WorldWideScience

Sample records for two-span bridge structure

  1. Research on Hybrid Seismic Response Control System for Motion Control of Two Span Bridge

    Science.gov (United States)

    Heo, G.; Kim, C.; Jeon, S.; Seo, S.; Jeon, J.

    2016-09-01

    In this paper, a hybrid seismic response control (HSRC) system was developed to control bridge motion caused by seismic load. It was aimed at optimum vibration control, composed of a rubber bearing of passive type and a MR-damper of semi-active type. The bridge model was built for experiment, a two-span bridge of 8.3 meters in length with the HSRC system put up on it. Then, inflicting El-centro seismic load on it, shaking table tests were carried out to confirm the system's validity. The experiments were conducted under the basic structure state (without an MR-damper applied) first, and then under the state with an MR-damper applied. It was also done under the basic structure state with a reinforced rubber bearing applied, then the passive on/off state of the HSRC system, and finally the semi-active state where the control algorithm was applied to the system. From the experiments, it was observed that collision rather increased when the MR-damper alone was applied, and also that the application of the HSRC system effectively prevented it from occurring. As a result, the HSRC system was proven to be effective in mitigating responses of the two-span bridge under seismic load.

  2. Experimental and Analytical Investigation of Deformations and Stress Distribution in Steel Bands of a Two-Span Stress-Ribbon Pedestrian Bridge

    Directory of Open Access Journals (Sweden)

    G. Sandovic

    2017-01-01

    Full Text Available The article is dedicated to the analysis of problems related to design of pedestrian bridges with flexible ribbon bands made of steel. The study is based on test results of a bridge model that has two spans (each with a length of five meters. A simplified analytical technique has been proposed for predicting vertical deformations of the bridge structure subjected to symmetrical or asymmetrical loading patterns. The technique also allows assessing the tension forces in the ribbons, which are very important for design of such structures. The analysis reveals the importance of the flexural rigidity of the ribbons that might cause significant redistribution of stresses within the steel bands.

  3. 两跨连续斜交梁桥振动台试验研究%Shaking table tests for a two-span continuous skew girder bridge

    Institute of Scientific and Technical Information of China (English)

    许永吉; 卓卫东; 孙颖

    2016-01-01

    The dynamic characteristics and three-dimensional seismic response of a two-span continuous skew girder bridge were analyzed,using parameters,such as,skew angle,shear span ratio,reinforcement ratio and axial compression ratio and so on.Taking a skewed girder bridge of Fujian as an engineering example,a 1 ∶5 scale two-span continuous skewed girder bridge model was designed for shaking table tests.Adopting shaking table tests and FE numerical analysis, the seismic responses and damage characteristics of the skewed girder bridge were studied.Results of shaking table tests showed that the structure's acceleration response and displacement response are guite different under different types of ground motion and at the same site or different types of ground motion and at different sites;under the same skew angle. the smaller the axial compression ratio,the larger the acceleration and displacement responses;when the axial compression ratio is the same,the smaller the skew angle,the larger the acceleration and displacement responses;a reasonable choice of skew angle has a great influence on the dynamic performance of skew bridges in the design of skew bridges.%选取了斜交角、配箍率和轴压比等设计参数,对两跨连续斜交梁桥进行结构动力特性分析和单向地震动输入下结构的地震反应分析。以福建省高速公路某座斜交梁桥为工程背景,设计制作了一座1/5缩尺两跨连续混凝土斜交梁桥试验模型,结合振动台模型试验和数值模拟分析,研究斜交梁桥地震响应及震害特点。振动台模型试验结果表明:不同场地类别的地震动及同一场地类别但不同的地震动作用下,结构的加速度响应、位移响应差别较大;在相同斜交角时,轴压比越小,加速度和位移响应越大;当轴压比相同时,斜交角越小,加速度和位移响应越大。从试验可知,在斜交桥设计中,合理选择斜交角对桥梁动力性能有很大的影响。

  4. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

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

  5. Bragg grating structural sensing system for bridge monitoring

    Science.gov (United States)

    Measures, Raymond M.; Alavie, A. Tino; Maaskant, Robert; Ohn, Myo M.; Karr, Shawn E.; Huang, Shang Yuan

    1994-09-01

    Corrosion of steel within bridges and other large concrete structures has become a serious problem and consequently there is growing interest in replacing the steel within such structures with carbon fiber based composite materials. The first highway bridge in the world to use carbon fiber composite prestressing tendons was constructed and opened to the public in the fall of 1993. This two span bridge was also unique in another respect, it is the first highway bridge in the world to have been built with a set of fiber optic Bragg grating sensors structurally integrated into several of its precast concrete deck support girders. A four-channel fiber laser sensor demodulation system that was rugged, compact and transportable was developed for this project. This demodulation system monitored the changes in the internal strain on all three types (steel and two types of carbon fiber composite) of prestressing tendons over several months. The same structurally integrated fiber optic sensing system has also been used to measure the change in the internal strain within the deck girders arising from both static and dynamic loading of the bridge with a large truck.

  6. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    In bridges the overall form must be chosen with due respect to the transmission of forces if efficient structures shall be created, The design must therefore be governed by experienced structural engineers - in some cases assisted by aesthetic advisers on specific issues. Some basic requirements...

  7. Excitation Methods for Bridge Structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

    1999-02-08

    This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

  8. 民用飞机两跨裂纹结构的剩余强度分析%Residual Strength Analysis about the Two-span Crack Structure of Civil Aircraft

    Institute of Scientific and Technical Information of China (English)

    许海生

    2012-01-01

    According the universal method, the residual strength of civil aircraft fuselage skin and wing skin can meet two-span crack. The designer need evaluates the residual strength of the skin in the condition of two-span crack in the primary-phrase design.%根据通用做法,民用飞机机身和机翼壁板在“两跨”长度裂纹存在情况下剩余强度能够满足要求,设计人员在飞机设计的初级阶段就要对两跨裂纹情况下壁板剩余强度进行评估.

  9. Bragg grating fiber optic sensing for bridges and other structures

    Science.gov (United States)

    Measures, Raymond M.; Alavie, A. Tino; Maaskant, Robert; Huang, Shang Yuan; LeBlanc, Michel

    1994-09-01

    We have demonstrated that fiber optic intracore Bragg grating sensors are able to measure the strain relief experienced over an extended period of time by both steel and carbon composite tendons within the concrete deck support girders of a recently constructed two span highway bridge. This is the first bridge in the world to test the prospects of using carbon fiber composite tendons to replace steel tendons. This unique set of measurements was accomplished with an array of 15 Bragg grating fiber optic sensors that were embedded within the precast concrete girders during their construction. We have also demonstrated that these same sensors can measure the change in the internal strain within the girders associated with both static and dynamic loading of the bridge with a truck. We are now studying the ability of Bragg grating fiber optic sensors to measure strong strain gradients and thereby provide a warning of debonding of any Bragg grating sensor from its host structure...one of the most important failure modes for any fiber optic strain sensor.

  10. Study on structural system of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Pei Minshan; Yuan Hong; Xu Liping; Zhu Bin

    2009-01-01

    Sutong Bridge, whose layout is [ (100 + 100 + 300) + 1 088 + ( 300 + 100 + 100) ] m, marks the largest span of cable-stayed bridges in the world. The complex natural condition at the bridge site and the strict requirements for resistance of wind and seismic action make it crucial to choose a favorable structural system to assure the function and safety of the bridge. The comparison among several optional structural systems for Sutong Bridge is illustrated. After detailed analysis is carried out for viscous damper and hydraulic buffer, super liquid viscous damper with additional displacement limitation is designed for the first application in bridge engineering. The parameters for the damper is analyzed and studied and the dampers are installed suecessfuUy after quality tests.

  11. VT Short Structures - Bridges and Culverts

    Data.gov (United States)

    Vermont Center for Geographic Information — Inspection data for structures (bridge and culvert) between 6 feet and 20 feet in length inspected on State road system. Stewards: Information Technology, Data...

  12. VT Long Structures - Bridges and Culverts

    Data.gov (United States)

    Vermont Center for Geographic Information — Inspection data for structures (bridge and culvert) greater than 20 feet in length inspected on both State and local road systems. Stewards: Information Technology,...

  13. VT Short Structures - Bridges and Culverts

    Data.gov (United States)

    Vermont Center for Geographic Information — Inspection data for structures (bridge and culvert) between 6 feet and 20 feet in length inspected on State road system. Stewards: Information Technology, Data...

  14. Fiber reinforced polymer composites for bridge structures

    Directory of Open Access Journals (Sweden)

    Alexandra CANTORIU

    2013-12-01

    Full Text Available Rapid advances in construction materials technology have led to the emergence of new materials with special properties, aiming at safety, economy and functionality of bridges structures. A class of structural materials which was originally developed many years ago, but recently caught the attention of engineers involved in the construction of bridges is fiber reinforced polymer composites. This paper provides an overview of fiber reinforced polymer composites used in bridge structures including types, properties, applications and future trends. The results of this study have revealed that this class of materials presents outstanding properties such as high specific strength, high fatigue and environmental resistance, lightweight, stiffness, magnetic transparency, highly cost-effective, and quick assembly, but in the same time high initial costs, lack of data on long-term field performance, low fire resistance. Fiber reinforced polymer composites were widely used in construction of different bridge structures such as: deck and tower, I-beams, tendons, cable stands and proved to be materials for future in this field.

  15. Structural characterization of thioether-bridged bacteriocins.

    Science.gov (United States)

    Lohans, Christopher T; Vederas, John C

    2014-01-01

    Bacteriocins are a group of ribosomally synthesized antimicrobial peptides produced by bacteria, some of which are extensively post-translationally modified. Some bacteriocins, namely the lantibiotics and sactibiotics, contain one or more thioether bridges. However, these modifications complicate the structural elucidation of these bacteriocins using conventional techniques. This review will discuss the techniques and strategies that have been applied to determine the primary structures of lantibiotics and sactibiotics. A major challenge is to identify the topology of thioether bridges in these peptides (i.e., which amino-acid residues are involved in which bridges). Edman degradation, NMR spectroscopy and tandem MS have all been commonly applied to characterize these bacteriocins, but can be incompatible with the post-translational modifications present. Chemical modifications to the modified residues, such as desulfurization and reduction, make the treated bacteriocins more compatible to analysis by these standard peptide analytical techniques. Despite their differences in structure, similar strategies have proved useful to study the structures of both lantibiotics and sactibiotics.

  16. Disulfide Bridges: Bringing Together Frustrated Structure in a Bioactive Peptide.

    Science.gov (United States)

    Zhang, Yi; Schulten, Klaus; Gruebele, Martin; Bansal, Paramjit S; Wilson, David; Daly, Norelle L

    2016-04-26

    Disulfide bridges are commonly found covalent bonds that are usually believed to maintain structural stability of proteins. Here, we investigate the influence of disulfide bridges on protein dynamics through molecular dynamics simulations on the cysteine-rich trypsin inhibitor MCoTI-II with three disulfide bridges. Correlation analysis of the reduced cyclic peptide shows that two of the three disulfide distances (Cys(11)-Cys(23) and Cys(17)-Cys(29)) are anticorrelated within ∼1 μs of bridge formation or dissolution: when the peptide is in nativelike structures and one of the distances shortens to allow bond formation, the other tends to lengthen. Simulations over longer timescales, when the denatured state is less structured, do not show the anticorrelation. We propose that the native state contains structural elements that frustrate one another's folding, and that the two bridges are critical for snapping the frustrated native structure into place. In contrast, the Cys(4)-Cys(21) bridge is predicted to form together with either of the other two bridges. Indeed, experimental chromatography and nuclear magnetic resonance data show that an engineered peptide with the Cys(4)-Cys(21) bridge deleted can still fold into its near-native structure even in its noncyclic form, confirming the lesser role of the Cys(4)-Cys(21) bridge. The results highlight the importance of disulfide bridges in a small bioactive peptide to bring together frustrated structure in addition to maintaining protein structural stability.

  17. reliability analysis of a two span floor designed according to ...

    African Journals Online (AJOL)

    user

    The Structural analysis and design of the timber floor system was carried out using deterministic approach ... The cell structure of hardwoods is more complex than ..... [12] BS EN -1-1: Eurocode 5: Design of Timber Structures, Part. 1-1.

  18. Bridges analysis, design, structural health monitoring, and rehabilitation

    CERN Document Server

    Bakht, Baidar

    2015-01-01

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

  19. Structural health monitoring of bridges in the State of Connecticut

    Institute of Scientific and Technical Information of China (English)

    Chengyin Liu; Joshua Olund; Alan Cardini; Paul D'Attilio; Erie Feldblum; John DeWolf

    2008-01-01

    A joint effort between the Connecticut Department of Transportation and the University of Connecticut has been underway for more than 20 years to utilize various structural monitoring approaches to assess different bridges in Connecticut.This has been done to determine the performance of existing bridges,refine techniques needed to evaluate different bridge components,and develop approaches that can be used to provide a continuous status of a bridge's structural integrity,This paper briefly introduces the background of these studies,with emphasis on recent research and the development of structural health monitoring concepts.This paper presents the results from three different bridge types:a post-tensioned curved concrete box girder bridge,a curved steel box-girder bridge,and a steel multi-girder bridge.The structural health monitoring approaches to be discussed have been successfully tested using field data collected during multi-year monitoring periods,and are based on vibrations,rotations and strains.The goal has been to develop cost-effective strategies to provide critical information needed to manage the State of Connecticut's bridge infrastructure.

  20. Structural safety monitoring for Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    黄方林; 何旭辉; 陈政清; 曾储惠

    2004-01-01

    In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.

  1. Methods and tools for diagnosing bridge structures

    Directory of Open Access Journals (Sweden)

    С.Ф. Філоненко

    2008-03-01

    Full Text Available  In the paper is reviewed the methods and means, which used at technical diagnostic of bridge designs. The general approaches to technical diagnostic, the main methods, primary converters and hardwares, which used on static and dynamic tests of bridge designs are reviewed.

  2. Multidisciplinary health monitoring of a steel bridge deck structure

    NARCIS (Netherlands)

    Pahlavan, P.L.; Pijpers, R.J.M.; Paulissen, J.H.; Hakkesteegt, H.C.; Jansen, T.H.

    2013-01-01

    Fatigue cracks in orthotropic bridge decks are an important cause for the necessary renovation of existing bridges. Parallel utilization of various technologies based on different physical sensing principles can potentially maximize the efficiency of structural health monitoring (SHM) systems for th

  3. IMPLEMENTATION OF DIAGNOSIS AND REPAIR OF BRIDGE STRUCTURES

    Directory of Open Access Journals (Sweden)

    Yushkov Vladimir Sergeevich

    2016-06-01

    Full Text Available Insufficiency and delays of maintenance of the technical state of bridges is greatly related to work labour input, absence of adequate mechanical means and automation of the process of inspection of structures. The authors considered domestic and foreign Machinery which repair bridge structures and are used to conduct surveys, tests and special repairs on different levels, both above and below the vehicle position. The design of a machine with the main operational characteristics is presented. The defects detected during the inspection of bridges are enumerated. In the conditions of deterioration of the bridges of different structures and responding the requirements to reduce the risk level of engineering structures’ operation there is a demand in renewing the population of machines for investigation of the technical condition of automobile bridge, because of special vehicles deterioration, there is no staff of specialists who are able to solve the problems of maintenance and increasing the reliability of bridge structures to the required extend. Also the main principles of control and inspection of bridge structures include the requirements to technical equipment for measurements and testing equipment.

  4. PS buildings : reinforced concrete structure for shielding "bridge" pillar

    CERN Document Server

    CERN PhotoLab

    1956-01-01

    The PS ring traverses the region between the experimental halls South and North (buildings Nos 150 and 151) under massive bridge-shaped concrete beams. This pillar stands at the S-W end of the structure.

  5. An active vibration control method of bridge structures by the ...

    African Journals Online (AJOL)

    An active vibration control method of bridge structures by the linearization of ... zones due to economic requirements, and with occurrence of seismic events in ... linearization proportionality coefficients are constantly modified to optimal values.

  6. Composite timber-concrete road bridge structure

    Directory of Open Access Journals (Sweden)

    Stojić Dragoslav

    2007-01-01

    Full Text Available This work presents preliminary design of the road bridge made of laminated timber. The supporting system of the main bearing elements is made of the laminated timber in the system of arch with three joints; the bridge slab is designed as continuous slab, made of nine equal fields; each pair is made as composite timber-concrete beam, where the road slab is made of concrete and the needle pieces are made of timber. Fundament is based on HW piles. All the elements are designed to Eurocode.

  7. Information-theoretical noninvasive damage detection in bridge structures

    Science.gov (United States)

    Sudu Ambegedara, Amila; Sun, Jie; Janoyan, Kerop; Bollt, Erik

    2016-11-01

    Damage detection of mechanical structures such as bridges is an important research problem in civil engineering. Using spatially distributed sensor time series data collected from a recent experiment on a local bridge in Upper State New York, we study noninvasive damage detection using information-theoretical methods. Several findings are in order. First, the time series data, which represent accelerations measured at the sensors, more closely follow Laplace distribution than normal distribution, allowing us to develop parameter estimators for various information-theoretic measures such as entropy and mutual information. Second, as damage is introduced by the removal of bolts of the first diaphragm connection, the interaction between spatially nearby sensors as measured by mutual information becomes weaker, suggesting that the bridge is "loosened." Finally, using a proposed optimal mutual information interaction procedure to prune away indirect interactions, we found that the primary direction of interaction or influence aligns with the traffic direction on the bridge even after damaging the bridge.

  8. Use of UHPC in Bridge Structures: Material Modeling and Design

    Directory of Open Access Journals (Sweden)

    Oguz Gunes

    2012-01-01

    Full Text Available Ultra-high-performance concrete (UHPC is a promising new class of concrete material that is likely to make a significant contribution to addressing the challenges associated with the load capacity, durability, sustainability, economy, and environmental impact of concrete bridge infrastructures. This paper focuses on the material modeling of UHPC and design of bridge girders made of UHPC. A two-phase model used for modeling the behavior of UHPC was briefly discussed, and the model was implemented in a preliminary design case study. Based on the implemented design and the reported use of UHPC in bridge applications, the advantages, limitations, and future prospects of UHPC bridges were discussed, highlighting the need for innovative research and design to make optimum use of the favorable properties of the material in bridge structures.

  9. Mathematical models for suspension bridges nonlinear structural instability

    CERN Document Server

    Gazzola, Filippo

    2015-01-01

    This work provides a detailed and up-to-the-minute survey of the various stability problems that can affect suspension bridges. In order to deduce some experimental data and rules on the behavior of suspension bridges, a number of historical events are first described, in the course of which several questions concerning their stability naturally arise. The book then surveys conventional mathematical models for suspension bridges and suggests new nonlinear alternatives, which can potentially supply answers to some stability questions. New explanations are also provided, based on the nonlinear structural behavior of bridges. All the models and responses presented in the book employ the theory of differential equations and dynamical systems in the broader sense, demonstrating that methods from nonlinear analysis can allow us to determine the thresholds of instability.

  10. Damage assessment of a two-span RC slab using wavelet analysis

    Science.gov (United States)

    Zhu, X. Q.; Hao, H.

    2007-04-01

    A two-span RC slab that measures 6400mm×800mm×100mm with 3000mm spans and 200mm overhang on each end was tested to failure in the laboratory. UB sections were used as supports. The slab was designed according to the moment redistribution method with 11 N6 bars at 75mm centres for both positive and negative reinforcement. The slab was incrementally loaded at the middle of each span to different load levels to create crack damage using four-point loading. Twelve loading stages were performed with increasing maximum load level. Two load cells are used to record the static loads on left and right spans. The crack locations and lengths were monitored in addition to the displacement measurements. Four displacement transducers are located at two sides of the middle of each span to measure the deflection under the static load. Three sets of accelerometers with nine of them in each set are evenly distributed along the slab to measure the dynamic responses. The measured responses from the RC slab in different cracked damage states are analyzed using the wavelet transform (WT). The damping ratios and instantaneous frequency are extracted. The results show that the damping ratio and instantaneous frequency changes could be two good indicators of damage in the reinforced concrete structure.

  11. Preliminary study to facilitate smart structure systems in bridge girders

    Science.gov (United States)

    Kirkpatrick, Thomas C.; Peterson, Danford O.; Rossi, Peter J.; Ray, Laura R.; Livingston, Richard A.

    1999-05-01

    Sensors are currently available and used to monitor structural performance and loads incurred by bridges already in service. However, there has been limited research concerning the stresses that steel bridge girders endure during transport from the manufacturer to the job site and during the installation process. This paper reports the measured stresses on steel bridge girders during transportation from Lancaster, PA to Hanover, NH and during construction of the Ledyard Bridge on the New Hampshire - Vermont border. Two different monitoring system were developed for this data acquisition in a mobile environment. The first, a fiber optic strain monitoring system, utilizing Bragg grating technology. The second utilized an electrical- resistive foil strain gage network, in conjunction with wireless telemetry equipment. Together, these two systems formed a smart structure system for monitoring bridge girders while confirming the accuracy of data gathered through redundancy. Result conclusively demonstrated for the first time, that stresses in beams during transportation are significant and approach the factor of safety margin in girder design.

  12. Structural reliability of existing city bridges

    NARCIS (Netherlands)

    Hellebrandt, L.; Steenbergen, R.; Vrouwenvelder, T.; Blom, K.

    2015-01-01

    Full probabilistic reliability analysis may be valuable for assessing existing structures. Measures for increasing the safety level are quite costly for existing structures and may be unnecessary when such a decision is grounded on a conservative analysis for determining the structural reliability.

  13. Probabilistic inspection and maintenance for concrete bridge structures

    NARCIS (Netherlands)

    Li, Y.; Vrouwenvelder, A.C.W.M.

    2002-01-01

    Due to a variety of physical and chemical processes, concrete bridges as well as other civil engineering structures deteriorate and may reach, after some time, a minimum acceptable level of performance. At that point in time maintenance (including inspection, repair and replacement) has to be carrie

  14. Probabilistic model for bridge structural evaluation using nondestructive inspection data

    Science.gov (United States)

    Carrion, Francisco; Lopez, Jose Alfredo; Balankin, Alexander

    2005-05-01

    A bridge management system developed for the Mexican toll highway network applies a probabilistic-reliability model to estimate load capacity and structural residual life. Basic inputs for the system are the global inspection data (visual inspections and vibration testing), and the information from the environment conditions (weather, traffic, loads, earthquakes); although, the model takes account for additional non-destructive testing or permanent monitoring data. Main outputs are the periodic maintenance, rehabilitation and replacement program, and the updated inspection program. Both programs are custom-made to available funds and scheduled according to a priority assignation criterion. The probabilistic model, tailored to typical bridges, accounts for the size, age, material and structure type. Special bridges in size or type may be included, while in these cases finite element deterministic models are also possible. Key feature is that structural qualification is given in terms of the probability of failure, calculated considering fundamental degradation mechanisms and from actual direct observations and measurements, such as crack distribution and size, materials properties, bridge dimensions, load deflections, and parameters for corrosion evaluation. Vibration measurements are basically used to infer structural resistance and to monitor long term degradation.

  15. Cathodic protection of RC structures - Far more than bridge decks

    NARCIS (Netherlands)

    Nerland, O.C.; Polder, R.B.

    2002-01-01

    When the first trials with Cathodic Protection (CP) on reinforced concrete (RC) structures were carried out nearly 30 years ago the main aim was treating steel in bridge decks, suffering from chloride induced corrosion. Various types of anode systems (conductive asphalt, conductive mortars, carbon f

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

    Science.gov (United States)

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

    2017-06-01

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

  17. Organelle Structures: Bridging Strategy and Technological Processes

    Institute of Scientific and Technical Information of China (English)

    Rob; Dekkers

    2002-01-01

    The shifting requirements as imposed on operations ma nagement require adjusting and tailoring the organisational structure to meet ma rket demands. However, translating these requirements directly into hierarchical structure will not ensure the integration of processes across organisational un its and guarantee desirable performance. Therefore, management and management li terature wonders: · How should we connect processes to the external environment within a strategi c framework · Which organisationa...

  18. Wake-up transceivers for structural health monitoring of bridges

    Science.gov (United States)

    Kumberg, T.; Kokert, J.; Younesi, V.; Koenig, S.; Reindl, L. M.

    2016-04-01

    In this article we present a wireless sensor network to monitor the structural health of a large-scale highway bridge in Germany. The wireless sensor network consists of several sensor nodes that use wake-up receivers to realize latency free and low-power communication. The sensor nodes are either equipped with very accurate tilt sensor developed by Northrop Grumman LITEF GmbH or with a Novatel OEM615 GNSS receiver. Relay nodes are required to forward measurement data to a base station located on the bridge. The base station is a gateway that transmits the local measurement data to a remote server where it can be further analyzed and processed. Further on, we present an energy harvesting system to supply the energy demanding GNSS sensor nodes to realize long term monitoring.

  19. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

    Science.gov (United States)

    Wu, Lai-Yi

    2015-01-01

    Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature. PMID:26451387

  20. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure.

    Science.gov (United States)

    Ding, You-Liang; Wang, Gao-Xin; Sun, Peng; Wu, Lai-Yi; Yue, Qing

    2015-01-01

    Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  1. Structural Health Monitoring of Bridges with Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Francisco Navarro-Henríquez

    2014-11-01

    Systems with fiber optic sensors FBG (Fiber Bragg Grating are consolidated in the Structural Health Monitoring (SMH of bridges, Nondestructive Testing (NDT static and dynamic measurements of deformation, displacement, deflection, temperature and vibration. This article provides a brief introduction to the technology and the fundamentals of fiber optic sensors, also present comparative advantages over its traditional counterpart is presented. Their characteristics are described and measurement graphics are presented as an application example of the FBG sensors. Finally, some key aspects to consider for proper use in the field are mentioned.

  2. Monitoring Structural Health of Different Types of Bridges Using Advanced Multi-Temporal InSAR

    Science.gov (United States)

    Qin, Xiaoqiong; Liao, Mingsheng; Yang, Mengshi; Zhang, Lu; Balz, Timo

    2016-08-01

    Since the bridges paly a significance role in national economic development and transportation safety, the structure health and safety of bridges aroused a lot of concern in society and become a hotspot research in earth observation and civil engineering. However, the materials degradation and environmental stresses increase may destroy the structure of bridges and pose significant risks to public safety and quality of life. This highlighted the importance of developing effective structure health monitoring strategies to reflect the current status of bridges and identify structural problems. In this work, an advanced multi-temporal InSAR technique is introduced into deformation monitoring of bridges. We focus on analysis the distribution of PSs, distinction of stable and unstable parts and recognition temporal-spatial deformation characteristics at the scale of single bridge through the examples of different types of bridges in Tianjin and Shanghai.

  3. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

    Directory of Open Access Journals (Sweden)

    You-Liang Ding

    2015-01-01

    Full Text Available Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge’s abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  4. Risk based bridge data collection and asset management and the role of structural health monitoring

    Science.gov (United States)

    Omenzetter, Piotr; Bush, Simon; Henning, Theunis; McCarten, Peter

    2011-04-01

    Bridges are critical to the operation and functionality of the whole road networks. It is therefore essential that specific data is collected regarding bridge asset condition and performance, as this allows proactive management of the assets and associated risks and more accurate short and long term financial planning. This paper proposes and discusses a strategy for collection of data on bridge condition and performance. Recognizing that risk management is the primary driver of asset management, the proposed strategy prioritizes bridges for levels of data collection including core, intermediate and advanced. Individual bridges are seen as parts of wider networks and bridge risk and criticality assessment emphasizes bridge failure or underperformance risk in the network context. The paper demonstrates how more reliable and detailed data can assist in managing network and bridge risks and provides a rationale for application of higher data collection levels for bridges characterized by higher risk and criticality. As the bridge risk and/or criticality increases planned and proactive integration of structural health monitoring (SHM) data into asset management is outlined. An example of bridge prioritization for data collection using several bridges taken from a national highway network is provided using an existing risk and criticality scoring methodology. The paper concludes with a discussion on the role of SHM in data collection for bridge asset management and where SHM can make the largest impacts.

  5. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  6. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... the averaged spectral densities(ASD). From the ASD the eigenfrequencies of the structure can be identified. This information can be used in the main analysis, where alle modal parameters are extracted from the spectral densities. Due to long cabling and low response levels (small ambient loads) the response...

  7. Ambient Modal Testing of the Vestvej Bridge using Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune; Rytter, A.

    1998-01-01

    This paper presents an ambient vibration study of the Vestvej Bridge. The bridge is a typically Danish two-span concrete bridge which crosses a highway. The purpose of the study is to perform a pre-investigation of the dynamic behavior to obtain information for the design of a demonstration project...... concerning application of vibration based inspection of bridges. The data analysis process of ambient vribration testing of bridges has traditionally been based on auto and cross spectral densities estimated using an FFT algorithm. In the pre-analysis state the spectral densities are all averaged to obtain...... the averaged spectral densities(ASD). From the ASD the eigenfrequencies of the structure can be identified. This information can be used in the main analysis, where alle modal parameters are extracted from the spectral densities. Due to long cabling and low response levels (small ambient loads) the response...

  8. Dispersion management for nonlinearity mitigation in two-span 28 GBaud QPSK phase-sensitive amplifier links.

    Science.gov (United States)

    Astra, Egon; Olsson, Samuel L I; Eliasson, Henrik; Andrekson, Peter A

    2017-06-12

    We present an investigation of dispersion map optimization for two-span single-channel 28 GBaud QPSK transmission systems with phase-sensitive amplifiers (PSAs). In experiments, when the PSA link is operated in a highly nonlinear regime, a 1.4 dB error vector magnitude (EVM) improvement is achieved compared to a one-span optimized dispersion map link due to improved nonlinearity mitigation. The two-span optimized dispersion map of a PSA link differs from the optimized dispersion map of a dispersion managed phase-insensitive amplifier (PIA) link. Simulations show that the performance of the two-span dispersion map optimized PSA link does not improve by residual dispersion optimization. Further, by using the two-span optimized dispersion maps repeatedly in a long-haul PSA link instead of one-span optimized maps, the maximum transmission reach can be improved 1.5 times.

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

    Science.gov (United States)

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

    2014-01-01

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

  10. Thermodynamic substantiation of water-bridged collagen structure.

    Science.gov (United States)

    Burjanadze, T V

    1992-08-01

    A solution of the problem of topology of a hydrogen bond net in a triple helix of collagen is suggested on the basis of an analysis of thermodynamic data on denaturation of phylogenetically different collagen [T. V. Burjanadze (1982), Vol. 21, pp. 1489-1501; T. V. Burjanadze, E. I. Tiktopulo, and P. L. Privalov (1987), Dokl. Akad. Nauk. USSR, Vol. 293, pp. 720-724] as well as on the earlier evaluation of the energy of the OH group of the 4-hydroxyproline bond [A. R. Ward and P. Mason (1973), Journal of Molecular Biology, Vol. 29, pp. 431-435]. It is shown that only the water-bridged collagen structure [G. N. Ramachandran and R. Chandrasekharan (1968), Biopolymers, Vol. 6, pp. 1649-1661; G. N. Ramachandran, M. Bansal, and R. S. Bhatnagar (1973), Biochimica Biophysica Acta, Vol. 322, pp. 166-171; M. Bansal, C. Ramakrishnan, and G. N. Ramachandran (1975), Proceedings of the Indian Academy of Sciences, Vol. 82, pp. 152-164] can explain both the change of thermostability upon proline hydroxylation [J. Rosenbloom, M. Harsch, and S. Jimenez (1973), Archives of Biochemistry and Biophysics, Vol. 158, pp. 478-484] and its phylogenetic change [T. V. Burjanadze (1982)].

  11. Structure of a model salt bridge in solution investigated with 2D-IR spectroscopy

    CERN Document Server

    Huerta-Viga, Adriana; Amirjalayer, Saeed; Woutersen, Sander

    2013-01-01

    Salt bridges are known to be important for the stability of protein conformation, but up to now it has been difficult to study their geometry in solution. Here we characterize the spatial structure of a model salt bridge between guanidinium (Gdm+) and acetate (Ac-) using two-dimensional vibrational (2D-IR) spectroscopy. We find that as a result of salt bridging the infrared response of Gdm+ and Ac- change significantly, and in the 2D-IR spectrum, salt bridging of the molecules appears as cross peaks. From the 2D-IR spectrum we determine the relative orientation of the transition-dipole moments of the vibrational modes involved in the salt bridge, as well as the coupling between them. In this manner we reconstruct the geometry of the solvated salt bridge.

  12. Town Bridge and Culvert Inventories - Export-Structures App Tool

    Data.gov (United States)

    Vermont Center for Geographic Information — VTCULVERTS.org app tool for exporting town bridge and culvert inventories that are currently collected by the RPCs (Regional Planning Commissions), towns, and their...

  13. Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

    OpenAIRE

    Flaga Kazimierz; Furtak Kazimierz

    2015-01-01

    Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life).

  14. THE INFLUENCE OF SOME DEFECTS OF BRIDGE STRUCTURES ON THEIR OPERATIONAL DURABILITY

    Directory of Open Access Journals (Sweden)

    А. V. Bilchenko

    2007-10-01

    Full Text Available The drawbacks of organizational and technical means of bridge construction and operation in Ukraine are presented. A problem of the primary impact of hydroisolation and water-disposal on occurrence of defects in loadcarrying bridge structures is raised.

  15. AHP-VIKOR Bridge Structural System Selection in Urban Areas Tehran: Interchanges Case Study

    OpenAIRE

    Ali Akbar Ramezanianpour; Seyyed Alireza Tabatabaei; Mahyar Pourlak; Majid Abareshi

    2016-01-01

    The selection of “Structural system” is one of the most important factors in any bridge and infrastructure design. Designers perform the structural calculations for the project determines the priorities as well as design and performance criteria. Further analysis of the structural selection problem and the identification of the bridge desirable capabilities, triggered the consideration of analytic hierarchy process (AHP) as a possible basis for the decision making. The methodology uses the VI...

  16. Evaluation of Structural Behavior of Externally Prestressed Segmented Bridge with Shear Key under Torsion

    Directory of Open Access Journals (Sweden)

    M. A. Algorafi

    2011-07-01

    Full Text Available Externally Prestressed Segmented (EPS concrete beams are generally used in the construction of bridge structures. External Prestressed technique uses tendons that are placed completely outside the concrete section and attached to the concrete at anchorages and deviators only. Segmented bridge is a bridge built in short sections. Segmented bridge applies smart technique that is a part of an engineering management. EPS bridges are affected by combined stresses i.e., bending, shear, normal, and torsion stresses especially at the segments interface joints. Previous studies on EPS bridges did not include the effect of torsion in the load carrying capacity and other structural behavior. This paper presents an experimental investigation of the structural behavior of EPS bridged under combined bending, shear, normal, and torsion stresses. The aim of this paper is to improve the existing equation to include the effect of torsion in estimating the failure load of EPS bridge. A parametric study was carried out to investigate the effect of different external tendon layouts and different levels of torsion.

  17. Dynamic test and finite element model updating of bridge structures based on ambient vibration

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The dynamic characteristics of bridge structures are the basis of structural dynamic response and seismic analysis,and are also an important target of health condition monitoring.In this paper,a three-dimensional finite-element model is first established for a highway bridge over a railroad on No.312 National Highway.Based on design drawings,the dynamic characteristics of the bridge are studied using finite element analysis and ambient vibration measurements.Thus,a set of data is selected based on sensitivity analysis and optimization theory;the finite element model of the bridge is updated.The numerical and experimental results show that the updated method is more simple and effective,the updated finite element model can reflect the dynamic characteristics of the bridge better,and it can be used to predict the dynamic response under complex external forces.It is also helpful for further damage identification and health condition monitoring.

  18. Structural health monitoring of long-span suspension bridges using wavelet packet analysis

    Institute of Scientific and Technical Information of China (English)

    Ding Youliang; Li Aiqun

    2007-01-01

    During the service life of civil engineering structures such as long-span bridges, local damage at key positions may continually accumulate, and may finally result in their sudden failure. One core issue of global vibration-based health monitoring methods is to seek some damage indices that are sensitive to structural damage. This paper proposes an online structural health monitoring method for long-span suspension bridges using wavelet packet transform (WPT). The WPTbased method is based on the energy variations of structural ambient vibration responses decomposed using wavelet packet analysis. The main feature of this method is that the proposed wavelet packet energy spectrum (WPES) has the ability to detect structural damage from ambient vibration tests of a long-span suspension bridge. As an example application, the WPES-based health monitoring system is used on the Runyang Suspension Bridge under daily environmental conditions. The analysis reveals that changes in environmental temperature have a long-term influence on the WPES, while the effect of traffic loadings on the measured WPES of the bridge presents instantaneous changes because of the nonstationary properties of the loadings. The condition indication indices VD reflect the influences of environmental temperature on the dynamic properties of the Runyang Suspension Bridge. The field tests demonstrate that the proposed WPES-based condition indication index VD is a good candidate index for health monitoring of long-span suspension bridges under ambient excitations.

  19. Structural health monitoring of long-span suspension bridges using wavelet packet analysis

    Science.gov (United States)

    Ding, Youliang; Li, Aiqun

    2007-09-01

    During the service life of civil engineering structures such as long-span bridges, local damage at key positions may continually accumulate, and may finally result in their sudden failure. One core issue of global vibration-based health monitoring methods is to seek some damage indices that are sensitive to structural damage. This paper proposes an online structural health monitoring method for long-span suspension bridges using wavelet packet transform (WPT). The WPT-based method is based on the energy variations of structural ambient vibration responses decomposed using wavelet packet analysis. The main feature of this method is that the proposed wavelet packet energy spectrum (WPES) has the ability to detect structural damage from ambient vibration tests of a long-span suspension bridge. As an example application, the WPES-based health monitoring system is used on the Runyang Suspension Bridge under daily environmental conditions. The analysis reveals that changes in environmental temperature have a long-term influence on the WPES, while the effect of traffic loadings on the measured WPES of the bridge presents instantaneous changes because of the nonstationary properties of the loadings. The condition indication indices V D reflect the influences of environmental temperature on the dynamic properties of the Runyang Suspension Bridge. The field tests demonstrate that the proposed WPES-based condition indication index V D is a good candidate index for health monitoring of long-span suspension bridges under ambient excitations.

  20. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    Directory of Open Access Journals (Sweden)

    Paolo Lonetti

    2016-10-01

    Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes

  1. Three-dimensional structure of a sunspot light bridge

    CERN Document Server

    Felipe, T; Khomenko, E; Kuckein, C; Ramos, A Asensio; Balthasar, H; Berkefeld, T; Denker, C; Feller, A; Franz, M; Hofmann, A; Kiess, C; Lagg, A; Nicklas, H; Suárez, D Orozco; Yabar, A Pastor; Rezaei, R; Schlichenmaier, R; Schmidt, D; Schmidt, W; Sigwarth, M; Sobotka, M; Solanki, S K; Soltau, D; Staude, J; Strassmeier, K G; Volkmer, R; von der Lühe, O; Waldmann, T

    2016-01-01

    Active regions are the most prominent manifestations of solar magnetic fields; their generation and dissipation are fundamental problems in solar physics. Light bridges are commonly present during sunspot decay, but a comprehensive picture of their role in the removal of photospheric magnetic field is still missing. We study the three dimensional configuration of a sunspot and in particular its light bridge during one of the last stages of its decay. We present the magnetic and thermodynamical stratification inferred from full Stokes inversions of the photospheric Si I 10827 \\AA\\ and Ca I 10839 \\AA\\ lines obtained with the GREGOR Infrared Spectrograph of the GREGOR telescope at Observatorio del Teide, Tenerife, Spain. The analysis is complemented by a study of continuum images covering the disk passage of the active region, which are provided by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. The sunspot shows a light bridge with penumbral continuum intensity that separates the c...

  2. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    OpenAIRE

    Paolo Lonetti; Arturo Pascuzzo

    2016-01-01

    A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displace...

  3. Combined Differential and Static Pressure Sensor based on a Double-Bridged Structure

    DEFF Research Database (Denmark)

    Pedersen, Casper; Jespersen, S.T.; Krog, J.P.

    2005-01-01

    . Output from the two bridges depends linearly on both differential and absolute (relative to atmospheric pressure) media pressure. Furthermore, the sensor stress distributions involved are studied by three-dimensional finite-element (FE) stress analysis. Furthermore, the FE analysis evaluates current......A combined differential and static silicon microelectromechanical system pressure sensor based on a double piezoresistive Wheatstone bridge structure is presented. The developed sensor has a conventional (inner) bridge on a micromachined diaphragm and a secondary (outer) bridge on the chip...... substrate. A novel approach is demonstrated with a combined measurement of outputs from the two bridges, which results in a combined deduction of both differential and static media pressure. Also following this new approach, a significant improvement in differential pressure sensor accuracy is achieved...

  4. Effect of abutment modeling on the seismic response of bridge structures

    Institute of Scientific and Technical Information of China (English)

    Ady Aviram; Kevin R.Mackie; Bozidar Stojadinovic

    2008-01-01

    Abutment behavior significantly influences the seismic response of certain bridge structures.Specifically in the case of short bridges with relatively stiff superstructures typical of highway overpasses,embankment mobilization and inelastic behavior of the soil material under high shear deformation levels dominate the response of the bridge and its column bents.This paper investigates the sensitivity of bridge seismic response with respect to three different abutment modeling approaches.The abutment modeling approaches are based on three increasing levels of complexity that attempt to capture the critical components and modes of abutment response without the need to generate continuum models of the embankment,approach,and abutment foundations.Six existing reinforced concrete bridge structures,typical of Ordinary Bridges in California,are selected for the analysis.Nonlinear models of the bridges are developed in OpenSees.Three abutment model types of increasing complexity are developed for each bridge,denoted as roller,simplified,and spring abutments.The roller model contains only single-point constraints.The spring model contains discrete representations of backfill,bearing pad,shear key,and back wall behavior.The simplified model is a compromise between the efficient roller model and the comprehensive spring model.Modal,pushover,and nonlinear dynamic time history analyses are conducted for the six bridges using the three abutment models for each bridge.Comparisons of the analysis results show major differences in mode shapes and periods,ultimate base shear strength,as well as peak displacements of the column top obtained due to dynamic excitation.The adequacy of the three abutment models used in the study to realistically represent all major resistance mechanisms and components of the abutments,including an accurate estimation of their mass,stiffness,and nonlinear hysteretic behavior,is evaluated.Recommendations for abutment modeling are made.

