang, Yoon Koog

2010-03-01

Korea has constructed the safety management network monitoring test systems for the civil infrastructure since 2006 which includes airport structure, irrigation structure, railroad structure, road structure, and underground structure. Bridges among the road structure include the various superstructure types which are Steel box girder bridge, suspension bridge, PSC-box-girder bridge, and arch bridge. This paper shows the process of constructing the real-time monitoring system for the arch bridge and the measured result by the system. The arch type among various superstructure types has not only the structural efficiency but the visual beauty, because the arch type superstructure makes full use of the feature of curve. The main measuring points of arch bridges composited by curved members make a difference to compare with the system of girder bridges composited by straight members. This paper also shows the method to construct the monitoring system that considers the characteristic of the arch bridge. The system now includes strain gauges and thermometers, and it will include various sensor types such as CCTV, accelerometers and so on additionally. For the long term and accuracy monitoring, the latest optical sensors and equipments are applied to the system.

A Comparison of Limb-Socket Kinematics of Bone-Bridging and Non-Bone-Bridging Wartime Transtibial Amputations

Science.gov (United States)

2012-05-16

each successive loading interval. Subset analysis was performed on the basis of amputation type (bone bridging or non bone bridging) and suspension...fitting, patient care. Washington, DC: US Government Printing Office; 1969. 2. Ertl J. Uber amputationsstumpfe. Chirurg. 1949;20:218 24. 3. Pinto MA

Demonstration and Validation of a Lightweight Composite Bridge Deck Technology as an Alternative to Reinforced Concrete

Science.gov (United States)

2016-08-01

Examples of the sensor placement are shown in Fig- ure 58 through Figure 60. A fully loaded dump truck weighing 78,660 lb was driven across the bridge at...release; distribution is unlimited. The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and...environmental challenges. ERDC develops innovative solutions in civil and military engineering , geospatial sciences, water resources, and

Suspension Bridge Flutter for Girder with Separate Control Flaps

DEFF Research Database (Denmark)

Huynh, T.; Thoft-Christensen, Palle

Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

Two high-frequency mutual inductance bridges with high resolution

NARCIS (Netherlands)

Flokstra, Jakob; Gerritsma, G.J.; Kreuwel, H.J.M.; van der Marel, L.C.

1980-01-01

Two mutual inductance bridges are described for operation up to about 100 kHz. Special attention is paid to the sensitivity and resolution of the bridges. Both bridges can be used to measure variations of about 10 pH in the mutual inductance. The first bridge consists of passive elements only

23 CFR 650.805 - Bridges not requiring a USCG permit.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Bridges not requiring a USCG permit. 650.805 Section 650... OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.805 Bridges not... permit is not required for bridge construction. This determination shall be made at an early stage of...

Using rotating liquid bridges as accelerometers

Energy Technology Data Exchange (ETDEWEB)

Montanero, J.M. [Universidad de Extremadura, Badajoz (Spain). Dept. de Electronica e Ingenieria Electromecanica; Cabezas, G.; Acero, J.; Zayas, F.

1999-07-01

Liquid bridges have recently been proposed as fluid accelerometers that could be used to measure very small inertial forces under microgravity conditions [Meseguer et al., microgravity sci. technol. IX/2 (1996)]. The essential idea is to infer the values of such inertial forces from the liquid bridge interface contour, whose shape obviously depends on the values of such forces (apart from the bridge volume and the geometry of the supporting disks). Following a similar procedure, in this paper we explore the use of rotating axisymmetric liquid bridges to measure the residual axial gravity and the rotation rate of the liquid bridge regarded as a solid body. In light off the difficulties involved in performing experiments on Earth, the role of empirical data is played by an accurate numerical solution of the Young-Laplace equation. The values of both the axial gravity and angular speed are obtained by fitting the approximate analytical expressions derived in this paper to the numerical solution of the Young-Laplace equation. The comparison between the predicted and actual values of the variables of interest shows a satisfactory agreement, supporting the suitability of the procedure. (orig.)

Advanced materials for control of post-earthquake damage in bridges

International Nuclear Information System (INIS)

Shrestha, Kshitij C; Saiidi, M Saiid; Cruz, Carlos A

2015-01-01

This paper presents analytical modeling to study the seismic response of bridge systems with conventional and advanced details. For validation, a 33 m quarter-scale model of a four-span bridge incorporating innovative materials and details seismically tested on the shake tables at the University of Nevada, Reno was taken. The bridge specimen involved use of advanced materials and details to reduce damage at plastic hinges and minimize residual displacements. A three-dimensional, nonlinear model incorporating the response of the innovative materials was developed to study the bridge response using the finite-element software OpenSees. Existing finite-element formulations were used to capture the response of the advanced materials used in the bridge. The analytical model was found to be able to reproduce comparable bent displacements and bent shear forces within reasonable accuracy. The validated model was further used to study different types of bridges under suite of scaled bi-directional near-fault ground motions. Comparisons were made on behavior of five different bridge types, first conventional reinforced concrete bridge, second post-tensioned column bridge, third bridge with elastomeric rubber elements at the plastic hinge zone, fourth bridge with nickel–titanium superelastic shape memory alloy (SMA) reinforcing bar and fifth bridge with CuAlMn superelastic SMA reinforcing bar. Both the SMA used bridges also utilized engineered cementitious composite element at the plastic hinge zone. The results showed effectiveness of the innovative interventions on the bridges in providing excellent recentering capabilities with minimal damage to the columns. (paper)

Building Bridges

DEFF Research Database (Denmark)

The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience......, Brian O’Neill, Andra Siibak, Sascha Trültzsch-Wijnen, Nicoletta Vittadini, Igor Vobič and Frauke Zeller. Stakeholder feedback from: Michelle Arlotta (DeAgostini), Andreea M. Costache (Association of Consumers of Audiovisual Media in Catalonia/TAC), Francesco Diasio (AMARC Europe), Marius Dragomir (Open...

Mathematical bridges

CERN Document Server

Andreescu, Titu; Tetiva, Marian

2017-01-01

Building bridges between classical results and contemporary nonstandard problems, Mathematical Bridges embraces important topics in analysis and algebra from a problem-solving perspective. Blending old and new techniques, tactics and strategies used in solving challenging mathematical problems, readers will discover numerous genuine mathematical gems throughout that will heighten their appreciation of the inherent beauty of mathematics. Most of the problems are original to the authors and are intertwined in a well-motivated exposition driven by representative examples. The book is structured to assist the reader in formulating and proving conjectures, as well as devising solutions to important mathematical problems by making connections between various concepts and ideas from different areas of mathematics. Instructors and educators teaching problem-solving courses or organizing mathematics clubs, as well as motivated mathematics students from high school juniors to college seniors, will find Mathematical Bri...

Free energy landscape of a minimalist salt bridge model.

Science.gov (United States)

Li, Xubin; Lv, Chao; Corbett, Karen M; Zheng, Lianqing; Wu, Dongsheng; Yang, Wei

2016-01-01

Salt bridges are essential to protein stability and dynamics. Despite the importance, there has been scarce of detailed discussion on how salt bridge partners interact with each other in distinct solvent exposed environments. In this study, employing a recent generalized orthogonal space tempering (gOST) method, we enabled efficient molecular dynamics simulation of repetitive breaking and reforming of salt bridge structures within a minimalist salt-bridge model, the Asp-Arg dipeptide and thereby were able to map its detailed free energy landscape in aqueous solution. Free energy surface analysis shows that although individually-solvated states are more favorable, salt-bridge states still occupy a noticeable portion of the overall population. Notably, the competing forces, e.g. intercharge attractions that drive the formation of salt bridges and solvation forces that pull the charged groups away from each other, are energetically comparable. As the result, the salt bridge stability is highly tunable by local environments; for instance when local water molecules are perturbed to interact more strongly with each other, the population of the salt-bridge states is likely to increase. Our results reveal the critical role of local solvent structures in modulating salt-bridge partner interactions and imply the importance of water fluctuations on conformational dynamics that involves solvent accessible salt bridge formations. © 2015 The Protein Society.

STUDY OF BRIDGE DECK A REVIEW

OpenAIRE

MISS. KSHITIJA S. BALWAN , MR. V. G. KHURD , MR. S. S. CHOUGULE

2018-01-01

The objective of this study was to understand the meaning of bridge deck. To know the different forms of decks used in bridge design. To understand different methods used for analysis of deck and study of box girder and its evolution

Strategic Planning for the National Bridge Stock of Iran

Directory of Open Access Journals (Sweden)

Ali Sahrapeyma

2013-06-01

Full Text Available The National Bridge Stock of Iran consists of about 330,000 bridges, of which around 50% are older than 30 years. Since 2010, Iran Road Maintenance & Transportation Organization has started implementing a comprehensive Bridge Management System in order to manage this aged stock efficiently. To predict future conditions of bridge stock, a heuristic numerical method is presented. This methodology is based on Markovian process to model deterioration of bridge decks and a multi-objective optimization problem to find the best solutions. The optimization problem involves three decision variables regarding management strategies, and has three objectives regarding cost minimization. Constraints of the problem are the percentage of deficient bridges, the percentage of bridges under MR&Rs (Maintenance, Repair and Rehabilitation and the average value of condition scores. The results show that to avoid future challenges, the annual budget for bridge maintenance should be increased, the current maintenance strategy should be improved as soon as possible, and national manuals and instructions for inspection, condition rating and maintenance should be developed.

Foot force models of crowd dynamics on a wobbly bridge.

