A diketiminate-bound diiron complex with a bridging carbonate ligand

PubMed Central

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

Informational Entropy and Bridge Scour Estimation under Complex Hydraulic Scenarios

NASA Astrophysics Data System (ADS)

Pizarro, Alonso; Link, Oscar; Fiorentino, Mauro; Samela, Caterina; Manfreda, Salvatore

2017-04-01

Bridges are important for society because they allow social, cultural and economic connectivity. Flood events can compromise the safety of bridge piers up to the complete collapse. The Bridge Scour phenomena has been described by empirical formulae deduced from hydraulic laboratory experiments. The range of applicability of such models is restricted by the specific hydraulic conditions or flume geometry used for their derivation (e.g., water depth, mean flow velocity, pier diameter and sediment properties). We seek to identify a general formulation able to capture the main dynamic of the process in order to cover a wide range of hydraulic and geometric configuration, allowing to extend our analysis in different contexts. Therefore, exploiting the Principle of Maximum Entropy (POME) and applying it on the recently proposed dimensionless Effective flow work, W*, we derived a simple model characterized by only one parameter. The proposed Bridge Scour Entropic (BRISENT) model shows good performances under complex hydraulic conditions as well as under steady-state flow. Moreover, the model was able to capture the evolution of scour in several hydraulic configurations even if the model contains only one parameter. Furthermore, results show that the model parameter is controlled by the geometric configurations of the experiment. This offers a possible strategy to obtain a priori model parameter calibration. The BRISENT model represents a good candidate for estimating the time-dependent scour depth under complex hydraulic scenarios. The authors are keen to apply this idea for describing the scour behavior during a real flood event. Keywords: Informational entropy, Sediment transport, Bridge pier scour, Effective flow work.

The Ndc80 complex bridges two Dam1 complex rings

PubMed Central

Kim, Jae ook; Zelter, Alex; Umbreit, Neil T; Bollozos, Athena; Riffle, Michael; Johnson, Richard; MacCoss, Michael J; Asbury, Charles L; Davis, Trisha N

2017-01-01

Strong kinetochore-microtubule attachments are essential for faithful segregation of sister chromatids during mitosis. The Dam1 and Ndc80 complexes are the main microtubule binding components of the Saccharomyces cerevisiae kinetochore. Cooperation between these two complexes enhances kinetochore-microtubule coupling and is regulated by Aurora B kinase. We show that the Ndc80 complex can simultaneously bind and bridge across two Dam1 complex rings through a tripartite interaction, each component of which is regulated by Aurora B kinase. Mutations in any one of the Ndc80p interaction regions abrogates the Ndc80 complex’s ability to bind two Dam1 rings in vitro, and results in kinetochore biorientation and microtubule attachment defects in vivo. We also show that an extra-long Ndc80 complex, engineered to space the two Dam1 rings further apart, does not support growth. Taken together, our work suggests that each kinetochore in vivo contains two Dam1 rings and that proper spacing between the rings is vital. DOI: http://dx.doi.org/10.7554/eLife.21069.001 PMID:28191870

Characterization of Trinuclear Oxo Bridged Cobalt Complexes in Isolation

NASA Astrophysics Data System (ADS)

Lang, Johannes; Fries, Daniela V.; Niedner-Schatteburg, Gereon

2018-05-01

This study elucidates molecular structures, fragmentation pathways and relative stabilities of isolated trinuclear oxo bridged cobalt complexes of the structural type [Co3O(OAc)6(Py)n]+ (OAc=acetate, Py=pyridine, n=0, 1, 2, 3). We present infrared multiple photon dissociation (IR-MPD) spectra in combination with quantum chemical calculations. They indicate that the coordination of axial pyridine ligands to the [Co3O(OAc)6]+ subunit disturbs the triangular geometry of the Co3O core. [Co3O(OAc)6]+ exhibits a nearly equilateral triangular Co3O core geometry. The coordination of one or two pyridine ligands disturbs this arrangement resulting in isosceles triangular Co3O core geometries (in the cases of n=1 and 2). Coordination of three pyridine ligands (n=3) results in an equilateral triangular Co3O core geometry as in the case of n=0. Collision induced dissociation (CID) studies reveal that the complexes undergo a consecutive elimination of pyridine and acetate ligands with increasing excitation energy. Relative stabilities of the complexes decrease with the number of coordinated pyridine ligands. The presented results help to gain a fundamental insight into the molecular structure of trinuclear oxo bridged cobalt complexes void of any external effects such as crystal packing or solvation.

54. STEEL COMPLEX FROM CLARK AVENUE BRIDGE, LOOKING NORTHEAST. FOUNDRY ...

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

54. STEEL COMPLEX FROM CLARK AVENUE BRIDGE, LOOKING NORTHEAST. FOUNDRY IN FOREGROUND, INGOT MOLDS ON TRACK AT RIGHT, BASIC OXYGEN FURNACE ON TRACK AT RIGHT. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

Combinatorial synthesis of bimetallic complexes with three halogeno bridges.

PubMed

Gauthier, Sébastien; Quebatte, Laurent; Scopelliti, Rosario; Severin, Kay

2004-06-07

Methods for the synthesis of bimetallic complexes in which two different metal fragments are connected by three chloro or bromo bridges are reported. The reactions are general, fast, and give rise to structurally defined products in quantitative yields. Therefore, they are ideally suited for generating a library of homo- and heterobimetallic complexes in a combinatorial fashion. This is of special interest for applications in homogeneous catalysis. Selected members of this library were synthesized and comprehensively characterized; single-crystal X-ray analyses were performed for 15 new bimetallic compounds.

Spin exchange effects on the physicochemical properties of tetraoxolene-bridged bimetallic complexes.

PubMed

Guo, Dong; McCusker, James K

2007-04-16

The synthesis, physical, and spectroscopic properties of a series of metal complexes bridged by the redox-active chloranilate ligand are described. Compounds containing the (CAcat,cat)4- ligand, where (CAcat,cat)4- represents the fully reduced aromatic form of chloranilate, have been prepared by two different routes from H2CA and H4CA starting materials; the corresponding (CAsq,cat)3- analogue was obtained by one-electron oxidation with decamethylferrocenium tetrafluoroborate. Homo- and heterobimetallic complexes containing CrIII and GaIII with chloranilate have been prepared, yielding the following six complexes: [Ga2(tren)2(CAcat,cat)](BPh4)2 (1), [Ga2(tren)2(CAsq,cat)](BPh4)2(BF4) (2), [GaCr(tren)2(CAcat,cat)](BPh4)2 (3), [GaCr(tren)2(CAsq,cat)](BPh4)2(BF4) (4), [Cr2(tren)2(CAcat,cat)] (BPh4)2 (5), and [Cr2(tren)2(CAsq,cat)](BPh4)2(BF4) (6) (where tren is tris(2-aminoethyl)amine). Single-crystal X-ray structures have been obtained for complexes 1, 3, and 5; nearly identical C-C bond distances within the quinoidal ligand confirm the aromatic character of the bridge in each case. Complex 2 exhibits a temperature-independent magnetic moment of microeff = 1.64 +/- 0.04 microB in the solid state between 4 and 350 K, consistent with the CAsq,cat formulation of the ligand and an S = 1/2 ground state for complex 2. Complex 3 exhibits a value of microeff = 3.44 +/- 0.09 microB that is also temperature-independent, indicating an S = 3/2 ground state. Complexes 4-6 are all influenced by Heisenberg spin exchange. The temperature-independent behavior of complexes 4 and 6 indicate the presence of strong antiferromagnetic exchange between the CrIII and the (sq,cat) bridging radical yielding well-isolated ground states of S = 1 and 5/2 for 4 and 6, respectively. In contrast, complex 5 exhibits a weak intramolecular antiferromagnetic exchange interaction between the two CrIII centers (J = -2 cm-1 for H = -2Jŝ1.ŝ2) via superexchange through the diamagnetic CAcat,cat bridge. The

Unique behaviour of dinitrogen-bridged dimolybdenum complexes bearing pincer ligand towards catalytic formation of ammonia.

PubMed

Tanaka, Hiromasa; Arashiba, Kazuya; Kuriyama, Shogo; Sasada, Akira; Nakajima, Kazunari; Yoshizawa, Kazunari; Nishibayashi, Yoshiaki

2014-04-28

It is vital to design effective nitrogen fixation systems that operate under mild conditions, and to this end we recently reported an example of the catalytic formation of ammonia using a dinitrogen-bridged dimolybdenum complex bearing a pincer ligand, where up to twenty three equivalents of ammonia were produced based on the catalyst. Here we study the origin of the catalytic behaviour of the dinitrogen-bridged dimolybdenum complex bearing the pincer ligand with density functional theory calculations, based on stoichiometric and catalytic formation of ammonia from molecular dinitrogen under ambient conditions. Comparison of di- and mono-molybdenum systems shows that the dinitrogen-bridged dimolybdenum core structure plays a critical role in the protonation of the coordinated molecular dinitrogen in the catalytic cycle.

The effects of transistor source-to-gate bridging faults in complex CMOS gates

NASA Astrophysics Data System (ADS)

Visweswaran, G. S.; Ali, Akhtar-Uz-Zaman M.; Lala, Parag K.; Hartmann, Carlos R. P.

1991-06-01

A study of the effect of gate-to-source bridging faults in the pull-up section of a complex CMOS gate is presented. The manifestation of these faults depends on the resistance value of the connection causing the bridging. It is shown that such faults manifest themselves either as stuck-at or stuck-open faults and can be detected by tests for stuck-at and stuck-open faults generated for the equivalent logic current. It is observed that for transistor channel lengths larger than 1 microns there exists a range of values of the bridging resistance for which the fault behaves as a pseudo-stuck-open fault.

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

PubMed

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.

Ammonia formation by a thiolate-bridged diiron amide complex as a nitrogenase mimic

NASA Astrophysics Data System (ADS)

Li, Yang; Li, Ying; Wang, Baomin; Luo, Yi; Yang, Dawei; Tong, Peng; Zhao, Jinfeng; Luo, Lun; Zhou, Yuhan; Chen, Si; Cheng, Fang; Qu, Jingping

2013-04-01

Although nitrogenase enzymes routinely convert molecular nitrogen into ammonia under ambient temperature and pressure, this reaction is currently carried out industrially using the Haber-Bosch process, which requires extreme temperatures and pressures to activate dinitrogen. Biological fixation occurs through dinitrogen and reduced NxHy species at multi-iron centres of compounds bearing sulfur ligands, but it is difficult to elucidate the mechanistic details and to obtain stable model intermediate complexes for further investigation. Metal-based synthetic models have been applied to reveal partial details, although most models involve a mononuclear system. Here, we report a diiron complex bridged by a bidentate thiolate ligand that can accommodate HN=NH. Following reductions and protonations, HN=NH is converted to NH3 through pivotal intermediate complexes bridged by N2H3- and NH2- species. Notably, the final ammonia release was effected with water as the proton source. Density functional theory calculations were carried out, and a pathway of biological nitrogen fixation is proposed.

A Dicobalt Complex with an Unsymmetrical Quinonoid Bridge Isolated in Three Units of Charge: A Combined Structural, (Spectro)electrochemical, Magnetic and Spectroscopic Study.

PubMed

van der Meer, Margarethe; Rechkemmer, Yvonne; Frank, Uta; Breitgoff, Frauke D; Hohloch, Stephan; Su, Cheng-Yong; Neugebauer, Petr; Marx, Raphael; Dörfel, María; van Slageren, Joris; Sarkar, Biprajit

2016-09-19

Quinonoid ligands are excellent bridges for generating redox-rich dinuclear assemblies. A large majority of these bridges are symmetrically substituted, with examples of unsymmetrically substituted quinonoid bridges being extremely rare. We present here a dicobalt complex in its various redox states with an unsymmetrically substituted quinonoid bridging ligand. Two homovalent forms and one mixed-valent form have been isolated and characterized by single crystal X-ray diffraction. The complex displays a large comproportionation constant for the mixed-valent state which is three orders of magnitude higher than that observed for the analogous complex with a symmetrically substituted bridge. Results from electrochemistry, UV/Vis/NIR spectroelectrochemistry, SQUID magnetometry, multi-frequency EPR spectroscopy and FIR spectroscopy are used to probe the electronic structures of these complexes. FIR provides direct evidence of exchange coupling. The results presented here display the advantages of using an unsymmetrically substituted bridge: site specific redox chemistry, high thermodynamic stabilization of the mixed-valent form, isolation and crystallization of various redox forms of the complex. This work represents an important step on the way to generating heterodinuclear complexes for use in cooperative catalysis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

trans-Methylpyridine cyclen versus cross-bridged trans-methylpyridine cyclen. Synthesis, acid-base and metal complexation studies (metal = Co2+, Cu2+, and Zn2+).

PubMed

Bernier, Nicolas; Costa, Judite; Delgado, Rita; Félix, Vítor; Royal, Guy; Tripier, Raphaël

2011-05-07

The synthesis of the cross-bridged cyclen CRpy(2) {4,10-bis((pyridin-2-yl)methyl)-1,4,7,10-tetraazabicyclo[5.5.2]tetradecane}, a constrained analogue of the previously described trans-methylpyridine cyclen Cpy(2) is reported. The additional ethylene bridge confers to CRpy(2) proton-sponge type behaviour which was explored by NMR and potentiometric studies. Transition metal complexes have been synthesized (by complexation of both ligands with Co(2+), Cu(2+) and Zn(2+)) and characterized in solution and in the solid state. The single crystal X-ray structures of [CoCpy(2)](2+), [CuCpy(2)](2+) and [ZnCpy(2)](2+) complexes were determined. Stability constants of the complexes, including those of the cross-bridged derivative, were determined using potentiometric titration data and the kinetic inertness of the [CuCRpy(2)](2+) complex in an acidic medium (half-life values) was evaluated by spectrophotometry. The pre-organized structure of the cross-bridged ligand imposes an additional strain for the complexation leading to complexes with smaller thermodynamic stability in comparison with the related non-bridged ligand. The electrochemical study involving cyclic voltammetry underlines the importance of the ethylene cross-bridge on the redox properties of the transition metal complexes.

Trinuclear Mn(II) complex with paramagnetic bridging 1,2,3-dithiazolyl ligands.

PubMed

Sullivan, David J; Clérac, Rodolphe; Jennings, Michael; Lough, Alan J; Preuss, Kathryn E

2012-11-18

The first metal coordination complex of a radical ligand based on the 1,2,3-dithiazolyl heterocycle is reported. 6,7-Dimethyl-1,4-dioxo-naphtho[2,3-d][1,2,3]dithiazolyl acts as a bridging ligand in the volatile trinuclear Mn(hfac)(2)-Rad-Mn(hfac)(2)-Rad-Mn(hfac)(2) complex (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-). The Mn(II) and radical ligand spins are coupled anti-ferromagnetically (AF) resulting in an S(T) = 13/2 spin ground state.

Salt Bridge Rearrangement (SaBRe) Explains the Dissociation Behavior of Noncovalent Complexes

NASA Astrophysics Data System (ADS)

Loo, Rachel R. Ogorzalek; Loo, Joseph A.

2016-06-01

Native electrospray ionization-mass spectrometry, with gas-phase activation and solution compositions that partially release subcomplexes, can elucidate topologies of macromolecular assemblies. That so much complexity can be preserved in gas-phase assemblies is remarkable, although a long-standing conundrum has been the differences between their gas- and solution-phase decompositions. Collision-induced dissociation of multimeric noncovalent complexes typically distributes products asymmetrically (i.e., by ejecting a single subunit bearing a large percentage of the excess charge). That unexpected behavior has been rationalized as one subunit "unfolding" to depart with more charge. We present an alternative explanation based on heterolytic ion-pair scission and rearrangement, a mechanism that inherently partitions charge asymmetrically. Excessive barriers to dissociation are circumvented in this manner, when local charge rearrangements access a lower-barrier surface. An implication of this ion pair consideration is that stability differences between high- and low-charge state ions usually attributed to Coulomb repulsion may, alternatively, be conveyed by attractive forces from ion pairs (salt bridges) stabilizing low-charge state ions. Should the number of ion pairs be roughly inversely related to charge, symmetric dissociations would be favored from highly charged complexes, as observed. Correlations between a gas-phase protein's size and charge reflect the quantity of restraining ion pairs. Collisionally-facilitated salt bridge rearrangement (SaBRe) may explain unusual size "contractions" seen for some activated, low charge state complexes. That some low-charged multimers preferentially cleave covalent bonds or shed small ions to disrupting noncovalent associations is also explained by greater ion pairing in low charge state complexes.

Salt Bridge Rearrangement (SaBRe) Explains the Dissociation Behavior of Noncovalent Complexes.

PubMed

Loo, Rachel R Ogorzalek; Loo, Joseph A

2016-06-01

Native electrospray ionization-mass spectrometry, with gas-phase activation and solution compositions that partially release subcomplexes, can elucidate topologies of macromolecular assemblies. That so much complexity can be preserved in gas-phase assemblies is remarkable, although a long-standing conundrum has been the differences between their gas- and solution-phase decompositions. Collision-induced dissociation of multimeric noncovalent complexes typically distributes products asymmetrically (i.e., by ejecting a single subunit bearing a large percentage of the excess charge). That unexpected behavior has been rationalized as one subunit "unfolding" to depart with more charge. We present an alternative explanation based on heterolytic ion-pair scission and rearrangement, a mechanism that inherently partitions charge asymmetrically. Excessive barriers to dissociation are circumvented in this manner, when local charge rearrangements access a lower-barrier surface. An implication of this ion pair consideration is that stability differences between high- and low-charge state ions usually attributed to Coulomb repulsion may, alternatively, be conveyed by attractive forces from ion pairs (salt bridges) stabilizing low-charge state ions. Should the number of ion pairs be roughly inversely related to charge, symmetric dissociations would be favored from highly charged complexes, as observed. Correlations between a gas-phase protein's size and charge reflect the quantity of restraining ion pairs. Collisionally-facilitated salt bridge rearrangement (SaBRe) may explain unusual size "contractions" seen for some activated, low charge state complexes. That some low-charged multimers preferentially cleave covalent bonds or shed small ions to disrupting noncovalent associations is also explained by greater ion pairing in low charge state complexes. Graphical Abstract ᅟ.

Reversible double oxidation and protonation of the non-innocent bridge in a nickel(II) salophen complex.

PubMed

de Bellefeuille, David; Askari, Mohammad S; Lassalle-Kaiser, Benedikt; Journaux, Yves; Aukauloo, Ally; Orio, Maylis; Thomas, Fabrice; Ottenwaelder, Xavier

2012-12-03

Substitution on the aromatic bridge of a nickel(II) salophen complex with electron-donating dimethylamino substituents creates a ligand with three stable, easily and reversibly accessible oxidation states. The one-electron-oxidized product is characterized as a nickel(II) radical complex with the radical bore by the central substituted aromatic ring, in contrast to other nickel(II) salen or salophen complexes that oxidize on the phenolate moieties. The doubly oxidized product, a singlet species, is best described as having an iminobenzoquinone bridge with a vinylogous distribution of bond lengths between the dimethylamino substituents. Protonation of the dimethylamino substituents inhibits these redox processes on the time scale of cyclovoltammetry, but electrolysis and chemical oxidation are consistent with deprotonation occurring concomitantly with electron transfer to yield the mono- and dioxidized species described above.

Dianionic Carbon-Bridged Scandium-Copper/Silver Heterobimetallic Complexes: Synthesis, Bonding, and Reactivity.

PubMed

Wang, Chen; Xiang, Li; Yang, Yan; Fang, Jian; Maron, Laurent; Leng, Xuebing; Chen, Yaofeng

2018-04-11

Alkylidene-bridged scandium-copper/silver heterobimetallic complexes were synthesized and structurally characterized. The complexes contain different Sc-C and M-C (M=Cu I , Ag I ) bonds. The reactivity of the scandium-copper heterobimetallic complex was also studied, which reveals that the heterobimetallic complex is a reaction intermediate for the transmetalation of akylidene group from Sc III to Cu I . The scandium-copper heterobimetallic complex also undergoes an addition reaction with CO, resulting in the formation of a new C=C double bond. DFT calculations were used to study the bonding and the subsequent reactivity with CO of the scandium-copper heterobimetallic complex. It clearly demonstrates a cooperative effect between the two metal centers through the formation of a direct Sc⋅⋅⋅Cu interaction that drives the reactivity with CO. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cytotoxic hydrogen bridged ruthenium quinaldamide complexes showing induced cancer cell death by apoptosis.

PubMed

Lord, Rianne M; Allison, Simon J; Rafferty, Karen; Ghandhi, Laura; Pask, Christopher M; McGowan, Patrick C

2016-08-16

This report presents the first known p-cymene ruthenium quinaldamide complexes which are stabilised by a hydrogen-bridging atom, [{(p-cym)Ru(II)X(N,N)}{H(+)}{(N,N)XRu(II)(p-cym)}][PF6] (N,N = functionalised quinaldamide and X = Cl or Br). These complexes are formed by a reaction of [p-cymRu(μ-X)2]2 with a functionalised quinaldamide ligand. When filtered over NH4PF6, and under aerobic conditions the equilibrium of NH4PF6 ⇔ NH3 + HPF6 enables incorporation of HPF6 and the stabilisation of two monomeric ruthenium complexes by a bridging H(+), which are counter-balanced by a PF6 counterion. X-ray crystallographic analysis is presented for six new structures with OO distances of 2.420(4)-2.448(15) Å, which is significant for strong hydrogen bonds. Chemosensitivity studies against HCT116, A2780 and cisplatin-resistant A2780cis human cancer cells showed the ruthenium complexes with a bromide ancillary ligand to be more potent than those with a chloride ligand. The 4'-fluoro compounds show a reduction in potency for both chloride and bromide complexes against all cell lines, but an increase in selectivity towards cancer cells compared to non-cancer ARPE-19 cells, with a selectivity index >1. Mechanistic studies showed a clear correlation between IC50 values and induction of cell death by apoptosis.

Synthesis and reactivity of NHC-supported Ni2(μ(2)-η(2),η(2)-S2)-bridging disulfide and Ni2(μ-S)2-bridging sulfide complexes.

PubMed

Olechnowicz, Frank; Hillhouse, Gregory L; Jordan, Richard F

2015-03-16

The (IPr)Ni scaffold stabilizes low-coordinate, mononuclear and dinuclear complexes with a diverse range of sulfur ligands, including μ(2)-η(2),η(2)-S2, η(2)-S2, μ-S, and μ-SH motifs. The reaction of {(IPr)Ni}2(μ-Cl)2 (1, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) with S8 yields the bridging disulfide species {(IPr)ClNi}2(μ(2)-η(2),η(2)-S2) (2). Complex 2 reacts with 2 equiv of AdNC (Ad = adamantyl) to yield a 1:1 mixture of the terminal disulfide compound (IPr)(AdNC)Ni(η(2)-S2) (3a) and trans-(IPr)(AdNC)NiCl2 (4a). 2 also reacts with KC8 to produce the Ni-Ni-bonded bridging sulfide complex {(IPr)Ni}2(μ-S)2 (6). Complex 6 reacts with H2 to yield the bridging hydrosulfide compound {(IPr)Ni}2(μ-SH)2 (7), which retains a Ni-Ni bond. 7 is converted back to 6 by hydrogen atom abstraction by 2,4,6-(t)Bu3-phenoxy radical. The 2,6-diisopropylphenyl groups of the IPr ligand provide lateral steric protection of the (IPr)Ni unit but allow for the formation of Ni-Ni-bonded dinuclear species and electronically preferred rather than sterically preferred structures.

2,3-Di(2-pyridyl)-5-phenylpyrazine: a NN-CNN-type bridging ligand for dinuclear transition-metal complexes.

PubMed

Wu, Si-Hai; Zhong, Yu-Wu; Yao, Jiannian

2013-07-01

A new bridging ligand, 2,3-di(2-pyridyl)-5-phenylpyrazine (dpppzH), has been synthesized. This ligand was designed so that it could bind two metals through a NN-CNN-type coordination mode. The reaction of dpppzH with cis-[(bpy)2RuCl2] (bpy = 2,2'-bipyridine) affords monoruthenium complex [(bpy)2Ru(dpppzH)](2+) (1(2+)) in 64 % yield, in which dpppzH behaves as a NN bidentate ligand. The asymmetric biruthenium complex [(bpy)2Ru(dpppz)Ru(Mebip)](3+) (2(3+)) was prepared from complex 1(2+) and [(Mebip)RuCl3] (Mebip = bis(N-methylbenzimidazolyl)pyridine), in which one hydrogen atom on the phenyl ring of dpppzH is lost and the bridging ligand binds to the second ruthenium atom in a CNN tridentate fashion. In addition, the RuPt heterobimetallic complex [(bpy)2Ru(dpppz)Pt(C≡CPh)](2+) (4(2+)) has been prepared from complex 1(2+), in which the bridging ligand binds to the platinum atom through a CNN binding mode. The electronic properties of these complexes have been probed by using electrochemical and spectroscopic techniques and studied by theoretical calculations. Complex 1(2+) is emissive at room temperature, with an emission λmax = 695 nm. No emission was detected for complex 2(3+) at room temperature in MeCN, whereas complex 4(2+) displayed an emission at about 750 nm. The emission properties of these complexes are compared to those of previously reported Ru and RuPt bimetallic complexes with a related ligand, 2,3-di(2-pyridyl)-5,6-diphenylpyrazine. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, crystal structure and spectroscopic and electrochemical properties of bridged trisbenzoato copper-zinc heterobinuclear complex of 2,2‧-bipyridine

NASA Astrophysics Data System (ADS)

Koch, Angira; Kumar, Arvind; Singh, Suryabhan; Borthakur, Rosmita; Basumatary, Debajani; Lal, Ram A.; Shangpung, Sankey

2015-03-01

The synthesis of the heterobinuclear copper-zinc complex [CuZn(bz)3(bpy)2]ClO4 (bz = benzoate) from benzoic acid and bipyridine is described. Single crystal X-ray diffraction studies of the heterobinuclear complex reveals the geometry of the benzoato bridged Cu(II)-Zn(II) centre. The copper or zinc atom is pentacoordinate, with two oxygen atoms from bridging benzoato groups and two nitrogen atoms from one bipyridine forming an approximate plane and a bridging oxygen atom from a monodentate benzoate group. The Cu-Zn distance is 3.345 Å. The complex is normal paramagnetic having μeff value equal to 1.75 BM, ruling out the possibility of Cu-Cu interaction in the structural unit. The ESR spectrum of the complex in CH3CN at RT exhibit an isotropic four line spectrum centred at g = 2.142 and hyperfine coupling constants Aav = 63 × 10-4 cm-1, characteristic of a mononuclear square-pyramidal copper(II) complexes. At LNT, the complex shows an isotropic spectrum with g|| = 2.254 and g⊥ = 2.071 and A|| = 160 × 10-4 cm-1. The Hamiltonian parameters are characteristic of distorted square pyramidal geometry. Cyclic voltammetric studies of the complex have indicated quasi-reversible behaviour in acetonitrile solution.

Redox-Controlled Olefin (Co)Polymerization Catalyzed by Ferrocene-Bridged Phosphine-Sulfonate Palladium Complexes.

PubMed

Chen, Min; Yang, Bangpei; Chen, Changle

2015-12-14

The facile and reversible interconversion between neutral and oxidized forms of palladium complexes containing ferrocene-bridged phosphine sulfonate ligands was demonstrated. The activity of these palladium complexes could be controlled using redox reagents during ethylene homopolymerization, ethylene/methyl acrylate copolymerization, and norbornene oligomerization. Specifically in norbornene oligomerization, the neutral complexes were not active at all whereas the oxidized counterparts showed appreciable activity. In situ switching between the neutral and oxidized forms resulted in an interesting "off" and "on" behavior in norbornene oligomerization. This work provides a new strategy to control the olefin polymerization process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Acetate-Bridged Platinum(III) Complexes Derived from Cisplatin

PubMed Central

Wilson, Justin J.

2012-01-01

Oxidation of the acetate-bridged half-lantern platinum(II) complex, cis-[PtII(NH3)2(µ-OAc)2PtII(NH3)2](NO3)2, [1](NO3)2, with iodobenzene dichloride or bromine generates the halide-capped platinum(III) species, cis-[XPtIII(NH3)2(µ-OAc)2PtIII(NH3)2X](NO3)2, where X is Cl in [2](NO3)2, or Br in [3](NO3)2, respectively. These three complexes, characterized structurally by X-ray crystallography, feature short (≈ 2.6 Å) Pt–Pt separations, consistent with formation of a formal metal-metal bond upon oxidation. Elongated axial Pt–X distances occur, reflecting the strong trans influence of the metal-metal bond. The three structures are compared to those of other known dinuclear platinum complexes. A combination of 1H, 13C, 14N, and 195Pt NMR spectroscopy was used to characterize [1]2+–[3]2+ in solution. All resonances shift downfield upon oxidation of [1]2+ to [2]2+ and [3]2+. For the platinum(III) complexes, the 14N and 195Pt resonances exhibit decreased linewidths by comparison to those of [1]2+. Density functional theory (DFT) calculations suggest that the decrease in 14N linewidth arises from a diminished electric field gradient (EFG) at the 14N nuclei in the higher valent compounds. The oxidation of [1](NO3)2 with the alternative oxidizing agent, bis(trifluoroacetoxy) iodobenzene, affords the novel tetranuclear complex, cis-[(O2CCF3)PtIII(NH3)2(µ-OAc)2PtIII(NH3)(µ-NH2)]2(NO3)4, [4](NO3)4, also characterized structurally by X-ray crystallography. In solution, this complex exists as a mixture of species, the identities of which are proposed. PMID:22946515

A series of tetraazalene radical-bridged M2 (M = CrIII, MnII, FeII, CoII) complexes with strong magnetic exchange coupling.

PubMed

DeGayner, Jordan A; Jeon, Ie-Rang; Harris, T David

2015-11-13

The ability of tetraazalene radical bridging ligands to mediate exceptionally strong magnetic exchange coupling across a range of transition metal complexes is demonstrated. The redox-active bridging ligand N , N ', N '', N '''-tetra(2-methylphenyl)-2,5-diamino-1,4-diiminobenzoquinone ( NMePh LH 2 ) was metalated to give the series of dinuclear complexes [(TPyA) 2 M 2 ( NMePh L 2- )] 2+ (TPyA = tris(2-pyridylmethyl)amine, M = Mn II , Fe II , Co II ). Variable-temperature dc magnetic susceptibility data for these complexes reveal the presence of weak superexchange interactions between metal centers, and fits to the data provide coupling constants of J = -1.64(1) and -2.16(2) cm -1 for M = Mn II and Fe II , respectively. One-electron reduction of the complexes affords the reduced analogues [(TPyA) 2 M 2 ( NMePh L 3- ˙)] + . Following a slightly different synthetic procedure, the related complex [(TPyA) 2 CrIII2( NMePh L 3- ˙)] 3+ was obtained. X-ray diffraction, cyclic voltammetry, and Mössbauer spectroscopy indicate the presence of radical NMePh L 3- ˙ bridging ligands in these complexes. Variable-temperature dc magnetic susceptibility data of the radical-bridged species reveal the presence of strong magnetic interactions between metal centers and ligand radicals, with simulations to data providing exchange constants of J = -626(7), -157(7), -307(9), and -396(16) cm -1 for M = Cr III , Mn II , Fe II , and Co II , respectively. Moreover, the strength of magnetic exchange in the radical-bridged complexes increases linearly with decreasing M-L bond distance in the oxidized analogues. Finally, ac magnetic susceptibility measurements reveal that [(TPyA) 2 Fe 2 ( NMePh L 3- ˙)] + behaves as a single-molecule magnet with a relaxation barrier of U eff = 52(1) cm -1 . These results highlight the ability of redox-active tetraazalene bridging ligands to enable dramatic enhancement of magnetic exchange coupling upon redox chemistry and provide a rare opportunity to examine

A synthetic NO reduction cycle on a bis(pyrazolato)-bridged dinuclear ruthenium complex including photo-induced transformation.

PubMed

Arikawa, Yasuhiro; Hiura, Junko; Tsuchii, Chika; Kodama, Mika; Matsumoto, Naoki; Umakoshi, Keisuke

2018-05-17

A synthetic NO reduction cycle (2NO + 2H+ + 2e- → N2O + H2O) on a dinuclear platform {(TpRu)2(μ-pz)2} (Tp = HB(pyrazol-1-yl)3) was achieved, where an unusual N-N coupling complex was included. Moreover, an interesting photo-induced conversion of the N-N coupling complex to an oxido-bridged complex was revealed.

A family of acetato-diphenoxo triply bridged dimetallic Zn(II)Ln(III) complexes: SMM behavior and luminescent properties.

PubMed

Oyarzabal, Itziar; Artetxe, Beñat; Rodríguez-Diéguez, Antonio; García, JoséÁngel; Seco, José Manuel; Colacio, Enrique

2016-06-21

Eleven dimetallic Zn(II)-Ln(III) complexes of the general formula [Zn(µ-L)(µ-OAc)Ln(NO3)2]·CH3CN (Ln(III) = Pr (1), Nd (2), Sm (3), Eu (4), Gd (5), Tb (6), Dy (7), Ho (8), Er (9), Tm (10), Yb (11)) have been prepared in a one-pot reaction from the compartmental ligand N,N'-dimethyl-N,N'-bis(2-hydroxy-3-formyl-5-bromo-benzyl)ethylenediamine (H2L). In all these complexes, the Zn(II) ions occupy the internal N2O2 site whereas the Ln(III) ions show preference for the O4 external site. Both metallic ions are bridged by an acetate bridge, giving rise to triple mixed diphenoxido/acetate bridged Zn(II)Ln(III) compounds. The Nd, Dy, Er and Yb complexes exhibit field induced single-ion magnet (SIM) behaviour, with Ueff values ranging from 14.12 to 41.55 K. The Er complex shows two relaxation processes, but only the second relaxation process with an energy barrier of 21.0 K has been characterized. The chromophoric L(2-) ligand is able to act as an "antenna" group, sensitizing the near-infrared (NIR) Nd(III) and Yb(III)-based luminescence in complexes 2 and 11 and therefore, both compounds can be considered as magneto-luminescent materials. In addition, the Sm(III), Eu(III) and Tb(III) derivatives exhibit characteristic emissions in the visible region.

Oxoiron(IV) Complex of the Ethylene-Bridged Dialkylcyclam Ligand Me2EBC.

PubMed

England, Jason; Prakash, Jai; Cranswick, Matthew A; Mandal, Debasish; Guo, Yisong; Münck, Eckard; Shaik, Sason; Que, Lawrence

2015-08-17

We report herein the first example of an oxoiron(IV) complex of an ethylene-bridged dialkylcyclam ligand, [Fe(IV)(O)(Me2EBC)(NCMe)](2+) (2; Me2EBC = 4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane). Complex 2 has been characterized by UV-vis, (1)H NMR, resonance Raman, Mössbauer, and X-ray absorption spectroscopy as well as electrospray ionization mass spectrometry, and its properties have been compared with those of the closely related [Fe(IV)(O)(TMC)(NCMe)](2+) (3; TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), the intensively studied prototypical oxoiron(IV) complex of the macrocyclic tetramethylcyclam ligand. Me2EBC has an N4 donor set nearly identical with that of TMC but possesses an ethylene bridge in place of the 1- and 8-methyl groups of TMC. As a consequence, Me2EBC is forced to deviate from the trans-I configuration typically found for Fe(IV)(O)(TMC) complexes and instead adopts a folded cis-V stereochemistry that requires the MeCN ligand to coordinate cis to the Fe(IV)═O unit in 2 rather than in the trans arrangement found in 3. However, switching from the trans geometry of 3 to the cis geometry of 2 did not significantly affect their ground-state electronic structures, although a decrease in ν(Fe═O) was observed for 2. Remarkably, despite having comparable Fe(IV/III) reduction potentials, 2 was found to be significantly more reactive than 3 in both oxygen-atom-transfer (OAT) and hydrogen-atom-transfer (HAT) reactions. A careful analysis of density functional theory calculations on the HAT reactivity of 2 and 3 revealed the root cause to be the higher oxyl character of 2, leading to a stronger O---H bond specifically in the quintet transition state.

Influence of ligand-bridged substitution on the exchange coupling constant of chromium-wheels host complexes: a density functional theory study

NASA Astrophysics Data System (ADS)

Sadeghi Googheri, Motahare; Abolhassani, Mohammad Reza; Mirzaei, Mahmoud

2018-05-01

Designing and introducing novel wheel-shaped supramolecular as host complexes with new magnetic properties is the theme of the day. So in this study, new eight binuclear chromium (III) complexes, as models of real chromium-wheel host complexes, were designed based on changing of bridged-ligands and exchange coupling constants (J) of them were calculated using the broken symmetry density functional theory approach. Substitution of fluorine ligand in fluoro-bridged model [Cr2F(tBuCO2)2(H2O)2(OH)4]-1 by halogen anions (Cl-, Br- and I- ) decreased the antiferromagnetic exchange coupling between Cr(III) centres such that by going from F- to I- the J values became more positive. In the case of hydroxo-bridged model [Cr2OH(tBuCO2)2(H2O)2(OH)4]-1, replacement of hydroxyl by methoxy anion (OMe-) strengthened the antiferromagnetic property of the complex but substitution by sulfanide (SH-) and amide (NH2-) anions weakened it and changed the nature of complexes to ferromagnetic. Because of their different magnetic properties, these new investigated complexes can be suggested as interesting synthetic targets. Also, the J value changes due to ligand substitution were evaluated and it was found that the Cr-X bond strength and partial charges of involved atoms were the most effective factors on it.

Movable bridge maintenance monitoring.

DOT National Transportation Integrated Search

2013-10-01

Movable bridges have particular maintenance issues, which cost considerably more than those of fixed bridges, : mostly because of the complex interaction of the mechanical, electrical and structural components. In order to track : maintenance and ope...

An unsupported metal hydroxide for the design of molecular μ-oxo bridged heterobimetallic complexes.

PubMed

Falzone, A J; Nguyen, J; Weare, W W; Sommer, R D; Boyle, P D

2014-02-28

A terminal and unsupported chromium(III) hydroxide is reported. The terminal hydroxide is used to synthesize the first example of a heterobimetallic Ti-O-Cr compound containing an unsupported μ-oxo bridge. The heterobimetallic complex exhibits a new absorbance at 288 nm (4.32 eV), which is assigned to a metal-to-metal charge transfer (MMCT) transition.

Movable bridge maintenance monitoring : [technical summary].

DOT National Transportation Integrated Search

2013-10-01

Maintenance costs for movable bridges are considerably higher than for fixed bridges, mostly because of the complex interaction of mechanical, electrical, and structural components. Malfunction of any component can cause unexpected failure of bridge ...

Roles of Bridging Ligand Topology and Conformation in Controlling Exchange Interactions between Paramagnetic Molybdenum Fragments in Dinuclear and Trinuclear Complexes.

PubMed

Ung VÂ, V&acaron;n Ân; Cargill Thompson, Alexander M. W.; Bardwell, David A.; Gatteschi, Dante; Jeffery, John C.; McCleverty, Jon A.; Totti, Federico; Ward, Michael D.

1997-07-30

The magnetic properties of two series of dinuclear complexes, and one trinuclear complex, have been examined as a function of the bridging pathway between the metal centers. The first series of dinuclear complexes is [{Mo(V)(O)(Tp)Cl}(2)(&mgr;-OO)], where "OO" is [1,4-O(C(6)H(4))(n)O](2)(-) (n = 1, 1; n = 2, 3), [4,4'-O(C(6)H(3)-2-Me)(2)O](2)(-) (4), or [1,3-OC(6)H(4)O](2)(-) (2) [Tp = tris(3,5-dimethylpyrazolyl)hydroborate]. The second series of dinuclear complexes is [{Mo(I)(NO)(Tp)Cl}(2)(&mgr;-NN)], where "NN" is 4,4'-bipyridyl (5), 3,3'-dimethyl-4,4'-bipyridine (6), 3,8-phenanthroline (7), or 2,7-diazapyrene (8). The trinuclear complex is [{Mo(V)(O)(Tp)Cl}(3)(1,3,5-C(6)H(3)O(3))] (9), whose crystal structure was determined [9.5CH(2)Cl(2): C(56)H(81)B(3)Cl(13)Mo(3)N(18)O(6); monoclinic, P2(1)/n; a = 13.443, b = 41.46(2), c = 14.314(6) Å; beta = 93.21(3) degrees; V = 7995(5) Å(3); Z = 4; R(1) = 0.106]. In these complexes, the sign and magnitude of the exchange coupling constant J is clearly related to both the topology and the conformation of the bridging ligand [where J is derived from H = -JS(1)().S(2)() for 1-8 and H = -J(S(1)().S(2)() + S(2)().S(3)() + S(1)().S(3)()) for 9]. The values are as follows: 1, -80 cm(-)(1); 2, +9.8 cm(-)(1); 3, -13.2 cm(-)(1); 4, -2.8 cm(-)(1); 5, -33 cm(-)(1); 6, -3.5 cm(-)(1); 7, -35.6 cm(-)(1); 8, -35.0 cm(-)(1); 9, +14.4 cm(-)(1). In particular the following holds: (1) J is negative (antiferromagnetic exchange) across the para-substituted bridges ligands of 1 and 3-8 but positive (ferromagnetic exchange) across the meta-substituted bridging ligands of 2 and 9. (2) J decreases in magnitude dramatically as the bridging ligand conformation changes from planar to twisted (compare 3 and 4, or 6 and 8). These observations are consistent with a spin-polarization mechanism for the exchange interaction, propagated across the pi-system of the bridging ligand by via overlap of bridging ligand p(pi) orbitals with the d(pi) magnetic

Catalytic Activity of Thiolate-Bridged Diruthenium Complexes Bearing Pendent Ether Moieties in the Oxidation of Molecular Dihydrogen.