  5. Structural Health Monitoring Using Wireless Technologies: An Ambient Vibration Test on the Adolphe Bridge, Luxembourg City

    Directory of Open Access Journals (Sweden)

    Adrien Oth

    2012-01-01

    Full Text Available Major threats to bridges primarily consist of the aging of the structural elements, earthquake-induced shaking and standing waves generated by windstorms. The necessity of information on the state of health of structures in real-time, allowing for timely warnings in the case of damaging events, requires structural health monitoring (SHM systems that allow the risks of these threats to be mitigated. Here we present the results of a short-duration experiment carried out with low-cost wireless instruments for monitoring the vibration characteristics and dynamic properties of a strategic civil infrastructure, the Adolphe Bridge in Luxembourg City. The Adolphe Bridge is a masonry arch construction dating from 1903 and will undergo major renovation works in the upcoming years. Our experiment shows that a network of these wireless sensing units is well suited to monitor the vibration characteristics of such a historical arch bridge and hence represents a low-cost and efficient solution for SHM.

  6. AHP-VIKOR Bridge Structural System Selection in Urban Areas Tehran: Interchanges Case Study

    Directory of Open Access Journals (Sweden)

    Ali Akbar Ramezanianpour

    2016-10-01

    Full Text Available The selection of “Structural system” is one of the most important factors in any bridge and infrastructure design. Designers perform the structural calculations for the project determines the priorities as well as design and performance criteria. Further analysis of the structural selection problem and the identification of the bridge desirable capabilities, triggered the consideration of analytic hierarchy process (AHP as a possible basis for the decision making. The methodology uses the VIKOR to evaluate the alternatives according to the decision criteria and determine the solution. The methodology was developed by a group of bridge designers involved in design and management of urban infrastructure projects and demonstrated using a Steel Girder bridge in an urban area as an optimum alternative.

  7. Structural Assessment of Externally Strengthened Bridge Deck Panels

    Science.gov (United States)

    Sim, Jongsung; Oh, Hongseob; Meyer, Christian

    2006-03-01

    Deteriorated concrete bridge decks are strengthened with external bonding technique using either steel plate or various FRPs to enhance the decreased load carrying capacity and serviceability. But the failure characteristics of bridge decks strengthened with various materials can be changed according to mechanical properties of strengthening materials or strengthening scheme as well as the strengthening amount. In this paper, strengthening effect of deck strengthened with carbon fiber sheets, glass fiber sheets or steel plates is compared. And the theoretical load carrying capacity are evaluated using yield line theory and punching shear model properly modified for the strengthened RC member. The panels strengthened with sheet type FRP materials failed more often in a ductile mode, indicating that the failure developed after the rebar yielded.

  8. A structural bridge between alternant and non-alternant hydrocarbons

    Directory of Open Access Journals (Sweden)

    Richard Francis Langler

    2001-06-01

    Full Text Available A simple set of trimethylene-substituted even, fully-pi-bonded, non-alternant monocycles is shown to have several key features in common with acyclic, even alternant polyenes at the Hückel level. These non-alternant molecules provide a bridge between alternant and non-alternant hydrocarbons. This topic might serve as a useful addition to Hückel theory courses targeted at senior undergraduate students.

  9. Syntheses and Structures of Binaphthyl-bridged Schiff Bases

    Institute of Scientific and Technical Information of China (English)

    WANG Bin; LI Min-xiong; XU Shan-sheng; SONG Hai-bin; WANG Bai-quan

    2008-01-01

    The reaction ofdinaphthofuran with lithium in anhydrous diethyl ether led to a solution of the corresponding C,O-dilithiated intermediate which,upon treatment with DMF at -78 ℃,afforded,after hydrolysis,2'-hydroxy-1,1'-binaphthyl-2-carbaldehyde in a good yield.Then binaphthyl-bridged Schiff bases were prepared by the condensation of 2'-hydroxy-1,1'-binaphthyl-2-carbaldehyde with the corresponding aromatic amines.

  10. Fatigue damage reliability analysis for Nanjing Yangtze river bridge using structural health monitoring data

    Institute of Scientific and Technical Information of China (English)

    HE Xu-hui; CHEN Zheng-qing; YU Zhi-wu; HUANG Fang-lin

    2006-01-01

    To evaluate the fatigue damage reliability of critical members of the Nanjing Yangtze river bridge, according to the stress-number curve and Miner's rule, the corresponding expressions for calculating the structural fatigue damage reliability were derived. Fatigue damage reliability analysis of some critical members of the Nanjing Yangtze river bridge was carried out by using the strain-time histories measured by the structural health monitoring system of the bridge. The corresponding stress spectra were obtained by the real-time rain-flow counting method.Results of fatigue damage were calculated respectively by the reliability method at different reliability and compared with Miner's rule. The results show that the fatigue damage of critical members of the Nanjing Yangtze river bridge is very small due to its low live-load stress level.

  11. Modal analysis of a concrete highway bridge: Structural calculations and vibration-based results

    NARCIS (Netherlands)

    Miao, S.; Veerman, R.P.; Koenders, E.A.B.; Knobbe, A.

    2013-01-01

    In the field of civil infrastructure, Structural Health Monitoring systems are implemented more and more frequently with the aim to safeguard the safety and service-life of structures such as bridges and tunnels. Changes in the integrity of the material and/or structural properties of this class of

  12. Modal analysis of a concrete highway bridge: Structural calculations and vibration-based results

    NARCIS (Netherlands)

    Miao, S.; Veerman, R.P.; Koenders, E.A.B.; Knobbe, A.

    2013-01-01

    In the field of civil infrastructure, Structural Health Monitoring systems are implemented more and more frequently with the aim to safeguard the safety and service-life of structures such as bridges and tunnels. Changes in the integrity of the material and/or structural properties of this class of

  13. Big data and high-performance analytics in structural health monitoring for bridge management

    Science.gov (United States)

    Alampalli, Sharada; Alampalli, Sandeep; Ettouney, Mohammed

    2016-04-01

    Structural Health Monitoring (SHM) can be a vital tool for effective bridge management. Combining large data sets from multiple sources to create a data-driven decision-making framework is crucial for the success of SHM. This paper presents a big data analytics framework that combines multiple data sets correlated with functional relatedness to convert data into actionable information that empowers risk-based decision-making. The integrated data environment incorporates near real-time streams of semi-structured data from remote sensors, historical visual inspection data, and observations from structural analysis models to monitor, assess, and manage risks associated with the aging bridge inventories. Accelerated processing of dataset is made possible by four technologies: cloud computing, relational database processing, support from NOSQL database, and in-memory analytics. The framework is being validated on a railroad corridor that can be subjected to multiple hazards. The framework enables to compute reliability indices for critical bridge components and individual bridge spans. In addition, framework includes a risk-based decision-making process that enumerate costs and consequences of poor bridge performance at span- and network-levels when rail networks are exposed to natural hazard events such as floods and earthquakes. Big data and high-performance analytics enable insights to assist bridge owners to address problems faster.

  14. Operational Modal Analysis of Bridge Structures with Data from GNSS/Accelerometer Measurements.

    Science.gov (United States)

    Xiong, Chunbao; Lu, Huali; Zhu, Jinsong

    2017-02-23

    Real-time dynamic displacement and acceleration responses of the main span section of the Tianjin Fumin Bridge in China under ambient excitation were tested using a Global Navigation Satellite System (GNSS) dynamic deformation monitoring system and an acceleration sensor vibration test system. Considering the close relationship between the GNSS multipath errors and measurement environment in combination with the noise reduction characteristics of different filtering algorithms, the researchers proposed an AFEC mixed filtering algorithm, which is an combination of autocorrelation function-based empirical mode decomposition (EMD) and Chebyshev mixed filtering to extract the real vibration displacement of the bridge structure after system error correction and filtering de-noising of signals collected by the GNSS. The proposed AFEC mixed filtering algorithm had high accuracy (1 mm) of real displacement at the elevation direction. Next, the traditional random decrement technique (used mainly for stationary random processes) was expanded to non-stationary random processes. Combining the expanded random decrement technique (RDT) and autoregressive moving average model (ARMA), the modal frequency of the bridge structural system was extracted using an expanded ARMA_RDT modal identification method, which was compared with the power spectrum analysis results of the acceleration signal and finite element analysis results. Identification results demonstrated that the proposed algorithm is applicable to analyze the dynamic displacement monitoring data of real bridge structures under ambient excitation and could identify the first five orders of the inherent frequencies of the structural system accurately. The identification error of the inherent frequency was smaller than 6%, indicating the high identification accuracy of the proposed algorithm. Furthermore, the GNSS dynamic deformation monitoring method can be used to monitor dynamic displacement and identify the modal

  15. Operational Modal Analysis of Bridge Structures with Data from GNSS/Accelerometer Measurements

    Directory of Open Access Journals (Sweden)

    Chunbao Xiong

    2017-02-01

    Full Text Available Real-time dynamic displacement and acceleration responses of the main span section of the Tianjin Fumin Bridge in China under ambient excitation were tested using a Global Navigation Satellite System (GNSS dynamic deformation monitoring system and an acceleration sensor vibration test system. Considering the close relationship between the GNSS multipath errors and measurement environment in combination with the noise reduction characteristics of different filtering algorithms, the researchers proposed an AFEC mixed filtering algorithm, which is an combination of autocorrelation function-based empirical mode decomposition (EMD and Chebyshev mixed filtering to extract the real vibration displacement of the bridge structure after system error correction and filtering de-noising of signals collected by the GNSS. The proposed AFEC mixed filtering algorithm had high accuracy (1 mm of real displacement at the elevation direction. Next, the traditional random decrement technique (used mainly for stationary random processes was expanded to non-stationary random processes. Combining the expanded random decrement technique (RDT and autoregressive moving average model (ARMA, the modal frequency of the bridge structural system was extracted using an expanded ARMA_RDT modal identification method, which was compared with the power spectrum analysis results of the acceleration signal and finite element analysis results. Identification results demonstrated that the proposed algorithm is applicable to analyze the dynamic displacement monitoring data of real bridge structures under ambient excitation and could identify the first five orders of the inherent frequencies of the structural system accurately. The identification error of the inherent frequency was smaller than 6%, indicating the high identification accuracy of the proposed algorithm. Furthermore, the GNSS dynamic deformation monitoring method can be used to monitor dynamic displacement and identify the

  16. Knowledge-Based Systems for the Assessment and Management of Bridge Structures

    DEFF Research Database (Denmark)

    Miyamoto, A.; Thoft-Christensen, Palle; Yan, B.

    2004-01-01

    . The aim of this paper is to summarize the finding of up-to-date research articles concerning the application of knowledge-based systems to assessment and management of structures and to illustrate the potential of such systems in the structural engineering. Two modern bridge management systems (BMS...

  17. Structural Health Monitoring approach for detecting ice accretion on bridge cable using the Haar Wavelet Transform

    DEFF Research Database (Denmark)

    Andre, Julia; Kiremidjian, Anne; Liao, Yizheng;

    2016-01-01

    Ice accretion on cables of bridge structures poses serious risk to the structure as well as to vehicular traffic when the ice falls onto the road. Detection of ice formation, quantification of the amount of ice accumulated, and prediction of icefalls will increase the safety and serviceability of...

  18. Steel structure (bridge and building); Doboku/kenchiku bun`ya ni okeru yosetsu gijutsu no tenkai

    Energy Technology Data Exchange (ETDEWEB)

    Fukazawa, M. [Yokogawa Bridge Corp., Tokyo (Japan)

    1996-01-05

    In this article, the trends of welding engineering are discussed in two groups, namely bridges and steel frames. First of all, in the field of bridges, as the themes of technical innovation of steel bridges, the challenge to build long span bridges, coping with new structural forms, and rationalization of general bridges are selected. Concerning very long bridges, considerable elongation of its spans and technological development for materials, design, construction and erection relating to improvement of profitability become inevitable. Besides, in addition to the functions of bridges, the bridges playing the roles of environmental and/or artistic structures become many, thereby the cases of using welding for the site joints increase. As the measure for rationalize bridge construction, it is to reduce steel weight and working costs for increasing profitability, and the progress of welding technology therefor has been observed. With regard to the manufacture of bridge portions in a factory, labor saving, automatization and robotization of in-house welding have been made, and bridge maintenance as well as pursuance of attaining the state of maintenance free are also important. The trend that the bridge load is becoming larger and enhancement of earthquake resistance are also important. Regarding steel frames, functionalization of steel, making steel very thick, various automatization of manufacturing, and pursuance of earthquake resistant safety are being made. 14 refs., 7 figs.

  19. Use of FBG sensors for bridge structural monitoring and traffic control

    Science.gov (United States)

    Caponero, Michele A.; Colonna, Danilo; Gruppi, Marco; Pallotta, Massimo; Salvadori, Robert

    2004-06-01

    This paper describes an application of Fiber Bragg Grating sensors devoted to both health monitoring of road bridge structures and traffic load monitoring. The ultimate aim of the application is the remote continuous monitoring of the structures, with real time acquisition of the dynamic and quasi-static deformations inferred by both the road traffic and the daily and seasonal thermal variations. A Fiber Bragg Grating network composed of 24 sensors has been installed on the bridge on the Po river of the 'A21 Torino Brescia' Italian Highway. The bridge is a concrete structure, and sensors are applied on various rebar components. The sensors were installed directly on the rebars, adopting a special technique specifically developed for permanent concrete embedding. An extensive data acquisition program is in progress with the aim of both health monitoring and in transit lorry weighing. Results are discussed and planned future work is presented.

  20. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges

    Directory of Open Access Journals (Sweden)

    M. Stachowicz

    2010-07-01

    Full Text Available Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4 min is very close to that measured after traditional drying at 110 °C for 120 min. So, application of microwave hardening ensures significant shortening of the process time to the value comparable with CO2 hardening but guaranteeing over 10-fold increase of mechanical properties. Analysis of SEM images of hardened moulding sands permitted explaining differences in quality parameters of moulding sands by connecting them with structure of the created bonding bridges.

  1. Application of AN Automated Wireless Structural Monitoring System for Long-Span Suspension Bridges

    Science.gov (United States)

    Kurata, M.; Lynch, J. P.; van der Linden, G. W.; Hipley, P.; Sheng, L.-H.

    2011-06-01

    This paper describes an automated wireless structural monitoring system installed at the New Carquinez Bridge (NCB). The designed system utilizes a dense network of wireless sensors installed in the bridge but remotely controlled by a hierarchically designed cyber-environment. The early efforts have included performance verification of a dense network of wireless sensors installed on the bridge and the establishment of a cellular gateway to the system for remote access from the internet. Acceleration of the main bridge span was the primary focus of the initial field deployment of the wireless monitoring system. An additional focus of the study is on ensuring wireless sensors can survive for long periods without human intervention. Toward this end, the life-expectancy of the wireless sensors has been enhanced by embedding efficient power management schemes in the sensors while integrating solar panels for power harvesting. The dynamic characteristics of the NCB under daily traffic and wind loads were extracted from the vibration response of the bridge deck and towers. These results have been compared to a high-fidelity finite element model of the bridge.

  2. Effect of hardening methods of moulding sands with water glass on structure of bonding bridges

    OpenAIRE

    Stachowicz, M.; K. Granat; Nowak, D.

    2010-01-01

    Research on influence of hardening methods on structure of bonding bridges in moulding sands with sodium water glass is presented.Moulding sands with addition of 2.5 % of binder with molar module 2.0 were hardened with CO2 and dried in traditional way or hardenedwith microwaves. It was proved that the hardening method affects structure of bonding bridges, correlating with properties of the hardened moulding sands. It was found that strength of the moulding sands hardened with microwaves for 4...

  3. Structural and functional characterization of the conserved salt bridge in mammalian paneth cell alpha-defensins

    DEFF Research Database (Denmark)

    Rosengren, K Johan; Daly, Norelle L; Fornander, Liselotte M;

    2006-01-01

    )-Crp4 peptide, in which a conserved Glu(15) residue was replaced by Asp. Structural analysis of the two peptides confirms the involvement of this Glu in a conserved salt bridge that is removed in the mutant because of the shortened side chain. Despite disruption of this structural feature, the peptide...... variant retains a well defined native fold because of a rearrangement of side chains, which result in compensating favorable interactions. Furthermore, salt bridge-deficient Crp4 mutants were tested for bactericidal effects and resistance to proteolytic degradation, and all of the variants had similar...

  4. Vibration based structural assessment of the rehabilitation intervention in r.c. segmental bridge

    Directory of Open Access Journals (Sweden)

    Franchetti Paolo

    2015-01-01

    Full Text Available A vibration based structural assessment campaign was carried out on a r.c. segmental bridge in North East Italy. The bridge has a cantilever static scheme, fixed at the top of the piers and with a hinge at the centre of the span. The particular configuration of the hinge consists in a couple of steel elements, each one composed by a tongue and groove joint. Since the year 1960, the hinge was subjected to consumption and degradation, that caused a malfunctioning of the device. An intervention of rehabilitation of the bridge led to a reinforcement of the existing hinges with the coupling of new metallic devices: new tongue and groove hinges were applied, that by one side allow the horizontal displacements and rotation, by the other side strongly reduce the relative vertical displacements of the two parts of the bridge. A dynamic test campaign was set up in order to assess the effectiveness of the intervention. The principal dynamic parameters were calculated and analysed with respect to the intervention that was realized. The tests clearly showed the effectiveness of the intervention, and helped the designer to have a better understanding of the structural behaviour of the bridge.

  5. Specifications and applications of the technical code for monitoring of building and bridge structures in China

    Directory of Open Access Journals (Sweden)

    Y Yang

    2016-12-01

    Full Text Available Recently, the exclusive compulsory technical code (GB 50982-2014 for structural health monitoring of buildings and bridges in China has been developed and implemented. This code covers the majority of the field monitoring methods and stipulates the corresponding technical parameters for monitoring of high-rise structures, large-span spatial structures, bridges and base-isolated structures. This article first presents the comprehensive review and linear comparison of existing structural health monitoring codes and standards. Subsequently, the progress of the codification of GB 50982-2014 is imparted and its main features and specifications are summarized. Finally, in accordance with GB50982-2014, several representative structural health monitoring practical applications of large-scale infrastructures in China are exemplified to illustrate how this national code can bridge the gap between theory and practical applications of structural health monitoring. This technical code is an important milestone in the application of well-established structural health monitoring techniques into the realistic and complex engineering projects. Also, it can provide abundant and authoritative information for practitioners and researchers involving the structural health monitoring techniques.

  6. GPS for structural health monitoring: A case study on the Basarab overpass cable-stayed bridge

    NARCIS (Netherlands)

    Lepadatu, L.; Tiberius, C.C.J.M.

    2014-01-01

    The Basarab cable-stayed bridge is a newly built structure in Bucharest, Romania, which was inaugurated in June 2011. Before the oficial opening, in order to assure its qualification for trafic, it had to pass several loading tests with convoys of trucks and trams. For this, besides a priori evaluat

  7. Connecting parameters optimization on unsymmetrical twin-tower structure linked by sky-bridge

    Institute of Scientific and Technical Information of China (English)

    孙黄胜; 刘默涵; 朱宏平

    2014-01-01

    Based on a simplified 3-DOF model of twin-tower structure linked by a sky-bridge, the frequency response functions, the displacement power spectral density (PSD) functions, and the time-averaged total vibration energy were derived, by assuming the white noise as the earthquake excitation. The effects of connecting parameters, such as linking stiffness ratio and linking damping ratio, on the structural vibration responses were then studied, and the optimal connecting parameters were obtained to minimize the vibration energy of either the independent monomer tower or the integral structure. The influences of sky-bridge elevation position on the optimal connecting parameters were also discussed. Finally, the distribution characteristics of the top displacement PSD and the structural responses, excited by El Centro, Taft and artificial waves, were compared in both frequency and time domain. It is found that the connecting parameters at either end of connection interactively affect the responses of the towers. The optimal connecting parameters can greatly improve the damping connections on their seismic reduction effectiveness, but are unable to reduce the seismic responses of the towers to the best extent simultaneously. It is also indicated that the optimal connecting parameters derived from the simplified 3-DOF model are applicable for two multi-story structures linked by a sky-bridge with dampers. The seismic reduction effectiveness obtained varies from 0.3 to 1.0 with different sky-bridge mass ratio. The displacement responses of the example structures are reduced by approximately 22% with sky-bridge connections.

  8. structural reliability of the nigerian grown abura timber bridge beam ...

    African Journals Online (AJOL)

    ENGR. J. I. AGUWA

    2013-07-02

    Jul 2, 2013 ... Structural reliability analysis was carried out on the Nigerian grown Abura timber, to ascertain its structural ... wall sheeting, formwork and furniture. The ... reinforced concrete members. ... fulfill certain performance criteria related to safety and ..... Plastic Structures” First Edition, Mir Publishers. Moscow ...

  9. A new solution of measuring thermal response of prestressed concrete bridge girders for structural health monitoring

    Science.gov (United States)

    Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

    2017-08-01

    This study develops a novel buckling-based mechanism to measure the thermal response of prestressed concrete bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to concrete bridge girders, the electrical signals are used to detect the thermal response of concrete bridges. Finite element simulations are conducted to obtain the displacement of prestressed concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler-Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on concrete bridge girders. The proposed solution sufficiently measures the thermal response of concrete bridges.

  10. Influence of a Hydrophobic Environment on the Structure of Arginine—Carboxylate Salt Bridge

    Institute of Scientific and Technical Information of China (English)

    封勇; 刘磊; 穆廷巍; 郭庆祥

    2002-01-01

    The exact structure of an arginine-carboxylate salt bridge in different chemical environments remains a controversial problem.In the present work,the zwitterionic and neutral forms of arginine-carboxylate salt bridge were studied by the B3LYP/6-311G(d,p)//PM3 method.It turns out that the neutral forms are more stable than the zwitterionic coumterparts in gas phase.However,whnen bound by α-cyclodextrin,the zwitterionic forms become more stable than the corresponding neutral ones.It is suggested that the hydrophobic environment provided by the cyclodextrin cavity leads to such behavior.Therefore,the salt bridge still could be in a zwitterionic form in the hydrophobic interior of the real proteins.

  11. Influence of a Hydrophobic Environment on the Structure of Arginine-Carboxylate Salt Bridge

    Institute of Scientific and Technical Information of China (English)

    FENG,Yong(封勇); LIU,Lei(刘磊); MU,Ting-Wei(穆廷巍); GUO,Qing-Xiang(郭庆祥)

    2002-01-01

    The exact structure of an arginine-carboxylate salt bridge in different chemical environments remains a controversial problem. In the present work, the zwitterionic and neutral forms of arginine-carboxylate salt bridge were studied by the B3LYP/6-311G(d,p)//PM3 method. It turns out that the neutral forms are more stable than the zwitterionic counterparis in gas phase.However, when bound by c-cyclodextrin, the zwitterionic forms become more stable than the corresponding neutral ones.It is suggested that the hydrophobic environment provided by the cyclodextrin cavity leads to such behavior. Tnerefore, the salt bridge still could be in a zwitterionic form in the hydrophobic interior of the real proteins.

  12. Assesment of Severely ASR Damaged Bridges: From Diagnosis to Structural Effects

    DEFF Research Database (Denmark)

    Barbosa, Ricardo Antonio; Hansen, Søren Gustenhoff; Hansen, Kurt Kielsgaard;

    2016-01-01

    During the last decade an increasing number of bridges are becoming severely deteriorated due to alkali-silica reaction (ASR) in Denmark. Some bridges have already been demolished due to lack of knowledge on the residual load carrying capacity. The deterioration of concrete by ASR has been widely...... documented. The majority of the experimental data are based on relatively small scale laboratory specimens accelerated by various exposure conditions. Research on assessment and influence of severely ASR deterioration on the material properties and residual load carrying capacity of real-life structures...... is unfortunately limited. This paper presents an overview and discussion of the Danish experiences with assessment of the residual load carrying capacity of severely non-shear reinforced ASR damaged bridges. The discussion is supported by experimental data acquired from large scale in-situ tests of three severely...

  13. Real-time visualization of bridge structural response through wireless MEMS sensors

    Science.gov (United States)

    Chung, Hung-Chi; Enomoto, Tomoyuki; Loh, Kenneth; Shinozuka, Masanobu

    2004-07-01

    This study investigates the reliability and accuracy of wireless micro-electromechanical-system (MEMS)-type sensors in application of bridge structural vibration monitoring. With wireless capabilities added onto the developed sensors, it becomes unnecessary for engineers to connect enormous lengths of cables in order to measure vibration on bridges for instance. We investigated two types of MEMS accelerometers: the ADXL 202E and the Silicon Design 2210. To prove the validity of measuring acceleration by using these devices with wireless communication, we succeeded on measuring a pedestrian bridge's vibration under excitation loads in the center of span. The result had been compared with the traditional cabled sensor, PCB 393C. The wireless sensors were showed to be effective and much affordable to carry out the monitoring missions in situ.

  14. SEMICONDUCTOR DEVICES MEMS magnetic field sensor based on silicon bridge structure

    Science.gov (United States)

    Guangtao, Du; Xiangdong, Chen; Qibin, Lin; Hui, Li; Huihui, Guo

    2010-10-01

    A MEMS piezoresistive magnetic field sensor based on a silicon bridge structure has been simulated and tested. The sensor consists of a silicon sensitivity diaphragm embedded with a piezoresistive Wheatstone bridge, and a ferromagnetic magnet adhered to the sensitivity diaphragm. When the sensor is subjected to an external magnetic field, the magnetic force bends the silicon sensitivity diaphragm, producing stress and resistors change of the Wheatstone bridge and the output voltage of the sensor. Good agreement is observed between the theory and measurement behavior of the magnetic field sensor. Experimental results demonstrate that the maximum sensitivity and minimum resolution are 48 m V/T and 160 μT, respectively, making this device suitable for strong magnetic field measurement. Research results indicate that the sensor repeatability and dynamic response time are about 0.66% and 150 ms, respectively.

  15. Building bridges between cellular and molecular structural biology.

    Science.gov (United States)

    Patwardhan, Ardan; Brandt, Robert; Butcher, Sarah J; Collinson, Lucy; Gault, David; Grünewald, Kay; Hecksel, Corey; Huiskonen, Juha T; Iudin, Andrii; Jones, Martin L; Korir, Paul K; Koster, Abraham J; Lagerstedt, Ingvar; Lawson, Catherine L; Mastronarde, David; McCormick, Matthew; Parkinson, Helen; Rosenthal, Peter B; Saalfeld, Stephan; Saibil, Helen R; Sarntivijai, Sirarat; Solanes Valero, Irene; Subramaniam, Sriram; Swedlow, Jason R; Tudose, Ilinca; Winn, Martyn; Kleywegt, Gerard J

    2017-07-06

    The integration of cellular and molecular structural data is key to understanding the function of macromolecular assemblies and complexes in their in vivo context. Here we report on the outcomes of a workshop that discussed how to integrate structural data from a range of public archives. The workshop identified two main priorities: the development of tools and file formats to support segmentation (that is, the decomposition of a three-dimensional volume into regions that can be associated with defined objects), and the development of tools to support the annotation of biological structures.

  16. Toward structural mechanics through wooden bridges in France (1716-1841)

    CERN Document Server

    Tardini, Chiara

    2014-01-01

    Early applications of Navier’s beam theory to the rational design of structures are documented in the Annales of the French Ecole des Ponts et Chaussées and refer to the design of three wooden bridges built in France in the 1840's. Revisiting these examples, the book provides documentation on the progressive establishment of the new design approach, based on the theory of structural mechanics rather than empirical knowledge. The bridges concerned were built according to the structural scheme patented by Ithiel Town in the USA, witnessing the diffusion in Europe of the American advancements in bridge design, circulated by the travel reports of French engineers from the Ecole. Through the exam of French treatises discussing the progress of theoretical formulations in parallel with experimental findings in the 18th and 19th centuries, the book retraces as well the long path which led to the formulation of Navier’s theory. The relevant scientific debate dealt mainly with the specific case of wood bridges; th...

  17. Analysis of steel-concrete composite structure with overlap slab of Xingguang bridge

    Institute of Scientific and Technical Information of China (English)

    YE Mei-xin; HUANG Qiong; WU Qin-qin

    2007-01-01

    Finire element modeling methods of steel-concrete composire structure with overlap slab were investigated.A two-step finite element method wag presented.It was applied to analyze an extra long span composite bridge.The conversion of structure system and the mechanical behavior of the bridge were analyzed with two different construction methods.The stresses of steel beams, precast slabs and in-situ-place concrete under the total load were compared. The results show that steel-concrete composite structure with overlap slab has many advantages, the construction method that the top in-situ concrete and the concrete in construction joints are cast respectively is rather reasonable than the one that the top in-situ concrete and the concrete in construction joints are cast at the same time, and the two-step finite element method is affective to such large-scale structures.

  18. Reliability Analysis-Based Numerical Calculation of Metal Structure of Bridge Crane

    Directory of Open Access Journals (Sweden)

    Wenjun Meng

    2013-01-01

    Full Text Available The study introduced a finite element model of DQ75t-28m bridge crane metal structure and made finite element static analysis to obtain the stress response of the dangerous point of metal structure in the most extreme condition. The simulated samples of the random variable and the stress of the dangerous point were successfully obtained through the orthogonal design. Then, we utilized BP neural network nonlinear mapping function trains to get the explicit expression of stress in response to the random variable. Combined with random perturbation theory and first-order second-moment (FOSM method, the study analyzed the reliability and its sensitivity of metal structure. In conclusion, we established a novel method for accurately quantitative analysis and design of bridge crane metal structure.

  19. A structural homologue of colipase in black mamba venom revealed by NMR floating disulphide bridge analysis.

    Science.gov (United States)

    Boisbouvier, J; Albrand, J P; Blackledge, M; Jaquinod, M; Schweitz, H; Lazdunski, M; Marion, D

    1998-01-01

    The solution structure of mamba intestinal toxin 1 (MIT1), isolated from Dendroaspis polylepis polylepis venom, has been determined. This molecule is a cysteine-rich polypeptide exhibiting no recognised family membership. Resistance to MIT1 to classical specific endoproteases produced contradictory NMR and biochemical information concerning disulphide-bridge topology. We have used distance restraints allowing ambiguous partners between S atoms in combination with NMR-derived structural information, to correctly determine the disulphide-bridge topology. The resultant solution structure of MIT1, determined to a resolution of 0.5 A, reveals an unexpectedly similar global fold with respect to colipase, a protein involved in fatty acid digestion. Colipase exhibits an analogous resistance to endoprotease activity, indicating for the first time the possible topological origins of this biochemical property. The biochemical and structural homology permitted us to propose a mechanically related digestive function for MIT1 and provides novel information concerning snake venom protein evolution. Copyright 1998 Academic Press.

  20. Doubly chloro bridged dimeric copper(II) complex: magneto-structural correlation and anticancer activity.

    Science.gov (United States)

    Sikdar, Yeasin; Modak, Ritwik; Bose, Dipayan; Banerjee, Saswati; Bieńko, Dariusz; Zierkiewicz, Wiktor; Bieńko, Alina; Das Saha, Krishna; Goswami, Sanchita

    2015-05-21

    We have synthesized and structurally characterized a new doubly chloro bridged dimeric copper(II) complex, [Cu2(μ-Cl)2(HL)2Cl2] (1) based on a Schiff base ligand, 5-[(pyridin-2-ylmethylene)-amino]-pentan-1-ol). Single crystal X-ray diffraction shows the presence of dinuclear copper(II) centres in a square pyramidal geometry linked by obtuse double chloro bridge. The magnetic study illustrated that weak antiferromagnetic interactions (J = -0.47 cm(-1)) prevail in complex 1 which is well supported by magneto-structural correlation. This compound adds to the library of doubly chloro bridged copper(ii) complexes in the regime of spin state cross over. DFT calculations have been conducted within a broken-symmetry (BS) framework to investigate the exchange interaction further which depicts that the approximate spin projection technique yields the best corroboration of the experimental J value. Spin density plots show the presence of an ∼0.52e charge residing on the copper atom along with a substantial charge on bridging and peripheral chlorine atoms. The potential of complex1 to act as an anticancer agent is thoroughly examined on a series of liver cancer cell lines and screening shows the HepG2 cell line exhibits maximum cytotoxicity by phosphatidyl serine exposure in the outer cell membrane associated with ROS generation and mitochondrial depolarization with increasing time in the in vitro model system.

  1. Long-term assessment of an autonomous wireless structural health monitoring system at the new Carquinez Suspension Bridge

    Science.gov (United States)

    Kurata, Masahiro; Kim, Junhee; Zhang, Yilan; Lynch, Jerome P.; van der Linden, G. W.; Jacob, Vince; Thometz, Ed; Hipley, Pat; Sheng, Li-Hong

    2011-04-01

    A dense network of sensors installed in a bridge can continuously generate response data from which the health and condition of the bridge can be analyzed. This approach to structural health monitoring the efforts associated with periodic bridge inspections and can provide timely insight to regions of the bridge suspected of degradation or damage. Nevertheless, the deployment of fine sensor grids on large-scale structures is not feasible using wired monitoring systems because of the rapidly increasing installation labor and costs required. Moreover, the enormous size of raw sensor data, if not translated into meaningful forms of information, can paralyze the bridge manager's decision making. This paper reports the development of a large-scale wireless structural monitoring system for long-span bridges; the system is entirely wireless which renders it low-cost and easy to install. Unlike central tethered data acquisition systems where data processing occurs in the central server, the distributed network of wireless sensors supports data processing. In-network data processing reduces raw data streams into actionable information of immediate value to the bridge manager. The proposed wireless monitoring system has been deployed on the New Carquinez Suspension Bridge in California. Current efforts on the bridge site include: 1) long-term assessment of a dense wireless sensor network; 2) implementation of a sustainable power management solution using solar power; 3) performance evaluation of an internet-enabled cyber-environment; 4) system identification of the bridge; and 5) the development of data mining tools. A hierarchical cyber-environment supports peer-to-peer communication between wireless sensors deployed on the bridge and allows for the connection between sensors and remote database systems via the internet. At the remote server, model calibration and damage detection analyses that employ a reduced-order finite element bridge model are implemented.

  2. Synthesis and Crystal Structure of a Binuclear Gadolinium(Ⅲ) Complex Bridged by Cucurbit[6]uril

    Institute of Scientific and Technical Information of China (English)

    Gui Ling ZHANG; Zhi Yong WU; Yan Tuan LI; Da Qi WANG; Jian Min DOU

    2006-01-01

    A new cucurbit[6]uril bridged binuclear complex {[Gd(H2O)6]2[Q6(H2O)]}Cl6·4H2O,where Q6 represents cucurbit[6]uril, has been synthesized and characterized by X-ray diffraction.The crystal structure shows that the complex has an extended cucurbit[6]uril-bridged structure consisting of two gadolinium(Ⅲ) ions, in which each gadolinium(Ⅲ) ion is coordinated with two neighboring carbonylic oxygen atoms of Q6 and six oxygen atoms of water molecules that leans toward one side of the portal. One disordered guest water molecule resides in the Q6 molecule cavity and occupies two different positions. Hydrogen bonds assemble the complex to three-dimensional supramolecular structure.

  3. Deployment of a Smart Structural Health Monitoring System for Long-Span Arch Bridges: A Review and a Case Study.

    Science.gov (United States)

    Chen, Zengshun; Zhou, Xiao; Wang, Xu; Dong, Lili; Qian, Yuanhao

    2017-09-19

    Structural health monitoring (SHM) technology for surveillance and evaluation of existing and newly built long-span bridges has been widely developed, and the significance of the technique has been recognized by many administrative authorities. The paper reviews the recent progress of the SHM technology that has been applied to long-span bridges. The deployment of a SHM system is introduced. Subsequently, the data analysis and condition assessment including techniques on modal identification, methods on signal processing, and damage identification were reviewed and summarized. A case study about a SHM system of a long-span arch bridge (the Jiubao bridge in China) was systematically incorporated in each part to advance our understanding of deployment and investigation of a SHM system for long-span arch bridges. The applications of SHM systems of long-span arch bridge were also introduced. From the illustrations, the challenges and future trends for development a SHM system were concluded.

  4. The application of structural health monitoring system technology using FBG to the No. 2 Wuhan bridge over the Yangtze river

    Science.gov (United States)

    Liu, Shengchun; Jiang, Desheng

    2008-12-01

    Bridge engineering offer many unique opportunities for the use of advanced optical fiber sensing technology. In this paper, the state-of-the-art of bridge structural health monitoring system(SHMS) based on optical fiber sensing technology are reviewed and some disadvantages in present SHMS based on optical fiber sensing technology for existing long-span bridge are indicated. In order to overcome those disadvantages, some fiber Bragg grating (FBG) products developed by authors and corresponding industrialization enterprise are introduced. Focusing on an existing long-span cable-stayed bridge-Wuhan Yangtze No.2 Bridge, the operational condition of the multi-parameter bridge SHMS mainly based on FBG sensors is presented. Some initial monitoring results show that the whole performance of the SHMS FBGbased is reliable and measuring data are reasonable.

  5. Distributed strain monitoring for bridges: temperature effects

    Science.gov (United States)

    Regier, Ryan; Hoult, Neil A.

    2014-03-01

    To better manage infrastructure assets as they reach the end of their service lives, quantitative data is required to better assess structural behavior and allow for more informed decision making. Distributed fiber optic strain sensors are one sensing technology that could provide comprehensive data for use in structural assessments as these systems potentially allow for strain to be measured with the same accuracy and gage lengths as conventional strain sensors. However, as with many sensor technologies, temperature can play an important role in terms of both the structure's and sensor's performance. To investigate this issue a fiber optic distributed strain sensor system was installed on a section of a two span reinforced concrete bridge on the TransCanada Highway. Strain data was acquired several times a day as well as over the course of several months to explore the effects of changing temperature on the data. The results show that the strain measurements are affected by the bridge behavior as a whole. The strain measurements due to temperature are compared to strain measurements that were taken during a load test on the bridge. The results show that even a small change in temperature can produce crack width and strain changes similar to those due to a fully loaded transport truck. Future directions for research in this area are outlined.

  6. Structural Optimization of Steel Cantilever Used in Concrete Box Girder Bridge Widening

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2015-01-01

    Full Text Available The structural optimization method of steel cantilever used in concrete box girder bridge widening is illustrated in this paper. The structural optimization method of steel cantilever incorporates the conceptual layout design of steel cantilever beam based on the topological theory and the determination of the optimal location of the transverse external prestressed tendons which connect the steel cantilever and the box girder. The optimal design theory and the analysis process are illustrated. The mechanical model for the prestressed steel cantilever is built and the analytical expression of the optimal position of the transverse external tendon is deduced. At last the effectiveness of this method is demonstrated by the design of steel cantilevers which are used to widen an existing bridge.

  7. Structural condition assessment of long-span suspension bridges using long-term monitoring data

    Science.gov (United States)

    Yang, Deng; Youliang, Ding; Aiqun, Li

    2010-03-01

    This paper focuses on developing an online structural condition assessment technique using long-term monitoring data measured by a structural health monitoring system. The seasonal correlations of frequency-temperature and beam-end displacement-temperature for the Runyang Suspension Bridge are performed, first. Then, a statistical modeling technique using a six-order polynomial is further applied to formulate the correlations of frequency-temperature and displacement-temperature, from which abnormal changes of measured frequencies and displacements are detected using the mean value control chart. Analysis results show that modal frequencies of higher vibration modes and displacements have remarkable seasonal correlations with the environmental temperature and the proposed method exhibits a good capability for detecting the micro damage-induced changes of modal frequencies and displacements. The results demonstrate that the proposed method can effectively eliminate temperature complications from frequency and displacement time series and is well suited for online condition monitoring of long-span suspension bridges.

  8. Structural Health Monitoring Studies of the Alamosa Canyon and I-40 Bridges

    Energy Technology Data Exchange (ETDEWEB)

    Charles R. Farrar; Phillip J. Cornwell; Scott W. Doebling; Michael B. Prime

    2000-07-01

    From 1994 to 1997 internal research grants from Los Alamos National Laboratory's Laboratory Direct Research and Development (LDRD) office were used to fund an effort aimed at studying global vibration-based damage detection methods. To support this work, several field tests of the Alamosa Canyon Bridge have been performed to study various aspects of applying vibration-based damage detection methods to a real world in situ structure. This report summarizes the data that has been collected from the various vibration tests performed on the Alamosa Canyon Bridge, analyses of these data, and the results that have been obtained. Initially, it was the investigators' intent to introduce various types of damage into this bridge and study several vibration-based damage detection methods. The feasibility of continuously monitoring such a structure for the onset of damage was also going to be studied. However, the restrictions that the damage must be relatively benign or repairable made it difficult to take the damage identification portion of the study to completion. Subsequently, this study focused on quantifying the variability in identified modal parameters caused by sources other than damage. These sources include variability in testing procedures, variability in test conditions, and environmental variability. These variabilities must be understood and their influence on identified modal properties quantified before vibration-based damage detection can be applied with unambiguous results. Quantifying the variability in the identified modal parameters led to the development of statistical analysis procedures that can be applied to the experimental modal analysis results. It is the authors' opinion that these statistical analysis procedures represent one of the major contributions of these studies to the vibration-based damage detection field. Another significant contribution that came from this portion of the study was the extension of a strain

  9. Supramolecular architecture, crystal structure and transport properties of the prototypal oxobenzene-bridged bisdithiazolyl radical conductor.