Science.gov (United States)

Belykh, Igor; Jeter, Russell; Belykh, Vladimir

2017-11-01

Modern pedestrian and suspension bridges are designed using industry standard packages, yet disastrous resonant vibrations are observed, necessitating multimillion dollar repairs. Recent examples include pedestrian-induced vibrations during the opening of the Solférino Bridge in Paris in 1999 and the increased bouncing of the Squibb Park Bridge in Brooklyn in 2014. The most prominent example of an unstable lively bridge is the London Millennium Bridge, which started wobbling as a result of pedestrian-bridge interactions. Pedestrian phase locking due to footstep phase adjustment is suspected to be the main cause of its large lateral vibrations; however, its role in the initiation of wobbling was debated. We develop foot force models of pedestrians' response to bridge motion and detailed, yet analytically tractable, models of crowd phase locking. We use biomechanically inspired models of crowd lateral movement to investigate to what degree pedestrian synchrony must be present for a bridge to wobble significantly and what is a critical crowd size. Our results can be used as a safety guideline for designing pedestrian bridges or limiting the maximum occupancy of an existing bridge. The pedestrian models can be used as "crash test dummies" when numerically probing a specific bridge design. This is particularly important because the U.S. code for designing pedestrian bridges does not contain explicit guidelines that account for the collective pedestrian behavior.

Hierarchical analysis of bridge decision makers : the role of new technology adoption in the timber bridge market : special project fiscal year 1992

Science.gov (United States)

1995-08-01

Bridge design engineers and local highway officials make bridge replacement decisions across the : United States. The Analytical Hierarchy Process was used to characterize the bridge material selection : decision of these individuals. State Departmen...

Application of bridging-law concepts to short-fibre composites

DEFF Research Database (Denmark)

Lindhagen, J.E.; Gamstedt, Kristofer; Berglund, L.A.

2000-01-01

This is the third paper in a series of four where notch sensitivity, fracture energy and bridging laws are studied in short-fibre polymer composites. Here, bridging laws are derived from experimental crack-opening profiles in centre-hole notched tensile specimens. The materials studied are three...... types of commercial glass-mat composites with different reinforcement structures and matrices. The materials have softening bridging laws and the calculated fracture energies from bridging laws are in good agreement with values determined directly by experiment. The calculated maximum local bridging...

GaggleBridge: collaborative data analysis.

Science.gov (United States)

Battke, Florian; Symons, Stephan; Herbig, Alexander; Nieselt, Kay

2011-09-15

Tools aiding in collaborative data analysis are becoming ever more important as researchers work together over long distances. We present an extension to the Gaggle framework, which has been widely adopted as a tool to enable data exchange between different analysis programs on one computer. Our program, GaggleBridge, transparently extends this functionality to allow data exchange between Gaggle users at different geographic locations using network communication. GaggleBridge can automatically set up SSH tunnels to traverse firewalls while adding some security features to the Gaggle communication. GaggleBridge is available as open-source software implemented in the Java language at http://it.inf.uni-tuebingen.de/gb. florian.battke@uni-tuebingen.de Supplementary data are available at Bioinformatics online.

Seismic Performance of Multi-Span RC Railway Bridges

DEFF Research Database (Denmark)

Georgakis, Christos; Barrau, Xavier

2008-01-01

Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends – the Simply Supported Beam, Continuous Box-Girder (CBG), CBG...

Durability of Materials in Pearl-Chain Bridges

DEFF Research Database (Denmark)

Lund, Mia Schou Møller

. The construction of the Pearl-Chain arch is simple. The arch is assembled on its side, next to the road that the bridge will span, by placing a number of plane prefabricated Super-Light Decks that consist of lightweight aggregate concrete and conventional concrete, in the desired arch shape. Mortar joints are cast...... is stabilized by casting a fill material between the spandrel walls of the arch. Finally, the road surface is cast on top of the fill material. New bridges are designed for a service lifetime of at least 100 years. Hence, the specifications of the materials used in Pearl-Chain Bridges are high. This PhD study...... and pervious concrete were also investigated. The most suitable fill material for Pearl-Chain Bridges depends on the particular bridge design; the results obtained and presented in the present PhD study provide guidance on how to decide which fill material is most suitable regarding strength, permeability...

Chapter 10:Hardwoods for timber bridges

Science.gov (United States)

James P. Wacker; Ed T. Cesa

2005-01-01

This chapter describes the joint efforts of the Forest Service and the FHWA to administer national programs including research, demonstration bridges, and technology transfer components. Summary information on a number of Forest Service-WIT demonstration bridges constructed with hardwoods is also provided.

Identifying hidden sexual bridging communities in Chicago.

Science.gov (United States)

Youm, Yoosik; Mackesy-Amiti, Mary Ellen; Williams, Chyvette T; Ouellet, Lawrence J

2009-07-01

Bridge populations can play a central role in the spread of human immunodeficiency virus (HIV) by providing transmission links between higher and lower prevalence populations. While social network methods are well suited to the study of bridge populations, analyses tend to focus on dyads (i.e., risk between drug and/or sex partners) and ignore bridges between distinct subpopulations. This study takes initial steps toward moving the analysis of sexual network linkages beyond individual and risk group levels to a community level in which Chicago's 77 community areas are examined as subpopulations for the purpose of identifying potential bridging communities. Of particular interest are "hidden" bridging communities; that is, areas with above-average levels of sexual ties with other areas but whose below-average AIDS prevalence may hide their potential importance for HIV prevention. Data for this analysis came from the first wave of recruiting at the Chicago Sexual Acquisition and Transmission of HIV Cooperative Agreement Program site. Between August 2005 through October 2006, respondent-driven sampling was used to recruit users of heroin, cocaine, or methamphetamine, men who have sex with men regardless of drug use, the sex partners of these two groups, and sex partners of the sex partners. In this cross-sectional study of the sexual transmission of HIV, participants completed a network-focused computer-assisted self-administered interview, which included questions about the geographic locations of sexual contacts with up to six recent partners. Bridging scores for each area were determined using a matrix representing Chicago's 77 community areas and were assessed using two measures: non-redundant ties and flow betweenness. Bridging measures and acquired immunodeficiency syndrome (AIDS) case prevalence rates were plotted for each community area on charts representing four conditions: below-average bridging and AIDS prevalence, below-average bridging and above

Aesthetic coatings for concrete bridge components

Science.gov (United States)

Kriha, Brent R.

This thesis evaluated the durability and aesthetic performance of coating systems for utilization in concrete bridge applications. The principle objectives of this thesis were: 1) Identify aesthetic coating systems appropriate for concrete bridge applications; 2) Evaluate the performance of the selected systems through a laboratory testing regimen; 3) Develop guidelines for coating selection, surface preparation, and application. A series of site visits to various bridges throughout the State of Wisconsin provided insight into the performance of common coating systems and allowed problematic structural details to be identified. To aid in the selection of appropriate coating systems, questionnaires were distributed to coating manufacturers, bridge contractors, and various DOT offices to identify high performing coating systems and best practices for surface preparation and application. These efforts supplemented a literature review investigating recent publications related to formulation, selection, surface preparation, application, and performance evaluation of coating materials.

1,2-bridged quadricyclanes

International Nuclear Information System (INIS)

Hart, H.; Cheng-Tai Peng

1982-01-01

The readily available benzodihydropentalene 6 and dimethyl acetylenedicarboxylate react to give norbornadiene diester 8, with a three-carbon bridge from C 1 to C 2 . Irradiation of 8 gives the corresponding C 1 -C 2 bridged quadricyclane diester 9, a new ring system. Diester 9 is quite stable, reverting to 8 with a tsub(1/2) of 30 min at 170 0 C. The corresponding diacid 11, also prepared, reverts to its norbornadiene precursor at a considerably lower temperature, possibly as a consequence of acid catalysis. (author)

Influence of Icing on Bridge Cable Aerodynamics

DEFF Research Database (Denmark)

Koss, Holger; Frej Henningsen, Jesper; Olsen, Idar

2013-01-01

In recent years the relevance of ice accretion for wind-induced vibration of structural bridge cables has been recognised and became a subject of research in bridge engineering. Full-scale monitoring and observation indicate that light precipitation at moderate low temperatures between zero and -5......°C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion...... forces of different bridge cables types. The experiments were conducted in a wind tunnel facility capable amongst others to simulate incloud icing conditions....

Ambient Response Analysis of the Great Belt Bridge

DEFF Research Database (Denmark)

Brincker, Rune; Frandsen, Jeanette B.; Andersen, Palle

2000-01-01

In this paper an ambient response analysis of the Great Belt Bridge is presented. The Great Belt Bridge is one of the largest suspension bridges in the world, and the analysis was carried out in order to investigate the possibilities of estimating reliable damping values from the ambient response...

Ways of ensuring the standard of bridge superstructures.

OpenAIRE

M.G. Malgin; V.I. Kiryan

2011-01-01

The structural features of welded railway bridges of the last century were considered. The basic causes of appearance of fatigue cracks in welded joints of railway bridges were assessed. Structural and technological ways of provision of the design life of operated and new-built welded railway bridges are discussed.

OnWien Bridge Oscillators as Modified Multi-vibrators

DEFF Research Database (Denmark)

Lindberg, Erik

2014-01-01

A tutorial introduction to electrical oscilla- tors. Investigating Wien bridge oscillators as modified multi-vibrators. Introducing chaotic behavior into a Wien bridge oscillator by means of adding a simple nonlinear cir- cuit as a load of one of the amplifier input terminals......A tutorial introduction to electrical oscilla- tors. Investigating Wien bridge oscillators as modified multi-vibrators. Introducing chaotic behavior into a Wien bridge oscillator by means of adding a simple nonlinear cir- cuit as a load of one of the amplifier input terminals...