PubMed

Yuki, Masahiro; Sakata, Ken; Kikuchi, Shoma; Kawai, Hiroyuki; Takahashi, Tsuyoshi; Ando, Masaki; Nakajima, Kazunari; Nishibayashi, Yoshiaki

2017-01-23

Thiolate-bridged diruthenium complexes bearing pendent ethers have been found to work as effective catalysts toward the oxidation of molecular dihydrogen into protons and electrons in water. The pendent ether moiety in the complex plays an important role to facilitate the proton transfer between the metal center and the external proton acceptor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigating the pharmacodynamic and magnetic properties of pyrophosphate-bridged coordination complexes

NASA Astrophysics Data System (ADS)

Ikotun, Oluwatayo (Tayo) F.

The multidentate nature of pyrophosphate makes it an attractive ligand for complexation of metal cations. The participation of pyrophosphate in a variety of biological pathways and its metal catalyzed hydrolysis has driven our investigation into its coordination chemistry. We have successfully synthesized a library of binuclear pyrophosphate bridge coordination complexes. The problem of pyrophosphate hydrolysis to phosphate in the presence of divalent metal ions was overcome by incorporating capping ligands such as 1,10-phenanthroline and 2,2'-bipyridine prior to the addition of the pyrophosphate. The magnetic properties of these complexes was investigated and magneto-structural analysis was conducted. The biological abundance of pyrophosphate and the success of metal based drugs such as cisplatin, prompted our investigation of the cytotoxic properties of M(II) pyrophosphate dimeric complexes (where M(II) is CoII, CuII, and NiII) in adriamycin resistant human ovarian cancer cells. Thess compounds were found to exhibit toxicity in the nanomolar to picomolar range. We conducted in vitro stability studies and the mechanism of cytoxicity was elucidated by performing DNA mobility and binding assays, enzyme inhibition assays, and in vitro oxidative stress studies.

Nucleophilic ring opening of bridging thietanes in open triosmium cluster complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, R.D.; Belinski, J.A.

1992-07-01

The complexes Os{sub 3}(CO){sub 9}({mu}{sub 3}-S)[{mu}-SCH{sub 2}CMe{sub 2}CMe{sub 2}CH{sub 2}] (1) and Os{sub 3}(CO){sub 9}({mu}{sub 3}-S)[{mu}-SCH{sub 2}CH{sub 2}CH{sub 2}] (2) were obtained from the reactions of Os{sub 3}(CO){sub 10}({mu}{sub 3}-S) with 3,3-dimethylthietane (DMT) and thietane, respectively, at -42 {degree}C in the presence of Me{sub 3}NO. Compound 1 was characterized by a single-crystal X-ray diffraction analysis and was found to contain a DMT group bridging two of the nonbonded metal atoms in the open cluster of three metal atoms by using both lone pairs of electrons on the sulfur atom. Compound 1 reacted with bis(triphenylphosphine)nitrogen(1+) chloride ([PPN]Cl) at 25 {degrees}C tomore » yield the salt [PPN][Os{sub 3}-(CO){sub 9}({mu}-SCH{sub 2}CMe{sub 2}CH{sub 2}Cl)({mu}{sub 3}-S)] (3; 76%), in which the chloride ion was added to one of the methylene groups of the DMT ring in a process that caused the ring to open by cleavage of one of the carbon-sulfur bonds. A 4-chloro-3,3-dimethylpropanethiolate ligand bridges the open edge of the anionic triosmium cluster. Compound 3 was converted to the neutral complex Os{sub 3}(CO){sub 9}[{mu}-SCH{sub 2}CMe{sub 2}CMe{sub 2}CH{sub 2}Cl]({mu}{sub 3}-S)({mu}-H) (4) by reaction with HCl at 25 {degrees}C. Compound 4 is structurally similar to 3, except that is contains a hydride ligand bridging one of the two metal-metal bonds. Compounds 1 and 2 react with HCl in CH{sub 2}Cl{sub 2} solvent to yield the neutral compounds 4 and Os{sub 3}(CO){sub 9}[{mu}-SCH{sub 2}CH{sub 2}CH{sub 2}Cl]({mu}{sub 3}-S)({mu}-H) (5) in 89% and 90% yields, respectively, in one step. 11 refs., 3 figs., 10 tabs.« less

Improvement in Titanium Complexes Bearing Schiff Base Ligands in the Ring-Opening Polymerization of L-Lactide: A Dinuclear System with Hydrazine-Bridging Schiff Base Ligands.

PubMed

Tseng, Hsi-Ching; Chen, Hsing-Yin; Huang, Yen-Tzu; Lu, Wei-Yi; Chang, Yu-Lun; Chiang, Michael Y; Lai, Yi-Chun; Chen, Hsuan-Ying

2016-02-15

A series of titanium (Ti) complexes bearing hydrazine-bridging Schiff base ligands were synthesized and investigated as catalysts for the ring-opening polymerization (ROP) of L-lactide (LA). Complexes with electron withdrawing or steric bulky groups reduced the catalytic activity. In addition, the steric bulky substituent on the imine groups reduced the space around the Ti atom and then reduced LA coordination with Ti atom, thereby reducing catalytic activity. All the dinuclear Ti complexes exhibited higher catalytic activity (approximately 10-60-fold) than mononuclear L(Cl-H)-TiOPr2 did. The strategy of bridging dinuclear Ti complexes with isopropoxide groups in the ROP of LA was successful, and adjusting the crowded heptacoordinated transition state by the bridging isopropoxide groups may be the key to our successful strategy.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, Michael A.; Hallen, Richard T.

1990-01-01

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately .pi.-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancilliary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H.sub.2 from mixed gas streams such as the produce gas from coal gasification processes.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, Michael A.; Hallen, Richard T.

1991-01-01

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately .pi.-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancilliary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H.sub.2 from mixed gas streams such as the product gas from coal gasification processes.

Synthesis and spectral characterization of trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes with Schiff bases.

PubMed

Singh, Atresh Kumar; Singh, Alok Kumar

2012-10-01

Some novel trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes of the general formula [Fe(3)O(OOCR)(3)(SB)(3)L(3)] (where R=C(13)H(27), C(15)H(31) or C(17)H(35,) HSB=Schiff bases and L=Ethanol) have been synthesized by the stepwise substitutions of acetate ions from μ(3)-oxo-hexa(acetato)tri(aqua)iron(II)diiron(III), first with straight chain carboxylic acids and then with Schiff bases. The complexes were characterized by elemental analyses, molecular weight determinations and spectral (electronic, infrared, FAB mass, Mössbauer and powder XRD) studies. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bridging nature of carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Mössbauer spectroscopic studies indicated two quadrupole-split doublets due to Fe(II) and Fe(III) ions at 80, 200 and 295K, confirming the complexes are mixed-valence species. This was also supported by the observed electronic spectra of the complexes. Magnetic susceptibility measurements displayed octahedral geometry around iron in mixed-valence state and a net antiferromagnetic exchange coupling via μ-oxo atom. Trinuclear nature of the complexes was confirmed by their molecular weight determination and FAB mass spectra. A plausible structure for these complexes has been established on the basis of spectral and magnetic moment data. Copyright © 2012 Elsevier B.V. All rights reserved.

Bimetallic ruthenium complexes bridged by divinylphenylene bearing oligo(ethylene glycol)methylether: synthesis, (spectro)electrochemistry and the lithium cation effect.

PubMed

Tian, Li Yan; Liu, Yuan Mei; Tian, Guang-Xuan; Wu, Xiang Hua; Li, Zhen; Kou, Jun-Feng; Ou, Ya-Ping; Liu, Sheng Hua; Fu, Wen-Fu

2014-03-14

A series of 1,4-disubstituted ruthenium-vinyl complexes, (E,E)-[{(PMe3)3(CO)ClRu}2(μ-HC=CH-Ar-CH=CH)], in which the 1,4-diethenylphenylene bridge bears two oligo(ethylene glycol)methyl ether side chains at different positions (2,5- and 2,3-positions), were prepared. The respective products were characterized by elemental analyses and NMR spectroscopy. The structures of complexes 1b and 1e were established by X-ray crystallography. The electronic properties of the complexes were investigated by cyclic voltammetry, and IR and UV-vis/NIR spectroscopies. Electrochemical studies showed that the 2,5-substituents better stabilized the mixed-valence states; the electrochemical behavior was greatly affected by lithium cations, especially complex 1g with 2,3-substituents, which was further supported by IR and UV-vis/NIR spectra changes. Spectroelectrochemical studies showed that the redox chemistry was dominated by the non-innocent character of the bridging fragment.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, M.A.; Hallen, R.T.

1991-10-15

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately [pi]-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancillary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H[sub 2] from mixed gas streams such as the product gas from coal gasification processes. 3 figures.

Bridged transition-metal complexes and uses thereof for hydrogen separation, storage and hydrogenation

DOEpatents

Lilga, M.A.; Hallen, R.T.

1990-08-28

The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately [pi]-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancillary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H[sub 2] from mixed gas streams such as the producer gas from coal gasification processes. 3 figs.

Alkoxy bridged binuclear rhenium (I) complexes as a potential sensor for β-amyloid aggregation.

PubMed

Sathish, Veerasamy; Babu, Eththilu; Ramdass, Arumugam; Lu, Zong-Zhan; Velayudham, Murugesan; Thanasekaran, Pounraj; Lu, Kuang-Lieh; Rajagopal, Seenivasan

2014-12-01

Alkoxy bridged binuclear rhenium(I) complexes are used as a probe for the selective and sensitive detection of aggregation of β-amyloid fibrils that are consorted with Alzheimer's disease (AD). The strong binding of the complexes is affirmed by the fluorescence enhancement and calculated binding constant value in the order of 10(5)M(-1) is obtained from the Scatchard plots. The binding of β-amyloid can be attributed to π-π stacking interaction of naphthalene moiety present in rhenium(I) complexes, and it is supported by docking studies. The selectivity is quite high towards other proteins and the formation of fibrils can be observed in the range of 30-40 nm through the AFM and TEM techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

High-Frequency Fe-H Vibrations in a Bridging Hydride Complex Characterized by NRVS and DFT.

PubMed

Pelmenschikov, Vladimir; Gee, Leland B; Wang, Hongxin; MacLeod, K Cory; McWilliams, Sean F; Skubi, Kazimer L; Cramer, Stephen P; Holland, Patrick L

2018-05-30

High-spin iron species with bridging hydrides have been detected in species trapped during nitrogenase catalysis, but there are few general methods of evaluating Fe-H bonds in high-spin multinuclear iron systems. An 57 Fe nuclear resonance vibrational spectroscopy (NRVS) study on an Fe(μ-H) 2 Fe model complex reveals Fe-H stretching vibrations for bridging hydrides at frequencies greater than 1200 cm -1 . These isotope-sensitive vibrational bands are not evident in infrared (IR) spectra, showing the power of NRVS for identifying hydrides in this high-spin iron system. Complementary density functional theory (DFT) calculations elucidate the normal modes of the rhomboidal iron hydride core. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two binuclear cyanide-bridged Cr(III)-Mn(III) complexes based-on [Cr(2,2'-bipy)(CN)4]- building block: synthesis, crystal structures and magnetic properties.

PubMed

Zhanga, Daopeng; Kong, Lingqian; Zhang, Hongyan

2015-01-01

Tetracyanide building block [Cr(2,2'-bipy)(CN)(4)]- and two bicompartimental Schiff-base based manganese(III) compounds have been employed to assemble cyanide-bridged heterometallic complexes, resulting in two cyanide-bridged CrIII-MnIII complexes: [Mn(L(1))(H(2)O)][Cr(2,2'-bipy)(CN)(4)]·CH(3)OH·2.5H(2)O (1) and [Mn(L(2))(H(2)O)][Cr(2,2'-bipy)(CN)(4)]·CH(3)OH·(3)H(2)O (2) (L1 = N,N'-(1,3-propylene)-bis(3-methoxysalicylideneiminate), L2 = N,N'-ethylene-bis(3-ethoxysalicylideneiminate)). Single X-ray diffraction analysis shows their similar cyanide-bridged binuclear structures, in which the cyanide precursor acting as monodentate ligand connects the manganese(III) ion. The binuclear complexes are self-complementary through coordinated aqua ligand and the free O4 compartment from the neighboring complex, giving H-bond linking dimer structure. Investigation over magnetic properties reveals the antiferromagnetic magnetic coupling between the cyanide-bridged Cr(III) and Mn(III) ions. A best-fit to the magnetic susceptibilities of these two complexes leads to the magnetic coupling constants J = -5.95 cm(-1), j = -0.61 cm(-1) (1) and J = -4.15 cm(-1), j = -0.57 cm(-1) (2), respectively.

Pentacoordinate and Hexacoordinate Mn(III) Complexes of Tetradentate Schiff-Base Ligands Containing Tetracyanidoplatinate(II) Bridges and Revealing Uniaxial Magnetic Anisotropy.

PubMed

Nemec, Ivan; Herchel, Radovan; Trávníček, Zdeněk

2016-12-08

Crystal structures and magnetic properties of polymeric and trinuclear heterobimetallic Mn III ···Pt II ···Mn III coordination compounds, prepared from the Ba[Pt(CN)₄] and [Mn(L4A/B)(Cl)] ( 1a / b ) precursor complexes, are reported. The polymeric complex [{Mn(L4A)}₂{μ⁴-Pt(CN)₄}] n ( 2a ), where H₂L4A = N , N '-ethylene-bis(salicylideneiminate), comprises the {Mn(L4A)} moieties covalently connected through the [Pt(CN)₄] 2- bridges, thus forming a square-grid polymeric structure with the hexacoordinate Mn III atoms. The trinuclear complex [{Mn(L4B)}₂{μ-Pt(CN)₄}] ( 2b ), where H₂L4B = N , N '-benzene-bis(4-aminodiethylene-salicylideneiminate), consists of two [{Mn(L4B)} moieties, involving pentacoordinate Mn III atoms, bridged through the tetracyanidoplatinate (II) bridges to which they are coordinated in a trans fashion. Both complexes possess uniaxial type of magnetic anisotropy, with D (the axial parameter of zero-field splitting) = -3.7(1) in 2a and -2.2(1) cm -1 in 2b . Furthermore, the parameters of magnetic anisotropy 2a and 2b were also thoroughly studied by theoretical complete active space self-consistent field (CASSCF) methods, which revealed that the former is much more sensitive to the ligand field strength of the axial ligands.

Polymer-Supported Optically Active fac(S)-Tris(thiotato)rhodium(III) Complex for Sulfur-Bridging Reaction With Precious Metal Ions.

PubMed

Aizawa, Sen-Ichi; Tsubosaka, Soshi

2016-01-01

The optically active mixed-ligand fac(S)-tris(thiolato)rhodium(III) complexes, ΔL -fac(S)-[Rh(aet)2 (L-cys-N,S)](-) (aet = 2-aminoethanethiolate, L-cys = L-cysteinate) () and ΔLL -fac(S)-[Rh(aet)(L-cys-N,S)2 ](2-) were newly prepared by the equatorial preference of the carboxyl group in the coordinated L-cys ligand. The amide formation reaction of with 1,10-diaminodecane and polyallylamine gave the diamine-bridged dinuclear Rh(III) complex and the single-chain polymer-supported Rh(III) complex with retention of the ΔL configuration of , respectively. These Rh(III) complexes reacted with Co(III) or Co(II) to give the linear-type trinuclear structure with the S-bridged Co(III) center and the two Δ-Rh(III) terminal moieties. The polymer-supported Rh(III) complex was applied not only to the CD spectropolarimetric detection and determination of a trace of precious metal ions such as Au(III), Pt(II), and Pd(II) but also to concentration and extraction of these metal ions into the solid polymer phase. Chirality 28:85-91, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Enzyme-like catalysis via ternary complex mechanism: alkoxy-bridged dinuclear cobalt complex mediates chemoselective O-esterification over N-amidation.

PubMed

Hayashi, Yukiko; Santoro, Stefano; Azuma, Yuki; Himo, Fahmi; Ohshima, Takashi; Mashima, Kazushi

2013-04-24

Hydroxy group-selective acylation in the presence of more nucleophilic amines was achieved using acetates of first-row late transition metals, such as Mn, Fe, Co, Cu, and Zn. Among them, cobalt(II) acetate was the best catalyst in terms of reactivity and selectivity. The combination of an octanuclear cobalt carboxylate cluster [Co4(OCOR)6O]2 (2a: R = CF3, 2b: R = CH3, 2c: R = (t)Bu) with nitrogen-containing ligands, such as 2,2'-bipyridine, provided an efficient catalytic system for transesterification, in which an alkoxide-bridged dinuclear complex, Co2(OCO(t)Bu)2(bpy)2(μ2-OCH2-C6H4-4-CH3)2 (10), was successfully isolated as a key intermediate. Kinetic studies and density functional theory calculations revealed Michaelis-Menten behavior of the complex 10 through an ordered ternary complex mechanism similar to dinuclear metallo-enzymes, suggesting the formation of alkoxides followed by coordination of the ester.

Pyrazole bridged dinuclear Cu(II) and Zn(II) complexes as phosphatase models: Synthesis and activity

NASA Astrophysics Data System (ADS)

Naik, Krishna; Nevrekar, Anupama; Kokare, Dhoolesh Gangaram; Kotian, Avinash; Kamat, Vinayak; Revankar, Vidyanand K.

2016-12-01

Present work describes synthesis of dibridged dinuclear [Cu2L2(μ2-NN pyr)(NO3)2(H2O)2] and [Zn2L(μ-OH)(μ-NNpyr)(H2O)2] complexes derived from a pyrazole based ligand bis(2-hydroxy-3-methoxybenzylidene)-1H-pyrazole-3,5-dicarbohydrazide. The ligand shows dimeric chelate behaviour towards copper against monomeric for zinc counterpart. Spectroscopic evidences affirm octahedral environment around the metal ions in solution state and non-electrolytic nature of the complexes. Both the complexes are active catalysts towards phosphomonoester hydrolysis with first order kcat values in the range of 2 × 10-3s-1. Zinc complex exhibited promising catalytic efficiency for the hydrolysis. The dinuclear complexes hydrolyse via Lewis acid activation, whereby the phosphate esters are preferentially bound in a bidentate bridging fashion and subsequent nucleophilic attack to release phosphate group.

Strong exchange and magnetic blocking in N₂³⁻-radical-bridged lanthanide complexes.

PubMed

Rinehart, Jeffrey D; Fang, Ming; Evans, William J; Long, Jeffrey R

2011-05-22

Single-molecule magnets approach the ultimate size limit for spin-based devices. These complexes can retain spin information over long periods of time at low temperature, suggesting possible applications in high-density information storage, quantum computing and spintronics. Notably, the success of most such applications hinges upon raising the inherent molecular spin-inversion barrier. Although recent advances have shown the viability of lanthanide-containing complexes in generating large barriers, weak or non-existent magnetic exchange coupling allows fast relaxation pathways that mitigate the full potential of these species. Here, we show that the diffuse spin of an N(2)(3-) radical bridge can lead to exceptionally strong magnetic exchange in dinuclear Ln(III) (Ln = Gd, Dy) complexes. The Gd(III) congener exhibits the strongest magnetic coupling yet observed for that ion, while incorporation of the high-anisotropy Dy(III) ion gives rise to a molecule with a record magnetic blocking temperature of 8.3 K at a sweep rate of 0.08 T s(-1).

E.S.R., magnetic, electronic and superoxide dismutase studies of imidazolate-bridged Cu(II)-Cu(II) complexes with ethylenediamine as capping ligand.

PubMed

Patel, R N; Singh, Nripendra; Shukla, K K; Gundla, V L N

2005-06-01

X-band E.S.R., magnetic and electronic spectra of some imidazolate-bridged homometallic complexes [(en)2Cu-R-Im-Cu(en)2](ClO4)3 where en, ethylenediamine; R-ImH, R = H imidazole (ImH); if R = CH3, 2-methylimidazole (M-ImH) and if R = C2H5, 2-ethylimidazole (E-ImH), and mononuclear complexes [(en)Cu-dien](ClO4)2 and [(en)Cu-PMDT](ClO4)2 where dien, diethylenetriamine; PMDT, pentamethyldiethylenetriamine have been described. Superoxide dismutase (SOD) activity has also been measured and compared with earlier reported complexes. In frozen solution at 77 K, the spectra show axial symmetry with a d(x2-y2) ground state. Difference in lambda(max) between mononuclear and binuclear complexes was found to be approximately 65-75 nm. Magnetic susceptibility and E.S.R. spectral measurements for all these binuclear complexes revealed that the copper(II) ions are involved in antiferromagnetic exchange interactions propagated by the imidazolate bridge.

Isolation of a new two-dimensional honeycomb carbonato-bridged copper(II) complex exhibiting long-range ferromagnetic ordering.

PubMed

Majumder, Arpi; Choudhury, Chirantan Roy; Mitra, Samiran; Rosair, Georgina M; El Fallah, M Salah; Ribas, Joan

2005-04-28

Atmospheric CO2 fixation by an aqueous solution containing Cu(ClO4)2.6H2O and 4-aminopyridine (4-apy) yields a novel example of a two-dimensional mu3-CO3 bridged copper(II) complex {[Cu(4-apy)2]3(mu3-CO3)2(ClO4)2.(1/2)CH3OH}n that has been characterized by IR, UV and X-ray crystallography; preliminary magnetic measurements show that complex exhibits long-range ordered ferromagnetic coupling.

Metal-metal interactions in tetrakis(diphenylphosphino)benzene-bridged dimetallic complexes and their related coordination polymers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Pei-Wei; Fox, M.A.

1994-06-22

Electrochemical, EPR, and spectroelectrochemical methods have been used to probe electronic coupling through a 1,2,4,5-tetrakis(diphenylphosphino)benzene bridging ligand connecting metal centers in several Ni-, Pd-, and Pt-containing dimetallic complexes. These dimetalated complexes showed weak intervalence charge transfer (IT) bands and slightly shifted redox potentials in comparison with their monometallic models. A Marcus-Hush analysis of the energies of the IT bands for the electrochemically generated mixed-valence heterodimetallic complexes (Ni{sup o}-Pd{sup II} and Ni{sup o}-Pt{sup II}, respectively) established the magnitude of intermetallic electronic coupling. The weak thermal coupling observed in these dimetalated complexes is consistent with the very low conductivities (10{sup {minus}8}-10{sup {minus}10}{omega}{supmore » -1} cm{sup {minus}1}) observed in the polymeric analogs of these complexes, namely, the newly prepared metal coordination polymers (M = Ni{sup II}, Pd{sup II}, Pt{sup II}) with 1,2,4,5-tetrakis(diphenylphosphino)benzene.« less

A new cadmium(II) complex with bridging dithiolate ligand: Synthesis, crystal structure and antifungal activity study

NASA Astrophysics Data System (ADS)

Singh, Mahesh Kumar; Sutradhar, Sanjit; Paul, Bijaya; Adhikari, Suman; Laskar, Folguni; Butcher, Raymond J.; Acharya, Sandeep; Das, Arijit

2017-07-01

A new polymeric complex of Cd(II) with 1,1-dicyanoethylene- 2,2-dithiolate [ i-MNT2- = {S2C:C(CN)2}2- ] as a bridging ligand has been synthesized and characterized on the basis of spectroscopy and single-crystal X-ray diffraction analysis. Single crystal X-ray diffraction analysis reveals that the Cadmium (II) complex is six coordinated 1D polymeric in nature. Biological screening effects in vitro of the synthesized polymeric complex has been tested against five fungi Synchitrium endobioticum, Pyricularia oryzae, Helminthosporium oryzae, Candida albicans(ATCC10231), Trichophyton mentagrophytes by the disc diffusion method. In vitro antifungal screening indicates that the complex exhibits fungistatic and fungicidal antifungal activity whereas K2i-MNT.H2O became silent on Synchitrium endobioticum, Pyricularia oryzae, Helminthosporium oryzae, Candida albicans (ATCC10231), Trichophyton mentagrophytes.

Cyanide-limited complexation of molybdenum(III): synthesis of octahedral [Mo(CN)(6)](3-) and cyano-bridged [Mo(2)(CN)(11)](5-).

PubMed

Beauvais, Laurance G; Long, Jeffrey R

2002-03-13

Octahedral coordination of molybdenum(III) is achieved by limiting the amount of cyanide available upon complex formation. Reaction of Mo(CF(3)SO(3))(3) with LiCN in DMF affords Li(3)[Mo(CN)(6)] x 6DMF (1), featuring the previously unknown octahedral complex [Mo(CN)(6)](3-). The complex exhibits a room-temperature moment of mu(eff) = 3.80 mu(B), and assignment of its absorption bands leads to the ligand field parameters Delta(o) = 24800 cm(-1) and B = 247 cm(-1). Further restricting the available cyanide in a reaction between Mo(CF(3)SO(3))(3) and (Et(4)N)CN in DMF, followed by recrystallization from DMF/MeOH, yields (Et(4)N)(5)[Mo(2)(CN)(11)] x 2DMF x 2MeOH (2). The dinuclear [Mo(2)(CN)(11)](5-) complex featured therein contains two octahedrally coordinated Mo(III) centers spanned by a bridging cyanide ligand. A fit to the magnetic susceptibility data for 2, gives J = -113 cm(-1) and g = 2.33, representing the strongest antiferromagnetic coupling yet observed through a cyanide bridge. Efforts to incorporate these new complexes in magnetic Prussian blue-type solids are ongoing.

A serials of sandwich-like trinuclear and one-dimensional chain cyanide-bridged iron(III)-copper(II) complexes: Syntheses, crystal structures and magnetic properties

NASA Astrophysics Data System (ADS)

Shi, Jingwen; Lan, Wenlong; Ren, Yanjie; Liu, Qingyun; Liu, Hui; Dong, Yunhui; Zhang, Daopeng

2018-04-01

Four pyridinecarboxamide trans-dicyanideiron(III) building blocks and one macrocyclic copper(II) compound have been employed to assemble cyanide-bridged heterometallic complexes, resulting in a serials of cyanide-bridged FeIII-CuII complexes with different structure types. The series of complexes can be formulated as: {[Cu(Cyclam)][Fe(bpb)(CN)2]2}·4H2O (1), {{[Cu(Cyclam)][Fe(bpb)(CN)2]}ClO4}n·nH2O (2), and {[Cu(Cyclam)][Fe(bpmb)(CN)2]2}·4H2O (3), {[Cu(Cyclam)][Fe(bpClb)(CN)2]2}·4H2O (4) and {{[Cu(Cyclam)][Fe(bpdmb)(CN)2]}ClO4}n·2nCH3OH (5) (bpb2- = 1,2-bis(pyridine-2-carboxamido)benzenate, bpmb2- = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate, bpClb2- = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate, bpdmb2- = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate, Cyclam = 1,4,8,11-tetraazacyclotetradecane). All the complexes have been characterized by elemental analysis, IR spectra and structural determination. Single X-ray diffraction analysis shows the similar neutral sandwich-like structures for complexes 1, 3 and 4, in which the two cyano precursors acting as monodentate ligand through one of their two cyanide groups were coordinated face to face to central Cu(II) ion. The complexes 2 and 5 can be structurally characterized as one-dimensional cationic single chain consisting of alternating units of [Cu(Cyclam)]2+ and [Fe(bpb/bpdmb)(CN)2]- with free ClO4- as balanced anion. Investigation over magnetic properties of the whole serials of complexes reveals the antiferromagnetic magnetic coupling between the neighboring cyanide-bridged Fe(III) and Cu(II) ions in complexes 3 and 4 and the ferromagnetic interaction in complexes 1, 2 and 5, respectively.

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

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

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

Polynuclear Hydroxido-Bridged Complexes of Platinum(IV) with Terminal Nitrato Ligands.

PubMed

Vasilchenko, Danila; Berdugin, Semen; Tkachev, Sergey; Baidina, Iraida; Romanenko, Galina; Gerasko, Olga; Korenev, Sergey

2015-05-18

For the first time the polynuclear hydroxido-bridged platinum(IV) nitrato complexes with nuclearity higher than two were isolated from nitric acid solutions of [Pt(H2O)2(OH)4] and crystallized as supramolecular compounds of macrocyclic cavitands cucurbit[n]uril (CB[n], n = 6,8) and 18-crown-6 ether: [Pt4(μ3-OH)2(μ2-OH)4(NO3)10]·CB[6]·25H2O (I), [Pt6(μ3-OH)4(μ2-OH)6(NO3)12](NO3)2·CB[8]·50H2O (II), and [H3O⊂18-crown-6]2[Pt2(μ2-OH)2(NO3)8][Pt4(μ3-OH)2(μ2-OH)4(NO3)10] (III). The isolation of the compounds in the single crystalline state allows the determination of the structure of the tetranuclear and hexanuclear complexes [Pt4(μ3-OH)2(μ2-OH)4(NO3)10] and [Pt6(μ3-OH)4(μ2-OH)6(NO3)12](2+), which have been previously unknown in the solid state. Stability of Ptx(OH)y cores of the polynuclear nitrato complexes toward alkaline hydrolysis was verified by (195)Pt NMR spectroscopy. Analysis of (195)Pt NMR spectra of the compound III reveals that addition of every Pt(μ-OH)2Pt ring results in ∼260 ppm downfield shift relative to the mononuclear form, which allows the prediction of signal positions for complexes of higher nuclearity.

Synthesis, characterization, X-ray crystal structure and conductometry studying of a number of new Schiff base complexes; a new example of binuclear square pyramidal geometry of Cu(II) complex bridged with an oxo group

NASA Astrophysics Data System (ADS)

Golbedaghi, Reza; Alavipour, Ehsan

2015-11-01

Three new binuclear Cu(II), Mn(II), Co(II) complexes [Cu2(L) (ClO4)](ClO4)2 (1), [Mn2(L) (ClO4)](ClO4)2 (2), and [Co2(L) (ClO4)](ClO4)2 (3), {L = 1,3-bis(2-((Z)-(2-aminopropylimino)methyl)phenoxy)propan-2-ol} have been synthesized. Single crystal X-ray structure analysis of complex 1 showed that the complex is binuclear and all nitrogen and oxygen atoms of ligand (N4O3) are coordinated to two Cu(II) center ions. In addition, the crystal structure studying shows, a perchlorate ion has been bridged to the Cu(II) metal centers. However, two distorted square pyramidal Cu(II) ions are bridged asymmetrically by a perchlorate ion and oxygen of hydroxyl group of Schiff base ligand. In addition, the conductometry behaviors of all complexes were studied in acetonitrile solution.

Synthesis and Study of Metallonitride Complexes and Polymers

DTIC Science & Technology

1992-03-02

heterobimetallic nitride-bridged complexes, examples of homobimetallic nitride-bridged complexes, and new linear chain metallonitride polymers. We...the Nitride Bridge. Synthesis and Reactivity of Early-Late Heterobimetallic Nitride-Bridged Complexes," C. M. Jones, D. M.-T. Chan, J. C. Calabrese

[μ-Bis(diphenyl­phosphan­yl)methane]­tricarbon­yl(μ-p-toluene­sulfonyl­meth­yl isocyanato)(triphenyl­phosphane)ironplatinum(Fe—Pt)

PubMed Central

Jourdain, Isabelle; Knorr, Michael; Koller, Stephan G.; Strohmann, Carsten

2012-01-01

The title compound, [FePt(C9H9NO2S)(C18H15P)(C25H22P2)(CO)3], represents a rare example of an isonitrile-bridged heterobimetallic complex (here Pt and Fe) and is an inter­esting precursor for the preparation of heterodinuclear μ-amino­carbyne complexes, since the basic imine-type N atom of the μ2-C=N–R ligand readily undergoes addition with various electrophiles to afford iminium-like salts. In the crystal, the almost symmetrically bridging μ2-C=N-R ligand (neglecting the different atomic radii of Fe and Pt) is strongly bent towards the Fe(CO)3 fragment, with a C=N-R angle of only 121.1 (4)°. PMID:22412466

Photocrystallographic observation of halide-bridged intermediates in halogen photoeliminations.

PubMed

Powers, David C; Anderson, Bryce L; Hwang, Seung Jun; Powers, Tamara M; Pérez, Lisa M; Hall, Michael B; Zheng, Shao-Liang; Chen, Yu-Sheng; Nocera, Daniel G

2014-10-29

Polynuclear transition metal complexes, which frequently constitute the active sites of both biological and chemical catalysts, provide access to unique chemical transformations that are derived from metal-metal cooperation. Reductive elimination via ligand-bridged binuclear intermediates from bimetallic cores is one mechanism by which metals may cooperate during catalysis. We have established families of Rh2 complexes that participate in HX-splitting photocatalysis in which metal-metal cooperation is credited with the ability to achieve multielectron photochemical reactions in preference to single-electron transformations. Nanosecond-resolved transient absorption spectroscopy, steady-state photocrystallography, and computational modeling have allowed direct observation and characterization of Cl-bridged intermediates (intramolecular analogues of classical ligand-bridged intermediates in binuclear eliminations) in halogen elimination reactions. On the basis of these observations, a new class of Rh2 complexes, supported by CO ligands, has been prepared, allowing for the isolation and independent characterization of the proposed halide-bridged intermediates. Direct observation of halide-bridged structures establishes binuclear reductive elimination as a viable mechanism for photogenerating energetic bonds.

Neuroarchitecture and neuroanatomy of the Drosophila central complex: A GAL4-based dissection of protocerebral bridge neurons and circuits.

PubMed

Wolff, Tanya; Iyer, Nirmala A; Rubin, Gerald M

2015-05-01

Insects exhibit an elaborate repertoire of behaviors in response to environmental stimuli. The central complex plays a key role in combining various modalities of sensory information with an insect's internal state and past experience to select appropriate responses. Progress has been made in understanding the broad spectrum of outputs from the central complex neuropils and circuits involved in numerous behaviors. Many resident neurons have also been identified. However, the specific roles of these intricate structures and the functional connections between them remain largely obscure. Significant gains rely on obtaining a comprehensive catalog of the neurons and associated GAL4 lines that arborize within these brain regions, and on mapping neuronal pathways connecting these structures. To this end, small populations of neurons in the Drosophila melanogaster central complex were stochastically labeled using the multicolor flip-out technique and a catalog was created of the neurons, their morphologies, trajectories, relative arrangements, and corresponding GAL4 lines. This report focuses on one structure of the central complex, the protocerebral bridge, and identifies just 17 morphologically distinct cell types that arborize in this structure. This work also provides new insights into the anatomical structure of the four components of the central complex and its accessory neuropils. Most strikingly, we found that the protocerebral bridge contains 18 glomeruli, not 16, as previously believed. Revised wiring diagrams that take into account this updated architectural design are presented. This updated map of the Drosophila central complex will facilitate a deeper behavioral and physiological dissection of this sophisticated set of structures. © 2014 Wiley Periodicals, Inc.

Study of the influence of the bridge on the magnetic coupling in cobalt(II) complexes.

PubMed

Fabelo, Oscar; Cañadillas-Delgado, Laura; Pasán, Jorge; Delgado, Fernando S; Lloret, Francesc; Cano, Joan; Julve, Miguel; Ruiz-Pérez, Catalina

2009-12-07

Two new cobalt(II) complexes of formula [Co(2)(bta)(H(2)O)(6)](n) x 2nH(2)O (1) and [Co(phda)(H(2)O)](n) x nH(2)O (2) [H(4)bta = 1,2,4,5-benzenetetracarboxylic acid, H(2)phda = 1,4-phenylenediacetic acid] have been characterized by single crystal X-ray diffraction. Compound 1 is a one-dimensional compound where the bta(4-) ligand acts as 2-fold connector between the cobalt(II) ions through two carboxylate groups in para-conformation. Triply bridged dicobalt(II) units occur within each chain, a water molecule, a carboxylate group in the syn-syn conformation, and an oxo-carboxylate with the mu(2)O(1);kappa(2)O(1),O(2) coordination mode acting as bridges. Compound 2 is a three-dimensional compound, where the phda(2-) group acts as a bridge through its two carboxylate groups, one of them adopting the mu-O,O' coordination mode in the syn-syn conformation and the other exhibiting the single mu(2)-O'' bridging mode. As in 1, chains of cobalt(II) ions occur in 2 with a water molecule, a syn-syn carboxylate group, and an oxo-carboxylate constitute the triply intrachain bridging skeleton. Each chain is linked to other four ones through the phda(2-) ligand, giving rise to the three-dimensional structure. The values of the intrachain cobalt-cobalt separation are 3.1691(4) (1) and 3.11499(2) A (2) whereas those across the phenyl ring of the extended bta(4-) (1) and phda(2-) (2) groups are 10.1120(6) and 11.4805(69 A, respectively. The magnetic properties of 1 and 2 have been investigated in the temperature range 1.9-300 K, and their analysis has revealed the occurrence of moderate intrachain ferromagnetic couplings [J = +5.4 (1) and +2.16 cm(-1) (2), J being the isotropic magnetic coupling parameter], the magnetic coupling through the extended bta(4-) and phda(2-) with cobalt-cobalt separations larger than 10 A being negligible. The nature and magnitude of the magnetic interactions between the high-spin cobalt(II) ions in 1 and 2 are compared to those of related systems and

A novel tridentate coordination mode for the carbonatonickel system exhibited in an unusual hexanuclear nickel(II) mu3-carbonato-bridged complex.

PubMed

Anderson, James C; Blake, Alexander J; Moreno, Rafael Bou; Raynel, Guillaume; van Slageren, Joris

2009-11-14

The fixation of CO(2) at ambient temperature has been achieved by the reaction of Ni(cod)(2) and TMEDA in CO(2) saturated THF that yields a novel hexanuclear nickel(II) mu(3)-carbonato bridged complex [Ni(6)(mu(3)-CO(3))(4)(TMEDA)(6)(H(2)O)(12)](OH)(4) in 59% yield. The complex was characterised by MS analysis and the structure corroborated by single-crystal X-ray crystallography. The complex exhibits a rare carbonato binding mode for Ni(II) complexes and moderately strong antiferromagnetic interactions.

Intramolecular ferro- and antiferromagnetic interactions in oxo-carboxylate bridged digadolinium(III) complexes.

PubMed

Cañadillas-Delgado, Laura; Fabelo, Oscar; Pasán, Jorge; Delgado, Fernando S; Lloret, Francesc; Julve, Miguel; Ruiz-Pérez, Catalina

2010-08-21

Two new digadolinium(III) complexes with monocarboxylate ligands, [Gd2(pac)6(H2O)4] (1) and [Gd2(tpac)6(H2O)4] (2) (Hpac = pentanoic acid and Htpac = 3-thiopheneacetic acid), have been prepared and their structures determined by X-ray diffraction on single crystals. Their structures consist of neutral and isolated digadolinium(III) units, containing six monocarboxylate ligands and four coordinated water molecules, the bridging skeleton being built by a muO(1):kappa2O(1)O(2) framework. This structural pattern has already been observed in the parent acetate-containing compound [Gd2(ac)6(H2O)4] x 4 H2O (3) whose structure and magnetic properties were reported elsewhere (L. Cañadillas-Delgado, O. Fabelo, J. Cano, J. Pasán, F. S. Delgado, M. Julve, F. Lloret and C. Ruiz-Pérez, CrystEngComm, 2009, 11, 2131). Each gadolinium(III) ion in 1 and 2 is nine-coordinated with seven carboxylate-oxygen atoms from four pac (1)/tpac (2) ligands and two water molecules (1 and 2) building a distorted monocapped square antiprism. The values of the intramolecular gadolinium-gadolinium separation are 4.1215(5) (1), 4.1255(6) (2) and 4.1589(3) A (3) and those of the angle at the oxo-carboxylate bridge (theta) are 113.16(13) (1), 112.5(2) (2) and 115.47(7) degrees (3). Magnetic susceptibility measurements in the temperature range 1.9-300 K reveal the occurrence of a weak intramolecular antiferromagnetic interaction [J = -0.032(1) (1) and -0.012(1) cm(-1) (2), the Hamiltonian being defined as H = -JS(A) x S(B)] in contrast with the intramolecular ferromagnetic coupling which occurs in 3 (J = +0.031(1) cm(-1)). The magneto-structural data of 1-3 show the relevance of the geometrical parameters at the muO(1):kappa2O(1)O(2) bridge on the nature of the magnetic coupling between two gadolinium(III) ions.