    Science.gov (United States)

    Wong, Joanne W L; Mailman, Aaron; Winter, Stephen M; Robertson, Craig M; Holmberg, Rebecca J; Murugesu, Muralee; Dube, Paul A; Oakley, Richard T

    2014-01-25

    Supramolecular CHπ interactions cause a ruffling of the otherwise coplanar ribbon-like arrays of radicals in the structure of the oxobenzene-bridged bisdithiazolyl . The material displays a conductivity σ(300 K) = 6 × 10(-3) S cm(-1) (Eact = 0.16 eV) and orders antiferromagnetically below 4 K. At applied fields above 1 kOe the material displays metamagnetic behavior.

  10. TECHNOLOGY AND EFFICIENT USE OF PEAT ASH IN MASTICS FOR WATERPROOFING OF BRIDGE AND TUNNEL STRUCTURES

    OpenAIRE

    G. D. Lyahevich; A. G. Lyahevich; Agababa Rangraz Alireza Najib; A. A. Dalidovskaya

    2015-01-01

    A prospective method for protection of  bridges and tunnels against aggressive water action is surface waterproofing on the basis of an organo-mineral binder. Its structural strength can be increased by introduction of particles which are similar to the size of  asphaltenes and an elasticity of disperse medium has been increased due to introduction of polymers. These theoretical suppositions point out the possibility for simultaneous provision of flexibility at low temperatures and high heat ...

  11. Structural features of cross-bridges in isometrically contracting skeletal muscle.

    OpenAIRE

    Kraft, Theresia; Mattei, Thomas; Radocaj, Ante; Piep, Birgit; Nocula, Christoph; Furch, Markus; Brenner, Bernhard

    2002-01-01

    Two-dimensional x-ray diffraction was used to investigate structural features of cross-bridges that generate force in isometrically contracting skeletal muscle. Diffraction patterns were recorded from arrays of single, chemically skinned rabbit psoas muscle fibers during isometric force generation, under relaxation, and in rigor. In isometric contraction, a rather prominent intensification of the actin layer lines at 5.9 and 5.1 nm and of the first actin layer line at 37 nm was found compared...

  12. Real-time kinematic PPP GPS for structure monitoring applied on the Severn Suspension Bridge, UK

    Science.gov (United States)

    Tang, Xu; Roberts, Gethin Wyn; Li, Xingxing; Hancock, Craig Matthew

    2017-09-01

    GPS is widely used for monitoring large civil engineering structures in real time or near real time. In this paper the use of PPP GPS for monitoring large structures is investigated. The bridge deformation results estimated using double differenced measurements is used as the truth against which the performance of kinematic PPP in a real-time scenario for bridge monitoring is assessed. The towers' datasets with millimetre level movement and suspension cable dataset with centimetre/decimetre level movement were processed by both PPP and DD data processing methods. The consistency of tower PPP time series indicated that the wet tropospheric delay is the major obstacle for small deflection extraction. The results of suspension cable survey points indicate that an ionospheric-free linear measurement is competent for bridge deformation by PPP kinematic model, the frequency domain analysis yields very similar results using either PPP or DD. This gives evidence that PPP can be used as an alternative method to DD for large structure monitoring when DD is difficult or impossible because of large baseline lengths, power outages or natural disasters. The PPP residual tropospheric wet delays can be applied to improve the capacity of small movement extraction.

  13. A spectral-based clustering for structural health monitoring of the Sydney Harbour Bridge

    Science.gov (United States)

    Alamdari, Mehrisadat Makki; Rakotoarivelo, Thierry; Khoa, Nguyen Lu Dang

    2017-03-01

    This paper presents the results of a large scale Structural Health Monitoring application on the Sydney Harbour Bridge in Australia. This bridge has many structural components, and our work focuses on a subset of 800 jack arches under the traffic lane 7. Our goal is to identify which of these jack arches (if any) respond differently to the traffic input, due to potential structural damages or instrumentation issues. We propose a novel non-model-based method to achieve this objective, using a spectrum-driven feature based on the Spectral Moments (SMs) from measured responses from the jack arches. SMs contain information from the entire frequency range, thus subtle differences between the normal signals and distorted ones could be identified. Our method then applies a modified k-means- clustering algorithm to these features, followed by a selection mechanism on the clustering results to identify jack arches with abnormal responses. We performed an extensive evaluation of the proposed method using real data from the bridge. This evaluation included a control component, where the approach successfully detected jack arches with already known damage or issues. It also included a test component, which applied the method to a large set of nodes over a month of data to detect any potential anomaly. The detected anomalies turned out to have indeed system issues after further investigations.

  14. Effect of hardening method and structure of linking bridges on strength of water glass moulding sands

    Directory of Open Access Journals (Sweden)

    M. Stachowicz

    2010-04-01

    Full Text Available The paper presents examination results of the effect of four hardening methods on structure of linking bridges in sandmixes containing hydrated sodium silicate. Test pieces prepared of the moulding sands containing 2.5 % of a binder with molar module between 2.4 and 2.6 were hardened with carbon dioxide, dried traditionally in an oven and hardened with microwaves at 2.54 GHz or using a combination of the CO2 process and microwave heating. It was revealed that the hardening method influences structure of linking bridges and is correlated with mechanical properties of the hardened moulding sands. It was found that strength of the moulding sands microwave-heated for 240 s is approximate to that measured after traditional drying for 120 min at 110 °C. So, the microwave hardening permits significant reduction of the process time, comparable to the CO2 hardening, at the same time guaranteeing over 10 times higher mechanical properties. Analysis of SEM photographs of the moulding sands hardened with the mentioned methods allow explaining differences in qualitative parameters of the moulding sands and their relation to structures of the created linking bridges.

  15. Structural features of cross-bridges in isometrically contracting skeletal muscle.

    Science.gov (United States)

    Kraft, Theresia; Mattei, Thomas; Radocaj, Ante; Piep, Birgit; Nocula, Christoph; Furch, Markus; Brenner, Bernhard

    2002-05-01

    Two-dimensional x-ray diffraction was used to investigate structural features of cross-bridges that generate force in isometrically contracting skeletal muscle. Diffraction patterns were recorded from arrays of single, chemically skinned rabbit psoas muscle fibers during isometric force generation, under relaxation, and in rigor. In isometric contraction, a rather prominent intensification of the actin layer lines at 5.9 and 5.1 nm and of the first actin layer line at 37 nm was found compared with those under relaxing conditions. Surprisingly, during isometric contraction, the intensity profile of the 5.9-nm actin layer line was shifted toward the meridian, but the resulting intensity profile was different from that observed in rigor. We particularly addressed the question whether the differences seen between rigor and active contraction might be due to a rigor-like configuration of both myosin heads in the absence of nucleotide (rigor), whereas during active contraction only one head of each myosin molecule is in a rigor-like configuration and the second head is weakly bound. To investigate this question, we created different mixtures of weak binding myosin heads and rigor-like actomyosin complexes by titrating MgATPgammaS at saturating [Ca2+] into arrays of single muscle fibers. The resulting diffraction patterns were different in several respects from patterns recorded under isometric contraction, particularly in the intensity distribution along the 5.9-nm actin layer line. This result indicates that cross-bridges present during isometric force generation are not simply a mixture of weakly bound and single-headed rigor-like complexes but are rather distinctly different from the rigor-like cross-bridge. Experiments with myosin-S1 and truncated S1 (motor domain) support the idea that for a force generating cross-bridge, disorder due to elastic distortion might involve a larger part of the myosin head than for a nucleotide free, rigor cross-bridge.

  16. Optimal Image Stitching for Concrete Bridge Bottom Surfaces Aided by 3d Structure Lines

    Science.gov (United States)

    Liu, Yahui; Yao, Jian; Liu, Kang; Lu, Xiaohu; Xia, Menghan

    2016-06-01

    Crack detection for bridge bottom surfaces via remote sensing techniques is undergoing a revolution in the last few years. For such applications, a large amount of images, acquired with high-resolution industrial cameras close to the bottom surfaces with some mobile platform, are required to be stitched into a wide-view single composite image. The conventional idea of stitching a panorama with the affine model or the homographic model always suffers a series of serious problems due to poor texture and out-of-focus blurring introduced by depth of field. In this paper, we present a novel method to seamlessly stitch these images aided by 3D structure lines of bridge bottom surfaces, which are extracted from 3D camera data. First, we propose to initially align each image in geometry based on its rough position and orientation acquired with both a laser range finder (LRF) and a high-precision incremental encoder, and these images are divided into several groups with the rough position and orientation data. Secondly, the 3D structure lines of bridge bottom surfaces are extracted from the 3D cloud points acquired with 3D cameras, which impose additional strong constraints on geometrical alignment of structure lines in adjacent images to perform a position and orientation optimization in each group to increase the local consistency. Thirdly, a homographic refinement between groups is applied to increase the global consistency. Finally, we apply a multi-band blending algorithm to generate a large-view single composite image as seamlessly as possible, which greatly eliminates both the luminance differences and the color deviations between images and further conceals image parallax. Experimental results on a set of representative images acquired from real bridge bottom surfaces illustrate the superiority of our proposed approaches.

  17. Long-term structural health monitoring of the 2006 Torino's Olympic pedestrian cabled-stayed bridge

    Science.gov (United States)

    Giacosa, L. M.; De Stefano, A.

    2009-03-01

    The currently project is focused on monitoring the reliability, the static and dynamic conditions of the Pedestrian Olympic Bridge in Torino, Italy. Smart sensors based on fiber optic sensors, realized by University of Illinois at Chicago, were installed on the cables. In parallel new low-cost accelerometers and inclinometers sensors, realized by the ChiLab, Italy), were installed on the bridge deck to control statically but also dynamically its behaviour. Acquisition system to collect the data through a continuous monitoring platform, able to pre-process the data, was integrated to manage it locally or in remote way. The performance and reliability of civil infrastructure systems such as bridges are governed by a number of factors including the actual operating and loading environments, complex interactions between structural members and systems, and defect, deterioration and damage mechanisms. These factors are studied dynamically with structural identification of various levels of uncertainty which can be attributed to the fabricated-constructed-erected nature of these systems, variability in site characteristics and conditions, material properties and service loads, and direct exposure to the environment over long life-cycles that are often many decades in length.

  18. Identification of moving vehicle forces on bridge structures via moving average Tikhonov regularization

    Science.gov (United States)

    Pan, Chu-Dong; Yu, Ling; Liu, Huan-Lin

    2017-08-01

    Traffic-induced moving force identification (MFI) is a typical inverse problem in the field of bridge structural health monitoring. Lots of regularization-based methods have been proposed for MFI. However, the MFI accuracy obtained from the existing methods is low when the moving forces enter into and exit a bridge deck due to low sensitivity of structural responses to the forces at these zones. To overcome this shortcoming, a novel moving average Tikhonov regularization method is proposed for MFI by combining with the moving average concepts. Firstly, the bridge-vehicle interaction moving force is assumed as a discrete finite signal with stable average value (DFS-SAV). Secondly, the reasonable signal feature of DFS-SAV is quantified and introduced for improving the penalty function (∣∣x∣∣2 2) defined in the classical Tikhonov regularization. Then, a feasible two-step strategy is proposed for selecting regularization parameter and balance coefficient defined in the improved penalty function. Finally, both numerical simulations on a simply-supported beam and laboratory experiments on a hollow tube beam are performed for assessing the accuracy and the feasibility of the proposed method. The illustrated results show that the moving forces can be accurately identified with a strong robustness. Some related issues, such as selection of moving window length, effect of different penalty functions, and effect of different car speeds, are discussed as well.

  19. Energy harvesting from electrospun piezoelectric nanofibers for structural health monitoring of a cable-stayed bridge

    Science.gov (United States)

    Maruccio, Claudio; Quaranta, Giuseppe; De Lorenzis, Laura; Monti, Giorgio

    2016-08-01

    Wireless monitoring could greatly impact the fields of structural health assessment and infrastructure asset management. A common problem to be tackled in wireless networks is the electric power supply, which is typically provided by batteries replaced periodically. A promising remedy for this issue would be to harvest ambient energy. Within this framework, the present paper proposes to harvest ambient-induced vibrations of bridge structures using a new class of piezoelectric textiles. The considered case study is an existing cable-stayed bridge located in Italy along a high-speed road that connects Rome and Naples, for which a recent monitoring campaign has allowed to record the dynamic responses of deck and cables. Vibration measurements have been first elaborated to provide a comprehensive dynamic assessment of this infrastructure. In order to enhance the electric energy that can be converted from ambient vibrations, the considered energy harvester exploits a power generator built using arrays of electrospun piezoelectric nanofibers. A finite element analysis is performed to demonstrate that such power generator is able to provide higher energy levels from recorded dynamic loading time histories than a standard piezoelectric energy harvester. Its feasibility for bridge health monitoring applications is finally discussed.

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

    Science.gov (United States)

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

    2016-04-01

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

  1. Geometrical analysis of Cys-Cys bridges in proteins and their prediction from incomplete structural information

    Science.gov (United States)

    Goldblum, A.; Rein, R.

    1987-01-01

    Analysis of C-alpha atom positions from cysteines involved in disulphide bridges in protein crystals shows that their geometric characteristics are unique with respect to other Cys-Cys, non-bridging pairs. They may be used for predicting disulphide connections in incompletely determined protein structures, such as low resolution crystallography or theoretical folding experiments. The basic unit for analysis and prediction is the 3 x 3 distance matrix for Cx positions of residues (i - 1), Cys(i), (i +1) with (j - 1), Cys(j), (j + 1). In each of its columns, row and diagonal vector--outer distances are larger than the central distance. This analysis is compared with some analytical models.

  2. Smart Pebble: wireless sensors for structural health monitoring of bridge decks

    Science.gov (United States)

    Watters, David G.; Jayaweera, Palitha; Bahr, Alfred J.; Huestis, David L.; Priyantha, Namal; Meline, Robert; Reis, Robert; Parks, Douglas

    2003-08-01

    SRI International is developing a wireless sensor for monitoring the level of chloride ingress into concrete bridge decks. We call this device a Smart Pebble since it has roughly the size and weight of a typical piece of the rock aggregate that is used in such structures. It is "smart" in that it contains a chloride sensor and a radio-frequency identification (RFID) chip that can be queried remotely both to identify it and to indicate chloride concentration levels. The Smart Pebble is also powered remotely, thus precluding the need for any lifetime-limiting batteries. It is designed to be inserted in the bridge deck either during the initial construction (or during refurbishment) or in a back-filled core hole. This paper will discuss the Smart Pebble design, operation, and status.

  3. Structural Performance of Light Weight Multicellular FRP Composite Bridge Deck Using Finite Element Analysis

    Institute of Scientific and Technical Information of China (English)

    Woraphot Prachasaree; Pongsak Sookmanee

    2012-01-01

    Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials,non-corrosiveness and modularization,which should help engineers to obtain more efficient and cost effective structural materials and systems.Currently,FRP composites are becoming more popular in civil engineering applications.The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks (both module and system levels) under various loading conditions through finite element modeling,and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations.The relative deflection,equivalent flexural rigidity,failure load (mode) and load distribution factors (LDF) based on FE results have been compared with experimental data and discussed in detail.The finite element results showing good correlations with experimental data are presented in this work.

  4. 桥梁抗震结构计算%Anti-seismic Structure Calculation of Bridge

    Institute of Scientific and Technical Information of China (English)

    许鹏

    2012-01-01

    依托工程实例,对桥墩进行抗震计算,不仅可以更深入的理解抗震规范,而且定性地总结出利于结构抗震并且经济可行的结构处理方法。%Based on project case,anti-seismic calculation of bridge pier is performed.Therefore,not only can anti-seismic code be understood deeper,but also economic and feasible structure treatment method in favour of structure seismic resistance can be summarized qualitatively.

  5. Synthesis, crystal structure and redox properties of dihydropyrazole-bridged ferrocene-based derivatives

    Science.gov (United States)

    Li, Heng-Dong; Ma, Zai-He; Yang, Kun; Xie, Li-Li; Yuan, Yao-Feng

    2012-09-01

    Dihydropyrazole-bridged ferrocene-based derivatives were prepared by corresponding chalcones with hydrazine hydrate, then acylation with 3-(ethoxycarbonyl)propionyl chloride directly in high yields and purity. All of these compounds were characterized by MS, IR, 1H NMR, 13C NMR and elemental analysis. The relationship between the structure and redox properties was investigated based on the results of single crystal X-ray structure determinations and cyclic voltammetry. The mechanism of the electron transfer for representative compound 4b was verified by density functional theory (DFT) calculations.

  6. Realization of an 850V High Voltage Half Bridge Gate Drive IC with a New NFFP HVI Structure

    Institute of Scientific and Technical Information of China (English)

    Ming Qiao; Hong-Jie Wang; Ming-Wei Duan; Jian Fang; Bo Zhang; Zhao-Ji Li

    2007-01-01

    A NFFP HVI structure which implements high breakdown voltage without using additional FFP and process steps is proposed in this paper. An 850 V high voltage half bridge gate drive IC with the NFFP HVI structure is experimentally realized using a thin epitaxial BCD process. Compared with the MFFP HVI structure,the proposed NFFP HVI structure shows simpler process and lower cost. The high side offset voltage in the half bridge gate drive IC with the NFFP HVI structure is almost as same as that with the selfshielding structure.

  7. Effect of ageing and pulmonary inflammation on the incidence and number of cross-bridging structures in pneumothorax patients

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Tomoaki; Takahashi, Koji; Aburano, Tamio (Dept. of Radiology, Asahikawa Medical Univ., Asahikawa, Hokkaido (Japan)), email: tomoaki3est@gmail.com

    2011-12-15

    Background. There is an improved prognosis for T4 non-small-cell lung cancer in patients who show particular patterns of direct mediastinal invasion. The particular patterns suggest the presence of direct pathways other than the pulmonary hilum between each of the lungs and the mediastinum/chest wall. Purpose. To determine the incidence and number of such direct pathways in pneumothorax patients as well as the factors that affect the development of these pathways. Material and Methods. Two radiologists independently analyzed multidetector computed tomographic images of 81 patients with pneumothorax to assess the incidence and distribution pattern of the cross-bridging structures in the pleural cavity. Results. Cross-bridging structures were observed in the right pneumothorax in 34/54 (63%) patients and in the left pneumothorax in 19/32 (59%) patients. The number of cross-bridging structures was found to be positively correlated with ageing and pulmonary disease. The distribution patterns of cross-bridging structures were found to be specific in formation and often in repeated locations, regardless of the presence of pulmonary disease or the age of the patient. Conclusion. Cross-bridging structures in pneumothoraces were found more frequently in older patients and in patients with pulmonary disease. However, some of the cross-bridging structures may have been congenital because of their specific formations and repeated locations

  8. The Different Methods of Displacement Monitoring at Loading Tests of Bridges or Different Structures

    Directory of Open Access Journals (Sweden)

    Kovačič Boštjan

    2016-01-01

    Full Text Available By measuring the displacements and deformations at different structures we deal in the Faculty of Civil Engineering, transportation Engineering and Architecture in University of Maribor for about 20 years. At that time we measured over 600 structures. Most loading tests of bridges and Viaducts were made. The measurements of movements needed to be as precise and accurate as possible. To do that laboratory test of instruments were made to see which instrument gives us reliable results. Displacements can be determined by geodetic and physical methods, depends of the construction. The use of geodetic methods are still preferable. In the paper the measurements with the total station, the level and rotation level, photogrammetry and solutions on the field by physical methods with inductive transducers are presented. We need to measure displacements as quick as possible but efficiently because we can not repeat the measurements under the same conditions. Also the surveying on the bridge and in the lab with the comparison of methods is presented under the different hard terrain conditions - water beneath the construction, big height of the structure, unapproachability, large span structures.

  9. Small-angle X-ray scattering: a bridge between RNA secondary structures and three-dimensional topological structures

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Xianyang [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., NCI Small Angle X-ray Scattering Core Facility; Stagno, Jason R. [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., Protein-Nucleic Acid Interaction Section, Structural Biophysics Lab.; Bhandari, Yuba R. [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., Protein-Nucleic Acid Interaction Section, Structural Biophysics Lab.; Zuo, Xiaobing [Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Wang, Yun-Xing [National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., NCI Small Angle X-ray Scattering Core Facility; National Inst. of Health (NIH), Bethesda, MD (United States). National Cancer Inst., Protein-Nucleic Acid Interaction Section, Structural Biophysics Lab.

    2015-02-01

    Whereas the structures of small to medium-sized well folded RNA molecules often can be determined by either X-ray crystallography or NMR spectroscopy, obtaining structural information for large RNAs using experimental, computational, or combined approaches remains a major interest and challenge. RNA is very sensitive to small-angle X-ray scattering (SAXS) due to high electron density along phosphate-sugar backbones, whose scattering contribution dominates SAXS intensity. For this reason, SAXS is particularly useful in obtaining global RNA structural information that outlines backbone topologies and, therefore, molecular envelopes. Such information is extremely valuable in bridging the gap between the secondary structures and three-dimensional topological structures of RNAmolecules, particularly those that have proven difficult to study using other structuredetermination methods. Here we review published results of RNA topological structures derived from SAXS data or in combination with other experimental data, as well as details on RNA sample preparation for SAXS experiments.

  10. Implementation and Non-Destructive Evaluation of Composite Structural Shapes in the Tom's Creek Bridge

    OpenAIRE

    Hayes, M. D.; J. Haramis; Lesko, John J.; Cousins, Thomas E.; J.C.Duke; Weyers, Richard E.

    2000-01-01

    A bridge rehabilitation utilizing a hybrid fiber reinforced polymeric composite has been completed in Blacksburg, Virginia. This project involved replacing the superstructure in the Tom's Creek Bridge, a rural short-span traffic bridge with a timber deck and corroded steel girders, with a glue-laminated timber deck on composite girders. In order to verify the bridge design and to address construction issues prior to the rehabilitation, a full-scale mock-up of the bridge was built and tested i...

  11. Diode rectifier bridge-based structure for DFIG-based wind turbine

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2015-01-01

    This paper proposes a new structure for the doubly-fed induction generator (DFIG)-based wind turbine. The proposed structure consists of a DFIG controlled by a partial rated power converter in the rotor side, a three-phase diode rectifier bridge (DRB) connected to the stator, and a DC/AC full rated...... power inverter. As this structure could isolate the DFIG and the grid by a DC-link, the DFIG could avoid the direct influences from the grid, and achieve fault ride through requirement easily. Based on this structure, two control strategies are developed to control the DFIG and fulfill maximum power...... output. The simulation results based a MATALAB/Simulink using a 2MW DFIG compare the performances of DFIG system with the two control strategies. Further, the experimental results based on a scaled-down setup with a 7.5kW DFIG validate the correctness of the control strategies....

  12. Application of Wireless Monitoring System to Structural Health Monitoring of Long-Spanned Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-cheng; QI Xin; Li Qiao

    2007-01-01

    The remote monitoring system applied to the construction control and health monitoring of the Nanjing Third Yangtze River Bridge is introduced. The system makes it possible to get the structure capabilities and environmental parameters of the bridge at the predetermined moment. It sends the collected data over a long distance to an assigned position for display and analysis. The related methods and working condition of the wireless monitoring system are discussed. The measured data during 48 h are employed to determine the feasibility for the closure of the bridge.

  13. Evaluation of ion mobility spectroscopy for determining charge-solvated versus salt-bridge structures of protonated trimers.

    Science.gov (United States)

    Wong, Richard L; Williams, Evan R; Counterman, Anne E; Clemmer, David E

    2005-07-01

    The cross sections of five different protonated trimers consisting of two base molecules and trifluoroacetic acid were measured by using ion mobility spectrometry. The gas-phase basicities of these five base molecules span an 8-kcal/mol range. These cross sections are compared with those determined from candidate low-energy salt-bridge and charge-solvated structures identified by using molecular mechanics calculations using three different force fields: AMBER*, MMFF, and CHARMm. With AMBER*, the charge-solvated structures are all globular and the salt-bridge structures are all linear, whereas with CHARMm, these two forms of the protonated trimers can adopt either shape. Globular structures have smaller cross sections than linear structures. Conclusions about the structure of these protonated trimers are highly dependent on the force field used to generate low-energy candidate structures. With AMBER*, all of the trimers are consistent with salt-bridge structures, whereas with MMFF the measured cross sections are more consistent with charge-solvated structures, although the assignments are ambiguous for two of the protonated trimers. Conclusions based on structures generated by using CHARMm suggest a change in structure from charge-solvated to salt-bridge structures with increasing gas-phase basicity of the constituent bases, a result that is most consistent with structural conclusions based on blackbody infrared radiative dissociation experiments for these protonated trimers and theoretical calculations on the uncharged base-acid pairs.

  14. Nitrogen and oxygen bridged calixaromatics: synthesis, structure, functionalization, and molecular recognition.

    Science.gov (United States)

    Wang, Mei-Xiang

    2012-02-21

    Pedersen, Lehn, and Cram established supramolecular chemistry through their pioneering work with crown ethers, cryptands, and spherands. Since then, the hallmark of supramolecular science has been an increasing sophistication in the design and construction of macrocyclic molecules, as manifested in cyclodextrin derivatives, calixarenes, resorcinarenes, cyclotriveratrylenes, cucurbiturils, calixpyrroles, cyclophanes, and many other examples. Indeed, macrocyclic compounds provide unique models for the study of noncovalent molecular interactions. They also constitute building blocks for constructing high-level molecular and supramolecular architectures and fabricating molecular devices and advanced materials. As a postgraduate in the Huang laboratory in the late 1980s, I became interested in the calix[n]arenes because of their unique conformational structures and versatile complexation properties. The notion of introducing heteroatoms, and particularly nitrogen, into the bridging position of conventional calixarenes was particularly intriguing. Nitrogen, unlike methylene, can adopt either an sp(2) or sp(3) electronic configuration, providing different conjugation systems with adjacent aromatic rings. Consequently, depending on the configuration and conjugation, a range of C-N bond lengths and C-N-C bond angles is possible. The conformation and cavity size in heteroatom-bridged calixarenes might thus be tuned through the bridging heteroatoms and the number of aromatic rings. Furthermore, because heteroatom linkages significantly affect the electron density and distribution on aromatic rings, the electronic features of macrocyclic cavities might be regulated by heteroatoms. Given the essentially limitless combinations possible, only synthetic hurdles would prevent access to numerous diverse heteracalixaromatics. We began a systematic study on nitrogen- and oxygen-bridged calixarenes in 2000, years later than originally envisioned. Before this study, very few

  15. [Bridge employment and retirees' personal well-being. A structural equation model with a European probabilistic sample].

    Science.gov (United States)

    Topa Cantisano, Gabriela; Depolo, Marco; Moriano León, Juan A; Morales Domínguez, José F

    2009-05-01

    The aim of this paper is twofold: first, to examine the relationships between antecedents and consequences of bridge employment activity; second, to analyze the mediator role both of quality and quantity of bridge employment activities in the relationship between antecedents and consequences. First wave panel data from the SHARE (Survey of Health, Ageing and Retirement in Europe) were obtained from 1190 men and women in Europe, using structured interviews and questionnaires. Structural equation modeling analyses, including the sample without missing values (N=650), showed that both quantity and quality of bridge employment participation are predictors of job satisfaction, life satisfaction, and quality of life in retirement. These results validate and expand the previous research on bridge employment activities and partial retirement.

  16. Effect of hardening method and structure of linking bridges on strength of water glass moulding sands

    OpenAIRE

    Stachowicz, M.; K. Granat

    2010-01-01

    The paper presents examination results of the effect of four hardening methods on structure of linking bridges in sandmixes containing hydrated sodium silicate. Test pieces prepared of the moulding sands containing 2.5 % of a binder with molar module between 2.4 and 2.6 were hardened with carbon dioxide, dried traditionally in an oven and hardened with microwaves at 2.54 GHz or using a combination of the CO2 process and microwave heating. It was revealed that the hardening method influences s...

  17. Structural health monitoring approach for detecting ice accretion on bridge cable using the Haar Wavelet Transform

    Science.gov (United States)

    Andre, Julia; Kiremidjian, Anne; Liao, Yizheng; Georgakis, Christos; Rajagopal, Ram

    2016-04-01

    Ice accretion on cables of bridge structures poses serious risk to the structure as well as to vehicular traffic when the ice falls onto the road. Detection of ice formation, quantification of the amount of ice accumulated, and prediction of icefalls will increase the safety and serviceability of the structure. In this paper, an ice accretion detection algorithm is presented based on the Continuous Wavelet Transform (CWT). In the proposed algorithm, the acceleration signals obtained from bridge cables are transformed using wavelet method. The damage sensitive features (DSFs) are defined as a function of the wavelet energy at specific wavelet scales. It is found that as ice accretes on the cables, the mass of cable increases, thus changing the wavelet energies. Hence, the DSFs can be used to track the change of cables mass. To validate the proposed algorithm, we use the data collected from a laboratory experiment conducted at the Technical University of Denmark (DTU). In this experiment, a cable was placed in a wind tunnel as ice volume grew progressively. Several accelerometers were installed at various locations along the testing cable to collect vibration signals.

  18. Probabilistic lifetime performance and structural capacity analysis of continuous reinforced concrete slab bridges

    Science.gov (United States)

    Gao, Zhicheng; Liang, Robert Y.; Patnaik, Anil K.

    2017-09-01

    A reliability-based method was developed for predicting the initiation time and the probability of flexural failure for continuous slab bridges with load-induced cracks exposed to chloride environment resulting from de-icing salts. A practical methodology was used for predicting the diffusion coefficient of chloride ingress into the pre-existing load-induced cracks in concrete. The reduction in the cross-sectional area of the reinforcement due to corrosion was included in the model. The proposed methodology accounts for uncertainties in the strength demand, structural capacity, and corrosion models, as well as uncertainties in environmental conditions, material properties, and structural geometry. All probabilistic data on uncertainties were estimated from the information contained in previous experimental and statistical studies. As an application of the proposed model, a three-span continuous slab bridge in Ohio is presented for demonstration of the developed methodology. A comparison of results clearly shows the importance of considering the effects of the load-induced cracks for correct prediction of the initiation of corrosion time and the critical time to maintain structural integrity.

  19. Analysis of the structure factor of dense krypton gas: Bridge contributions and many-body effects

    Science.gov (United States)

    Aers, G. C.; Dharma-Wardana, M. W. C.

    1984-05-01

    The pair-correlation function g(r) of the Kr-type model fluid with only pair interactions was calculated using the Rosenfeld-Ashcroft modification of the hypernetted-chain (HNC) equation which includes bridge diagrams, and gave results in excellent agreement with Monte Carlo g(r) data. These bridge functions and the known pair potential were used to analyze the neutron-diffraction structure-factor data of Teitsma and Egelstaff, to determine the effective strength of the three-body potential as a function of the density assuming it to be of the Axilrod-Teller (AT) form. The strength of the effective three-body contribution s=ννtheor, where νtheor is the theoretical value, decreases for higher densities, suggesting that the many-body terms (beyond the Axilrod-Teller form) screen the AT interaction as the density increases. The results are very sensitive to the uncertainties in the structure factor S(k) for small k if parameter optimization is used to determine the effective pair potential. However, prediction of the compressibility using s=1 allows us to conclude that νtheor is consistent with the experimental data for low densities, to within the uncertainties in the presently available pair potentials and in the structure-factor data.

  20. NDT evaluation of long-term bond durability of CFRP-structural systems applied to RC highway bridges

    Science.gov (United States)

    Crawford, Kenneth C.

    2016-06-01

    The long-term durability of CFRP structural systems applied to reinforced-concrete (RC) highway bridges is a function of the system bond behavior over time. The sustained structural load performance of strengthened bridges depends on the carbon fiber-reinforced polymer (CFRP) laminates remaining 100 % bonded to concrete bridge members. Periodic testing of the CFRP-concrete bond condition is necessary to sustain load performance. The objective of this paper is to present a non-destructive testing (NDT) method designed to evaluate the bond condition and long-term durability of CFRP laminate (plate) systems applied to RC highway bridges. Using the impact-echo principle, a mobile mechanical device using light impact hammers moving along the length of a bonded CFRP plate produces unique acoustic frequencies which are a function of existing CFRP plate-concrete bond conditions. The purpose of this method is to test and locate CFRP plates de-bonded from bridge structural members to identify associated deterioration in bridge load performance. Laboratory tests of this NDT device on a CFRP plate bonded to concrete with staged voids (de-laminations) produced different frequencies for bonded and de-bonded areas of the plate. The spectra (bands) of frequencies obtained in these tests show a correlation to the CFRP-concrete bond condition and identify bonded and de-bonded areas of the plate. The results of these tests indicate that this NDT impact machine, with design improvements, can potentially provide bridge engineers a means to rapidly evaluate long lengths of CFRP laminates applied to multiple highway bridges within a national transportation infrastructure.

  1. Analysis and assessment of bridge health monitoring mass data—progress in research/development of "Structural Health Monitoring"

    Institute of Scientific and Technical Information of China (English)

    LI AiQun; DING YouLiang; WANG Hao; GUO Tong

    2012-01-01

    The "Structural Health Monitoring" is a project supported by National Natural Science Foundation for Distinguished Young Scholars of China (Grant No.50725828).To meet the urgent requirements of analysis and assessment of mass monitoring data of bridge environmental actions and structural responses,the monitoring of environmental actions and action effect modeling methods,dynamic performance monitoring and early warning methods,condition assessment and operation maintenance methods of key members are systematically studied in close combination with structural characteristics of long-span cable-stayed bridges and suspension bridges.The paper reports the progress of the project as follows.(1) The environmental action modeling methods of long-span bridges are established based on monitoring data of temperature,sustained wind and typhoon.The action effect modeling methods are further developed in combination with the multi-scale baseline finite element modeling method for long-span bridges.(2) The identification methods of global dynamic characteristics and internal forces of cables and hangers for long-span cable-stayed bridges and suspension bridges are proposed using the vibration monitoring data,on the basis of which the condition monitoring and early warning methods of bridges are developed using the environmental-condition-normalization technique.(3) The analysis methods for fatigue loading effect of welded details of steel box girder,temperature and traffic loading effect of expansion joint are presented based on long-term monitoring data of strain and beam-end displacement,on the basis of which the service performance assessment and remaining life prediction methods are developed.

  2. Internet-based collaborative pseudo-dynamic testing of multi-span bridge structure

    Institute of Scientific and Technical Information of China (English)

    Dapeng Wang; Shizhu Tian; Xinjiang Cai; Yunlei Fan; Yan Xiao

    2009-01-01

    In this paper,the first Internet-based collaborative pseudo-dynamic testing of a multi-span bridge system in mainland China is presented in detail,which has been carried out by the collaboration of Hunan University (HNU),Harbin Institute of Technology (HIT) and Tsinghua University (TU) in mainland China,and the University of Southern California (USC) in the USA.The prototype system of Russion River Bridge at Southern California in America is illustrated.Different testing specimens,testing equipments and substructure boundary conditions at HNU and HIT laboratories are described.A network protocol platform for collaborative pseudo-dynamic testing,called NetSLab,and some function modules developed on the use of its standardized interface are introduced.Aiming at the MTS system widely used in structural testing,two approaches are presented to implement the communication interface between NetSLab and testing equipment,respectively,studied by HNU and HIT.The integrated networked testing system and collaborative testing procedures are presented.The testing results manifest that the networked collaborative testing system with powerful capability provides a testing platform with good coordination for complex models or actual structures,and achieves remote sharing of testing equipments.(C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences.Published by Elsevier Limited and Science inChina Press.All rights reserved.

  3. Design and construction of scour protection for deep-water group pile foundation structures of two pylons in the Sutong Bridge project

    Institute of Scientific and Technical Information of China (English)

    He Ping; Guan Yijun; Zhang Xiongwen; Zhang Qun; Zhou Jianhua

    2009-01-01

    Sutong Bridge, as a world-record cable-stayed bridge with its main span exceeding 1 000 m constructed in Yangtze River estuary region in China, is located at a site with complicated hydrologic conditions and poor geotechnical conditions and therefore, scour protection will be a decisive factor for ensuring smooth and successful construction of this bridge. This paper, starting from structural description of deep-water group pile foundation, analyzes impact to the bridge safety introduced by scour and its protection and further presents different solutions of scour protection for foundation structures of this bridge.

  4. Structural Diversity of Metallosupramolecular Assemblies Based on the Bent Bridging Ligand 4,4′-Dithiodipyridine

    Directory of Open Access Journals (Sweden)

    Rüdiger W. Seidel

    2013-05-01

    Full Text Available 4,4′-Dithiodipyridine (dtdp, also termed 4,4′-dipyridyldisulfide, is a bridging ligand of the 4,4′-bipyridine type. The introduction of the disulfide moiety inevitably leads to a relatively rigid angular structure, which exhibits axial chirality. More than 90 metal complexes containing the dtdp ligand have been crystallographically characterised until now. This review focuses on the preparation and structural diversity of discrete and polymeric metallosupramolecular assemblies constructed from dtdp as bridging ligands. These encompass metallamacrocycles with M2L2 topology and coordination polymers with periodicity in one or two dimensions. One-dimensional coordination polymers represent the vast majority of the metallosupramolecular structures obtained from dtdp. These include repeated rhomboids, zigzag, helical and arched chains among other types. In this contribution, we make an attempt to provide a comprehensive account of the structural data that are currently available for metallosupramolecular assemblies based on the bent bridging ligand dtdp.

  5. An autonomous unmanned aerial vehicle sensing system for structural health monitoring of bridges

    Science.gov (United States)

    Reagan, Daniel; Sabato, Alessandro; Niezrecki, Christopher; Yu, Tzuyang; Wilson, Richard

    2016-04-01

    As civil infrastructure (i.e. bridges, railways, and tunnels) continues to age; the frequency and need to perform inspection more quickly on a broader scale increases. Traditional inspection and monitoring techniques (e.g., visual inspection, mechanical sounding, rebound hammer, cover meter, electrical potential measurements, ultrasound, and ground penetrating radar) may produce inconsistent results, require lane closure, are labor intensive and time-consuming. Therefore, new structural health monitoring systems must be developed that are automated, highly accurate, minimally invasive, and cost effective. Three-dimensional (3D) digital image correlation (DIC) systems have the merits of extracting full-field strain, deformation, and geometry profiles. These profiles can then be stitched together to generate a complete integrity map of the area of interest. Concurrently, unmanned aerial vehicles (UAVs) have emerged as valuable resources for positioning sensing equipment where it is either difficult to measure or poses a risk to human safety. UAVs have the capability to expedite the optical-based measurement process, offer increased accessibility, and reduce interference with local traffic. Within this work, an autonomous unmanned aerial vehicle in conjunction with 3D DIC was developed for monitoring bridges. The capabilities of the proposed system are demonstrated in both laboratory measurements and data collected from bridges currently in service. Potential measurement influences from platform instability, rotor vibration and positioning inaccuracy are also studied in a controlled environment. The results of these experiments show that the combination of autonomous flight with 3D DIC and other non-contact measurement systems provides a valuable and effective civil inspection platform.

  6. Novel Wien Bridge Oscillator Design Using Functional Block Structure with Current Conveyors

    Directory of Open Access Journals (Sweden)

    Pavel Brandstetter

    2012-01-01

    Full Text Available The purpose of this paper is to generally present possibilities of the current conveyor use in the well-known active electronic circuits. Current conveyors are able to substitute all known active elements. This claim is supported by the fact, that four basic functional block structures can be realized by use of current conveyors - voltage-controlled voltage source, voltage-controlled current source, current-controlled current source and current-controlled voltage source. The paper presents particular example of use of functional block structure with current conveyors in Wien bridge oscillator, where it successfully substitutes operational amplifier on the place of active element. Both theoretical formulae and design description are given. Finally, OrCAD PSpice simulation results are presented.

  7. Crystal structures and magnetic properties of cyano-bridged 4f-3d complexes

    Institute of Scientific and Technical Information of China (English)

    闫冰; 陈志达

    2001-01-01

    The most recent research progress in the fields of the crystal structure and magnetochemistry for rare earth-transition metal cyano-bridged complexes is reviewed in detail. The emphasis is put on the introduction to the research achievements of our group in this field, including all the types of complexes with different crystal structures in these systems such as dinuclear, trinuclear, one-dimensional chain and hydrogen-bonded network ion-pairs. At the same time a few examples of rare earth-transition metal molecular-based magnets have been found to exhibit excellent magnetochemical properties, such as the long-range magnetic ordering, the higher critical temperature Tc and the stronger coercive force. These results will be expected to promote the research development in this field.

  8. Synthesis, crystal structure and magnetic properties of a one-dimensional copper(II) polymer bridged by different double end-on azide bridges

    Science.gov (United States)

    Zhang, Li-Fang; Yu, Ming-Ming; Ni, Zhong-Hai; Cui, Ai-Li; Kou, Hui-Zhong

    2011-12-01

    A one-dimensional (1D) copper(II) complex [Cu 3(μ 1,1-N 3) 6(dmp) 2] n ( 1) has been synthesized and structurally characterized. The molecular structure of 1 is constructed by trimeric [Cu 3(μ 1,1-N 3) 6(dmp) 2] units formed through two double symmetric (basal-to-basal) end-on (EO) azide bridges and the trimeric units are connected further by double asymmetric (basal-to-apical) EO azide bridges, giving 1D chain-like structure. The chains of 1 are linked together by N-H⋯N azide hydrogen bonds and very weak Cu⋯N azide coordination interactions from μ-1,1,3,3-N 3 fashion to form two-dimensional (2D) supramolecular architecture. The magnetic structure can be considered as uniform 1D chain formed by linear trimeric Cu II-Cu II-Cu II units and the dominating magnetic coupling occurs within the trimeric Cu3II unit. The magnetic study shows that the compound exhibits ferromagnetic interactions with Jt = + 8.36(2) cm -1 and Jc = + 0.35(4) cm -1 for intratrimeric and intertrimeric Cu3II unit based on 1D magnetic model, respectively.