Bridge monitoring by interferometric deformation sensors

Science.gov (United States)

Inaudi, Daniele; Vurpillot, Samuel; Casanova, Nicoletta

1996-09-01

In many concrete bridges, the deformations are the most relevant parameter to be monitored in both short and long- terms. Strain monitoring gives only local information about the material behavior and too many such sensors would therefore be necessary to gain a complete understanding of the bridge behavior. We have found that fiber optic deformation sensors, with measurement bases of the order of one to a few meters, can give useful information both during the first days after concrete pouring and in the long term. In a first phase it is possible to monitor the thermal expansion due to the exothermic setting reaction and successively the thermal and drying shrinkages. Thanks to the long sensor basis, the detection of a crack traverse to the measurement region becomes probable and the evolution of cracks can therefore be followed with a reduced number of sensors. In the long-term it is possible to measure the geometric deformations and therefore the creeping of the bridge under static loads, especially under its own weight. In the past two years, our laboratory has installed hundreds of fiber optic deformation sensors in more than five concrete, composite steel-concrete, refurbished and enlarged bridges (road, highway and railway bridges). The measuring technique relies on low-coherence interferometry and offers a resolution down to a few microns even for long-term measurements. This contribution briefly discusses the measurement technique and then focuses on the development of a reliable sensor for direct concrete embedding and on the experimental results obtained on these bridges.

Guanidinium-Induced Denaturation by Breaking of Salt Bridges.

Science.gov (United States)

Meuzelaar, Heleen; Panman, Matthijs R; Woutersen, Sander

2015-12-07

Despite its wide use as a denaturant, the mechanism by which guanidinium (Gdm(+) ) induces protein unfolding remains largely unclear. Herein, we show evidence that Gdm(+) can induce denaturation by disrupting salt bridges that stabilize the folded conformation. We study the Gdm(+) -induced denaturation of a series of peptides containing Arg/Glu and Lys/Glu salt bridges that either stabilize or destabilize the folded conformation. The peptides containing stabilizing salt bridges are found to be denatured much more efficiently by Gdm(+) than the peptides containing destabilizing salt bridges. Complementary 2D-infrared measurements suggest a denaturation mechanism in which Gdm(+) binds to side-chain carboxylate groups involved in salt bridges. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurements of bridges' vibration characteristics using a mobile phone

Directory of Open Access Journals (Sweden)

Z. M. C. Pravia

Full Text Available ABSTRACTThis research presents an alternative way to perform a bridge inspection, which considers the dynamics parameters from the structure. It shows an experimental phase with use of a mobile phone to extract the accelerations answers from two concrete bridges, from those records is feasible to obtain natural frequencies using the Fast Fourier Transform (FFT.Numerical models with uses finite element model (FEM allow to determine the natural frequencies from the two concrete bridges and compare with the experimental phase of each one. The final results shows it's possible to use mobiles phones to extract vibration answers from concrete bridges and define the structural behavior of bridges from natural frequencies, this procedure could be used to evaluate bridges with lower costs.

Gust loading on streamlined bridge decks

DEFF Research Database (Denmark)

Larose, Guy; Mann, Jakob

1998-01-01

The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin...... of the analytical prediction methods. In this paper, an analytical model that departs from the strip assumption is used to describe the gust loading on a thin airfoil. A parallel is drawn between the analytical model and direct measurements of gust loading on motionless closed-box girder bridge decks. Empirical...

Resin-Bonded Bridges in vitro and in vivo

NARCIS (Netherlands)

Veen, Johannes Hilbrandt van der

1988-01-01

In this thesis in vitro and in vivo studies on the clinical application of resin-bonded bridges are described and discussed. The development of different types of resin-bonded bridges is described in chapter 1. The bridges are often made by boding a cast metal retainer fitted with and artificial

IceBridge Data Management and Access Strategies at NSIDC

Science.gov (United States)

Oldenburg, J.; Tanner, S.; Collins, J. A.; Lewis, S.; FitzGerrell, A.

2013-12-01

NASA's Operation IceBridge (OIB) mission, initiated in 2009, collects airborne remote sensing measurements over the polar regions to bridge the gap between NASA's Ice, Cloud and Land Elevation satellite (ICESat) mission and the upcoming ICESat-2 mission in 2016. OIB combines an evolving mix of instruments to gather data on topography, ice and snow thickness, high-resolution photography, and other properties that are more difficult or impossible to measure via satellite. Once collected, these data are stored and made available at the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado. To date, there are nearly 90 terabytes of data available, and there are about three more years of data collection left. The main challenges faced in data management at NSIDC are derived from the quantity and heterogeneity of the data. To deal with the quantity of data, the technical teams at NSIDC have significantly automated the data ingest, metadata generation, and other required data management steps. Heterogeneity of data and the evolution of the Operation over time make technical automation complex. To limit complexity, the IceBridge team has agreed to such practices as using specific data file formats, limiting file sizes, using specific filename templates, etc. These agreements evolve as Operation IceBridge moves forward. The metadata generated about the flights and the data collected thereon make the storage of the data more robust, and enable data discoverability. With so much metadata, users can search the vast collection with ease using specific parameters about the data they seek. An example of this in action is the IceBridge data portal developed at NSIDC, http://nsidc.org/icebridge/portal/. This portal uses the GPS data from the flights projected onto maps as well as other flight and instrument metadata to help the user find the exact data file they seek. This implementation is only possible with dependable data management beneath the surface. The data files

Performance indicators for roadway bridges

OpenAIRE

Strauss, A.; Vidovic, A.; Zambon, I.; Dengg, F.; Tanasic, N.; Matos, José C.

2016-01-01

Publicado em "Maintenance, monitoring, safety, risk and resilience of bridges and bridge networks". ISBN 978-1-138-02851-7 The performance indicators should, by its definition, allow capturing the life-cycle degradation processes affecting maintenance plans or the remaining lifetime. The qualitative or quantitative performance indicators are obtained through visual inspections, non-destructive tests or monitoring systems. After their quantification and the comparison with the resp...

Probabilistic and sensitivity analysis of Botlek Bridge structures

Directory of Open Access Journals (Sweden)

Králik Juraj

2017-01-01

Full Text Available This paper deals with the probabilistic and sensitivity analysis of the largest movable lift bridge of the world. The bridge system consists of six reinforced concrete pylons and two steel decks 4000 tons weight each connected through ropes with counterweights. The paper focuses the probabilistic and sensitivity analysis as the base of dynamic study in design process of the bridge. The results had a high importance for practical application and design of the bridge. The model and resistance uncertainties were taken into account in LHS simulation method.

Shaking Table Tests of Curved Bridge considering Bearing Friction Sliding Isolation

Directory of Open Access Journals (Sweden)

Lei Yan

2016-01-01

Full Text Available Specific to severe damage to curved bridges in earthquakes caused by the excessive force of the fixed bearings and piers, a new seismic design method on curved bridges considering bearing friction sliding isolation is proposed in this paper. Seismic model bridge and isolation model bridge with similarity ratio of 1/20 were made and the shaking table comparison test was conducted. The experimental results show that the isolation model curved bridge suffered less seismic damage than the seismic model curved bridge. The fundamental frequencies of the seismic model bridge and isolation model bridge decreased and the damping ratio increased with the increase of seismic intensity. Compared with seismic curved bridge, the maximum reduction rates of peak acceleration along the radial and tangential directions on the top of pier of the isolation model curved bridge were 47.3% and 55.5%, respectively, and the maximum reduction rate of the peak strain on the bottom of pier of the isolation model curved bridge was 43.4%. For the isolation model curved bridge, the maximum reduction rate of peak acceleration on the top of pier was 24.6% compared with that on the bottom of pier. The study results can provide experimental basis for the seismic design of curved bridges.

Ways of ensuring the standard of bridge superstructures.

Directory of Open Access Journals (Sweden)

M.G. Malgin

2011-12-01

Full Text Available The structural features of welded railway bridges of the last century were considered. The basic causes of appearance of fatigue cracks in welded joints of railway bridges were assessed. Structural and technological ways of provision of the design life of operated and new-built welded railway bridges are discussed.

Longest cable-stayed bridge TATARA; Longest shachokyo Tatara Ohashi

Energy Technology Data Exchange (ETDEWEB)

Fujii, K. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

1998-06-15

The world`s longest cable-stayed bridge Tatara having a central span of 890 m had the both ends closed in August 1997, linking Namakuchi Island and Omishima Island. Final finishing work is continuing for opening of the West Seto Expressway in the spring of 1999. A cable-stayed bridge supports the bridge girders by perpendicular components of tensile force of cables stayed obliquely. On the other hand, there is a concern that the girders may have axial compression force generated due to horizontal components of the force from the cable tensile force, which can cause buckling of the girders. Therefore, in order to suspend the girders efficiently by increasing the perpendicular components of the cable force, and moreover to suppress the axial compression force on the girders, it is more advantageous to make bridge towers high, hence the towers of this bridge are highest among the bridges on the Shimanami Ocean Road. This bridge whose long girders are stayed with 21-stage multi cables presented a problem in designing the buckling in steel girders near the towers due to the horizontal components of the force generated by the bridge. Discussions were given, therefore, by using load withstanding force experiments using a whole bridge model of 1/50 scale, buckling experiments on full-size reinforcing plate models, and load withstanding force analysis using a tower model. A number of other technical discussions were repeated, by which the world`s longest cable-stayed bridge was completed. 9 figs., 1 tab.

Noise Considerations in Resistance Bridges

DEFF Research Database (Denmark)

Diamond, Joseph M.

1963-01-01

A signal-to-noise analysis is made of the Wheatstone bridge, where the unknown and standard resistors may be at different temperatures, a situation which occurs in resistance thermometry. The limiting condition is assumed to be dissipation in the unknown resistor. It is shown that the ratio arms...... thermometry, where the noise in the unknown resistor will predominate strongly. An impedance step-up device (transformer or tuned circuit) is valuable in raising the bridge signal and noise level above the noise of the first amplifier tube. However, as the step-up ratio is increased, two counterfactors appear....... With certain assumptions about the noise and grid current of the first tube it is found that the equivalent temperature of a unity ratio (Mueller) bridge used for liquid helium measurements may be 400°K....