Mononuclear thiocyanate containing nickel(II) and binuclear azido bridged nickel(II) complexes of N4-coordinate pyrazole based ligand: Syntheses, structures and magnetic properties

NASA Astrophysics Data System (ADS)

Solanki, Ankita; Monfort, Montserrat; Kumar, Sujit Baran

2013-10-01

Two mononuclear nickel(II) complexes [NiL1(NCS)2] (1) and [NiL2(NCS)2] (2) and two azido bridged binuclear nickel(II) complexes [Ni(()2()2] (3) and [Ni(()2()2] (4), where L1, L2, L1‧ and L2‧ are N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1), N,N-bis((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2), N,N-diethyl-N‧-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1‧) and N-((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2‧) have been synthesized and characterized by microanalyses and physico-chemical methods. Single crystal X-ray diffraction analyses revealed that complexes 1 and 2 are mononuclear NCS- containing Ni(II) complex with octahedral geometry and complexes 3 and 4 are end-on (μ-1,1) azido bridged binuclear Ni(II) complexes with distorted octahedral geometry. Variable temperature magnetic studies of the complexes 3 and 4 display ferromagnetic interaction with J values 19 and 32 cm-1, respectively.

Resonant tunneling via a Ru-dye complex using a nanoparticle bridge junction.

PubMed

Nishijima, Satoshi; Otsuka, Yoichi; Ohoyama, Hiroshi; Kajimoto, Kentaro; Araki, Kento; Matsumoto, Takuya

2018-06-15

Nonlinear current-voltage (I-V) characteristics is an important property for the realization of information processing in molecular electronics. We studied the electrical conduction through a Ru-dye complex (N-719) on a 2-aminoethanethiol (2-AET) monolayer in a nanoparticle bridge junction system. The nonlinear I-V characteristics exhibited a threshold voltage at around 1.2 V and little temperature dependence. From the calculation of the molecular states using density functional theory and the energy alignment between the electrodes and molecules, the conduction mechanism in this system was considered to be resonant tunneling via the HOMO level of N-719. Our results indicate that the weak electronic coupling of electrodes and molecules is essential for obtaining nonlinear I-V characteristics with a clear threshold voltage that reflect the intrinsic molecular state.

Resonant tunneling via a Ru–dye complex using a nanoparticle bridge junction

NASA Astrophysics Data System (ADS)

Nishijima, Satoshi; Otsuka, Yoichi; Ohoyama, Hiroshi; Kajimoto, Kentaro; Araki, Kento; Matsumoto, Takuya

2018-06-01

Nonlinear current–voltage (I–V) characteristics is an important property for the realization of information processing in molecular electronics. We studied the electrical conduction through a Ru–dye complex (N-719) on a 2-aminoethanethiol (2-AET) monolayer in a nanoparticle bridge junction system. The nonlinear I–V characteristics exhibited a threshold voltage at around 1.2 V and little temperature dependence. From the calculation of the molecular states using density functional theory and the energy alignment between the electrodes and molecules, the conduction mechanism in this system was considered to be resonant tunneling via the HOMO level of N-719. Our results indicate that the weak electronic coupling of electrodes and molecules is essential for obtaining nonlinear I–V characteristics with a clear threshold voltage that reflect the intrinsic molecular state.

Neuroarchitecture and neuroanatomy of the Drosophila central complex: A GAL4-based dissection of protocerebral bridge neurons and circuits

PubMed Central

Wolff, Tanya; Iyer, Nirmala A; Rubin, Gerald M

2015-01-01

Insects exhibit an elaborate repertoire of behaviors in response to environmental stimuli. The central complex plays a key role in combining various modalities of sensory information with an insect's internal state and past experience to select appropriate responses. Progress has been made in understanding the broad spectrum of outputs from the central complex neuropils and circuits involved in numerous behaviors. Many resident neurons have also been identified. However, the specific roles of these intricate structures and the functional connections between them remain largely obscure. Significant gains rely on obtaining a comprehensive catalog of the neurons and associated GAL4 lines that arborize within these brain regions, and on mapping neuronal pathways connecting these structures. To this end, small populations of neurons in the Drosophila melanogaster central complex were stochastically labeled using the multicolor flip-out technique and a catalog was created of the neurons, their morphologies, trajectories, relative arrangements, and corresponding GAL4 lines. This report focuses on one structure of the central complex, the protocerebral bridge, and identifies just 17 morphologically distinct cell types that arborize in this structure. This work also provides new insights into the anatomical structure of the four components of the central complex and its accessory neuropils. Most strikingly, we found that the protocerebral bridge contains 18 glomeruli, not 16, as previously believed. Revised wiring diagrams that take into account this updated architectural design are presented. This updated map of the Drosophila central complex will facilitate a deeper behavioral and physiological dissection of this sophisticated set of structures. J. Comp. Neurol. 523:997–1037, 2015. © 2014 Wiley Periodicals, Inc. PMID:25380328

Evaluation of fleet management techniques for timber highway bridges

Treesearch

Brent M. Phares; Travis K. Hosteng; Justin Dahlberg; Michael A. Ritter

2011-01-01

The general condition of the nation's bridges presents a complex management issue when considering cost, safety, and time. Consequently, the management of those bridges can become an overwhelming task. The need for a management system that is specific to rural systems may help to improve the management of this significant number of bridges. Although individual...

Investigating vibrational anharmonic couplings in cyanide-bridged transition metal mixed valence complexes using two-dimensional infrared spectroscopy.

PubMed

Slenkamp, Karla M; Lynch, Michael S; Van Kuiken, Benjamin E; Brookes, Jennifer F; Bannan, Caitlin C; Daifuku, Stephanie L; Khalil, Munira

2014-02-28

Using polarization-selective two-dimensional infrared (2D IR) spectroscopy, we measure anharmonic couplings and angles between the transition dipole moments of the four cyanide stretching (νCN) vibrations found in [(NH3)5Ru(III)NCFe(II)(CN)5](-) (FeRu) dissolved in D2O and formamide and [(NC)5Fe(II)CNPt(IV)(NH3)4NCFe(II)(CN)5](4-) (FePtFe) dissolved in D2O. These cyanide-bridged transition metal complexes serve as model systems for studying the role of high frequency vibrational modes in ultrafast photoinduced charge transfer reactions. Here, we focus on the spectroscopy of the νCN modes in the electronic ground state. The FTIR spectra of the νCN modes of the bimetallic and trimetallic systems are strikingly different in terms of frequencies, amplitudes, and lineshapes. The experimental 2D IR spectra of FeRu and FePtFe and their fits reveal a set of weakly coupled anharmonic νCN modes. The vibrational mode anharmonicities of the individual νCN modes range from 14 to 28 cm(-1). The mixed-mode anharmonicities range from 2 to 14 cm(-1). In general, the bridging νCN mode is most weakly coupled to the radial νCN mode, which involves the terminal CN ligands. Measurement of the relative transition dipole moments of the four νCN modes reveal that the FeRu molecule is almost linear in solution when dissolved in formamide, but it assumes a bent geometry when dissolved in D2O. The νCN modes are modelled as bilinearly coupled anharmonic oscillators with an average coupling constant of 6 cm(-1). This study elucidates the role of the solvent in modulating the molecular geometry and the anharmonic vibrational couplings between the νCN modes in cyanide-bridged transition metal mixed valence complexes.

A dithiolate-bridged (CN)2(CO)Fe-Ni complex reproducing the IR bands of [NiFe] hydrogenase.

PubMed

Tanino, Soichiro; Li, Zilong; Ohki, Yasuhiro; Tatsumi, Kazuyuki

2009-03-16

A dithiolate-bridged dinuclear Fe-Ni complex, which has the desired fac-(CN)(2)(CO) ligand set at iron, has been synthesized. Its CN/CO bands in the IR spectrum reproduce those of the Ni-A, Ni-B, and Ni-SU states, which indicate that these octahedral Fe(II) centers have similar electronic properties. This result verifies the assignment of a (CN)(2)(CO)Fe(II) moiety in the active site of [NiFe] hydrogenase.

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

PubMed

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

Wright-Fisher diffusion bridges.

PubMed

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.

Bifunctional Zn(II)Ln(III) dinuclear complexes combining field induced SMM behavior and luminescence: enhanced NIR lanthanide emission by 9-anthracene carboxylate bridging ligands.

PubMed

Palacios, María A; Titos-Padilla, Silvia; Ruiz, José; Herrera, Juan Manuel; Pope, Simon J A; Brechin, Euan K; Colacio, Enrique

2014-02-03

There were new dinuclear Zn(II)-Ln(III) complexes of general formulas [Zn(μ-L)(μ-OAc)Ln(NO3)2] (Ln(III) = Tb (1), Dy (2), Er (3), and Yb (4)), [Zn(μ-L)(μ-NO3)Er(NO3)2] (5), [Zn(H2O)(μ-L)Nd(NO3)3]·2CH3OH (6), [Zn(μ-L)(μ-9-An)Ln(NO3)2]·2CH3CN (Ln(III) = Tb (7), Dy (8), Er (9), Yb(10)), [Zn(μ-L)(μ-9-An)Yb(9-An)(NO3)3]·3CH3CN (11), [Zn(μ-L)(μ-9-An)Nd(9-An)(NO3)3]·2CH3CN·3H2O (12), and [Zn(μ-L)(μ-9-An)Nd(CH3OH)2(NO3)]ClO4·2CH3OH (13) prepared from the reaction of the compartmental ligand N,N',N″-trimethyl-N,N″-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine (H2L), with ZnX2·nH2O (X = NO3(-) or OAc(-)) salts, Ln(NO3)3·nH2O, and, in some instances, 9-anthracenecarboxylate anion (9-An). In all these complexes, the Zn(II) ions invariably occupy the internal N3O2 site whereas the Ln(III) ions show preference for the O4 external site, giving rise to a Zn(μ-diphenoxo)Ln bridging fragment. Depending on the Zn(II) salt and solvent used in the reaction, a third bridge can connect the Zn(II) and Ln(III) metal ions, giving rise to triple-bridged diphenoxoacetate in complexes 1-4, diphenoxonitrate in complex 5, and diphenoxo(9-anthracenecarboxylate) in complexes 8-13. Dy(III) and Er(III) complexes 2, 8 and 3, 5, respectively, exhibit field induced single molecule magnet (SMM) behavior, with Ueff values ranging from 11.7 (3) to 41(2) K. Additionally, the solid-state photophysical properties of these complexes are presented showing that ligand L(2-) is able to sensitize Tb(III)- and Dy(III)-based luminescence in the visible region through an energy transfer process (antenna effect). The efficiency of this process is much lower when NIR emitters such as Er(III), Nd(III), and Yb(III) are considered. When the luminophore 9-anthracene carboxylate is incorporated into these complexes, the NIR luminescence is enhanced which proves the efficiency of this bridging ligand to act as antenna group. Complexes 2, 3, 5, and 8 can be considered as dual materials

Luminescence, electrochemistry and host-guest properties of dinuclear platinum(ii) terpyridyl complexes of sulfur-containing bridging ligands.

PubMed

Tang, Rowena Pui-Ling; Wong, Keith Man-Chung; Zhu, Nianyong; Yam, Vivian Wing-Wah

2009-05-28

A series of dinuclear platinum(ii) terpyridyl and terpyridyl-crown complexes with 2,2-dicyano-1,1-ethylenedithiolate (i-mnt), 1,3-benzenedithiolate (SC(6)H(4)S-1,3) and N,N-diethyldithiocarbamate (dtc) bridging ligands have been synthesized and characterized. Their photophysical and electrochemical properties, together with that of the related mononuclear platinum(ii) terpyridyl-crown complex and its crown-free analogue, have been studied. The ion-binding properties of the terpyridyl-crown complexes have been determined by electronic absorption spectroscopy and ESI-mass spectrometry. The X-ray crystal structures of [Pt(trpyC[triple bond, length as m-dash]C-benzo-15-crown-5)Cl]PF(6), [{Pt(trpy)}(2)(micro-SC(6)H(4)S-1,3)](PF(6))(2) and [{Pt(trpy)}(2){micro-(i-mnt)}](PF(6))(2) have also been determined.

Long-term maintenance monitoring demonstration on a movable bridge.

DOT National Transportation Integrated Search

2011-09-30

The maintenance costs related to movable bridges are considerably higher than those of fixed bridges, mostly : because of the complex interaction of the mechanical, electrical and structural components. A malfunction of any : component can cause an u...

Earthquake fragility assessment of curved and skewed bridges in Mountain West region.

DOT National Transportation Integrated Search

2016-09-01

Reinforced concrete (RC) bridges with both skew and curvature are common in areas with : complex terrains. Skewed and/or curved bridges were found in existing studies to exhibit more : complicated seismic performance than straight bridges, however th...

Salt bridges: geometrically specific, designable interactions.

PubMed

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.

Modeling Security Bridge Certificate Authority Architecture

NASA Astrophysics Data System (ADS)

Ren, Yizhi; Li, Mingchu; Sakurai, Kouichi

Current Public Key Infrastructures suffer from a scaling problem, and some may have security problems, even given the topological simplification of bridge certification authorities. This paper analyzes the security problems in Bridge Certificate Authorities (BCA) model by using the concept of “impersonation risk, ” and proposes a new modified BCA model, which enhances its security, but is a bit more complex incertification path building and implementation than the existing one.

Copper(II) cyanido-bridged bimetallic nitroprusside-based complexes: Syntheses, X-ray structures, magnetic properties, {sup 57}Fe Moessbauer spectroscopy and thermal studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Travnicek, Zdenek, E-mail: zdenek.travnicek@upol.c; Herchel, Radovan; Mikulik, Jiri

2010-05-15

Three heterobimetallic cyanido-bridged copper(II) nitroprusside-based complexes of the compositions [Cu(tet)Fe(CN){sub 5}NO].H{sub 2}O (1), where tet=N,N'-bis(3-aminopropyl)ethylenediamine, [Cu(hto)Fe(CN){sub 5}NO].2H{sub 2}O (2), where hto=1,3,6,9,11,14-hexaazatricyclo[12.2.1.1{sup 6,9}]octadecane and [Cu(nme){sub 2}Fe(CN){sub 5}NO].H{sub 2}O (3), where nme=N-methylethylenediamine, were synthesized and characterized by elemental analyses, {sup 57}Fe Moessbauer and FTIR spectroscopies, thermal analysis, magnetic measurements and single-crystal X-ray analysis. The products of thermal degradation processes of 2 and 3 were studied by XRD, {sup 57}Fe Moessbauer spectroscopy, SEM and EDS, and they were identified as mixtures of CuFe{sub 2}O{sub 4} and CuO. - Three heterobimetallic cyano-bridged copper(II) nitroprusside-based complexes of the general compositions of [Cu(L)Fe(CN){sub 5}NO].xH{sub 2}O, wheremore » L=N,N'-bis(3-aminopropyl)ethylenediamine (complex 1), 1,3,6,9,11,14-hexaazatricyclo[12.2.1.1{sup 6,9}]-octadecane (complex 2) and N-methylethylenediamine (complex 3), were synthesized, and fully structurally and magnetically characterized. SEM, EDS, XRD and {sup 57}Fe Moessbauer experiments were used for characterization of thermal decomposition products of complexes 2 and 3.« less

Nucleophilic ring opening of bridging thietane ligands in trirhenium carbonyl cluster complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, R.D.; Cortopassi, J.E.; Falloon, S.B.

1992-11-01

The reactions of 3,3-dimethylthietane, SCH{sub 2}CMe{sub 2}CH{sub 2} (3,3-DMT), and thietane, SCH{sub 2}CH{sub 2}CH{sub 2}, with Re{sub 3}(CO){sub 10}[{mu}-SCH{sub 2}CH{sub 2}CH{sub 2}]({mu}-H){sub 3}, 2b. Compound 2a was characterized crystallographically and was found to consist of a trirhenium cluster with three bridging hydride ligands and a bridging thietane ligand coordinated through its sulfur atom. 2a and 2b react with halide ions by ring-opening additions to the 3,3-DMT ligand to yield the complex anions [Re{sub 3}(CO){sub 10}({mu}-SCH{sub 2}CMe{sub 2}CH{sub 2}x)({mu}-h){sub 3}]{sup -} 3A-6A, X = F (71%), Cl(71%), Br(84%), I(87%) and [Re{sub 3}(CO){sub 10}({mu}-SCH{sub 2}CH{sub 2}CH{sub 2}Cl)({mu}-H){sub 3}]{sup -}, 4b (67%). Similarly,more » addition of NMe{sub 3} to 2a and 2b yielded the ring-opened zwitterions Re{sub 3}(CO){sub 10}({mu}-SCH{sub 2}CMe{sub 2}CH{sub 2}NMe{sub 3})({mu}-H){sub 3}, 7 a crystographically. They are zwitterions positively charged at the nitrogen atoms and negatively charged on the trirhenium clusters. Complex 7b was also obtained in a 48% yield from the reaction of Re{sub 3}(C){sub 12}({mu}-H){sub 3} with Me{sub 3}NO in the presence of thietane, but the corresponding reaction using 3,3-DMT yielded only 2a and Re{sub 3}(CO){sub 11}(SCH{sub 2}CMe{sub 2}CH{sub 2})({mu}-H){sub 3}, 8. Attempts to obtain a ring-opening addition to 2a by reaction with PMe{sub 2}Ph yielded only Re{sub 3}(CO){sub 10}(PMe{sub 2}PH){sub 2}({mu}-H){sub 3} by ligand substitution. Attempts to obtain ring opening addition to 8 by reaction with I{sup -} yielded only [Re{sub 3}(CO){sub 11}I({mu}-H){sub 3}]{sup -} by ligand substitution. 20 refs., 3 figs., 10 tabs.« less

Three tier transition of Neoarchean TTG-sanukitoid magmatism in the Beit Bridge Complex, Southern Africa

NASA Astrophysics Data System (ADS)

Rajesh, H. M.; Belyanin, G. A.; Van Reenen, D. D.

2018-01-01

Neoarchean TTG-sanukitoid associations of contrasting scales occur within the Beit Bridge Complex terrane of the Limpopo Complex in southern Africa. These include the smaller 2.65-2.63 Ga Avoca granitoid and the voluminous 2.73-2.64 Ga Alldays granitoid. This study characterizes the wide compositional spectrum preserved in these two granitoids. The elliptical Avoca pluton consists of a biotite-amphibole-orthopyroxene ± clinopyroxene-bearing core that is dominantly trondhjemite with less dominant tonalite and granodiorite variants, and a thin amphibole-biotite-bearing granite rim, with local occurrence of two-pyroxene-bearing metabasite boudins. While both the core and rim rocks exhibit a linear fabric, the granite in addition preserves a penetrative foliation. Field relations of granite enclaves in the core rocks together with available ages indicate that the core rocks intruded the granite. The foliated biotite ± amphibole-bearing Alldays granitoid contains inclusions of older supracrustals and rocks of the Messina layered intrusion, and is widely distributed. Compositionally, it include tonalites and granodiorites and to a lesser extent trondhjemites. Both the Avoca core and rim rocks are characterized by difference in mineral chemistry, with the mafic minerals Mg-rich in the TTG core, while they are Fe-rich in the granite and metabasite. In comparison, biotite is Mg-rich and amphibole is Fe-rich in the Alldays granitoid. Two groups of Alldays TTG can be delineated in terms of whole-rock geochemical characteristics, and are comparable to the low- to medium-pressure TTG groups delineated by Moyen (2011), while the Avoca TTG is similar to the high-pressure TTG group. The lowest silica samples from each group of granitoid have geochemical characteristics comparable to Archean sanukitoids, with those from the Avoca granitoid similar to low-Ti sanukitoids, and those from the Alldays granitoid similar to low-Ti and high-Ti sanukitoids. Separate petrogenetic models

A binuclear Mn(III) complex of a scorpiand-like ligand displaying a single unsupported Mn(III)-O-Mn(III) bridge.

PubMed

Blasco, Salvador; Cano, Joan; Clares, M Paz; García-Granda, Santiago; Doménech, Antonio; Jiménez, Hermas R; Verdejo, Begoña; Lloret, Francesc; García-España, Enrique

2012-11-05

The crystal structure of a binuclear Mn(III) complex of a scorpiand-like ligand (L) displays an unsupported single oxo bridging ligand with a Mn(III)-O-Mn(III) angle of 174.7°. Magnetic susceptibility measurements indicate strong antiferromagnetic coupling between the two metal centers. DFT calculations have been carried out to understand the magnetic behavior and to analyze the nature of the observed Jahn-Teller distortion. Paramagnetic (1)H NMR has been applied to rationalize the formation and magnetic features of the complexes formed in solution.

Electrochemical variational study of donor/acceptor orbital mixing and electronic coupling in cyanide-bridged mixed-valence complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Yuhuua; Hupp, J.T.

1992-07-08

Cyanide-bridged mixed-valence complexes are interesting examples of strongly covalently linked redox systems which, nevertheless, exist in valence-localized form. As mixed-valence species, they display fairly intense intervalence (or metal-to-metal) charge-transfer transitions ([epsilon] [approx] 3000 M[sup [minus]1] cm[sup [minus]1]), which tend to be shifted toward the visible region from the near-infrared on account of substantial redox asymmetry. The authors have recently succeeded in obtaining (by femtosecond transient absorbance spectroscopy) a direct measure of the thermal kinetics (k[sub ET]) of the highly exothermic back-electron-transfer reaction which follows intervalence excitation in one of these complexes, (H[sub 3]N)[sub 5]Ru-NC-Fe(CN)[sub 5][sup [minus

Synthesis, spectroscopic, thermal and structural properties of [M(3-aminopyridine)2Ni(μ-CN)2(CN)2]n (M(II) = Co and Cu) heteropolynuclear cyano-bridged complexes

NASA Astrophysics Data System (ADS)

Kartal, Zeki

2016-01-01

Two novel cyano-bridged heteropolynuclear complexes, [Co(3-aminopyridine)2Ni(μ-CN)2(CN)2]n and [Cu(3-aminopyridine)2Ni(μ-CN)2(CN)2]n have been synthesized and characterized by elemental, thermal, FT-IR and FT-Raman spectroscopies. The structures of complexes have been determined by X-ray powder diffraction. The FT-IR and FT-Raman spectra of complexes have been recorded in the region of 3500-400 cm-1 and 3500-100 cm-1, respectively. General information was acquired about structural properties of these complexes from FT-IR and FT-Raman spectra by considering changes at characteristic peaks of the cyano group and 3AP. The splitting of the ν(Ctbnd N) stretching bands in the FT-IR spectra for complexes indicates the presence of terminal and bridging cyanides. The thermal behaviors of these complexes have been also investigated in the range of 25-950 °C using TG and DTG methods. Magnetic susceptibility measurements were made at room temperature using Gouy-balance.

Cost and Ecological Feasibility of using UHPC in Highway Bridges

DOT National Transportation Integrated Search

2017-11-15

There is a growing interest in expanding the use of Ultra-high performance concrete (UHPC) from bridge deck joints for accelerated bridge construction to complex architectural and advanced structural applications. The high costs currently associated ...

Bridge Condition Assessment Using D Numbers

PubMed Central

Hu, Yong

2014-01-01

Bridge condition assessment is a complex problem influenced by many factors. The uncertain environment increases more its complexity. Due to the uncertainty in the process of assessment, one of the key problems is the representation of assessment results. Though there exists many methods that can deal with uncertain information, however, they have more or less deficiencies. In this paper, a new representation of uncertain information, called D numbers, is presented. It extends the Dempster-Shafer theory. By using D numbers, a new method is developed for the bridge condition assessment. Compared to these existing methods, the proposed method is simpler and more effective. An illustrative case is given to show the effectiveness of the new method. PMID:24696639

The importance of α-CT and Salt bridges in the Formation of Insulin and its Receptor Complex by Computational Simulation.

PubMed

Dehghan-Shasaltaneh, Marzieh; Lanjanian, Hossein; Riazi, Gholam Hossein; Masoudi-Nejad, Ali

2018-01-01

Insulin hormone is an important part of the endocrine system. It contains two polypeptide chains and plays a pivotal role in regulating carbohydrate metabolism. Insulin receptors (IR) located on cell surface interacts with insulin to control the intake of glucose. Although several studies have tried to clarify the interaction between insulin and its receptor, the mechanism of this interaction remains elusive because of the receptor's structural complexity and structural changes during the interaction. In this work, we tried to fractionate the interactions. Therefore, sequential docking method utilization of HADDOCK was used to achieve the mentioned goal, so the following processes were done: the first, two pdb files of IR i.e., 3LOH and 3W11 were concatenated using modeller. The second, flexible regions of IR were predicted by HingeProt. Output files resulting from HingeProt were uploaded into HADDOCK. Our results predict new salt bridges in the complex and emphasize on the role of salt bridges to maintain an inverted V structure of IR. Having an inverted V structure leads to activate intracellular signaling pathway. In addition to presence salt bridges to form a convenient structure of IR, the importance of α-chain of carboxyl terminal (α-CT) to interact with insulin was surveyed and also foretokened new insulin/IR contacts, particularly at site 2 (rigid parts 2 and 3). Finally, several conformational changes in residues Asn711-Val715 of α-CT were occurred, we suggest that α-CT is a suitable situation relative to insulin due to these conformational alterations.

3. ENVIRONMENT, FROM WEST, SHOWING BOSTON STREET BRIDGE CARRYING BOSTON ...

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

3. ENVIRONMENT, FROM WEST, SHOWING BOSTON STREET BRIDGE CARRYING BOSTON STREET OVER HARRIS CREEK SEWER, WITH PORTION OF AMERICAN CAN COMPANY COMPLEX - Boston Street Bridge, Spanning Harris Creek Sewer at Boston Street, Baltimore, Independent City, MD

Unusual bridging of three nitrates with two bridgehead protons in an octaprotonated azacryptand

PubMed Central

Saeed, Musabbir A.; Fronczek, Frank R.; Huang, Ming-Ju; Hossain, Md. Alamgir

2010-01-01

Structural analysis of the nitrate complex of a thiophene-based azacryptand suggests that three nitrates are bridged with two bridgehead protons which play the topological role of two transition metal ions in a classical Werner type coordination complex bridging three anions. PMID:20066306

Roy D. Bridges Bridge

NASA Image and Video Library

2003-08-06

From left, incoming KSC Director James W. Kennedy looks on as departing KSC Director Roy D. Bridges Jr. shakes hands with the 45th Space Wing Commander Brig. Gen. J. Gregory Pavlovich. The occasion is the unveiling of the new sign on the NASA Causeway naming the bridge for Bridges who is leaving KSC to become the director of NASA's Langley Research Center, Hampton, Va. The bridge spans the Banana River on the NASA Causeway and connects Kennedy Space Center and Cape Canaveral Air Force Station.

Utility of 3D printed temporal bones in pre-surgical planning for complex BoneBridge cases.

PubMed

Mukherjee, Payal; Cheng, Kai; Flanagan, Sean; Greenberg, Simon

2017-08-01

With the advent of single-sided hearing loss increasingly being treated with cochlear implantation, bone conduction implants are reserved for cases of conductive and mixed hearing loss with greater complexity. The BoneBridge (BB, MED-EL, Innsbruck, Austria) is an active fully implantable device with no attenuation of sound energy through soft tissue. However, the floating mass transducer (FMT) part of the device is very bulky, which limits insertion in complicated ears. In this study, 3D printed temporal bones of patients were used to study its utility in preoperative planning on complicated cases. Computed tomography (CT) scans of 16 ears were used to 3D print their temporal bones. Three otologists graded the use of routine preoperative planning provided by MED-EL and that of operating on the 3D printed bone of the patient. Data were collated to assess the advantage and disadvantage of the technology. There was a statistically significant benefit in using 3D printed temporal bones to plan surgery for difficult cases of BoneBridge surgery compared to the current standard. Surgeons preferred to have the printed bones in theatre to plan their drill sites and make the transition of the planning to the patient's operation more precise. 3D printing is an innovative use of technology in the use of preoperative planning for complex ear surgery. Surgical planning can be done on the patient's own anatomy which may help to decrease operating time, reduce cost, increase surgical precision and thus reduce complications.

Tetranuclear copper(II) complexes bridged by alpha-D-glucose-1-phosphate and incorporation of sugar acids through the Cu4 core structural changes.

PubMed

Kato, Merii; Sah, Ajay Kumar; Tanase, Tomoaki; Mikuriya, Masahiro

2006-08-21

Tetranuclear copper(II) complexes containing alpha-D-glucose-1-phosphate (alpha-D-Glc-1P), [Cu4(mu-OH){mu-(alpha-D-Glc-1P)}2(bpy)4(H2O)2]X3 [X = NO3 (1a), Cl (1b), Br (1c)], and [Cu4(mu-OH){mu-(alpha-D-Glc-1P)}2(phen)4(H2O)2](NO3)3 (2) were prepared by reacting the copper(II) salt with Na2[alpha-D-Glc-1P] in the presence of diimine ancillary ligands, and the structure of 2 was characterized by X-ray crystallography to comprise four {Cu(phen)}2+ fragments connected by the two sugar phosphate dianions in 1,3-O,O' and 1,1-O mu4-bridging fashion as well as a mu-hydroxo anion. The crystal structure of 2 involves two chemically independent complex cations in which the C2 enantiomeric structure for the trapezoidal tetracopper(II) framework is switched according to the orientation of the alpha-D-glucopyranosyl moieties. Temperature-dependent magnetic susceptibility data of 1a indicated that antiferromagnetic spin coupling is operative between the two metal ions joined by the hydroxo bridge (J = -52 cm(-1)) while antiferromagnetic interaction through the Cu-O-Cu sugar phosphate bridges is weak (J = -13 cm(-1)). Complex 1a readily reacted with carboxylic acids to afford the tetranuclear copper(II) complexes, [Cu4{mu-(alpha-D-Glc-1P)}2(mu-CA)2(bpy)4](NO3)2 [CA = CH3COO (3), o-C6H4(COO)(COOH) (4)]. Reactions with m-phenylenediacetic acid [m-C6H4(CH2COOH)2] also gave the discrete tetracopper(II) cationic complex [Cu4{mu-(alpha-D-Glc-1P)}2(mu-m-C6H4(CH2COO)(CH2COOH))2(bpy)4](NO3)2 (5a) as well as the cluster polymer formulated as {[Cu4{mu-(alpha-D-Glc-1P)}2(mu-m-C6H4(CH2COO)2)(bpy)4](NO3)2}n (5b). The tetracopper structure of 1a is converted into a symmetrical rectangular core in complexes 3, 4, and 5b, where the hydroxo bridge is dissociated and, instead, two carboxylate anions bridge another pair of Cu(II) ions in a 1,1-O monodentate fashion. The similar reactions were applied to incorporate sugar acids onto the tetranuclear copper(II) centers. Reactions of 1a with delta

Geometries and properties of bimetallic phosphido-bridged complex Cp(CO) 2W(μ-PPh 2)W(CO) 5 and Cp(CO) 3W(μ-PPh 2)W(CO) 5

NASA Astrophysics Data System (ADS)

Wang, Fang; Yang, Hongmei; Yang, Zuoyin; Zhang, Jingchang; Cao, Weiliang

2007-01-01

Complete geometry optimizations were carried out by HF and DFT methods to study the molecular structure of binuclear transition-metal compounds (Cp(CO) 3W(μ-PPh 2)W(CO) 5) (I) and (Cp(CO) 2W(μ-PPh 2)W(CO) 5) (II). A comparison of the experimental data and calculated structural parameters demonstrates that the most accurate geometry parameters are predicted by the MPW1PW91/LANL2DZ among the three DFT methods. Topological properties of molecular charge distributions were analyzed with the theory of atoms in molecules. (3, -1) critical points, namely bond critical point, were found between the two tungsten atoms, and between W1 and C10 in complex II, which confirms the existence of the metal-metal bond and a semi-bridging CO between the two tungsten atoms. The result provided a theoretical guidance of detailed study on the binuclear phosphido-bridged complex containing transition metal-metal bond, which could be useful in the further study of the heterobimetallic phosphido-bridged complexes.

Electronic communication in phosphine substituted bridged dirhenium complexes - clarifying ambiguities raised by the redox non-innocence of the C4H2- and C4-bridges.

PubMed

Li, Yan; Blacque, Olivier; Fox, Thomas; Luber, Sandra; Polit, Walther; Winter, Rainer F; Venkatesan, Koushik; Berke, Heinz

2016-04-07

The mononuclear rhenium carbyne complex trans-[Re(C[triple bond, length as m-dash]CSiMe3)([triple bond, length as m-dash]C-Me)(PMe3)4][PF6] (2) was prepared in 90% yield by heating a mixture of the dinitrogen complex trans-[ReCl(N2)(PMe3)4] (1), TlPF6, and an excess of HC[triple bond, length as m-dash]CSiMe3. 2 could be deprotonated with KOtBu to the vinylidene complex trans-[Re(C[triple bond, length as m-dash]CSiMe3)([double bond, length as m-dash]C[double bond, length as m-dash]CH2)(PMe3)4] (3) in 98% yield. Oxidation of 3 with 1.2 equiv. of [Cp2Fe][PF6] at -78 °C gave the Cβ-C'β coupled dinuclear rhenium biscarbyne complex trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-CH2-CH2-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 (5) in 92% yield. Deprotonation of 5 with an excess of KOtBu in THF produced the diamagnetic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[double bond, length as m-dash]C[double bond, length as m-dash]CH-CH[double bond, length as m-dash]C[double bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)] complex (E-6(S)) in 87% yield with an E-butadienediylidene bridge. Density functional theory (DFT) calculations of E-6(S) confirmed its singlet ground state. The Z-form of 6 (Z-6(S)) could not be observed, which is in accord with its DFT calculated 17.8 kJ mol(-1) higher energy. Oxidation of E-6 with 2 equiv. of [Cp2Fe][PF6] resulted in the stable diamagnetic dicationic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-CH[double bond, length as m-dash]CH-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 complex (E-6[PF6]2) with an ethylenylidene dicarbyne structure of the bridge. The paramagnetic mixed-valence (MV) complex E-6[PF6] was obtained by comproportionation of E-6(S) and E-6[PF6]2 or by oxidation of E-6(S) with 1 equiv. of [Cp2Fe][PF6]. The

Doubly end-on azido bridged mixed-valence cobalt trinuclear complex: Spectral study, VTM, inhibitory effect and antimycobacterial activity on human carcinoma and tuberculosis cells

NASA Astrophysics Data System (ADS)

Datta, Amitabha; Das, Kuheli; Sen, Chandana; Karan, Nirmal Kumar; Huang, Jui-Hsien; Lin, Chia-Her; Garribba, Eugenio; Sinha, Chittaranjan; Askun, Tulin; Celikboyun, Pinar; Mane, Sandeep B.

2015-09-01

Doubly end-on azido-bridged mixed-valence trinuclear cobalt complex, [Co3(L)2(N3)6(CH3OH)2] (1) is afforded by employing a potential monoanionic tetradentate-N2O2 Schiff base precursor (2-[{[2-(dimethylamino)ethyl]imino}methyl]-6-methoxyphenol; HL). Single crystal X-ray structure reveals that in 1, the adjacent CoII and CoIII ions are linked by double end-on azido bridges and thus the full molecule is generated by the site symmetry of a crystallographic twofold rotation axis. Complex 1 is subjected on different spectral analysis such as IR, UV-vis, emission and EPR spectroscopy. On variable temperature magnetic study, we observe that during cooling, the χMT values decrease smoothly until 15 K and then reaches to the value 1.56 cm3 K mol-1 at 2 K. Complex 1 inhibits the cell growth on human lung carcinoma (A549 cells), human colorectal (COLO 205 and HT-29 cells), and human heptacellular (PLC5 cells) carcinoma cells. Complex 1 exhibits anti-mycobacterial activity and considerable efficacy on Mycobacterium tuberculosis H37Rv ATCC 27294 and H37Ra ATCC 25177 strains.

Structural characterization of a bridged 99Tc-Sn-dimethylglyoxime complex: implications for the chemistry of 99mTc-radiopharmaceuticals prepared by the Sn (II) reduction of pertechnetate.

PubMed Central

Deutsch, E; Elder, R C; Lange, B A; Vaal, M J; Lay, D G

1976-01-01

Reduction of pertechnetate by tin(II) in the presence of dimethylglyoxime is shown, by single crystal x-ray analysis, to yield a technetium-tin-dimethylglyoxime complex in which tin and technetium are intimately connected by a triple bridging arrangement. One bridge consists of a single oxygen atom and it is hypothesized that this bridge arises from the inner sphere reduction of technetium by tin(II), the electrons being transferred through a technetium "yl" oxygen which eventually becomes the bridging atom. Two additional bridges arise from two dimethylglyoxime ligands that function as bidentate nitrogen donors towards Tc and monodentate oxygen donors towards Sn. The tin atom can thus be viewed as providing a three-pronged "cap" on one end of the Tc-dimethylglyoxime complex. The additional coordination sites around Tc are occupied by the two nitrogens of a third dimethylglyoxime ligand, making the Tc seven-coordinate. The additional coordination sites around Sn are occupied by three chloride anions, giving the Sn a fac octahedral coordination environment. From indirect evidence the oxidation states of tin and technetium are tentatively assigned to be IV and V, respectively. Since most 99mTc-radiopharmaceuticals are synthesized by the tin(II) reduction of pertechnetate, it is likely that the Sn-O-Tc linkage described in this work is an important feature of the chemistry of these species. This linkage also provides a ready rationale for the close association of tin and technetium observed in many 99mTc-radiopharmaceuticals. PMID:1069984

X-ray crystal structure and theoretical study of a new dinuclear Cu(II) complex with two different geometry centers bridged with an oxo group

NASA Astrophysics Data System (ADS)

Golbedaghi, Reza; Azimi, Saeid; Molaei, Atefeh; Hatami, Masoud; Notash, Behrouz

2017-10-01

A new Schiff base ligand HL, 1,3-bis(2-((Z)-(2-aminoethylimino)methyl)phenoxy)ethylene di amine, has been synthesized from the reaction of a new aldehyde and ethylenediamine. After preparation the Schiff base, a new dinuclear Cu(II) complex with two different geometry for each metal ion was synthesized. Single crystal X-ray structure analysis of the complex Cu(II) showed that the complex is binuclear and all nitrogen and oxygen atoms of ligand (N4O3) are coordinated to two Cu(II) center ions. The crystal structure studying shows, a perchlorate ion has been coordinated to the two Cu(II) metal centers as bridged and another perchlorate coordinated to the one of Cu(II) ion as terminal. However, two interesting structures square pyramidal and distorted octahedral Cu(II) ions are bridged asymmetrically by a perchlorate ion and oxygen of hydroxyl group of Schiff base ligand. In addition, we had a theoretical study to have a comparison of experimental and theoretical results we determined the HOMO and LUMO orbitals.

Earthquake fragility assessment of curved and skewed bridges in Mountain West region : research brief.

DOT National Transportation Integrated Search

2016-09-01

the ISSUE : the RESEARCH : Earthquake Fragility : Assessment of Curved : and Skewed Bridges in : Mountain West Region : Reinforced concrete bridges with both skew and curvature are common in areas with complex terrains. : These bridges are irregular ...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

Exceptionally high lactide polymerization activity of zirconium complexes with bridged diketiminate ligands.

PubMed

El-Zoghbi, Ibrahim; Whitehorne, Todd J J; Schaper, Frank

2013-07-07

A cyclohexanediyl-bridged, bis(N-xylyl) diketiminate ligand, (±)-C6H10(nacnac(Xyl)H)2, LH2 (Xyl = 2,6-dimethylphenyl), was obtained from the reaction of [(2,6-dimethylphenyl)amino]-pent-3-en-2-one first with Meerwein's salt, then with (±)-cyclohexanediamine. The reaction of the ligand with Zr(NMe2)4 yielded LZr(NMe2)2. Protonation of the remaining diamide ligands with EtOH or [H2NMe2]Cl yielded LZr(OEt)2 and LZrCl2, respectively. The latter complex was also obtained by the reaction of LH2 first with nBuLi and then with ZrCl4(THF)2. The dichloride complex yielded LZr(OEt)2 and LZrMe2 upon reaction with NaOEt or MeLi/AlMe3, respectively. X-ray diffraction studies showed a trans-configuration of the ancillary ligands in LZrCl2 and LZrMe2, and a cis-configuration in LZr(NMe2)2 and LZr(OEt)2. LZr(OEt)2 was tested as a catalyst for the polymerization of rac-lactide. Kinetic investigations yielded a rate law first order in catalyst and monomer and a rate constant k = 14(1) L mol(-1) s(-1), the latter being orders of magnitude higher than typical activities for group 4 complexes in lactide polymerization. Analyses of the obtained polymer revealed an atactic polymer and broad polymer molecular weight distributions with sizeable fractions of cyclic oligomers. The influence of contaminants on the polymerization activity was examined: while lactic acid deactivates the catalyst, addition of up to 1 equiv. of water or para-toluenesulfonic acid revitalized catalysts not showing maximum activity.

Crystal structure of a mixed-ligand dinuclear Ba-Zn complex with 2-meth-oxy-ethanol having tri-phenyl-acetate and chloride bridges.