  9. Damage detection in bridge structures under moving loads with phase trajectory change of multi-type vibration measurements

    Science.gov (United States)

    Zhang, Weiwei; Li, Jun; Hao, Hong; Ma, Hongwei

    2017-03-01

    This paper presents a non-model based damage detection approach for bridge structures under moving loads based on the phase trajectory change of multi-type vibration measurements. A brief theoretical background on the vibration of a simply-supported bridge with a crack under moving load is described. The phase trajectories of multi-type dynamic responses are obtained and a damage index is defined as the separated distance between the trajectories of undamaged and damaged structures to indicate the damage location. Numerical studies on a simply-supported beam structure are conducted to investigate the sensitivity and robustness of the proposed approach to accurately identify the damage location. Experimental studies demonstrate that the proposed approach can be used to successfully identify the shear connection failure in a composite bridge model subjected to moving loads.

  10. BRIDGE AS A DOMINATE TECHNICAL STRUCTURE IN THE WRESTLING OF GREEK AND ROMAN AND FREE STYLE

    Directory of Open Access Journals (Sweden)

    Mališa Radović

    2007-05-01

    Full Text Available Wrestling belongs to the group of very complex, semistructual, non-rhytmical sports. Process of achieving the top sport’s results is more and more based on scientifi c methods of researching by discovering an establishing the factors from those the success in sport is depended, and from the other side establishing the effects of sports on structure of person. The objective guarantee in achieving the top of sports results is possible only with maximum connections between sport and factors of persons, as also as discovering the measure instruments which are used to fi nd out the development of these factors. The wrestling is specifi c for differences and many technical elements, strategy, movements of body which use the complex physical capabilities. Including the questionnaire of great sportsmen and trainers, there are opinions which are connected with wrestling bridge as important technical for realization of results. Using the questionnaire paper, we collected the opinions of 218 wrestlers and 98 trainers for Greece -roman and Free Style. These opinions and attitude of sportsmen and trainers give basis for next researching when it is talk about the importance of wrestling bridge

  11. THEORETICAL ASPECTS, EXPERIMENTAL INVESTIGATIONS AND EFFICIENCY IN USAGE OF HIGH-STRENGTH CONCRETE FOR BRIDGE STRUCTURES

    Directory of Open Access Journals (Sweden)

    G. D. Liakhevich

    2014-01-01

    Full Text Available In Belarus concrete with strength up to 60 MPA is used for construction. At the same time high strength concrete with compressive strength above 60 MPA is widely used in all industrially developed countries. High- strength concrete is included in regulatory documents of the European Union and that fact has laid a solid foundation for its application. High strength concrete is produced using highly dispersed silica additives, such as micro-silica and plasticizers (super-plasticizers with a water/cement (w/c ratio not greater than 0.4.Theoretical aspects of high-strength concrete for bridge structures have been studied in the paper. The paper shows a positive impact of highly dispersed additives on structure and physico-mechanical properties of cement compositions, namely: reduction of total porosity of a cement stone in concrete while increasing volumetric concentration and dispersion of a filler; binding of calcium hydroxide with the help of amorphised micro-silica; increased activity of mineral additives during their thin shredding; acceleration of the initial stage of chemical hardening of cement compositions with highly dispersed particle additives that serve as centers of crystallization; “binder-additive” cluster formation due to high surface energy of highly dispersed additive particles; hardening of surface area between a cement stone and aggregates in concrete; high-strength concretes are gaining strength much faster than conventional concretes.Technology of preparation and composition of high-strength concrete using highly dispersed mineral additives and super-plasticizer has been developed in the paper. This concrete will ensure a higher density, wa- ter-and gas tightness, increased resistance to aggressive environment, reduced consumption of concrete and reinforcement, reduced transport and installation weight, increased initial strength, early easing of shutters and preliminary compression, increased length of bridge spans

  12. Aseismic structure of the foundations of super long span bridges; Cho chodai kyoryo no kiso ni motomerareru taishin kozo

    Energy Technology Data Exchange (ETDEWEB)

    Yamagata, M. [Honshu Shikoku Bridge Authority, Kobe (Japan); Tanaka, T. [Oriental Consultants Co. Ltd., Tokyo (Japan)

    1995-09-20

    All the long span bridges that are planned across the straits on the second national expressway, are essential foundations on the deep sea bottom or on the bedrock overlaid with deep sediments, moreover have longer spans than the Akashi Kaikyo Bridge, furthermore are under severe condition that superstructure reaction force is increased with the enlarged spans. Consequently, aseismic stability greatly influences the specifications of the foundations. Although, in a long span bridge foundation like this, it is possible to design and execute on subsequent of same type with Akashi Kaikyo Bridge which is going to execute now, it is evident that the cost of construction increases widely per unit length. In this paper, the concept of an aseismic structure for the foundations of super long span bridges based on the principle of earthquake countermeasures is described. In particular, authors have devised a new type of foundation for the deep sea, named as a `platform`, with a weight about half that of conventional one. The feasibility of this new foundation rests on the surveying, designing and construction technologies acquired from the Akashi Kaikyo Bridge project and on research and development extending over several years. 25 refs., 9 figs., 5 tabs.

  13. Remote sensing of voids in large concrete structures: runways, taxiways, bridges, and building walls and roofs

    Science.gov (United States)

    Weil, Gary J.

    1998-10-01

    Maintenance of our world's infrastructure presents many unique challenges. Engineering and maintenance personnel must maintain around the clock service to millions of people each year while maintaining millions of cubic meters of concrete distributed throughout facilities. This infrastructure includes runways, taxiways, roadways, walkways, bridges, building walls and roofs. Presently only a limited number of accurate and economical techniques exist to test this myriad of concrete structures for integrity and safety as well as insure that they meet original design specifications. Remote sensing, non-destructive testing techniques, such as Infrared Thermography, Ground Penetrating Radar, Magnetometer and Pachometer, measure physical properties affected by the various materials and conditions found within, and under, concrete infrastructure. These techniques have established reputations for accurate investigations of concrete anomalies. This paper will review the applications of different non- destructive testing techniques on many concrete infrastructure components.

  14. Nondestructive testing of airport concrete structures: runways, taxiways, roads, bridges, building walls, and roofs

    Science.gov (United States)

    Weil, Gary J.

    1998-03-01

    Maintenance of airport infrastructure presents many unique challenges. Airport engineering and maintenance personnel must maintain around the clock service to millions of people each year while maintaining millions of cubic meters of concrete distributed throughout the facilities. This infrastructure includes runways, taxiways, roadways, walkways, bridges, building walls and roofs. Presently only a limited number of accurate and economical techniques exist to test this myriad of concrete structures for integrity and safety as well as insure that they meet original design specifications. Remote sensing, non-destructive testing techniques, such as IR thermography, ground penetrating radar, magnetometer and pachometer, measure physical properties affected by the various materials and conditions found within, and under, concrete infrastructure. These techniques have established reputations for accurate investigations of concrete anomalies.

  15. Bridging the pressure gap: Can we get local quantitative structural information at 'near-ambient' pressures?

    Science.gov (United States)

    Woodruff, D. P.

    2016-10-01

    In recent years there have been an increasing number of investigations aimed at 'bridging the pressure gap' between UHV surface science experiments on well-characterised single crystal surfaces and the much higher (ambient and above) pressures relevant to practical catalyst applications. By applying existing photon-in/photon-out methods and developing instrumentation to allow photoelectron emission to be measured in higher-pressure sample environments, it has proved possible to obtain surface compositions and spectroscopic fingerprinting of chemical and molecular states of adsorbed species at pressures up to a few millibars. None of these methods, however, provide quantitative structural information on the local adsorption sites of isolated atomic and molecular adsorbate species under these higher-pressure reaction conditions. Methods for gaining this information are reviewed and evaluated.

  16. Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

    Science.gov (United States)

    Siekierski, Wojciech

    2015-03-01

    At the steel-concrete interface, the horizontal shear forces that are transverse to cross beams occur due to joint action of the steel-concrete composite deck and the truss girders. Numerical analysis showed that values of the forces are big in comparison to the longitudinal shear forces. In both cases extreme force values occur near side edges of a slab. The paper studies possibilities of reduction of these shear forces by structural alterations of the following: rigidity of a concrete slab, arrangement of a wind bracing, arrangement of concrete slab expansion joints. An existing railway truss bridge span has been analysed. Numerical analysis shows that it is possible to reduce the values of shear forces transverse to cross beams. It may reach 20% near the side edges of slabs and 23% in the centre of slab width.

  17. Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

    Directory of Open Access Journals (Sweden)

    Siekierski Wojciech

    2015-03-01

    Full Text Available At the steel-concrete interface, the horizontal shear forces that are transverse to cross beams occur due to joint action of the steel-concrete composite deck and the truss girders. Numerical analysis showed that values of the forces are big in comparison to the longitudinal shear forces. In both cases extreme force values occur near side edges of a slab. The paper studies possibilities of reduction of these shear forces by structural alterations of the following: rigidity of a concrete slab, arrangement of a wind bracing, arrangement of concrete slab expansion joints. An existing railway truss bridge span has been analysed. Numerical analysis shows that it is possible to reduce the values of shear forces transverse to cross beams. It may reach 20% near the side edges of slabs and 23% in the centre of slab width.

  18. Synthesis,characterization,structures and magnetic property of chiral oxalate-bridged dicopper(Ⅱ) complexes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The oxalato-bridged dicopper(II) complexes [Cu2(μ-ox)(LRR)2(H2O)2(ClO4)2] (1),[Cu2(μ-ox)(LRR)2(CH3COCH3)2(ClO4)2](1a),[Cu2(μ-ox)(LSS)2(H2O)2(ClO4)2] (2) and [Cu2(μ-ox)(LRR)(LSS)2(CH3COCH3)2(ClO4)2] (3) [LRR = (8R,10R)-(-)-[4,5]-pineno2,2′-bipyridine,LSS = (8S,10S)-(+)-[4,5]-pineno-2,2′-bipyridine;ox2= oxalate] were first prepared.A possible mechanism for the formation of the chial dicopper(II) complexes was proposed.Based on elemental analysis,conductance measurement,UV-Vis spectra,CD spectra and X-ray single-crystal diffraction,the oxalato-bridged structures of 1 and 2 were deduced to adopt two Cu(II) ions and the bridged oxalate lying in the nearly same plane.The crystal structures of 1a and 3 reveal that the coordination geometry around each Cu(II) ion is an elongated and distorted octahedron and two axial solvent molecules and two perchlorate ions are anti to each other respectively in both binuclear molecules.The solution CD spectra of 1 and 2 in the visible d-d range show very weak Cotton effects with peaks at 588 and 779 nm,which are approximately of mirror image,suggesting the optical activities may be derived from the vicinal effects of the chiragenic centers at the pinene group of LRR and LSS,respectively.Complex 1 has been characterized by variable-temperature magnetic susceptibility and the data was least-square fitted to the Blenaey-Bowers equation.The exchange integral J was found to be -338.41(4) cm-1,indicating a strong antiferromagnetic interaction between two copper(II) ions.

  19. Synthesis, crystal structure and Thermogravimetry of ortho-phthalic acid bridged coordination polymer of Copper(II)

    Indian Academy of Sciences (India)

    BABITA SARMA; SAURAV BHARALI; DIGANTA KUMAR DAS

    2016-06-01

    Coordination polymer of Cu(II) bridged by o-phthalic acid alone is not known. The reaction of$CuCl_{2}.2H_{2}O$ with (2-butoxycarbonyl)benzoic acid yielded three dimensional coordination polymer bridged byo-phthalic acid. X-ray crystal structure shows structure with monoclinic P21/c space group. o-Phthalic acidmolecules act as bridge between two Cu(II), one carboxylate binds to one Cu(II) as bidentate while the othercarboxylate binds to another Cu(II) as monodentate. The four planar co-ordination positions of Cu(II) aresatisfied by two chelated carboxylates while fifth and sixth co-ordination positions are satisfied by monodentatecarboxylates. EPR and TGA of the coordination polymer are also reported.

  20. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations.

    Science.gov (United States)

    Vener, M V; Odinokov, A V; Wehmeyer, C; Sebastiani, D

    2015-06-01

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)-glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898-915 (2011)]. These structures are stabilized by the short (+)N-H⋯O(-) bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm(-1). It is caused by the asymmetric stretching vibrations of the (+)N-H⋯O(-) fragment. Result of the present paper suggests that infrared spectroscopy in the 2000-2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is usually not considered in spectroscopic

  1. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations

    Energy Technology Data Exchange (ETDEWEB)

    Vener, M. V., E-mail: mikhail.vener@gmail.com [Mendeleev University of Chemical Technology, Moscow (Russian Federation); Odinokov, A. V. [Photochemistry Center of the Russian Academy of Sciences, Moscow (Russian Federation); Wehmeyer, C. [Free University, Berlin (Germany); Sebastiani, D. [Martin-Luther-Universität Halle-Wittenberg, Halle (Germany)

    2015-06-07

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)–glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898–915 (2011)]. These structures are stabilized by the short {sup +}N–H⋯O{sup −} bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm{sup −1}. It is caused by the asymmetric stretching vibrations of the {sup +}N–H⋯O{sup −} fragment. Result of the present paper suggests that infrared spectroscopy in the 2000–2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is

  2. The structure and IR signatures of the arginine-glutamate salt bridge. Insights from the classical MD simulations

    Science.gov (United States)

    Vener, M. V.; Odinokov, A. V.; Wehmeyer, C.; Sebastiani, D.

    2015-06-01

    Salt bridges and ionic interactions play an important role in protein stability, protein-protein interactions, and protein folding. Here, we provide the classical MD simulations of the structure and IR signatures of the arginine (Arg)-glutamate (Glu) salt bridge. The Arg-Glu model is based on the infinite polyalanine antiparallel two-stranded β-sheet structure. The 1 μs NPT simulations show that it preferably exists as a salt bridge (a contact ion pair). Bidentate (the end-on and side-on structures) and monodentate (the backside structure) configurations are localized [Donald et al., Proteins 79, 898-915 (2011)]. These structures are stabilized by the short +N-H⋯O- bonds. Their relative stability depends on a force field used in the MD simulations. The side-on structure is the most stable in terms of the OPLS-AA force field. If AMBER ff99SB-ILDN is used, the backside structure is the most stable. Compared with experimental data, simulations using the OPLS all-atom (OPLS-AA) force field describe the stability of the salt bridge structures quite realistically. It decreases in the following order: side-on > end-on > backside. The most stable side-on structure lives several nanoseconds. The less stable backside structure exists a few tenth of a nanosecond. Several short-living species (solvent shared, completely separately solvated ionic groups ion pairs, etc.) are also localized. Their lifetime is a few tens of picoseconds or less. Conformational flexibility of amino acids forming the salt bridge is investigated. The spectral signature of the Arg-Glu salt bridge is the IR-intensive band around 2200 cm-1. It is caused by the asymmetric stretching vibrations of the +N-H⋯O- fragment. Result of the present paper suggests that infrared spectroscopy in the 2000-2800 frequency region may be a rapid and quantitative method for the study of salt bridges in peptides and ionic interactions between proteins. This region is usually not considered in spectroscopic

  3. Rupture Directivity Effect on Seismic Vulnerability of Reinforced Concrete Bridge

    Science.gov (United States)

    Shirazian, Shadi; Nouri, Gholamreza; Ghayamghamian, Mohamadreza

    2017-04-01

    Earthquake catastrophes menace humans` lives and assets. Although earthquakes are inevitable, damage is not. To remedy this situation, significant amount of research is conducted in order to assess the performance of existent man-made structures, particularly infrastructures such as bridges which play a vital role in post earthquake services. The results can be used for assessing retrofit prioritization for structures and as a basis for economic loss estimations. The research presented here determines the vulnerability of a common typical two-span reinforced concrete bridge by generating fragility curves. Near-fault ground motions are different from ordinary ground motions, often containing strong coherent dynamic long-period pulses and permanent ground displacements. Here special attention is given to this type of ground motions, and their effects on the seismic behavior of structure are compared with ordinary motions. The results show near-fault ground motions exacerbate the seismic vulnerability of a bridge by about 68% in comparison with near-field ground motions. In other words, near-source ground motions with forward directivity effect are more dangerous.

  4. Use of Just in Time Maintenance of Reinforced Concrete Bridge Structures based on Real Historical Data Deterioration Models

    Directory of Open Access Journals (Sweden)

    Abu-Tair A.

    2016-01-01

    Full Text Available Concrete is the backbone of any developed economy. Concrete can suffer from a large number of deleterious effects including physical, chemical and biological causes. Large owning bridge structures organizations are facing very serious questions when asking for maintenance budgets. The questions range from needing to justify the need for the work, its urgency, to also have to predict or show the consequences of delayed rehabilitation of a particular structure. There is therefore a need for a probabilistic model that can estimate the range of service lives of bridge populations and also the likelihood of level of deteriorations it can reached for every incremental time interval. A model was developed for such estimation based on statistical data from actual inspection records of a large reinforced concrete bridge portfolio. The method used both deterministic and stochastic methods to predict the service life of a bridge, using these service lives in combination with the just in time (JIT principle of management would enable maintenance managers to justify the need for action and the budgets needed, to intervene at the optimum time in the life of the structure and that of the deterioration. The paper will report on the model which is based on a large database of deterioration records of concrete bridges covering a period of over 60 years and include data from over 400 bridge structures. The paper will also illustrate how the service life model was developed and how these service lives combined with the JIT can be used to effectively allocate resources and use them to keep a major infrastructure asset moving with little disruption to the transport system and its users.

  5. Numerical Modelling of the Dynamic Response of High-Speed Railway Bridges Considering Vehicle-Structure and Structure-Soil-Structure Interaction

    DEFF Research Database (Denmark)

    Bucinskas, Paulius; Agapii, L.; Sneideris, J.

    2015-01-01

    The aim of this paper is the dynamic analysis of a multi-support bridge structure exposed to high-speed railway traffic. The proposed computational model has a unified approach for simultaneously accounting for the bridge structure response, soil response and forces induced by the vehicle...... is idealized as a multi-degree-of-freedom system, modelled with two layers of spring-dashpot suspension systems. Coupling the vehicle system and railway track is realized through interaction forces between the wheels and the rail, where the irregularities of the track are implemented as a random stationary...... stochastic process. The soil body is considered as a layered half-space employing the transfer-matrix methods to obtain the Green's functions in the frequency domain. An iteration procedure is proposed for simultaneously solving the time-domain solution of the multi-degree-of-freedom vehicle affected...

  6. Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

    Science.gov (United States)

    Yang, Caiqian; Wu, Zhishen; Zhang, Yufeng

    2008-06-01

    The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete (PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing, which is characterized by long-gauge length and low cost. The HCFRP sensors were bonded on the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded on the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system. Corrections were made to this article on 13 May 2008. The corrected electronic version is identical to the print version.

  7. Cyanide- and phenoxo-bridged heterobimetallic Fe(III)-Mn(III) complexes: Synthesis, crystal structures and magnetic properties

    Indian Academy of Sciences (India)

    Daopeng Zhang; Ping Wang; Kexun Chen; Xia Chen

    2014-11-01

    By employing two -tricyanidoiron(III) precursors [Ph4P][FeIII(pcq)(CN)3] and [Ph4P][FeIII (pzq)(CN)3] as building blocks and a salen-tpye Schiff-basemanganese (III) compound as assembling segment, two tetranuclear cyanide- and phenoxo- bridged heterobimetallic Fe(III)-Mn(III) complexes {[Mn(saltmen)] [Fe(pcq)(CN)3]}2·2CH3OH (1) and {[Mn(saltmen)] [Fe(pzq)(CN)3]}2·2CH3OH (2) (pcq = 8-(pyridine-2-carboxamido, pzq = 8-(pyrazine-2-carboxamido, saltmen2− = N,N′-(1,1,2,2-tetramethylethylene)bis(salicylideneaminato) dianion) have been synthesized and characterized by elemental analysis, IR spectroscopy and X-ray structure determination. Single x-ray analysis reveals their isostructural cyanide-bridged Fe(III)-Mn(III) binuclear structure. The binuclear entity is self-complementary through phenoxo oxygen from the neighbouring complex, giving cyanide- and phenoxo- bridged tetranuclear structure. Furthermore, under the help of the intermolecular - interaction, these two complexes can be constructed into 1D infinite chain supramolecular structure. Investigation over magnetic susceptibilities reveals the overall ferromagnetic coupling between the adjacent Fe(III) and Mn(III) ions bridged by cyanide group with = 5.34 cm-1 and 5.55 cm-1 for complexes 1 and 2, respectively.

  8. Structural observation of long-span suspension bridges for safety assessment: implementation of an optical displacement measurement system

    Science.gov (United States)

    Lages Martins, L.; Rebordão, J. M.; Silva Ribeiro, A.

    2015-02-01

    This paper addresses the implementation of an optical displacement measurement system in the observation scenario of a long-span suspension bridge and its contribution for structural safety assessment. The metrological background required for quality assurance of the measurements is described, namely, the system's intrinsic parameterization and integration in the SI dimensional traceability chain by calibration, including its measurement uncertainty assessment.

  9. Structural basis for a novel mechanism of DNA bridging and alignment in eukaryotic DSB DNA repair.

    Science.gov (United States)

    Gouge, Jérôme; Rosario, Sandrine; Romain, Félix; Poitevin, Frédéric; Béguin, Pierre; Delarue, Marc

    2015-04-15

    Eukaryotic DNA polymerase mu of the PolX family can promote the association of the two 3'-protruding ends of a DNA double-strand break (DSB) being repaired (DNA synapsis) even in the absence of the core non-homologous end-joining (NHEJ) machinery. Here, we show that terminal deoxynucleotidyltransferase (TdT), a closely related PolX involved in V(D)J recombination, has the same property. We solved its crystal structure with an annealed DNA synapsis containing one micro-homology (MH) base pair and one nascent base pair. This structure reveals how the N-terminal domain and Loop 1 of Tdt cooperate for bridging the two DNA ends, providing a templating base in trans and limiting the MH search region to only two base pairs. A network of ordered water molecules is proposed to assist the incorporation of any nucleotide independently of the in trans templating base. These data are consistent with a recent model that explains the statistics of sequences synthesized in vivo by Tdt based solely on this dinucleotide step. Site-directed mutagenesis and functional tests suggest that this structural model is also valid for Pol mu during NHEJ.

  10. The supramolecular interaction mediated chiral 1D cyanide-bridged metamagnet: synthesis, crystal structures and magnetic properties.

    Science.gov (United States)

    Zhang, Daopeng; Bian, Yongzhong; Qin, Jie; Wang, Ping; Chen, Xia

    2014-01-21

    Two cyanide-bridged enantiopure one-dimensional single chain complexes, [Mn((R,R)-Salcy)Fe(pcq)(CN)3]2n·1.5nDMF (1) and [Mn((S,S)-Salcy)Fe(pcq)(CN)3]2n·1.5nDMF (2), have been synthesized and structurally characterized. Systematically magnetic investigations show the antiferromagnetic coupling between the cyanide-bridged Mn(III)-Fe(III) centers and the interesting metamagnetic behavior at about 5.0 K resulted from the intermolecular π-π interaction.

  11. Effect of Soil-Structure Interaction on Seismic Performance of Long-Span Bridge Tested by Dynamic Substructuring Method

    Directory of Open Access Journals (Sweden)

    Zhenyun Tang

    2017-01-01

    Full Text Available Because of the limitations of testing facilities and techniques, the seismic performance of soil-structure interaction (SSI system can only be tested in a quite small scale model in laboratory. Especially for long-span bridge, a smaller tested model is required when SSI phenomenon is considered in the physical test. The scale effect resulting from the small scale model is always coupled with the dynamic performance, so that the seismic performance of bridge considering SSI effect cannot be uncovered accurately by the traditional testing method. This paper presented the implementation of real-time dynamic substructuring (RTDS, involving the combined use of shake table array and computational engines for the seismic simulation of SSI. In RTDS system, the bridge with soil-foundation system is divided into physical and numerical substructures, in which the bridge is seen as physical substructures and the remaining part is seen as numerical substructures. The interface response between the physical and numerical substructures is imposed by shake table and resulting reaction force is fed back to the computational engine. The unique aspect of the method is to simulate the SSI systems subjected to multisupport excitation in terms of a larger physical model. The substructuring strategy and the control performance associated with the real-time substructuring testing for SSI were performed. And the influence of SSI on a long-span bridge was tested by this novel testing method.

  12. RELATIONSHIP BETWEEN DAMAGE AND CHANGE OF DYNAMIC CHARACTERISTICS IN AN EXISTING BRIDGE FOR VIBRATION-BASED STRUCTURAL HEALTH MONITORING

    Science.gov (United States)

    Miyashita, Takeshi; Tamada, Kazuya; Liu, Cuiping; Iwasaki, Hidenori; Nagai, Masatsugu

    The objective of this study is to understand the relationship between damage and the change of dynamic characteristics in an existing bridge for vibration-based structural health monitoring. Focused bridge is a demolished pedestrian bridge, which is a composite steel girder with two main girders. The first damages are slits by gas cutting, which are given to a lower flange in the lateral direction. Then, outstanding plate in the lower flange is removed along the span. Vibration measurement was carried out in each damage case. As a result, it was confirmed that natural frequencies decreased depending on the progress of damage. Its reduction rate was greater in the modes without torsion. For reproducible analysis, spectral element and finite element analyses were carried out. Analytical results also showed the similar reduction of natural frequencies to measurement.

  13. A Multiscale Finite Element Model Validation Method of Composite Cable-Stayed Bridge Based on Structural Health Monitoring System

    Directory of Open Access Journals (Sweden)

    Rumian Zhong

    2015-01-01

    Full Text Available A two-step response surface method for multiscale finite element model (FEM updating and validation is presented with respect to Guanhe Bridge, a composite cable-stayed bridge in the National Highway number G15, in China. Firstly, the state equations of both multiscale and single-scale FEM are established based on the basic equation in structural dynamic mechanics to update the multiscale coupling parameters and structural parameters. Secondly, based on the measured data from the structural health monitoring (SHM system, a Monte Carlo simulation is employed to analyze the uncertainty quantification and transmission, where the uncertainties of the multiscale FEM and measured data were considered. The results indicate that the relative errors between the calculated and measured frequencies are less than 2%, and the overlap ratio indexes of each modal frequency are larger than 80% without the average absolute value of relative errors. These demonstrate that the proposed method can be applied to validate the multiscale FEM, and the validated FEM can reflect the current conditions of the real bridge; thus it can be used as the basis for bridge health monitoring, damage prognosis (DP, and safety prognosis (SP.

  14. Regulation of the Dynamic Live Load Factor for Calculation of Bridge Structures on High-Speed Railway Mainlines

    Science.gov (United States)

    Dyachenko, Leonid K.; Benin, Andrey V.

    2017-06-01

    When the high-speed railway traffic is being organized, it becomes necessary to elaborate bridge design standards for high-speed railways (HSR). Methodology of studying the issues of HSR bridge design is based on the comprehensive analysis of domestic research as well as international experience in design, construction and operation of high-speed railways. Serious requirements are imposed on the HSR artificial structures, which raise a number of scientific tasks associated mainly with the issues of the dynamic interaction of the rolling stock and the bridge elements. To ensure safety of traffic and reliability of bridges during the whole period of operation one needs to resolve the dynamic problems of various types of high-speed trains moving along the structures. The article analyses dependences of the magnitude of inertial response on the external stress parameters and proposes a simplified method of determination of the dynamic live load factor caused by the passage of high-speed trains. The usefulness of the given research arises from the reduction of complexity of the complicated dynamic calculations needed to describe a high-speed train travelling along the artificial structures.

  15. Fatigue crack identification and lifetime prediction for steel bridge deck structures

    NARCIS (Netherlands)

    Pahlavan, P.L.; Pijpers, R.J.M.; Hakkesteegt, H.C.; Jansen, T.H.; Peelen, W.H.A.

    2015-01-01

    Fatigue, as the governing degradation mechanism in steel bridge decks, can lead to non-inspectable cracks under the welded intersections of stiffeners to the deck plate. As a result, estimation of the remaining service life and optimization of the maintenance program of steel bridge decks become a g

  16. Fabrication of Monolithic Bridge Structures by Vacuum-Assisted Capillary-Force Lithography

    KAUST Repository

    Kwak, Rhokyun

    2009-04-06

    Monolithic bridge structures were fabricated by using capillary-force lithography (CFL), which was developed for patterning polymers over a large area by combining essential features of nanoimprint lithography and capillarity. A patterned soft mold was placed on a spin-coated UV-curable resin on a substrate. The polymer then moved into the cavity of the mold by capillary action and then solidified after exposure to UV radiation. The uncured resin was forced to migrate into the cavity of a micropatterned PDMS mold by capillarity, and then exposed to UV radiation under a high-energy mercury lamp with intensity. A rotary pump was then turned on, decreasing the air pressure in the chamber. SEM images were taken with a high-resolution SEM at an acceleration voltage greater than 15 kV. It was observed that when the air pressure was rapidly reduced to a low vacuum, the top layer moved into the nanochannels with a meniscus at the interface between the nanoscale PUA and the base structure.

  17. Functional mutagenesis screens reveal the 'cap structure' formation in disulfide-bridge free TASK channels.

    Science.gov (United States)

    Goldstein, Matthias; Rinné, Susanne; Kiper, Aytug K; Ramírez, David; Netter, Michael F; Bustos, Daniel; Ortiz-Bonnin, Beatriz; González, Wendy; Decher, Niels

    2016-01-22

    Two-pore-domain potassium (K2P) channels have a large extracellular cap structure formed by two M1-P1 linkers, containing a cysteine for dimerization. However, this cysteine is not present in the TASK-1/3/5 subfamily. The functional role of the cap is poorly understood and it remained unclear whether K2P channels assemble in the domain-swapped orientation or not. Functional alanine-mutagenesis screens of TASK-1 and TRAAK were used to build an in silico model of the TASK-1 cap. According to our data the cap structure of disulfide-bridge free TASK channels is similar to that of other K2P channels and is most likely assembled in the domain-swapped orientation. As the conserved cysteine is not essential for functional expression of all K2P channels tested, we propose that hydrophobic residues at the inner leaflets of the cap domains can interact with each other and that this way of stabilizing the cap is most likely conserved among K2P channels.

  18. Exploring New Boundaries to Mitigate Structural Vibrations of Bridges in Seismic Regions: A Smart Passive Strategy

    Directory of Open Access Journals (Sweden)

    Giuseppe Maddaloni

    2016-01-01

    Full Text Available The combined use of two emerging technologies in the field of seismic engineering is investigated. The first is a semiactive control, to reduce smartly the effects induced by earthquakes on structures. The second is the Seismic Early Warning System which allows an estimate of the Peak Ground Accelerations of an incoming earthquake. This paper proposes the exploitation of this information in the framework of a semiactive control strategy based on the use of magnetorheological (MR dampers. The main idea consists of changing the MR dampers’ behaviour by the PGA estimated by the SEWS, to obtain the optimal seismic response of the structure. The control algorithm needed to drive the variable devices, according to the PGA estimate, is the core issue of the proposed strategy. It has been found that different characteristics of earthquakes that occur at different sites play a significant role in the definition of a control algorithm. Therefore, a design procedure for “regional” control algorithms has been performed. It is based on the results of several nonlinear dynamic simulations performed using natural earthquakes and on the use of a multicriteria decision-making procedure. The effectiveness of the proposed control strategy has been verified with reference to a highway bridge and to two specific worldwide seismic regions.

  19. Establishment and Application of the Wind and Structural Health Monitoring System for the Runyang Yangtze River Bridge

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available Structural health monitoring can provide a practical platform for detecting the evolution of structural damage or performance deterioration of engineering structures. The final objective is to provide reasonable suggestions for structural maintenance and management and therefore ensure the structural safety according to the real-time recorded data. In this paper, the establishment of the wind and structural health monitoring system (WSHMS implemented on the Runyang Yangtze River Bridge (RYRB in China is introduced. The composition and functions of the WSHMS are presented. Thereinto, the sensory subsystem utilized to measure the input actions and structural output responses is introduced. And the core functions of the data management and analysis subsystem (DMAS including model updating, structural condition identification, and structural condition assessment are illustrated in detail. A three-stage strategy is applied into the FE model updating of RYRB, and a two-phase strategy is proposed to adapt to structural health diagnosis and damage identification. Considering the structural integral security and the fatigue characteristic of steel material, the condition assessment of RYRB is divided into structural reliability assessment and structural fatigue assessment, which are equipped with specific and elaborate module for effective operation. This research can provide references for the establishment of the similar structural health monitoring systems on other cable-supported bridges.

  20. SUSPNDRS: a numerical simulation tool for the nonlinear transient analysis of cable support bridge structures, part 1: theoretical development

    Energy Technology Data Exchange (ETDEWEB)

    McCallen, D.; Astaneh-Asl, A. [California Univ., Berkeley, CA (United States)

    1997-06-01

    The work reprint on herein was aimed at developing methodologies and tools for efficient and accurate numerical simulation of the seismic response of suspension and cable-stayed structures. A special purpose finite element program has been constructed and the underlying theory and demonstration example problems are presented. A companion report [Ref 1] discusses the application of this technology for a major suspension bridge structure.

  1. Bridging scales from satellite to grains: Structural mapping aided by tablet and photogrammetry

    Science.gov (United States)

    Hawemann, Friedrich; Mancktelow, Neil; Pennacchioni, Giorgio; Wex, Sebastian; Camacho, Alfredo

    2016-04-01

    Bridging scales from satellite to grains: Structural mapping aided by tablet and photogrammetry A fundamental problem in small-scale mapping is linking outcrop observations to the large scale deformation pattern. The evolution of handheld devices such as tablets with integrated GPS and the availability of airborne imagery allows a precise localization of outcrops. Detailed structural geometries can be analyzed through ortho-rectified photo mosaics generated by photogrammetry software. In this study, we use a cheap standard Samsung-tablet (individual, up to 60 m long shear zones with the tracking option offered by the program Locus Map. Even though GPS accuracy is about 3 m, the relative error from one point to another during tracking is on the order of only about 1 dm. Parts of the shear zone with excellent outcrop are photographed with a standard camera with a relatively wide angle in a mosaic array. An area of about 30 sqm needs about 50 photographs with enough overlap to be used for photogrammetry. The software PhotoScan from Agisoft matches the photographs in a fully automated manner, calculates a 3D model of the outcrop, and has the option to project this as an orthophoto onto a flat surface. This allows original orientations of grain-scale structures to be recorded over areas on a scale up to tens to hundreds of metres. The photo mosaics can then be georeferenced with the aid of the GPS-tracks of the shear zones and included in a GIS. This provides a cheap recording of the structures in high detail. The great advantages over mapping with UAVs (drones) is the resolution (1cm), the independence from weather and energy source, and the low cost.

  2. A study on building an experimental system of PVDF sensor for structural local monitoring on a bridge model

    Science.gov (United States)

    Yu, Yan; Wang, Yang; An, Yonghui; Ou, Jinping

    2010-04-01

    Smart material structure originated from aerospace area has been a research hotspot in the application of civil engineering, shipping, and so on. For structural health monitoring of civil engineering, the research about highperformance sensing unit of smart material structure is very important, and this will possibly push further the development of health monitoring and diagnosis technique. As one of the piezoelectric materials belonging to smart materials, PVDF (Polyvinylidene Fluoride) film is widely concerned for its property advantages of low cost, good mechanical ability, high sensibility, resistance of corrosion. In this paper, for the validation of using PVDF for sensing unit for structural local monitoring of civil engineering, an experimental system of PVDF sensor for structural local monitoring on a bridge model is built. Based on the operating mechanism of PVDF, its measure circuit and characteristics(quasi-static and dynamic strain responding) are introduced. A bridge model is designed, and experiments have also been done for structural local health monitoring using PVDF. The experimental results show that, PVDF can finish impact response monitoring and damage detection of a bridge model, and the developed experimental system with simple and easy implement can be used for practical monitoring engineering.

  3. Introduction of structural health and safety monitoring warning systems for Shenzhen-Hong Kong Western Corridor Shenzhen Bay Bridge

    Science.gov (United States)

    Li, N.; Zhang, X. Y.; Zhou, X. T.; Leng, J.; Liang, Z.; Zheng, C.; Sun, X. F.

    2008-03-01

    Though the brief introduction of the completed structural health and safety monitoring warning systems for Shenzhen-Hongkong western corridor Shenzhen bay highway bridge (SZBHMS), the self-developed system frame, hardware and software scheme of this practical research project are systematically discussed in this paper. The data acquisition and transmission hardware and the basic software based on the NI (National Instruments) Company virtual instruments technology were selected in this system, which adopted GPS time service receiver technology and so on. The objectives are to establish the structural safety monitoring and status evaluation system to monitor the structural responses and working conditions in real time and to analyze the structural working statue using information obtained from the measured data. It will be also provided the scientific decision-making bases for the bridge management and maintenance. Potential technical approaches to the structural safety warning systems, status identification and evaluation method are presented. The result indicated that the performance of the system has achieved the desired objectives, ensure the longterm high reliability, real time concurrence and advanced technology of SZBHMS. The innovate achievement which is the first time to implement in domestic, provide the reference for long-span bridge structural health and safety monitoring warning systems design.

  4. Systematic study of the structures of potassiated tertiary amino acids: salt bridge structures dominate

    NARCIS (Netherlands)

    Drayß, M.K.; Blunk, D.; Oomens, J.; Gao, B.; Wyttenbach, T.; Bowers, M.T.; Schäfer, M.

    2009-01-01

    The gas-phase structures of a series of potassiated tertiary amino acids have been systematically investigated using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser, ion mobility spectrometry (IMS), and computational modeling. The examine

  5. Systematic Study of the Structures of Potassiated Tertiary Amino Acids: Salt Bridge Structures Dominate

    NARCIS (Netherlands)

    Drayss, M. K.; Blunk, D.; Oomens, J.; Gao, B.; Wyttenbach, T.; Bowers, M. T.; Schafer, M.

    2009-01-01

    The gas-phase structures of a series of potassiated tertiary amino acids have been systematically investigated using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser, ion mobility spectrometry (IMS), and computational modeling. The examine

  6. Newly developed high performance structural steels for long span bridge construction; Chotaikyo ni shiyosareru shinkozai

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Y. [Nippon Steel Corp., Tokyo (Japan)

    1998-11-15

    This paper reports new steels for long span bridge construction with the thick steel plate as a main part. On the basis of the high-tension steel utilizing technology examined around 1965, a reheated, quenched-and-tempered martensitic steel plate (HT690) was used for the Onaruto Bridge and Seto Ohashi Bridge in a Honsyu-Shikoku linking project. Moreover, a larger number of quenched martensitic high-tension steel plates (HT670 and HT780) were used for the Yojima Bridge together with existing SM400, SM490, SM520, and SM570 steel plates. The lately built Akashi Kaikyo Ohashi Bridge that is 1990 m between struts is longest in the world. The newly developed steel plate (HT780) for a bridge girder of which weldability was improved for lightening was used actually. To reduce the welding cost or improve the welding environment, this steel plate decreased the preheating temperature for weld cracking prevention in a heat-affected zone from about 100degC to 50degC or less. A new wire (of 1800Mpa in tensile strength) was also used for a cable. In future, the bridge girder will be economically and rationally manufactured by the development of design and construction methods that fully draw the characteristics of the new steel. 33 refs., 9 figs., 2 tabs.

  7. Photochromic Mechanism of a Bridged Diarylethene: Combined Electronic Structure Calculations and Nonadiabatic Dynamics Simulations.

    Science.gov (United States)

    Wang, Ya-Ting; Gao, Yuan-Jun; Wang, Qian; Cui, Ganglong

    2017-02-02

    Intramolecularly bridged diarylethenes exhibit improved photocyclization quantum yields because the anti-syn isomerization that originally suppresses photocyclization in classical diarylethenes is blocked. Experimentally, three possible channels have been proposed to interpret experimental observation, but many details of photochromic mechanism remain ambiguous. In this work we have employed a series of electronic structure methods (OM2/MRCI, DFT, TDDFT, RI-CC2, DFT/MRCI, and CASPT2) to comprehensively study excited state properties, photocyclization, and photoreversion dynamics of 1,2-dicyano[2,2]metacyclophan-1-ene. On the basis of optimized stationary points and minimum-energy conical intersections, we have refined experimentally proposed photochromic mechanism. Only an S1/S0 minimum-energy conical intersection is located; thus, we can exclude the third channel experimentally proposed. In addition, we find that both photocyclization and photoreversion processes use the same S1/S0 conical intersection to decay the S1 system to the S0 state, so we can unify the remaining two channels into one. These new insights are verified by our OM2/MRCI nonadiabatic dynamics simulations. The S1 excited-state lifetimes of photocyclization and photoreversion are estimated to be 349 and 453 fs, respectively, which are close to experimentally measured values: 240 ± 60 and 250 fs in acetonitrile solution. The present study not only interprets experimental observations and refines previously proposed mechanism but also provides new physical insights that are valuable for future experiments.

  8. Synthesis, structure characterization, and anticancer activity of a novel oxygen-bridged tricyclic Biginelli adduct

    Science.gov (United States)

    Ibrahim, Mohamed M.; El-Sheshtawy, Hamdy S.; El-Kemary, Maged; Al-Juaid, Salih; Youssef, Mohamed; El-Azab, Islam H.

    2017-06-01

    Herein, we report the one-pot cyclization of Biginelli Adduct, ethyl 4-(2-hydroxyphenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (I) to the oxygen-bridged adduct, ethyl 2-methyl-4-thioxo-3,4,5,6-tetrahydro-2H-2,6-methanobenzo[g] [1,3,5]oxadiazocine-11-carboxylate (II) in a high yield and purity under mild reaction condition using zinc(II) perchlorate hexahydrate as a highly efficient catalyst. The cyclic product (II) was characterized both in the solid state and in solution using FT-IR, 1H NMR, and UV-visible spectroscopy. Theoretical calculations using density functional theory with B3LYP/6-311++G(d,p) level were used to further investigate the structure properties. DFT calculations (gas phase) revealed the stability of cyclic compound II (3.45 kcal/mol) than compound I. In addition, the anticancer activity of II was investigated using MCF-7 human breast cell line. The results revealed a moderate activity with 223.55 μg/ml IC50 value.