T-section glulam timber bridge modules : modeling and performance

Science.gov (United States)

Paul A. Morgan; Steven E. Taylor; Michael A. Ritter; John M. Franklin

1999-01-01

This paper describes the design, modeling, and testing of two portable timber bridges, each consisting of two noninterconnected longitudinal glued-laminated timber (glulam) deck panels 1.8 m (6 ft) wide. One bridge is 12.2 m (40 ft) long while the other bridge is 10.7 m (35 ft) long. The deck panels are fabricated in a unique double-tee cross section. The bridges...

Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate

Science.gov (United States)

Iqbal, Muhammad; Ali, Saqib; Tahir, Muhammad Nawaz; Muhammad, Niaz; Shah, Naseer Ali; Sohail, Manzar; Pandarinathan, Vedapriya

2015-08-01

A new binuclear O-bridged Cu(II) complex with 4-chlorophenyl acetate and 2,2‧-bipyridine has been synthesized and characterized using FT-IR, powder and single crystal XRD and electrochemical solution studies. The results revealed that the two penta-coordinated Cu(II) centers are linked by two carboxylate ligands in end-on bonding fashion. The coordination geometry is slightly distorted square pyramidal (SP) with bridging oxygen atoms occupying the apical position and other ligands lying in the equatorial plane. The striking difference in Cu-O bond distance of the bridging oxygen atom in the complex may be responsible for the SP geometry of Cu(II) ion. The complex gave rise to metal centered irreversible electro-activity where one electron Cu(II)/Cu(III) oxidation process and a single step two electron Cu(II)/Cu(0) reduction process was observed. The redox processes were found predominantly adsorption controlled. The values of diffusion coefficient and heterogeneous rate constant for oxidation process were 6.98 × 10-7 cm2 s-1 and 4.60 × 10-5 cm s-1 while the corresponding values for reduction were 5.30 × 10-8 cm2 s-1 and 5.41 × 10-6 cm s-1, respectively. The formal potential and charge transfer coefficient were also calculated. The DNA-binding ability was explored through cyclic voltammetry and UV-Visible spectroscopy. Diminution in the value of Do for oxidation indicated the binding of the complex with DNA corresponding to Kb = 8.58 × 104 M-1. UV-Visible spectroscopy yielded ε = 49 L mol-1 cm-1 and Kb = 2.96 × 104 M-1. The data of both techniques support each other. The self-induced redox activation of the complex, as indicated by cyclic voltammetry heralds its potential applications in redox catalysis and anticancer activity.

23 CFR 650.407 - Application for bridge replacement or rehabilitation.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Application for bridge replacement or rehabilitation... ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.407 Application for bridge replacement or rehabilitation. (a) Agencies participate...

Sensing and Rating of Vehicle–Railroad Bridge Collision

DEFF Research Database (Denmark)

Vemuganti, Shreya; Ozdagli, Ali I.; Liu, Bideng

2017-01-01

Overhead collisions of trucks with low-clearance railway bridges cause more than half of the railway traffic interruptions over bridges in the United States. Railroad owners are required to characterize the damage caused by such events and assess the safety of subsequent train crossings. However...... and remotely quantify damage. This research proposes an impact rating strategy based on the information that best describes the consequences of vehicle-railway bridge collisions. A series of representative impacts were simulated using numerical finite element models of a steel railway bridge. Railway owners...... provided information about the bridge and impact characterization based on railway industry experience. The resulting nonlinear dynamic responses were evaluated with the proposed rating strategy to assess the effect of these impacts. In addition, a neural network methodology was implemented on a simplified...

Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The incised and degraded habitat of Bridge Creek is thought to be limiting a population of ESA-listed steelhead (Oncorhynchus mykiss). A logical restoration approach...

A fiber bridging model for fatigue delamination in composite materials

International Nuclear Information System (INIS)

Gregory, Jeremy R.; Spearing, S. Mark

2004-01-01

A fiber bridging model has been created to examine the effects of bridging on Mode I delamination fatigue fracture in a carbon fiber polymer-matrix composite. The model uses a cohesive zone law that is derived from quasi-static R-curves to determine the bridging energy applied in the bridged region. Timoshenko beam theory and an iterative self-consistent scheme are used to calculate the bridging tractions and displacements. After applying the bridging model to crack propagation data the scatter in the data was significantly reduced and clear trends were observed as a function of temperature that were not apparent previously. This indicated that the model appropriately accounted for the bridging in the experiments. Scanning electron microscopy crack opening displacement measurements were performed to validate the model's predictions. The measurements showed that the predictions were close to the actual bridging levels in the specimen

Magnetic fluid bridge in a non-uniform magnetic field

International Nuclear Information System (INIS)

Pelevina, D.A.; Naletova, V.A.; Turkov, V.A.

2017-01-01

The shape of a magnetic fluid bridge between a horizontal ferrite rod of circular cross-section and a horizontal plate above the rod in a vertical applied uniform magnetic field is studied. Various static shapes of the bridges are obtained theoretically and experimentally for the same magnetic field value. Abrupt changes and the hysteresis of the bridge shape in alternating magnetic fields are observed experimentally. - Highlights: • Magnetic fluid bridge between rod and horizontal plate in magnetic field is studied. • Magnetic field is created by a ferrite rod in a uniform vertical magnetic field. • Various static bridge shapes for fixed field are obtained in theory and experiment. • A good agreement of experimental and theoretical results is obtained. • Hysteresis of the bridge shape in alternating field is observed experimentally.

Magnetic fluid bridge in a non-uniform magnetic field

Energy Technology Data Exchange (ETDEWEB)

Pelevina, D.A., E-mail: pelevina.daria@gmail.com; Naletova, V.A.; Turkov, V.A.

2017-06-01

The shape of a magnetic fluid bridge between a horizontal ferrite rod of circular cross-section and a horizontal plate above the rod in a vertical applied uniform magnetic field is studied. Various static shapes of the bridges are obtained theoretically and experimentally for the same magnetic field value. Abrupt changes and the hysteresis of the bridge shape in alternating magnetic fields are observed experimentally. - Highlights: • Magnetic fluid bridge between rod and horizontal plate in magnetic field is studied. • Magnetic field is created by a ferrite rod in a uniform vertical magnetic field. • Various static bridge shapes for fixed field are obtained in theory and experiment. • A good agreement of experimental and theoretical results is obtained. • Hysteresis of the bridge shape in alternating field is observed experimentally.

Evaluating the life cycle environmental impact of short span bridges

DEFF Research Database (Denmark)

Du, Guangli; Pettersson, Lars; Karoumi, Raid

2016-01-01

impact of the construction sector. Life cycle assessment (LCA) is a systematic method for assessing the environmental impact of products and systems, but its application in bridges is scarce. In Swede, most of the bridges are short spans and the type of concrete slab-frame bridge (CFB) accounts...... for a large share. Soil steel composite bridge (SSCB) is a functional equivalent solution for CFB. In order to mitigate the environmental burdens of short span bridges, this paper performed a comparative LCA study between these two types of bridge. The results indicate that the initial material consumption...

A study on carbon nanotube bridge as a electromechanical memory device

Science.gov (United States)

Kang, Jeong Won; Ha Lee, Jun; Joo Lee, Hoong; Hwang, Ho Jung

2005-04-01

A nanoelectromechanical (NEM) nanotube random access memory (NRAM) device based on carbon nanotube (CNT) was investigated using atomistic simulations. For the CNT-based NEM memory, the mechanical properties of the CNT-bridge and van der Waals interactions between the CNT-bridge and substrate were very important. The critical amplitude of the CNT-bridge was 16% of the length of the CNT-bridge. As molecular dynamics time increased, the CNT-bridge went to the steady state under the electrostatic force with the damping of the potential and the kinetic energies of the CNT-bridge. The interatomic interaction between the CNT-bridge and substrate, value of the CNT-bridge slack, and damping rate of the CNT-bridge were very important for the operation of the NEM memory device as a nonvolatile memory.

The role of bridging organizations in environmental management: examining social networks in working groups

Directory of Open Access Journals (Sweden)

Adam A. Kowalski

2015-06-01

Full Text Available The linkage of diverse sets of actors and knowledge systems across management levels and institutional boundaries often poses one of the greatest challenges in adaptive management of natural resources. Bridging organizations can facilitate interactions among actors in management settings by lowering the transaction costs of collaboration. The Center for Ocean Solutions (COS is an example of a bridging organization that is focused on linking actors within the ocean sciences and governance arena through the use of working groups. This research examines how network connections between group members affect working group functionality and, more specifically, whether cohesive network structures allow groups to more effectively achieve their goals and objectives. A mixed-methods approach, incorporating both qualitative and quantitative data collection and analysis methods, is employed to understand the structural characteristics of COS working groups. The study finds that cohesive network structures are not associated with increased working group functionality. Strong, centralized leadership is a better predictor of working group success in achieving goals and objectives.

BIM authoring for an image-based bridge maintenance system of existing cable-supported bridges

Science.gov (United States)

Dang, N. S.; Shim, C. S.

2018-04-01

Infrastructure nowadays is increasingly become the main backbone for the metropolitan development in general. Along with the rise of new facilities, the demand in term of maintenance for the existing bridges is indispensable. Recently, the terminology of “preventive maintenance” is not unfamiliar with the engineer, literally is the use of a bridge maintenance system (BMS) based on a BIM-oriented model. In this paper, the process of generating a BMS based on BIM model is introduced in detail. Data management for this BMS is separated into two modules: site inspection system and information management system. The noteworthy aspect of this model lays on the closed and automatic process of “capture image, generate the technical damage report, and upload/feedback to the BMS” in real-time. A pilot BMS system for a cable-supported bridge is presented which showed a good performance and potential to further development of preventive maintenance.

Myocardial bridges of the coronary arteries in the human fetal heart.