PubMed

Utko, Józef; Sobocińska, Maria; Dobrzyńska, Danuta; Lis, Tadeusz

2015-07-01

The dinuclear barium-zinc complex, μ-chlorido-1:2κ(2) Cl:Cl-chlorido-2κCl-bis-(2-meth-oxy-ethanol-1κO)bis-(2-meth-oxy-ethanol-1κ(2) O,O')bis-(μ-tri-phenyl-acetato-1:2κ(2) O:O')bariumzinc, [BaZn(C20H15O2)2Cl2(C3H8O2)4], has been synthesized by the reaction of barium tri-phenyl-acetate, anhydrous zinc chloride and 2-meth-oxy-ethanol in the presence of toluene. The barium and zinc metal cations in the dinuclear complex are linked via one chloride anion and carboxyl-ate O atoms of the tri-phenyl-acetate ligands, giving a Ba⋯Zn separation of 3.9335 (11) Å. The irregular nine-coordinate BaO8Cl coordination centres comprise eight O-atom donors, six of them from 2-meth-oxy-ethanol ligands (four from two bidentate O,O'-chelate inter-actions and two from monodentate inter-actions), two from bridging tri-phenyl-acetate ligands and one from a bridging Cl donor. The distorted tetra-hedral coordination sphere of zinc comprises two O-atom donors from the tri-phenyl-acetate ligands and two Cl donors (one bridging and one terminal). In the crystal, O-H⋯Cl, O-H⋯O and C-H⋯Cl inter-molecular inter-actions form a layered structure, lying parallel to (001).

Syntheses, structures, and properties of imidazolate-bridged Cu(II)-Cu(II) and Cu(II)-Zn(II) dinuclear complexes of a single macrocyclic ligand with two hydroxyethyl pendants.

PubMed

Li, Dongfeng; Li, Shuan; Yang, Dexi; Yu, Jiuhong; Huang, Jin; Li, Yizhi; Tang, Wenxia

2003-09-22

The imidazolate-bridged homodinuclear Cu(II)-Cu(II) complex, [(CuimCu)L]ClO(4).0.5H(2)O (1), and heterodinuclear Cu(II)-Zn(II) complex, [(CuimZnL(-)(2H))(CuimZnL(-)(H))](ClO(4))(3) (2), of a single macrocyclic ligand with two hydroxyethyl pendants, L (L = 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22,2,2,2(11,14)]triaconta-1,11,13,24,27,29-hexaene), have been synthesized as possible models for copper-zinc superoxide dismutase (Cu(2),Zn(2)-SOD). Their crystal structures analyzed by X-ray diffraction methods have shown that the structures of the two complexes are markedly different. Complex 1 crystallizes in the orthorhombic system, containing an imidazolate-bridged dicopper(II) [Cu-im-Cu](3+) core, in which the two copper(II) ions are pentacoordinated by virtue of an N4O environment with a Cu.Cu distance of 5.999(2) A, adopting the geometry of distorted trigonal bipyramid and tetragonal pyramid, respectively. Complex 2 crystallizes in the triclinic system, containing two similar Cu-im-Zn cores in the asymmetric unit, in which both the Cu(II) and Zn(II) ions are pentacoordinated in a distorted trigonal bipyramid geometry, with the Cu.Zn distance of 5.950(1)/5.939(1) A, respectively. Interestingly, the macrocyclic ligand with two arms possesses a chairlike (anti) conformation in complex 1, but a boatlike (syn) conformation in complex 2. Magnetic measurements and ESR spectroscopy of complex 1 have revealed the presence of an antiferromagnetic exchange interaction between the two Cu(II) ions. The ESR spectrum of the Cu(II)-Zn(II) heterodinuclear complex 2 displayed a typical signal for mononuclear trigonal bipyramidal Cu(II) complexes. From pH-dependent ESR and electronic spectroscopic studies, the imidazolate bridges in the two complexes have been found to be stable over broad pH ranges. The cyclic voltammograms of the two complexes have been investigated. Both of the two complexes can catalyze the dismutation of superoxide and show rather high activity.

Steel bridge retrofit evaluation

NASA Astrophysics Data System (ADS)

Prine, David W.

1998-03-01

The development of a retrofit design aimed at retarding or eliminating fatigue crack growth in a large bridge can be a very difficult and expensive procedure. Analytical techniques frequently do not provide sufficient accuracy when applied to complex structural details. The Infrastructure Technology Institute (ITI) of Northwestern University, under contract to the California Department of Transportation (Caltrans), recently applied experimental state-of-the-art NDE technology to the Interstate 80 bridge over the Sacramento River near Sacramento, California (Bryte Bend). Acoustic emission monitoring was applied in conjunction with strain gage monitoring to aid in characterizing the retrofits' effect on existing active fatigue cracks. The combined test results clearly showed that one retrofit design was superior to the other.

Rational design of azide-bridged bimetallic complexes. Crystal structure and magnetic properties of Fe(III)MFe(III) (M = Ni(II) and Cu(II)) trinuclear species.

PubMed

Colacio, Enrique; Costes, Jean-Pierre; Domínguez-Vera, José M; Maimoun, Ikram Ben; Suárez-Varela, José

2005-01-28

The first examples of azide-bridged bimetallic trinuclear complexes ([M(cyclam)][FeL(N3)(mu1,5-N3)]2) (H2L = 4,5-dichloro-1,2-bis(pyridine-2-carboxamido) benzene) have been structurally and magnetically characterized.

Optimizing the Electronic Properties of Photoactive Anticancer Oxypyridine-Bridged Dirhodium(II,II) Complexes

DOE PAGES

Li, Zhanyong; David, Amanda; Albani, Bryan A.; ...

2014-12-01

A series of partial paddlewheel dirhodium compounds of general formula cis-[Rh 2(xhp) 2(CH 3CN) n][BF 4] 2 (n = 5 or 6) were synthesized {xhp = 6-R-2-oxypyridine ligands, R = -CH 3 (mhp), -F (fhp), -Cl (chp)}. X-ray crystallographic studies indicate the aforementioned compounds contain two cis-oriented bridging xhp ligands, with the remaining sites being coordinated by CH 3CN ligands. The lability of the equatorial (eq) CH 3CN groups in these complexes in solution is in the order -CH 3 > -Cl > -F, in accord with the more electron rich bridging ligands exerting a stronger trans effect. In themore » case of cis-[Rh 2(chp) 2(CH 3CN) 6][BF 4] 2 (5), light irradiation enhances the production of the aqua adducts in which eq CH 3CN is replaced by H 2O molecules, whereas the formation of the aqua species for cis-[Rh 2(fhp) 2(CH 3CN) 6][BF 4] 2 (7) is only slightly increased by irradiation. The potential of both compounds to act as photochemotherapy agents was evaluated. A 16.4-fold increase in cytotoxicity against the HeLa cell line was observed for 5 upon 30 min irradiation (λ > 400 nm), in contrast to the nontoxic compound 7, which is in accord with the results from the photochemistry. Furthermore, the cell death mechanism induced by 5 was determined to be apoptosis. In conclusion, these results clearly demonstrate the importance of tuning the ligand field around the dimetal center to maximize the photoreactivity and achieve the best photodynamic action.« less

Low cost structural health monitoring of bridges using wireless SenSpot sensors.

DOT National Transportation Integrated Search

2012-05-01

Deterioration of highway bridges is a common, yet complex problem. To protect highway bridges, this : project combines a number of recent and emerging technologies microstructured sensing, ultra-lowpower : wireless communication, and advanced mic...

Monochloro non-bridged half-metallocene-type zirconium complexes containing phosphine oxide-(thio)phenolate chelating ligands as efficient ethylene polymerization catalysts.

PubMed

Tang, Xiao-Yan; Wang, Yong-Xia; Liu, San-Rong; Liu, Jing-Yu; Li, Yue-Sheng

2013-01-14

A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.

Investigating vibrational anharmonic couplings in cyanide-bridged transition metal mixed valence complexes using two-dimensional infrared spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slenkamp, Karla M.; Lynch, Michael S.; Van Kuiken, Benjamin E.

2014-02-28

Using polarization-selective two-dimensional infrared (2D IR) spectroscopy, we measure anharmonic couplings and angles between the transition dipole moments of the four cyanide stretching (ν{sub CN}) vibrations found in [(NH{sub 3}){sub 5}Ru{sup III}NCFe{sup II}(CN){sub 5}]{sup −} (FeRu) dissolved in D{sub 2}O and formamide and [(NC){sub 5}Fe{sup II}CNPt{sup IV}(NH{sub 3}){sub 4}NCFe{sup II}(CN){sub 5}]{sup 4−} (FePtFe) dissolved in D{sub 2}O. These cyanide-bridged transition metal complexes serve as model systems for studying the role of high frequency vibrational modes in ultrafast photoinduced charge transfer reactions. Here, we focus on the spectroscopy of the ν{sub CN} modes in the electronic ground state. The FTIR spectramore » of the ν{sub CN} modes of the bimetallic and trimetallic systems are strikingly different in terms of frequencies, amplitudes, and lineshapes. The experimental 2D IR spectra of FeRu and FePtFe and their fits reveal a set of weakly coupled anharmonic ν{sub CN} modes. The vibrational mode anharmonicities of the individual ν{sub CN} modes range from 14 to 28 cm{sup −1}. The mixed-mode anharmonicities range from 2 to 14 cm{sup −1}. In general, the bridging ν{sub CN} mode is most weakly coupled to the radial ν{sub CN} mode, which involves the terminal CN ligands. Measurement of the relative transition dipole moments of the four ν{sub CN} modes reveal that the FeRu molecule is almost linear in solution when dissolved in formamide, but it assumes a bent geometry when dissolved in D{sub 2}O. The ν{sub CN} modes are modelled as bilinearly coupled anharmonic oscillators with an average coupling constant of 6 cm{sup −1}. This study elucidates the role of the solvent in modulating the molecular geometry and the anharmonic vibrational couplings between the ν{sub CN} modes in cyanide-bridged transition metal mixed valence complexes.« less

A comparative study of magnetization dynamics in dinuclear dysprosium complexes featuring bridging chloride or trifluoromethanesulfonate ligands.

PubMed

Burns, Corey P; Wilkins, Branford O; Dickie, Courtney M; Latendresse, Trevor P; Vernier, Larry; Vignesh, Kuduva R; Bhuvanesh, Nattamai S; Nippe, Michael

2017-07-25

We utilized a rigid ligand platform PyCp 2 2- (PyCp 2 2- = [2,6-(CH 2 C 5 H 3 ) 2 C 5 H 3 N] 2- ) to isolate dinuclear Dy 3+ complexes [(PyCp 2 )Dy-(μ-O 2 SOCF 3 )] 2 (1) and [(PyCp 2 )Dy-(μ-Cl)] 2 (3) as well as the mononuclear complex (PyCp 2 )Dy(OSO 2 CF 3 )(thf) (2). Compounds 1 and 2 are the first examples of organometallic Dy 3+ complexes featuring triflate binding. The isolation of compounds 1 and 3 allows us to comparatively evaluate the effects of the bridging anions on the magnetization dynamics of the dinuclear systems. Our investigations show that although the exchange coupling interactions differ for 1 and 3, the dynamic magnetic properties are dominated by relaxation via the first excited state Kramers doublet of the individual Dy sites. Compounds 1 and 3 exhibit barriers to magnetization reversal (U eff = 49 cm -1 ) that can be favorably compared to those of the previously reported examples of [Cp 2 Dy(μ-Cl)] 2 (U eff = 26 cm -1 ) and [Cp 2 Dy(thf)(μ-Cl)] 2 (U eff = 34 cm -1 ).

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

Synthesis of Unsupported d(1)-d(x) Oxido-Bridged Heterobimetallic Complexes Containing V(IV): A New Direction for Metal-to-Metal Charge Transfer.

PubMed

Wu, Xinyuan; Huang, Tao; Lekich, Travis T; Sommer, Roger D; Weare, Walter W

2015-06-01

Heterobimetallic complexes composed only of first-row transition metals [(TMTAA)V(IV)═O→M(II)Py5Me2](OTf)2 (TMTAA = 7,16-dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine; Py5Me2 = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine; M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II); OTf = trifluoromethanesulfonate) have been synthesized through a dative interaction between a terminal oxido and M(II) metal centers. This is the first series of V(IV)═O→M(II) heterobimetallic complexes containing an unsupported oxido bridge. Among these five complexes, only V(IV)═O→Fe(II) (3b) has a clear new absorption band upon formation of the dinuclear species (502 nm, ε = 1700 M(-1) cm(-1)). This feature is assigned to a metal-to-metal charge transfer (MMCT) transition from V(IV) to Fe(II), which forms a V(V)-O-Fe(I) excited state. This assignment is supported by electrochemical data, electronic absorption profiles, and resonance Raman spectroscopy and represents the first report of visible-light induced MMCT in a heterobimetallic oxido-bridged molecule where the electron originates on a d(1) metal center.

Instability of the capillary bridge

NASA Astrophysics Data System (ADS)

Pare, Gounseti; Hoepffner, Jerome

2014-11-01

Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

Research of diagnosis sensors fault based on correlation analysis of the bridge structural health monitoring system

NASA Astrophysics Data System (ADS)

Hu, Shunren; Chen, Weimin; Liu, Lin; Gao, Xiaoxia

2010-03-01

Bridge structural health monitoring system is a typical multi-sensor measurement system due to the multi-parameters of bridge structure collected from the monitoring sites on the river-spanning bridges. Bridge structure monitored by multi-sensors is an entity, when subjected to external action; there will be different performances to different bridge structure parameters. Therefore, the data acquired by each sensor should exist countless correlation relation. However, complexity of the correlation relation is decided by complexity of bridge structure. Traditionally correlation analysis among monitoring sites is mainly considered from physical locations. unfortunately, this method is so simple that it cannot describe the correlation in detail. The paper analyzes the correlation among the bridge monitoring sites according to the bridge structural data, defines the correlation of bridge monitoring sites and describes its several forms, then integrating the correlative theory of data mining and signal system to establish the correlation model to describe the correlation among the bridge monitoring sites quantificationally. Finally, The Chongqing Mashangxi Yangtze river bridge health measurement system is regards as research object to diagnosis sensors fault, and simulation results verify the effectiveness of the designed method and theoretical discussions.

Vibration characteristics and damage detection in a suspension bridge

NASA Astrophysics Data System (ADS)

Wickramasinghe, Wasanthi R.; Thambiratnam, David P.; Chan, Tommy H. T.; Nguyen, Theanh

2016-08-01

Suspension bridges are flexible and vibration sensitive structures that exhibit complex and multi-modal vibration. Due to this, the usual vibration based methods could face a challenge when used for damage detection in these structures. This paper develops and applies a mode shape component specific damage index (DI) to detect and locate damage in a suspension bridge with pre-tensioned cables. This is important as suspension bridges are large structures and damage in them during their long service lives could easily go un-noticed. The capability of the proposed vibration based DI is demonstrated through its application to detect and locate single and multiple damages with varied locations and severity in the cables of the suspension bridge. The outcome of this research will enhance the safety and performance of these bridges which play an important role in the transport network.

82. DETAIL OF THE MUZZLE END OF THE LAUNCHER BRIDGE ...

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

82. DETAIL OF THE MUZZLE END OF THE LAUNCHER BRIDGE LOOKING NORTH SHOWING THE CONNECTING BRIDGE AND TWO LAUNCHING TUBES, Date unknown, circa 1952. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

BridgePBEE | BridgePBEE

Science.gov Websites

jacking Item 22: Bridge removal (column) Item 23: Bridge removal (portion) Item 24: Approach slab removal for: Search Menu Log in Register PEER Center - 325 Davis Hall, University of California, Berkeley, CA

Structure and magnetic properties of an unprecedented syn-anti μ-nitrito-1κO:2κO' bridged Mn(III)-salen complex and its isoelectronic and isostructural formate analogue.

PubMed

Kar, Paramita; Biswas, Rituparna; Drew, Michael G B; Ida, Yumi; Ishida, Takayuki; Ghosh, Ashutosh

2011-04-07

The preparation, crystal structures and magnetic properties of two new isoelectronic and isomorphous formate- and nitrite-bridged 1D chains of Mn(III)-salen complexes, [Mn(salen)(HCOO)](n) (1) and [Mn(salen)(NO(2))](n) (2), where salen is the dianion of N,N'-bis(salicylidene)-1,2-diaminoethane, are presented. The structures show that the salen ligand coordinates to the four equatorial sites of the metal ion and the formate or nitrite ions coordinate to the axial positions to bridge the Mn(III)-salen units through a syn-antiμ-1κO:2κO' coordination mode. Such a bridging mode is unprecedented in Mn(III) for formate and in any transition metal ion for nitrite. Variable-temperature magnetic susceptibility measurements of complexes 1 and 2 indicate the presence of ferromagnetic exchange interactions with J values of 0.0607 cm(-1) (for 1) and 0.0883 cm(-1) (for 2). The ac measurements indicate negligible frequency dependence for 1 whereas compound 2 exhibits a decrease of χ(ac)' and a concomitant increase of χ(ac)'' on elevating frequency around 2 K. This finding is an indication of slow magnetization reversal characteristic of single-chain magnets or spin-glasses. The μ-nitrito-1κO:2κO' bridge seems to be a potentially superior magnetic coupler to the formate bridge for the construction of single-molecule/-chain magnets as its coupling constant is greater and the χ(ac)' and χ(ac)'' show frequency dependence. © The Royal Society of Chemistry 2011

From bis(imidazole-2-thion-4-yl)phosphane to a flexible P-bridged bis(NHC) ligand and its silver complex.

PubMed

Majhi, Paresh Kumar; Schnakenburg, Gregor; Streubel, Rainer

2014-11-28

Synthesis of the first P(V)-bridged bis(NHC) ligand 7 was achieved via deprotonation of P(V)-functionalized bis(imidazolium) salt 6, which was obtained via oxidative desulfurization of bis(imidazole-2-thion-4-yl)phosphane 2. Bis(imidazolium) salt 6 was also employed to synthesize the corresponding silver complex 8. All new products were firmly established by spectroscopic and spectrometric methods as well as elemental analysis and, in addition, X-ray crystal structure analysis in the case of 3.

Myocardial Bridge

MedlinePlus

... 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 ...

ESBRI: a web server for evaluating salt bridges in proteins.

PubMed

Costantini, Susan; Colonna, Giovanni; Facchiano, Angelo M

2008-01-01

Salt bridges can play important roles in protein structure and function and have stabilizing and destabilizing effects in protein folding. ESBRI is a software available as web tool which analyses the salt bridges in a protein structure, starting from the atomic coordinates. In the case of protein complexes, the salt bridges between protein chains can be evaluated, as well as those among specific charged amino acids and the different protein subunits, in order to obtain useful information regard the protein-protein interaction. The service is available at the URL: http://bioinformatica.isa.cnr.it/ESBRI/

Mutation of the myosin converter domain alters cross-bridge elasticity

PubMed Central

Köhler, Jan; Winkler, Gerhard; Schulte, Imke; Scholz, Tim; McKenna, William; Brenner, Bernhard; Kraft, Theresia

2002-01-01

Elastic distortion of a structural element of the actomyosin complex is fundamental to the ability of myosin to generate motile forces. An elastic element allows strain to develop within the actomyosin complex (cross-bridge) before movement. Relief of this strain then drives filament sliding, or more generally, movement of a cargo. Even with the known crystal structure of the myosin head, however, the structural element of the actomyosin complex in which elastic distortion occurs remained unclear. To assign functional relevance to various structural elements of the myosin head, e.g., to identify the elastic element within the cross-bridge, we studied mechanical properties of muscle fibers from patients with familial hypertrophic cardiomyopathy with point mutations in the head domain of the β-myosin heavy chain. We found that the Arg-719 → Trp (Arg719Trp) mutation, which is located in the converter domain of the myosin head fragment, causes an increase in force generation and fiber stiffness under isometric conditions by 48–59%. Under rigor and relaxing conditions, fiber stiffness was 45–47% higher than in control fibers. Yet, kinetics of active cross-bridge cycling were unchanged. These findings, especially the increase in fiber stiffness under rigor conditions, indicate that cross-bridges with the Arg719Trp mutation are more resistant to elastic distortion. The data presented here strongly suggest that the converter domain that forms the junction between the catalytic and the light-chain-binding domain of the myosin head is not only essential for elastic distortion of the cross-bridge, but that the main elastic distortion may even occur within the converter domain itself. PMID:11904418

Distributed situation awareness in complex collaborative systems: A field study of bridge operations on platform supply vessels.

PubMed

Sandhåland, Hilde; Oltedal, Helle A; Hystad, Sigurd W; Eid, Jarle

2015-06-01

This study provides empirical data about shipboard practices in bridge operations on board a selection of platform supply vessels (PSVs). Using the theoretical concept of distributed situation awareness, the study examines how situation awareness (SA)-related information is distributed and coordinated at the bridge. This study thus favours a systems approach to studying SA, viewing it not as a phenomenon that solely happens in each individual's mind but rather as something that happens between individuals and the tools that they use in a collaborative system. Thus, this study adds to our understanding of SA as a distributed phenomenon. Data were collected in four field studies that lasted between 8 and 14 days on PSVs that operate on the Norwegian continental shelf and UK continental shelf. The study revealed pronounced variations in shipboard practices regarding how the bridge team attended to operational planning, communication procedures, and distracting/interrupting factors during operations. These findings shed new light on how SA might decrease in bridge teams during platform supply operations. The findings from this study emphasize the need to assess and establish shipboard practices that support the bridge teams' SA needs in day-to-day operations. Provides insights into how shipboard practices that are relevant to planning, communication and the occurrence of distracting/interrupting factors are realized in bridge operations.Notes possible areas for improvement to enhance distributed SA in bridge operations.

Thiolate-bridged dinuclear ruthenium and iron complexes as robust and efficient catalysts toward oxidation of molecular dihydrogen in protic solvents.

PubMed

Yuki, Masahiro; Sakata, Ken; Hirao, Yoshifumi; Nonoyama, Nobuaki; Nakajima, Kazunari; Nishibayashi, Yoshiaki

2015-04-01

Thiolate-bridged dinuclear ruthenium and iron complexes are found to work as efficient catalysts toward oxidation of molecular dihydrogen in protic solvents such as water and methanol under ambient reaction conditions. Heterolytic cleavage of the coordinated molecular dihydrogen at the dinuclear complexes and the sequential oxidation of the produced hydride complexes are involved as key steps to promote the present catalytic reaction. The catalytic activity of the dinuclear complexes toward the chemical oxidation of molecular dihydrogen achieves up to 10000 TON (turnover number), and electrooxidation of molecular dihydrogen proceeds quite rapidly. The result of the density functional theory (DFT) calculation on the reaction pathway indicates that a synergistic effect between the two ruthenium atoms plays an important role to realize the catalytic oxidation of molecular dihydrogen efficiently. The present dinuclear ruthenium complex is found to work as an efficient organometallic anode catalyst for the fuel cell. It is noteworthy that the present dinuclear complex worked not only as an effective catalyst toward chemical and electrochemical oxidation of molecular dihydrogen but also as a good anode catalyst for the fuel cell. We consider that the result described in this paper provides useful and valuable information to develop highly efficient and low-cost transition metal complexes as anode catalysts in the fuel cell.

Trinuclear ruthenium dioxolene complexes based on the bridging ligand hexahydroxytriphenylene: electrochemistry, spectroscopy, and near-infrared electrochromic behaviour associated with a reversible seven-membered redox chain.

PubMed

Grange, Christopher S; Meijer, Anthony J H M; Ward, Michael D

2010-01-07

The trinuclear complexes [{(R2bipy)2Ru}3(mu3-HHTP)](PF6)3 [1(PF6)3, R = H; 2(PF6)3, R = 4-tBu] contain three {Ru(R2bipy)2}2+ fragments connected to the triangular tris-chelating ligand hexahydroxytriphenylene (H6HHTP). This bridging ligand contains three dioxolene-type binding sites, each of which can reversibly convert between dianionic catecholate (cat), monoanionic semiquinone (sq) or neutral quinone (q) redox states. The bridging ligand as a whole can therefore exist in seven different redox states from fully reduced [cat,cat,cat]6- through to fully oxidised, neutral [q,q,q]. Cyclic voltammetry of 1(PF6)3 in MeCN reveals six redox processes of which the three at more positive potentials (the sq/q couples) are reversible but the three at more negative potentials (the sq/cat couples) are irreversible with distorted wave shapes due to the insolubility of the reduced forms of the complex. In contrast, the more soluble complex 2(PF6)3 displays six reversible one-electron redox processes making all components of a seven-membered redox chain accessible. UV/Vis/NIR spectro-electrochemical studies reveal rich spectroscopic behaviour, with--in particular--very intense transitions in the near-IR region in many of the oxidation states associated with Ru(II)-->(dioxolene) MLCT and bridging ligand centred pi-pi* transitions. TDDFT calculations were used to analyse the electronic spectra in all seven oxidation states; the calculated spectra generally show very good agreement with experiment, which has allowed a fairly complete assignment of the low-energy transitions. The strong electrochromism of the complexes in the near-IR region has formed the basis of an optical window in which a thin film of 1(PF6)3 or 2(PF6)3 on a conductive glass surface can be reversibly and rapidly switched between redox states that alternate between strongly absorbing or near-transparent at 1100 nm, with--for 2(PF6)3--the switching being stable and reversible in water over thousands of cycles.

Distributed situation awareness in complex collaborative systems: A field study of bridge operations on platform supply vessels

PubMed Central

Sandhåland, Hilde; Oltedal, Helle A; Hystad, Sigurd W; Eid, Jarle

2015-01-01

This study provides empirical data about shipboard practices in bridge operations on board a selection of platform supply vessels (PSVs). Using the theoretical concept of distributed situation awareness, the study examines how situation awareness (SA)-related information is distributed and coordinated at the bridge. This study thus favours a systems approach to studying SA, viewing it not as a phenomenon that solely happens in each individual's mind but rather as something that happens between individuals and the tools that they use in a collaborative system. Thus, this study adds to our understanding of SA as a distributed phenomenon. Data were collected in four field studies that lasted between 8 and 14 days on PSVs that operate on the Norwegian continental shelf and UK continental shelf. The study revealed pronounced variations in shipboard practices regarding how the bridge team attended to operational planning, communication procedures, and distracting/interrupting factors during operations. These findings shed new light on how SA might decrease in bridge teams during platform supply operations. The findings from this study emphasize the need to assess and establish shipboard practices that support the bridge teams' SA needs in day-to-day operations. Practitioner points Provides insights into how shipboard practices that are relevant to planning, communication and the occurrence of distracting/interrupting factors are realized in bridge operations. Notes possible areas for improvement to enhance distributed SA in bridge operations. PMID:26028823

Fixation of carbon dioxide by macrocyclic lanthanide(III) complexes under neutral conditions producing self-assembled trimeric carbonato-bridged compounds with μ3-η2:η2:η2 bonding.

PubMed

Bag, Pradip; Dutta, Supriya; Biswas, Papu; Maji, Swarup Kumar; Flörke, Ulrich; Nag, Kamalaksha

2012-03-28

A series of mononuclear lanthanide(III) complexes [Ln(LH(2))(H(2)O)(3)Cl](ClO(4))(2) (Ln = La, Nd, Sm, Eu, Gd, Tb, Lu) of the tetraiminodiphenolate macrocyclic ligand (LH(2)) in 95 : 5 (v/v) methanol-water solution fix atmospheric carbon dioxide to produce the carbonato-bridged trinuclear complexes [{Ln(LH(2))(H(2)O)Cl}(3)(μ(3)-CO(3))](ClO(4))(4)·nH(2)O. Under similar conditions, the mononuclear Y(III) complex forms the dimeric compound [{Y(LH(2))(H(2)O)Cl}(μ(2)-CO(3)){Y(LH(2))(H(2)O)(2)}](ClO(4))(3)·4H(2)O. These complexes have been characterized by their IR and NMR ((1)H, (13)C) spectra. The X-ray crystal structures have been determined for the trinuclear carbonato-bridged compounds of Nd(III), Gd(III) and Tb(III) and the dinuclear compound of Y(III). In all cases, each of the metal centers are 8-coordinate involving two imine nitrogens and two phenolate oxygens of the macrocyclic ligand (LH(2)) whose two other imines are protonated and intramolecularly hydrogen-bonded with the phenolate oxygens. The oxygen atoms of the carbonate anion in the trinuclear complexes are bonded to the metal ions in tris-bidentate μ(3)-η(2):η(2):η(2) fashion, while they are in bis-bidentate μ(2)-η(2):η(2) mode in the Y(III) complex. The magnetic properties of the Gd(III) complex have been studied over the temperature range 2 to 300 K and the magnetic susceptibility data indicate a very weak antiferromagnetic exchange interaction (J = -0.042 cm(-1)) between the Gd(III) centers (S = 7/2) in the metal triangle through the carbonate bridge. The luminescence spectral behaviors of the complexes of Sm(III), Eu(III), and Tb(III) have been studied. The ligand LH(2) acts as a sensitizer for the metal ions in an acetonitrile-toluene glassy matrix (at 77 K) and luminescence intensities of the complexes decrease in the order Eu(3+) > Sm(3+) > Tb(3+).

Synthesis and structural studies of two pyridine-armed reinforced cyclen chelators and their transition metal complexes.

PubMed

Wilson, Kevin R; Cannon-Smith, Desiray J; Burke, Benjamin P; Birdsong, Orry C; Archibald, Stephen J; Hubin, Timothy J

2016-08-16

Two novel pyridine pendant-armed macrocycles structurally reinforced by an ethyl bridge, either between adjacent nitrogens (for side-bridged) or non-adjacent nitrogens (for cross-bridged), have been synthesized and complexed with a range of transition metal ions (Co 2+ , Ni 2+ , Cu 2+ and Zn 2+ ). X-ray crystal structures of selected cross-bridged complexes were obtained which showed the characteristic cis-V configuration with potential labile cis binding sites. The complexes have been characterized by their electronic spectra and magnetic moments, which show the expected high spin divalent metal complex in most cases. Exceptions are the nickel side-bridged complex, which shows a mixture of high-spin and low spin, and the cobalt cross-bridged complex which has oxidized to cobalt(III). Cyclic voltammetry in acetonitrile was carried out to assess the potential future use of these complexes in oxidation catalysis. Selected complexes offer significant catalytic potential enhanced by the addition of the pyridyl arm to a reinforced cyclen backbone.

An improved bridge safety index for narrow bridges.

DOT National Transportation Integrated Search

1983-08-01

In this report, a new bridge safety index is developed based upon an extensive : statistical study of accident data on 78 bridges. A total of 655 accidents : were recorded at these bridges over the six-year period between 1974 and 1979. : Cluster ana...

Syntheses, crystal structures, magnetic properties, and EPR spectra of tetranuclear copper(II) complexes featuring pairs of "roof-shaped" Cu2X2 dimers with hydroxide, methoxide, and azide bridges.

PubMed

Graham, B; Hearn, M T; Junk, P C; Kepert, C M; Mabbs, F E; Moubaraki, B; Murray, K S; Spiccia, L

2001-03-26

Hydroxo- and methoxo-bridged tetranuclear copper(II) complexes of the tetramacrocyclic ligand 1,2,4,5-tetrakis(1,4,7-triazacyclonon-1-ylmethyl)benzene (Ldur), have been prepared from [Cu4Ldur(H2O)8](ClO4)8.9H2O (1). Addition of base to an aqueous solution of 1 gave [Cu4Ldur(mu2-OH)4](ClO4)4 (2). Diffusion of MeOH into a DMF solution of 2 produces [Cu4Ldur(mu2-OMe)4](ClO4)4.HClO4.2/3MeOH (3), a complex which hydrolyzes on exposure to moisture regenerating 2. The structurally related azido-bridged complex, [Cu4Ldur(mu2-N3)4](PF6)4.4H2O.6CH3CN (4), was produced by reaction of Ldur with 4 molar equiv of Cu(OAc)2.H2O and NaN3 in the presence of excess KPF6. Compounds 2-4 crystallize in the triclinic space group P1 (No. 2) with a = 10.248(1) A, b = 12.130(2) A, c = 14.353(2) A, alpha = 82.23(1) degrees, beta = 80.79(1) degrees, gamma = 65.71(1) degrees, and Z = 1 for 2, a = 10.2985(4) A, b = 12.1182(4) A, c = 13.9705(3) A, alpha = 89.978(2) degrees, beta = 82.038(2) degrees, gamma = 65.095(2) degrees, and Z = 1 for 3, and a = 12.059(2) A, b = 12.554(2) A, c = 14.051(2) A, alpha = 91.85(1) degrees, beta = 98.22(1) degrees, gamma = 105.62(1) degrees, and Z = 1 for 4. The complexes feature pairs of isolated dibridged copper(II) dimers with "roof-shaped" Cu2(mu2-X)2 cores (X = OH-, OMe-, N3-), as indicated by the dihedral angle between the two CuX2 planes (159 degrees for 2, 161 degrees for 3, and 153 degrees for 4). This leads to Cu.Cu distances of 2.940(4) A for 2, 2.962(1) A for 3, and 3.006(5) A for 4. Variable-temperature magnetic susceptibility measurements indicate weak antiferromagnetic coupling (J = -27 cm(-1)) for the hydroxo-bridged copper(II) centers in 2 and very strong antiferromagnetic coupling (J = -269 cm(-1)) for the methoxo-bridged copper(II) centers in 3. Pairs of copper(II) centers in 4 display the strongest ferromagnetic interaction (J = 94 cm(-1)) reported thus far for bis(mu2-1,1-azido)-bridged dicopper units. Spectral measurements on a neat powdered

Phosphonate Pendant Armed Propylene Cross-Bridged Cyclam: Synthesis and Evaluation as a Chelator for Cu-64

PubMed Central

2015-01-01

A propylene cross-bridged macrocyclic chelator with two phosphonate pendant arms (PCB-TE2P) was synthesized from cyclam. Various properties of the synthesized chelator, including Cu-complexation, Cu-complex stability, 64Cu-radiolabeling, and in vivo behavior, were studied and compared with those of a previously reported propylene cross-bridged chelator (PCB-TE2A). PMID:26617972

Bridging of double-stranded breaks by the nonhomologous end-joining ligation complex is modulated by DNA end chemistry.

PubMed

Reid, Dylan A; Conlin, Michael P; Yin, Yandong; Chang, Howard H; Watanabe, Go; Lieber, Michael R; Ramsden, Dale A; Rothenberg, Eli

2017-02-28

The nonhomologous end-joining (NHEJ) pathway is the primary repair pathway for DNA double strand breaks (DSBs) in humans. Repair is mediated by a core complex of NHEJ factors that includes a ligase (DNA Ligase IV; L4) that relies on juxtaposition of 3΄ hydroxyl and 5΄ phosphate termini of the strand breaks for catalysis. However, chromosome breaks arising from biological sources often have different end chemistries, and how these different end chemistries impact the way in which the core complex directs the necessary transitions from end pairing to ligation is not known. Here, using single-molecule FRET (smFRET), we show that prior to ligation, differences in end chemistry strongly modulate the bridging of broken ends by the NHEJ core complex. In particular, the 5΄ phosphate group is a recognition element for L4 and is critical for the ability of NHEJ factors to promote stable pairing of ends. Moreover, other chemical incompatibilities, including products of aborted ligation, are sufficient to disrupt end pairing. Based on these observations, we propose a mechanism for iterative repair of DSBs by NHEJ. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Extreme Changes in Stream Geomorphic Conditions induced by Fluvial Scour in Bridges

NASA Astrophysics Data System (ADS)

Özcan, O.; Ozcan, O.

2016-12-01

The numerous complexities associated with bridge scour have caused scour to be one of the most active topics of stream geomorphic research. The assessment of local scouring mechanism around bridge piers provides information for decision-making regarding the pile footing design, predicting the safety of bridges under critical scoured conditions, and as a result, may help prevent unnecessary loses. In the study, bridge design plans and HEC-RAS modeling were used for the assessment of changes in stream geomorphic conditions. The derived fluvial scour depths were compared with the field measurements and the empirical formula which is based on stream flow discharge rate, streambed condition and shape of river. Preliminary results revealed that bridge damage resulting from the flood event in 2003 induced substantial scour around bridge piles. Afterwards, significant stream bed change was observed under the influence of fluvial scour in another flood occurred in 2009. Consequently, geomorphic conditions of the stream bed should be considered in the structural design of the bridges.

28. BRIDGE NO. 9 APRON AND BRIDGE HINGE JOINT AND ...

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

28. BRIDGE NO. 9 APRON AND BRIDGE HINGE JOINT AND BRIDGE SUSPENSION SYSTEM SHOWING EYEBAR AND CABLE CONNECTIONS. LOOKING WEST. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

A novel bridge scour monitoring and prediction system

NASA Astrophysics Data System (ADS)

Valyrakis, Manousos; Michalis, Panagiotis; Zhang, Hanqing

2015-04-01

Earth's surface is continuously shaped due to the action of geophysical flows. Erosion due to the flow of water in river systems has been identified as a key problem in preserving ecological health but also a threat to our built environment and critical infrastructure, worldwide. As an example, it has been estimated that a major reason for bridge failure is due to scour. Even though the flow past bridge piers has been investigated both experimentally and numerically, and the mechanisms of scouring are relatively understood, there still lacks a tool that can offer fast and reliable predictions. Most of the existing formulas for prediction of bridge pier scour depth are empirical in nature, based on a limited range of data or for piers of specific shape. In this work, the use of a novel methodology is proposed for the prediction of bridge scour. Specifically, the use of an Adaptive Neuro-Fuzzy Inference System (ANFIS) is proposed to estimate the scour depth around bridge piers. In particular, various complexity architectures are sequentially built, in order to identify the optimal for scour depth predictions, using appropriate training and validation subsets obtained from the USGS database (and pre-processed to remove incomplete records). The model has five variables, namely the effective pier width (b), the approach velocity (v), the approach depth (y), the mean grain diameter (D50) and the skew to flow. Simulations are conducted with data groups (bed material type, pier type and shape) and different number of input variables, to produce reduced complexity and easily interpretable models. Analysis and comparison of the results indicate that the developed ANFIS model has high accuracy and outstanding generalization ability for prediction of scour parameters. The effective pier width (as opposed to skew to flow) is amongst the most relevant input parameters for the estimation. Training of the system to new bridge geometries and flow conditions can be achieved by

Bridge permeameter

DOEpatents

Graf, Darin C.; Warpinski, Norman R.

1996-01-01

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

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

PubMed

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.

29. BRIDGE NO. 13 APRON AND BRIDGE HINGE JOINT AND ...

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

29. BRIDGE NO. 13 APRON AND BRIDGE HINGE JOINT AND BRIDGE SUSPENSION SYSTEM (OLDER STYLE) SHOWING EYEBAR AND CABLE CONNECTIONS. LOOKING WEST. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

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

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

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

Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

NASA Astrophysics Data System (ADS)

Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

2015-03-01

Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

Bim from Laser SCANS… not Just for Buildings: Nurbs-Based Parametric Modeling of a Medieval Bridge

NASA Astrophysics Data System (ADS)

Barazzetti, L.; Banfi, F.; Brumana, R.; Previtali, M.; Roncoroni, F.

2016-06-01

Building Information Modelling is not limited to buildings. BIM technology includes civil infrastructures such as roads, dams, bridges, communications networks, water and wastewater networks and tunnels. This paper describes a novel methodology for the generation of a detailed BIM of a complex medieval bridge. The use of laser scans and images coupled with the development of algorithms able to handle irregular shapes allowed the creation of advanced parametric objects, which were assembled to obtain an accurate BIM. The lack of existing object libraries required the development of specific families for the different structural elements of the bridge. Finally, some applications aimed at assessing the stability and safety of the bridge are illustrated and discussed. The BIM of the bridge can incorporate this information towards a new "BIMonitoring" concept to preserve the geometric complexity provided by point clouds, obtaining a detailed BIM with object relationships and attributes.

Bridge permeameter

DOEpatents

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

1996-08-13

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

Bridge permeameter

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

Long-term bridge performance high priority bridge performance issues.

DOT National Transportation Integrated Search

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)...

Nondestructive evaluation of four sister bridges in Virginia using manual NDE technologies and robotic platform RABIT : final report.

DOT National Transportation Integrated Search

2015-07-01

Understanding the factors that influence the performance of a bridge is a very important topic and due to the : complexity of bridges, this is rather a hard task because there are multiple factors, which can influence the : performance of a bridge. T...

Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N⁴-methyl-3-thiosemicarbazone: crystal structure of a novel sulfur bridged copper(II) box-dimer.

PubMed

Jayakumar, K; Sithambaresan, M; Aiswarya, N; Kurup, M R Prathapachandra

2015-03-15

Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N(4)-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ=0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g||>g⊥>2.0023 and the g values in frozen DMF are consistent with the d(x2-y2) ground state. The thermal stabilities of some of the complexes were also determined. Copyright © 2014 Elsevier B.V. All rights reserved.

OVERVIEW OF BRIDGES WITH WAIKELE CANAL BRIDGE IN CENTER, OR&L ...

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

OVERVIEW OF BRIDGES WITH WAIKELE CANAL BRIDGE IN CENTER, OR&L BRIDGE IN BACKGROUND. SHOWING THE EARTHEN INCLINE THAT RAISES FARRINGTON HIGHWAY OVER THE FORMER OR&L TRACKS. NOTE THE 1963 WESTBOUND BRIDGE IN THE FOREGROUND. VIEW FACING EAST. - Waikele Canal Bridge and Highway Overpass, Farrington Highway and Waikele Stream, Waipahu, Honolulu County, HI

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

Kinetic bridges.