  9. Boron-Boron One-Electron Sigma Bonds versus B-X-B Bridged Structures.

    Science.gov (United States)

    Kusevska, Elena; Montero-Campillo, M Merced; Mó, Otilia; Yáñez, Manuel

    2016-09-12

    The existence of one-electron B-B σ bonds, for two different sets of compounds, was investigated by analyzing their electron density with different tools, namely QTAIM, ELF, NCIPLOT, and NBO approaches. Our results indicate that although the generic label "one-electron sigma bond" is often used in the literature, the nature of these bonds varies considerably, or they even do not exist. The [B2 X6 ](-) radical anions give place to true covalent one-electron σ bonds, the stronger the more electronegative is the X substituent. When both boron atoms are substituents in a rigid aromatic moiety, such as naphthalene, to yield 1,8-disubstituted derivatives, two kinds of equilibrium structures are found, those also stabilized through a one-electron σ bond (X=OH, F, Cl, CN) and those stabilized by the formation of B-X-B bridges (X=H, OMe). These 1,8-BX2 naphthalene derivatives can be considered as analogues of 1,8-NX2 naphthalene proton sponges. While the latter are able to stabilize a proton between the two basic sites, the former are able to stabilize an electron between the two electron-deficient B atoms. Interestingly, when all the H atoms attached to B are substituted by phenyl groups no one-electron σ bonds B-B bonds are formed, due to the dispersion of the unpaired electron in the aromatic substituents.

  10. Structural health monitoring system for bridges based on skin-like sensor

    Science.gov (United States)

    Loupos, Konstantinos; Damigos, Yannis; Amditis, Angelos; Gerhard, Reimund; Rychkov, Dmitry; Wirges, Werner; Schulze, Manuel; Lenas, Sotiris-Angelos; Chatziandreoglou, Christos; Malliou, Christina M.; Tsaoussidis, Vassilis; Brady, Ken; Frankenstein, Bernd

    2017-09-01

    Structural health monitoring activities are of primal importance for managing transport infrastructure, however most SHM methodologies are based on point-based sensors that have limitations in terms of their spatial positioning requirements, cost of development and measurement range. This paper describes the progress on the SENSKIN EC project whose objective is to develop a dielectric-elastomer and micro-electronics-based sensor, formed from a large highly extensible capacitance sensing membrane supported by advanced microelectronic circuitry, for monitoring transport infrastructure bridges. Such a sensor could provide spatial measurements of strain in excess of 10%. The actual sensor along with the data acquisition module, the communication module and power electronics are all integrated into a compact unit, the SENSKIN device, which is energy-efficient, requires simple signal processing and it is easy to install over various surface types. In terms of communication, SENSKIN devices interact with each other to form the SENSKIN system; a fully distributed and autonomous wireless sensor network that is able to self-monitor. SENSKIN system utilizes Delay-/Disruption-Tolerant Networking technologies to ensure that the strain measurements will be received by the base station even under extreme conditions where normal communications are disrupted. This paper describes the architecture of the SENSKIN system and the development and testing of the first SENSKIN prototype sensor, the data acquisition system, and the communication system.

  11. TECHNOLOGY AND EFFICIENT USE OF PEAT ASH IN MASTICS FOR WATERPROOFING OF BRIDGE AND TUNNEL STRUCTURES

    Directory of Open Access Journals (Sweden)

    G. D. Lyahevich

    2015-01-01

    Full Text Available A prospective method for protection of  bridges and tunnels against aggressive water action is surface waterproofing on the basis of an organo-mineral binder. Its structural strength can be increased by introduction of particles which are similar to the size of  asphaltenes and an elasticity of disperse medium has been increased due to introduction of polymers. These theoretical suppositions point out the possibility for simultaneous provision of flexibility at low temperatures and high heat resistance for mastics on the basis  of organo-mineral binders. In this regard a goal has been set to obtain a mastic high flexibility and high heat resistance  while using finely divided activated peat ash.Rubber crushed in accordance with ТУ (Technical Specifications 38.108035–87,  divinyl-styrene thermoelastoplast DСT-30Р-20ПС,  bitumen of grade 20/30 in accordance with СТБ ЕН 12591–2010, ash from burning peat at the Lida Peat Briquette Plant, multi-purpose industrial oil of solvent refining with high viscosity index, super-plasticizer – sodium salt which is a condensation product of aromatic carbon sulfo-oxidation with formaldehyde and neutralization with the help of sodium hydroxide (type 1 have been used in order to obtain the stated objective. While using these materials compositions and technology for preparation of organo-mineral mastics have been developed in the paper. Their tests have shown that a modification of finely divided  mastics carried out with the help of peat ash which is activated by super-plasticizer НСПКСАУсФ-1, various polymer additives, contributes to an increase in their heat resistance, elasticity, water resistance, and also allows to control their technological and operational characteristics. The paper has experimentally confirmed that peat ash can be successfully used for preparation of high-quality waterproofing mastics which are so necessary for  protection of bridge and tunnel

  12. Some studies on structural planning of long-span cable stayed bridge; Choshikan shachokyo no kozo keikaku ni kansuru 2,3 no kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Endo, T. [NKK Corp., Tokyo (Japan)

    1997-06-20

    Feasibility of cabled-stayed bridges with 1000m-grade spans is discussed while re-examining the plan for constructing a Great Tatara Bridge to connect Honshu and Shikoku, Japan, and in this process various tasks and questions are isolated. Some which will be problems in designing the new bridge structure are taken up, including the load-bearing capability of the bridge as a whole, vibration of long cables, resistance to long-period earthquakes, and accuracy management during the construction work. Findings are stated below. A cable-stayed bridge is not significantly different from a suspension bridge and is sufficiently feasible until the span exceeds 1500m. When the span is longer, however, the bridge beam cross section needs be designed very prudently in view of the great axial force and wind load to be imposed on it. Effective for the assurance of load-bearing capability for a long-span cabled-stayed bridge is a structure in which load is elastically confined in the direction of the bridge axis. In connection with vibration damping for very long cables, it is verified that a new dimpled cable suits the purpose of suppressing wind load from increasing without reduction in damping effect. 28 refs., 23 figs., 7 tabs.

  13. Double-bridge bonding of aluminium and hydrogen in the crystal structure of gamma-AlH3.

    Science.gov (United States)

    Yartys, Volodymyr A; Denys, Roman V; Maehlen, Jan Petter; Frommen, Christoph; Fichtner, Maximilian; Bulychev, Boris M; Emerich, Hermann

    2007-02-19

    Aluminum trihydride (alane) is one of the most promising among the prospective solid hydrogen-storage materials, with a high gravimetric and volumetric density of hydrogen. In the present work, the alane, crystallizing in the gamma-AlH3 polymorphic modification, was synthesized and then structurally characterized by means of synchrotron X-ray powder diffraction. This study revealed that gamma-AlH3 crystallizes with an orthorhombic unit cell (space group Pnnm, a = 5.3806(1) A, b = 7.3555(2) A, c = 5.77509(5) A). The crystal structure of gamma-AlH3 contains two types of AlH6 octahedra as the building blocks. The Al-H bond distances in the structure vary in the range of 1.66-1.79 A. A prominent feature of the crystal structure is the formation of the bifurcated double-bridge bonds, Al-2H-Al, in addition to the normal bridge bonds, Al-H-Al. This former feature has not been previously reported for Al-containing hydrides so far. The geometry of the double-bridge bond shows formation of short Al-Al (2.606 A) and Al-H (1.68-1.70 A) bonds compared to the Al-Al distances in Al metal (2.86 A) and Al-H distances for Al atoms involved in the formation of normal bridge bonds (1.769-1.784 A). The crystal structure of gamma-AlH3 contains large cavities between the AlH6 octahedra. As a consequence, the density is 11% less than for alpha-AlH3.

  14. Structure-borne noise of railway composite bridge: Numerical simulation and experimental validation

    Science.gov (United States)

    Li, Xiaozhen; Liu, Quanmin; Pei, Shiling; Song, Lizhong; Zhang, Xun

    2015-09-01

    In order to investigate the characteristics of the noise from steel-concrete composite bridges under high-speed train loading, a model used to predict the bridge-borne noise is established and validated through a field experiment. The numerical model for noise prediction is developed based on the combination of spatial train-track-bridge coupled vibration theory and Statistical Energy Analysis (SEA). Firstly, train-track-bridge coupled vibration is adopted to obtain the velocity time history of the bridge deck vibration. Then, the velocity time history is transferred into frequency domain through FFT to serve as the vibratory energy of SEA deck subsystems. Finally, the transmission of the vibratory energy is obtained by solving the energy balance equations of SEA, and the sound radiation is computed using the vibro-acoustic theory. The numerically computed noise level is verified by a field measurement. It is determined that the dominant frequency of steel-concrete composite bridge-borne noise is 20-1000 Hz. The noise from the bottom flange of steel longitudinal girder is less than other components in the whole frequency bands, while the noise from web of steel longitudinal girder is dominant in high frequency range above 315 Hz. The noise from concrete deck dominates in low-frequency domain ranges from 80 Hz to 160 Hz.

  15. LINKING LUNG AIRWAY STRUCTURE TO PULMONARY FUNCTION VIA COMPOSITE BRIDGE REGRESSION

    Science.gov (United States)

    Chen, Kun; Hoffman, Eric A.; Seetharaman, Indu; Jiao, Feiran; Lin, Ching-Long; Chan, Kung-Sik

    2017-01-01

    The human lung airway is a complex inverted tree-like structure. Detailed airway measurements can be extracted from MDCT-scanned lung images, such as segmental wall thickness, airway diameter, parent-child branch angles, etc. The wealth of lung airway data provides a unique opportunity for advancing our understanding of the fundamental structure-function relationships within the lung. An important problem is to construct and identify important lung airway features in normal subjects and connect these to standardized pulmonary function test results such as FEV1%. Among other things, the problem is complicated by the fact that a particular airway feature may be an important (relevant) predictor only when it pertains to segments of certain generations. Thus, the key is an efficient, consistent method for simultaneously conducting group selection (lung airway feature types) and within-group variable selection (airway generations), i.e., bi-level selection. Here we streamline a comprehensive procedure to process the lung airway data via imputation, normalization, transformation and groupwise principal component analysis, and then adopt a new composite penalized regression approach for conducting bi-level feature selection. As a prototype of composite penalization, the proposed composite bridge regression method is shown to admit an efficient algorithm, enjoy bi-level oracle properties, and outperform several existing methods. We analyze the MDCT lung image data from a cohort of 132 subjects with normal lung function. Our results show that, lung function in terms of FEV1% is promoted by having a less dense and more homogeneous lung comprising an airway whose segments enjoy more heterogeneity in wall thicknesses, larger mean diameters, lumen areas and branch angles. These data hold the potential of defining more accurately the “normal” subject population with borderline atypical lung functions that are clearly influenced by many genetic and environmental factors.

  16. One and Two-dimensional Structures of a New Oxamido Copper(Ⅱ) Complex with Phthalato Bridged

    Institute of Scientific and Technical Information of China (English)

    CHEN Jing; JIANG Zong-Hui; LIAO Dai-Zheng; YAN Shi-Ping

    2005-01-01

    A new o-phthalato-bridged oxamide copper(Ⅱ) complex 1, {[Cu2(oxap)](pht)4H2O}n (oxap = N, N'-bis(2-aminopropyl)oxamide, pht = phthalate dianion), has been prepared and structurally characterized. It crystallizes in monoclinic, space group C2/c with a = 23.424(4), b = 7.9696(14), c = 15.727(3) (A), β = 129.617(2)°, C16H28Cu2N4O10, Mr = 563.50, V = 2261.6(7) (A)3, Z = 4, Dc = 1.655 g/cm3,μ(MoKα) = 1.939 mm 1, F(000) = 1160, the final R = 0.0393 and wR = 0.0928 for 1707 observed reflections with I > 2σ(Ⅰ). Single-crystal X-ray analysis reveals that 1 displays a one-dimensional zigzag chain structure, in which each Cu(oxap) moiety adopting trans-conformation is connected by μ1,6-phthalate anion bridges, and these zigzag chains are further linked by anotherμ1,6-phthalate anion bridge to form a 2D sheet structure. The polar guest water molecules reside in the inter- and intrasheets to stabilize the whole crystal structure.

  17. Long-term monitoring of a PSC box girder bridge: Operational modal analysis, data normalization and structural modification assessment

    Science.gov (United States)

    Cury, Alexandre; Cremona, Christian; Dumoulin, John

    2012-11-01

    For reliable performance of vibration-based damage detection algorithms, it is important to distinguish abnormal changes in modal parameters caused by structural damage from normal changes due to environmental fluctuations. This paper firstly addresses the modeling of temperature effects on modal frequencies of a PSC box girder bridge located on the A1 motorway in France. Based on a six-month monitoring experimental program, modal frequencies of the first seven mode shapes and temperatures have been measured at three hour intervals. Neural networks are then introduced to formulate regression models for quantifying the effect of temperature on modal parameters (frequencies and mode shapes). In 2009, this bridge underwent a strengthening procedure. In order to assess the effect of strengthening on the vibration characteristics of the bridge, modal properties had to be corrected from temperature influence. Thus, the first goal is to assess the changes on the vibration signature of this bridge induced by the strengthening. For this purpose, classical statistical analysis and clustering methods are applied to the data recorded over the period after strengthening. The second goal is to evaluate the influence of temperature effects on the clustering results. It comes that the temperature correction significantly improves the confidence in the novelty detection and in the strengthening efficiency.

  18. Bridge Crossing Simulator

    Science.gov (United States)

    2014-10-07

    Requirement BCS Computer-controlled hydraulic actuation system to impart simulated crossing loads on an entire bridge structure undergoing fatigue test ...structure. Bridge test site with prepared embankments corresponding to the span and bank condition requirements of the bridge under test Conduct real...Center (AEC). (5) Sample size and number of crossings required. The number of required simulated crossings to conduct fatigue testing per the

  19. Cyano-bridged structures based on [MnIIN3O2-macrocycle)]2+: a synthetic, structural, and magnetic study.

    Science.gov (United States)

    Bonadio, Federica; Senna, Maria-Cristina; Ensling, Jürgen; Sieber, Andreas; Neels, Antonia; Stoeckli-Evans, Helen; Decurtins, Silvio

    2005-02-21

    Reactions between the complex [MnII(L)]2+, where L is a N3O2 macrocyclic ligand, and different cyanometalate precursors such as [M(CN)n]m- (M(III) = Cr, Fe; M(II) = Fe, Ni, Pd, Pt) lead to cyano-bridged molecular assemblies exhibiting a variety of structural topologies. The reaction between [MnII(L)]2+ and [FeII(CN)6]4- forms a trinuclear complex with formula [(MnII(L)(H2O))2(FeII(micro-CN)2(CN)4)] x 2MeOH x 10H2O (1) which crystallizes in the triclinic space group P1. The reaction between [MnII(L)]2+ and [M(II)(CN)4]2-, where M(II) = Ni (2), Pd (3), Pt (4), gives rise to three isostructural linear chain compounds with stoichiometry [(MnII(L))(M(II)(micro-CN)2(CN)2)]n and which crystallize in the monoclinic space group C2/c. The self-assembly between [MnII(L)]2+ with [M(III)(CN)6]3-, where M(III) = Cr (5), Fe (6, 7, 8), forms three types of compounds. Compounds 5 and 6 are isostructural (monoclinic, space group P2(1)/n), and the structures comprise anionic linear chains [(MnII(L))(M(III)(micro-CN)2(CN)4)]n(n-) with cationic trinuclear complexes [(MnII(L)(H2O))2(M(III)(micro-CN)2(CN)4)]+ as counterions. Using an excess of K3[FeIII(CN)6], an analogous compound to 6 but with K+ as counterion is obtained (7), which crystallizes in the triclinic space group P1. Compound 8 consists of 2-D layers with formula [(MnII(L))3(FeIII(micro-CN)4(CN)2)(FeIII(micro-CN)2(CN)4)]n x 2nMeOH; it crystallizes in the monoclinic space group P2(1)/n. The magnetic properties were investigated for all samples. In particular, compound 5, which shows antiferromagnetic exchange interactions between Mn(II) and Cr(III) ions through cyanide bridging ligands, has been studied in detail; the magnetic exchange parameter amounts to J = -7.5(7) cm(-1). Compound 8 shows a magnetically ordered phase below 6.4 K which is confirmed by Mössbauer spectroscopy; two hyperfine split spectra were observed below Tc from which IJI values of 2.1 and 1.6 cm(-1) could be deduced.

  20. Bridging structure with function: structural, regulatory, and developmental role of laminins.

    Science.gov (United States)

    Tzu, Julia; Marinkovich, M Peter

    2008-01-01

    The basement membrane is a highly intricate and organized portion of the extracellular matrix that interfaces with a variety of cell types including epithelial, endothelial, muscle, nerve, and fat cells. The laminin family of glycoproteins is a major constituent of the basement membrane. The 16 known laminin isoforms are formed from combinations of alpha, beta, and gamma chains, with each chain containing specific domains capable of interacting with cellular receptors such as integrins and other extracellular ligands. In addition to its role in the assembly and architectural integrity of the basement membrane, laminins interact with cells to influence proliferation, differentiation, adhesion, and migration, processes activated in normal and pathologic states. In vitro these functions are regulated by the post-translational modifications of the individual laminin chains. In vivo laminin knockout mouse studies have been particularly instructive in defining the function of specific laminins in mammalian development and have also highlighted its role as a key component of the basement membrane. In this review, we will define how laminin structure complements function and explore its role in both normal and pathologic processes.

  1. Railroad Bridges

    Data.gov (United States)

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

  2. Experimental evaluation of the buckling phenomena in the new joint design for upper deck structure of a bridge

    Directory of Open Access Journals (Sweden)

    Solazzi L.

    2010-06-01

    Full Text Available This paper is concerned with the experimental mechanical analysis of a new design of a joint for a main components of a upper deck of a road bridge. These components are subject to the compression state stress induced by the weight and the load acting on the road. Each upper deck of a bridge (positioned on each side of the bridge is composed by four tubular structures that must be joint each together. The joint must to take in to account many aspects, for example that the length of each component is not the same (because, obviously, there is a mechanical tolerance. This phenomena induce different compression stress on each component and so is very important non only the critical buckling load but also the post buckling behaviour of the structure. It is very important that if a single tubular structure reaches the critical load of instability, it still has load capacity . This is to avoid that, in the case where a column reaches the instability, the entire load acting on a column increase the load on the remaining three. For this purpose many different geometrical solutions have been designed (elaborated by fem analyses and successively tested experimentally. This work reports the main experimental results on the best joint solution and how this increase the load capacity and the displacement respect to the solution without this flange.

  3. Nanoscopic structural rearrangements of the Cu-filament in conductive-bridge memories

    Science.gov (United States)

    Celano, U.; Giammaria, G.; Goux, L.; Belmonte, A.; Jurczak, M.; Vandervorst, W.

    2016-07-01

    The electrochemical reactions triggering resistive switching in conductive-bridge resistive random access memory (CBRAM) are spatially confined in few tens of nm3. The formation and dissolution of nanoscopic Cu-filaments rely on the displacement of ions in such confined volume, and it is driven by the electric field induced ion migration and nanoscaled redox reactions. The stochastic nature of these fundamental processes leads to a large variability of the device performance. In this work, a combination of two- and three-dimensional scanning probe microscopy (SPM) techniques are used to study the conductive filament (CF) formation, rupture and its nanoscopic structural rearrangements. The high spatial confinement of our approach enables to locally induce RS in a confined area and image it in 3D. A conical shape of the CF is consistently observed, indicating that the ion migration is the rate limiting step in the filament formation when using high quality dielectrics as switching layers. The sub-10 nm electrical contact size of the AFM tip is used to study the filament's dissolution and detect the hopping conduction of Cu during the CF rupture. We consistently observe a tunnel gap formation associated with the tip-induced filament reset. Finally, aiming to match the fundamental understanding with the integrated device operations, we apply scalpel SPM to failed memory cells and directly observe the appearance of filament multiplicity as a major source of failures and variability in CBRAM.The electrochemical reactions triggering resistive switching in conductive-bridge resistive random access memory (CBRAM) are spatially confined in few tens of nm3. The formation and dissolution of nanoscopic Cu-filaments rely on the displacement of ions in such confined volume, and it is driven by the electric field induced ion migration and nanoscaled redox reactions. The stochastic nature of these fundamental processes leads to a large variability of the device performance. In this

  4. Mathematical bridges

    CERN Document Server

    Andreescu, Titu; Tetiva, Marian

    2017-01-01

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

  5. Theoretical investigation on structure and electronic properties of Si-bridged π-conjugated systems

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Eisuke; Matsui, Yasunori; Ikeda, Hiroshi [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan); The Research Institute for Molecular Electronic Devices (RIMED), Osaka Prefecture University, 1-" 1Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan); Ogaki, Takuya; Aoki, Toru; Oda, Yukiko [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan)

    2015-12-31

    Density functional theory calculations were performed on silylene-bridged cyclic tri- and tetrathienylenes, 1b and 2b, respectively. The results show that in comparison to their respective unbridged counterparts 1a and 2a, 1b and 2b have lower LUMO energies but similar reorganization energies for single electron transfer between 1b,2b and their respective radical anions 1b{sup •–},2b{sup •–}. The observations suggest that silylene bridging of π-conjugated systems can serve as a novel strategy for designing materials of n-type organic semiconductor.

  6. Structural behavior of reinforced concrete slab rigid frame bridge with h-shaped steels

    OpenAIRE

    Fukada, Saiji; Kajikawa, Y.; Tokuno, M.

    2008-01-01

    The authors proposed a reinforced concrete slab bridge with H-shaped steels which has high load-carrying capacity in order to reduce the construction cost. Our past study clarified that H-shape steels without stud dowel and concrete could compose hybrid section and static load was equally distributed each H-shaped steel in elasticity stage. Considering the described above it is possible to design this type of bridge as composite. Moreover it clarified that the cyclically loaded this type brid...

  7. Peer review of the National Transportation Safety Board structural analysis of the I-35W bridge collapse.

    Energy Technology Data Exchange (ETDEWEB)

    Gwinn, Kenneth West; Redmond, James Michael; Wellman, Gerald William

    2008-10-01

    The Engineering Sciences Center at Sandia National Laboratories provided an independent peer review of the structural analysis supporting the National Transportation Safety Board investigation of the August 1, 2007 collapse of the I-35W Bridge in Minneapolis. The purpose of the review was to provide an impartial critique of the analysis approach, assumptions, solution techniques, and conclusions. Subsequent to reviewing numerous supporting documents, a SNL team of staff and management visited NTSB to participate in analysis briefings, discussions with investigators, and examination of critical elements of the bridge wreckage. This report summarizes the opinion of the review team that the NTSB analysis effort was appropriate and provides compelling supporting evidence for the NTSB probable cause conclusion.

  8. A trans-1,2 End-On Disulfide-Bridged Iron-Tetracarbene Dimer and Its Electronic Structure.

    Science.gov (United States)

    Meyer, Steffen; Krahe, Oliver; Kupper, Claudia; Klawitter, Iris; Demeshko, Serhiy; Bill, Eckhard; Neese, Frank; Meyer, Franc

    2015-10-19

    A disulfide-bridged diiron complex with [Fe-S-S-Fe] core, which represents an isomer of the common biological [2Fe-2S] ferredoxin-type clusters, was synthesized using strongly σ-donating macrocyclic tetracarbene capping ligands. Though the complex is quite labile in solution, single crystals were obtained, and the structure was elucidated by X-ray diffraction. The electron-rich iron-sulfur core is found to show rather unusual magnetic and electronic properties. Experimental data and density functional theory studies indicate extremely strong antiferromagnetic coupling (-J > 800 cm(-1)) between two low-spin iron(III) ions via the S2(2-) bridge, and the intense near-IR absorption characteristic for the [Fe-S-S-Fe] core was assigned to a S → Fe ligand-to-metal charge transfer transition.

  9. A Crack Identification Method for Bridge Type Structures under Vehicular Load Using Wavelet Transform and Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Hakan Gökdağ

    2013-01-01

    Full Text Available In this work a crack identification method is proposed for bridge type structures carrying moving vehicle. The bridge is modeled as an Euler-Bernoulli beam, and open cracks exist on several points of the beam. Half-car model is adopted for the vehicle. Coupled equations of the beam-vehicle system are solved using Newmark-Beta method, and the dynamic responses of the beam are obtained. Using these and the reference displacements, an objective function is derived. Crack locations and depths are determined by solving the optimization problem. To this end, a robust evolutionary algorithm, that is, the particle swarm optimization (PSO, is employed. To enhance the performance of the method, the measured displacements are denoised using multiresolution property of the discrete wavelet transform (DWT. It is observed that by the proposed method it is possible to determine small cracks with depth ratio 0.1 in spite of 5% noise interference.

  10. Structural assessment of a RC Bridge over Sororó river along the Carajás railway

    Directory of Open Access Journals (Sweden)

    J. C. L. Matos

    Full Text Available The Carajás railway is operated by Vale SA and is used to transport the Brazilian production of iron ore mine located in the state of Pará until Itaqui harbor in Maranhão state. With 892 km in length, the railway will be doubled due to the prospect of increased production, which requires verification of the structures of bridges to ensure safety under loading up to 23% larger. The railway bridge in reinforced concrete has five hyperstatic spans with 25 m long and was built over Sororó river in the southeast of Pará. To better evaluate its structural performance under current loadings, several structural elements were monitored with strain gages and the concrete was characterized by non-destructive and destructive testing on the structure. This information was used in a computer model to estimate the future structural behavior. The methodology was satisfactory as the estimated structural performance for future loadings, meeting the recommendations of the Brazilian technical standards.

  11. Two new hexacoordinated coordination polymers of cadmium(II) containing bridging units only: Syntheses, structures and molecular properties

    Indian Academy of Sciences (India)

    DIPU SUTRADHAR; HABIBAR CHOWDHURY; SUSHOVAN KONER; SUBHASIS ROY; BARINDRA KUMAR GHOSH

    2016-09-01

    The syntheses, characterizations and structures of a neutral 2D coordination polymer [Cd(bnzd)(NCS)₂]n (1) and a polycationic 3D coordination polymer isolated as perchlorate salt [Cd(bnzd)₃]n(ClO₄)₂n (2) (bnzd = benzidine) are described. X-ray structural analyses reveal that each hexacoordinated cadmium(II) center in 1 adopts a distorted octahedral geometry with a CdN₄S₂ chromophore bound by two N atoms of two different bnzd units and two N and two S atoms of symmetric doubly bridged end-toend NCS− units extended in a 2D sheet. Six N atoms of six different bridged bnzd units are bonded to each cadmium(II) in 2 in a non-ended fashion affording a 3D network structure. In the crystalline state, each 2D sheet structure in 1 is further stabilized by π· · ·π interaction which in turn affords a 3D network structure through multiple intermolecular N-H· · · S hydrogen bonds. On the other hand, the 3D network structure in 2 is stabilized by weak intermolecular N-H· · ·O hydrogen bonds and C-H· · ·π interactions. Bnzd, 1 and 2 display intraligand 1(π-π*) fluorescence in DMF solution at room temperature.

  12. Fabrication of air-bridged Kerr nonlinear polymer photonic crystal slab structures in near-infrared region

    Institute of Scientific and Technical Information of China (English)

    Ziming Meng; Xiaolan Zhong; Chen Wang; Zhiyuan Li

    2012-01-01

    Fabrication details of air-bridged Kerr nonlinear polymer photonic crystal slab structures are presented.Both the two-dimensional photonic crystal slab and the one-dimensional nanobeam structures are fabricated using direct focused ion beam etching and subsequent wet chemical etching.The scanning electron microscopy images show the uniformity and homogeneity of the cylindrical air holes.The optical measurement in the near-infrared region is implemented using the tapered fiber coupling method,and the results agree with the numerical calculations by using the three-dimensional finite-difference time-domain method.

  13. Analysis of the dominant vibration frequencies of rail bridges for structure-borne noise using a power flow method

    Science.gov (United States)

    Li, Q.; Wu, D. J.

    2013-09-01

    The use of concrete bridges in urban rail transit systems has raised many concerns regarding low-frequency (20-200 Hz) structure-borne noise due to the vibration of bridges when subjected to moving trains. Understanding the mechanism that determines the dominant frequencies of bridge vibrations is essential for both vibration and noise reduction. This paper presents a general procedure based on the force method to obtain the power flows within a coupled vehicle-track-bridge system, the point mobility of the system and the dynamic interaction forces connecting various components. The general coupling system consists of multi-rigid-bodies for the vehicles, infinite Euler beams representing the rails, two-dimensional or three-dimensional elements of the concrete bridges, and spring-dashpot pairs to model the wheel-rail contacts, the vehicle suspensions, the rail pads and the bridge bearings. The dynamic interaction of the coupled system is solved in the frequency domain by assuming the combined wheel-rail roughness moves forward relative to the stationary vehicles. The proposed procedure is first applied to a rail on discrete supports and then to a real urban rail transit U-shaped concrete bridge. The computed results show that the wheel-rail contact forces, the power flows to the rail/bridge subsystem and the accelerations of the bridge are primarily dominated by the contents around the natural frequency of a single wheel adhered to the elastically supported rail. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same rigid body, then δmnab(ω) can be expressed as δmnab(ω)=-{(}/{Mlω}, where Ml is the mass of the lth rigid body. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same infinite rail, δmnab(ω) can be expressed as [8] δmnab(ω)=-j{((e-je)}/{4EIk}, where xm and xn are the x-coordinates of the mth and nth spring

  14. Structure and dynamics of a salt-bridge model system in water and DMSO.

    Science.gov (United States)

    Lotze, S; Bakker, H J

    2015-06-01

    We study the interaction between the ions methylguanidinium and trifluoroacetate dissolved in D2O and dimethylsulfoxide with linear infrared spectroscopy and femtosecond two-dimensional infrared spectroscopy. These ions constitute model systems for the side chains of arginine and glutamic and aspartic acid that are known to form salt bridges in proteins. We find that the salt-bridge formation of methylguanidinium and trifluoroacetate leads to a significant acceleration of the vibrational relaxation dynamics of the antisymmetric COO stretching vibration of the carboxyl moiety of trifluoroacetate. Salt-bridge formation has little effect on the rate of the spectral fluctuations of the CN stretching vibrations of methylguanidinium. The anisotropy of the cross peaks between the antisymmetric COO stretching vibration of trifluoroacetate and the CN stretching vibrations of methylguanidinium reveals that the salt-bridge is preferentially formed in a bidentate end-on configuration in which the two C=O groups of the carboxylate moiety form strong hydrogen bonds with the two -NH2 groups of methylguanidinium.

  15. The Namibia bridge management system: a tool for preservation of structures on the road network

    CSIR Research Space (South Africa)

    Roux, MP

    2010-10-01

    Full Text Available for the management of 6 200 km of paved roads and 35 900 km of unpaved roads, which includes 1 430 bridges and major culverts (>3m span length) and 1 290 lesser culverts (<3 m span). In 2001, the NRA embarked on a project to upgrade their existing BMS, which...

  16. Towards managed structuration : Exploring bridging mechanisms for IS enabled change in multi-site implementation projects

    NARCIS (Netherlands)

    Hage, Eveline; van Offenbeek, Marjolein; Boonstra, Albert

    2015-01-01

    This paper aims to enhance our understanding of the bridging mechanisms underlying information system (IS) enabled change in multi-site implementation projects, and explore opportunities for intentionally shaping such change. To achieve this, we develop and empirically demonstrate the added value of

  17. Structure-driven homology pairing of chromatin fibers: the role of electrostatics and protein-induced bridging.

    Science.gov (United States)

    Cherstvy, A G; Teif, V B

    2013-06-01

    Chromatin domains formed in vivo are characterized by different types of 3D organization of interconnected nucleosomes and architectural proteins. Here, we quantitatively test a hypothesis that the similarities in the structure of chromatin fibers (which we call "structural homology") can affect their mutual electrostatic and protein-mediated bridging interactions. For example, highly repetitive DNA sequences in heterochromatic regions can position nucleosomes so that preferred inter-nucleosomal distances are preserved on the surfaces of neighboring fibers. On the contrary, the segments of chromatin fiber formed on unrelated DNA sequences have different geometrical parameters and lack structural complementarity pivotal for stable association and cohesion. Furthermore, specific functional elements such as insulator regions, transcription start and termination sites, and replication origins are characterized by strong nucleosome ordering that might induce structure-driven iterations of chromatin fibers. We propose that shape-specific protein-bridging interactions facilitate long-range pairing of chromatin fragments, while for closely-juxtaposed fibers electrostatic forces can in addition yield fine-tuned structure-specific recognition and pairing. These pairing effects can account for some features observed for mitotic and inter-phase chromatins.

  18. Synthesis, crystal structure and magnetic characterization of a cyanide-bridged Mo-Ni nanosized molecular wheel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Daopeng; Zhang, Hongyan; Wang, Ping [Shandong Univ. of Technology, College of Chemical Engineering, Zibo (China); Kong, Lingqian [Liaocheng Univ. (China). Dongchang College

    2015-11-01

    By using K{sub 4}[Mo(CN){sub 8}] and [Ni(L)(H{sub 2}O){sub 2}][ClO{sub 4}]{sub 2} as reagents (L = 2,12-dimethyl-3,7,11,17-tetraazabicyclo [11.3.1]heptadeca-1(17),13,15-triene), a new cyanide-bridged Mo-Ni complex containing the building blocks [Ni(H{sub 2}O)(L)]{sup 2+} and [Ni(L)]{sup 2+} bridged by [Mo(CN){sub 8}]{sup 4-} units has been obtained. The complex with the formula {[Ni(H_2O)(L)][Ni(L)][Mo(CN)_8]}{sub 6} . 36H{sub 2}O . 2CH{sub 3}OH (1) was characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The structure determination reveals an octadecanuclear cluster in the form of a 36-membered macrocycle, in which the largest intramolecular W..W and Ni..Ni distances are 16.5 and 14.4 Aa, respectively, indicating that complex 1 is a nanosized molecular wheel. Investigation of its magnetic properties has shown weak antiferromagnetic coupling between the adjacent Ni(II) ions bridged by the diamagnetic [Mo(CN){sub 8}]{sup 4-} ions.

  19. The Role of the Conjugate Bridge in Electronic Structures and Related Properties of Tetrahydroquinoline for Dye Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    You-Zhi Wu

    2013-03-01

    Full Text Available To understand the role of the conjugate bridge in modifying the properties of organic dye sensitizers in solar cells, the computations of the geometries and electronic structures for 10 kinds of tetrahydroquinoline dyes were performed using density functional theory (DFT, and the electronic absorption and fluorescence properties were investigated via time dependent DFT. The population analysis, molecular orbital energies, radiative lifetimes, exciton binding energies (EBE, and light harvesting efficiencies (LHE, as well as the free energy changes of electron injection ( and dye regeneration ( were also addressed. The correlation of charge populations and experimental open-circuit voltage (Voc indicates that more charges populated in acceptor groups correspond to larger Voc. The elongating of conjugate bridge by thiophene units generates the larger oscillator strength, higher LHE, larger absolute value of , and longer relative radiative lifetime, but it induces the decreasing of EBE and . So the extending of conjugate bridge with thiopene units in organic dye is an effective way to increase the harvest of solar light, and it is also favorable for electron injection due to their larger . While the inversely correlated relationship between EBE and LHE implies that the dyes with lower EBE produce more efficient light harvesting.

  20. Large vortex-like structure of dipole field in computer models of liquid water and dipole-bridge between biomolecules.

    Science.gov (United States)

    Higo, J; Sasai, M; Shirai, H; Nakamura, H; Kugimiya, T

    2001-05-22

    We propose a framework to describe the cooperative orientational motions of water molecules in liquid water and around solute molecules in water solutions. From molecular dynamics (MD) simulation a new quantity "site-dipole field" is defined as the averaged orientation of water molecules that pass through each spatial position. In the site-dipole field of bulk water we found large vortex-like structures of more than 10 A in size. Such coherent patterns persist more than 300 ps although the orientational memory of individual molecules is quickly lost. A 1-ns MD simulation of systems consisting of two amino acids shows that the fluctuations of site-dipole field of solvent are pinned around the amino acids, resulting in a stable dipole-bridge between side-chains of amino acids. The dipole-bridge is significantly formed even for the side-chain separation of 14 A, which corresponds to five layers of water. The way that dipole-bridge forms sensitively depends on the side-chain orientations and thereby explains the specificity in the solvent-mediated interactions between biomolecules.

  1. Fixation of CO2 in air: Synthesis and crystal structure of a 3-CO3-bridged tricopper(II) compound

    Indian Academy of Sciences (India)

    Jhumpa Mukherjee; V Balamurugan; Maninder Singh Hundal; Rabindranath Mukherjee

    2005-03-01

    A novel trinuclear copper(II) compound [{(L3)Cu(OClO3)}3(3-OCO2)][ClO4] has been synthesised using an N-tridentate symmetrical pyridylalkylamine ligand, N-methyl-N,N-bis(2-pyridylmethyl)amine (L3). The structure of the complex has been determined by X-ray crystallography; it is found to crystallise in the hexagonal space group 63/ with = 13.936(2), = 13.936(2), = 14.895(3) Å, = = 90°, = 120°. The complex possesses a $\\bar{6}$ - symmetry axis passing through the carbon atom of the triply bridging carbonate ion, with the three symmetry related copper ions connected to one another through the oxygen atoms from the bridging carbonato group, giving an equilateral triangular array of copper centres. Each copper ion has distorted square pyramidal environment with the basal plane formed by three nitrogen atoms of the ligand L3 and the oxygen atom of the bridging carbonato group. The apical position at each copper is provided by the weak oxygen coordination from the perchlorate ion.

  2. Bridge and steel structures. Wind resistant design and vibration control; Kyoryo kokozobutsu. Taifu seishin gijutsu no kojo wo mezashite

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, M.; Takeuchi, T.; Saito, Y.; Kazama, K. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1998-08-20

    This paper describes the wind resistant design and vibration control of bridges. For the long span bridges, vibration by wind is worried due to their flexible structures. Wind tunnel tests are conducted, and the shape of bridges is modified on the basis of the test results. On the other hand, tuned mass dampers (TMDs) are often used during the construction with footing for a short period. For the passive TMD which is a general pendulum type, the number of vibration frequency can be variable by changing the position of spring and damper. The restitutive force can be obtained for the vertical Vibration using lever-type weight damper and spring. For the Active TMD, the weight of lever-type damper is driven by the servo-motor using rack pinion. An optimum regulator is used for the control. Sufficient damping performance was obtained by applying this to the main tower, which depended on the gain and vibration amplitude. An aerodynamic damper is used for the vibration of cables by the wind. Especially, the rain vibration is a problem, which is due to the interaction of rain flow and wind. To solve this problem, a U-engrave cable has been developed for preventing the formation of rainwater flow channels on the cable surface. 9 refs., 14 figs., 5 tabs.

  3. Synthesis, Characterization and Crystal Structure Determination of a Thiocyanato Bridged One-dimensional Polymeric Complex of Cadmium(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    BAI Yan; PAN Xiao-Jing; DANG Dong-Bin; SHANG Wei-Li; WANG Jing-Ping

    2008-01-01

    A new one-dimensional polymeric complex [Cd(SCN)2(H2O)]L (L = N,N'-bis(furan-2-ylmethylene)hydrazine) has been synthesized and characterized by IR, UV spectra, TG-DTA technique and single-crystal X-ray diffraction analysis. It crystallizes in triclinic, pace group P1 with a = 5.9268(8), b = 10.8678(15), c = 13.3671(19) A, α = 109.295(2), β = 95.092(2), γ =97.8580(10)°, V - 796.70(19) A3, Z = 2, C12H10CdN4O3S2, Mr = 434.76, μ = 1.648 mm-1, Dc = 1.812 g/cm3, F(000) = 428, R = 0.0308 and wR = 0.0769. The crystal structure reveals that the structure of [Cd(SCN)E(H2O)]n features di-μ-1,3-thiocyante bridges and 1D chains. The octahedrally coordinated Cd atom is surrounded by one oxygen atom from water molecule, three S atoms and two N atoms from five di-μ-1,3 thiocyanato bridges. The Cd atoms are connected by two di-μ-1,3 thiocyanato bridges with the Cd(1)…Cd(1A) separation of 4.239(1) (A) and Cd(1)…Cd(1B) of 5.852(1)(A). In addition, the one-dimensional straight chain structure is further connected by multiform intermolicular N-H…O hydrogen bonds and π…π interactions to form a three-dimensional supramolecular structure.

  4. Crystal structures of mono- and bi-specific diabodies and reduction of their structural flexibility by introduction of disulfide bridges at the Fv interface

    Science.gov (United States)

    Kim, Jin Hong; Song, Dong Hyun; Youn, Suk-Jun; Kim, Ji Won; Cho, Geunyoung; Kim, Sun Chang; Lee, Hayyoung; Jin, Mi Sun; Lee, Jie-Oh

    2016-01-01

    Building a sophisticated protein nano-assembly requires a method for linking protein components in a predictable and stable structure. Diabodies are engineered antibody fragments that are composed of two Fv domains connected by short peptide linkers. They are attractive candidates for mediators in assembling protein nano-structures because they can simultaneously bind to two different proteins and are rigid enough to be crystallized. However, comparison of previous crystal structures demonstrates that there is substantial structural diversity in the Fv interface region of diabodies and, therefore, reliable prediction of its structure is not trivial. Here, we present the crystal structures of ten mono- and bi-specific diabodies. We found that changing an arginine residue in the Fv interface to threonine greatly reduced the structural diversity of diabodies. We also found that one of the bispecific diabodies underwent an unexpected process of chain swapping yielding a non-functional monospecific diabody. In order to further reduce structural flexibility and prevent chain shuffling, we introduced disulfide bridges in the Fv interface regions. The disulfide-bridged diabodies have rigid and predictable structures and may have applications in crystallizing proteins, analyzing cryo-electron microscopic images and building protein nano-assemblies. PMID:27682821

  5. Synthesis and crystal structures of three isophthalato-bridged macrocyclic nickel(II) complexes

    Indian Academy of Sciences (India)

    Guang-Chuan Ou; Zhi-Zhang Li; Lin Yuan; Xian-You Yuan

    2015-01-01

    Three dinuclear isophthalato-bridged nickel(II) complexes formulated as [Ni(rac-L)]2(-IPA)(ClO4)2 (1), [Ni(-L)]2(-IPA)(ClO4)2 (2) and [Ni(SS-L)]2(-IPA)(ClO4)2 (3) (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyc-lotetradecane, IPA = isophthalic acid) have been isolated and characterized. Single crystal X-ray diffraction analyses revealed that the Ni(II) atoms have six-coordinated distorted octahedral environments, and the isophthalato ligand bridges two Ni(II) centres in a bis bidentate fashion to form dimers in all three complexes. The monomers of {[Ni(-L)]2(-IPA)}2+ are connected through intermolecular hydrogen bonds to generate one-dimensional left-handed helical chains in complex 3. The homochiral natures of complexes 2 and 3 have been confirmed by CD spectroscopy.