Science.gov (United States)

Cakmak, Yusuf Ozgür; Cavdar, Safiye; Yalin, Aymelek; Yener, Nuran; Ozdogmus, Omer

2010-09-01

During the last century, many investigators reported on myocardial bridges in the adult human heart. In the present study, 39 human fetal hearts (the mean gestastional age was 30 weeks) were studied for myocardial bridging, and the results were correlated with adult data. Among the 39 (27 male and 12 female) fetal hearts studied, 26 bridges were observed on 18 fetal hearts (46.2%). Ten of the bridges had one myocardial bridge, whereas double myocardial bridges were observed in eight fetal hearts. The most frequent myocardial bridges were observed on the left anterior descending artery (LAD), which had 13 bridges (50%). Eight (30.7%) myocardial bridges were on the diagonal artery, and on the posterior descending artery there were five (19.3%). Myocardial bridges were not observed on the circumflex artery. The data presented in this study may provide potentially useful information for the preoperative evaluation of the newborn and may have a clinical implication for sudden fetal death.

Overview of the National Timber Bridge Inspection Study

Science.gov (United States)

James P. Wacker; Brian K. Brashaw; Frank Jalinoos

2013-01-01

As many engineers begin to implement life cycle cost analyses within the preliminary bridge design phase, there is a significant need for more reliable data on the expected service life of highway bridges. Many claims are being made about the expected longevity of concrete and steel bridges, but few are based on actual performance data. Because engineers are least...

Collapse of the Tacoma· N arrows Bridge

Indian Academy of Sciences (India)

something was noticeably wrong with the bridge. The span ... So spectacular was the motion at times that the bridge was soon nicknamed Galloping. Gertie, and visitors ... A stranded car can be seen on the top right corner. ... home from Cal Tech a small rubber model of the bridge which one of my mechanics had made for ...

An expert system for the esthetic rating of bridges.

Science.gov (United States)

1990-01-01

The expert system presented should facilitate the in-depth analysis of bridge esthetics and encourage high standards for the appearance of bridges. The procedure described systematically evaluates features of a target bridge in relation to a similar ...

Implementation of sustainability in bridge design, construction and maintenance.

Science.gov (United States)

2012-12-01

The focus of this research is to develop a framework for more sustainable design and construction : processes for new bridges, and sustainable maintenance practices for existing bridges. The framework : includes a green rating system for bridges. The...

“On a bridge in Berlin”

DEFF Research Database (Denmark)

Pihl, Ole Verner

2013-01-01

This is a self-reflective case study based on the development of the Graphic Novel: “On a bridge in Berlin.” The GN will be used as an introduction to the history of architecture as a part of the curriculum in Architecture and Design at Aalborg University, and as a more broadly introduction...... that jumps in time and place: it begins with Martin Heidegger´s quotation “The Bridge gathers to itself in its own way earth and sky, divinities and mortals”, and the bridge is a state of mind, a chronotope, a portal in time between past, present, and future. The methodological approach is based...

Noise measurements on proximity effect bridges

International Nuclear Information System (INIS)

Decker, S.K.; Mercereau, J.E.

1975-01-01

Audio frequency noise density measurements were performed on weakly superconducting proximity effect bridges on using a cooled transformer and room temperature low noise preamplifier. The noise temperature of the measuring system is approximately 4 0 K for a 0.9 Ω resistor. Noise density was measured as a function of bias current and temperature for the bridges. Excess noise above that expected from Johnson noise for a resistor equal to the dynamic resistance of the bridges was observed in the region near the critical current of the device. At high currents compared to the critical current, the noise density closely approaches that given by Johnson noise

Heavy Vehicles on Minor Highway Bridges

DEFF Research Database (Denmark)

Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

of heavier trucks moving at larger speeds, and partly because the authorities want to permit transportation of special heavy goods at a larger part of the road net. These needs will in many cases cause the strengthening of the bridges becomes necessary. In order to keep the expenses of such strengthening...... the results obtained using the numerical models given in details in "Heavy Vehicles on Minor Highway Bridges : dynamic modelling of vehicles and bridges". The models are established using a ordinary vehicle which consists of a 48 t Scania with a 3 axle tractor and a 3 axle trailer, joined in a flexible hinge...

Super-bridges suspended over carbon nanotube cables

Science.gov (United States)

Carpinteri, Alberto; Pugno, Nicola M.

2008-11-01

In this paper the new concept of 'super-bridges', i.e. kilometre-long bridges suspended over carbon nanotube cables, is introduced. The analysis shows that the use of realistic (thus defective) carbon nanotube bundles as suspension cables can enlarge the current limit main span by a factor of ~3. Too large compliance and dynamic self-excited resonances could be avoided by additional strands, rendering the super-bridge anchored as a spider's cobweb. As an example, we have computed the limit main spans of the current existing 19 suspended-deck bridges longer than 1 km assuming them to have substituted their cables with carbon nanotube bundles (thus maintaining the same geometry, with the exception of the length) finding spans of up to ~6.3 km. We thus suggest that the design of the Messina bridge in Italy, which would require a main span of ~3.3 km, could benefit from the use of carbon nanotube bundles. We believe that their use represents a feasible and economically convenient solution. The plausibility of these affirmations is confirmed by a statistical analysis of the existing 100 longest suspended bridges, which follow a Zipf's law with an exponent of 1.1615: we have found a Moore-like (i.e. exponential) law, in which the doubling of the capacity (here the main span) per year is substituted by the factor 1.0138. Such a law predicts that the realization of the Messina bridge using conventional materials will only occur around the middle of the present century, whereas it could be expected in the near future if carbon nanotube bundles were used. A simple cost analysis concludes the paper.

Super-bridges suspended over carbon nanotube cables

International Nuclear Information System (INIS)

Carpinteri, Alberto; Pugno, Nicola M

2008-01-01

In this paper the new concept of 'super-bridges', i.e. kilometre-long bridges suspended over carbon nanotube cables, is introduced. The analysis shows that the use of realistic (thus defective) carbon nanotube bundles as suspension cables can enlarge the current limit main span by a factor of ∼3. Too large compliance and dynamic self-excited resonances could be avoided by additional strands, rendering the super-bridge anchored as a spider's cobweb. As an example, we have computed the limit main spans of the current existing 19 suspended-deck bridges longer than 1 km assuming them to have substituted their cables with carbon nanotube bundles (thus maintaining the same geometry, with the exception of the length) finding spans of up to ∼6.3 km. We thus suggest that the design of the Messina bridge in Italy, which would require a main span of ∼3.3 km, could benefit from the use of carbon nanotube bundles. We believe that their use represents a feasible and economically convenient solution. The plausibility of these affirmations is confirmed by a statistical analysis of the existing 100 longest suspended bridges, which follow a Zipf's law with an exponent of 1.1615: we have found a Moore-like (i.e. exponential) law, in which the doubling of the capacity (here the main span) per year is substituted by the factor 1.0138. Such a law predicts that the realization of the Messina bridge using conventional materials will only occur around the middle of the present century, whereas it could be expected in the near future if carbon nanotube bundles were used. A simple cost analysis concludes the paper.

Long-term behavior of integral abutment bridges : [technical summary].

Science.gov (United States)

2011-01-01

Integral abutment bridges, a type of jointless bridge, are the construction option of choice when designing highway bridges in many parts of the country. Rather than providing an expansion joint to separate the substructure from the superstructure to...

Simple model of cable-stayed bridge deck subjected to static wind loading

Science.gov (United States)

Kang, Yi-Lung; Wang, Yang Cheng

1997-05-01

Cable-stayed bridges have been known since 18th century with aesthetics design. The structural system and the structural behavior are significantly different from those of continuous bridges. Compared to continuous bridge, cable- stayed bridges have more flexure bridge deck than those of continuous bridges.On the other hand, cable-stayed bridges have less stiffness to resist wind loading especially for lateral loads. The first considering of bridge engineering is safety. In 1940's, Tacoma Narrows Suspension Bridge destroyed by wind loading is a good example even though it is not a cable-stayed bridge. After the bridge was destroyed, a lot of research articles have been published regarding cable supported bridge subjected to wind loading. In recent days, high strength materials have been served. The bridge engineers use the advantages to expand the span length of cable-stayed bridges. Due to the span length increased and the use of high strength materials, cable- stayed bridges have more significant nonlinear behavior subjected to wind loading. In this paper, a slice bridge deck of cable-stayed bridge connected to internal support cables is considered. The deck has been considered to be subjected to lateral static wind loading. Since cables can not take compressive force, the deck has strongly nonlinear behavior even though the materials are linear elastic. Several primary load combinations have ben considered in this paper such as the bridge deck supposed to be moved horizontally without rotation or the bridge deck supposed to be moved horizontally with rotational deformation. The mathematical formulas and the numerical solutions are found and represented in graphical forms. The results can be provided to bridge designers and researchers for further study of this type of structure subjected to wind loading.

Monitoring Bridge Dynamic Deformation in Vibration by Digital Photography

Science.gov (United States)

Yu, Chengxin; Zhang, Guojian; Liu, Xiaodong; Fan, Li; Hai, Hua

2018-01-01

This study adopts digital photography to monitor bridge dynamic deformation in vibration. Digital photography in this study is based on PST-TBPM (photographing scale transformation-time baseline parallax method). Firstly, we monitor the bridge in static as a zero image. Then, we continuously monitor the bridge in vibration as the successive images. Based on the reference points on each image, PST-TBPM is used to calculate the images to obtain the dynamic deformation values of these deformation points. Results show that the average measurement accuracies are 0.685 pixels (0.51mm) and 0.635 pixels (0.47mm) in X and Z direction, respectively. The maximal deformations in X and Z direction of the bridge are 4.53 pixels and 5.21 pixels, respectively. PST-TBPM is valid in solving the problem that the photographing direction is not perpendicular to the bridge. Digital photography in this study can be used to assess bridge health through monitoring the dynamic deformation of a bridge in vibration. The deformation trend curves also can warn the possible dangers over time.