DOT National Transportation Integrated Search

1980-01-01

This report on kinetic bridges is essentially a state-of-the-art study on two types of bridges whose location or physical characteristics are designed to be time dependent. The first type, called a "relocatable bridge", is essentially for use as a te...

Bridge health monitoring metrics : updating the bridge deficiency algorithm.

DOT National Transportation Integrated Search

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 ...

Guardrails for use on historic bridges: volume 2--bridge deck overhang design.

DOT National Transportation Integrated Search

2016-11-01

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 bridge...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

1. View of bridge from Interstate 195 (Washington Bridge) looking ...

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

1. View of bridge from Interstate 195 (Washington Bridge) looking southwest - India Point Railroad Bridge, Spanning Seekonk River between Providence & East Providence, Providence, Providence County, RI

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

Treesearch

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...

Cyanide bridged hetero-metallic polymeric complexes: Syntheses, vibrational spectra, thermal analyses and crystal structures of complexes [M(1,2-dmi)2Ni(μ-CN)4]n (M = Zn(II) and Cd(II))

NASA Astrophysics Data System (ADS)

Kürkçüoğlu, Güneş Süheyla; Sayın, Elvan; Şahin, Onur

2015-12-01

Two cyanide bridged hetero-metallic complexes of general formula, [M(1,2-dmi)2Ni(μ-CN)4]n (1,2-dmi = 1,2-dimethylimidazole and M = Zn(II) or Cd(II)) have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal analyses and elemental analyses. The crystallographic analyses reveal that the complexes, [Zn(1,2-dmi)2Ni(μ-CN)4] (1) and [Cd(1,2-dmi)2Ni(μ-CN)4] (2), have polymeric 2D networks. In the complexes, four cyanide groups of [Ni(CN)4]2- coordinated to the adjacent M(II) ions and distorted octahedral geometries of complexes are completed by two nitrogen atoms of trans 1,2-dmi ligands. The structures of 1 and 2 are similar and linked via intermolecular hydrogen bonding, C-H⋯Ni interactions to give rise to 3D networks. Vibration assignments are given for all the observed bands and the spectral features also supported to the crystal structures of heteronuclear complexes. The FT-IR and Raman spectra of the complexes are very much consistent with the structural data presented.

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

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

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

Strong Ferromagnetic Exchange Coupling Mediated by a Bridging Tetrazine Radical in a Dinuclear Nickel Complex.

PubMed

Woods, Toby J; Stout, Heather D; Dolinar, Brian S; Vignesh, Kuduva R; Ballesteros-Rivas, Maria F; Achim, Catalina; Dunbar, Kim R

2017-10-16

The radical bridged compound [(Ni(TPMA)) 2 -μ-bmtz •- ](BF 4 ) 3 ·3CH 3 CN (bmtz = 3,6-bis(2'-pyrimidyl)-1,2,4,5-tetrazine, TPMA = tris(2-pyridylmethyl)amine) exhibits strong ferromagnetic exchange between the S = 1 Ni II centers and the bridging S = 1/2 bmtz radical with J = 96 ± 5 cm -1 (-2J Ni-rad S Ni S rad ). DFT calculations support the existence of strong ferromagnetic exchange.

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

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

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

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

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

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

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

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

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

Giant coercivity and high magnetic blocking temperatures for N 2 3- radical-bridged dilanthanide complexes upon ligand dissociation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demir, Selvan; Gonzalez, Miguel I.; Darago, Lucy E.

Increasing the operating temperatures of single-molecule magnets—molecules that can retain magnetic polarization in the absence of an applied field—has potential implications toward information storage and computing, and may also inform the development of new bulk magnets. Progress toward these goals relies upon the development of synthetic chemistry enabling enhancement of the thermal barrier to reversal of the magnetic moment, while suppressing alternative relaxation processes. Here in this paper, we show that pairing the axial magnetic anisotropy enforced by tetramethylcyclopentadienyl (Cp Me4H) capping ligands with strong magnetic exchange coupling provided by an N 2 3- radical bridging ligand results in amore » series of dilanthanide complexes exhibiting exceptionally large magnetic hysteresis loops that persist to high temperatures. Significantly, reducing the coordination number of the metal centers appears to increase axial magnetic anisotropy, giving rise to larger magnetic relaxation barriers and 100-s magnetic blocking temperatures of up to 20 K, as observed for the complex [K(crypt-222)][(Cp Me4H 2Tb) 2(μ-N∙ 2« less

Giant coercivity and high magnetic blocking temperatures for N 2 3- radical-bridged dilanthanide complexes upon ligand dissociation

DOE PAGES

Demir, Selvan; Gonzalez, Miguel I.; Darago, Lucy E.; ...

2017-12-15

Increasing the operating temperatures of single-molecule magnets—molecules that can retain magnetic polarization in the absence of an applied field—has potential implications toward information storage and computing, and may also inform the development of new bulk magnets. Progress toward these goals relies upon the development of synthetic chemistry enabling enhancement of the thermal barrier to reversal of the magnetic moment, while suppressing alternative relaxation processes. Here in this paper, we show that pairing the axial magnetic anisotropy enforced by tetramethylcyclopentadienyl (Cp Me4H) capping ligands with strong magnetic exchange coupling provided by an N 2 3- radical bridging ligand results in amore » series of dilanthanide complexes exhibiting exceptionally large magnetic hysteresis loops that persist to high temperatures. Significantly, reducing the coordination number of the metal centers appears to increase axial magnetic anisotropy, giving rise to larger magnetic relaxation barriers and 100-s magnetic blocking temperatures of up to 20 K, as observed for the complex [K(crypt-222)][(Cp Me4H 2Tb) 2(μ-N∙ 2« less

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

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

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

Building Bridges to Integrate Care (BRIDGES): Incubating Health Service Innovation across the Continuum of Care for Patients with Multiple Chronic Conditions.

PubMed

Bhattacharyya, Onil; Schull, Michael; Shojania, Kaveh; Stergiopoulos, Vicky; Naglie, Gary; Webster, Fiona; Brandao, Ricardo; Mohammed, Tamara; Christian, Jennifer; Hawker, Gillian; Wilson, Lynn; Levinson, Wendy

2016-01-01

Integrating care for people with complex needs is challenging. Indeed, evidence of solutions is mixed, and therefore, well-designed, shared evaluation approaches are needed to create cumulative learning. The Toronto-based Building Bridges to Integrate Care (BRIDGES) collaborative provided resources to refine and test nine new models linking primary, hospital and community care. It used mixed methods, a cross-project meta-evaluation and shared outcome measures. Given the range of skills required to develop effective interventions, a novel incubator was used to test and spread opportunities for system integration that included operational expertise and support for evaluation and process improvement.

OVERVIEW OF BRIDGES WITH OR&L BRIDGE IN CENTER, WAIKELE CANAL ...

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

OVERVIEW OF BRIDGES WITH OR&L BRIDGE IN CENTER, WAIKELE CANAL BRIDGE IN BACKGROUND. SHOWING THE EARTHEN INCLINE THAT RAISES FARRINGTON HIGHWAY OVER THE FORMER OR&L TRACKS. VIEW FACING SOUTHWEST. - Waikele Canal Bridge and Highway Overpass, Farrington Highway and Waikele Stream, Waipahu, Honolulu County, HI

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

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

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

Ferromagnetic coupling in the three-dimensional malonato-bridged gadoliniumIII complex [Gd2(mal)3(H2O)6] (H2mal = malonic acid).

PubMed

Hernández-Molina, María; Ruiz-Pérez, Catalina; López, Trinidad; Lloret, Francesc; Julve, Miguel

2003-09-08

The novel gadolinium(III) complex of formula [Gd(2)(mal)(3)(H(2)O)(6)] (1) (H(2)mal = 1,3-propanedioic acid) has been prepared and characterized by X-ray diffraction analysis. Crystal data for 1: monoclinic, space group I2/a, a = 11.1064(10) A, b = 12.2524(10) A, c =13.6098(2) A, beta = 92.925(10) degrees, U = 1849.5(3) A(3), Z = 4. Compound 1 is a three-dimensional network made up of malonate-bridged gadolinium(III) ions where the malonate exhibits two bridging modes, eta(5)-bidentate + unidentate and eta(3):eta(3) + bis(unidentate). The gadolinium atom is nine-coordinate with three water molecules and six malonate oxygen atoms from three malonate ligands forming a distorted monocapped square antiprism. The shortest metal-metal separations are 4.2763(3) A [through the oxo-carboxylate bridge] and 6.541(3) A [through the carboxylate in the anti-syn coordination mode]. The value of the angle at the oxo-carboxylate atom is 116.8(2) degrees. Variable-temperature magnetic susceptibility measurements reveal the occurrence of a significant ferromagnetic interaction through the oxo-carboxylate pathway (J = +0.048(1) cm(-1), H = -JS(Gd(1)) x S(Gd(1a))).

5. VAL LAUNCHER BRIDGE OVER LAUNCHER SLAB TAKEN FROM RESERVOIR ...

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

5. VAL LAUNCHER BRIDGE OVER LAUNCHER SLAB TAKEN FROM RESERVOIR LOOKING NORTH. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Investigating vibrational relaxation in cyanide-bridged transition metal mixed-valence complexes using two-dimensional infrared and infrared pump-probe spectroscopies

PubMed Central

Slenkamp, Karla M.; Lynch, Michael S.; Brookes, Jennifer F.; Bannan, Caitlin C.; Daifuku, Stephanie L.; Khalil, Munira

2016-01-01

Using polarization-selective two-dimensional infrared (2D IR) and infrared pump-probe spectroscopies, we study vibrational relaxation of the four cyanide stretching (νCN) vibrations found in [(NH3)5RuIIINCFeII(CN)5]− (FeRu) dissolved in D2O or formamide and [(NC)5FeIICNPtIV(NH3)4NCFeII(CN)5]4− (FePtFe) dissolved in D2O. These cyanide-bridged transition metal complexes serve as models for understanding the role high frequency vibrational modes play in metal-to-metal charge transfers over a bridging ligand. However, there is currently little information about vibrational relaxation and dephasing dynamics of the anharmonically coupled νCN modes in the electronic ground state of these complexes. IR pump-probe experiments reveal that the vibrational lifetimes of the νCN modes are ∼2 times faster when FeRu is dissolved in D2O versus formamide. They also reveal that the vibrational lifetimes of the νCN modes of FePtFe in D2O are almost four times as long as for FeRu in D2O. Combined with mode-specific relaxation dynamics measured from the 2D IR experiments, the IR pump-probe experiments also reveal that intramolecular vibrational relaxation is occurring in all three systems on ∼1 ps timescale. Center line slope dynamics, which have been shown to be a measure of the frequency-frequency correlation function, reveal that the radial, axial, and trans νCN modes exhibit a ∼3 ps timescale for frequency fluctuations. This timescale is attributed to the forming and breaking of hydrogen bonds between each mode and the solvent. The results presented here along with our previous work on FeRu and FePtFe reveal a picture of coupled anharmonic νCN modes where the spectral diffusion and vibrational relaxation dynamics depend on the spatial localization of the mode on the molecular complex and its specific interaction with the solvent. PMID:27158634

Investigating vibrational relaxation in cyanide-bridged transition metal mixed-valence complexes using two-dimensional infrared and infrared pump-probe spectroscopies.

PubMed

Slenkamp, Karla M; Lynch, Michael S; Brookes, Jennifer F; Bannan, Caitlin C; Daifuku, Stephanie L; Khalil, Munira

2016-03-01

Using polarization-selective two-dimensional infrared (2D IR) and infrared pump-probe spectroscopies, we study vibrational relaxation of the four cyanide stretching (νCN) vibrations found in [(NH3)5Ru(III)NCFe(II)(CN)5](-) (FeRu) dissolved in D2O or formamide and [(NC)5Fe(II)CNPt(IV)(NH3)4NCFe(II)(CN)5](4-) (FePtFe) dissolved in D2O. These cyanide-bridged transition metal complexes serve as models for understanding the role high frequency vibrational modes play in metal-to-metal charge transfers over a bridging ligand. However, there is currently little information about vibrational relaxation and dephasing dynamics of the anharmonically coupled νCN modes in the electronic ground state of these complexes. IR pump-probe experiments reveal that the vibrational lifetimes of the νCN modes are ∼2 times faster when FeRu is dissolved in D2O versus formamide. They also reveal that the vibrational lifetimes of the νCN modes of FePtFe in D2O are almost four times as long as for FeRu in D2O. Combined with mode-specific relaxation dynamics measured from the 2D IR experiments, the IR pump-probe experiments also reveal that intramolecular vibrational relaxation is occurring in all three systems on ∼1 ps timescale. Center line slope dynamics, which have been shown to be a measure of the frequency-frequency correlation function, reveal that the radial, axial, and trans νCN modes exhibit a ∼3 ps timescale for frequency fluctuations. This timescale is attributed to the forming and breaking of hydrogen bonds between each mode and the solvent. The results presented here along with our previous work on FeRu and FePtFe reveal a picture of coupled anharmonic νCN modes where the spectral diffusion and vibrational relaxation dynamics depend on the spatial localization of the mode on the molecular complex and its specific interaction with the solvent.

Electronic influences of bridging and chelating diimine ligand coordination in formamidinate-bridged Rh 2 (II,II) dimers

DOE PAGES

White, Travis A.; Dunbar, Kim R.; Thummel, Randolph P.; ...

2015-10-22

We report two new formamidinate-bridged Rh 2 II,II complexes, cis-[Rh 2 II,II(μ-DTolF) 2(μ-np) 2] 2+ (3; DTolF = N,N'-di-p-tolylformamidinate; np = 1,8-naphthyridine) and cis-[Rh 2 II,II(μ-DTolF) 2(κ 2-dap) 2] 2+ (4; dap = 1,12-diazaperylene), were synthesized from cis-[Rh 2 II,II(μ-DTolF) 2(CH 3CN) 6](BF 4) 2 (1), and their properties were compared to those of cis-[Rh 2 II,II(μ-DTolF) 2(phen) 2](BF 4) 2 (2). Density functional theory (DFT) and electrochemical analyses support the description of the highest occupied molecular orbitals (HOMOs) of 3 and 4 as possessing contributions from the metals and formamidinate bridging ligands, with Rh 2/form character, and lowest unoccupiedmore » molecular orbitals (LUMOs) localized on the respective diimine ligand np and dap π* orbitals. Both 3 and 4 display strong, low energy Rh 2/form → diimine(π*) metal/ligand-to-ligand charger transfer ( 1ML–LCT) transitions with maxima at 566 nm (ε = 3600 M -1 cm -1) for 3 and at 630 nm (ε = 2900 M -1 cm -1) for 4 in CH 3CN. Time dependent-DFT (TD-DFT) calculations support these assignments. Finally, the ability of both the bridging np and chelating dap diimine ligands to produce strong absorption of these Rh 2 II,II complexes throughout the visible region is potentially useful for the development of new photocatalysts for H 2 production and photochemotherapeutics.« less

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

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

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

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

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

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

4. View of bridge deck from northeast approach (bridge deck ...

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

4. View of bridge deck from northeast approach (bridge deck from southwest approach is virtually identical - Big Cottonwood River Bridge No. 246, Spanning Big Cottonwood River at Cottonwood Street (City Road No. 165), New Ulm, Brown County, MN

NYSDOT Bridge Deck Task Force evaluation of bridge deck cracking on NYSDOT bridges

DOT National Transportation Integrated Search

2007-02-01

This paper presents a summary of knowledge gained by the NYSDOT Bridge Deck Task Force (BDTF). Although the paper contains recommendations to reduce the prevalence and severity of bridge deck cracking, it does not include a silver bullet soluti...

Hg(ii) and Pd(ii) complexes with a new selenoether bridged biscarbene ligand: efficient mono- and bis-arylation of methyl acrylate with a pincer biscarbene Pd(ii) precatalyst.

PubMed

Rishu; Prashanth, Billa; Bawari, Deependra; Mandal, Ushnish; Verma, Aditya; Choudhury, Angshuman Roy; Singh, Sanjay

2017-05-16

Two equivalents of 1-benzyl-3-bromoethylbenzimidazolium bromide couple with Na 2 Se to produce the first selenoether bridged bis-benzimidazolium salt (LH 2 )Br 2 . The nitrate (LH 2 )(NO 3 ) 2 and tetrafluoroborate (LH 2 )(BF 4 ) 2 salts were also synthesized from (LH 2 )Br 2 . The reaction of Hg(OAc) 2 with (LH 2 )Br 2 gave the first pseudo pincer carbene mercury complex, [Hg(L-κ 2 C)][HgBr 4 ] (C1). Different complexes of Pd(ii) with selenoether bridged carbene were obtained using (LH 2 )Br 2 and (LH 2 )(NO 3 ) 2 . Syntheses of these complexes were dependent on the counter anion and the temperature. Thus, the pincer type ionic complex [PdBr(L-κ 3 CSeC)]Br (C2) was isolated at 80 °C and the pseudo pincer type neutral complex cis-[PdBr 2 (L-κ 2 C)] (C3) was isolated at room temperature from (LH 2 )Br 2 and Pd(OAc) 2 in DMSO. The nitrate precursor (LH 2 )(NO 3 ) 2 on palladation with Pd(OAc) 2 afforded [Pd(L-κ 4 C Bz CSeC)]NO 3 (C4) showing an unprecedented intramolecular metallation at the ortho position of the benzyl wingtip of the benzimidazole moiety. The ligand salts and metal complexes have been characterized using HRMS, heteronuclear NMR and IR spectroscopy. Single crystal X-ray structures of the ligand salts (LH 2 )Br 2 and (LH 2 )(BF 4 ) 2 and complexes C1-C4 have also been elucidated. Complex C2 showed good activity for C-C coupling in the mono-Heck reaction of methyl acrylate and arylbromides. Interestingly, the less common bis-arylation was also observed with deactivated arylbromides as the result of double-Heck coupling.

Development and simulation of microfluidic Wheatstone bridge for high-precision sensor

NASA Astrophysics Data System (ADS)

Shipulya, N. D.; Konakov, S. A.; Krzhizhanovskaya, V. V.

2016-08-01

In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry. This process is based on the “etching in microchannel” technology we developed earlier (doi:10.1088/1742-6596/681/1/012035). Our method ensures a precise control of the flow rate and flow direction in the bridge microchannel. The advantage of our approach is the ability to work without any control valves and other active electronic systems, which are usually used for bridge balancing. The geometrical configuration of microchannels was selected based on the analytical estimations. A detailed 3D numerical model was based on Navier-Stokes equations for a laminar fluid flow at low Reynolds numbers. We investigated the behavior of the Wheatstone bridge under different process conditions; found a relation between the channel resistance and flow rate through the bridge; and calculated the pressure drop across the system under different total flow rates and viscosities. Finally, we describe a high-precision microfluidic pressure sensor that employs the Wheatstone bridge and discuss other applications in complex precision microfluidic systems.

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

Treesearch

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...

The hepatic bridge.

PubMed

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.

[Fe(bpb)(CN)2]- as a versatile building block for the design of novel low-dimensional heterobimetallic systems: synthesis, crystal structures, and magnetic properties of cyano-bridged Fe(III)-Ni(II) complexes [(bpb)(2-) = 1,2-bis(pyridine-2-carboxamido)benzenate].

PubMed

Ni, Zhong-Hai; Kou, Hui-Zhong; Zhao, Yi-Hua; Zheng, Lei; Wang, Ru-Ji; Cui, Ai-Li; Sato, Osamu

2005-03-21

A dicyano-containing [Fe(bpb)(CN)2]- building block has been employed for the synthesis of cyano-bridged heterometallic Ni(II)-Fe(III) complexes. The presence of steric bpb(2-) ligand around the iron ion results in the formation of low-dimensional species: five are neutral NiFe2 trimers and three are one-dimensional (1D). The structure of the 1D complexes consists of alternating [NiL]2+ and [Fe(bpb)(CN)2]- generating a cyano-bridged cationic polymeric chain and the perchlorate as the counteranion. In all complexes, the coordination geometry of the nickel ions is approximately octahedral with the cyano nitrogen atoms at the trans positions. Magnetic studies of seven complexes show the presence of ferromagnetic interaction between the metal ions through the cyano bridges. Variable temperature magnetic susceptibility investigations of the trimeric complexes yield the following J(NiFe) values (based on the spin exchange Hamiltonian H = -2J(NiFe) S(Ni) (S(Fe(1)) + S(Fe(2))): J(NiFe) = 6.40(5), 7.8(1), 8.9(2), and 6.03(4) cm(-1), respectively. The study of the magneto-structural correlation reveals that the cyanide-bridging bond angle is related to the strength of magnetic exchange coupling: the larger the Ni-N[triple bond]C bond angle, the stronger the Ni- - -Fe magnetic interaction. One 1D complex exhibits long-range antiferromagnetic ordering with T(N) = 3.5 K. Below T(N) (1.82 K), a metamagnetic behavior was observed with the critical field of approximately 6 kOe. The present research shows that the [Fe(bpb)(CN)2]- building block is a good candidate for the construction of low-dimensional magnetic materials.

Bridge resource program.

DOT National Transportation Integrated Search

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...

NCDOT : bridge policy

DOT National Transportation Integrated Search

1994-11-01

NCDOTs Bridge Policy establishes controlling design elements for new and reconstructed bridges on the state road system. It includes information to address sidewalks and bicycle facilities on bridges, including minimum handrail heights and sidewal...

Bridged graphite oxide materials

NASA Technical Reports Server (NTRS)

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

2010-01-01

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

50. INTERIOR OF BRIDGE SUSPENSION STRUCTURE ABOVE BRIDGE NOS. 10 ...

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

50. INTERIOR OF BRIDGE SUSPENSION STRUCTURE ABOVE BRIDGE NOS. 10 AND 9 SHOWING CABLE COUNTERWEIGHT SYSTEM AND SCREW-TYPE VERTICAL ADJUSTMENT MACHINERY (LIFTING SCREWS). LOOKING NORTH. - Greenville Yard, Transfer Bridge System, Port of New York/New Jersey, Upper New York Bay, Jersey City, Hudson County, NJ

16. LOG AND PLANK BRIDGE ON ACCESS ROAD NEAR BRIDGE ...

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

16. LOG AND PLANK BRIDGE ON ACCESS ROAD NEAR BRIDGE SITE; SAME STRUCTURE AS SHOWN IN PHOTO #12. ZION NP NEGATIVE NO. 967 ZIO. - Zion-Mount Carmel Highway, Virgin River Bridge, Spanning North Fork of Virgin River on Zion-Mount Carmel Highway, Springdale, Washington County, UT

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

DOT National Transportation Integrated Search

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 ...

Adducin forms a bridge between the erythrocyte membrane and its cytoskeleton and regulates membrane cohesion

PubMed Central

Anong, William A.; Franco, Taina; Chu, Haiyan; Weis, Tahlia L.; Devlin, Emily E.; Bodine, David M.; An, Xiuli; Mohandas, Narla

2009-01-01

The erythrocyte membrane skeleton is the best understood cytoskeleton. Because its protein components have homologs in virtually all other cells, the membrane serves as a fundamental model of biologic membranes. Modern textbooks portray the membrane as a 2-dimensional spectrin-based membrane skeleton attached to a lipid bilayer through 2 linkages: band 3–ankyrin–β-spectrin and glycophorin C–protein 4.1–β-spectrin.1–7 Although evidence supports an essential role for the first bridge in regulating membrane cohesion, rupture of the glycophorin C–protein 4.1 interaction has little effect on membrane stability.8 We demonstrate the existence of a novel band 3–adducin–spectrin bridge that connects the spectrin/actin/protein 4.1 junctional complex to the bilayer. As rupture of this bridge leads to spontaneous membrane fragmentation, we conclude that the band 3–adducin–spectrin bridge is important to membrane stability. The required relocation of part of the band 3 population to the spectrin/actin junctional complex and its formation of a new bridge with adducin necessitates a significant revision of accepted models of the erythrocyte membrane. PMID:19567882

Instrumentation to Aid in Steel Bridge Fabrication : Bridge Virtual Assembly System

DOT National Transportation Integrated Search

2018-05-01

This pool funded project developed a BRIDGE VIRTUAL ASSEMBLY SYSTEM (BRIDGE VAS) that improves manufacturing processes and enhances quality control for steel bridge fabrication. The system replaces conventional match-drilling with virtual assembly me...

IceBridge Data Management and Access Strategies at NSIDC

NASA Astrophysics Data System (ADS)

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

10. PARTIAL VIEW OF SOUTH FACE OF MST AND BRIDGE ...

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

10. PARTIAL VIEW OF SOUTH FACE OF MST AND BRIDGE CRANE MOVED TO ITS SOUTHERN LIMIT - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

11. PARTIAL VIEW OF NORTH FACE OF MST AND BRIDGE ...

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

11. PARTIAL VIEW OF NORTH FACE OF MST AND BRIDGE CRANE MOVED TO ITS NORTHERN LIMIT - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

18. VAL, DETAIL OF LAUNCHER BRIDGE ALONG THE SIDE OF ...

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

18. VAL, DETAIL OF LAUNCHER BRIDGE ALONG THE SIDE OF THE 32' DIAMETER LAUNCHING TUBE LOOKING SOUTHWEST. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

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

DOT National Transportation Integrated Search

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 ...

BRIDGE BUILDER WILLIAM FLINN’S “CAMP & BRIDGE BUILDING OUTFIT”. INTERIOR ...

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

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

Notable unbuilt bridges.

DOT National Transportation Integrated Search

1988-01-01

Described and discussed in this exposition are a number of unusual or notable bridges proposed in this century that for various reasons were not built. Emphasis is placed on bridges in the United States, although some bridges in other countries are a...

21. VAL, DETAIL OF MUZZLE END OF LAUNCHER BRIDGE SHOWING ...

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

21. VAL, DETAIL OF MUZZLE END OF LAUNCHER BRIDGE SHOWING BOTH LAUNCHER TUBES TAKEN FROM RESERVOIR LOOKING NORTH. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Structure-based optimization of salt-bridge network across the complex interface of PTPN4 PDZ domain with its peptide ligands in neuroglioma.

PubMed

Xiao, Xian; He, Qiang-Hua; Yu, Li-Yan; Wang, Song-Qing; Li, Yang; Yang, Hua; Zhang, Ai-Hua; Ma, Xiao-Hong; Peng, Yu-Jie; Chen, Bing

2017-02-01

The PTP non-receptor type 4 (PTPN4) is an important regulator protein in learning, spatial memory and cerebellar synaptic plasticity; targeting the PDZ domain of PTPN4 has become as attractive therapeutic strategy for human neuroglioma. Here, we systematically examined the complex crystal structures of PTPN4 PDZ domain with its known peptide ligands; a number of charged amino acid residues were identified in these ligands and in the peptide-binding pocket of PDZ domain, which can constitute a complicated salt-bridge network across the complex interface. Molecular dynamics (MD) simulations, binding free energy calculations and continuum model analysis revealed that the electrostatic effect plays a predominant role in domain-peptide binding, while other noncovalent interactions such as hydrogen bonds and hydrophobic forces are also responsible for the binding. The computational findings were then used to guide structure-based optimization of the interfacial salt-bridge network. Consequently, five peptides were rationally designed using the high-affinity binder Cyto8-RETEV (RETEV -COOH ) as template, including four single-point mutants (i.e. Cyto8-mtxe 0 : RETEE -COOH , Cyto8-mtxd -1 : RETDV -COOH , Cyto8-mtxd -3 : RDTEV -COOH and Cyto8-mtxk -4 : KETEV -COOH ) and one double-point mutant (i.e. Cyto8-mtxd -1 k -4 : KETDV -COOH ). Binding assays confirmed that three (Cyto8-mtxd -1 , Cyto8-mtxk -4 and Cyto8-mtxd -1 k -4 ) out of the five designed peptides exhibit moderately or considerably increased affinity as compared to the native peptide Cyto8-RETEV. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cyanide-bridged decanuclear cobalt-iron cage.

PubMed

Shiga, Takuya; Tetsuka, Tamaki; Sakai, Kanae; Sekine, Yoshihiro; Nihei, Masayuki; Newton, Graham N; Oshio, Hiroki

2014-06-16

A cyanide-bridged decanuclear [Co6Fe4] cluster was synthesized by a one-pot reaction, and the magnetic properties and electronic configuration were investigated. The complex displayed thermally controlled electron-transfer-coupled spin transition (ETCST) behavior between Co(III) low-spin-NC-Fe(II) low-spin and Co(II) high-spin-NC-Fe(III) low-spin states, as confirmed by single-crystal X-ray, magnetic, and Mössbauer analyses.

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

Treesearch

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...

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

ERIC Educational Resources Information Center

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…

Mono- and binuclear molybdenum and tungsten complexes containing asymmetric bridging ligands: Effects of ligand conjugation and conformation on metal-metal interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, A.; Jeffery, J.C.; Maher, J.P.

The authors have prepared the new monodentate ligands 4-(4-methoxyphenyl)pyridine, 1-(4-pyridyl)-2-(4-methoxyphenyl)ethene, 1-(4-pyridyl)-2-(3-methoxyphenyl)ethene, and 1-(3-pyridyl)-2-(4-methoxyphenyl)ethene (L[sup 5]-L[sup 8]); demethylation of the methoxy group in each case afforded the new bridging bidentate ligands HL[sup 1]-HL[sup 4], which contain one pyridyl and one phenolate donor. Attachment of a MoL*(NO)Cl [L* = hydrotris(3,5-dimethylpyrazolyl)borate] moiety to the pyridyl groups of L[sup 5]-L[sup 8] gave the 17-electron complexes [Mo(NO)L*ClL[prime

Salt-bridge networks within globular and disordered proteins: characterizing trends for designable interactions.

PubMed

Basu, Sankar; Mukharjee, Debasish

2017-07-01

There has been considerable debate about the contribution of salt bridges to the stabilization of protein folds, in spite of their participation in crucial protein functions. Salt bridges appear to contribute to the activity-stability trade-off within proteins by bringing high-entropy charged amino acids into close contacts during the course of their functions. The current study analyzes the modes of association of salt bridges (in terms of networks) within globular proteins and at protein-protein interfaces. While the most common and trivial type of salt bridge is the isolated salt bridge, bifurcated salt bridge appears to be a distinct salt-bridge motif having a special topology and geometry. Bifurcated salt bridges are found ubiquitously in proteins and interprotein complexes. Interesting and attractive examples presenting different modes of interaction are highlighted. Bifurcated salt bridges appear to function as molecular clips that are used to stitch together large surface contours at interacting protein interfaces. The present work also emphasizes the key role of salt-bridge-mediated interactions in the partial folding of proteins containing long stretches of disordered regions. Salt-bridge-mediated interactions seem to be pivotal to the promotion of "disorder-to-order" transitions in small disordered protein fragments and their stabilization upon binding. The results obtained in this work should help to guide efforts to elucidate the modus operandi of these partially disordered proteins, and to conceptualize how these proteins manage to maintain the required amount of disorder even in their bound forms. This work could also potentially facilitate explorations of geometrically specific designable salt bridges through the characterization of composite salt-bridge networks. Graphical abstract ᅟ.

Exact Solution for Capillary Bridges Properties by Shooting Method

NASA Astrophysics Data System (ADS)

Qiang-Nian, Li; Jia-Qi, Zhang; Feng-Xi, Zhou

2017-04-01

The investigation of liquid bridge force acting between wet particles has great significance in many fields. In this article, the exact solution of capillary force between two unequal-sized spherical particles is investigated. Firstly, The Young-Laplace equation with moving boundary is converted into a set of ordinary differential equations with two fix point boundary using variable substitution technique, in which the gravity effects have been neglected. The geometry of the liquid bridge between two particles is solved by shooting method. After that, the gorge method is applied to calculate the capillary-bridge force that is consists of contributions from the capillary suction and surface tension. Finally, the effect of various parameters including distance between two spheres, radii of spheres, and contact angles on the capillary force are investigated. It is shown that the presented approach is an efficient and accurate algorithm for capillary force between two particles in complex situations.

A rectangular Ni-Fe cluster with unusual cyanide bridges.

PubMed

Krüger, Christoph; Sato, Hiroki; Matsumoto, Takuto; Shiga, Takuya; Newton, Graham N; Renz, Franz; Oshio, Hiroki

2012-10-07

An asymmetric polycyanide iron complex, K(2)[Fe(III)(L1)(CN)(4)](MeOH) (HL1 = 2,2'-(1H-pyrazole-3,5-diyl)bis-pyridine), was synthesized and its complexation compatibility with nickel ions was examined. Two kinds of enantiomeric nickel-iron squares were obtained in the presence of a chiral bidentate capping ligand. The compounds display unusual cyanide bridge geometry and have ferromagnetic interactions between nickel and iron ions.

Parryville Bridge (S.R. 2008, section 01B Bridge) looking north across ...

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

Parryville Bridge (S.R. 2008, section 01B Bridge) looking north across traffic level, showing village of Parryville. - Parryville Bridge, State Route 2008 over Pohapoco Creek, Parryville, Carbon County, PA

DETAIL VIEW OF BRIDGE CRANE USED TO LIFT DOMED LIDS ...

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

DETAIL VIEW OF BRIDGE CRANE USED TO LIFT DOMED LIDS OF THE ALTITUDE CHAMBERS, FACING SOUTHWEST - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

4. VAL PARTIAL ELEVATION SHOWING LAUNCHER BRIDGE ON SUPPORTS, LAUNCHER ...

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

4. VAL PARTIAL ELEVATION SHOWING LAUNCHER BRIDGE ON SUPPORTS, LAUNCHER SLAB, SUPPORT CARRIAGE, CONCRETE 'A' FRAME STRUCTURE AND CAMERA TOWER LOOKING SOUTHEAST. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

A Novel Pentadentate Coordination Mode for the Carbonato Bridge: Synthesis, Crystal Structure, and Magnetic Behavior of (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)], a New Trinuclear Nickel(II) Carbonato-Bridged Complex with Strong Antiferromagnetic Coupling.

PubMed

Escuer, Albert; Vicente, Ramon; Kumar, Sujit B.; Solans, Xavier; Font-Bardía, Mercé; Caneschi, Andrea

1996-05-22

The trinuclear complex (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)] was obtained by reaction of basic solutions of nickel(II), Medpt (bis(3aminopropyl)methylamine) and thiocyanate ligand with atmospheric CO(2) or by simple reaction with carbonate anion. (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)] crystallizes in the triclinic system, space group P&onemacr;, with a = 12.107(5) Å, b = 12.535(7) Å, c = 16.169(9) Å, alpha = 102.69(5) degrees, beta = 92.91(5) degrees, gamma = 118.01(4) degrees, Z = 2, and R = 0.043. The three nickel atoms are asymmetrically bridged by one pentadentate carbonato ligand, which shows a novel coordination mode. The (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)] compound shows a very strong antiferromagnetic coupling. Fit as irregular triangular arrangement gave J(1) = -88.4, J(2) = -57.7, and J(3) = -9.6 cm(-)(1), which is the strongest AF coupling observed to date for Ni(3) compounds. The magnetic behavior of the carbonato bridge is discussed.

Hirschsprung's disease: A bridge for science and surgery.

PubMed

Tam, Paul K H

2016-01-01

Understanding the true nature of the disease provided the basis for appropriate surgery for Hirschsprung's disease some 60 years ago. Nevertheless, surgical outcome remains unsatisfactory. Advances in diagnosis and treatment will depend on the elucidation of the pathogenesis and disease heterogeneity. This lecture outlines the author's attempt in the past 30 years to bridge some of the gaps of knowledge in Hirschsprung's disease. Studies of human fetal gut and aganglionic gut gave insight into the complexity of the human enteric nervous system, but the more fruitful studies came from genetic studies in which disease-causing genes were discovered, and the importance of noncoding mutations conferring disease susceptibility was unraveled. Animal models and pluripotent stem cell studies allowed elucidation of the interacting gene-cell-microenvironment signaling pathways for neural crest proliferation, migration, and differentiation. Hirschsprung's disease has been a bridge for science and surgery. An integrative approach could provide breakthroughs in the diagnosis and treatment strategies of this complex condition, leading to improved outcome. Copyright © 2016 Elsevier Inc. All rights reserved.

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

DOT National Transportation Integrated Search

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...

Pre-Elsonian mafic magmatism in the Nain Igneous Complex, Labrador: the bridges layered intrusion

USGS Publications Warehouse

Ashwal, L.D.; Wiebe, R.A.; Wooden, J.L.; Whitehouse, M.J.; Snyder, Diane

1992-01-01

Decades of work on the pristine, unmetamorphosed, and well exposed anorthositic, mafic and granitic rocks of the Nain igneous complex, Labrador, have led to the conclusion that all plutonic rocks in that area were emplaced in a short time intercal at about 1300 ?? 10 Ma). We report here new isotopic data for mafic intrusive rocks that appear to have crystallized several hundred Ma earlier than the bulk of the plutonic activity in the Nain complex. The Bridges layered intrusion (BLI) is a small (15-20 km2) lens of layered mafic rocks about 1.5 km thick, surrounded and intruded by anorthositic, leuconoritic and leucotroctolitic plutons in the middle of the coastal section of the Nain igneous complex. BLI shows very well developed magmatic structures, including channel scours, slump structures, and ubiquitous modally graded layering. Most rocks, however, show granular textures indicative of recrystallization, presumably caused by emplacement of younger anorthositic rocks. BLI contains cumulate rocks with slightly more primitive mineral compositions (An60-83, Fo66-71) than those of other mafic intrusions in the Nain igneous complex, including Kiglapait. SmNd isotopic data for 7 BLI whole-rocks ranging in composition between olivine melagabbro and olivine leucogabbro yield an age of 1667 ?? 75 Ma, which we interpret as the time of primary crystallization. The internal isotopic systematics of the BLI have been reset, probably by intrusion of adjacent anorthositic plutons. A SmNd mineral isochron (plag, whole-rock, mafics) for a BLI olivine melagabbro gives an age of 1283 ?? 22 Ma, equivalent within error of a mineral array (plag, whole-rock, opx, cpx) for an adjacent, igneous-textured, leuconorite vein (1266 ?? 152 Ma). The initial Nd ratio for BLI corresponds to ??{lunate}Nd = -3.18 ?? 0.44. Other whole-rock samples, however, some with vein-like alteration (Chlorite, serpentine, amphiboles), show ??{lunate}Nd values as low as -9.1, suggesting variable contamination by

Dynamic response of the train-track-bridge system subjected to derailment impacts

NASA Astrophysics Data System (ADS)

Ling, Liang; Dhanasekar, Manicka; Thambiratnam, David P.

2018-04-01

Derailments on bridges, although not frequent, when occurs due to a complex dynamic interaction of the train-track-bridge structural system, are very severe. Furthermore, the forced vibration induced by the post-derailment impacts can toss out the derailed wagons from the bridge deck with severe consequences to the traffic underneath and the safety of the occupants of the wagons. This paper presents a study of the train-track-bridge interaction during a heavy freight train crossing a concrete box girder bridge from a normal operation to a derailed state. A numerical model that considers the bridge vibration, train-track interaction and the train post-derailment behaviour is formulated based on a coupled finite-element - multi-body dynamics (FE-MBD) theory. The model is applied to predict the post-derailment behaviour of a freight train composed of one locomotive and several wagons, as well as the dynamic response of a straight single-span simply supported bridge containing ballast track subjected to derailment impacts. For this purpose, a typical derailment scenario of a heavy freight train passing over a severe track geometry defect is introduced. The dynamic derailment behaviour of the heavy freight train and the dynamic responses of the rail bridge are illustrated through numerical examples. The results exhibit the potential for tossing out of the derailed trains from the unstable increase in the yaw angle signature and a lower rate of increase of the bridge deck bending moment compared to the increase in the static axle load of the derailed wheelset.

cis-2,2'-Bipyrimidine-bridged polynuclear complex: a stairway-like mixed-valent {Fe(4)} cluster.

PubMed

Alborés, Pablo; Rentschler, Eva

2010-10-04

We report the first example of a polynuclear discrete coordination compound exhibiting only bpym bridges and containing a first-row d transition metal. A smooth self-assembly one-pot synthetic route, starting from simply FeCl(2) and FeCl(3) hydrates, allowed us to prepare a tetranuclear Fe(4) cluster with a stairway-like structure and the formula cis-{[(H(2)O)Cl(3)Fe(III)-μ(bpym)Fe(II)Cl(2)]}(2)-μ(bpym) (1) . All spectroscopic data suggest that complex 1 is a valence-localized mixed-valent Fe(II)-Fe(III) cluster with typical Mössbauer lines for both sites, which do not change with temperature. Reflectance spectroscopy did not allow one to distinguish an intervalence charge-transfer band. However, time-dependent density functional theory (DFT) calculations predict a weak high-energy Fe(II) → Fe(III) transition. Regarding the magnetic properties, the high-spin Fe(II) and Fe(III) ions interact in a weakly antiferromagnetic way with isotropic J constants of only a few wavenumbers as derived from direct-current susceptibility and magnetization data. Broken-symmetry DFT calculations support these observations.