  6. Finite element model updating of existing steel bridge based on structural health monitoring

    Institute of Scientific and Technical Information of China (English)

    HE Xu-hui; YU zhi-wu; CHEN Zheng-qing

    2008-01-01

    Based on the physical meaning of sensitivity, a new finite element (FE) model updating method was proposed. In this method, a three-dimensional FE model of the Nanjing Yangtze River Bridge (NYRB) with ANSYS program was established and updated by modifying some design parameters. To further validate the updated FE model, the analytical stress-time histories responses of main members induced by a moving train were compared with the measured ones. The results show that the relative error of maximum stress is 2.49% and the minimum relative coefficient of analytical stress-time histories responses is 0.793. The updated model has a good agreement between the calculated data and the tested data, and provides a current baseline FE model for long-term health monitoring and condition assessment of the NYRB. At the same time, the model is validated by stress-time histories responses to be feasible and practical for railway steel bridge model updating.

  7. Full implementations of structural health monitoring systems for long-span bridges and large-span domes

    Science.gov (United States)

    Li, Hui; Ou, Jinping

    2006-03-01

    In this paper, full implementations of structural health monitoring systems for long-span bridges and large-span domes are introduced. The frameworks of the health monitoring systems are introduced. The types and locations of sensors are also presented. The data acquisition system, including scheme of data acquisition system, strategies of collecting data, instrument and software used in the data acquisition system, is described. The data transmitting system, data management system and warning system are also designed. Based on the data collected by the structural health monitoring systems, response and dynamic properties of the structures, and the loads are statistically analyzed. Finite element (FE) model is updated based on the measured data by structural health monitoring.

  8. Demonstration of Corrosion-Resistant Hybrid Composite Bridge Beams for Structural Applications

    Science.gov (United States)

    2016-09-01

    provided by the guard rails was removed. Observed friction at the beam bearings, which resulted in beam rotational end-restraint, was reduced...as com- pared with conventional beams, offer advantages in terms of lower ship- ping weight and reduced equipment requirements for hoisting beams into...indicated some girder movement at the bearing and bridge rail locations. This behavior was most likely a function of friction between the elastomeric

  9. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...

  10. Modelling of double air-bridged structured inductor implemented by a GaAs integrated passive device manufacturing process

    Science.gov (United States)

    Li, Yang; Yao, Zhao; Zhang, Chun-Wei; Fu, Xiao-Qian; Li, Zhi-Ming; Li, Nian-Qiang; Wang, Cong

    2017-05-01

    In order to provide excellent performance and show the development of a complicated structure in a module and system, this paper presents a double air-bridge-structured symmetrical differential inductor based on integrated passive device technology. Corresponding to the proposed complicated structure, a new manufacturing process fabricated on a high-resistivity GaAs substrate is described in detail. Frequency-independent physical models are presented with lump elements and the results of skin effect-based measurements. Finally, some key features of the inductor are compared; good agreement between the measurements and modeled circuit fully verifies the validity of the proposed modeling approach. Meanwhile, we also present a comparison of different coil turns for inductor performance. The proposed work can provide a good solution for the design, fabrication, modeling, and practical application of radio-frequency modules and systems.

  11. Comparison of wing-span averaging effects on lift, rolling moment, and bending moment for two span load distributions and for two turbulence representations

    Science.gov (United States)

    Lichtenstein, J. H.

    1978-01-01

    An analytical method of computing the averaging effect of wing-span size on the loading of a wing induced by random turbulence was adapted for use on a digital electronic computer. The turbulence input was assumed to have a Dryden power spectral density. The computations were made for lift, rolling moment, and bending moment for two span load distributions, rectangular and elliptic. Data are presented to show the wing-span averaging effect for wing-span ratios encompassing current airplane sizes. The rectangular wing-span loading showed a slightly greater averaging effect than did the elliptic loading. In the frequency range most bothersome to airplane passengers, the wing-span averaging effect can reduce the normal lift load, and thus the acceleration, by about 7 percent for a typical medium-sized transport. Some calculations were made to evaluate the effect of using a Von Karman turbulence representation. These results showed that using the Von Karman representation generally resulted in a span averaging effect about 3 percent larger.

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

    Science.gov (United States)

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

    2015-08-01

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

  13. Atomic fingers, bridges and slingshots: formation of exotic surface structures during ion irradiation of heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Nordlund, K. E-mail: kai.nordlund@helsinki.fi; Tarus, J.; Keinonen, J.; Donnelly, S.E.; Birtcher, R.C

    2003-05-01

    Recent experiments on ion irradiation of heavy metals such as gold and silver have shown that very unusual surface configurations can be produced by the irradiation. Typically, the surface damage has the shape of a crater, similar to those produced by meteorite impacts. The crater shapes are, however, often highly asymmetric and can show extended adatom ridges extending far from the crater well. Using molecular dynamics simulations we show how such exotic atom arrangements are produced. We describe atomic bridges over a crater and illustrate a slingshot-like effect which can propel atom clusters far from an impact position to produce isolated adatom islands.

  14. Bridge deck surface temperature monitoring by infrared thermography and inner structure identification using PPT and PCT analysis methods

    Science.gov (United States)

    Dumoulin, Jean

    2013-04-01

    One of the objectives of ISTIMES project was to evaluate the potentialities offered by the integration of different electromagnetic techniques able to perform non-invasive diagnostics for surveillance and monitoring of transport infrastructures. Among the EM methods investigated, we focused our research and development efforts on uncooled infrared camera techniques due to their promising potential level of dissemination linked to their relative low cost on the market. On the other hand, works were also carried out to identify well adapted implementation protocols and key limits of Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) processing methods to analyse thermal image sequence and retrieve information about the inner structure. So the first part of this research works addresses infrared thermography measurement when it is used in quantitative mode (not in laboratory conditions) and not in qualitative mode (vision applied to survey). In such context, it requires to process in real time thermal radiative corrections on raw data acquired to take into account influences of natural environment evolution with time, thanks to additional measurements. But, camera sensor has to be enough smart to apply in real time calibration law and radiometric corrections in a varying atmosphere. So, a complete measurement system was studied and developed [1] with low cost infrared cameras available on the market. In the system developed, infrared camera is coupled with other sensors to feed simplified radiative models running, in real time, on GPU available on small PC. The whole measurement system was implemented on the "Musmeci" bridge located in Potenza (Italy). No traffic interruption was required during the mounting of our measurement system. The infrared camera was fixed on top of a mast at 6 m elevation from the surface of the bridge deck. A small weather station was added on the same mast at 1 m under the camera. A GPS antenna was also fixed at the

  15. Synthesis and structural characterization of a calcium coordination polymer based on a 3-bridging tetradentate binding mode of glycine

    Indian Academy of Sciences (India)

    Subramanian Natarajan; Bikshandarkoil R Srinivasan; J Kalyana Sundar; K Ravikumar; R V Krishnakumar; J Suresh

    2012-07-01

    A new coordination polymer namely [[Ca6(H-gly)12(H2O)18]Cl12·6H2O] (1) (H-gly = glycine) has been isolated from the calcium chloride-glycine-water system and structurally characterized. Each Ca(II) in 1 is eight-coordinated and is bonded to eight oxygen atoms three of which are from terminal water molecules and five oxygen atoms from four symmetry related zwitterionic glycine ligands. The H-gly ligands exhibit two different binding modes viz. a monodentate carboxylate ligation and a 3-tetradentate bridging carboxylate binding mode, which results in the formation of a one-dimensional coordination polymer. In the infinite chain the Ca(II) atoms are organized in a zigzag fashion. A comparative study reveals a rich and diverse structural chemistry of calcium halide-glycine compounds.

  16. Fluoride Bridges as Structure-Directing Motifs in 3d-4f Cluster Chemistry

    DEFF Research Database (Denmark)

    Birk, Torben; Pedersen, Kasper; Thuesen, Christian Aa.

    2012-01-01

    ,2′-bipyridine (“bpy”)) with Ln(NO3)3·xH2O produces isostructural series of molecular {Ln2Cr2} squares (1–9) with linear fluoride bridges. In a parallel fashion, fac-[CrIIIF3L], where L = N,N′,N″-trimethyl-1,4,7-triazacyclononane (“Me3tacn”), reacts with Nd(NO3)3·6H2O to form a fluoride-centered penta...... by a partial solvolysis of the Cr(III) precursor but without formation of insoluble LnF3. The magnetic properties of the gadolinium containing clusters allow quantification of fluoride-mediated, antiferromagnetic Gd–Cr exchange interactions of magnitude between 0.14 cm–1 and 0.71 cm–1 (Ĥ = J12Ŝ1·Ŝ2...

  17. Radical aryl migration enables diversity-oriented synthesis of structurally diverse medium/macro- or bridged-rings

    Science.gov (United States)

    Li, Lei; Li, Zhong-Liang; Wang, Fu-Li; Guo, Zhen; Cheng, Yong-Feng; Wang, Na; Dong, Xiao-Wu; Fang, Chao; Liu, Jingjiang; Hou, Chunhui; Tan, Bin; Liu, Xin-Yuan

    2016-12-01

    Medium-sized and medium-bridged rings are attractive structural motifs in natural products and therapeutic agents. Due to the unfavourable entropic and/or enthalpic factors with these ring systems, their efficient construction remains a formidable challenge. To address this problem, we herein disclose a radical-based approach for diversity-oriented synthesis of various benzannulated carbon- and heteroatom-containing 8-11(14)-membered ketone libraries. This strategy involves 1,4- or 1,5-aryl migration triggered by radical azidation, trifluoromethylation, phosphonylation, sulfonylation, or perfluoroalkylation of unactivated alkenes followed by intramolecular ring expansion. Demonstration of this method as a highly flexible tool for the construction of 37 synthetically challenging medium-sized and macrocyclic ring scaffolds including bridged rings with diverse functionalities and skeletons is highlighted. Some of these products showed potent inhibitory activity against the cancer cell or derivative of human embryonic kidney line in preliminary biological studies. The mechanism of this novel strategy is investigated by control experiments and DFT calculations.

  18. Fabrication and construction of major steel bridge structure arch rib of Wuxi Xingtang Bridge%无锡兴塘大桥主桥钢结构拱肋制作与施工

    Institute of Scientific and Technical Information of China (English)

    韩荣刚

    2012-01-01

    Combining with the specialty of the fabrication,welding,and installation of major steel bridge structure arch rib of Wuxi Xingtang Bridge,the essay introduces arch rib fabrication scheme,welding technique,and installation scheme and so on,and describes the construction technology of new structure,which has accumulated experience for similar engineering construction.%结合无锡市兴塘大桥主桥钢结构拱肋制作,焊接和安装的特殊性,深入介绍了大桥主拱肋的制作方案、焊接工艺和安装方案等,通过对这种新型结构形式施工工艺的介绍,为同类工程施工积累了经验。

  19. A Bumpy Road and a Bridge too Far? An Analysis of the Realistic Bridging and Horizontal Construction Capabilities of the Canadian Military Engineers in the Force 2013 Structure

    Science.gov (United States)

    2012-05-17

    separate engineer specialty. Finally, in the longer term, a review of the need for an under - armour bridging capability and the purchase of...For example, the wheeled Cougar vehicle was an armoured vehicle, crew trainer replacement for the costly main battle tank. Despite their design...budgetary relationship resembled an image with the military holding a begging bowl hoping for donations for their overseas missions.15 The Canadian Army

  20. Modelling Blast Effects on a Reinforced Concrete Bridge

    Directory of Open Access Journals (Sweden)

    Markellos Andreou

    2016-01-01

    Full Text Available The detailed investigation of blast phenomena and their catastrophic effects on existing structures are the main objectives of the present paper. It is well known that blast phenomena may be characterized by significant complexity, often involving complicated wave propagation effects as well as distinguishable material behaviors. Considering the above and in an attempt to provide a simplified modelling approach for the simulation of blast effects, a novel procedure is presented herein based on well-established methodologies and common engineering practices. In the above framework, firstly, the “predominant” deformation shape of the structure is estimated based on elastic finite element simulations under blast loads and then the structural response of the system is evaluated as a result of common computational beam-element tools such as displacement-based pushover analysis. The proposed methodology provides an immediate first estimation of the structural behavior under blast loads, based on familiar engineering procedures. A two-span reinforced concrete bridge was thoroughly investigated and the results provide insightful information regarding the damage patterns and localization.

  1. Unmanned aerial vehicle acquisition of three-dimensional digital image correlation measurements for structural health monitoring of bridges

    Science.gov (United States)

    Reagan, Daniel; Sabato, Alessandro; Niezrecki, Christopher

    2017-04-01

    Civil engineering structures such as bridges, buildings, and tunnels continue to be used despite aging and deterioration well past their design life. In 2013, the American Society of Civil Engineers (ASCE) rated the state of the U.S. bridges as mediocre, despite the $12.8 billion USD annually invested. Traditional inspection and monitoring techniques may produce inconsistent results, are labor intensive and too time-consuming to be considered effective for large-scale monitoring. Therefore, new structural health monitoring systems must be developed that are automated, highly accurate, minimally invasive, and cost effective. Three-dimensional (3D) digital image correlation (DIC) systems possess the capability of extracting full-field strain, displacement, and geometry profiles. Furthermore, as this measurement technique is implemented within an Unmanned Aerial Vehicle (UAV) the capability to expedite the optical-based measurement process is increased as well as the infrastructure downtime being reduced. These resulting integrity maps of the structure of interest can be easily interpreted by trained personal. Within this paper, the feasibility of performing DIC measurements using a pair of cameras installed on a UAV is shown. Performance is validated with in-flight measurements. Also, full-field displacement monitoring, 3D measurement stitching, and 3D point-tracking techniques are employed in conjunction with 3D mapping and data management software. The results of these experiments show that the combination of autonomous flight with 3D DIC and other non-contact measurement systems provides a highly valuable and effective civil inspection platform.

  2. Development of a real-time bridge structural monitoring and warning system: a case study in Thailand

    Science.gov (United States)

    Khemapech, I.; Sansrimahachai, W.; Toachoodee, M.

    2017-04-01

    Regarded as one of the physical aspects under societal and civil development and evolution, engineering structure is required to support growth of the nation. It also impacts life quality and safety of the civilian. Despite of its own weight (dead load) and live load, structural members are also significantly affected by disaster and environment. Proper inspection and detection are thus crucial both during regular and unsafe events. An Enhanced Structural Health Monitoring System Using Stream Processing and Artificial Neural Network Techniques (SPANNeT) has been developed and is described in this paper. SPANNeT applies wireless sensor network, real-time data stream processing and artificial neural network based upon the measured bending strains. Major contributions include an effective, accurate and energy-aware data communication and damage detection of the engineering structure. Strain thresholds have been defined according to computer simulation results and the AASHTO (American Association of State Highway and Transportation Officials) LRFD (Load and Resistance Factor Design) Bridge Design specifications for launching several warning levels. SPANNeT has been tested and evaluated by means of computer-based simulation and on-site levels. According to the measurements, the observed maximum values are 25 to 30 microstrains during normal operation. The given protocol provided at least 90% of data communication reliability. SPANNeT is capable of real-time data report, monitoring and warning efficiently conforming to the predefined thresholds which can be adjusted regarding user's requirements and structural engineering characteristics.

  3. Hydrothermal Synthesis, Crystal Structure, and Characterization of a Novel Terbium(Ⅲ) Coordination Polymer Bridged by 5-Sulfoisophthalate Trivalent Anions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Hydrothermal reaction of terbium( Ⅲ ) chloride with 5-sulfoisophthalic acid monosodium salt and 1, 10-phenanthroline(phen) at 415 K resulted in the formation of a novel coordination polymer, [Tb(sip) (phen) (H2O)]n( sip = 5-sulfoisophthalate trivalent anion) with a three-dimensional network structure. Each centrosymmetrically related pair of terbium ions are linked by two sip anions, forming a binuclear unit, and each binuclear unit links to four adjacent tetranuclear units, extending a two-dimensional hybrid layer at crystallographic bc plane. On the other hand,every three-terbium ion is connected by three sip anions, generating a trinuclear ring, and the trinuclear ring connects six neighboring trinuclear rings to produce another two-dimensional layer at crystallographic ab plane. Moreover, each sip anion acts as a pentadentate bridge, interconnecting two different types of layers to yield a novel three-dimensional framework.

  4. OGLE-ing the Magellanic System: Three-Dimensional Structure of the Clouds and the Bridge Using Classical Cepheids

    Science.gov (United States)

    Jacyszyn-Dobrzeniecka, A. M.; Skowron, D. M.; Mróz, P.; Skowron, J.; Soszyński, I.; Udalski, A.; Pietrukowicz, P.; Kozłowski, S.; Wyrzykowski, Ł.; Poleski, R.; Pawlak, M.; Szymański, M. K.; Ulaczyk, K.

    2016-06-01

    We analyzed a sample of 9418 fundamental-mode and first-overtone classical Cepheids from the OGLE-IV Collection of Classical Cepheids. The distance to each Cepheid was calculated using the period-luminosity relation for the Wesenheit magnitude, fitted to our data. The classical Cepheids in the LMC are situated mainly in the bar and in the northern arm. The eastern part of the LMC is closer to us and the plane fit to the whole LMC sample yields the inclination i=24.°2 ±0.°7 and position angle P.A.=151.°4±1.°7. We redefined the LMC bar by extending it in the western direction and found no offset from the plane of the LMC contrary to previous studies. On the other hand, we found that the northern arm is offset from a plane by about -0.5 kpc, which was not observed before. The age distribution of the LMC Cepheids shows one maximum at about 100 Myr. We demonstrate that the SMC has a non-planar structure and can be described as an extended ellipsoid. We identified two large ellipsoidal off-axis structures in the SMC. The northern one is located closer to us and is younger, while the south-western is farther and older. The age distribution of the SMC Cepheids is bimodal with one maximum at 110 Myr, and another one at 220 Myr. Younger stars are located in the closer part of this galaxy while older ones are more distant. We classified nine Cepheids from our sample as Magellanic Bridge objects. These Cepheids show a large spread in three-dimensions although five of them form a connection between the Clouds. The closest one is closer than any of the LMC Cepheids, while the farthest one - farther than any SMC Cepheid. All but one Cepheids in the Magellanic Bridge are younger than 300 Myr. The oldest one can be associated with the SMC Wing.

  5. 太阳河大桥结构耐久性设计%Structural Durability Design for Taiyanghe River Bridge

    Institute of Scientific and Technical Information of China (English)

    应天益; 袁胜峰

    2014-01-01

    The Taiyanghe River Bridge are composed of a suspended cable-arch structure and a rigid-frame structure with oblique legs ,the former belongs to an elastically supported continuous girder with multiple supports and the latter is a rigid-frame system with V-shaped piers .The main girder is a prestressed concrete structure and the arch ribs are steel and concrete hybrid structures . Because the bridge is exposed in the marine environment ,its structural durability should be given top priority .Based on the existing durability design codes and other documents ,to increase the thickness of the concrete cover and the compactness of concrete are regarded as the fundamental measures in the concrete durability design .The load bearing capacity of the structure was opti-mized and the maintenance condition for the components was improved so as to reduce the impact of minor cracks on the durability of components .Mcreover ,a series of auxiliary measures ,such as using rust inhibitor ,concrete coatings and permeable formwork lining were taken as well .The steel structure is protected using the corrosion prevention technique ,and selectively using the heavy corrosion protection coatings and the thermal spraying composite coatings .Meanwhile ,to further ensure the durability of the structure ,specific requirements for construction technique and construction quality control of the bridge are proposed .%太阳河大桥由拱索支撑结构和斜腿刚构组成,其中拱索支撑结构为多支点弹性支撑连续梁,斜腿刚构部分为V形墩刚构体系,主梁为预应力混凝土结构,主拱为钢-混凝土混合结构。该桥位于近海环境,其结构耐久性问题突出,在现有的耐久性设计规范和其它文献资料的基础上,采取增加混凝土保护层厚度和密实性作为混凝土耐久性设计的根本措施,通过优化结构受力和改善构件养护条件来减小裂缝对构件耐久性的影响,并采取了阻锈剂、混凝

  6. Crystal Structure of a 4-Methyl-phenylacetylide-bridged PtⅡCuⅠ2 Heterotrinuclear Organometallic Complex

    Institute of Scientific and Technical Information of China (English)

    武梅梅; 陈忠宁

    2004-01-01

    The heterotrinuclear complex [PtCu2(μ-dppm)2(dmbpy)2(μ-η1,(2 C ≡ CPhCH3-4)2] (ClO4)2·1.5CH2Cl2 1 (dmbpy = 4,4‘-dimethyl-2,2'-bipyridine, dppm = bis(diphenylphosphino)meth- ane) has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic system, space group Pī with a = 12.9359(3), b = 14.3908(2), c = 15.2121(3) (A), α = 107.370(1), β = 93.539(1), γ = 108.207(1)o, V = 2529.59(8) (A)3, Mr = 2015.96, Z = 1, Dc = 1.323 g/cm3, F(000) = 1019, ((MoKα) = 2.042 mm-1, the final R = 0.0604 and wR = 0.1529 for 8002 observed reflections with I > 2σ(I). The 4-methylphenylacetylides are bonded to the PtII and CuI centers in η1 (σ) and η2 (π) coordination modes, respectively. The PtII atom is linked by one dppm bridge to adopt a square planar environment and CuI by one alkynyl ligand to assume a distorted tetrahedral geometry.

  7. Fine structure above a light bridge in the transition region and corona

    CERN Document Server

    Bharti, Lokesh

    2015-01-01

    We present the results of multi wavelength, co-spatial and near co-temporal observations of jets above a sunspot light bridge. The data were obtained with the Solar Optical Telescope (SOT) on board Hinode, the Interface Region Spectrograph (IRIS) and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO). Most of the jets in the Ca II H images show decreasing brightness with height while in the IRIS slit jaw images at 1330 \\AA~ jets show a bright leading edge. These jets show rising and falling motion as evident from the parabolic profile obtained from the time-distance diagram. The rising and falling speeds of the jets are similar. These jets show a coordinated behaviour between neighbouring jets moving jointly up and down. Some of the jets show a plasma ejection from the leading edge which is also hotter at the transition region (TR) and coronal temperatures . A Similar behaviour is seen in the AIA wave bands that suggests that jets above the LB reach up to the lower corona and ...

  8. Application of ANSYS in Structure Analysis of Loading Bridge%ANSYS在塔式起重机结构分析中的应用

    Institute of Scientific and Technical Information of China (English)

    陈斌

    2015-01-01

    Loading bridge is a kind of special mechanical and electrical equipment ,its structure is relatively complex,more and more workers begin to adopt the finite element method to analyze the structure of the loading bridge,which has been widely applied at present in the ANSYS finite element analysis software,can through the establishment of the finite element analysis model ,improve the test efficiency of loading bridge , so ANSYS software in the analysis of the structure of the loading bridge plays an important role.This paper discusses the composition and classification of loading bridge ,and then analyzes the functions and features of ANSYS software ,and finally discusses the application of ANSYS software in structure analysis of loading bridge.%塔式起重机是一种特殊的机电设备,其结构较为复杂,越来越多的工作人员开始采用有限元分析的方法对塔式起重机的结构进行分析。目前应用较为广泛的ANSYS有限元分析软件,可以通过有限元分析模型的建立,提升塔式起重机的检验效率,因此ANSYS软件在塔式起重机的结构分析中具有重要的作用。文章首先探讨塔式起重机的构成和分类,然后分析ANSYS软件的功能特点,最后探讨ANSYS软件在塔式起重机结构分析中的应用。

  9. Study on effects of environmental temperature on dynamic characteristics of Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    Miao Changqing; Chen Liang; Feng Zhaoxiang

    2011-01-01

    The dynamic characteristics of three-tower and two-span suspension bridge are analyzed at different global temperatures. An equivalent cable inner force method is proposed to consider temperature effects and to study the effects of environmental temperature on dynamic characteristics of Taizhou Yangtze River Bridge. The result demonstrates that the effects of temperature can not be neglected in static or dynamic analysis of Taizhou Yangtze River Bridge. The relationship between temperature and frequency is negative. The effects of temperature should be taken into account in experimental modal analysis of long-span bridges and damage identification.

  10. Structural monitoring and modal properties of a real time bridge and lab tests

    NARCIS (Netherlands)

    Veerman, R.P.; Koenders, E.A.B.

    2014-01-01

    For understanding the actual state of durability of concrete structures, it is important to know its response due to external loading. This response mainly depends on the actual structural and material properties of the structure, while loaded. Mechanical and chemical degradation are the main mechan

  11. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

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

  12. Statistical analysis of modal properties of a cable-stayed bridge through long-term structural health monitoring with wireless smart sensor networks

    Science.gov (United States)

    Asadollahi, Parisa; Li, Jian

    2016-04-01

    Understanding the dynamic behavior of complex structures such as long-span bridges requires dense deployment of sensors. Traditional wired sensor systems are generally expensive and time-consuming to install due to cabling. With wireless communication and on-board computation capabilities, wireless smart sensor networks have the advantages of being low cost, easy to deploy and maintain and therefore facilitate dense instrumentation for structural health monitoring. A long-term monitoring project was recently carried out for a cable-stayed bridge in South Korea with a dense array of 113 smart sensors, which feature the world's largest wireless smart sensor network for civil structural monitoring. This paper presents a comprehensive statistical analysis of the modal properties including natural frequencies, damping ratios and mode shapes of the monitored cable-stayed bridge. Data analyzed in this paper is composed of structural vibration signals monitored during a 12-month period under ambient excitations. The correlation between environmental temperature and the modal frequencies is also investigated. The results showed the long-term statistical structural behavior of the bridge, which serves as the basis for Bayesian statistical updating for the numerical model.

  13. The Akashi Kaikyo Bridge and the Storebælt Bridge

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

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

  14. Modular FRP Composite Bridge Deck

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The bridge infrastructure of the United States is in constant need of repair and rehabilitation. It is reported that 43% of the bridges in the USA have been identified as being structurally deficient or functionally obsolete due to corrosion. SuperdeckTM, a non-corrosive fiber reinforced polymer (FRP) composite bridge deck. The Deck is designed and engineered into a lightweight, strong and rigid structure that will not corrode. The deck sections, composed of hexagon and double-trapezoid profi...

  15. Development of cooperative system bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; WAN Qi-bai; SHI Lei

    2008-01-01

    Cooperative system bridges comprise several basic structures that act jointly to improve structural characteristics. We delved into the historical development of cooperative system bridges. Cooperative systems are classified as different-load cooperative systems and same-load cooperative systems by distinguishing the modes of load distribution. For different-load cooperation, individual basic structures are at different positions in the direction along bridge axis and carry the loads separately. While for same-load cooperation, all basic structures overlap in geometrical locations and support the entire loads conjointly. The choosing of span ratios between basic structures, the design of connections of different-load cooperative systems were discussed as well as optimizations of relative rigidity for same-load cooperative systems which greatly influence structural characteristics. The general situation and several structural measurements of several cooperative bridges were demonstrated. This information can assist engineers in developing their concepts in cooperative systems and can lead to more efficient and economical cooperative bridges.

  16. Bridging the information gap: computational tools for intermediate resolution structure interpretation.

    Science.gov (United States)

    Jiang, W; Baker, M L; Ludtke, S J; Chiu, W

    2001-05-18

    Due to large sizes and complex nature, few large macromolecular complexes have been solved to atomic resolution. This has lead to an under-representation of these structures, which are composed of novel and/or homologous folds, in the library of known structures and folds. While it is often difficult to achieve a high-resolution model for these structures, X-ray crystallography and electron cryomicroscopy are capable of determining structures of large assemblies at low to intermediate resolutions. To aid in the interpretation and analysis of such structures, we have developed two programs: helixhunter and foldhunter. Helixhunter is capable of reliably identifying helix position, orientation and length using a five-dimensional cross-correlation search of a three-dimensional density map followed by feature extraction. Helixhunter's results can in turn be used to probe a library of secondary structure elements derived from the structures in the Protein Data Bank (PDB). From this analysis, it is then possible to identify potential homologous folds or suggest novel folds based on the arrangement of alpha helix elements, resulting in a structure-based recognition of folds containing alpha helices. Foldhunter uses a six-dimensional cross-correlation search allowing a probe structure to be fitted within a region or component of a target structure. The structural fitting therefore provides a quantitative means to further examine the architecture and organization of large, complex assemblies. These two methods have been successfully tested with simulated structures modeled from the PDB at resolutions between 6 and 12 A. With the integration of helixhunter and foldhunter into sequence and structural informatics techniques, we have the potential to deduce or confirm known or novel folds in domains or components within large complexes.

  17. Dynamic Bridge Response for a Bridge-friendly Truck

    Directory of Open Access Journals (Sweden)

    V. Šmilauer

    2004-01-01

    Full Text Available A truck with controlled semi-active suspensions traversing a bridge is examined for benefits to the bridge structure. The original concept of a road-friendly truck was extended to a bridge-friendly vehicle, using the same optimization tools. A half-car model with two independently driven axles is coupled with simply supported bridges (beam, slab model with the span range from 5 m to 50 m. Surface profile of the bridge deck is either stochastic or in the shape of a bump or a pot in the mid-span. Numerical integration in the MATLAB/SIMULINK environment solves coupled dynamic equations of motion with optimized truck suspensions. The rear axle generates the prevailing load and to a great extent determines the bridge response. A significant decrease in contact road-tire forces is observed and the mid-span bridge deflections are on average smaller, when compared to commercial passive suspensions. 

  18. Mixed-valent metals bridged by a radical ligand: fact or fiction based on structure-oxidation state correlations.

    Science.gov (United States)

    Sarkar, Biprajit; Patra, Srikanta; Fiedler, Jan; Sunoj, Raghavan B; Janardanan, Deepa; Lahiri, Goutam Kumar; Kaim, Wolfgang

    2008-03-19

    Electron-rich Ru(acac)2 (acac- = 2,4-pentanedionato) binds to the pi electron-deficient bis-chelate ligands L, L = 2,2'-azobispyridine (abpy) or azobis(5-chloropyrimidine) (abcp), with considerable transfer of negative charge. The compounds studied, (abpy)Ru(acac)2 (1), meso-(mu-abpy)[Ru(acac)2]2 (2), rac-(mu-abpy)[Ru(acac)2]2 (3), and (mu-abcp)[Ru(acac)2]2 (4), were calculated by DFT to assess the degree of this metal-to-ligand electron shift. The calculated and experimental structures of 2 and 3 both yield about 1.35 A for the length of the central N-N bond which suggests a monoanion character of the bridging ligand. The NBO analysis confirms this interpretation, and TD-DFT calculations reproduce the observed intense long-wavelength absorptions. While mononuclear 1 is calculated with a lower net ruthenium-to-abpy charge shift as illustrated by the computed 1.30 A for d(N-N), compound 4 with the stronger pi accepting abcp bridge is calculated with a slightly lengthened N-N distance relative to that of 2. The formulation of the dinuclear systems with monoanionic bridging ligands implies an obviously valence-averaged Ru(III)Ru(II) mixed-valent state for the neutral molecules. Mixed valency in conjunction with an anion radical bridging ligand had been discussed before in the discussion of MLCT excited states of symmetrically dinuclear coordination compounds. Whereas 1 still exhibits a conventional electrochemical and spectroelectrochemical behavior with metal centered oxidation and two ligand-based one-electron reduction waves, the two one-electron oxidation and two one-electron reduction processes for each of the dinuclear compounds Ru2.5(L*-)Ru2.5 reveal more unusual features via EPR and UV-vis-NIR spectroelectrochemistry. In spite of intense near-infrared absorptions, the EPR results show that the first reduction leads to Ru(II)(L*-)Ru(II) species, with an increased metal contribution for system 4*-. The second reduction to Ru(II)(L2-)Ru(II) causes the

  19. A Fault-Tolerant Parallel Structure of Single-Phase Full-Bridge Rectifiers for a Wound-Field Doubly Salient Generator

    DEFF Research Database (Denmark)

    Chen, Zhihui; Chen, Ran; Chen, Zhe

    2013-01-01

    The fault-tolerance design is widely adopted for high-reliability applications. In this paper, a parallel structure of single-phase full-bridge rectifiers (FBRs) (PS-SPFBR) is proposed for a wound-field doubly salient generator. The analysis shows the potential fault-tolerance capability of the P...

  20. Structure-Based Design of a Novel SMYD3 Inhibitor that Bridges the SAM-and MEKK2-Binding Pockets.

    Science.gov (United States)

    Van Aller, Glenn S; Graves, Alan P; Elkins, Patricia A; Bonnette, William G; McDevitt, Patrick J; Zappacosta, Francesca; Annan, Roland S; Dean, Tony W; Su, Dai-Shi; Carpenter, Christopher L; Mohammad, Helai P; Kruger, Ryan G

    2016-05-03

    SMYD3 is a lysine methyltransferase overexpressed in colorectal, breast, prostate, and hepatocellular tumors, and has been implicated as an oncogene in human malignancies. Methylation of MEKK2 by SMYD3 is important for regulation of the MEK/ERK pathway, suggesting the possibility of selectively targeting SMYD3 in RAS-driven cancers. Structural and kinetic characterization of SMYD3 was undertaken leading to a co-crystal structure of SMYD3 with a MEKK2-peptide substrate bound, and the observation that SMYD3 follows a partially processive mechanism. These insights allowed for the design of GSK2807, a potent and selective, SAM-competitive inhibitor of SMYD3 (Ki = 14 nM). A high-resolution crystal structure reveals that GSK2807 bridges the gap between the SAM-binding pocket and the substrate lysine tunnel of SMYD3. Taken together, our data demonstrate that small-molecule inhibitors of SMYD3 can be designed to prevent methylation of MEKK2 and these could have potential use as anticancer therapeutics.

  1. Crystal structure of the HSV-1 Fc receptor bound to Fc reveals a mechanism for antibody bipolar bridging.

    Directory of Open Access Journals (Sweden)

    Elizabeth R Sprague

    2006-06-01

    Full Text Available Herpes simplex virus type-1 expresses a heterodimeric Fc receptor, gE-gI, on the surfaces of virions and infected cells that binds the Fc region of host immunoglobulin G and is implicated in the cell-to-cell spread of virus. gE-gI binds immunoglobulin G at the basic pH of the cell surface and releases it at the acidic pH of lysosomes, consistent with a role in facilitating the degradation of antiviral antibodies. Here we identify the C-terminal domain of the gE ectodomain (CgE as the minimal Fc-binding domain and present a 1.78-angstroms CgE structure. A 5-angstroms gE-gI/Fc crystal structure, which was independently verified by a theoretical prediction method, reveals that CgE binds Fc at the C(H2-C(H3 interface, the binding site for several mammalian and bacterial Fc-binding proteins. The structure identifies interface histidines that may confer pH-dependent binding and regions of CgE implicated in cell-to-cell spread of virus. The ternary organization of the gE-gI/Fc complex is compatible with antibody bipolar bridging, which can interfere with the antiviral immune response.

  2. Routes to new hafnium(IV) tetraaryl porphyrins and crystal structures of unusual phosphate-, sulfate-, and peroxide-bridged dimers.

    Science.gov (United States)

    Falber, Alexander; Todaro, Louis; Goldberg, Israel; Favilla, Michael V; Drain, Charles Michael

    2008-01-21

    New routes for the synthesis of mono tetraaryl porphyrinato hafnium(IV) complexes, Hf(IV)Por(L)(2), are reported, where the secondary ligands, L, are determined by the method of purification. These synthetic routes cater to the solubility of the macrocycles and provide access to Hf(IV) complexes of meso tetraaryl porphyrins bearing diverse functional groups such as phenyl, tolyl, pyridyl, pentafluorophenyl, and carboxyphenyl. The latter three derivatives significantly expand the repertoire of hafnium porphyrinates. One route refluxes the porphyrin with HfCl(4) in 1-chloronaphthalene or in a mixed solvent of 1-chloronaphthalene and o-cresol. A second, solventless method is also reported wherein the porphyrin is mixed with Hf(cp)(2)Cl(2) and heated to give the metalated porphyrin in good yields. Simultaneous purification and formation of stable porphyrinato hafnium(IV) diacetate complexes, Hf(Por)OAc(2), is accomplished by elution over silica gel using 3-5% acetic acid in the eluent. Exchange of the acetate ligands for other oxo-bearing ligands can be nearly quantitative, such as p-aminobenzoate (PABA), pentanoate (pent), or octanoate (oct). Notably, we find that two to three of a variety of small multitopic dianions such as peroxo (O(2)(-2)), SO(4)(-2), and HPO(4)(-2) serve to bridge between two Hf(Por) moieties to form stable dimers. The crystal structures of this library of Hf(Por) complexes are reported, and we note that careful analysis of crystallography data reveals (Por)Hf(micro-eta(2)-O(2))(2)Hf(Por) rather than four bridging oxo or hydroxy ions.

  3. Significant manipulation of output performance of a bridge-structured spin valve magnetoresistance sensor via an electric field

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yue; Yan, Baiqian; Ou-Yang, Jun; Zhu, Benpeng; Chen, Shi; Yang, Xiaofei, E-mail: hust-yangxiaofei@163.com [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wang, Xianghao [School of Information Engineering, Wuhan University of Technology, Wuhan 430070 (China)

    2016-01-28

    Through principles of spin-valve giant magnetoresistance (SV-GMR) effect and its application in magnetic sensors, we have investigated electric-field control of the output performance of a bridge-structured Co/Cu/NiFe/IrMn SV-GMR sensor on a PZN-PT piezoelectric substrate using the micro-magnetic simulation. We centered on the influence of the variation of uniaxial magnetic anisotropy constant (K) of Co on the output of the bridge, and K was manipulated via the stress of Co, which is generated from the strain of a piezoelectric substrate under an electric field. The results indicate that when K varies between 2 × 10{sup 4 }J/m{sup 3} and 10 × 10{sup 4 }J/m{sup 3}, the output performance can be significantly manipulated: The linear range alters from between −330 Oe and 330 Oe to between −650 Oe and 650 Oe, and the sensitivity is tuned by almost 7 times, making it possible to measure magnetic fields with very different ranges. According to the converse piezoelectric effect, we have found that this variation of K can be realized by applying an electric field with the magnitude of about 2–20 kV/cm on a PZN-PT piezoelectric substrate, which is realistic in application. This result means that electric-control of SV-GMR effect has potential application in developing SV-GMR sensors with improved performance.