33 CFR 115.30 - Sufficiency of State authority for bridges.

Science.gov (United States)

2010-07-01

... for bridges. 115.30 Section 115.30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.30 Sufficiency of State authority for bridges. An opinion of the attorney general of the State as to the sufficiency of State...

Application of Artificial Intelligence for Bridge Deterioration Model

Directory of Open Access Journals (Sweden)

Zhang Chen

2015-01-01

Full Text Available The deterministic bridge deterioration model updating problem is well established in bridge management, while the traditional methods and approaches for this problem require manual intervention. An artificial-intelligence-based approach was presented to self-updated parameters of the bridge deterioration model in this paper. When new information and data are collected, a posterior distribution was constructed to describe the integrated result of historical information and the new gained information according to Bayesian theorem, which was used to update model parameters. This AI-based approach is applied to the case of updating parameters of bridge deterioration model, which is the data collected from bridges of 12 districts in Shanghai from 2004 to 2013, and the results showed that it is an accurate, effective, and satisfactory approach to deal with the problem of the parameter updating without manual intervention.

Bridge Management Strategy Based on Extreme User Costs for Bridge Network Condition

Directory of Open Access Journals (Sweden)

Ladislaus Lwambuka

2014-01-01

Full Text Available This paper presents a practical approach for prioritization of bridge maintenance within a given bridge network. The maintenance prioritization is formulated as a multiobjective optimization problem where the simultaneous satisfaction of several conflicting objectives includes minimization of maintenance costs, maximization of bridge deck condition, and minimization of traffic disruption and associated user costs. The prevalence of user cost during maintenance period is twofold; the first case refers to the period of dry season where normally the traffic flow is diverted to alternative routes usually resurfaced to regain traffic access. The second prevalence refers to the absence of alternative routes which is often the case in the least developed countries; in this case the user cost referred to results from the waiting time while the traffic flow is put on hold awaiting accomplishment of the maintenance activity. This paper deals with the second scenario of traffic closure in the absence of alternative diversion routes which in essence results in extreme user cost. The paper shows that the multiobjective optimization approach remains valid for extreme cases of user costs in the absence of detour roads as often is the scenario in countries with extreme poor road infrastructure.

Guardrails for Use on Historic Bridges: Volume 1—Replacement Strategies

OpenAIRE

Frosch, Robert J.; Kreger, Michael E.; Clauss, Adam J.

2016-01-01

Bridges that are designated historic present a special challenge to bridge engineers whenever rehabilitation work or improvements are made to the bridges. Federal and state laws protect historically significant bridges, and railings on these bridges can be subject to protection because of the role they play in aesthetics. Unfortunately, original railings on historic bridges do not typically meet current crash-test requirements and typically do not meet current standards for railing height and...

Exploring the relevance of thiophene rings as bridge unit in acceptor-bridge-donor dyes on self-aggregation and performance in DSSCs.

Science.gov (United States)

Zarate, Ximena; Saavedra-Torres, Mario; Rodriguez-Serrano, Angela; Gomez, Tatiana; Schott, Eduardo

2018-04-30

The possibility of dye charge recombination in DSSCs remains a challenge for the field. This consists of: (a) back-transfer from the TiO 2 to the oxidized dye and (b) intermolecular electron transfer between dyes. The latter is attributed to dye aggregation due to dimeric conformations. This leads to poor electron injection which decreases the photocurrent conversion efficiency. Most organic sensitizers are characterized by an Acceptor-Bridge-Donor (A-Bridge-D) arrangement that is commonly employed to provide charge separation and, therefore, lowering the unwanted back-transfer. Here, we address the intermolecular electron transfer by studying the dimerization and photovoltaic performance of a group of A-Bridge-D structured dyes. Specifically, eight famous sulfur containing π-bridges were analyzed (A and D remained fixed). Through quantum mechanical and molecular dynamics approaches, it was found that the formation of weakly stabilized dimers is allowed. The dyes with covalently bonded and fused thiophene rings as Bridges, 6d and 7d as well as 8d with a fluorene, would present high aggregation and, therefore, high probability of recombination processes. Conversely, using TiO 2 cluster and surface models, delineated the shortest bridges to improve the adsorption energy and the stability of the system. Finally, the elongation of the bridge up to 2 and 3 units and their photovoltaic parameters were studied. These results showed that all the sensitizers are able to provide similar photocurrent outcomes, regardless of whether the bridge is elongated. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Verification of LRFD Bridge Design and Analysis Software for INDOT

OpenAIRE

Varma, Amit H.; Seo, Jungil

2009-01-01

NCHRP Process 12-50 was implemented to evaluate and verify composite steel I-girder bridge design software used commonly in Indiana. A test-bed of twenty one bridges was developed with the guidance from an Indiana Department of Transportation appointed research advisory panel (RAP). The test-bed included five simple-span and sixteen multi-span bridge superstructures. More than 80 parameters were required to define a bridge and they include bridge span, girder spacing, number of beams, section...

Expected damages of retrofitted bridges with RC jacketing

Science.gov (United States)

Montes, O.; Jara, J. M.; Jara, M.; Olmos, B. A.

2015-07-01

The bridge infrastructure in many countries of the world consists of medium span length structures built several decades ago and designed for very low seismic forces. Many of them are reinforced concrete structures that according to the current code regulations have to be rehabilitated to increase their seismic capacity. One way to reduce the vulnerability of the bridges is by using retrofitting techniques that increase the strength of the structure or by incorporating devices to reduce the seismic demand. One of the most common retrofit techniques of the bridges substructures is the use of RC jacketing; this research assesses the expected damages of seismically deficient medium length highway bridges retrofitted with reinforced concrete jacketing, by conducting a parametric study. We select a suite of twenty accelerograms of subduction earthquakes recorded close to the Pacific Coast in Mexico. The original structures consist of five 30 m span simple supported bridges with five pier heights of 5 m, 10 m, 15 m 20 and 25 m and the analyses include three different jacket thickness and three steel ratios. The bridges were subjected to the seismic records and non-linear time history analyses were carried out by using the OpenSEEs Plataform. Results allow selecting the reinforced concrete jacketing that better improves the expected seismic behavior of the bridge models.

Expected damages of retrofitted bridges with RC jacketing

International Nuclear Information System (INIS)

Montes, O; Jara, J M; Jara, M; Olmos, B A

2015-01-01

The bridge infrastructure in many countries of the world consists of medium span length structures built several decades ago and designed for very low seismic forces. Many of them are reinforced concrete structures that according to the current code regulations have to be rehabilitated to increase their seismic capacity. One way to reduce the vulnerability of the bridges is by using retrofitting techniques that increase the strength of the structure or by incorporating devices to reduce the seismic demand. One of the most common retrofit techniques of the bridges substructures is the use of RC jacketing; this research assesses the expected damages of seismically deficient medium length highway bridges retrofitted with reinforced concrete jacketing, by conducting a parametric study. We select a suite of twenty accelerograms of subduction earthquakes recorded close to the Pacific Coast in Mexico. The original structures consist of five 30 m span simple supported bridges with five pier heights of 5 m, 10 m, 15 m 20 and 25 m and the analyses include three different jacket thickness and three steel ratios. The bridges were subjected to the seismic records and non-linear time history analyses were carried out by using the OpenSEEs Plataform. Results allow selecting the reinforced concrete jacketing that better improves the expected seismic behavior of the bridge models. (paper)

Improved Simplified Methods for Effective Seismic Analysis and Design of Isolated and Damped Bridges in Western and Eastern North America

Science.gov (United States)

Koval, Viacheslav

The seismic design provisions of the CSA-S6 Canadian Highway Bridge Design Code and the AASHTO LRFD Seismic Bridge Design Specifications have been developed primarily based on historical earthquake events that have occurred along the west coast of North America. For the design of seismic isolation systems, these codes include simplified analysis and design methods. The appropriateness and range of application of these methods are investigated through extensive parametric nonlinear time history analyses in this thesis. It was found that there is a need to adjust existing design guidelines to better capture the expected nonlinear response of isolated bridges. For isolated bridges located in eastern North America, new damping coefficients are proposed. The applicability limits of the code-based simplified methods have been redefined to ensure that the modified method will lead to conservative results and that a wider range of seismically isolated bridges can be covered by this method. The possibility of further improving current simplified code methods was also examined. By transforming the quantity of allocated energy into a displacement contribution, an idealized analytical solution is proposed as a new simplified design method. This method realistically reflects the effects of ground-motion and system design parameters, including the effects of a drifted oscillation center. The proposed method is therefore more appropriate than current existing simplified methods and can be applicable to isolation systems exhibiting a wider range of properties. A multi-level-hazard performance matrix has been adopted by different seismic provisions worldwide and will be incorporated into the new edition of the Canadian CSA-S6-14 Bridge Design code. However, the combined effect and optimal use of isolation and supplemental damping devices in bridges have not been fully exploited yet to achieve enhanced performance under different levels of seismic hazard. A novel Dual-Level Seismic

Pilot testing of a hydraulic bridge exciter

Directory of Open Access Journals (Sweden)

Andersson Andreas

2015-01-01

Full Text Available This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally determine frequency response functions at all sensor locations, which serve as valuable input for model updating and verification. An FE-model of the case study bridge has been developed that is in good agreement with the experimental results.

Post-Earthquake Traffic Capacity of Modern Bridges in California

Science.gov (United States)

2010-03-01

Evaluation of the capacity of a bridge to carry self-weight and traffic loads after an earthquake is essential for a : safe and timely re-opening of the bridge. In California, modern highway bridges designed using the Caltrans : Seismic Design Criter...

Detection of salt bridges to lysines in solution in barnase

DEFF Research Database (Denmark)

Hansen, Poul Erik; Williamson, Michael P.; Hounslow, Andrea M.