Acquisition and Analysis of Dynamic Responses of a Historic Pedestrian Bridge using Video Image Processing

NASA Astrophysics Data System (ADS)

O'Byrne, Michael; Ghosh, Bidisha; Schoefs, Franck; O'Donnell, Deirdre; Wright, Robert; Pakrashi, Vikram

2015-07-01

Video based tracking is capable of analysing bridge vibrations that are characterised by large amplitudes and low frequencies. This paper presents the use of video images and associated image processing techniques to obtain the dynamic response of a pedestrian suspension bridge in Cork, Ireland. This historic structure is one of the four suspension bridges in Ireland and is notable for its dynamic nature. A video camera is mounted on the river-bank and the dynamic responses of the bridge have been measured from the video images. The dynamic response is assessed without the need of a reflector on the bridge and in the presence of various forms of luminous complexities in the video image scenes. Vertical deformations of the bridge were measured in this regard. The video image tracking for the measurement of dynamic responses of the bridge were based on correlating patches in time-lagged scenes in video images and utilisinga zero mean normalisedcross correlation (ZNCC) metric. The bridge was excited by designed pedestrian movement and by individual cyclists traversing the bridge. The time series data of dynamic displacement responses of the bridge were analysedto obtain the frequency domain response. Frequencies obtained from video analysis were checked against accelerometer data from the bridge obtained while carrying out the same set of experiments used for video image based recognition.

Acquisition and Analysis of Dynamic Responses of a Historic Pedestrian Bridge using Video Image Processing

NASA Astrophysics Data System (ADS)

O'Byrne, Michael; Ghosh, Bidisha; Schoefs, Franck; O'Donnell, Deirdre; Wright, Robert; Pakrashi, Vikram

2015-07-01

Video based tracking is capable of analysing bridge vibrations that are characterised by large amplitudes and low frequencies. This paper presents the use of video images and associated image processing techniques to obtain the dynamic response of a pedestrian suspension bridge in Cork, Ireland. This historic structure is one of the four suspension bridges in Ireland and is notable for its dynamic nature. A video camera is mounted on the river-bank and the dynamic responses of the bridge have been measured from the video images. The dynamic response is assessed without the need of a reflector on the bridge and in the presence of various forms of luminous complexities in the video image scenes. Vertical deformations of the bridge were measured in this regard. The video image tracking for the measurement of dynamic responses of the bridge were based on correlating patches in time-lagged scenes in video images and utilisinga zero mean normalised cross correlation (ZNCC) metric. The bridge was excited by designed pedestrian movement and by individual cyclists traversing the bridge. The time series data of dynamic displacement responses of the bridge were analysedto obtain the frequency domain response. Frequencies obtained from video analysis were checked against accelerometer data from the bridge obtained while carrying out the same set of experiments used for video image based recognition.

Designing timber bridge superstructures : a comparison of U.S. and Canadian bridge codes.

Treesearch

James Scott Groenier; James P. Wacker

2008-01-01

Several changes relating to timber bridges have been incorporated into the AASHTO-LRFD Bridge Design Specifications recently. In addition, the Federal Highway Administration is strongly encouraging an LRFD-based design approach for all new bridges in the United States. The Bridge Design Code in Canada was one of the first to adopt the limit states design philosophy,...

Synthesis and crystallographic characterization of a mononuclear cobalt(III) complex possessing both thiol­ate and thio­ether donors: reactivity of an thiol­ate-bridged penta­nuclear Co2Ag3 complex with iodo­methane

PubMed Central

Fukuda, Yosuke; Yoshinari, Nobuto; Konno, Takumi

2017-01-01

Treatment of an S-bridged penta­nuclear AgI 3CoIII 2 complex, [Ag3{Co(L)}2]3+ [L 3– = N(CH2NHCH2CH2S−)3], in which two tris­(thiol­ate)-type mononuclear CoIII units ([Co(L)]) are bridged by three AgI ions through S atoms, with iodo­methane (CH3I) gave a new CoIII mononuclear complex, [Co(LMe2)]2+ [LMe2 − = N(CH2NHCH2CH2S−)(CH2NHCH2CH2SCH3)2], systematic name: {2-[(bis{[2-(methylsulfanyl)ethyl]aminomethyl}aminomethyl)amino]ethanethiolato}cobalt(III) bis(hexafluoridophosphate). This cationic complex was crystallized with PF6 − anions to form the title compound, [Co(LMe2)](PF6)2. In the [Co(LMe2)]2+ cation, two of three thiol­ate groups in [Co(L)] are methyl­ated while one thiol­ate group remains unreacted. Although a total of eight stereoisomers are possible for [Co(LMe2)]2+, only a pair of enanti­omers {ΛRR- and ΔSS-[Co(LMe2)]2+} are selectively formed. In the crystal, the complex cations and the PF­6 − anions are connected through weak N—H⋯F, C—H⋯F and C—H⋯S hydrogen bonds into a three-dimensional structure. Two F atoms in one PF6 anion are disordered over two sets of sites with refined occupancies of 0.61 (4) and 0.39 (4) and two F atoms in the other PF6 − anion are disordered over two sets of sites with occupancies of 0.5. PMID:28529774

Field Performance of Timber Bridges. 16: North Siwell Road Stress-Laminated Bridge

DOT National Transportation Integrated Search

1998-03-01

This report is 16th in a series of reports that documents the : field performance of timber bridges. The North Siwell Road bridge was constructed during December 1994 in Hinds County, Mississippi. The bridge is a single span, stress laminated T-beam ...

Performance Assessment of Bridges Using GPS: The Juarez Bridge in Culiacan, Mexico

NASA Astrophysics Data System (ADS)

Vazquez, G. E.; Gaxiola-Camacho, J. R.; Trejo, M.; Echagaray, J.; Guzman, G. M.

2015-12-01

Performance assessment of bridges has become very important during recent years. Bridges around the world are aging, leading to the incorporation of efficient, reliable, and economic evaluation procedures. These techniques must assess properly the performance of bridges under several loading conditions in a real manner, representing the physics of the problem. Among several approaches, Global Positioning System (GPS) can be intelligently used for the performance evaluation of bridges. We focused on GPS, since it naturally produces position estimates as compared to seismic instruments that record either velocity or acceleration, and thus require an integration. There are several reasons that make the Juarez Bridge a case of study for evaluation: it is approximately 45 years old, it is a reinforced concrete structure, it connects two significant zones of the city, and its spans is closely to 200 meters long. In addition, thousands of vehicles and pedestrians use the Juarez Bridge every day, which make feasible the GPS performance assessment. Hence, in order to produce optimal position estimates, GPS data were collected during two consecutive hours at three different periods of the day for a whole week (Monday through Sunday), to represent three critical limit states of the bridge (mid-span and end-spans). GPS data were processed using the GAMIT/GLOBK software, considering 1-second sampling rate, 15-degree cutoff angle, ionosphere-free double-differenced (DD) carrier phase method, and precise final orbits disseminated by IGS (International GNSS Service). The displacements obtained from the above discussed procedure are compared with allowable values documented in bridge construction manuals. Reliability theory was used to evaluate the probability of failure of the bridge for the three periods of the day. In addition, a conclusion was made about the most risky day of the week for the use of the Juarez Bridge. It is expected that the results from the proposed research

1,5-Diamido-9,10-anthraquinone, a Centrosymmetric Redox-Active Bridge with Two Coupled β-Ketiminato Chelate Functions: Symmetric and Asymmetric Diruthenium Complexes.

PubMed

Ansari, Mohd Asif; Mandal, Abhishek; Paretzki, Alexa; Beyer, Katharina; Fiedler, Jan; Kaim, Wolfgang; Lahiri, Goutam Kumar

2016-06-06

The dinuclear complexes {(μ-H2L)[Ru(bpy)2]2}(ClO4)2 ([3](ClO4)2), {(μ-H2L)[Ru(pap)2]2}(ClO4)2 ([4](ClO4)2), and the asymmetric [(bpy)2Ru(μ-H2L)Ru(pap)2](ClO4)2 ([5](ClO4)2) were synthesized via the mononuclear species [Ru(H3L)(bpy)2]ClO4 ([1]ClO4) and [Ru(H3L)(pap)2]ClO4 ([2]ClO4), where H4L is the centrosymmetric 1,5-diamino-9,10-anthraquinone, bpy is 2,2'-bipyridine, and pap is 2-phenylazopyridine. Electrochemistry of the structurally characterized [1]ClO4, [2]ClO4, [3](ClO4)2, [4](ClO4)2, and [5](ClO4)2 reveals multistep oxidation and reduction processes, which were analyzed by electron paramagnetic resonance (EPR) of paramagnetic intermediates and by UV-vis-NIR spectro-electrochemistry. With support by time-dependent density functional theory (DFT) calculations the redox processes could be assigned. Significant results include the dimetal/bridging ligand mixed spin distribution in 3(3+) versus largely bridge-centered spin in 4(3+)-a result of the presence of Ru(II)-stabilizig pap coligands. In addition to the metal/ligand alternative for electron transfer and spin location, the dinuclear systems allow for the observation of ligand/ligand and metal/metal site differentiation within the multistep redox series. DFT-supported EPR and NIR absorption spectroscopy of the latter case revealed class II mixed-valence behavior of the oxidized asymmetric system 5(3+) with about equal contributions from a radical bridge formulation. In comparison to the analogues with the deprotonated 1,4-diaminoanthraquinone isomer the centrosymmetric H2L(2-) bridge shows anodically shifted redox potentials and weaker electronic coupling between the chelate sites.

At the Borderline between Metal-Metal Mixed Valency and a Radical Bridge Situation: Four Charge States of a Diruthenium Complex with a Redox-Active Bis( mer-tridentate) Ligand.

PubMed

Mondal, Sudipta; Schwederski, Brigitte; Frey, Wolfgang; Fiedler, Jan; Záliš, Stanislav; Kaim, Wolfgang

2018-04-02

The complex ions [L 3 Ru(μ,η 3 :η 3 -BL)RuL 3 ] n+ (1 n+ , L 3 = 4,4',4″-tri- tert-butyl-2,6,2',6″-terpyridine and H 2 BL 2- = 1,2-bis(salicyloyl)hydrazide(2-)) were isolated with PF 6 - or ClO 4 - counterions ( n = 1) and as bis(hexafluorophosphate) ( n = 2). Structural, electrochemical, and spectroscopic characterization reveals the monocation as intermediate ( K c = 10 8.2 ) in the three-step reversible redox system 1 0/+/2+/3+ . The 1 + ion has the molecule-bridged (Ru- - -Ru 4.727 Å) ruthenium centers involved in five- and six-membered chelate rings, and it exhibits long-wavelength absorptions at λ max 2240, 1660, and 1530 nm (ε max = 1000, 3000, and 8000 M -1 cm -1 , respectively), which would be compatible with a Ru III Ru II mixed-valent situation or with a coordinated radical ion bridge. In fact, EPR and DFT analysis of 1 + reveals that the spin is equally distributed over the ligand bridge and over both metals. The oxidized paramagnetic ions 1 2+ and 1 3+ have been studied by 1 H NMR and EPR and by TD-DFT supported UV-vis-NIR and MIR (mid-IR) spectroelectrochemistry. The capacity of various kinds of bis( mer-tridentate) bridging ligands (π donors or π acceptors, cyclometalated or noncyclometalated) for mediating metal-metal interactions is discussed.

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

Treesearch

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...

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

Treesearch

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...

Improving bridge load rating accuracy.

DOT National Transportation Integrated Search

2013-06-01

Nearly one-quarter of Alabamas bridges are deemed structurally deficient or functionally obsolete. An : additional seven percent of Alabamas bridges were posted bridges in 2010. (Federal Highway Administration, : 2011) Accurate bridge load rati...

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

NASA Astrophysics Data System (ADS)

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.

GENERAL VIEW OF THE BRIDGE CRANE USED IN HB3 AND ...

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

GENERAL VIEW OF THE BRIDGE CRANE USED IN HB-3 AND HB-4, FACING SOUTHEAST - Cape Canaveral Air Force Station, Launch Complex 39, Vehicle Assembly Building, VAB Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

9. COMPLETED ROLLING CAMERA CAR ON RAILROAD TRACK AND BRIDGE ...

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

9. COMPLETED ROLLING CAMERA CAR ON RAILROAD TRACK AND BRIDGE LOOKING WEST, APRIL 26, 1948. (ORIGINAL PHOTOGRAPH IN POSSESSION OF DAVE WILLIS, SAN DIEGO, CALIFORNIA.) - Variable Angle Launcher Complex, Camera Car & Track, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

74. DETAIL VIEW OF INSIDE THE LAUNCHING BRIDGE LOOKING SOUTHWEST ...

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

74. DETAIL VIEW OF INSIDE THE LAUNCHING BRIDGE LOOKING SOUTHWEST SHOWING ADJUSTABLE STAIRS ON THE LEFT AND LAUNCHING TUBE ON THE RIGHT, Date unknown, circa 1948. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

BRIDGES: Evolution of basic and applied linkages in benthic science

USGS Publications Warehouse

Aumen, Nicholas G.; Gurtz, Martin E.; Barbour, Michael T.; Moerke, Ashley

2010-01-01

Growing awareness of environmental degradation resulted in stricter environmental regulations and laws for aquatic ecosystems. These regulations were followed by an increase in applied research and monitoring beginning in the early 1970s. The number of applied scientists who were members of the North American Benthological Society grew at a commensurate rate. The editors of J-NABS recognized that, despite these increases, submitted manuscripts mostly addressed basic science. In response, the BRIDGES section of J-NABS was created in 1994 to provide a forum for linking basic ecological principles to applied science problems and issues. We examined the emergence of applied science topics in J-NABS and its predecessor, Freshwater Invertebrate Biology, from their beginning in 1982 to 2009. We classified papers among 11 categories that included a basic/applied science linkage. In the 1980s, applied papers were predominantly on effects of eutrophication/pollution and landuse changes. When BRIDGES was established in 1994, papers were solicited by editors and BRIDGES sections usually included >1 paper on a common theme to express complementary or alternate viewpoints. Forty-two papers appeared in BRIDGES between 1994 and 2009, but the number per issue declined after 2001. The total number of applied science papers in J-NABS has increased since ∼1994. Citation analysis of BRIDGES papers illustrates how information is being cited, but applied papers often are used in ways that might not lead to citations. BRIDGES transitioned to a new format in September 2009 to address new types of complex, multifaceted linkages. All new BRIDGES articles will be open access, and authors will be encouraged to produce lay-language fact sheets and to post them on the web.

DETAIL VIEW OF THE BRIDGE CRANE HOOKS USED IN HB3 ...

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

DETAIL VIEW OF THE BRIDGE CRANE HOOKS USED IN HB-3 AND HB-4, FACING SOUTHWEST - Cape Canaveral Air Force Station, Launch Complex 39, Vehicle Assembly Building, VAB Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

Curriculum and Popular Culture: Building Bridges and Making Waves.

ERIC Educational Resources Information Center

Morrell, Ernest

This paper explores the potential of incorporating elements of popular culture such as music, film, and court trials as a bridge to help students traditionally alienated by the canonical texts they confront in the "standard" curriculum to conquer and gain a critical understanding of those texts. Sometimes complex, canonical texts can be…

Development of bridge girder movement criteria for accelerated bridge construction.

DOT National Transportation Integrated Search

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. ...

Diode-quad bridge circuit means

NASA Technical Reports Server (NTRS)

Harrison, D. R.; Dimeff, J. (Inventor)

1975-01-01

Diode-quad bridge circuit means is described for use as a transducer circuit or as a discriminator circuit. It includes: (1) a diode bridge having first, second, third, and fourth bridge terminals consecutively coupled together by four diodes polarized in circulating relationship; (2) a first impedance connected between the second bridge terminal and a circuit ground; (3) a second impedance connected between the fourth bridge terminal and the circuit ground; (4) a signal source having a first source terminal capacitively coupled to the first and third bridge terminals, and a second source terminal connected to the circuit ground; and (5) an output terminal coupled to the first bridge terminal and at which an output signal may be taken.

Hydraulic risk assessment of bridges using UAV photogrammetry

NASA Astrophysics Data System (ADS)

Hackl, Jürgen; Adey, Bryan T.; Woźniak, Michał; Schümperlin, Oliver

2017-04-01

investigated includes: the use of geo-referenced images, taken by an UAV, the exportation of these images into a photogrammetric software, the creation of a 3D mesh of the terrain from these images, the conversion of the 3D mesh to a computational mesh, the use of the computational mesh to build a hydrodynamic model, and the use of the hydrodynamic model to run flow simulations. The process was used to estimate the complex water flow near a single span concrete bridge in the Canton of Grisons, Switzerland. The hydraulic events (abutment scour and overflow) predicted by the developed model were compared with with historical observations from a recent flood event in the region. The hydraulic events predicted by the developed model correspond with historical observations, indicating that the topological information collected in this way is sufficiently accurate to be used to simulate complex flow situations, which can be used in bridge risk assessments. Hackl, J., Adey, B.T., Heitzler, M., and Iosifescu Enescu, I. (2015). "An Overarching Risk Assessment Process to Evaluate the Risks Associated with Infrastructure Networks due to Natural Hazards." International Journal of Performability Engineering, 11(2), 153-168. Adey, B.T., Hackl, J., Lam, J.C., van Gelder, P., Prak, P., van Erp, N., Heitzler, M., Iosifescu Enescu, I., and Hurni, L. (2016). "Ensuring acceptable levels of infrastructure related risks due to natural hazards with emphasis on conducting stress tests." 1st International Symposium on Infrastructure Asset Management (SIAM2016), K. Kobayashi, ed., Kyoto, Japan, 19-29 (Jan).

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

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

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

Probing the inner space of salt-bridged calix[5]arene capsules.

PubMed

Brancatelli, Giovanna; Gattuso, Giuseppe; Geremia, Silvano; Notti, Anna; Pappalardo, Sebastiano; Parisi, Melchiorre F; Pisagatti, Ilenia

2014-05-02

A combined DOSY and XRD study indicates that a carboxylcalix[5]arene receptor is able to encapsulate α,ω-diamines of appropriate length by means of a proton-transfer-mediated recognition process followed by salt-bridge-assisted bis-endo-complexation.

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

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

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

2. DETAIL OF KLINGLE ROAD BRIDGE AND PATHWAY BRIDGE CROSSINGS. ...

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

2. DETAIL OF KLINGLE ROAD BRIDGE AND PATHWAY BRIDGE CROSSINGS. AERIAL VIEW OF BEACH DRIVE AT INTERSECTION OF KLINGLE ROAD AND PORTER STREET. VIEW NE. - Rock Creek Park Road System, Washington, District of Columbia, DC

Experimental and analytical investigations of the piles and abutments of integral bridges.

DOT National Transportation Integrated Search

2002-01-01

This research investigated, through experimental and analytical studies, the complex interactions that take place between the structural components of an integral bridge and the adjoining soil. The ability of piles and abutments to withstand thermall...

Load ratings for secondary bridges.

DOT National Transportation Integrated Search

1991-05-01

A load rating states the load in tons which a vehicle can impose on a bridge. : Changes in guidelines, standards, and customary uses of bridges require : analyses of bridges to be updated and re-evaluated. : In this report, twenty-two secondary bridg...

Controlled synthesis of racemic indenyl rare-earth metal complexes via the cooperation between the intramolecular coordination of donor atoms and a bridge.

PubMed

Zhou, Shuangliu; Wu, Zhangshuan; Zhou, Lingmin; Wang, Shaowu; Zhang, Lijun; Zhu, Xiancui; Wei, Yun; Zhai, Jinhua; Wu, Jie

2013-06-03

The reactions of Me2Si(C9H6CH2CH2-DG)2 (DG = NMe2 (1), CH2NMe2 (2), OMe (3), and N(CH2CH2)2O (4)) with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 in toluene afforded a series of racemic divalent rare-earth metal complexes: {η(5):η(1):η(5):η(1)-Me2Si(C9H5CH2CH2-DG)2}RE (DG = NMe2, RE = Yb (6) and Eu (7); DG = CH2NMe2, RE = Yb (8), Eu (9), and Sm (10); DG = OMe, RE = Yb (11) and Eu (12); DG = N(CH2CH2)2O, RE = Yb (13) and Eu (14)). Similarly, the racemic divalent rare-earth metal complexes {η(5):η(1):η(5):η(1)-Me2Si(C9H5CH2CH2CH2NMe2)(C9H5CH2CH2OMe)}RE (RE = Yb (15) and Eu (16)) were also obtained. The reaction of Me2Si(C9H5CH2CH2OMe)2Li2 with NdCl3 gave a racemic dimeric neodymium chloride {η(5):η(1):η(5)-Me2Si(C9H5CH2CH2OMe)2NdCl}2 (17), whereas the reaction of Me2Si(C9H5CH2CH2NMe2)2Li2 with SmCl3 afforded a racemic dinuclear samarium chloride bridged by lithium chloride {η(5):η(1):η(5):η(1)-Me2Si(C9H5CH2CH2NMe2)2SmCl}2(μ-LiCl) (18). Further reaction of complex 18 with LiCH2SiMe3 provided an unexpected rare-earth metal alkyl complex {η(5):η(1):η(5):η(1):σ-Me2Si(C9H5CH2CH2NMe2)[(C9H5CH2CH2N(CH2)Me]}Sm (19) through the activation of an sp(3) C-H bond α-adjacent to the nitrogen atom. Complexes 19 and {η(5):η(1):η(5):η(1):σ-Me2Si(C9H5CH2CH2NMe2)[(C9H5CH2CH2N(CH2)Me]}Y (20) were also obtained by one-pot reactions of Me2Si(C9H5CH2CH2NMe2)2Li2 with RECl3 followed by treatment with LiCH2SiMe3. All compounds were fully characterized by spectroscopic methods and elemental analysis. Complexes 6-10 and 14-20 were further characterized by single-crystal X-ray diffraction analysis. All of the prepared rare-earth metal complexes were racemic, suggesting that racemic organo rare-earth metal complexes could be controllably synthesized by the cooperation between a bridge and the intramolecular coordination of donor atoms.

Akashi Kaikyo Bridge, Japan

NASA Image and Video Library

2013-03-25

NASA Terra spacecraft shows the Akashi Kaikyo Bridge or Pearl Bridge, the longest central span of any suspension bridge in the world, at 1991 meters, connecting the city of Kobe, Japan with Iwaja on Awaji Island by crossing the busy Akashi Strait.

Morphological aspects of myocardial bridges.

PubMed

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

Treesearch

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...

Theoretical study of the magnetic exchange coupling behavior substituting Cr(III) with Mo(III) in cyano-bridged transition metal complexes

NASA Astrophysics Data System (ADS)

Zhang, Yi-Quan; Luo, Cheng-Lin

Molecular magnetism in a series of cyano-bridged first and second transition metal complexes has been investigated using density functional theory (DFT) combined with the broken-symmetry (BS) approach. Several exchange-correlation (XC) functionals in the ADF package were used to investigate complexes I [-(Me3tacn)2(cyclam)NiMo2(CN)6]2+, II [-(Me3tacn)2(cyclam)Ni-Cr2(CN)6]2+, III [(Me3tacn)6MnMo6(CN)18]2+, and IV [(Me3tacn)6MnCr6(CN)18]2+ (Me3tacn = N,N?,N‴-trimethyl-1,4,7-triazacyclononane). For models A (the molded structure of complex I) and B (the modeled structure of complex II), all the XCs given qualitatively reasonable results and predict ferromagnetic coupling character between M (M = MoIII for A or CrIII for B) and NiII in coincidence with the experimental results (see Tables and ). The calculated using Operdew, OPBE, O3LYP, and B3LYP functionals and experimental J values show that substituting CrIII with MoIII will enhance the ferromagnetic exchange coupling interactions. But VWN, PW91, PBE, VSXC, and tau-HCTH functionals have no way to differentiate the relative strength of the intramolecular magnetic exchange coupling interactions of A and B correctly. For models C (the modeled structure of complex III) and D (the modeled structure of complex IV), all the XCs in ADF and B3LYP in Gaussian 03 with several basis sets show that substituting CrIII with MoIII will enhance the antiferromagnetic exchange coupling interactions. From the above calculations, the substitution of CrIII by MoIII will enhance the magnetic coupling interactions, whether the magnetic coupling interactions are ferro- or antiferromagnetic. Moreover, Kahn's model was applied to investigate the above facts.

6. VIEW OF GDOT BRIDGE NO. 02700268X00678N BRIDGE PLATE IDENTIFYING ...

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

6. VIEW OF GDOT BRIDGE NO. 027-00268X-00678N BRIDGE PLATE IDENTIFYING COUNTY COMMISSIONERS AT THE TIME OF CONSTRUCTION. - GDOT Bridge No. 027-00268X-00678N, County Road 268-Empress Road span Piscola Creek, Quitman, Brooks County, GA

SSI-bridge : soil bridge interaction during long-duration earthquake motions.

DOT National Transportation Integrated Search

2014-09-01

The seismic response of a complete soil-bridge system during shallow, crustal and subduction zone earthquakes is the topic of this report. Specifically, the effects of earthquake duration on the seismic performance of soil-bridge systems are examined...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

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

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-06

... DEPARTMENT OF TRANSPORTATION Federal Highway Administration Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice... for Users (SAFETEA-LU) (Pub. L. 109-59; 119 Stat. 1144) continued the highway bridge program to enable...

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

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-31

... DEPARTMENT OF TRANSPORTATION Federal Highway Administration Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice... for Users (SAFETEA-LU) (Pub. L. 109-59; 119 Stat. 1144) continued the highway bridge program to enable...

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

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-07

... DEPARTMENT OF TRANSPORTATION Federal Highway Administration Annual Materials Report on New Bridge Construction and Bridge Rehabilitation AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice... for Users (SAFETEA-LU) (Pub. L. 109-59; 119 Stat. 1144) continued the highway bridge program to enable...

Exchange coupling and magnetic anisotropy in a family of bipyrimidyl radical-bridged dilanthanide complexes: density functional theory and ab initio calculations.

PubMed

Zhang, Yi-Quan; Luo, Cheng-Lin; Zhang, Qiang

2014-05-05

The origin of the magnetic anisotropy energy barriers in a series of bpym(-) (bpym = 2,2'-bipyrimidine) radical-bridged dilanthanide complexes [(Cp*2Ln)2(μ-bpym)](+) [Cp* = pentamethylcyclopentadienyl; Ln = Gd(III) (1), Tb(III) (2), Dy(III) (3), Ho(III) (4), Er(III) (5)] has been explored using density functional theory (DFT) and ab initio methods. DFT calculations show that the exchange coupling between the two lanthanide ions for each complex is very weak, but the antiferromagnetic Ln-bpym(-) couplings are strong. Ab initio calculations show that the effective energy barrier of 2 or 3 mainly comes from the contribution of a single Tb(III) or Dy(III) fragment, which is only about one third of a single Ln energy barrier. For 4 or 5, however, both of the two Ho(III) or Er(III) fragments contribute to the total energy barrier. Thus, it is insufficient to only increase the magnetic anisotropy energy barrier of a single Ln ion, while enhancing the Ln-bpym(-) couplings is also very important. Copyright © 2014 Wiley Periodicals, Inc.

Biodiesel fuel production from waste cooking oil by the inclusion complex of heteropoly acid with bridged bis-cyclodextrin.

PubMed

Zou, Changjun; Zhao, Pinwen; Shi, Lihong; Huang, Shaobing; Luo, Pingya

2013-10-01

The inclusion complex of Cs2.5H0.5PW12O40 with bridged bis-cyclodextrin (CsPW/B) is prepared as a highly efficient catalyst for the direct production of biodiesel via the transesterification of waste cooking oil. CsPW/B is characterized by X-ray diffraction, and the biodiesel is analyzed by Gas Chromatography-Mass Spectrometer. The conversion rate of waste cooking oil is up to 94.2% under the optimum experimental conditions that are methanol/oil molar ratio of 9:1, catalyst dosage of 3 wt%, temperature of 65 °C and reaction time of 180 min. The physical properties of biodiesel sample satisfy the requirement of ASTM D6751 standards. The novel CsPW/B catalyst used for the transesterification can lead to 96.9% fatty acid methyl esters and 86.5% of the biodiesel product can serve as the ideal substitute for diesel fuel, indicating its excellent potential application in biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Damage assessment of bridge infrastructure subjected to flood-related hazards

NASA Astrophysics Data System (ADS)

Michalis, Panagiotis; Cahill, Paul; Bekić, Damir; Kerin, Igor; Pakrashi, Vikram; Lapthorne, John; Morais, João Gonçalo Martins Paulo; McKeogh, Eamon

2017-04-01

Transportation assets represent a critical component of society's infrastructure systems. Flood-related hazards are considered one of the main climate change impacts on highway and railway infrastructure, threatening the security and functionality of transportation systems. Of such hazards, flood-induced scour is a primarily cause of bridge collapses worldwide and one of the most complex and challenging water flow and erosion phenomena, leading to structural instability and ultimately catastrophic failures. Evaluation of scour risk under severe flood events is a particularly challenging issue considering that depth of foundations is very difficult to evaluate in water environment. The continual inspection, assessment and maintenance of bridges and other hydraulic structures under extreme flood events requires a multidisciplinary approach, including knowledge and expertise of hydraulics, hydrology, structural engineering, geotechnics and infrastructure management. The large number of bridges under a single management unit also highlights the need for efficient management, information sharing and self-informing systems to provide reliable, cost-effective flood and scour risk management. The "Intelligent Bridge Assessment Maintenance and Management System" (BRIDGE SMS) is an EU/FP7 funded project which aims to couple state-of-the art scientific expertise in multidisciplinary engineering sectors with industrial knowledge in infrastructure management. This involves the application of integrated low-cost structural health monitoring systems to provide real-time information towards the development of an intelligent decision support tool and a web-based platform to assess and efficiently manage bridge assets. This study documents the technological experience and presents results obtained from the application of sensing systems focusing on the damage assessment of water-hazards at bridges over watercourses in Ireland. The applied instrumentation is interfaced with an open

Comprehensive evaluation of fracture critical bridges.

DOT National Transportation Integrated Search

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, ...

Evaluation of bridge replacement alternatives for the county bridge system.

DOT National Transportation Integrated Search

1994-08-01

Recent reports have indicated that 23.5 percent of the nation's highway bridges are : structurally deficient and 17.7 percent are functionally obsolete. A significant number of these bridges : are on the Iowa county road system. The objective of the ...

Summary and Comparison of Multiphase Streambed Scour Analysis at Selected Bridge Sites in Alaska

USGS Publications Warehouse

Conaway, Jeffrey S.

2004-01-01

The U.S. Geological Survey and the Alaska Department of Transportation and Public Facilities undertook a cooperative multiphase study of streambed scour at selected bridges in Alaska beginning in 1994. Of the 325 bridges analyzed for susceptibility to scour in the preliminary phase, 54 bridges were selected for a more intensive analysis that included site investigations. Cross-section geometry and hydraulic properties for each site in this study were determined from field surveys and bridge plans. Water-surface profiles were calculated for the 100- and 500-year floods using the Hydrologic Engineering Center?s River Analysis System and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths for the 100- and 500-year recurrence-interval discharges exceeded 5 feet at six bridges, and pier-scour depths exceeded 10 feet at 24 bridges. Complex pier-scour computations were made at 10 locations where the computed contraction-scour depths would expose pier footings. Pressure scour was evaluated at three bridges where the modeled flood water-surface elevations intersected the bridge structure. Site investigation at the 54 scour-critical bridges was used to evaluate the effectiveness of the preliminary scour analysis. Values for channel-flow angle of attack and approach-channel width were estimated from bridge survey plans for the preliminary study and were measured during a site investigation for this study. These two variables account for changes in scour depths between the preliminary analysis and subsequent reanalysis for most sites. Site investigation is needed for best estimates of scour at bridges with survey plans that indicate a channel-flow angle of attack and for locations where survey plans did not include sufficient channel geometry upstream of the bridge.

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

Treesearch

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

Treesearch

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...

Performance evaluation of bridges with structural bridge deck overlays (SBDO).

DOT National Transportation Integrated Search

2006-03-01

Structural Bridge Deck Overlay (SBDO) involves applying 6 to 10 inches (150 to 200 mm) of normal weight, class AA, reinforced concrete directly to a bridges original slab. The overlay is designed to increase the deck elevation to an extent that st...

Long continuous bridge deck evaluation : John Day River Bridge, Clatsop County, Bridge No. 1827B : final report.

DOT National Transportation Integrated Search

1995-06-01

The John Day River Bridge, near Astoria, Oregon was built with a continuous deck length of 1,105 ft. (340 m). The rationale for designing the John Day River Bridge with an unusually long continuous deck is in part based on the site's very mild climat...

Reconfigurable wireless monitoring systems for bridges: validation on the Yeondae Bridge

NASA Astrophysics Data System (ADS)

Kim, Junhee; Lynch, Jerome P.; Zonta, Daniele; Lee, Jong-Jae; Yun, Chung-Bang

2009-03-01

The installation of a structural monitoring system on a medium- to large-span bridge can be a challenging undertaking due to high system costs and time consuming installations. However, these historical challenges can be eliminated by using wireless sensors as the primary building block of a structural monitoring system. Wireless sensors are low-cost data acquisition nodes that utilize wireless communication to transfer data from the sensor to the data repository. Another advantageous characteristic of wireless sensors is their ability to be easily removed and reinstalled in another sensor location on the same structure; this installation modularity is highlighted in this study. Wireless sensor nodes designed for structural monitoring applications are installed on the 180 m long Yeondae Bridge (Korea) to measure the dynamic response of the bridge to controlled truck loading. To attain a high nodal density with a small number (20) of wireless sensors, the wireless sensor network is installed three times with each installation concentrating sensors in one portion of the bridge. Using forced and free vibration response data from the three installations, the modal properties of the bridge are accurately identified. Intentional nodal overlapping of the three different sensor installations allows mode shapes from each installation to be stitched together into global mode shapes. Specifically, modal properties of the Yeondae Bridge are derived off-line using frequency domain decomposition (FDD) modal analysis methods.

33 CFR 115.40 - Bridge repairs.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which do...

33 CFR 115.40 - Bridge repairs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which do...

Building Better Bridges into STEM: A Synthesis of 25 Years of Literature on STEM Summer Bridge Programs

PubMed Central

Ashley, Michael; Cooper, Katelyn M.; Cala, Jacqueline M.; Brownell, Sara E.

2017-01-01

Summer bridge programs are designed to help transition students into the college learning environment. Increasingly, bridge programs are being developed in science, technology, engineering, and mathematics (STEM) disciplines because of the rigorous content and lower student persistence in college STEM compared with other disciplines. However, to our knowledge, a comprehensive review of STEM summer bridge programs does not exist. To provide a resource for bridge program developers, we conducted a systematic review of the literature on STEM summer bridge programs. We identified 46 published reports on 30 unique STEM bridge programs that have been published over the past 25 years. In this review, we report the goals of each bridge program and whether the program was successful in meeting these goals. We identify 14 distinct bridge program goals that can be organized into three categories: academic success goals, psychosocial goals, and department-level goals. Building on the findings of published bridge reports, we present a set of recommendations for STEM bridge programs in hopes of developing better bridges into college. PMID:29146667

Evaluation of streambed scour at bridges over tidal waterways in Alaska

USGS Publications Warehouse

Conaway, Jeffrey S.; Schauer, Paul V.

2012-01-01

Engineering Center’s River Analysis System model, and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths were greater than 2.0 feet at five bridges and computed pier-scour depths were 4.0 feet or greater at 15 bridges. The potential for streambed scour by both coastal and riverine processes at the bridges considered in this study were evaluated, ranked, and summed to determine a cumulative risk factor for each bridge. Possible factors that could mitigate the scour risks were investigated at 22 bridges that had high individual or cumulative rankings. Mitigating factors such as piers founded in bedrock, deep pier foundations relative to scour depths, and lack of observed scour during field measurements were documented for 13 sites, but additional study and monitoring is needed to better quantify the streambed scour potential for nine sites. Three bridges prone to being affected by storm surges will require more data collection and possibly complex hydrodynamic modeling to accurately quantify the streambed scour potential. Continuous monitoring of water-surface and streambed elevation at one or more piers is needed for two bridges to better understand the tidal and riverine influences on streambed scour.

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

PubMed

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.

How well do force fields capture the strength of salt bridges in proteins?

PubMed Central

Ahmed, Mustapha Carab; Papaleo, Elena

2018-01-01

Salt bridges form between pairs of ionisable residues in close proximity and are important interactions in proteins. While salt bridges are known to be important both for protein stability, recognition and regulation, we still do not have fully accurate predictive models to assess the energetic contributions of salt bridges. Molecular dynamics simulation is one technique that may be used study the complex relationship between structure, solvation and energetics of salt bridges, but the accuracy of such simulations depends on the force field used. We have used NMR data on the B1 domain of protein G (GB1) to benchmark molecular dynamics simulations. Using enhanced sampling simulations, we calculated the free energy of forming a salt bridge for three possible lysine-carboxylate ionic interactions in GB1. The NMR experiments showed that these interactions are either not formed, or only very weakly formed, in solution. In contrast, we show that the stability of the salt bridges is overestimated, to different extents, in simulations of GB1 using seven out of eight commonly used combinations of fixed charge force fields and water models. We also find that the Amber ff15ipq force field gives rise to weaker salt bridges in good agreement with the NMR experiments. We conclude that many force fields appear to overstabilize these ionic interactions, and that further work may be needed to refine our ability to model quantitatively the stability of salt bridges through simulations. We also suggest that comparisons between NMR experiments and simulations will play a crucial role in furthering our understanding of this important interaction.

Aeroelastic Response from Indicial Functions with a Finite Element Model of a Suspension Bridge

NASA Astrophysics Data System (ADS)

Mikkelsen, O.; Jakobsen, J. B.

2017-12-01

The present paper describes a comprehensive analysis of the aeroelastic bridge response in time-domain, with a finite element model of the structure. The main focus is on the analysis of flutter instability, accounting for the wind forces generated by the bridge motion, including twisting as well as vertical and horizontal translation, i.e. all three global degrees of freedom. The solution is obtained by direct integration of the equations of motion for the bridge-wind system, with motion-dependent forces approximated from flutter derivatives in terms of rational functions. For the streamlined bridge box-girder investigated, the motion dependent wind forces related to the along-wind response are found to have a limited influence on the flutter velocity. The flutter mode shapes in the time-domain and the frequency domain are consistent, and composed of the three lowest symmetrical vertical modes coupled with the first torsional symmetric mode. The method applied in this study provides detailed response estimates and contributes to an increased understanding of the complex aeroelastic behaviour of long-span bridges.

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

NASA Astrophysics Data System (ADS)

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

2001-10-01

This paper presents the results of research work on modal identification of Tsing Ma bridge ambient testing data by using an improved eigensystem realization algorithm. The testing was carried out before the bridge was open to traffic and after the completion of surfacing. Without traffic load, ambient excitations were much less intensive, and the bridge responses to such ambient excitation were also less intensive. Consequently, the bridge responses were significantly influenced by the random movement of heavy construction vehicles on the deck. To cut off noises in the testing data and make the ambient signals more stationary, the Chebyshev digital filter was used instead of the digital filter with a Hanning window. Random decrement (RD) functions were built to convert the ambient responses to free vibrations. An improved eigensystem realization algorithm was employed to improve the accuracy and the efficiency of modal identification. It uses cross-correlation functions ofRD functions to form the Hankel matrix instead of RD functions themselves and uses eigenvalue decomposition instead of singular value decomposition. The data for response accelerations were acquired group by group because of limited number of high-quality accelerometers and channels of data loggers available. The modes were identified group by group and then assembled by using response accelerations acquired at reference points to form modes of the complete bridge. Seventy-nine modes of the Tsing Ma bridge were identified, including five complex modes formed in accordance with unevenly distributed damping in the bridge. The identified modes in time domain were then compared with those identified in frequency domain and finite element analytical results.

83. DETAIL OF THE MUZZLE END OF THE LAUNCHER BRIDGE ...

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

83. DETAIL OF THE MUZZLE END OF THE LAUNCHER BRIDGE ON TEMPORARY SUPPORTS LOOKING NORTHEAST SHOWING TWO LAUNCHING TUBES, Date unknown, circa 1950'S. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

9. DETAIL VIEW OF BRIDGE CRANE ON WEST SIDE OF ...

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

9. DETAIL VIEW OF BRIDGE CRANE ON WEST SIDE OF BUILDING. CAMERA FACING NORTHEAST. CONTAMINATED AIR FILTERS LOADED IN TRANSPORT CASKS WERE TRANSFERRED TO VEHICLES AND SENT TO RADIOACTIVE WASTE MANAGEMENT COMPLEX FOR STORAGE. INEEL PROOF NUMBER HD-17-1. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Advanced bridge safety initiative : FRP flexural retrofit for concrete slab bridges - task 4 deliverables.

DOT National Transportation Integrated Search

2014-06-01

Concrete slab bridges are being examined as part of the MaineDOT Advanced Bridge Safety Initiative. Under Tasks : 1 3 a finite element analysis program is developed, validated and applied to twenty bridges. : Task 4 investigates and develops a no...

Semiconductor bridge (SCB) detonator

DOEpatents

Bickes, Jr., Robert W.; Grubelich, Mark C.

1999-01-01

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

Semiconductor bridge (SCB) detonator

DOEpatents

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

1999-01-19

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

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

NASA Astrophysics Data System (ADS)

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.