  4. Structural Design of Multi-Pylon Cable-Stayed Bridge with Corrugated Steel Webs for Chaoyang Bridge in Nanchang%南昌朝阳大桥波形钢腹板多塔斜拉桥结构设计

    Institute of Scientific and Technical Information of China (English)

    陈水生; 钟志斌; 桂水荣; 刘旭政; 钟汉清

    2014-01-01

    The PC composite box girder with corrugated steel webs is applicable to bridges with a variety of structural types ,which exhibits superior durability and economic features as com‐pared with the common concrete box girder .The cable‐stayed bridge with corrugated steel webs is regarded as the type of structure where composite box girder with corrugated steel webs is ingen‐iously used ,making better use of the properties of the two structures . The main navigational bridge of the Chaoyang Bridge in Nanchang is a (79+ 5 × 150+79) m continuous composite box girder cable‐stayed bridge with corrugated steel webs .The bridge has six pylons and the stay ca‐bles are arranged in single cable plane .In addition ,the bridge has two layers of decks ,on the up‐per deck ,dual eight vehicle lanes (four lanes each side) are arranged and pedestrian and non‐mo‐torized vehicle lanes are arranged on the lower deck .Based on the analysis and study undertaken , small side span‐to‐main span ratio was chosen .Due to the multiple pylons ,the load path from the intermediate pylons to the side pylons is long and the effect of ancillary piers in the side spans is minimal ,as a result ,no ancillary piers are installed .In the structural system ,the pylons and the main girder are fixed while the girder and piers are separated .The box girder is 43 .84 m wide , with transverse steel diaphragms .The stay cables are fanned out in single cable plane .The pylon looks like the Chinese character“合“ ,and double bearings are installed at the pylons .T he stay vi‐bration mitigation bearings are used as the vibration mitigation and isolation devices of the super‐structure ,which are installed below the two side pylons .%波形钢腹板PC组合箱梁适用于不同结构形式的桥梁,相比普通混凝土箱梁具有显著的耐久性和经济性,波形钢腹板斜拉桥将波形钢腹板组合箱梁应用到斜拉桥中,充分发挥了2种结构的特点。南昌朝

  5. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

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

    2012-01-01

    Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also...... endangered people safety in few cases. Purpose of this paper is making a focus on the state of the art of the research and current regulations concerning the response of bridges to fire. Several cases of bridge fires are reported and a focus is made on the occurrence and consequence of bridge fires......, considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  6. A Bridging Cell Multiscale Methodology to Model the Structural Behaviour of Polymer Matrix Composites

    Science.gov (United States)

    Iacobellis, Vincent

    Composite and nanocomposite materials exhibit behaviour which is inherently multiscale, extending from the atomistic to continuum levels. In composites, damage growth tends to occur at the nano and microstructural scale by means of crack growth and fibre-matrix debonding. Concurrent multiscale modeling provides a means of efficiently solving such localized phenomena, however its use in this application has been limited due to a number of existing issues in the multiscale field. These include the seamless transfer of information between continuum and atomistic domains, the small timesteps required for dynamic simulation, and limited research into concurrent multiscale modeling of amorphous polymeric materials. The objective of this thesis is thus twofold: to formulate a generalized approach to solving a coupled atomistic-to-continuum system that addresses these issues and to extend the application space of concurrent multiscale modeling to damage modeling in composite microstructures. To achieve these objectives, a finite element based multiscale technique termed the Bridging Cell Method (BCM), has been formulated with a focus on crystalline material systems. Case studies are then presented that show the effectiveness of the developed technique with respect to full atomistic simulations. The BCM is also demonstrated for applications of stress around a nanovoid, nanoindentation, and crack growth due to monotonic and cyclic loading. Next, the BCM is extended to modeling amorphous polymeric material systems where an adaptive solver and a two-step iterative solution algorithm are introduced. Finally, the amorphous and crystalline BCM is applied to modeling a polymer-graphite interface. This interface model is used to obtain cohesive zone parameters which are used in a cohesive zone model of fibre-matrix interfacial cracking in a composite microstructure. This allows for an investigation of the temperature dependent damage mechanics from the nano to microscale within

  7. An all-atom structure-based potential for proteins: bridging minimal models with all-atom empirical forcefields.

    Science.gov (United States)

    Whitford, Paul C; Noel, Jeffrey K; Gosavi, Shachi; Schug, Alexander; Sanbonmatsu, Kevin Y; Onuchic, José N

    2009-05-01

    Protein dynamics take place on many time and length scales. Coarse-grained structure-based (Go) models utilize the funneled energy landscape theory of protein folding to provide an understanding of both long time and long length scale dynamics. All-atom empirical forcefields with explicit solvent can elucidate our understanding of short time dynamics with high energetic and structural resolution. Thus, structure-based models with atomic details included can be used to bridge our understanding between these two approaches. We report on the robustness of folding mechanisms in one such all-atom model. Results for the B domain of Protein A, the SH3 domain of C-Src Kinase, and Chymotrypsin Inhibitor 2 are reported. The interplay between side chain packing and backbone folding is explored. We also compare this model to a C(alpha) structure-based model and an all-atom empirical forcefield. Key findings include: (1) backbone collapse is accompanied by partial side chain packing in a cooperative transition and residual side chain packing occurs gradually with decreasing temperature, (2) folding mechanisms are robust to variations of the energetic parameters, (3) protein folding free-energy barriers can be manipulated through parametric modifications, (4) the global folding mechanisms in a C(alpha) model and the all-atom model agree, although differences can be attributed to energetic heterogeneity in the all-atom model, and (5) proline residues have significant effects on folding mechanisms, independent of isomerization effects. Because this structure-based model has atomic resolution, this work lays the foundation for future studies to probe the contributions of specific energetic factors on protein folding and function.

  8. WebDat: bridging the gap between unstructured and structured data

    Energy Technology Data Exchange (ETDEWEB)

    Nogiec, Jerzy M.; Trombly-Freytag, Kelley; Carcagno, Ruben; /Fermilab

    2008-11-01

    Accelerator R&D environments produce data characterized by different levels of organization. Whereas some systems produce repetitively predictable and standardized structured data, others may produce data of unknown or changing structure. In addition, structured data, typically sets of numeric values, are frequently logically connected with unstructured content (e.g., images, graphs, comments). Despite these different characteristics, a coherent, organized and integrated view of all information is sought out. WebDat is a system conceived as a result of efforts in this direction. It provides a uniform and searchable view of structured and unstructured data via common metadata, regardless of the repository used (DBMS or file system). It also allows for processing data and creating interactive reports. WebDat supports metadata management, administration, data and content access, application integration via Web services, and Web-based collaborative analysis.

  9. MP2, CCSD(T), and Density Functional Theory Study of the 2-Butyl Cation: New Insight into the Methyl- and Hydrogen-Bridged Structures.

    Science.gov (United States)

    Rasul, Golam; Prakash, G K Surya; Olah, George A

    2015-06-04

    Using the MP2, CCSD(T), and DFT (B3LYP) methods, the structures and energies of the 2-butyl cation (C4H9(+)) were calculated. Energetically, the C-C hyperconjugated structure 1 and hydrogen-bridged structure 2 were found to be almost identical at all levels. The (13)C NMR chemical shifts of 1 and 2 were computed by the GIAO-CCSD(T) method using different geometries. On the basis of calculated relative energies and calculated (13)C NMR chemical shifts, an equilibrium involving 1 and 2 (in a 50:50 ratio) seemed likely responsible for the experimentally observed (13)C NMR chemical shifts in superacid solutions at -80 °C. However, on the basis of computed and experimental frequencies the hydrogen-bridged structure 2 is most likely responsible for the experimentally observed frequencies in the solid state at -125 °C.

  10. Synthesis and Crystal Structure of a Dinuclear Cu(II) Complex with Tridentate Schiff Base and Azido Bridge

    Institute of Scientific and Technical Information of China (English)

    LIN Hong; FENG Yun Long; GAO Shan

    2005-01-01

    A new dinuclear copper(II) complex ([Cu(C12H17N2O)(N3)]2, C24H34Cu2N10O2) has been synthesized and characterized by X-ray structure determination. It crystallizes in the monoclinic system, space group P21/c with a = 18.529(4), b = 10.933(2), c = 14.534(3)(A),β = 111.07(3)(A), V = 2748(1)(A)3, Z = 4, Mr = 621.69, F(000) = 1288, Dc = 1.503 g/cm3 and μ(MoKα) = 1.590 mm(1. The structure was refined to R = 0.0647 and wR = 0.1846 for 4406 observed reflections (I > 2σ(I)). The asymmetric unit comprises two halfmolecules. The complex is a centrosymmetric dimmer in which the copper atoms are penta-coordinated by three coordination atoms from the corresponding tridentate Schiff base ligand and two bridging azide anions. The Cu(II)…Cu(II) average distance is 3.350(1)(A).

  11. Octazethrene and Its Isomer with Different Diradical Characters and Chemical Reactivity: The Role of the Bridge Structure.

    Science.gov (United States)

    Hu, Pan; Lee, Sangsu; Park, Kyu Hyung; Das, Soumyajit; Herng, Tun Seng; Gonçalves, Théo P; Huang, Kuo-Wei; Ding, Jun; Kim, Dongho; Wu, Jishan

    2016-04-01

    The fundamental relationship between structure and diradical character is important for the development of open-shell diradicaloid-based materials. In this work, we synthesized two structural isomers bearing a 2,6-naphthoquinodimethane or a 1,5-naphthoquinodimethane bridge and demonstrated that their diradical characters and chemical reactivity are quite different. The mesityl-or pentafluorophenyl-substituted octazethrene derivatives OZ-M/OZ-F and their isomer OZI-M (with mesityl substituents) were synthesized via an intramolecular Friedel-Crafts alkylation followed by oxidative dehydrogenation strategy from the key building blocks 4 and 11. Our detailed experimental and theoretical studies showed that both isomers have an open-shell singlet ground state with a remarkable diradical character (y0 = 0.35 and 0.34 for OZ-M and OZ-F, and y0 = 0.58 for OZI-M). Compounds OZ-M and OZ-F have good stability in an ambient environment, while OZI-M has high reactivity and can be easily oxidized to a dioxo product 15, which can be correlated to their different diradical characters. Additionally, we investigated the physical properties of OZ-M, OZ-F, and 15.

  12. Octazethrene and Its Isomer with Different Diradical Characters and Chemical Reactivity: The Role of the Bridge Structure

    KAUST Repository

    Hu, Pan

    2016-03-11

    The fundamental relationship between structure and diradical character is important for the development of open-shell diradicaloid-based materials. In this work, we synthesized two structural isomers bearing a 2,6-naphthoquinodimethane or a 1,5-naphthoquinodimethane bridge and demonstrated that their diradical characters and chemical reactivity are quite different. The mesityl or pentafluorophenyl substituted octazethrene derivatives OZ-M/OZ-F and their isomer OZI-M (with mesityl substituents) were synthesized via an intramolecular Friedel-Crafts alkylation followed by oxidative dehydrogenation strategy from the key building blocks 4 and 11. Our detailed experimental and theoretical studies showed that both isomers have an open-shell singlet ground state with a remarkable diradical character (y0 = 0.35 and 0.34 for OZ-M and OZ-F, and y0 = 0.58 for OZI-M). Compounds OZ-M and OZ-F have good stability under the ambient environment while OZI-M has high reactivity and can be easily oxidized to a dioxo-product 15, which can be correlated to their different diradical characters. Additionally, we investigated the physical properties of OZ-M, OZ-F and 15.

  13. Research on dynamic characteristics model test scheme for middle pylon of multi-pylon multi-span suspension bridges

    Institute of Scientific and Technical Information of China (English)

    Zhang Yufeng; Zhang Dachang

    2012-01-01

    Multi-pylon multi-span suspension bridge is a new type super flexible structure system, and the rigidity design of middle pylon is one of the main difficult technical issues. Due to the requirements of longitudinal rigidity, the structural form and the corresponding foundation type of middle pylon are different from those of the ordinary steel pylon, and the complicated dynamic characteristics make the calculation quite difficult. In this article, exploration has been made in selection of similarity ratio and model materials, section simulation, restriction conditions simulation, fixing of mass blocks, fabrication scheme and testing method by taking into account different construction and working conditions such as restriction conditions and working environment of a three-pylon suspension bridge, to conduct the test experimental design of the dynamic behavior of the middle pylon, with the purpose to reveal its dynamic characteristics and make comparison and analysis with theoretical assumptions, to provide basis for anti-wind and anti-seismic design and reference for the design and research of three-pylon two-span suspension bridges in the future.

  14. Corrigendum to "Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate" [J. Mol. Struct. 1093 (2015) 135-143

    Science.gov (United States)

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

    2017-04-01

    The authors regret to inform that Scheme 1 in the article titled 'Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate' in vol. 1093 of the Journal of Molecular Structure is incorrect. The corrected scheme is as shown in this correction. This is purely a copy error. The error does not affect the conclusion in paper. The authors would like to apologize for any inconvenience caused.

  15. Metal-Organic Frameworks with d-f Cyanide Bridges: Structural Diversity, Bonding Regime, and Magnetism

    NARCIS (Netherlands)

    Ferbinteanu, M.; Cimpoesu, F.; Tanase, S.; Cheng, P.

    2015-01-01

    We present a selection of metal-organic frameworks based on d-f and f-f linkages, discussing their structural features and properties from experimental and theoretical viewpoints. We give an overview of our own synthetic and modeling methodologies, highlighting the complexity of the

  16. Metal-Organic Frameworks with d-f Cyanide Bridges: Structural Diversity, Bonding Regime, and Magnetism

    NARCIS (Netherlands)

    M. Ferbinteanu; F. Cimpoesu; S. Tanase

    2015-01-01

    We present a selection of metal-organic frameworks based on d-f and f-f linkages, discussing their structural features and properties from experimental and theoretical viewpoints. We give an overview of our own synthetic and modeling methodologies, highlighting the complexity of the interdisciplinar

  17. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

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

  18. System identification of civil engineering structures with multiple inputs by decoupling output signals

    Science.gov (United States)

    Li, Jian; Ruiz-Sandoval, Manuel; Spencer, Billie F.; Elnashai, Amr S.

    2014-03-01

    System identification of civil engineering structures are often formulated as Multiple-Input, Multiple-Output (MIMO) problems due to the complexity of loading conditions such as differential ground motion, which is also multi-directional in nature. Such MIMO system identification problems are challenging due to strong coupling between the contributions of multiple ground motion inputs to each individual response. Compared with Single-Input, Multiple-Output (SIMO) system identification, MIMO problems are often more computationally complex and error prone. In this paper, a new system identification strategy is proposed in which a more complex MIMO problem is converted into a number of SIMO problems by decoupling the contribution of multiple inputs to the outputs. A QR-factorization based approach is adopted for the decoupling and its accuracy is investigated. The effectiveness of the proposed strategy is demonstrated through applications to a two-span straight bridge and a four-span curved bridge, both are highway bridges.

  19. Structural performance of complex core systems for FRP-balsa composite sandwich bridge decks

    OpenAIRE

    Osei-Antwi, Michael

    2014-01-01

    Based on current fiber-reinforced polymer (FRP) composite construction principles, FRP decks fall into two categories: pultruded decks and sandwich decks. Sandwich decks comprise face sheets and either honeycombs or foams reinforced with internal FRP webs for shear resistance. The honeycomb structure and the webs cause debonding between the upper face sheets and the core due to the uneven support of the former. An alternative material that has high shear capacity and can provide uniform ...

  20. Evol and ProDy for bridging protein sequence evolution and structural dynamics

    OpenAIRE

    Bakan, Ahmet; Dutta, Anindita; Mao, Wenzhi; Liu, Ying; Chennubhotla, Chakra; Lezon, Timothy R.; Bahar, Ivet

    2014-01-01

    Correlations between sequence evolution and structural dynamics are of utmost importance in understanding the molecular mechanisms of function and their evolution. We have integrated Evol, a new package for fast and efficient comparative analysis of evolutionary patterns and conformational dynamics, into ProDy, a computational toolbox designed for inferring protein dynamics from experimental and theoretical data. Using information-theoretic approaches, Evol coanalyzes conservation and coevolu...

  1. 23 CFR 650.807 - Bridges requiring a USCG permit.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Bridges requiring a USCG permit. 650.807 Section 650.807... BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.807 Bridges requiring a USCG... improvement or construction of a bridge over navigable waters except for the exemption exercised by FHWA...

  2. Structural, spectroscopic, and reactivity comparison of xanthene- and dibenzofuran-bridged cofacial bisporphyrins.

    Science.gov (United States)

    Chang, Christopher J; Baker, Erin A; Pistorio, Bradford J; Deng, Yongqi; Loh, Zhi-Heng; Miller, Scott E; Carpenter, Scott D; Nocera, Daniel G

    2002-06-17

    A comparison of the structure, spectroscopy, and oxygen atom-transfer reactivity of cofacial bisporphyrins anchored by xanthene (DPX) and dibenzofuran (DPD) pillars is presented. The synthesis and characterization of dicopper(II) and dinickel(II) complexes of DPD completes a homologous series of homobimetallic zinc(II), copper(II), and nickel(II) complexes for both cofacial platforms. X-ray crystallographic analysis of the parent free-base porphyrins H(4)DPX (1) and H(4)DPD (5) confirms the face-to-face arrangement of the two porphyrin macrocycles with a large available range of vertical pocket sizes: 1 (C(80)H(92)Cl(2)N(8)O), triclinic, space group P1 macro, a = 13.5167(12) A, b = 21.7008(18) A, c = 23.808(2) A, alpha = 80.116(2) degrees, beta = 76.832(2) degrees, gamma = 80.4070(10) degrees, Z = 4; 5 (C(80)H(83)N(8)O(2)), monoclinic, space group C2/c, a = 22.666(2) A, b = 13.6749(14) A, c = 42.084(4) A, beta = 94.554(2) degrees, Z = 8. EPR spectroscopy of dicopper(II) derivatives Cu(2)DPX (3) and Cu(2)DPD (7) complements the crystallographic studies by probing intramolecular metal-metal arrangements in frozen solution. Exciton interactions between the porphyrin subunits in fluid solution are revealed by steady-state and time-resolved electronic absorption and emission spectroscopy. The resulting compilation of structural and spectroscopic data provides a benchmark for the use of these and related platforms for the activation of small-molecule substrates. A structure-function relation is developed for the photoinduced oxygen atom-transfer reactions of bisiron(III) mu-oxo derivatives of DPX and DPD. The efficiency of the photochemical process is markedly dependent (approximately 10(4)-fold) on the vertical flexibility of cofacial architecture provided by the spacer.

  3. Evol and ProDy for bridging protein sequence evolution and structural dynamics

    Science.gov (United States)

    Mao, Wenzhi; Liu, Ying; Chennubhotla, Chakra; Lezon, Timothy R.; Bahar, Ivet

    2014-01-01

    Correlations between sequence evolution and structural dynamics are of utmost importance in understanding the molecular mechanisms of function and their evolution. We have integrated Evol, a new package for fast and efficient comparative analysis of evolutionary patterns and conformational dynamics, into ProDy, a computational toolbox designed for inferring protein dynamics from experimental and theoretical data. Using information-theoretic approaches, Evol coanalyzes conservation and coevolution profiles extracted from multiple sequence alignments of protein families with their inferred dynamics. Availability and implementation: ProDy and Evol are open-source and freely available under MIT License from http://prody.csb.pitt.edu/. Contact: bahar@pitt.edu PMID:24849577

  4. Weigh-in-motion and smart bridges

    Science.gov (United States)

    Lai, Leon L.

    1997-05-01

    The bridge Weigh-In-Motion (WIM) system uses bridge structures as weigh scales to measure axle and gross vehicle weights and vehicle configurations without stopping or detouring the vehicles. Because the system is mobile and is almost invisible to the truck drivers, it can be used to collect unbiased traffic data for transportation and loadometer study. The WIM + RESPONSE system, which is an expansion of the original WIM system, was developed to collect additional bridge response data and perform bridge structural evaluation. These additional bridge response data provide bridge engineers with information necessary for improving bridge design and evaluation procedures. Bridge health monitoring and damage detection may also be conducted with long term installation of the WIM + RESPONSE system. This paper discusses what has been achieved by the WIM + RESPONSE system and how the system can be further improved to enhance its functions in a smart bridge.

  5. Carboxylate-bridged Cu(II) coordination polymeric complex: synthesis, crystal structure, magnetic properties, DNA binding and electrochemical studies

    Indian Academy of Sciences (India)

    SABITHAKALA THATITURI; BHARGAVI GOVINDUGARI; VENKATA RAMANA REDDY CHITTIREDDY

    2017-08-01

    A novel water-soluble carboxylate-bridged copper(II) coordination polymer,Cu-BIG was formed by the reaction of Cu(ClO₄)₂ ·6H₂O and tridentate benzimidazole-glycine conjugate ligand, 2-((1H-benzimidazol- 2-yl)methylamino) acetic acid, BIGH and its structure has been determined by IR, UV, powder XRD, VSM, CV, TGA, DTA, EPR and single crystal X-ray diffraction. Crystallographic studies indicate it to be a coordination polymer with P¯ı Space group. The asymmetric unit of complex contains two Cu(II) ions with elongated square pyramid geometry.The axial positions of theCu(II) atoms are occupied by the carbonyl oxygen of the carboxylate group with the bond distances Cu(1)–O(5)axial , 2.28Å, and Cu(2)–O(2)axial , 2.26Å. The two Cu(II) are connected through the carboxylic group present in BIGH, which provides electron mobilisation in the molecule and hence results in the soft ferromagnetic polymer. An in vitro antibacterial activity study of BIGH and Cu-BIG showed moderate activity against Bacillus subtilis. The DNA binding studies showed the interaction of Cu-BIG with CT-DNA.

  6. Preparation, Crystal Structure and Properties of a Pentametallic 3-Ferrocenyl-2-crotonic acid-Bridged Copper(Ⅱ) Complex

    Institute of Scientific and Technical Information of China (English)

    杨家祥; 张泽; 吴杰颖; 田玉鹏; 刘清亮; FUN,HoongKun; USMAN,Anwar; 许志强; LAURENCE,K.Thompson

    2003-01-01

    The synthesis and characterization of the copper(ll) complex[ Cu2 ( OOCCH = C (CH3) Fc )3 ( phen ) 2 ] ClO4·2H2O ( 1 ) are reported. The structure of the complex was determined by singlecrystal X-ray analysis. The compound crystallizes in the monoclinic system, space group Pc, with Z = 2, a = 1.2799(4) nm,b =0.9969(4) nm, c = 2.5228 nm, and β = 91.576(1)°. The cationic part of 1 indicates a penametallic core in which three 3-ferrocenyl-2-crotonic acid salt (FCA) groups act as (O, O'') bridging ligands between two copper(II) ions with a squarepyramidal environment. Cyclic voltammetric experiments in acetonitrile have been performed mainly to examine the Fe(Ⅱ)→Fe(Ⅲ) one-electron oxidation in FCA and its complex. The variable-temperature magnetic susceptibility measurements re-vealed very weak intramolecular anti-ferromagnetic coupling.Fitting parameters are 2J = -0.2 cm-1, g = 2.114, and θ=0 K.

  7. Germ Cell Intercellular Bridges

    Science.gov (United States)

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

    2011-01-01

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

  8. Structural and Numerical Chromosome Changes in Colon Cancer Develop through Telomere-Mediated Anaphase Bridges, Not through Mitotic Multipolarity

    National Research Council Canada - National Science Library

    Ylva Stewénius; Ludmila Gorunova; Tord Jonson; Nina Larsson; Mattias Höglund; Nils Mandahl; Fredrik Mertens; Felix Mitelman; David Gisselsson; Bert Vogelstein

    2005-01-01

    ... have been little explored. We show here that abnormally short telomeres lead to a wide spectrum of mitotic disturbances in colorectal cancer cell lines, including anaphase bridging, whole-chromosome lagging, and mitotic multipolarity...

  9. Pattern matching through Chaos Game Representation: bridging numerical and discrete data structures for biological sequence analysis

    Directory of Open Access Journals (Sweden)

    Vinga Susana

    2012-05-01

    Full Text Available Abstract Background Chaos Game Representation (CGR is an iterated function that bijectively maps discrete sequences into a continuous domain. As a result, discrete sequences can be object of statistical and topological analyses otherwise reserved to numerical systems. Characteristically, CGR coordinates of substrings sharing an L-long suffix will be located within 2-L distance of each other. In the two decades since its original proposal, CGR has been generalized beyond its original focus on genomic sequences and has been successfully applied to a wide range of problems in bioinformatics. This report explores the possibility that it can be further extended to approach algorithms that rely on discrete, graph-based representations. Results The exploratory analysis described here consisted of selecting foundational string problems and refactoring them using CGR-based algorithms. We found that CGR can take the role of suffix trees and emulate sophisticated string algorithms, efficiently solving exact and approximate string matching problems such as finding all palindromes and tandem repeats, and matching with mismatches. The common feature of these problems is that they use longest common extension (LCE queries as subtasks of their procedures, which we show to have a constant time solution with CGR. Additionally, we show that CGR can be used as a rolling hash function within the Rabin-Karp algorithm. Conclusions The analysis of biological sequences relies on algorithmic foundations facing mounting challenges, both logistic (performance and analytical (lack of unifying mathematical framework. CGR is found to provide the latter and to promise the former: graph-based data structures for sequence analysis operations are entailed by numerical-based data structures produced by CGR maps, providing a unifying analytical framework for a diversity of pattern matching problems.

  10. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

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

  11. Zn++ Binding Disrupts the Asp23-Lys28 Salt Bridge without Altering the Hairpin-Shaped Cross-β Structure of Aβ42 Amyloid Aggregates

    Science.gov (United States)

    Mithu, Venus Singh; Sarkar, Bidyut; Bhowmik, Debanjan; Chandrakesan, Muralidharan; Maiti, Sudipta; Madhu, Perunthiruthy K.

    2011-01-01

    Observations like high Zn2+ concentrations in senile plaques found in the brains of Alzheimer's patients and evidences emphasizing the role of Zn2+ in amyloid-β (Aβ)-induced toxicity have triggered wide interest in understanding the nature of Zn2+-Aβ interaction. In vivo and in vitro studies have shown that aggregation kinetics, toxicity, and morphology of Aβ aggregates are perturbed in the presence of Zn2+. Structural studies have revealed that Zn2+ has a binding site in the N-terminal region of monomeric Aβ, but not much is precisely known about the nature of binding of Zn2+ with aggregated forms of Aβ or its effect on the molecular structure of these aggregates. Here, we explore this aspect of the Zn2+-Aβ interaction using one- and two-dimensional 13C and 15N solid-state NMR. We find that Zn2+ causes major structural changes in the N-terminal and the loop region connecting the two β-sheets. It breaks the salt bridge between the side chains of Asp23 and Lys28 by driving these residues into nonsalt-bridge-forming conformations. However, the cross-β structure of Aβ42 aggregates remains unperturbed though the fibrillar morphology changes distinctly. We conclude that the salt bridge is not important for defining the characteristic molecular architecture of Aβ42 but is significant for determining its fibrillar morphology and toxicity. PMID:22261072

  12. Zn(++) binding disrupts the Asp(23)-Lys(28) salt bridge without altering the hairpin-shaped cross-β Structure of Aβ(42) amyloid aggregates.

    Science.gov (United States)

    Mithu, Venus Singh; Sarkar, Bidyut; Bhowmik, Debanjan; Chandrakesan, Muralidharan; Maiti, Sudipta; Madhu, Perunthiruthy K

    2011-12-07

    Observations like high Zn(2+) concentrations in senile plaques found in the brains of Alzheimer's patients and evidences emphasizing the role of Zn(2+) in amyloid-β (Aβ)-induced toxicity have triggered wide interest in understanding the nature of Zn(2+)-Aβ interaction. In vivo and in vitro studies have shown that aggregation kinetics, toxicity, and morphology of Aβ aggregates are perturbed in the presence of Zn(2+). Structural studies have revealed that Zn(2+) has a binding site in the N-terminal region of monomeric Aβ, but not much is precisely known about the nature of binding of Zn(2+) with aggregated forms of Aβ or its effect on the molecular structure of these aggregates. Here, we explore this aspect of the Zn(2+)-Aβ interaction using one- and two-dimensional (13)C and (15)N solid-state NMR. We find that Zn(2+) causes major structural changes in the N-terminal and the loop region connecting the two β-sheets. It breaks the salt bridge between the side chains of Asp(23) and Lys(28) by driving these residues into nonsalt-bridge-forming conformations. However, the cross-β structure of Aβ(42) aggregates remains unperturbed though the fibrillar morphology changes distinctly. We conclude that the salt bridge is not important for defining the characteristic molecular architecture of Aβ(42) but is significant for determining its fibrillar morphology and toxicity. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  13. Electronic Structure of Aqueous Solutions: Bridging the Gap Between Theory and Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Tuan Anh; Govoni, Marco; Seidel, Robert; Bradforth, Stephen E.; Schwegler, Eric; Galli, Giulia

    2017-06-01

    Predicting the electronic properties of aqueous liquids has been a long-standing challenge for quantum mechanical methods. However, it is a crucial step in understanding and predicting the key role played by aqueous solutions and electrolytes in a wide variety of emerging energy and environmental technologies, including battery and photoelectrochemical cell design. We propose an efficient and accurate approach to predict the electronic properties of aqueous solutions, on the basis of the combination of first-principles methods and experimental validation using state-of-the-art spectroscopic measurements. We present results of the photoelectron spectra of a broad range of solvated ions, showing that first-principles molecular dynamics simulations and electronic structure calculations using dielectric hybrid functionals provide a quantitative description of the electronic properties of the solvent and solutes, including excitation energies. The proposed computational framework is general and applicable to other liquids, thereby offering great promise in understanding and engineering solutions and liquid electrolytes for a variety of important energy technologies.

  14. Design, synthesis, insecticidal activity, and structure-activity relationship (SAR): studies of novel triazone derivatives containing a urea bridge group based on transient receptor potential (TRP) channels.

    Science.gov (United States)

    Yang, Yan; Liu, Yuxiu; Song, Hongjian; Li, Yongqiang; Wang, Qingmin

    2016-11-01

    Numerous compounds containing urea bridge and biurea moieties are used in a variety of fields, especially as drugs and pesticides. To search for novel, environmentally benign and ecologically safe pesticides with unique modes of action, four series of novel triazone analogues containing urea, thiourea, biurea, and thiobiurea bridge, respectively, were designed and synthesized, according to various calcium ion channel inhibitors which act on transient receptor potential protein. Their structures were characterized by [Formula: see text] NMR, [Formula: see text] NMR, and HRMS. The insecticidal activities of the new compounds were obtained. The bioassay results indicated that compounds containing a thiourea bridge and a thiobiurea bridge exhibited excellent insecticidal activities against bean aphid. Specifically, compounds [Formula: see text], [Formula: see text], and [Formula: see text] exhibited 85, 90, and 95 % activities, respectively, at 10 mg/kg. Compounds [Formula: see text] (30 %), [Formula: see text] (35 %), [Formula: see text] (30 %), and [Formula: see text] (40 %) exhibited the approximate aphicidal activity of pymetrozine (30 %) at 5 mg/kg. In addition, some target compounds exhibited insecticidal activities against lepidopteran pests. From a molecular design standpoint, the information obtained in this study could help in the further design of new derivatives with improved insecticidal activities.

  15. Transition-sized Au92 nanoparticle bridging non-fcc-structured gold nanoclusters and fcc-structured gold nanocrystals.

    Science.gov (United States)

    Liao, Lingwen; Chen, Jishi; Wang, Chengming; Zhuang, Shengli; Yan, Nan; Yao, Chuanhao; Xia, Nan; Li, Lingling; Bao, Xiaoli; Wu, Zhikun

    2016-10-04

    Herein, we report the intriguing structure, optical absorption and electrochemical properties of the transition-sized Au92(TBBT)44 (Au92 for short, TBBT = 4-tert-butylbenzenethiolate) nanoparticle. An interesting observation is the 4H phase array of Au92 nanoparticles in the unit cells of single crystals.

  16. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

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

    2004-01-01

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

  17. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

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

    2005-01-01

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

  18. Synthesis, Properties and Structure of a Novel Unsymmetrical Bis (phenoxo) Bridged Binuclear Copper (

    Institute of Scientific and Technical Information of China (English)

    LU; Tong-bu

    2001-01-01

    [1]Koga T. , Furutachi H. , Nakamura T. , et al. , Inorg. Chem. , 37, 989(1998)[2]Koolhaas G. J. A. A. , Driessen W.L. , Reedijk J. , et al. , J. Chem. Soc. , Chem. Commun., 5. 517(1995)[3]Collinson S. R. , Fenton D. E. , Coord. Chem. Rev. , 148, 19(1996)[4]Coughlin P. K. , Dewan J. C. , Lippard S. J. , et al. , J. Am. Chem. Soc. , 101, 265(1979)[5]Drew M. G. B., McCann M., Nelson S. M., J. Chem. Soc., Dalton Trans., 9, 1 868(1981),[6]Drew M. G. B. , J. Chem. Soc. , Chem. Commun. , 7, 1 122(1980)[7]Pierre J. -L. , Chautemps P. , Refaif S. , et al. , J. Am. Chem. Soc. , 117, 1 965(1995)[8]Mao Z. W., Chen M. Q., Tan X. S., et al., Inorg. Chem., 34, 2 889(1995)[9]Lu Q. , Luo Q. H., Dai A. B., J. Chem. Soc., Chem. Commun., 4, 1 429(1990)[10]Okawa H. , Nishio J. , Ohba M. , et al. , Inorg. Chem., 32, 2 949(1993)[11]Yonemura M. , Matsumuro Y. , Furutachi H. , et al. , Inorg. Chem. , 36, 2 711(1997)[12]Furutachi H. , Okawa H. , Inorg. Chem. , 36, 3 911(1997)[13]Karunakaran S. , Kandaswamy M. , J. Chem. Soc. , Dalton Trans. , 10, 1 595(1994)[14]Marappan M., Narayanan V. , Kandaswamy M. , J. Chem. Soc. , Dalton Trans. , 20, 3 405(1998)[15]Sheldrick G. M. SHELXTL (Revision 5.03), System of Computer Programs for X-ray Structure Determination,University of Cambridge, 1993[16]Hong S. H., Applications of Spectra Methods in Organic Chemistry[M], Science Press, Beijing, 56(1980)[17]Lu T. B. , Gan X. M. , Tang N. , et al. , Chemical Research in Chinese Universities, 9, 319(1992)[18]Gan X. M. , Liang Z.J., Lu T. B. , et al. , Chemical Research in Chinese Universities, 12(4), 332(1996)[19]Lu T. B. , Li X, Y. , Mao Z. W. , et al. , Polyhedron, 17, 75(1998)[20]Yokoi H. , Sai M. , Isobe T. , et al. , Bull. Chem. Soc. Jpn. , 45, 2 189(1972)[21]Simmons C. J., Lundeen M. , Seff K. , Inorg. Chem. , 17, 1 429(1978)[22]Dehand J. , Jordanow J. , Keck F. , et al. , Inorg. Chem. , 18, 1 543(1979)[23

  19. Structural evaluation of a prestressed concrete bridge under an alkali-silica reaction; Evaluacion estructural de un puente de hormigon pretensado afectado por una reaccion alcali-silice

    Energy Technology Data Exchange (ETDEWEB)

    Carpintero Garcia, I.; Bermudez Adriozola, B.

    2010-07-01

    The Central Laboratory of Structures and Materials (CEDEX) was commissioned by the National Department of Highways to evaluate the safety conditions of one bridge built on 1997, which is part of the net of the Spanish National Highways. Even at the first inspection many cracks were detected in the concrete deck, associated with expansion concrete processes. This examination revealed that concrete deterioration was not associated with any reinforcement corrosion process; in fact, there were no symptoms of this pathology all along the bridge. for that reason the internal chemical reactions were considered as the most probable cause for the expansion of concrete, as no symptoms of deterioration due to external attack were found. In order to check the origin of concrete expansion, some tests were carried out on concrete samples drilled on the decks. Results of these tests show that there had been internal reactions in concrete mass which explains its expansion and the appearance of those cracks observed. Further more, some other activities were also carried out on site to estimate the importance of the structural damages, as topographic levelling and dynamic testing of the decks. Also the mechanical properties of concrete probes were tested at laboratory. This article shows the main results obtained on the study carried on to determine the cause and significance of the structural damages of the bridge. (Author) 3 refs.

  20. Structure and second-order NLO property of the molecules bridged through n-vertex bis-substituted carborane (n=5, 6, 7)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Density functional theory (DFT) B3LYP at 6-31G* level is employed to optimize the structures of the molecules bridged through n-vertex bis-substituted carborane (n=5, 6, 7) and combined with finite field (FF) formalism to calculate the second-order NLO properties. The results indicate that the structures of n-vertex bis-substituted carborane (n=5, 6, 7) are changed due to bridged donor and acceptor moieties. The distances between two C atoms are becoming longer. And the stability and dipole moment are influenced by changing substituted positions of C atoms. The isomers with the substituents connecting with C atoms of lower coordination number have better stability and larger values of polarizability. One-dimensional structure of the molecules bridged through n-vertex bis-substituted carborane (n=5, 6, 7) is in favor of intramolecular charge-transfer. Meanwhile, the isomer with a larger change of dipole moment has larger value of second-order NLO properties during the charge-transfer process.

  1. Formation of native disulfide bonds in endothelin-1. Structural evidence for the involvement of a highly specific salt bridge between the prosequence and the endothelin-1 sequence.

    Science.gov (United States)

    Aumelas, A; Kubo, S; Chino, N; Chiche, L; Forest, E; Roumestand, C; Kobayashi, Y

    1998-04-14

    The [Lys-Arg]-endothelin-1 analogue (KR-ET-1) yields almost selectively the native disulfide pattern (96%), in contrast to endothelin-1 (ET-1) that gives at least 25% of the non-native disulfide pattern. We have previously shown that the carboxylate-state structure of KR-ET-1 is more constrained and stabilized by a salt bridge between Arg(-1) and the Asp8 or Glu10 side chain [Aumelas et al. (1995) Biochemistry 34, 4546-4561]. To identify this salt bridge and its potential involvement in the disulfide bond formation, [E10Q], [D18N], and [D8N] carboxamide analogues were studied, which led to the unambiguous identification of the Arg(-1)-Asp8 salt bridge. Furthermore, while [E10Q] and [D18N] analogues gave a high yield of the native isomer (>/=90%), the [D8N] analogue afforded a ratio of the two isomers close to that observed for ET-1 (68%) [Kubo et al. (1997) Lett. Pept. Sci. 4, 185-192]. Assuming that the formation of disulfide bonds occurs in a thermodynamically controlled step, we have hypothesized that the Arg(-1)-Asp8 salt bridge and concomitant interactions could be responsible for the increase in yield of the native isomer of KR-ET-1. In the present work, we describe the structural studies of the carboxamide analogues and of the minor non-native KR-ET-1 isomer. On the basis of 1H NMR and CD spectra as a function of pH, [E10Q] and [D18N] analogues display a conformational change similar to that of the parent peptide, whereas the structure of the [D8N] analogue is unchanged. For the non-native isomer, we measured a lower helical content than for the native isomer and observed a marked difference in the orientation of the KRCSC backbone. In addition, no salt bridge was experimentally observed. Altogether, these results allow us to hypothesize that the salt bridge between two highly conserved residues, one belonging to the prosequence [Arg(-1)] and the other to the mature sequence [Asp8], is involved in the formation of the native disulfide isomer of ET-1. The

  2. An Expert System for Concrete Bridge Management

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  3. X-ray crystal structure of arsenite-inhibited xanthine oxidase: μ-sulfido,μ-oxo double bridge between molybdenum and arsenic in the active site.

    Science.gov (United States)

    Cao, Hongnan; Hall, James; Hille, Russ

    2011-08-17

    Xanthine oxidoreductase is a molybdenum-containing enzyme that catalyzes the hydroxylation reaction of sp(2)-hybridized carbon centers of a variety of substrates, including purines, aldehydes, and other heterocyclic compounds. The complex of arsenite-inhibited xanthine oxidase has been characterized previously by UV-vis, electron paramagnetic resonance, and X-ray absorption spectroscopy (XAS), and the catalytically essential sulfido ligand of the square-pyrimidal molybdenum center has been suggested to be involved in arsenite binding through either a μ-sulfido,μ-oxo double bridge or a single μ-sulfido bridge. However, this is contrary to the crystallographically observed single μ-oxo bridge between molybdenum and arsenic in the desulfo form of aldehyde oxidoreductase from Desulfovibrio gigas (an enzyme closely related to xanthine oxidase), whose molybdenum center has an oxo ligand replacing the catalytically essential sulfur, as seen in the functional form of xanthine oxidase. Here we use X-ray crystallography to characterize the molybdenum center of arsenite-inhibited xanthine oxidase and solve the structures of the oxidized and reduced inhibition complexes at 1.82 and 2.11 Å resolution, respectively. We observe μ-sulfido,μ-oxo double bridges between molybdenum and arsenic in the active sites of both complexes. Arsenic is four-coordinate with a distorted trigonal-pyramidal geometry in the oxidized complex and three-coordinate with a distorted trigonal-planar geometry in the reduced complex. The doubly bridged binding mode is in agreement with previous XAS data indicating that the catalytically essential sulfur is also essential for the high affinity of reduced xanthine oxidoreductase for arsenite.

  4. Syntheses, structures, and luminescence behavior of terephthalate bridged lead(II) complexes with tetradentate N-donor Schiff bases

    Science.gov (United States)

    Roy, Subhasis; Choubey, Somnath; Bhar, Kishalay; Khan, Sumitava; Mitra, Partha; Ghosh, Barindra Kumar

    2013-11-01

    Three dinuclear compounds of the types [Pb2(L1)2(μ-tp)](ClO4)2 (1) and [Pb2(L2)2(μ-tp)](ClO4/PF6)2 (2/3) [L1 = N,N'-(bis-(pyridin-2-yl)formylidene)-1,2-ethanediamine; L2 = N,N'-(bis-(pyridin-2-yl)benzylidene)-1,2-ethanediamine and tp = terephthalate dianion] have been synthesized using one-pot reactions of 2:2:1:2 M ratio of Pb(OAc)2ṡ3H2O, L1/L2, piperidinium terephthalate (ptp) and appropriate counter anions in MeOH at room temperature. Compounds 1-3 are characterized on the basis of microanalytical, spectroscopic, thermal and other physicochemical results. X-ray structural analyses of 1-3 reveal each six-coordinated lead(II) center with PbN4O2 chromophore to be bound by four N atoms of L1 in 1 and L2 in 2 and 3 and connected through O atoms of a bis(bidentate) tp bridge. The arrangements of L1/L2 ligand and the tp dianion suggest a void around the metal center presumably occupied by a stereoactive lone pair of electrons that reflect a hemidirected coordination around the metal center. The complexes exhibit reasonable thermal stabilities. In solid states, L1, L2, ptp and 1 display intraligand π → π* fluorescence and 1-3 show ligand-to-metal charge transfer at room temperature.

  5. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  6. Rhenium(IV)-copper(II) heterobimetallic complexes with a bridge malonato ligand. Synthesis, crystal structure, and magnetic properties.

    Science.gov (United States)

    Cuevas, Alicia; Chiozzone, Raúl; Kremer, Carlos; Suescun, Leopoldo; Mombrú, Alvaro; Armentano, Donatella; De Munno, Giovanni; Lloret, Francesc; Cano, Juan; Faus, Juan

    2004-11-29

    The Re(IV) complex [ReCl4(mal)]2-, in the form of two slightly different salts, (AsPh4)1.5(HNEt3)0.5[ReCl4(mal)] (1a) and (AsPh4)(HNEt3)[ReCl4(mal)] (1b), and the Re(IV)-Cu(II) bimetallic complexes [ReCl4(mu-mal)Cu(phen)2].CH3CN (2), [ReCl4(mu-mal)Cu(bpy)2] (3), and [ReCl4(mu-mal)Cu(terpy)] (4) (mal=malonate dianion, AsPh4=tetraphenylarsonium cation, HNEt3=triethylammonium cation, phen=1,10-phenanthroline, bpy=2,2'-bipyridine and terpy=2,2':6',2' '-terpyridine) have been synthesized and the structures of 1a, 1b, 2, and 3 determined by single-crystal X-ray diffraction. The structures of 1a and 1b are made up of discrete [ReCl4(mal)]2- anions and AsPh4+ and HNEt3+ cations, held together by electrostatic forces and hydrogen bonds. The Re(IV) atom is surrounded by four chloride anions and a bidentate malonate group, in a distorted octahedral environment. The structure of 2 consist of neutral dinuclear units [ReCl4(mu-mal)Cu(phen)2], with the metal ions united through a bridge carboxilato. The environment of Re(IV) is nearly identical to that in the mononuclear complex, and Cu(II) is five coordinate, being surrounded by four nitrogen atoms of two bidentate phen ligands and one oxygen atom of the malonato ligand. In 3, there are also dinuclear units, [ReCl4(mu-mal)Cu(bpy)2], but the Cu(II) ions complete a distorted octahedral coordination by binding with the free malonato oxygen atom of a neighbor unit, resulting in an infinite chain. The magnetic properties of 1-4 were also investigated in the temperature range 2.0-300 K. The magnetic behavior of 1a and 1b is as expected for a Re(IV) complex with a large value of the zero-field splitting (2D ca. 110 cm(-1)). For the bimetallic complexes, the magnetic coupling between Re(IV) and Cu(II) is antiferromagnetic in 2 (J=-0.39 cm(-1)), ferromagnetic in 4 (J=+1.51 cm(-1)), and nearly negligible in 3 (J=-0.09 cm(-1)).