2013-01-01

We show that salt bridges involving lysines can be detected by deuterium isotope effects on NMR chemical shifts of the sidechain amine. Lys27 in the ribonuclease barnase is salt bridged, and mutation of Arg69 to Lys retains a partially buried salt bridge. The salt bridges are functionally important....

Exploring Bridge-Engine Control Room Collaborative Team Communication

Directory of Open Access Journals (Sweden)

Aditi Kataria

2015-06-01

Full Text Available The EC funded CyClaDes research project is designed to promote the increased impact of the human element in shipping across the design and operational lifecycle. It addresses the design and operation of ships and ship systems. One of the CyClaDes’ tasks is to create a crew-centered design case-study examination of the information that is shared between the Bridge and Engine Control Room that helps the crew co-ordinate to ensure understanding and complete interconnected tasks. This information can be provided in various ways, including communication devices or obtained from a common database, display, or even the ship environment (e.g., the roll of the ship. A series of semi-structured interviews were conducted with seafarers of diverse ranks to get a better idea of what communication does, or should, take place and any problems or challenges existing in current operations, as seen from both the bridge and ECR operators’ perspectives. Included in the interview were both the standard communications and information shared during planning and executing a voyage, as well as special situations such as safety/casualty tasks or heavy weather. The results were analyzed in terms of the goals of the communication, the primary situations of interest for communication and collaboration, the communication media used, the information that is shared, and the problems experienced. The results of seafarer interviews are presented in the paper to explore on-board inter-departmental communication.

Fabrication of ultrashort niobium variable-thickness bridges

International Nuclear Information System (INIS)

Goto, T.

1982-01-01

A simple technique for the fabrication of niobium variable-thickness bridges of length approx.0.1 μm is described. The bridges are found to operate as ideal Josephson junctions over a wide temperature range

Bridging the Gap (BRIEFING CHARTS)

Science.gov (United States)

2007-03-05

1 Defense Advanced Research Projects Agency “Bridging the Gap ” Dr. Robert F. Leheny Deputy Director Report Documentation Page Form ApprovedOMB No...comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to...4. TITLE AND SUBTITLE Bridging the Gap 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

Multi-Hazard Assessment of Scour Damaged Bridges with UAS-Based Measurements

Science.gov (United States)

Özcan, O.; Ozcan, O.

2017-12-01

Flood and stream induced scour occurring in bridge piers constructed on rivers is one of the mostly observed failure reasons in bridges. Scour induced failure risk in bridges and determination of the alterations in bridge safety under seismic effects has the ultimate importance. Thus, for the determination of bridge safety under the scour effects, the scour amount under bridge piers should be designated realistically and should be tracked and updated continuously. Hereby, the scour induced failures in bridge foundation systems will be prevented and bridge substructure design will be conducted safely. In this study, in order to measure the amount of scour in bridge load bearing system (pile foundations and pile abutments) and to attain very high definition 3 dimensional models of river flood plain for the flood analysis, unmanned aircraft system (UAS) based measurement methods were implemented. UAS based measurement systems provide new and practical approach and bring high precision and reliable solutions considering recent measurement systems. For this purpose, the reinforced concrete (RC) bridge that is located on Antalya Boğaçayı River, Turkey and that failed in 2003 due to flood-induced scour was selected as the case study. The amount of scour occurred in bridge piers and piles was determined realistically and the behavior of bridge piers under scour effects was investigated. Future flood effects and the resultant amount of scour was determined with HEC-RAS software by using digital surface models that were obtained at regular intervals using UAS for the riverbed. In the light of the attained scour measurements and expected scour after a probable flood event, the behavior of scour damaged RC bridge was investigated by pushover and time history analyses under lateral and vertical seismic loadings. In the analyses, the load and displacement capacity of bridge was observed to diminish significantly under expected scour. Thus, the deterioration in multi hazard

Development of a numerical model for vehicle-bridge interaction analysis of railway bridges

Science.gov (United States)

Kim, Hee Ju; Cho, Eun Sang; Ham, Jun Su; Park, Ki Tae; Kim, Tae Heon

2016-04-01

In the field of civil engineering, analyzing dynamic response was main concern for a long time. These analysis methods can be divided into moving load analysis method and moving mass analysis method, and formulating each an equation of motion has recently been studied after dividing vehicles and bridges. In this study, the numerical method is presented, which can consider the various train types and can solve the equations of motion for a vehicle-bridge interaction analysis by non-iteration procedure through formulating the coupled equations for motion. Also, 3 dimensional accurate numerical models was developed by KTX-vehicle in order to analyze dynamic response characteristics. The equations of motion for the conventional trains are derived, and the numerical models of the conventional trains are idealized by a set of linear springs and dashpots with 18 degrees of freedom. The bridge models are simplified by the 3 dimensional space frame element which is based on the Euler-Bernoulli theory. The rail irregularities of vertical and lateral directions are generated by PSD functions of the Federal Railroad Administration (FRA).

Guide for In-Place Treatment of Covered and Timber Bridges

Science.gov (United States)

Stan Lebow; Grant Kirker; Robert White; Terry Amburgey; H. Michael Barnes; Michael Sanders; Jeff Morrell

2012-01-01

Historic covered bridges and current timber bridges can be vulnerable to damage from biodeterioration or fire. This guide describes procedures for selecting and applying in-place treatments to prevent or arrest these forms of degradation. Vulnerable areas for biodeterioration in covered bridges include members contacting abutments, members near the ends of bridges...

Risk Mitigation for Highway and Railway Bridges

Science.gov (United States)

2009-02-01

Performance of the transportation network strongly depends on the performance of bridges. Bridges constitute a vital part of the transportation infrastructure system and they are vulnerable to extreme events such as natural disasters (i.e., hurricane...

Development and validation of deterioration models for concrete bridge decks - phase 1 : artificial intelligence models and bridge management system.

Science.gov (United States)

2013-06-01

This research documents the development and evaluation of artificial neural network (ANN) models to predict the condition ratings of concrete highway bridge decks in Michigan. Historical condition assessments chronicled in the national bridge invento...

Bridge Condition Assessment based on Vibration Responses of Passenger Vehicle

International Nuclear Information System (INIS)

Miyamoto, Ayaho; Yabe, Akito

2011-01-01

In this paper, we propose a new method of assessing the condition of existing short- and medium-span reinforced/prestressed concrete bridges based on vibration monitoring data obtained from a public bus. This paper not only describes details of a prototype monitoring system that uses information technology and sensors capable of providing more accurate knowledge of bridge performance than conventional ways but also shows a few specific examples of bridge condition assessment based on vehicle vibrations measured by using an in-service public bus equipped with vibration measurement instrumentation. This paper also describes a sensitivity analysis of deteriorating bridges based on simulation of the acceleration response of buses conducted by the 'substructure method' employing a finite element model to verify the above bridge performance results. The main conclusions obtained in this study can be summarized as follows: (1) Because the vibration responses of passenger vehicles, such as buses, have a good linear relationship with the vibration responses of the target bridges, the proposed system can be used as a practical monitoring system for bridge condition assessment. (2) The results of sensitivity analysis performed by the substructure method show that bus vibration responses are useful for evaluating target bridge performance. (3) The proposed method was applied to a network of real bridges in a local area to evaluate its effectiveness. The results indicate that the proposed method can be used to prioritize the repair/strengthening works of existing bridges based on various vibration information in order to help bridge administrators establish rational maintenance strategies.

Bridge scour countermeasure assessments at select bridges in the United States, 2014–16

Science.gov (United States)

Dudunake, Taylor J.; Huizinga, Richard J.; Fosness, Ryan L.

2017-05-23

In 2009, the Federal Highway Administration published Hydraulic Engineering Circular No. 23 (HEC-23) to provide specific design and implementation guidelines for bridge scour and stream instability countermeasures. However, the effectiveness of countermeasures implemented over the past decade following those guidelines has not been evaluated. Therefore, in 2013, the U.S. Geological Survey, in cooperation with the Federal Highway Administration, began a study to assess the current condition of bridge-scour countermeasures at selected sites to evaluate their effectiveness. Bridge-scour countermeasures were assessed during 2014-2016. Site assessments included reviewing countermeasure design plans, summarizing the peak and daily streamflow history, and assessments at each site. Each site survey included a photo log summary, field form, and topographic and bathymetric geospatial data and metadata. This report documents the study area and site-selection criteria, explains the survey methods used to evaluate the condition of countermeasures, and presents the complete documentation for each countermeasure assessment.

Study of special spacer with damping device for suppressing wake galloping in tandem cables of cable-stayed bridges and its application to full scale bridge; Nendanseitai wo riyoshita heiretsu cable yo gensui kinotsuki spacer to sono jikkyo cable eno tekiyo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Yoneda, M.; Setouchi, H.; Yoshioka, A. [Kawada Industries Inc., Tokyo (Japan); Shimoda, I.; Kawahara, S. [Oiles Corp., Tokyo (Japan)

1996-12-20

Cable vibration called wake galloping occurs in a cable-stayed bridge, in which cables are arranged tandem, and suppression of the vibration is an extremely important discussion item. This paper describes a complex eigen value analysis performed on tandem cables having lengths of 200 m and 100 m. The analysis revealed that damping characteristics added by a spacer system with a damping device (a type to install a visco-elastic body at about middle of the tandem cables via a jig) depend largely on torsional rigidity of the cables; and the characteristics may vary with difference in intervals between cable centers and that in cable diameters. A visco-elastic damping material of an asphalt system and a spacer with a damping device used as a spring material were fabricated and applied to a full scale bridge to identify quantitatively the damping addition characteristics of this system. Furthermore, the results of tests on the full scale bridge were compared with the result of the complex eigen value analysis, from which findings useful for actual works were obtained. 18 refs., 17 figs., 6 tabs.