Scaling law on formation and rupture of a dynamical liquid bridge

NASA Astrophysics Data System (ADS)

Zhang, Huang; Zhang, Zehao; Liu, Qianfeng; Li, Shuiqing; Department of Thermal Engineering, Tsinghua University Collaboration; Institute of Nuclear Energy; Technology, Tsinghua University Collaboration

2017-11-01

The formation and breakup of a pendular liquid bridge in dynamic state is investigated experimentally. The experimental setup arises from a system to measure the coefficient of restitution (COR) of a glass sphere impacting and bouncing on a wetted surface. We compare the effect of surface tension and gravity on the liquid bridge rupture by the capillary length κ-1. For water and liquid 1 (50% water mixed with 50% glycerol), the gravity is dominant on the liquid bridge breakup. And we find that the rupture distance is in good linear trend with the non-dimensional number G by the scaling law analysis. Further, for liquid 2 (25% water mixed with 75% glycerol) that is relatively high viscous, the linear changing of the rupture distance with the capillary number Ca is found. The relation of the rupture distance with G and Ca would be helpful in understanding the complex behavior of the dynamical liquid bridge. This work was funded by the Major State Basic Research Development Program of China (Grant No. 2016YFC0203705) and the China Postdoctoral Science Foundation (Grant No. 2016M601024).

Seafloor off Natural Bridges State Beach, Santa Cruz, California

USGS Publications Warehouse

Storlazzi, Curt D.; Golden, Nadine E.; Gibbons, Helen

2013-01-01

The seafloor off Natural Bridges State Beach, Santa Cruz, California, is extremely varied, with sandy flats, boulder fields, faults, and complex bedrock ridges. These ridges support rich marine ecosystems; some of them form the "reefs" that produce world-class surf breaks. Colors indicate seafloor depth, from red-orange (about 2 meters or 7 feet) to magenta (25 meters or 82 feet).

Bridge Workshop : Enhancing Bridge Performance, February 21-22, 2008, Reston, Virginia : workshop report

Treesearch

Sreenivas Alampalli; Sheila Rimal Duwadi; Reagan Sentelle Herman; Danielle D. Kleinhans; Khaled Mahmoud; James C. Ray; James P. Wacker; Nur Yazdani

2008-01-01

The participants to the workshop were given the charge to discuss (1) bridge design issues including best practices in design and detailing that could be used to improve durability, extend service life and prevent premature deterioration, (2) performance measures needed to better determine bridge condition, (3) technologies that could be used to monitor bridge life and...

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

Treesearch

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...

Seismic testing of precast segmental bridges, Phase III : bridge system test.

DOT National Transportation Integrated Search

2005-06-01

This report discusses the main findings of a test examining the seismic behavior of a precast, post-tensioned, segmental bridge : superstructure with a cast-in-place, hollow, rectangular column. The half-scale specimen modeled a prototype bridge from...

Bridge deck deicing

DOT National Transportation Integrated Search

1998-01-01

Concrete bridge decks are prone to ice accumulation. The use of road salts and chemicals for deicing is cost effective but causes damage to concrete and corrosion of reinforcing steel in concrete bridge decks. This problem is a major concern to trans...

Removal of failed crown and bridge

PubMed Central

Rahul, G R.; Poduval, Soorya T.; Shetty, Karunakar

2012-01-01

Crown and bridge have life span of many years but they fail for a number of reasons. Over the years, many devices have been designed to remove crowns and bridges from abutment teeth. While the removal of temporary crowns and bridges is usually very straightforward, the removal of a definitive cast crown with unknown cement is more challenging. Removal is often by destructive means. There are a number of circumstances, however, in which conservative disassembly would aid the practitioner in completing restorative/endodontic procedures. There are different mechanisms available to remove a failed crown or bridge. But there is no information published about the classification of available systems for crown and bridge removal. So it is logical to classify these systems into different groups which can help a clinician in choosing a particular type of system depending upon the clinical situation. The aim of this article is to provide a classification for various crown and bridge removal systems; describe how a number of systems work; and when and why they might be used. A PubMed search of English literature was conducted up to January 2010 using the terms: Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. Additionally, the bibliographies of 3 previous reviews, their cross references as well as articles published in various journals like International Endodontic Journal, Journal of Endodontics and were manually searched. Key words:Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. PMID:24558549

49 CFR 237.109 - Bridge inspection records.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Bridge inspection records. 237.109 Section 237.109..., DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.109 Bridge inspection records... performed on those bridges under this part. (b) Each record of an inspection under the bridge management...

49 CFR 237.109 - Bridge inspection records.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Bridge inspection records. 237.109 Section 237.109..., DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.109 Bridge inspection records... performed on those bridges under this part. (b) Each record of an inspection under the bridge management...

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

Treesearch

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

PubMed Central

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

2014-01-01

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

Salt-bridge energetics in halophilic proteins.

PubMed

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

Long-term monitoring of a cable stayed bridge using a SCADA system

NASA Astrophysics Data System (ADS)

Torbol, Marco; Kim, Sehwan; Shinozuka, Masanobu

2012-04-01

DuraMote is a MEMS-based remote sensing system, which is developed for the NIST TIP project, Next Generation SCADA for Prevention and Mitigation of Water System Infrastructure Disaster. It is designed for supervisory control and data acquisition (SCADA) of pipe ruptures in water distribution systems. In this project, a method is developed to detect the pipe ruptures by analyzing the acceleration data gathered by DuraMote which consists of two primary components; the first, "Gopher" contains the accelerometers and are attached to the water pipe surface noninvasively, and the second, "Roocas" is placed above ground supplying the power to, and retrieving the data from the multiple Gophers, and then transmit the data through Wi-Fi to a base station. The relays support the Wi-Fi network to facilitate the transmission. A large scale bridge provides an ideal test-bet to validate the performance of such a complex monitoring system as DuraMote for its accuracy, reliability, robustness, and user friendliness. This is because a large bridge is most of the time subjected to susceptible level of ambient vibration due to passing loads, wind, etc. DuraMote can record the acceleration time history arising from the vibration making it possible to estimate the frequency values of various bridge vibration modes. These estimated frequency values are then compared with the values computed from analytical model of the bridge for the verification of the accuracy of DuraMote. It is noted that such a verification method cannot be used practically by deploying DuraMote on a water distribution network since the dynamic behavior of a pipe network, either above or underground, is too complex to model analytically for this purpose, and in addition, the network generally lacks conveniently recordable ambient vibration. In this experiment, the performance of DuraMote system was tested being installed on the Hwamyung Bridge, a 500 m long RC cable stayed bridge in Korea for long term monitoring. In

Phenoxo bridged dinuclear Zn(II) Schiff base complex as new precursor for preparation zinc oxide nanoparticles: Synthesis, characterization, crystal structures and photoluminescence studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saeednia, S., E-mail: sami_saeednia@yahoo.com; Iranmanesh, P.; Ardakani, M. Hatefi

Highlights: • A novel nano-scale Zn(II) complex was synthesized by solvothermal method. • Chemical structure of the nanostructures was characterized as well as bulk complex. • The photoluminescence property of the complex was investigated at room temperature. • The thermogravimetry and differential thermal analysis were carried out. • Thermal decomposition of the nanostructures was prepared zinc oxide nanoparticles. - Abstract: Nanoparticles of a novel Zn(II) Schiff base complex, [Zn(HL)NO{sub 3}]{sub 2} (1), (H{sub 2}L = 2-[(2-hydroxy-propylimino) methyl] phenol), was synthesized by using solvothermal method. Shape, morphology and chemical structure of the synthesized nanoparticles were characterized by scanning electron microscopy (SEM),more » X-ray powder diffraction (XRD), Fourier Transform Infrared Spectoscopy (FT-IR) and UV–vis spectroscopy. Structural determination of compound 1 was determined by single-crystal X-ray diffraction. The results were revealed that the zinc complex is a centrosymmetric dimer in which deprotonated phenolates bridge the two five-coordinate metal atoms and link the two halves of the dimer. The thermal stability of compound 1 was analyzed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of the initial substrates concentration and reaction time on size and morphology of compound 1 nanostructure was investigated as well. Furthermore, the luminescent properties of the complex 1 were examined. ZnO nanoparticles with diameter between 15 and 20 nm were simply synthesized by solid-state transformation of compound 1 at 700 °C.« less

Electronically Strongly Coupled Divinylheterocyclic-Bridged Diruthenium Complexes.

PubMed

Pfaff, Ulrike; Hildebrandt, Alexander; Korb, Marcus; Oßwald, Steffen; Linseis, Michael; Schreiter, Katja; Spange, Stefan; Winter, Rainer F; Lang, Heinrich

2016-01-11

Complexes [{Ru(CO)Cl(PiPr3 )2 }2 (μ-2,5-(CH-CH)2 -(c) C4 H2 E] (E=NR; R=C6 H4 -4-NMe2 (10 a), C6 H4 -4-OMe (10 b), C6 H4 -4-Me (10 c), C6 H5 (10 d), C6 H4 -4-CO2 Et (10 e), C6 H4 -4-NO2 (10 f), C6 H3 -3,5-(CF3 )2 (10 g), CH3 (11); E=O (12), S (13)) are discussed. The solid state structures of four alkynes and two complexes are reported. (Spectro)electrochemical studies show a moderate influence of the nature of the heteroatom and the electron-donating or -withdrawing substituents R in 10 a-g on the electrochemical and spectroscopic properties. The CVs display two consecutive one-electron redox events with ΔE°'=350-495 mV. A linear relationship between ΔE°' and the σp Hammett constant for 10 a-f was found. IR, UV/Vis/NIR and EPR studies for 10(+) -13(+) confirm full charge delocalization over the {Ru}CH-CH-heterocycle-CH-CH{Ru} backbone, classifying them as Class III systems according to the Robin and Day classification. DFT-optimized structures of the neutral complexes agree well with the experimental ones and provide insight into the structural consequences of stepwise oxidations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

57. INTERIOR VIEW OF VAL BRIDGE STRUCTURE SHOWING LAUNCHING TUBE, ...

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

57. INTERIOR VIEW OF VAL BRIDGE STRUCTURE SHOWING LAUNCHING TUBE, STAIRS AND PORTION OF LAUNCHING DECK. NOTE SUPPORT CARRIAGE ASSEMBLY IN DISTANCE. Date unknown, circa March 1948. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

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

Treesearch

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....

Field performance of timber bridges. 14, Dean, Hibbsville, and Decatur stress-laminated deck bridges

Treesearch

P. D. Hilbrich Lee; M. A. Ritter; S. Golston; K. Hinds

1984-01-01

The Dean, Hibbsville, and Decatur bridges were constructed in southern Iowa during 1994. Each bridge is a simple-span, stress-laminated deck superstructure, approximately 7.3 m (24 ft) long, constructed from eastern cottonwood lumber. The performance of each bridge was monitored for approximately 2 years, beginning shortly after installation. Monitoring involved...

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

DOT National Transportation Integrated Search

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 ...

Assessment of bridge abutment scour and sediment transport under various flow conditions

NASA Astrophysics Data System (ADS)

Gilja, Gordon; Valyrakis, Manousos; Michalis, Panagiotis; Bekić, Damir; Kuspilić, Neven; McKeogh, Eamon

2017-04-01

Safety of bridges over watercourses can be compromised by flow characteristics and bridge hydraulics. Scour process around bridge foundations can develop rapidly during low-recurrence interval floods when structural elements are exposed to increased flows. Variations in riverbed geometry, as a result of sediment removal and deposition processes, can increase flood-induced hazard at bridge sites with catastrophic failures and destructive consequences for civil infrastructure. The quantification of flood induced hazard on bridge safety generally involves coupled hydrodynamic and sediment transport models (i.e. 2D numerical or physical models) for a range of hydrological events covering both high and low flows. Modelled boundary conditions are usually estimated for their probability of occurrence using frequency analysis of long-term recordings at gauging stations. At smaller rivers gauging station records are scarce, especially in upper courses of rivers where weirs, drops and rapids are common elements of river bathymetry. As a result, boundary conditions that accurately represent flow patterns on modelled river reach cannot be often reliably acquired. Sediment transport process is also more complicated to describe due to its complexity and dependence to local flow field making scour hazard assessment a particularly challenging issue. This study investigates the influence of flow characteristics to the development of scour and sedimentation processes around bridge abutments of a single span masonry arch bridge in south Ireland. The impact of downstream weirs on bridge hydraulics through variation of downstream model domain type is also considered in this study. The numerical model is established based on detailed bathymetry data surveyed along a rectangular grid of 50cm spacing. Acquired data also consist of riverbed morphology and water level variations which are monitored continuously on bridge site. The obtained data are then used to compare and calibrate

Two test level 4 bridge railing and transition systems for transverse timber deck bridges

Treesearch

Ronald K. Faller; Michael A. Ritter; Barry T. Rosson; Michael D. Fowler; Sheila R. Duwadi

2000-01-01

The Midwest Roadside Safety Facility, in cooperation with the Forest Products Laboratory, which is part of the U.S. Department of Agricultureas Forest Service, and FHWA, designed two bridge railing and approach guardrail transition systems for use on bridges with transverse glue-laminated timber decks. The bridge raging and transition systems were developed and crash...

Geotextile reinforced bridge approach embankment : Lake River Bridge : Malin Highway , Klamath County, Oregon : construction report.

DOT National Transportation Integrated Search

1993-03-01

The transition from the roadway to the deck of a rigidly supported bridge is of concern to engineers and the travelling public. It is a common occurrence to feel a discontinuity between the roadway and bridge structure. Bridge engineers have tried to...

49 CFR 237.103 - Bridge inspection procedures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Bridge inspection procedures. 237.103 Section 237... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.103 Bridge inspection procedures. (a) Each bridge management program shall specify the procedure to be used for...

Temperature differential of swingspan bridges : final report.

DOT National Transportation Integrated Search

1969-06-01

This report describes a study performed to determine the temperature differential of the top and bottom member of one side of a swingspan bridge. Three bridges were used in the study. Bridge No. 1 was an equal-arm swingspan bridge, Bridge No. 2 was a...

49 CFR 237.103 - Bridge inspection procedures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Bridge inspection procedures. 237.103 Section 237... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.103 Bridge inspection procedures. (a) Each bridge management program shall specify the procedure to be used for...

Building Better Bridges into STEM: A Synthesis of 25 Years of Literature on STEM Summer Bridge Programs.

PubMed

Ashley, Michael; Cooper, Katelyn M; Cala, Jacqueline M; Brownell, Sara E

2017-01-01

Summer bridge programs are designed to help transition students into the college learning environment. Increasingly, bridge programs are being developed in science, technology, engineering, and mathematics (STEM) disciplines because of the rigorous content and lower student persistence in college STEM compared with other disciplines. However, to our knowledge, a comprehensive review of STEM summer bridge programs does not exist. To provide a resource for bridge program developers, we conducted a systematic review of the literature on STEM summer bridge programs. We identified 46 published reports on 30 unique STEM bridge programs that have been published over the past 25 years. In this review, we report the goals of each bridge program and whether the program was successful in meeting these goals. We identify 14 distinct bridge program goals that can be organized into three categories: academic success goals, psychosocial goals, and department-level goals. Building on the findings of published bridge reports, we present a set of recommendations for STEM bridge programs in hopes of developing better bridges into college. © 2017 M. Ashley, K. M. Cooper, et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Slow magnetic relaxation in carbonato-bridged dinuclear lanthanide(III) complexes with 2,3-quinoxalinediolate ligands.

PubMed

Vallejo, Julia; Cano, Joan; Castro, Isabel; Julve, Miguel; Lloret, Francesc; Fabelo, Oscar; Cañadillas-Delgado, Laura; Pardo, Emilio

2012-08-11

The coordination chemistry of the 2,3-quinoxalinediolate ligand with different lanthanide(III) ions in basic media in air affords a new family of carbonato-bridged M(2)(III) compounds (M = Pr, Gd and Dy), the Dy(2)(III) analogue exhibiting slow magnetic relaxation behaviour typical of single-molecule magnets.

23 CFR 650.307 - Bridge inspection organization.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Bridge inspection organization. 650.307 Section 650.307... BRIDGES, STRUCTURES, AND HYDRAULICS National Bridge Inspection Standards § 650.307 Bridge inspection... bridges located on public roads that are fully or partially located within the State's boundaries, except...

23 CFR 650.809 - Movable span bridges.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 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...

23 CFR 650.809 - Movable span bridges.

Code of Federal Regulations, 2010 CFR

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...

Note: Rapid offset reduction of impedance bridges taking into account instrumental damping and phase shifting.

PubMed

van der Wel, C M; Kortschot, R J; Bakelaar, I A; Erné, B H; Kuipers, B W M

2013-03-01

The sensitivity of an imperfectly balanced impedance bridge is limited by the remaining offset voltage. Here, we present a procedure for offset reduction in impedance measurements using a lock-in amplifier, by applying a complex compensating voltage external to the bridge. This procedure takes into account instrumental damping and phase shifting, which generally occur at the high end of the operational frequency range. Measurements demonstrate that the output of the circuit rapidly converges to the instrumentally limited noise at any frequency.

Coupling vibration research on Vehicle-bridge system

NASA Astrophysics Data System (ADS)

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.

Glycosylinositol phosphorylceramides from Rosa cell cultures are boron-bridged in the plasma membrane and form complexes with rhamnogalacturonan II

PubMed Central

Voxeur, Aline; Fry, Stephen C

2014-01-01

Boron (B) is essential for plant cell-wall structure and membrane functions. Compared with its role in cross-linking the pectic domain rhamnogalacturonan II (RG-II), little information is known about the biological role of B in membranes. Here, we investigated the involvement of glycosylinositol phosphorylceramides (GIPCs), major components of lipid rafts, in the membrane requirement for B. Using thin-layer chromatography and mass spectrometry, we first characterized GIPCs from Rosa cell culture. The major GIPC has one hexose residue, one hexuronic acid residue, inositol phosphate, and a ceramide moiety with a C18 trihydroxylated mono-unsaturated long-chain base and a C24 monohydroxylated saturated fatty acid. Disrupting B bridging (by B starvation in vivo or by treatment with cold dilute HCl or with excess borate in vitro) enhanced the GIPCs’ extractability. As RG-II is the main B-binding site in plants, we investigated whether it could form a B-centred complex with GIPCs. Using high-voltage paper electrophoresis, we showed that addition of GIPCs decreased the electrophoretic mobility of radiolabelled RG-II, suggesting formation of a GIPC–B–RG-II complex. Last, using polyacrylamide gel electrophoresis, we showed that added GIPCs facilitate RG-II dimerization in vitro. We conclude that B plays a structural role in the plasma membrane. The disruption of membrane components by high borate may account for the phytotoxicity of excess B. Moreover, the in-vitro formation of a GIPC–B–RG-II complex gives the first molecular explanation of the wall–membrane attachment sites observed in vivo. Finally, our results suggest a role for GIPCs in the RG-II dimerization process. PMID:24804932

Insight into Oxide-Bridged Heterobimetallic Al/Zr Olefin Polymerization Catalysts.

PubMed

Boulho, Cédric; Zijlstra, Harmen S; Hofmann, Alexander; Budzelaar, Peter H M; Harder, Sjoerd

2016-11-21

Reaction of (TBBP)AlMe⋅THF with [Cp* 2 Zr(Me)OH] gave [(TBBP)Al(THF)-O-Zr(Me)Cp* 2 ] (TBBP=3,3',5,5'-tetra-tBu-2,2'-biphenolato). Reaction of [DIPPnacnacAl(Me)-O-Zr(Me)Cp 2 ] with [PhMe 2 NH] + [B(C 6 F 5 ) 4 ] - gave a cationic Al/Zr complex that could be structurally characterized as its THF adduct [(DIPPnacnac)Al(Me)-O-Zr(THF)Cp 2 ] + [B(C 6 F 5 ) 4 ] - (DIPPnacnac=HC[(Me)C=N(2,6-iPr 2 -C 6 H 3 )] 2 ). The first complex polymerizes ethene in the presence of an alkylaluminum scavenger but in the absence of methylalumoxane (MAO). The adduct cation is inactive under these conditions. Theoretical calculations show very high energy barriers (ΔG=40-47 kcal mol -1 ) for ethene insertion with a bridged AlOZr catalyst. This is due to an unfavorable six-membered-ring transition state, in which the methyl group bridges the metal and ethene with an obtuse metal-Me-C angle that prevents synchronized bond-breaking and making. A more-likely pathway is dissociation of the Al-O-Zr complex into an aluminate and the active polymerization catalyst [Cp* 2 ZrMe] + . © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wireless ultrasonic wavefield imaging via laser for hidden damage detection inside a steel box girder bridge

NASA Astrophysics Data System (ADS)

An, Yun-Kyu; Song, Homin; Sohn, Hoon

2014-09-01

This paper presents a wireless ultrasonic wavefield imaging (WUWI) technique for detecting hidden damage inside a steel box girder bridge. The proposed technique allows (1) complete wireless excitation of piezoelectric transducers and noncontact sensing of the corresponding responses using laser beams, (2) autonomous damage visualization without comparing against baseline data previously accumulated from the pristine condition of a target structure and (3) robust damage diagnosis even for real structures with complex structural geometries. First, a new WUWI hardware system was developed by integrating optoelectronic-based signal transmitting and receiving devices and a scanning laser Doppler vibrometer. Next, a damage visualization algorithm, self-referencing f-k filter (SRF), was introduced to isolate and visualize only crack-induced ultrasonic modes from measured ultrasonic wavefield images. Finally, the performance of the proposed technique was validated through hidden crack visualization at a decommissioned Ramp-G Bridge in South Korea. The experimental results reveal that the proposed technique instantaneously detects and successfully visualizes hidden cracks even in the complex structure of a real bridge.

Heterobimetallic thiocyanato-bridged coordination polymers based on [Hg(SCN) 4] 2-: Synthesis, crystal structure, magnetic properties and ESR studies

NASA Astrophysics Data System (ADS)

Jian, Fang-Fang; Xiao, Hai-Lian; Liu, Fa Qian

2006-12-01

Three new M/Hg bimetallic thiocyanato-bridged coordination polymers; [Hg(SCN) 4Ni(Im) 3] ∞1, [Hg(SCN) 4Mn(Im) 2] ∞2, and [Hg(SCN) 4Cu(Me-Im) 2 Hg(SCN) 4Cu(Me-Im) 4] ∞3, (Im=imidazole, Me-Im= N-methyl-imidazole), have been synthesized and characterized by means of elemental analysis, ESR, and single-crystal X-ray. X-ray diffraction analysis reveals that these three complexes all form 3D network structure, and their structures all contain a thiocyanato-bridged Hg⋯M⋯Hg chain ( M=Mn, Ni, Cu) in which the metal and mercury centers exhibit different coordination environments. In complex 1, the [Hg(SCN) 4] 2- anion connects three [Ni(Im) 3] 2+ using three SCN ligands giving rise to a 3D structure, and in complex 2, four SCN ligands bridge [Hg(SCN) 4] 2- and [Mn(Im) 2] 2+ to form a 3D structure. The structure of 3 contains two copper atoms with distinct coordination environment; one is coordinated by four N-methyl-imidazole ligands and two axially elongated SCN groups, and another by four SCN groups (two elongated) and two N-methyl-imidazole ligands. The magnetic property of complex 1 has been investigated. The spin state structure in hetermetallic NiHgNi systems of complex 1 is irregular. The ESR spectra results of complex 3 demonstrate Cu 2+ ion lie on octahedral environment.

Hydrographic surveys of the Missouri and Yellowstone Rivers at selected bridges and through Bismarck, North Dakota, during the 2011 flood

USGS Publications Warehouse

Densmore, Brenda K.; Strauch, Kellan R.; Dietsch, Benjamin J.

2013-01-01

The U.S. Geological Survey (USGS), in cooperation with the North Dakota Department of Transportation and the North Dakota State Water Commission, completed hydrographic surveys at six Missouri River bridges and one Yellowstone River bridge during the 2011 flood of the Missouri River system. Bridges surveyed are located near the cities of Cartwright, Buford, Williston, Washburn, and Bismarck, N. Dak. The river in the vicinity of the bridges and the channel through the city of Bismarck, N. Dak., were surveyed. The hydrographic surveys were conducted using a high-resolution multibeam echosounder (MBES), the RESON SeaBatTM 7125, during June 6–9 and June 28–July 9, 2011. The surveyed area at each bridge site extended 820 feet upstream from the bridge to 820 feet downstream from the bridge. The surveyed reach through Bismarck consisted of 18 miles of the main channel wherever depth was sufficient. Results from these emergency surveys aided the North Dakota Department of Transportation in evaluating the structural integrity of the bridges during high-flow conditions. In addition, the sustained high flows made feasible the surveying of a large section of the normally shallow channel with the MBES. In general, results from sequential bridge surveys showed that as discharge increased between the first and second surveys at a given site, there was a general trend of channel scour. Locally, complex responses of scour in some areas and deposition in other areas of the channel were identified. Similarly, scour around bridge piers also showed complex responses to the increase in flow between the two surveys. Results for the survey area of the river channel through Bismarck show that, in general, scour occurred around river structures or where the river has tight bends and channel narrowing. The data collected during the surveys are provided electronically in two different file formats: comma delimited text and CARIS Spatial ArchiveTM (CSARTM) format.

Active-bridge oscillator

DOEpatents

Wessendorf, Kurt O.

2001-01-01

An active bridge oscillator is formed from a differential amplifier where positive feedback is a function of the impedance of one of the gain elements and a relatively low value common emitter resistance. This use of the nonlinear transistor parameter h stabilizes the output and eliminates the need for ALC circuits common to other bridge oscillators.

Bridging a cultural gap

NASA Astrophysics Data System (ADS)

Leviatan, Talma

2008-09-01

There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes—aimed at bridging the gap between high-school mathematics and tertiary mathematics—is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a potential bridging programme, this paper aims at demonstrating that the gap can be bridged, by presenting an ongoing modular bridging programme especially designed for the diverse types of student populations in teachers training colleges. We also present here some innovative teaching and assessment methods that were judged essential for the success of these programmes—focusing mainly on the "Questionnaire Based Instruction Method". Finally we suggest directions of follow up and research.

Bridge inspector's manual for movable bridges.

DOT National Transportation Integrated Search

1977-01-01

Importance of Inspection-Movable bridges are built to the rigid specifications : of such groups as the American Association of State Highway and : Transportation Officials (AASHTO), the American Road Builders Association : (ARBA) and Underwriters Lab...

Characterization of stormwater runoff from bridges in North Carolina and the effects of bridge runoff on receiving streams

USGS Publications Warehouse

Wagner, Chad; Fitzgerald, Sharon; Lauffer, Matthew

2015-01-01

The presentation will provide an overview of a collaborative study between USGS, NC Department of Transportation and URS Corporation to characterize stormwater runoff from bridges in North Carolina and the effects of bridge runoff on receiving streams. This investigation measured bridge deck runoff from 15 bridges for 12-15 storms, stream water-quality data for baseflow and storm conditions at four of the bridge deck sites and streambed sediment chemistry upstream and downstream of 30 bridges across North Carolina. Background on why the study was conducted, objectives and scope and a general summary of the major results and conclusions will be presented.

Bridge element deterioration rates.

DOT National Transportation Integrated Search

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 deck wearing surfaces.

DOT National Transportation Integrated Search

2010-11-01

Several commercially available bridge deck overlay systems claim to be waterproof and reduce deterioration caused by chloride laden water from penetrating concrete bridge decks. An attempt was made to quantify the in-service waterproofing qualities o...

Bridge-Vehicle Impact Assessment

DOT National Transportation Integrated Search

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.

DOT National Transportation Integrated Search

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

NASA Astrophysics Data System (ADS)

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.

89. 22'X34' original vellum, VariableAngle Launcher 'ELEVATION OF LAUNCHER BRIDGE ...

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

89. 22'X34' original vellum, Variable-Angle Launcher 'ELEVATION OF LAUNCHER BRIDGE ON TEMPORARY SUPPORT' drawn at 1'=20'. (BUORD Sketch # 209786, PAPW 1932). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

Akashi-Kaikyo Bridge, Japan

NASA Image and Video Library

2015-08-10

The Akashi Kaikyo Bridge in Japan has the longest central span of any suspension bridge in the world at 1991 m. The total length of the bridge is 3911 m. It links the city of Kobe on the mainland of Honshu to Iwaya on Awaji Island, crossing the busy Akashi Strait. The image was acquired April 26, 2014, covers an area of 8.1 by 11.2 km, and is located at 34.6 degrees north, 135 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA19747

E.s.r., magnetic, optical and biological (SOD and antimicrobial) studies of imidazolate bridged Cu II-Zn II and Cu II-Ni II complexes with tris(2-amino ethyl)amine as capping ligand: a plausible model for superoxide dismutase

NASA Astrophysics Data System (ADS)

Singh, Nripendra; Shukla, K. K.; Patel, R. N.; Chauhan, U. K.; Shrivastava, R.

2003-11-01

X-band e.s.r. and optical absorption spectra of the imidazolate bridged heterobimetallic complexes [(tren)Cu-E-Im-Zn-(tren)](ClO 4) 3 and [(tren)Cu-E-Im-Ni-(tren)](ClO 4) 3, where trentris(2-aminoethyl)amine, E-Im=2-ethylimidazolate ion and the related mononuclear complexes [Cu(tren)](ClO 4) 2 and [(tren)Cu-E-ImH)](ClO 4) 2 have been described. Biological activities (superoxide dismutase and antimicrobial) have also been measured and compared with reported complexes.

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

PubMed

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 < 0.05) when the dominant knee was flexed to 135 ° (23.49% MVIC) versus the traditional 90 ° (75.34% MVIC), while gluteal activation remained similarly high (51.01% and 57.81% MVIC in the traditional position, versus 47.35% and 57.23% MVIC in the modified position for the gluteus maximus and medius, respectively). Modifying the traditional single-leg bridge by flexing the

23 CFR 650.409 - Evaluation of bridge inventory.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Evaluation of bridge inventory. 650.409 Section 650.409... BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.409 Evaluation of bridge inventory. (a) Sufficiency rating of bridges. Upon receipt and evaluation of the bridge...

23 CFR 650.409 - Evaluation of bridge inventory.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Evaluation of bridge inventory. 650.409 Section 650.409... BRIDGES, STRUCTURES, AND HYDRAULICS Highway Bridge Replacement and Rehabilitation Program § 650.409 Evaluation of bridge inventory. (a) Sufficiency rating of bridges. Upon receipt and evaluation of the bridge...

Halide/pseudohalide complexes of cadmium(II) with benzimidazole: Synthesis, crystal structures and fluorescence properties

NASA Astrophysics Data System (ADS)

Zhao, Hai-Yan; Yang, Fu-Li; Li, Na; Wang, Xiao-Jing

2017-11-01

Two new dinuclear Cd(II) complexes, [CdL1Cl2]2·H2O (1) and [CdL1(N3)2]2·CH3OH (2) and one dicyanamide bridged one-dimensional polynuclear network [CdL1(μ1,5-dca)dca]n (3) of the potentially tridentate NNN-donor Schiff base 2-((1H-benzimidazol-2-yl-ethylimino)-methyl)pyridine (L1) and another dinucler Cd(II) complex [CdL2Cl(dca)]2 (4) of a similar NNN-donor Schiff base ligand 2-((1H-benzimidazol-2-yl-propylimino)-methyl)pyridine (L2), have been synthesized and characterized by elemental analyses, IR and single crystal X-ray crystallography. The ligands L1 and L2 are [1 + 1] condensation products of pyridine-2-carbaldehyde with 2-aminoethyl-1H-benzimidazole and 2-aminopropyl-1H-benzimidazole, respectively. In the complexes 1 and 4 the two Cd(II) centers are held together by the bridged chloride ligands, while in 2 the two Cd(II) centers are bridged by μ1,1-azide ions. Complex 3 has a one-dimensional infinite chain structure in which Cd(II) ions are bridged by single dicyanamide groups in end-to-end fashion. All the metal centers have a distorted octahedral geometry and H-bonding or π⋯π interactions are operative to bind the complex units in the solid state. Furthermore, these complexes have been investigated by thermogravimetric analyses and fluorescence spectra.

Developing deterioration models for Nebraska bridges.

DOT National Transportation Integrated Search

2011-07-01

Nebraska Bridge Management System (NBMS) was developed in 1999 to assist in optimizing budget allocation for : the maintenance, rehabilitation and replacement needs of highway bridges. This requires the prediction of bridge : deterioration to calcula...

LTBP bridge performance primer.

DOT National Transportation Integrated Search

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...

Newport Pell Bridge traffic and revenue study

DOT National Transportation Integrated Search

2010-01-12

Jacobs Engineering conducted a traffic and toll revenue study for the Claiborne Pell Newport Bridge : (Newport Pell Bridge or Pell Bridge) upon the request of the Rhode Island Turnpike and Bridge : Authority (RITBA). This study is being c...

33 CFR 115.70 - Advance approval of bridges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 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...

33 CFR 115.70 - Advance approval of bridges.

Code of Federal Regulations, 2010 CFR

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...

The Simulation of Vibrations of Railway Beam Bridges in the Object-oriented Environment Delphi

NASA Astrophysics Data System (ADS)

Raspopov, Alexander; Artyomov, Vitaly; Rusu, Sergey

2010-01-01

The peculiarities of combination of finite-element method and equations of solid dynamics, the basic stages of development of the program complex Belinda for calculation of statics and dynamics of the rods constructions as applied to railway bridges are described.

Temporary bridge deck panels.

DOT National Transportation Integrated Search

2009-03-01

The research described here has resulted in the development of a simplistic and innovative interlocking : glulam bridge deck panel for use in temporary bridge deck applications. The key feature of this panel : system is the interlocking tongue and gr...

Bridge Scour Technology Transfer

DOT National Transportation Integrated Search

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...

Chesapeake City Bridge. Bridge Inspection Report Number 11B.

DTIC Science & Technology

1979-12-01

recommendations for th 1979 inspection of the Chesapeake City Bridge (Route designation , U.S. Route 213) which crosses the Chesappake and Delaware Canal...Los Arg4 .PASN4 . Mrkee. g14neaoos. Nevr,,r DE . Now York Oemnfto, overland PWn KS. Fh ~M% S0.mo- Tamp, TW=. F wia AMot ho d Jl 4O T, - kv Col. James G...1979 inspection of the Chesapeake City Bridge (Route designation , U.S. Route 213) which crosses the Chesapeake and Delaware Canal was undertaken for the

Development of a sustainable UHPC bridge deck for movable bridges : [research project capsule].

DOT National Transportation Integrated Search

2015-11-01

Louisiana has approximately 160 movable bridges, mostly in the southern part of the state, which : places Louisiana among states with the highest inventory of movable bridges in the nation. These : transportation arteries are important for the econom...

Bridging the Gap for High-Coherence, Strongly Coupled Superconducting Qubits

NASA Astrophysics Data System (ADS)

Yoder, Jonilyn; Kim, David; Baldo, Peter; Day, Alexandra; Fitch, George; Holihan, Eric; Hover, David; Samach, Gabriel; Weber, Steven; Oliver, William

Crossovers can play a critical role in increasing superconducting qubit device performance, as long as device coherence can be maintained even with the increased fabrication and circuit complexity. Specifically, crossovers can (1) enable a fully-connected ground plane, which reduces spurious modes and crosstalk in the circuit, and (2) increase coupling strength between qubits by facilitating interwoven qubit loops with large mutual inductances. Here we will describe our work at MIT Lincoln Laboratory to integrate superconducting air bridge crossovers into the fabrication of high-coherence capacitively-shunted superconducting flux qubits. We will discuss our process flow for patterning air bridges by resist reflow, and we will describe implementation of air bridges within our circuits. This research was funded in part by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA) and by the Assistant Secretary of Defense for Research and Engineering under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

Full-scale monitoring of wind and suspension bridge response

NASA Astrophysics Data System (ADS)

Snæbjörnsson, J. T.; Jakobsen, J. B.; Cheynet, E.; Wang, J.

2017-12-01

Monitoring of real structures is important for many reasons. For structures susceptible to environmental actions, full-scale observations can provide valuable information about the environmental conditions at the site, as well as the characteristics of the excitation acting on the structure. The recorded data, if properly analyzed, can be used to validate and/or update experiments and models used in the design of new structures, such as the load description and modelling of the structural response. Various aspects of full-scale monitoring are discussed in the paper and the full-scale wind engineering laboratory at the Lysefjord suspension bridge introduced. The natural excitation of the bridge comes from wind and traffic. The surrounding terrain is complex and its effect on the wind flow can only be fully studied on site, in full-scale. The monitoring program and associated data analysis are described. These include various studies of the relevant turbulence characteristics, identification of dynamic properties and estimation of wind- and traffic-induced response parameters. The overall monitoring activity also included a novel application of the remote optical sensing in bridge engineering, which is found to have an important potential to complement traditional “single-point” wind observations by sonic anemometers.

49 CFR 236.766 - Locking, movable bridge.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 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. ...

49 CFR 236.766 - Locking, movable bridge.

Code of Federal Regulations, 2010 CFR

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

DOT National Transportation Integrated Search

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.

DOT National Transportation Integrated Search

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 ...

Evaluation of a highway bridge constructed using high strength lightweight concrete bridge girders.

DOT National Transportation Integrated Search

2011-04-01

The purpose of this research was to characterize the performance of High Strength Lightweight Concrete (HSLW) in precast, prestressed bridge girders and to evaluate their performance in a highway bridge. The mechanical properties and long-term time-d...

Bridging: Locating Critical Connectors in a Network

PubMed Central

Valente, Thomas W.; Fujimoto, Kayo

2010-01-01

This paper proposes several measures for bridging in networks derived from Granovetter's (1973) insight that links which reduce distances in a network are important structural bridges. Bridging is calculated by systematically deleting links and calculating the resultant changes in network cohesion (measured as the inverse average path length). The average change for each node's links provides an individual level measure of bridging. We also present a normalized version which controls for network size and a network level bridging index. Bridging properties are demonstrated on hypothetical networks, empirical networks, and a set of 100 randomly generated networks to show how the bridging measure correlates with existing network measures such as degree, personal network density, constraint, closeness centrality, betweenness centrality, and vitality. Bridging and the accompanying methodology provide a family of new network measures useful for studying network structure, network dynamics, and network effects on substantive behavioral phenomenon. PMID:20582157

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

Treesearch

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...

Butterfly deformation modes in a photoexcited pyrazolate-bridged Pt complex measured by time-resolved x-ray scattering in solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haldrup, Kristoffer; Dohn, Asmus O.; Shelby, Megan L.

2016-08-27

Pyrazolate-bridged di-nuclear Pt complexes represent a series of molecules with tunable absorption and emission properties that can be directly modulated by structural factors, such as the Pt-Pt distance. However, direct experimental information regarding the structure of the emissive triplet excited state has remained scarce. Using time-resolved wide angle X-ray scattering (WAXS), the molecular structure of the triplet excited state for one of the complexes [Pt(ppy)(μ-tBu 2pz)] 2 was obtained in a dilute (0.5 mM) toluene solution utilizing the monochromatic X-ray beamline 11IDD of the Advanced Photon Source. The excited state structural analysis was carried out based on the results frommore » both transient WAXS measurements and DFT calculations to shed light on the primary structural changes, in particular the Pt-Pt distance and ligand rotation taking place following the photo-excitation of [Pt(ppy)(μ-tBu 2pz)] 2 in toluene solution. We find that in the triplet excited state a pronounced contraction along the Pt-Pt axis has taken place accompanied by rotational motions of ppy ligands toward one another. Our results suggest that the contraction is larger than what has previously been reported, but are in good agreement with recent theoretical efforts and suggest the ppy moieties as targets for rational synthesis aimed at tuning the excited-state structure and properties« less

Development of inspection robots for bridge cables.

PubMed

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.

Processor farming in two-level analysis of historical bridge

NASA Astrophysics Data System (ADS)

Krejčí, T.; Kruis, J.; Koudelka, T.; Šejnoha, M.

2017-11-01

This contribution presents a processor farming method in connection with a multi-scale analysis. In this method, each macro-scopic integration point or each finite element is connected with a certain meso-scopic problem represented by an appropriate representative volume element (RVE). The solution of a meso-scale problem provides then effective parameters needed on the macro-scale. Such an analysis is suitable for parallel computing because the meso-scale problems can be distributed among many processors. The application of the processor farming method to a real world masonry structure is illustrated by an analysis of Charles bridge in Prague. The three-dimensional numerical model simulates the coupled heat and moisture transfer of one half of arch No. 3. and it is a part of a complex hygro-thermo-mechanical analysis which has been developed to determine the influence of climatic loading on the current state of the bridge.

Spread prestressed concrete slab beam bridges.

DOT National Transportation Integrated Search

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...

Lean Construction Applications for Bridge Inspection

DOT National Transportation Integrated Search

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...

Modeling of interaction between cytochrome c and the WD domains of Apaf-1: bifurcated salt bridges underlying apoptosome assembly.