Reserves in load capacity assessment of existing bridges

Science.gov (United States)

Žitný, Jan; Ryjáček, Pavel

2017-09-01

High percentage of all railway bridges in the Czech Republic is made of structural steel. Majority of these bridges is designed according to historical codes and according to the deterioration, they have to be assessed if they satisfy the needs of modern railway traffic. The load capacity assessment of existing bridges according to Eurocodes is however often too conservative and especially, braking and acceleration forces cause huge problems to structural elements of the bridge superstructure. The aim of this paper is to review the different approaches for the determination of braking and acceleration forces. Both, current and historical theoretical models and in-situ measurements are considered. The research of several local European state norms superior to Eurocode for assessment of existing railway bridges shows the big diversity of used local approaches and the conservativeness of Eurocode. This paper should also work as an overview for designers dealing with load capacity assessment, revealing the reserves for existing bridges. Based on these different approaches, theoretical models and data obtained from the measurements, the method for determination of braking and acceleration forces on the basis of real traffic data should be proposed.

Square function analysis of the Inductor-Converter Bridge

International Nuclear Information System (INIS)

Ehsani, M.; Kustom, R.L.

1979-03-01

The transfer of energy between two superconducting coils can be controlled with an Inductor-Converter Bridge (ICB) by changing the relative timing between the storage side bridge and the load side bridge. The average voltages on the coils have been previously derived as a function of relative timing between the two halves of the bridges and the relative currents in the two coils using a one-line, harmonic current source representation of each coil and its bridge network. Since the coil current in each of the ICB phases appears as bipolar rectangular pulses, an analysis based on unit step functions has been developed. The unit step function analysis leads to simple polynomial expressions relating the average coil voltages to relative timing. The new derivations are shown to have the same harmonic representation as previously developed. The polynomial expressions are more compatible to microprocessor control than are the harmonic function expressions

Design and construction of the Natorigawa Bridge; Natorigawa kyoryo no sekkei/seko

Energy Technology Data Exchange (ETDEWEB)

Murai, Y.; Oba, M.; Omurata, Y. [JR East Japan Railway Co., Tokyo (Japan); Miyauchi, M.; Iwasaki, I. [Taisei Corp., Tokyo (Japan)

1997-03-31

The Natorigawa Bridge is reconstructed. Out of the reconstruction work, a report is made mainly on the design of the superstructure work of the PC panel-stayed bridge and the details of the work. In selecting bridge type, PC simple through beam bridge, steel trussed bridge, PC cable-stayed bridge, and PC panel-stayed bridge are compared, and a 2-span continuous PC panel-stayed bridge is adopted. Its appearance resembles that of the cable-stayed bridge, but the structure resembles a girder bridge. The appropriate span length is the intermediate range between those of the girder bridge and the cable-stayed bridge. Its trafficability is excellent with little deformation by the running of trains because the main beam, diagonal panel, and the main tower are connected rigidly to provide high rigidity of the entire bridge. PRC structure is employed in consideration of the restriction to beam height and economical efficiency. Analyses by a FEM model using two dimensional plane elements and by a few plane frame models as well as comparison of sectional force are performed for this bridge, and a proper plane model is selected. Substructure work, superstructure work and measurement work are described. 3 refs., 16 figs., 6 tabs.

Structural condition assessment of the bridge in Ostrava

Directory of Open Access Journals (Sweden)

Čech Jindřich

2017-01-01

Full Text Available This paper deals with the comparison of results of dynamic test and numerical modelling of a road bridge across the Dr. Kudela street in the street Rudná in Ostrava. The bridge is a reinforced concrete structure, made of post-tensioned KA-beams. On the bridge were verified material properties. Calculation model to validate the static and dynamic behavior of structures was created. On the bridge were measured dynamic properties (frequency, mode shapes and attenuation during excitation construction by hydraulic vibration exciter. Article will focus on comparing the results of the calculation of dynamic structures and properties measured on real structure upon excitation.

Analytical investigation of bidirectional ductile diaphragms in multi-span bridges

Science.gov (United States)

Wei, Xiaone; Bruneau, Michel

2018-04-01

In the AASHTO Guide Specifications for Seismic Bridge Design Provisions, ductile diaphragms are identified as Permissible Earthquake-Resisting Elements (EREs), designed to help resist seismic loads applied in the transverse direction of bridges. When adding longitudinal ductile diaphragms, a bidirectional ductile diaphragm system is created that can address seismic excitations acting along both the bridge's longitudinal and transverse axes. This paper investigates bidirectional ductile diaphragms with Buckling Restrained Braces (BRBs) in straight multi-span bridge with simply supported floating spans. The flexibility of the substructures in the transverse and longitudinal direction of the bridge is considered. Design procedures for the bidirectional ductile diaphragms are first proposed. An analytical model of the example bridge with bidirectional ductile diaphragms, designed based on the proposed methodology, is then built in SAP2000. Pushover and nonlinear time history analyses are performed on the bridge model, and corresponding results are presented. The effect of changing the longitudinal stiffness of the bidirectional ductile diaphragms in the end spans connecting to the abutment is also investigated, in order to better understand the impact on the bridge's dynamic performance.

Geometry dependence of the magnetization reversal process in bridged dots

International Nuclear Information System (INIS)

Escobar, R.A.; Lage, E.; D’Albuquerque e Castro, J.; Altbir, D.; Ross, C.A.

2017-01-01

Based on Monte Carlo numerical simulations: results for the magnetization reversal process in thin circular Ni dots connected by a bridge are presented. The dependence of the process on both the width of the bridge and the orientation of the applied magnetic field has been investigated. It was found that when the applied magnetic field is set parallel to the bridge, the hysteresis curves are weakly dependent on the width of the bridge, being rather close to that of a single dot of the same diameter. On the other hand, when the magnetic field is applied perpendicularly to the bridge, a significant reduction in the coercivity of the system is obtained, even in the case of narrower bridges.

Geometry dependence of the magnetization reversal process in bridged dots

Energy Technology Data Exchange (ETDEWEB)

Escobar, R.A. [Departamento de Física, CEDENNA, Universidad de Santiago de Chile, USACH, Av. Ecuador 3493, Santiago (Chile); Lage, E. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 02139 Cambridge, MA (United States); D’Albuquerque e Castro, J. [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21945-970 (Brazil); Altbir, D., E-mail: dora.altbir@usach.cl [Departamento de Física, CEDENNA, Universidad de Santiago de Chile, USACH, Av. Ecuador 3493, Santiago (Chile); Ross, C.A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 02139 Cambridge, MA (United States)

2017-06-15

Based on Monte Carlo numerical simulations: results for the magnetization reversal process in thin circular Ni dots connected by a bridge are presented. The dependence of the process on both the width of the bridge and the orientation of the applied magnetic field has been investigated. It was found that when the applied magnetic field is set parallel to the bridge, the hysteresis curves are weakly dependent on the width of the bridge, being rather close to that of a single dot of the same diameter. On the other hand, when the magnetic field is applied perpendicularly to the bridge, a significant reduction in the coercivity of the system is obtained, even in the case of narrower bridges.

Renovation techniques for fatigue cracked orthotropic steel bridge decks

NARCIS (Netherlands)

de Jong, F.B.P.

2007-01-01

This dissertation presents the research into renovation techniques for orthotropic steel bridge decks. These techniques are needed to solve fatigue problems in the decks of these bridges, as several fatigue cracks have been detected in the deck structure of these bridges the last decade. A

PARAMETRIC STUDY OF SKEW ANGLE ON BOX GIRDER BRIDGE DECK

OpenAIRE

Shrikant D. Bobade *, Dr. Valsson Varghese

2016-01-01

Box girder bridge deck, is the most common type of bridges in world and India, it consists of several Slab or girders. The span in the direction of the roadway and connected across their tops and bottoms by a thin continuous structural stab, the longitudinal box girders can be made of steel or concrete. The Simple supported single span concrete bridge deck is presented in present study. Skewed bridges are suitable in highway design when the geometry of straight bridges is not possible. The sk...

33 CFR 401.52 - Limit of approach to a bridge.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Limit of approach to a bridge... approach to a bridge. (a) No vessel shall pass the limit of approach sign at any movable bridge until the bridge is in a fully open position and the signal light shows green. (b) No vessel shall pass the limit...

Active Control of Long Bridges Using Flaps

DEFF Research Database (Denmark)

Hansen, H. I.; Thoft-Christensen, Palle

The main problem in designing ultra-long span suspension bridges is flutter. A solution to this problem might be to introduce an active flap control system to increase the flutter wind velocity. The investigated flap control system consists of flaps integrated in the bridge girder so each flap...... is the streamlined part of the edge of the girder. Additional aerodynamic derivatives are shown for the flaps and it is shown how methods already developed can be used to estimate the flutter wind velocity for a bridge section with flaps. As an example, the flutter wind velocity is calculated for different flap...... configurations for a bridge section model by using aerodynamic derivatives for a flat plate. The example shows that different flap configurations can either increase or decrease the flutter wind velocity. for optimal flap configurations flutter will not occur....

Active aerodynamic stabilisation of long suspension bridges

DEFF Research Database (Denmark)

Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

2004-01-01

The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension 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 aerodynamic motion around equilibriun is developed. The model is validated through comparison with finite element calculations and wind tunnel experimental data on the Great Belt East Bridge in Denmark. The developed...... active control scheme is local in that the flap control signal at a given longitudinal position along the bridge only depends on local motion measurements. The analysis makes use of the Nyquist stability criteria and an anlysis of the sensitivity function for stability analysis. The analysis shows...

Erection of the Rokko island bridge superstructure. Rokko island kyojobu koji no seko

Energy Technology Data Exchange (ETDEWEB)

Tanino, A; Sakai, Y; Morikawa, Y; Sakoda, H; Egami, T; Maeda, Y; Shikata, H; Miyazaki, K [Kawasaki Heavy Industries, Ltd., Tokyo (Japan)

1993-10-20