PubMed

Shalaeva, Daria N; Dibrova, Daria V; Galperin, Michael Y; Mulkidjanian, Armen Y

2015-05-27

Binding of cytochrome c, released from the damaged mitochondria, to the apoptotic protease activating factor 1 (Apaf-1) is a key event in the apoptotic signaling cascade. The binding triggers a major domain rearrangement in Apaf-1, which leads to oligomerization of Apaf-1/cytochrome c complexes into an apoptosome. Despite the availability of crystal structures of cytochrome c and Apaf-1 and cryo-electron microscopy models of the entire apoptosome, the binding mode of cytochrome c to Apaf-1, as well as the nature of the amino acid residues of Apaf-1 involved remain obscure. We investigated the interaction between cytochrome c and Apaf-1 by combining several modeling approaches. We have applied protein-protein docking and energy minimization, evaluated the resulting models of the Apaf-1/cytochrome c complex, and carried out a further analysis by means of molecular dynamics simulations. We ended up with a single model structure where all the lysine residues of cytochrome c that are known as functionally-relevant were involved in forming salt bridges with acidic residues of Apaf-1. This model has revealed three distinctive bifurcated salt bridges, each involving a single lysine residue of cytochrome c and two neighboring acidic resides of Apaf-1. Salt bridge-forming amino acids of Apaf-1 showed a clear evolutionary pattern within Metazoa, with pairs of acidic residues of Apaf-1, involved in bifurcated salt bridges, reaching their highest numbers in the sequences of vertebrates, in which the cytochrome c-mediated mechanism of apoptosome formation seems to be typical. The reported model of an Apaf-1/cytochrome c complex provides insights in the nature of protein-protein interactions which are hard to observe in crystallographic or electron microscopy studies. Bifurcated salt bridges can be expected to be stronger than simple salt bridges, and their formation might promote the conformational change of Apaf-1, leading to the formation of an apoptosome. Combination of

The neural correlates of morphological complexity processing: Detecting structure in pseudowords.

PubMed

Schuster, Swetlana; Scharinger, Mathias; Brooks, Colin; Lahiri, Aditi; Hartwigsen, Gesa

2018-06-01

Morphological complexity is a highly debated issue in visual word recognition. Previous neuroimaging studies have shown that speakers are sensitive to degrees of morphological complexity. Two-step derived complex words (bridging through bridge N  > bridge V  > bridging) led to more enhanced activation in the left inferior frontal gyrus than their 1-step derived counterparts (running through run V  > running). However, it remains unclear whether sensitivity to degrees of morphological complexity extends to pseudowords. If this were the case, it would indicate that abstract knowledge of morphological structure is independent of lexicality. We addressed this question by investigating the processing of two sets of pseudowords in German. Both sets contained morphologically viable two-step derived pseudowords differing in the number of derivational steps required to access an existing lexical representation and therefore the degree of structural analysis expected during processing. Using a 2 × 2 factorial design, we found lexicality effects to be distinct from processing signatures relating to structural analysis in pseudowords. Semantically-driven processes such as lexical search showed a more frontal distribution while combinatorial processes related to structural analysis engaged more parietal parts of the network. Specifically, more complex pseudowords showed increased activation in parietal regions (right superior parietal lobe and left precuneus) relative to pseudowords that required less structural analysis to arrive at an existing lexical representation. As the two sets were matched on cohort size and surface form, these results highlight the role of internal levels of morphological structure even in forms that do not possess a lexical representation. © 2018 Wiley Periodicals, Inc.

77 FR 16784 - General Bridge Regulation; Amendment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-22

...] RIN 1625-AB36 General Bridge Regulation; Amendment AGENCY: Coast Guard, DHS. ACTION: Proposed rule... bridge regulations. The rulemaking was initiated to clarify the statutory responsibilities of bridge owners to remove their bridges from navigable waterways when they are no longer being used for land...

Hydrodynamic forces on inundated bridge decks

DOT National Transportation Integrated Search

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 ...

Hydraulic forces on submerged bridge decks.

DOT National Transportation Integrated Search

2008-09-01

Bridge decks can be subjected to large horizontal forces when overtopping occurs. These forces may result in the displacement of bridge decks from the bents. This paper reports on the results of a laboratory study of horizontal forces on bridge decks...

Glycosylinositol phosphorylceramides from Rosa cell cultures are boron-bridged in the plasma membrane and form complexes with rhamnogalacturonan II.

PubMed

Voxeur, Aline; Fry, Stephen C

2014-07-01

Boron (B) is essential for plant cell-wall structure and membrane functions. Compared with its role in cross-linking the pectic domain rhamnogalacturonan II (RG-II), little information is known about the biological role of B in membranes. Here, we investigated the involvement of glycosylinositol phosphorylceramides (GIPCs), major components of lipid rafts, in the membrane requirement for B. Using thin-layer chromatography and mass spectrometry, we first characterized GIPCs from Rosa cell culture. The major GIPC has one hexose residue, one hexuronic acid residue, inositol phosphate, and a ceramide moiety with a C18 trihydroxylated mono-unsaturated long-chain base and a C24 monohydroxylated saturated fatty acid. Disrupting B bridging (by B starvation in vivo or by treatment with cold dilute HCl or with excess borate in vitro) enhanced the GIPCs' extractability. As RG-II is the main B-binding site in plants, we investigated whether it could form a B-centred complex with GIPCs. Using high-voltage paper electrophoresis, we showed that addition of GIPCs decreased the electrophoretic mobility of radiolabelled RG-II, suggesting formation of a GIPC-B-RG-II complex. Last, using polyacrylamide gel electrophoresis, we showed that added GIPCs facilitate RG-II dimerization in vitro. We conclude that B plays a structural role in the plasma membrane. The disruption of membrane components by high borate may account for the phytotoxicity of excess B. Moreover, the in-vitro formation of a GIPC-B-RG-II complex gives the first molecular explanation of the wall-membrane attachment sites observed in vivo. Finally, our results suggest a role for GIPCs in the RG-II dimerization process. © 2014 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

Development of Inspection Robots for Bridge Cables

PubMed Central

Kim, Se-Hoon; 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. PMID:24459453

49 CFR 237.55 - Railroad bridge supervisors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Railroad bridge supervisors. 237.55 Section 237.55..., DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Qualifications and Designations of Responsible Persons § 237.55 Railroad bridge supervisors. A railroad bridge supervisor shall be a person, regardless of...

23 CFR 650.307 - Bridge inspection organization.

Code of Federal Regulations, 2010 CFR

2010-04-01

... bridges located on public roads that are fully or partially located within the State's boundaries, except... inspected, all highway bridges located on public roads that are fully or partially located within the... preparation and maintenance of a bridge inventory. (2) Bridge inspections, reports, load ratings and other...

49 CFR 237.55 - Railroad bridge supervisors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Railroad bridge supervisors. 237.55 Section 237.55..., DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Qualifications and Designations of Responsible Persons § 237.55 Railroad bridge supervisors. A railroad bridge supervisor shall be a person, regardless of...

The South Carolina bridge-scour envelope curves

USGS Publications Warehouse

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.

Copper(II) cyanido-bridged bimetallic nitroprusside-based complexes: Syntheses, X-ray structures, magnetic properties, 57Fe Mössbauer spectroscopy and thermal studies

NASA Astrophysics Data System (ADS)

Trávníček, Zdeněk; Herchel, Radovan; Mikulík, Jiří; Zbořil, Radek

2010-05-01

Three heterobimetallic cyanido-bridged copper(II) nitroprusside-based complexes of the compositions [Cu(tet)Fe(CN) 5NO]·H 2O ( 1), where tet= N,N' -bis(3-aminopropyl)ethylenediamine, [Cu(hto)Fe(CN) 5NO]·2H 2O ( 2), where hto=1,3,6,9,11,14-hexaazatricyclo[12.2.1.1 6,9]octadecane and [Cu(nme) 2Fe(CN) 5NO]·H 2O ( 3), where nme= N-methylethylenediamine, were synthesized and characterized by elemental analyses, 57Fe Mössbauer and FTIR spectroscopies, thermal analysis, magnetic measurements and single-crystal X-ray analysis. The products of thermal degradation processes of 2 and 3 were studied by XRD, 57Fe Mössbauer spectroscopy, SEM and EDS, and they were identified as mixtures of CuFe 2O 4 and CuO.

Stabilization of electrically conducting capillary bridges using feedback control of radial electrostatic stresses and the shapes of extended bridges

NASA Astrophysics Data System (ADS)

Marr-Lyon, Mark J.; Thiessen, David B.; Blonigen, Florian J.; Marston, Philip L.

2000-05-01

Electrically conducting, cylindrical liquid bridges in a density-matched, electrically insulating bath were stabilized beyond the Rayleigh-Plateau (RP) limit using electrostatic stresses applied by concentric ring electrodes. A circular liquid cylinder of length L and radius R in real or simulated zero gravity becomes unstable when the slenderness S=L/2R exceeds π. The initial instability involves the growth of the so-called (2, 0) mode of the bridge in which one side becomes thin and the other side rotund. A mode-sensing optical system detects the growth of the (2, 0) mode and an analog feedback system applies the appropriate voltages to a pair of concentric ring electrodes positioned near the ends of the bridge in order to counter the growth of the (2, 0) mode and prevent breakup of the bridge. The conducting bridge is formed between metal disks which are grounded. Three feedback algorithms were tested and each found capable of stabilizing a bridge well beyond the RP limit. All three algorithms stabilized bridges having S as great as 4.3 and the extended bridges broke immediately when feedback was terminated. One algorithm was suitable for stabilization approaching S=4.493… where the (3, 0) mode is predicted to become unstable for cylindrical bridges. For that algorithm the equilibrium shapes of bridges that were slightly under or over inflated corresponded to solutions of the Young-Laplace equation with negligible electrostatic stresses. The electrical conductivity of the bridge liquid need not be large. The conductivity was associated with salt added to the aqueous bridge liquid.

33 CFR 118.140 - Painting bridge piers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 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...

49 CFR 237.53 - Railroad bridge inspectors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Railroad bridge inspectors. 237.53 Section 237.53..., DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Qualifications and Designations of Responsible Persons § 237.53 Railroad bridge inspectors. A railroad bridge inspector shall be a person who is determined by...

33 CFR 118.140 - Painting bridge piers.

Code of Federal Regulations, 2010 CFR

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...

49 CFR 237.53 - Railroad bridge inspectors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Railroad bridge inspectors. 237.53 Section 237.53..., DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Qualifications and Designations of Responsible Persons § 237.53 Railroad bridge inspectors. A railroad bridge inspector shall be a person who is determined by...

Estimation of the full-field dynamic response of a floating bridge using Kalman-type filtering algorithms

NASA Astrophysics Data System (ADS)

Petersen, Ø. W.; Øiseth, O.; Nord, T. S.; Lourens, E.

2018-07-01

Numerical predictions of the dynamic response of complex structures are often uncertain due to uncertainties inherited from the assumed load effects. Inverse methods can estimate the true dynamic response of a structure through system inversion, combining measured acceleration data with a system model. This article presents a case study of full-field dynamic response estimation of a long-span floating bridge: the Bergøysund Bridge in Norway. This bridge is instrumented with a network of 14 triaxial accelerometers. The system model consists of 27 vibration modes with natural frequencies below 2 Hz, obtained from a tuned finite element model that takes the fluid-structure interaction with the surrounding water into account. Two methods, a joint input-state estimation algorithm and a dual Kalman filter, are applied to estimate the full-field response of the bridge. The results demonstrate that the displacements and the accelerations can be estimated at unmeasured locations with reasonable accuracy when the wave loads are the dominant source of excitation.

33 CFR 115.50 - Application for bridge permits.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Application for bridge permits... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.50 Application for bridge permits. (a) Application. An application for authorization to construct a bridge across navigable waters of...

49 CFR 237.101 - Scheduling of bridge inspections.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Scheduling of bridge inspections. 237.101 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.101 Scheduling of bridge inspections. (a) Each bridge management program shall include a provision for scheduling an...

49 CFR 237.101 - Scheduling of bridge inspections.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Scheduling of bridge inspections. 237.101 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.101 Scheduling of bridge inspections. (a) Each bridge management program shall include a provision for scheduling an...

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

DOT National Transportation Integrated Search

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...

Dinuclear complexes containing linear M-F-M [M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)] bridges: trends in structures, antiferromagnetic superexchange interactions, and spectroscopic properties.

PubMed

Reger, Daniel L; Pascui, Andrea E; Smith, Mark D; Jezierska, Julia; Ozarowski, Andrew

2012-11-05

The reaction of M(BF(4))(2)·xH(2)O, where M is Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II), with the new ditopic ligand m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (L(m)*) leads to the formation of monofluoride-bridged dinuclear metallacycles of the formula [M(2)(μ-F)(μ-L(m)*)(2)](BF(4))(3). The analogous manganese(II) species, [Mn(2)(μ-F)(μ-L(m)*)(2)](ClO(4))(3), was isolated starting with Mn(ClO(4))(2)·6H(2)O using NaBF(4) as the source of the bridging fluoride. In all of these complexes, the geometry around the metal centers is trigonal bipyramidal, and the fluoride bridges are linear. The (1)H, (13)C, and (19)F NMR spectra of the zinc(II) and cadmium(II) compounds and the (113)Cd NMR of the cadmium(II) compound indicate that the metallacycles retain their structure in acetonitrile and acetone solution. The compounds with M = Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) are antiferromagnetically coupled, although the magnitude of the coupling increases dramatically with the metal as one moves to the right across the periodic table: Mn(II) (-6.7 cm(-1)) < Fe(II) (-16.3 cm(-1)) < Co(II) (-24.1 cm(-1)) < Ni(II) (-39.0 cm(-1)) ≪ Cu(II) (-322 cm(-1)). High-field EPR spectra of the copper(II) complexes were interpreted using the coupled-spin Hamiltonian with g(x) = 2.150, g(y) = 2.329, g(z) = 2.010, D = 0.173 cm(-1), and E = 0.089 cm(-1). Interpretation of the EPR spectra of the iron(II) and manganese(II) complexes required the spin Hamiltonian using the noncoupled spin operators of two metal ions. The values g(x) = 2.26, g(y) = 2.29, g(z) = 1.99, J = -16.0 cm(-1), D(1) = -9.89 cm(-1), and D(12) = -0.065 cm(-1) were obtained for the iron(II) complex and g(x) = g(y) = g(z) = 2.00, D(1) = -0.3254 cm(-1), E(1) = -0.0153, J = -6.7 cm(-1), and D(12) = 0.0302 cm(-1) were found for the manganese(II) complex. Density functional theory (DFT) calculations of the exchange integrals and the zero-field splitting on manganese(II) and iron(II) ions were performed

Simplified bridge load rating methodology using the national bridge inventory file : user manual

DOT National Transportation Integrated Search

1988-08-01

The purpose of this research was to develop a computerized system to determine the adequacy of a bridge or group of bridges to carry specified overload vehicles. The system utilizes two levels of analysis. The Level 1 analysis is the basic rating sys...

Simplified bridge load rating methodology using the national bridge inventory file : program listing

DOT National Transportation Integrated Search

1987-08-01

The purpose of this research was to develop a computerized system to determine the adequacy of a bridge or group of bridges to carry specified overload vehicles. The system utilizes two levels of analysis. The Level 1 analysis is the basic rating sys...

Bridge deficiency metric refinement : longer-term planning for state and locally-owned bridges.

DOT National Transportation Integrated Search

2010-06-01

The focus of this study was to devise a prioritization scheme for locally-owned bridges and to extend the planning time horizon for state-owned bridges. The inherent nature of the local and county structures prevents a direct application of the formu...

49 CFR 236.713 - Bridge, movable.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Bridge, movable. 236.713 Section 236.713 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Bridge, movable. That section of a structure bridging a navigable waterway so designed that it may be...

49 CFR 236.713 - Bridge, movable.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Bridge, movable. 236.713 Section 236.713 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Bridge, movable. That section of a structure bridging a navigable waterway so designed that it may be...

The Bridge Project: Connecting Home, School, and Community for Mexican Immigrant Children

ERIC Educational Resources Information Center

McElvain, Cheryl Marie

2015-01-01

This study examines the academic and psychosocial effects of the Bridge Project after-school program on 25 prekindergarten through 6th-grade English language learner Mexican immigrant children and their families living in an affordable housing complex in the San Francisco Bay Area. The results of the study show that the program increased the…

33 CFR 118.90 - Bridges crossing channel obliquely.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 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...

49 CFR 237.107 - Conduct of bridge inspections.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Conduct of bridge inspections. 237.107 Section 237... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.107 Conduct of bridge inspections. Bridge inspections shall be conducted under the direct supervision of a designated...

33 CFR 118.90 - Bridges crossing channel obliquely.

Code of Federal Regulations, 2010 CFR

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...

49 CFR 237.107 - Conduct of bridge inspections.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Conduct of bridge inspections. 237.107 Section 237... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.107 Conduct of bridge inspections. Bridge inspections shall be conducted under the direct supervision of a designated...

33 CFR 115.50 - Application for bridge permits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Application for bridge permits... BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.50 Application for bridge permits. (a) Approval of plans. An application for authorization to construct a bridge across navigable waters...

Bridge deck fogging system : evaluation of field implementation of a fogging system used during bridge deck construction.

DOT National Transportation Integrated Search

2008-01-01

The objective of this research was to implement and evaluate a fogging system used to provide initial cure for a concrete bridge deck construction project. To accomplish this, Bridges 5500 and 5701 along NM26 were selected. Bridge 5500 was placed usi...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... Bridge and the San Francisco-Oakland Bay Bridge, San Francisco Bay, California. 165.1187 Section 165.1187... Limited Access Areas Eleventh Coast Guard District § 165.1187 Security Zones; Golden Gate Bridge and the San Francisco-Oakland Bay Bridge, San Francisco Bay, California. (a) Location. All waters extending...

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

Code of Federal Regulations, 2010 CFR

2010-07-01

... Bridge and the San Francisco-Oakland Bay Bridge, San Francisco Bay, California. 165.1187 Section 165.1187... Limited Access Areas Eleventh Coast Guard District § 165.1187 Security Zones; Golden Gate Bridge and the San Francisco-Oakland Bay Bridge, San Francisco Bay, California. (a) Location. All waters extending...

Reliability Modeling of Double Beam Bridge Crane

NASA Astrophysics Data System (ADS)

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toriumi, Shin; Katsukawa, Yukio; Cheung, Mark C. M., E-mail: shin.toriumi@nao.ac.jp

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, andmore » 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.« less

ROAD BRIDGES IN MINAMI-SANRIKU WASHED AWAY IN THE MARCH 11th 2011 GREAT EAST JAPAN EARTHQUAKE AND TSUNAMI

NASA Astrophysics Data System (ADS)

Aglipay, Mary Roxanne I.; Konagai, Kazuo; Kyokawa, Hiroyuki; Keshab, Sharma

On March 11th, 2011, Minami-Sanriku, located in the northeastern coast of Japan was severely inundated by the tsunami that followed the Great East Japan Earthquake on March 11, 2011. Road bridges near the coastlines in this area have been extensively damaged with their decks being overturned or carried over long distances. An attempt was made to deduce as rational scenarios as possible before remaining debris was cleaned up. Though the reasons for the washout of bridges can be many and complex, it is to be noted that bridge decks have hollows for the optimum light-weight solution, which fact eventually allowed the bridge decks to be carried over remarkable distances. Poor connection details and cavities, hollows between deck beams, are considered to have facilitated overturning due to uplift forces.

33 CFR 118.65 - Lights on fixed bridges.

Code of Federal Regulations, 2010 CFR

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...

33 CFR 118.70 - Lights on swing bridges.

Code of Federal Regulations, 2010 CFR

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...

Multiple Two-Way Time Message Exchange (TTME) Time Synchronization for Bridge Monitoring Wireless Sensor Networks

PubMed Central

Shi, Fanrong; Tuo, Xianguo; Yang, Simon X.; Li, Huailiang; Shi, Rui

2017-01-01

Wireless sensor networks (WSNs) have been widely used to collect valuable information in Structural Health Monitoring (SHM) of bridges, using various sensors, such as temperature, vibration and strain sensors. Since multiple sensors are distributed on the bridge, accurate time synchronization is very important for multi-sensor data fusion and information processing. Based on shape of the bridge, a spanning tree is employed to build linear topology WSNs and achieve time synchronization in this paper. Two-way time message exchange (TTME) and maximum likelihood estimation (MLE) are employed for clock offset estimation. Multiple TTMEs are proposed to obtain a subset of TTME observations. The time out restriction and retry mechanism are employed to avoid the estimation errors that are caused by continuous clock offset and software latencies. The simulation results show that the proposed algorithm could avoid the estimation errors caused by clock drift and minimize the estimation error due to the large random variable delay jitter. The proposed algorithm is an accurate and low complexity time synchronization algorithm for bridge health monitoring. PMID:28471418

Multiple Two-Way Time Message Exchange (TTME) Time Synchronization for Bridge Monitoring Wireless Sensor Networks.

PubMed

Shi, Fanrong; Tuo, Xianguo; Yang, Simon X; Li, Huailiang; Shi, Rui

2017-05-04

Wireless sensor networks (WSNs) have been widely used to collect valuable information in Structural Health Monitoring (SHM) of bridges, using various sensors, such as temperature, vibration and strain sensors. Since multiple sensors are distributed on the bridge, accurate time synchronization is very important for multi-sensor data fusion and information processing. Based on shape of the bridge, a spanning tree is employed to build linear topology WSNs and achieve time synchronization in this paper. Two-way time message exchange (TTME) and maximum likelihood estimation (MLE) are employed for clock offset estimation. Multiple TTMEs are proposed to obtain a subset of TTME observations. The time out restriction and retry mechanism are employed to avoid the estimation errors that are caused by continuous clock offset and software latencies. The simulation results show that the proposed algorithm could avoid the estimation errors caused by clock drift and minimize the estimation error due to the large random variable delay jitter. The proposed algorithm is an accurate and low complexity time synchronization algorithm for bridge health monitoring.

Bridges and Equipment

DTIC Science & Technology

2009-09-15

in.) Tire pressure +7 kPa (+1 psig) Ambient or chamber temperature +2 °C (+3.6 °F) Relative humidity (RH) +1% reading Wind speed +1 kt Distance... eccentric ), and number of bridge crossings. (4) Vehicle stopping data including speed, position, and direction on the bridge. (5) Ambient...fashion for initial trials, and then loads should be applied eccentrically . The load configuration as it was applied to the raft will be documented

A data management infrastructure for bridge monitoring

NASA Astrophysics Data System (ADS)

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.

Standard practice for washing and cleaning concrete bridge decks and substructure bridge seats including bridge bearings and expansion joints to prevent structural deterioration.

DOT National Transportation Integrated Search

2013-12-01

This study is a supplement to a previous study of bridge washing practices that focused on steel : superstructures. This study examined the perceived costs and benefits of routine washing of both : steel and concrete bridges, with emphasis on substru...

Rapid-estimation method for assessing scour at highway bridges

USGS Publications Warehouse

Holnbeck, Stephen R.

1998-01-01

A method was developed by the U.S. Geological Survey for rapid estimation of scour at highway bridges using limited site data and analytical procedures to estimate pier, abutment, and contraction scour depths. The basis for the method was a procedure recommended by the Federal Highway Administration for conducting detailed scour investigations, commonly referred to as the Level 2 method. Using pier, abutment, and contraction scour results obtained from Level 2 investigations at 122 sites in 10 States, envelope curves and graphical relations were developed that enable determination of scour-depth estimates at most bridge sites in a matter of a few hours. Rather than using complex hydraulic variables, surrogate variables more easily obtained in the field were related to calculated scour-depth data from Level 2 studies. The method was tested by having several experienced individuals apply the method in the field, and results were compared among the individuals and with previous detailed analyses performed for the sites. Results indicated that the variability in predicted scour depth among individuals applying the method generally was within an acceptable range, and that conservatively greater scour depths generally were obtained by the rapid-estimation method compared to the Level 2 method. The rapid-estimation method is considered most applicable for conducting limited-detail scour assessments and as a screening tool to determine those bridge sites that may require more detailed analysis. The method is designed to be applied only by a qualified professional possessing knowledge and experience in the fields of bridge scour, hydraulics, and flood hydrology, and having specific expertise with the Level 2 method.

Dynamic properties of molecular motors in burnt-bridge models

NASA Astrophysics Data System (ADS)

Artyomov, Maxim N.; Morozov, Alexander Yu; Pronina, Ekaterina; Kolomeisky, Anatoly B.

2007-08-01

Dynamic properties of molecular motors that fuel their motion by actively interacting with underlying molecular tracks are studied theoretically via discrete-state stochastic 'burnt-bridge' models. The transport of the particles is viewed as an effective diffusion along one-dimensional lattices with periodically distributed weak links. When an unbiased random walker passes the weak link it can be destroyed ('burned') with probability p, providing a bias in the motion of the molecular motor. We present a theoretical approach that allows one to calculate exactly all dynamic properties of motor proteins, such as velocity and dispersion, under general conditions. It is found that dispersion is a decreasing function of the concentration of bridges, while the dependence of dispersion on the burning probability is more complex. Our calculations also show a gap in dispersion for very low concentrations of weak links or for very low burning probabilities which indicates a dynamic phase transition between unbiased and biased diffusion regimes. Theoretical findings are supported by Monte Carlo computer simulations.

Virtual Bridge Design Challenge

ERIC Educational Resources Information Center

Mitts, Charles R.

2013-01-01

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

Strengthening bridges using composite materials.

DOT National Transportation Integrated Search

1998-03-01

The objective of this research project is to outline methodologies for using Fiber Reinforced Polymer (FRP) composites to strengthen and rehabilitate reinforced concrete bridge elements. : Infrastructure deterioration and bridge strengthening techniq...

The Social Work Role in Reducing 30-Day Readmissions: The Effectiveness of the Bridge Model of Transitional Care.

PubMed

Alvarez, Renae; Ginsburg, Jacob; Grabowski, Jessica; Post, Sharon; Rosenberg, Walter

2016-04-01

The hospital experience is taxing and confusing for patients and their families, particularly those with limited economic and social resources. This complexity often leads to disengagement, poor adherence to the plan of care, and high readmission rates. Novel approaches to addressing the complexities of transitional care are emerging as possible solutions. The Bridge Model is a person-centered, social work-led, interdisciplinary transitional care intervention that helps older adults safely transition from the hospital back to their homes and communities. The Bridge Model combines 3 key components-care coordination, case management, and patient engagement-which provide a seamless transition during this stressful time and improve the overall quality of transitional care for older adults, including reducing hospital readmissions. The post Affordable Care Act (ACA) and managed care environment's emphasis on value and quality support further development and expansion of transitional care strategies, such as the Bridge Model, which offer promising avenues to fulfil the triple aim by improving the quality of individual patient care while also impacting population health and controlling per capita costs.

49 CFR 237.111 - Review of bridge inspection reports.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Review of bridge inspection reports. 237.111... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.111 Review of bridge inspection reports. Bridge inspection reports shall be reviewed by railroad bridge supervisors and railroad...

49 CFR 237.111 - Review of bridge inspection reports.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Review of bridge inspection reports. 237.111... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.111 Review of bridge inspection reports. Bridge inspection reports shall be reviewed by railroad bridge supervisors and railroad...

Preservation treatment for wood bridge application

Treesearch

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

2009-01-01

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

Remediation: Higher Education's Bridge to Nowhere

ERIC Educational Resources Information Center

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…

Characterization of stormwater runoff from bridges in North Carolina and the effects of bridge deck runoff on receiving streams

USGS Publications Warehouse

Wagner, Chad R.; Fitzgerald, Sharon A.; Sherrell, Roy D.; Harned, Douglas A.; Staub, Erik L.; Pointer, Brian H.; Wehmeyer, Loren L.

2011-01-01

In 2008, the North Carolina General Assembly passed House Bill 2436 that required the North Carolina Department of Transportation (NCDOT) to study the water-quality effects of bridges on receiving streams. In response, the NCDOT and the U.S. Geological Survey (USGS) collaborated on a study to provide information necessary to address the requirements of the Bill. To better understand the effects of stormwater runoff from bridges on receiving streams, the following tasks were performed: (1) characterize stormwater runoff quality and quantity from a representative selection of bridges in North Carolina; (2) measure stream water quality upstream from selected bridges to compare bridge deck stormwater concentrations and loads to stream constituent concentrations and loads; and (3) determine if the chemistry of bed sediments upstream and downstream from selected bridges differs substantially based on presence or absence of a best management practice for bridge runoff.

Estimation of potential bridge scour at bridges on state routes in South Dakota, 2003-07

USGS Publications Warehouse

Thompson, Ryan F.; Fosness, Ryan L.

2008-01-01

Flowing water can erode (scour) soils and cause structural failure of a bridge by exposing or undermining bridge foundations (abutments and piers). A rapid scour-estimation technique, known as the level-1.5 method and developed by the U.S. Geological Survey, was used to evaluate potential scour at bridges in South Dakota in a study conducted in cooperation with the South Dakota Department of Transportation. This method was used during 2003-07 to estimate scour for the 100-year and 500-year floods at 734 selected bridges managed by the South Dakota Department of Transportation on State routes in South Dakota. Scour depths and other parameters estimated from the level-1.5 analyses are presented in tabular form. Estimates of potential contraction scour at the 734 bridges ranged from 0 to 33.9 feet for the 100-year flood and from 0 to 35.8 feet for the 500-year flood. Abutment scour ranged from 0 to 36.9 feet for the 100-year flood and from 0 to 45.9 feet for the 500-year flood. Pier scour ranged from 0 to 30.8 feet for the 100-year flood and from 0 to 30.7 feet for the 500-year flood. The scour depths estimated by using the level-1.5 method can be used by the South Dakota Department of Transportation and others to identify bridges that may be susceptible to scour. Scour at 19 selected bridges also was estimated by using the level-2 method. Estimates of contraction, abutment, and pier scour calculated by using the level-1.5 and level-2 methods are presented in tabular and graphical formats. Compared to level-2 scour estimates, the level-1.5 method generally overestimated scour as designed, or in a few cases slightly underestimated scour. Results of the level-2 analyses were used to develop regression equations for change in head and average velocity through the bridge opening. These regression equations derived from South Dakota data are compared to similar regression equations derived from Montana and Colorado data. Future level-1.5 scour investigations in South

Investigation of Aerodynamic Interference between Twin Deck Bridges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sitek, M. A.; Bojanowski, C.; Lottes, S. A.

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 themore » 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

Penile skin bridges: causes and prevention.

PubMed

Kamal, Baher A

2009-01-01

The pathogenesis and methods of prevention of penile skin bridges are discussed, with a review of the literature. This was a retrospective study on 57 adult men who presented with penile skin bridges at King Fahd University Hospital, Khobar, Saudi Arabia, over a period of approximately 22 years. All patients gave a history of circumcision during the first month after birth. The bridges were surgically excised. The skin bridges were single (23 patients) or multiple (34 patients). Their edges were attached to the distal penile shaft proximally and the glans distally. Their width varied from 1 mm to 3 cm. They were all successfully excised under local or general anesthesia. Penile skin bridges are a rare complication of neonatal circumcision. They are caused by skin adhesions that occur during childhood. With aging, the adhesions separate partially at the corona to form bridges. Careful suturing and good dressing at the time of circumcision are simple procedures that can prevent adherence of the distal prepetual skin flap to the glans penis.

Structural health monitoring of Lindquist bridge

NASA Astrophysics Data System (ADS)

Sargent, D. D.; Murison, E. R.; Bakht, B.; Mufti, A. A.

2007-04-01

Many forestry bridges in Canada are typically single-lane, single span structures with two steel plate girders and a deck comprising of precast reinforced concrete panels. The concept of arching in deck slabs was utilized in the steel-free precast panels used in the Lindquist Bridge in British Columbia, Canada. The panels were completely devoid of tensile reinforcement and transverse confinement to the panels was provided by external steel straps. After the bridge was constructed in 1998, electrical strain gauges were installed on the girders and straps. Static and dynamic load tests were performed. The cracks on the top and bottom of the deck were mapped in 1999 and 2003. In 2006, a load test and crack mapping were performed on the bridge. The strain readings in the straps were compared with the data obtained 8 years prior. After analysis of the strain gauge readings, conclusions were drawn on the performance of the bridge. The cracks were formed to accommodate arching action and it was concluded that the bridge is still performing as it was designed.

Evaluation of the service performance of bridge components.

DOT National Transportation Integrated Search

2004-08-01

This study was initiated to provide review of common bridges to determine the performance of their components. Seven bridge types were selected that constituted 85 % of the Kentucky Transportation Cabinet (KYTC) bridge inventory. 319 bridges were ins...

Bridge inspection / washing program : bridge drainage program

DOT National Transportation Integrated Search

2002-02-01

The Rhode Island Department of Transportation, Operations Division is responsible for operation and maintenance of roads and bridges, and construction of highway and multi-modal projects to improve the transportation system of our state. One of the m...

The Importance of Bridging

ERIC Educational Resources Information Center

Zamboni, Camilla

2014-01-01

In this article, I will discuss the importance of the fundamental aspect of "bridging" in the wider context of language teaching. I will use "bridging" particularly in terms of cultural differences and underline the pivotal role of specific techniques, in a language class as well as in a pedagogy class or seminar, to help…

Time rate of local scour at complex bridge piers field and laboratory analyses : final report, April 2009.

DOT National Transportation Integrated Search

2009-04-01

A local scour evolution field study was conducted under this contract. One of the piers on the A1A Bridge over the Intracoastal Waterway (ICCW) in Fort Pierce, Florida was selected for the test site. The existing local scour hole was filled with sand...

Vehicle - Bridge interaction, comparison of two computing models

NASA Astrophysics Data System (ADS)

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.

Phase and widening construction of steel bridges : [summary].

DOT National Transportation Integrated Search

2014-03-01

Maintaining traffic flow for bridge widening and replacement projects often requires bridges to be constructed in phases so that traffic can travel on one : portion of the bridge while another portion is being : constructed. The bridge portions are t...

Seismic response of precast segmental bridge superstructures.

DOT National Transportation Integrated Search

2006-12-01

Precast segmental construction of bridges can accelerate construction and minimize the cost of bridges in highly congested urban environments and environmentally sensitive regions. Despite their proven benefits, the use of precast segmental bridges i...

Syntheses, crystal structures, and magnetic properties of four new cyano-bridged bimetallic complexes based on the mer-[Fe(III)(qcq)(CN)3]- building block.

PubMed

Shen, Xiaoping; Zhou, Hongbo; Yan, Jiahao; Li, Yanfeng; Zhou, Hu

2014-01-06

Four new cyano-bridged bimetallic complexes, [{Mn(III)(salen)}2{Fe(III)(qcq)(CN)3}2]n·3nCH3CN·nH2O (1) [salen = N,N'-ethylenebis(salicylideneiminato) dianion; qcq(-) = 8-(2-quinoline-2-carboxamido)quinoline anion], [{Mn(III)(salpn)}2{Fe(III)(qcq)(CN)3}2]n·4nH2O (2) [salpn = N,N'-1,2-propylenebis(salicylideneiminato)dianion], [{Mn(II)(bipy)(CH3OH)}{Fe(III)(qcq)(CN)3}2]2·2H2O·2CH3OH (3) (bipy = 2,2'-bipyridine), and [{Mn(II)(phen)2}{Fe(III)(qcq)(CN)3}2]·CH3CN·2H2O (4) (phen = 1,10-phenanthroline) have been synthesized and characterized both structurally and magnetically. The structures of 1 and 2 are both unique 1-D linear branch chains with additional structural units of {Mn(III)(salen/salpn)}{Fe(III)(qcq)(CN)3} dangling on the sides. In contrast, 3 and 4 are cyano-bridged bimetallic hexanuclear and trinuclear clusters, respectively. The intermolecular short contacts such as π-π interactions and hydrogen bonds extend 1-4 into high dimensional supermolecular networks. Magnetic investigation reveals the dominant intramolecular antiferromagnetic interactions in 1, 3, and 4, while ferromagnetic and antiferromagnetic interactions coexist in 2. Alternating current measurement at low temperature indicates the existence of slow magnetic relaxation in 1 and 2, which should be due to the single ion anisotropy of Mn(III).

Uncontrolled concrete bridge parapet cracking.

DOT National Transportation Integrated Search

2013-06-01

The Ohio Department of Transportation has recently identified the problem of wide-spread premature cracking of concrete bridge : parapets throughout its District 12 region (Northeast Ohio). Many of the bridge decks that contain these prematurely crac...

Virginia Bridge Information Systems Laboratory.

DOT National Transportation Integrated Search

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...

Integrated 3D bridge-condition visualization (BCV) to facilitate element-based bridge condition rating (EBCR).

DOT National Transportation Integrated Search

2015-11-01

Routine inspection and maintenance records are essential for bridges to function well throughout their intended lifespan. : Although existing bridge management systems are efficient at data storage, it is difficult to conduct comprehensive data : ana...

Key Royale bridge five year evaluation : [summary].

DOT National Transportation Integrated Search

2013-06-01

The Florida Department of Transportation (FDOT) : maintains more than 6,500 bridges. Considering : the expense of repair and replacement of bridges, : extending their durability and service life is : important. Of special concern for bridges in : mar...

Precast alternative for flat slab bridges : final report.

DOT National Transportation Integrated Search

2013-10-26

The cast-in-place (CIP) concrete slab bridge and the hollow core flat slab bridge are two very common bridge types utilized by the : South Carolina Department of Transportation (SCDOT). The CIP bridge is durable but has a long construction time while...

Controlled impact demonstration airframe bending bridges

NASA Technical Reports Server (NTRS)

Soltis, S. J.

1986-01-01

The calibration of the KRASH and DYCAST models for transport aircraft is discussed. The FAA uses computer analysis techniques to predict the response of controlled impact demonstration (CID) during impact. The moment bridges can provide a direct correlation between the predictive loads or moments that the models will predict and what was experienced during the actual impact. Another goal is to examine structural failure mechanisms and correlate with analytical predictions. The bending bridges did achieve their goals and objectives. The data traces do provide some insight with respect to airframe loads and structural response. They demonstrate quite clearly what's happening to the airframe. A direct quantification of metal airframe loads was measured by the moment bridges. The measured moments can be correlated with the KRASH and DYCAST computer models. The bending bridge data support airframe failure mechanisms analysis and provide residual airframe strength estimation. It did not appear as if any of the bending bridges on the airframe exceeded limit loads. (The observed airframe fracture was due to the fuselage encounter with the tomahawk which tore out the keel beam.) The airframe bridges can be used to estimate the impact conditions and those estimates are correlating with some of the other data measurements. Structural response, frequency and structural damping are readily measured by the moment bridges.

Dimension and bridging ligand effects on Mo-mediated catalytic transformation of dinitrogen to ammonia: Chain-like extended models of Nishibayashi’s catalyst

DOE PAGES

Sheng, Xiao -Lan; Batista, Enrique Ricardo; Duan, Yi -Xiang; ...

2016-11-01

Previous studies suggested that in Nishibayashi’s homogenous catalytic systems based on molybdenum (Mo) complexes, the bimetallic structure facilitated dinitrogen to ammonia conversion in comparison to the corresponding monometallic complexes, likely due to the through-bond interactions between the two Mo centers. However, more detailed model systems are necessary to support this bimetallic hypothesis, and to elucidate the multi-metallic effects on the catalytic mechanism. In this work, we computationally examined the effects of dimension as well as the types of bridging ligands on the catalytic activities of molybdenum-dinitrogen complexes by using a set of extended model systems based on Nishibayashi’s bimetallic structure.more » The polynuclear chains containing four ([Mo] 4) or more Mo centers were found to drastically enhance the catalytic performance by comparing with both the monometallic and bimetallic complexes. Carbide ([:C≡C:] 2–) was found to be a more effective bridging ligand than N 2 in terms of electronic charges dispersion between metal centers thereby facilitating reactions in the catalytic cycle. Furthermore, the mechanistic modelling suggests that in principle, more efficient catalytic system for N 2 to NH 3 transformation might be obtained by extending the polynuclear chain to a proper size in combination with an effective bridging ligand for charge dispersion.« less

Dimension and bridging ligand effects on Mo-mediated catalytic transformation of dinitrogen to ammonia: Chain-like extended models of Nishibayashi’s catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, Xiao -Lan; Batista, Enrique Ricardo; Duan, Yi -Xiang

Previous studies suggested that in Nishibayashi’s homogenous catalytic systems based on molybdenum (Mo) complexes, the bimetallic structure facilitated dinitrogen to ammonia conversion in comparison to the corresponding monometallic complexes, likely due to the through-bond interactions between the two Mo centers. However, more detailed model systems are necessary to support this bimetallic hypothesis, and to elucidate the multi-metallic effects on the catalytic mechanism. In this work, we computationally examined the effects of dimension as well as the types of bridging ligands on the catalytic activities of molybdenum-dinitrogen complexes by using a set of extended model systems based on Nishibayashi’s bimetallic structure.more » The polynuclear chains containing four ([Mo] 4) or more Mo centers were found to drastically enhance the catalytic performance by comparing with both the monometallic and bimetallic complexes. Carbide ([:C≡C:] 2–) was found to be a more effective bridging ligand than N 2 in terms of electronic charges dispersion between metal centers thereby facilitating reactions in the catalytic cycle. Furthermore, the mechanistic modelling suggests that in principle, more efficient catalytic system for N 2 to NH 3 transformation might be obtained by extending the polynuclear chain to a proper size in combination with an effective bridging ligand for charge dispersion.« less