  7. Bridge over troubled water?

    DEFF Research Database (Denmark)

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

    2008-01-01

    The problem of integrating non-Western immigrants into Western welfare states is the focus of this paper. To address this issue, we suggest a social capital approach in which we apply the conceptual pair of bridging social capital (BR), which connects an individual to the broader social structure...

  8. Istanbul Bridge Conference 2014

    CERN Document Server

    Gülkan, Polat; Mahmoud, Khaled

    2016-01-01

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

  9. Building Bridges One Line at a Time

    Science.gov (United States)

    Grigsby, Cathy Murray

    2012-01-01

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

  10. Structural Behavior of a Long-Span Partially Earth-Anchored Cable-Stayed Bridge during Installation of a Key Segment by Thermal Prestressing

    Directory of Open Access Journals (Sweden)

    Sang-Hyo Kim

    2016-08-01

    Full Text Available This study investigated structural behavior of long-span partially earth-anchored cable-stayed bridges with a main span length of 810 m that use a new key segment closing method based on a thermal prestressing technique. A detailed construction sequence analysis matched with the free cantilever method (FCM was performed using a three-dimensional finite element (FE model of a partially earth-anchored cable-stayed bridge. The new method offers an effective way of connecting key segments by avoiding large movements resulting from the removal of the longitudinal restraint owing to the asymmetry of axial forces in the girders near the pylons. The new method develops new member forces through the process of heating the cantilever system before installing the key segment and cooling the system continuously after installing key segments. The resulting forces developed by the thermal process enhance the structural behavior of partially earth-anchored cable-stayed bridges owing to decreased axial forces in the girders.

  11. Synthesis, structural studies, and oxidation catalysis of the late-first-row-transition-metal complexes of a 2-pyridylmethyl pendant-armed ethylene cross-bridged cyclam.

    Science.gov (United States)

    Jones, Donald G; Wilson, Kevin R; Cannon-Smith, Desiray J; Shircliff, Anthony D; Zhang, Zhan; Chen, Zhuqi; Prior, Timothy J; Yin, Guochuan; Hubin, Timothy J

    2015-03-02

    The first 2-pyridylmethyl pendant-armed ethylene cross-bridged cyclam ligand has been synthesized and successfully complexed to Mn(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), and Zn(2+) cations. X-ray crystal structures were obtained for all six complexes and demonstrate pentadentate binding of the ligand with the requisite cis-V configuration of the cross-bridged cyclam ring in all cases, leaving a potential labile binding site cis to the pyridine donor for interaction of the complex with oxidants and/or substrates. The electronic properties of the complexes were evaluated using solid-state magnetic moment determination and acetonitrile solution electronic spectroscopy, which both agree with the crystal structure determination of high-spin divalent metal complexes in all cases. Cyclic voltammetry in acetonitrile revealed reversible redox processes in all but the Ni(2+) complex, suggesting that catalytic reactivity involving electron-transfer processes is possible for complexes of this ligand. Kinetic studies of the dissociation of the ligand from the copper(II) complex under strongly acidic conditions and elevated temperatures revealed that the pyridine pendant arm actually destabilizes the complex compared to the parent cross-bridged cyclam complex. Screening for oxidation catalysis using hydrogen peroxide as the terminal oxidant for the most biologically relevant Mn(2+), Fe(2+), and Cu(2+) complexes identified the Mn(2+) complex as a potential mild oxidation catalyst worthy of continued development.

  12. Synthesis and Crystal Structure of a Three-dimensional Mn(Ⅱ) Coordination Polymer with 3-(Pyrazin-2-yloxy)-pyridine and Azide Anion as Mixed Bridge Ligand

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A three-dimensional coordination polymer [Mn2((1,3-N3)4(μ-PP)2]n (PP = 3-(pyra- zin-2-yloxy)-pyridine) has been synthesized with 3-(pyrazin-2-yloxy)-pyridine and azide anion as mixed bridge ligand, and its crystal structure was determined by X-ray crystallography. The crystal data: triclinic system, space group P, with a = 6.794(4), b = 9.885(6), c = 9.947(6)A, α = 64.170(6),β = 84.190(8),γ = 85.319(8)°, V = 597.7(6)(A)3, Z = 1, C18H14Mn2N18O2, Mr = 624.35, Dc = 1.735 g/cm3, F(000) = 314 andμ= 1.117 mm-1. In the crystal, the azide anion acts as a bridge ligand and makes adjacent Mn(Ⅱ) ions connect into a two-dimensional sheet on the ab plane, then 3-(pyrazin-2-yloxy)-pyridine serves as a bidentate bridge ligand to connect neighboring sheets along the c axis, and finally a three-dimensional structure is formed.

  13. PT L 3 near edge structure of halogen-bridged mixed-valence pt complexes and pd-pt mixed-metal complexes

    Science.gov (United States)

    Tanino, H.; Oyanagi, H.; Yamashita, M.; Kobayashi, K.

    1985-03-01

    X-ray absorption near edge structure (XANES) of halogen-bridged mixed-valence Pt complexes and halogen-bridged Pd-Pt mixed-metal complexes have been measured using synchrotron radiation with a high energy resolution. In Pd-Pt mixed metal complexes, we demonstrate that the degree of the valence is estimated from the intensity of the white line at the Pt L 3 edge. In the mixed-valence complexes, the electron system is proved to be the Peierls insulator with a charge density wave of renormalized d electrons of Pt, where the total valence of Pt IV- and Pt 11 is conserved without excess electrons from ligands or anions.

  14. Theoretical study on magneto-structural correlation of trinuclear copper (II) complex with the hydroxo bridge and bidentate syn-syn carboxylate group

    Institute of Scientific and Technical Information of China (English)

    QI Zhongnan; WU Jian; LIU Chengbu; WANG Ruoxi; SUN Youmin

    2006-01-01

    The theoretical study on magneto- structural correlation in linear trinuclear Cu (II) complex bridged by hydroxo group and bidentate formato group has been performed using the broken symmetry approach with the framework of density functional theory (DFT-BS). The magnetic coupling constant for the model complex is 70.97 cm-1, comparable with the experimentally measured J value (77 cm-1). The calculated results show that the magnetic coupling interaction firstly slightly increases with the changes of the coordination environment around the terminal Cu atoms from a distorted square pyramid to a trigonal bi-pyramid, and decreases subsequently. In the course of changes, the sign of J value shifts from positive to negative. The magnetic coupling interaction is sensitive to coordination environment of the terminal Cu. The calculated results also reveal that the ferromagnetic coupling arises from the countercomplementarity of the hydroxo and formato bridges. Molecular orbital analysis validates the conclusion.

  15. Bridged graphite oxide materials

    Science.gov (United States)

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

    2010-01-01

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

  16. Structure of a Berberine Bridge Enzyme-Like Enzyme with an Active Site Specific to the Plant Family Brassicaceae

    DEFF Research Database (Denmark)

    Daniel, Bastian; Wallner, Silvia; Steiner, Barbara;

    2016-01-01

    Berberine bridge enzyme-like (BBE-like) proteins form a multigene family (pfam 08031), which is present in plants, fungi and bacteria. They adopt the vanillyl alcohol-oxidase fold and predominantly show bi-covalent tethering of the FAD cofactor to a cysteine and histidine residue, respectively...

  17. Synthesis, crystal structure and magnetic properties of terephthalate-isophthalete- and phthalate-bridged copper (II) dinuclear complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cano, J.; De Munno, G.; Sanz, J.L.; Ruiz, R.; Lloret, F.; Faus, J.; Julve, M.

    1997-09-01

    The ability of the dianions of the terephthalic (H{sub 2}ta), isophthalic (H{sub 2} ita) and phthalic (H{sub 2} phta) acids both to act as bridges between copper (II) ions and to mediate intramolecular exchange interactions has been investigated by single crystal X-ray diffraction and variable-temperature magnetic susceptibility measurements. (Author) 31 refs.

  18. Synthesis, crystal structure and magnetic properties of an oxalato-bridged Re(IV)Mo(VI) heterobimetallic complex.

    Science.gov (United States)

    Martínez-Lillo, José; Armentano, Donatella; De Munno, Giovanni; Lloret, Francesc; Julve, Miguel; Faus, Juan

    2011-05-14

    The Re(IV)-Mo(VI) compound of formula (PPh(4))(2)[ReCl(4)(μ-ox)MoO(2)Cl(2)] (1) constitutes the first example of a heterodinuclear oxalato-bridged complex in the coordination chemistry of molybdenum.

  19. Vibrational analysis of amino acids and short peptides in aqueous media. V. The effect of the disulfide bridge on the structural features of the peptide hormone somatostatin-14.

    Science.gov (United States)

    Hernández, Belén; Carelli, Claude; Coïc, Yves-Marie; De Coninck, Joël; Ghomi, Mahmoud

    2009-09-24

    To emphasize the role played by the S-S bridge in the structural features of somatostatin-14 (SST-14), newly recorded CD and Raman spectra of this cyclic peptide and its open analogue obtained by Cys-->Ser substitution are presented. CD spectra of both peptides recorded in aqueous solutions in the 100-500 microM concentration range are strikingly similar. They reveal principally that random conformers constitute the major population in both peptides. Consequently, the S-S bridge has no structuring effect at submillimolar concentrations. In methanol, the CD spectrum of somatostatin-14 keeps globally the same spectral shape as that observed in water, whereas its open analogue presents a major population of helical conformers. Raman spectra recorded as a function of peptide concentration (5-20 mM) and also in the presence of 150 mM NaCl provide valuable conformational information. All Raman spectra present a mixture of random and beta-hairpin structures for both cyclic and open peptides. More importantly, the presence or the absence of the disulfide bridge does not seem to influence considerably different populations of secondary structures within this range of concentrations. CD and Raman data obtained in the submillimolar and millimolar ranges of concentrations, respectively, lead us to accept the idea that SST-14 monomers aggregate upon increasing concentration, thus stabilizing beta-hairpin conformations in solution. However, even at high concentrations, random conformers do not disappear. Raman spectra of SST-14 also reveal a concentration effect on the flexibility of the S-S linkage and consequently on that of its cyclic part. In conclusion, although the disulfide linkage does not seem to markedly influence the SST-14 conformational features in aqueous solutions, its presence seems to be necessary to ensure the flexibility of the cyclic part of this peptide and to maintain its closed structure in lower dielectric constant environments.

  20. Density functional study for the bridged dinuclear center based on a high-resolution X-ray crystal structure of ba3 cytochrome c oxidase from Thermus thermophilus.

    Science.gov (United States)

    Du, Wen-Ge Han; Noodleman, Louis

    2013-12-16

    Strong electron density for a peroxide type dioxygen species bridging the Fea3 and CuB dinuclear center (DNC) was observed in the high-resolution (1.8 Å) X-ray crystal structures (PDB entries 3S8G and 3S8F) of ba3 cytochrome c oxidase (CcO) from Thermus thermophilus. The crystals represent the as-isolated X-ray photoreduced CcO structures. The bridging peroxide was proposed to arise from the recombination of two radiation-produced HO(•) radicals formed either very near to or even in the space between the two metals of the DNC. It is unclear whether this peroxide species is in the O2(2-), O2(•)(-), HO2(-), or the H2O2 form and what is the detailed electronic structure and binding geometry including the DNC. In order to answer what form of this dioxygen species was observed in the DNC of the 1.8 Å X-ray CcO crystal structure (3S8G), we have applied broken-symmetry density functional theory (BS-DFT) geometric and energetic calculations (using OLYP potential) on large DNC cluster models with different Fea3-CuB oxidation and spin states and with O2(2-), O2(•)(-), HO2(-), or H2O2 in the bridging position. By comparing the DFT optimized geometries with the X-ray crystal structure (3S8G), we propose that the bridging peroxide is HO2(-). The X-ray crystal structure is likely to represent the superposition of the Fea3(2+)-(HO2(-))-CuB(+) DNC's in different states (Fe(2+) in low spin (LS), intermediate spin (IS), or high spin (HS)) with the majority species having the proton of the HO2(-) residing on the oxygen atom (O1) which is closer to the Fea3(2+) site in the Fea3(2+)-(HO-O)(-)-CuB(+) conformation. Our calculations show that the side chain of Tyr237 is likely trapped in the deprotonated Tyr237(-) anion form in the 3S8G X-ray crystal structure.

  1. Synthesis, Structure and Luminescent Properties of Polymeric Copper(Ⅰ) Halide Complexes Bearing Phosphine and N-donor Bridging Ligands

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Three polymeric copper(Ⅰ) halide complexes bearing phosphine and N-donor bridging ligands, [(PPh3)2Cu2(μ-Br)2(μ-4,4'-bipy)]∞ 1 (bipy=bipyridine), [(PPh3)2Cu2(μ-Br)2(μ-bpe)]∞ 2 (bpe=trans-1,2-bis(4-pyridyl)ethene) and [(PPh3)2Cu2(μ-Cl)2(μ-bpe)]∞ 3, were synthesized by the multilayer diffusion method, and the structures were refined by single-crystal X-ray diffraction. Complex 1 crystallizes in triclinic, space group P-1 with a=9.122(3), b=9.322(3), c=13.201(4) (A),α=106.440(4), β=105.965(5), γ=94.167(5)°, V=1021.3(6) (A), Mr=967.62, Z=1,Dc=1.573 g/cm3, F(000)=486,μ=3.111 mm-1, the final R=0.0383 and wR=0.0960 for 2792observed reflections (I > 2σ(Ⅰ)). Complex 2 crystallizes in triclinic, space group P-1 with a=9.420(3), b=10.209(4), c=12.407(4)(A), α=104.136(6), β=108.132(5), γ=95.338(6)°, V=1081.0(7)(A), Mr=496.83, Z=2, Dc=1.526 g/cm3, F(000)=500,μ=2.941 mm-1, the final R=0.0445 and wR=0.1117 for 3251 observed reflections (I> 2σ(Ⅰ)). Complex 3 crystallizes in triclinic,space group P-1 with a=8.32(1), b=11.53(2), c=13.94(3)(A), α=109.57(3), β=93.85(3), γ=97.28(3)°, V=1242(4)(A)3, Mr=1074.59, Z=1, Dc=1.436 g/cm3, F(000)=548,μ=1.279 mm-1,the final R=0.0786 and wR=0.1586 for 2266 observed reflections (I > 2σ(Ⅰ)). The complexes exhibit intensive solid-state photoluminescence tentatively assigned to an admixture of triplet intraligand (IL) and metal-to-ligand charge-transfer (MLCT) excited state.

  2. Bridging the Gap Between Understanding and Doing in Structural Geology - Coring the Subsurface with Scratch-Art

    Science.gov (United States)

    Bilsley, N. A.; Cook, H. M.

    2016-12-01

    Although most geology students feel the joy of interpreting geologic cross sections, few experience the challenges career geologists face in order to create these visual representations. Without a hefty budget and a drill rig, students generally miss out on the challenge of extrapolating subsurficial features from limited datasets, and jump to narrating geologic time through beautifully pre-drawn cross sections. Although this method allows students to practice relative dating techniques, they miss the practical step of learning how we have come to understand what the subsurface looks like in the first place. This activity was designed to close that gap, while giving students the opportunity to engage in peer learning by strategizing in groups, critiquing each other's work, and evaluating their own work. Broken into groups, students are instructed to create a geologic cross section that must include specific structural features. The cross sections are traded with another group, who reviews and provides feedback on the drawing before returning it back to the original group. The feedback is reviewed and incorporated, before the cross sections are colored and covered with black coated, clear scratch-art paper. The hidden cross sections are traded with a new group, who must decide where and how deep to scratch, or "core", on their cross section. Utilizing the data obtained from the cores, the students interpret and draw a new cross section. Finally, the scratch-art paper is removed, and the original cross section revealed. The differences between the original and interpreted subsurface as well as evaluation of sampling methods (e.g. location and depth of cores) are discussed within the groups and with the class. This activity bridges the gap between developing the intuition needed to create cross sections with realistic geoscientific techniques and utilizing cross sections to understand geologic time. In addition, not only does the activity require few supplies and

  3. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...... Belgrade), Leo Pekkala (Finnish Centre for Media Education and Audiovisual Media/MEKU), Julie Uldam (Network on Civic Engagement and Social Innovation) and Gabriella Velics (Community Media Forum Europe)....

  4. Bond cleavage reactions of the bridge structure in coal in the presence of hydrogen donating compounds; Suiso kyoyosei kagobutsu sonzaika deno sekitanchu no kakyo kozo no kairetsu hanno

    Energy Technology Data Exchange (ETDEWEB)

    Bando, N.; Kidena, K.; Murata, S.; Nomura, M. [Osaka University, Osaka (Japan). Faculty of Engineering

    1996-10-28

    In this paper, bond cleavage reactions are discussed in relation to the softening and solubilization of coal. Were used 9,10-dihydroanthracene (DHA) and 9,10-dihydrophenanthrene (DHP) as models of hydrogen donating compounds in coal, and bibenzyl, 1,2-diethane, benzylphenylether, and 1,5-dibenzylnaphthalene were used as models of bridge structure compounds. They were compared mutually, as to reactivity of coal against DHA and DHP. For the homolytic cleavage of bridges, DHA with excellent radical supplement performance provided excellent hydrogen donating performance. While, for the ipso-position cleavage of bridges, it was found that DHP can act as an effective hydrogen donor. For the reaction between coal and hydrogenated aromatic compounds, cleavage of relatively weak bonds, such as ether linkage and dimethylene linkage, occurred at about 380{degree}C, and hydrogen from DHA or DHP was consumed. On the other hand, the results suggested that the cleavage reaction at ipso-position affected by hydrogen donating solvent is also important at temperature range around 420{degree}C. 2 refs., 3 figs., 1 tab.

  5. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex: [NdFe(CN)6(DMF)4(H2O)3]·H2O

    Institute of Scientific and Technical Information of China (English)

    李建荣; 郭国聪; 王明盛; 周国伟; 卜显和; 黄锦顺

    2003-01-01

    A new bimetallic cyano-bridged complex, [NdFe(CN)6(DMF)4(H2O)3]@H2O (DMF= N,N-dimethylformamide) 1, has been obtained by the reaction of hexacyanoferrate potassium with neodymium (Ⅲ) chloride in H2O/EtOH/DMF (volume ratio: 2:2:1), and its structure was determined by means of single-crystal X-ray diffraction. The compound crystallizes in space group P21/n of monoclinic system with cell parameters: a = 17.646(1), b = 8.9011(3), c = 19.945(1) A, β = 95.835(2)°, V= 3116.6(3) A3, Z = 4, Dc = 1.536 g/cm3, Mr = 720.66, F(000) = 1456, μ = 2.166 mm-1, R = 0.0386, wR = 0.1120 and S = 1.061. The central Nd (Ⅲ) ion is coordinated by seven oxygen atoms of four DMF molecules and three water molecules and one nitrogen atom of the bridging cyanide in a slightly distorted square-antiprism arrangement, and the Fe (Ⅲ) ion is in an almost octahedral environment coordinated to six cyano-ligands, of which one cyanide ligand bridges the Nd (Ⅲ) ion to form a bimetallic complex. Molecules of complexes in the crystal lattice are held together by hydrogen bonding, forming a three-dimensional framework.

  6. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  7. Bridge Engineering-Oriented Parametric Model

    Institute of Scientific and Technical Information of China (English)

    周凌远; 李乔

    2004-01-01

    A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a software system. This model provides both convenience and flexibility for users in structural modeling process. The object-oriented method is applied in the model implementation. A bridge analysis preprocessor is developed on the basis of this model. It provides an effective way for bridge modeling.

  8. Design Optimization and Structural Performance Evaluation of Plate Girder Bridge Constructed Using a Turn-Over Process

    Directory of Open Access Journals (Sweden)

    Gi-Ha Eom

    2017-03-01

    Full Text Available A recent trend in bridge construction has been the optimization of the cost-to-performance ratio. The most effective way to optimize the cost-to-performance ratio is to maximize the efficiency of the superstructure. Currently, many bridge engineers and designers favor two- or three- girder plate superstructures, due to their cost advantages. However, research on the performance enhancements of the I-type girder in two- or three- girder plate bridges is lacking. One of the most important performance improvement technologies for the I-type girder is the “preflex” method. In the preflex method, the specimen is inverted during the construction process to apply prestressed cambering to the specimen by using self-weight. However, a problem with the preflex construction method is difficulty with inverting the girder/plate system during the concrete curing process. Therefore, a new inverting system called Turn-Over (TO wheel was proposed. Using TO wheels, wider variations to the I-type girder design can be achieved. Using this TO construction method, various cross sectional designs of girder plate systems can be considered due to its easiness in inverting the girder/plate system. In this study, the location of concrete confinement sections between the steel I-beams and concrete plates was varied in an I-girder cross-sectional design. Design parameters included effective height, flange thickness, flange width, confining concrete section width, etc. From this study, the optimum cross-sectional design of the I-girder/concrete plate system was achieved. Then, a single 20 m TO girder/plate system and two 20 m TO girder bridges were constructed and tested to evaluate their performance. From the test, failure behavior, load carrying capacity, crack pattern, etc., are obtained. The results are discussed in detail in this paper.

  9. Structure of 15-Level Sub-Module Cascaded H-Bridge Inverter for Speed Control of AC Drive Applications

    Directory of Open Access Journals (Sweden)

    R. Uthirasamy

    2015-02-01

    Full Text Available This paper deals with the implementation of a single phase 15-level Sub-Multilevel Cascaded H-Bridge Inverter (SMCHBI for variable speed industrial drive applications. It consists of sub-multilevel modules and H-bridge inverter configuration. Sub-multilevel switches synthesize stepped DC link voltage and current from the DC sources. H-bridge inverter switches renovate stepped DC link voltage and current into sinusoidal waveform. Compared with conventional Cascaded Multilevel Inverter (CMLI, the proposed system employs the reduced number of power switches, DC sources and gate driver requirements. The proposed system not only reduces the overall system cost but also reduces the voltage stress across the inverter switches. The proposed system does not required additional resonant soft switching circuits for Zero Voltage Switching (ZVS of inverter. In the proposed method, variable frequency method is adopted for the speed control of industrial induction motor drives. A prototype model of 15-level SMCHB is developed and the performance of the systems is validated experimentally.

  10. Torsional instability in suspension bridges: The Tacoma Narrows Bridge case

    Science.gov (United States)

    Arioli, Gianni; Gazzola, Filippo

    2017-01-01

    All attempts of aeroelastic explanations for the torsional instability of suspension bridges have been somehow criticised and none of them is unanimously accepted by the scientific community. We suggest a new nonlinear model for a suspension bridge and we perform numerical experiments with the parameters corresponding to the collapsed Tacoma Narrows Bridge. We show that the thresholds of instability are in line with those observed the day of the collapse. Our analysis enables us to give a new explanation for the torsional instability, only based on the nonlinear behavior of the structure.

  11. Synthesis,structure,and magnetic properties of a cyanide-bridged Fe(Ⅲ)-Cu(Ⅱ)bimetallic double-zigzag chain with slow relaxation of the magnetization

    Institute of Scientific and Technical Information of China (English)

    DONG DaPeng; ZHENG Hui; ZHAO Liang; ZHUANG PengFei; LIU Tao; HE Cheng; DUAN ChunYing

    2012-01-01

    Using BuaN[Fe(Tp*)(CN)3]-(Tp* =hydrotris(3,5-dimethylpyrazol-l-yl)borate)as the building block to react with CuⅡ and N-methylimidazole,we obtained a one-dimensional(1D)heterobimetallic cyano-bridged chain,[Fe(Tp*)(CN)3]2Cu(N- methylimidazole)2·2H2O(1).The crystal structures and magnetic studies demonstrate that complex 1 exhibits slow relaxation of the magnetization due to strong intrachain ferromagnetic coupling and weak interchain interactions.

  12. 23 CFR 650.809 - Movable span bridges.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Movable span bridges. 650.809 Section 650.809 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Navigational Clearances for Bridges § 650.809 Movable span bridges. A fixed...

  13. 23 CFR 650.705 - Application for discretionary bridge funds.

    Science.gov (United States)

    2010-04-01

    ... TRAFFIC OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Discretionary Bridge Candidate Rating Factor § 650... cost, current average daily truck traffic and a narrative describing the existing bridge, the proposed new or rehabilitated bridge and other relevant factors which the State believes may warrant...

  14. Structural criteria for the rational design of selective ligands. 2. Effect of alkyl substitution on metal ion complex stability with ligands bearing ethylene-bridged ether donors

    Energy Technology Data Exchange (ETDEWEB)

    Hay, B.P.; Zhang, D.; Rustad, J.R. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-24

    A novel approach is presented for the application and interpretation of molecular methanics calculations in ligand structural design. The methodology yields strain energies that (i) provide a yardstick for the measurements of ligand binding site organization for metal ion complexation and (ii) allow the comparison of any two ligands independent of either the number and type of donor atoms or the identity of the metal ion. Application of this methodology is demonstrated in a detailed examination of the influence of alkyl substitution on the structural organization of ethylene-bridged, bidentate, ether donor ligands for the alkali and alkaline earth cations. Nine cases are examined, including the unsubstituted ethylene bridge (dimethoxyethane), all possible arrangements of individual alkyl groups (monoalkylation, gem-dialkylation, meso-dialkylation, d,l-dialkylation, trialkylation, and tetraalkylation), and both cis and trans attachments of the cyclohexyl group. The calculated degree of binding site organization for metal ion complexation afforded by these connecting structures is shown to correlate with known changes in complex stability caused by alkyl substitution of crown ether macrocycles.

  15. Syntheses and Crystal Structures of Two Two-dimensional Coordination Polymers with 2,3-Dimethylpyrazine-1,4-dioxide and Thiocyanate as Mixed Bridge Ligands

    Institute of Scientific and Technical Information of China (English)

    SHI Jing-Min; LI Wei-Nan; ZHANG Feng-Xia; ZHANG Xia; LIU Lian-Dong

    2007-01-01

    Two two-dimensional coordination polymers,[Cd(μ1,3-SCN-)2(μ1,6-L)]n 1 and [Co(μ1,3-SCN-)2(μ1,6-L)]n 2,have been synthesized with 2,3-dimethylpyrazine-1,4-dioxide (L) and thiocyanate as mixed bridging ligands,and their crystal structures were determined by X-ray crystallography.Both crystals belong to monoclinic system,space group C2/c.The other crystal parameters are as follows:for complex 1:a = 9.732(3),b = 14.658(5),c = 8.811(3) (A),β =102.935(4)°,Z = 4,V = 1225.1(7)(A)3,CsHsCdN4O2S2,Mr = 368.71,Dc.-- 1.999 g/cm3,F(000) =720 andμ = 2.117 mm-1;for complex 2:a = 9.528(7),b = 14.563(11),c = 8.415(6) (A),β =102.195(9)°,V= 1141.3(14) (A)3,Z = 4,C8H8CoN4O2S2,Mr = 315.23,Dc = 1.835 g/cm3,F(000) =636 andμ = 1.863 mm-1.The two complexes show similar two-dimensional sheet structures.Along the c axis one-dimensional chains are constructed by the coordination of Cd(Ⅱ) (or Co(Ⅱ))ions with μ1,6-L bridging ligand,and the μ1,3-SCN- bridging ligands make the chains connect to each other,resulting in the formation of a two-dimensional sheet on the ac plane.

  16. Chiral cyanide-bridged 1D FeⅢ-MnⅢ heterobimetallic chains: Synthesis,structures and magnetic properties%Chiral cyanide-bridged 1D FeⅢ-MnⅢ heterobimetallic chains:Synthesis,structures and magnetic properties

    Institute of Scientific and Technical Information of China (English)

    YAO MinXia; ZHENG Qi; GAO Feng; LI YiZhi; ZUO JingLin

    2012-01-01

    Two couples of enantiomerically pure chiral cyano-bridged heterobimetallic one-dimensional(1D)chain complexes:[Mn((R,R)-Salphen)Fe(Tp)(CN)3]n(1)and[Mn((S,S)-Salphen)Te(Tp)(CN)3]n(2)(Salphen =N,N1-I,2-diphenyl ethylenebis(salicylideneiminato)dianion,Tp =tris(pyrazolyl)hydroborate),[Mn((R,R)-Salphen)Fe(Tp*)(CN)3·2H2O]n(3)and[Mn((S,S)-Salphen)Fe(Tp*)(CN)3.2H2O]n(4)(Tp* =hydridotris(3,5-dimethylpyrazol- l-yl)borate),have been successfully synthesized by the reactions of MnⅢ schiff-base complexes with the tricyanometalate building block,[(LTp)Fe(CN)3]-(LTp =Tp or Tp*).All complexes are made up of neutral cyano-bridged zigzag double chains with(-Fe-C≡ N-Mn-N≡C-)n as the repeating unit.Circular dichroism(CD)spectra confirm the enantiomeric nature of the optically active complexes.Magnetic studies demonstrate that ferromagnetic interactions are operative in these complexes.The ferromagnetic couplings become weak in the chains with the bending of the Mn-N ≡C angles.

  17. Preparation of Core-Shell Coordination Molecular Assemblies via the Enrichment of Structure-Directing "Codes" of Bridging Ligands and Metathesis of Metal Units

    Energy Technology Data Exchange (ETDEWEB)

    Park, J; Chen, YP; Perry, Z; Li, JR; Zhou, HC

    2014-12-03

    A series of molybdenum- and copper-based MOPs were synthesized through coordination-driven process of a bridging ligand (3,3'-PDBAD, L-1) and dimetal paddlewheel clusters. Three conformers of the ligand exist with an ideal bridging angle between the two carboxylate groups of 0 degrees (H-2 zeta-L(1)), 120 degrees (H-2 beta-L-1), and of 90 degrees (H-2 beta-L-1), respectively. At ambient or lower temperature, (HL1)-L-2 and Mo-2(OAc)(4) or Cu-2(OAc)(4) were crystallized into a molecular square with ?-L-1 and Mo-2/Cu-2 units. With proper temperature elevation, not only the molecular square with ?-L-1 but also a lantern-shaped cage with a-L-1 formed simultaneously. Similar to how Watson-Crick pairs stabilize the helical structure of duplex DNA, the core-shell molecular assembly possesses favorable H-bonding interaction sites. This is dictated by the ligand conformation in the shell, coding for the formation and providing stabilization of the central lantern shaped core, which was not observed without this complementary interaction. On the basis of the crystallographic implications, a heterobimetallic cage was obtained through a postsynthetic metal ion metathesis, showing different reactivity of coordination bonds in the core and shell. As an innovative synthetic strategy, the site-selective metathesis broadens the structural diversity and properties of coordination assemblies.

  18. Magnetic exchange interaction via HF 2--bridges? Structure and magnetism of pipzH 2[MnF 4(HF 2)

    Science.gov (United States)

    Bentrup, U.; Harms, K.; Massa, W.; Pebler, J.

    2000-05-01

    pipzH 2[MnF 4(HF 2)] (pipz=piperazine) has been prepared from an aqueous hydrofluoric acid solution of Mn(III) acetate and its crystal structure was determined by single-crystal X-ray analysis: triclinic, space group Poverline11¯, Z=1, a=5.636(1), b=6.151(1), c=6.498(1) Å, α=99.52(1), β=90.62(1), γ=107.43(1)°, wR2=0.063, R=0.023. The structure consists of hitherto unique anionic chains where [MnF 4] units are bridged by HF 2- anions. The resulting [MnF 6] octahedra are strongly elongated, mainly due to the Jahn-Teller effect ( 1.84 Å, MnF ax 2.19 Å). The geometry of the centrosymmetrical bifluoride anion is close to that of KHF 2 (HF 1.14 Å), the angles at the angular bridge MnFH are 111.7°. Surprisingly, magnetic investigations revealed pure paramagnetic behavior. Thus, in contrast to several examples where antiferromagnetic coupling was observed via OH⋯F hydrogen bonds, the very strong hydrogen bonds in the symmetric F⋯H⋯F - anion are obviously not able to mediate magnetic exchange interactions.

  19. 跨多股道钢箱梁天桥的结构设计%The Structural Design of Steel Box Girder Pedestrian Bridge Crossing Multiple Railways

    Institute of Scientific and Technical Information of China (English)

    沈耀海

    2011-01-01

    结合西部某新建火车站进站人行天桥工程实例,分析了设计和施工的多种控制条件,论证了主梁采用钢箱梁结构的合理性.通过有限元分析和动力特性计算可知,结构设计的控制因素为竖向自振频率,采用中墩与主梁固结的连接方式可以有效地调整结构竖向自振频率.%Based on the project case of one pedestrian bridge in one new constructed railway station at west China, many controlled conditions are analyzed about structural design and engineering construction, and the rationalitles of steel box girder bridge adopted in the design are also demonstrated. It is learned from finite - element analysis and dynamic characteristics calculation that the control factor of structural design is vertical vibration frequency, which can be improved effectively by means of fixed connection between central pier and steel box girder.

  20. Synthesis, molecular structure, computational study and in vitro anticancer activity of dinuclear thiolato-bridged pentamethylcyclopentadienyl Rh(III) and Ir(III) complexes.

    Science.gov (United States)

    Gupta, Gajendra; Garci, Amine; Murray, Benjamin S; Dyson, Paul J; Fabre, Gabin; Trouillas, Patrick; Giannini, Federico; Furrer, Julien; Süss-Fink, Georg; Therrien, Bruno

    2013-11-21

    Neutral dinuclear dithiolato-bridged pentamethylcyclopentadienyl Rh(III) complexes of the type (C5Me5)2Rh2(μ-SR)2Cl2 (R = CH2Ph, 1; R = CH2CH2Ph, 2) and cationic dinuclear trithiolato-bridged pentamethylcyclopentadienyl Rh(III) and Ir(III) complexes of the type [(C5Me5)2M2(μ-SR)3](+) (M = Rh, R = CH2Ph, 3; M = Rh, R = CH2CH2Ph, 5; M = Rh, R = CH2C6H4-p-(t)Bu, 7: M = Ir, R = CH2Ph, 4; M = Ir, R = CH2CH2Ph, 6; M = Ir, R = CH2C6H4-p-(t)Bu, 8) have been synthesized from the chloro-bridged pentamethylcyclopentadienyl Rh(III) and Ir(III) dimers (C5Me5)2M2(μ-Cl)2Cl2 by reaction with the corresponding thiol derivative (RSH). Complexes 3-8 were isolated as chloride salts. All complexes were obtained in good yield and were fully characterized by spectroscopic methods. The molecular structures of the neutral complexes (1 and 2) show interesting features: the two rhodium atoms are bridged by two thiolato ligands with no metal-metal bonds and the pentamethylcyclopentadienyl and chlorido ligands are oriented syn to each other, an uncommon conformation for such dinuclear complexes. These structural features were rationalized using DFT calculations. Additionally, the antiproliferative activity of the complexes was evaluated against the cancerous A2780 (cisplatin sensitive) and A2780cisR (cisplatin resistant) human ovarian cell lines and on the noncancerous HEK293 human embryonic kidney cells. All complexes were found to be active and the cationic iridium complexes , and are particularly cytotoxic, with IC50 values in the nanomolar range (IC50 < 0.1 μM). The catalytic activity of the complexes for the oxidation of glutathione (GSH) to GSSG was evaluated by NMR spectroscopy.

  1. Seismic Performance Analysis of Bridge Structure Based on Energy Balance%基于能量平衡的桥梁结构抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    柳春光; 焦伟玲; 张士博

    2016-01-01

    The static elastic-plastic method based on energy balance is a new method of seismic performance evaluation which introduces the concept of energy balance to the Pushover method .This method has already been used in the con-struction field ,but it is still lack of research in the field of bridge .In this paper ,first the bridge piers are pushed by three typical ground motions .Second ,the results of calculation are compared to two traditional Pushover methods using linear distribution ,the uniform distribution and nonlinear dynamic response analysis .Last ,quantified performance levels are used to evaluate the seismic response of bridge structure .It shows that the results obtained from this method are more similar to the results from the nonlinear dynamic response analysis .The results of damage state estimation of two methods are uniform .Therefore ,Pushover method based on energy balance can be used effectively to estimate the seismic re-sponse of bridge structure .%基于能量平衡的静力弹塑性方法是将能量平衡的概念引入到Pushover方法中,对结构进行抗震性能评价的新方法。该方法在建筑领域已有一定的应用,但是在桥梁领域相关的研究仍比较缺乏。利用该方法对三条典型地震动作用下桥梁的桥墩进行基于能量平衡的推覆分析,并将计算结果同倒三角分布模式、均匀分布模式下的传统Pushover方法以及时程分析的结果进行比较。最后,利用量化性能水准对基于能量平衡的Pushover方法的结果和时程分析的结果进行抗震性能评估。结果表明,基于能量平衡的Pushover方法和非线性时程分析方法所得到的结果更加接近,这两种方法对桥墩破坏程度的评估结果相同,因此,基于能量平衡的Pushover方法能够对桥梁结构进行更有效地抗震性能评估。

  2. New family of thiocyanate-bridged Re(IV)-SCN-M(II) (M = Ni, Co, Fe, and Mn) heterobimetallic compounds: synthesis, crystal structure, and magnetic properties.

    Science.gov (United States)

    González, Ricardo; Acosta, Alvaro; Chiozzone, Raúl; Kremer, Carlos; Armentano, Donatella; De Munno, Giovanni; Julve, Miguel; Lloret, Francesc; Faus, Juan

    2012-05-21

    The heterobimetallic complexes of formula [(Me(2)phen)(2)M(μ-NCS)Re(NCS)(5)]·CH(3)CN [Me(2)phen = 2,9-dimethyl-1,10-phenanthroline and M = Ni (1), Co (2), Fe (3), and Mn (4)] have been prepared, and their crystal structures have been determined by X-ray diffraction on single crystals. Compounds 1-4 crystallize in the monoclinic C2/c space group, and their structure consists of neutral [(Me(2)phen)(2)M(μ-NCS)Re(NCS)(5)] heterodinuclear units with a Re-SCN-M bridge. Each Re(IV) ion in this series is six-coordinated with one sulfur and five nitrogen atoms from six thiocyanate groups building a somewhat distorted octahedral environment, whereas the M(II) metal ions are five-coordinated with four nitrogen atoms from two bidentate Me(2)phen molecules and a nitrogen atom from the bridging thiocyanate describing distorted trigonal bipyramidal surroundings. The values of the Re···M separation through the thiocyanate bridge in 1-4 vary in the range 5.903(1)-6.117(3) Å. The magnetic properties of 1-4 as well as those of the parent mononuclear Re(IV) compounds (NBu(4))(2)[Re(NCS)(6)] (A1) (NBu(4)(+) = tetra-n-butylammonium cation) and [Zn(NO(3))(Me(2)phen)(2)](2)[Re(NCS)(5)(SCN)] (A2) were investigated in the temperature range 1.9-300 K. Weak antiferromagnetic interactions between the Re(IV) and M(II) ions across the bridging thiocyanate were found in 1-4 [J = -4.3 (1), -2.4 (2), -1.8 (3), and -1.2 cm(-1) (4), the Hamiltonian being defined as Ĥ = -JŜ(Re)·Ŝ(M)]. The magnetic behavior of A2 is that of a magnetically diluted Re(IV) complex with a large and positive value of the zero-field splitting for the ground level (D(Re) = +37.0 cm(-1)). In the case of A1, although its magnetic behavior is similar to that of A2 in the high-temperature range (D(Re) being +19.0 cm(-1)), it exhibits a weak ferromagnetism below 3.0 K with a canting angle of 1.3°.

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

    Science.gov (United States)

    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).

  4. Some remarks on the influence of temperature-variations, non-linearities, repeatability and ageing on modal-analysis for structural health monitoring of real bridges

    Directory of Open Access Journals (Sweden)

    Maas Stefan

    2015-01-01

    Full Text Available Structural Health Monitoring (SHM intends to identify damage by changes of characteristics as for instance the modal parameters. The eigenfrequencies, mode-shapes and damping-values are either directly used as damage indicators or the changes of derived parameters are analysed, such as e.g. flexibilities or updated finite element models. One common way is a continuous monitoring under environmental excitation forces, such as wind or traffic, i.e. the so-called output-only modal analysis. Alternatively, a forced measured external excitation in distinct time-intervals may be used for input-output modal analysis. Both methods are limited by the precision or the repeatability under real-life conditions at site. The paper will summarize several field tests of artificially step-by-step damaged bridges prior to their final demolishment and it will show the changes of eigenfrequencies due to induced artificial damage. Additionally, some results of a monitoring campaign of a healthy bridge in Luxembourg are presented. Reinforced concrete shows non-linear behaviour in the sense that modal parameters depend on the excitation force amplitude, i.e. higher forces lead often to lower eigenfrequencies than smaller forces. Furthermore, the temperature of real bridges is neither constant in space nor in time, while for instance the stiffness of asphalt is strongly dependant on it. Finally, ageing as such can also change a bridge’s stiffness and its modal parameters, e.g. because creep and shrinkage of concrete or ageing of elastomeric bearing pads influence their modulus of elasticity. These effects cannot be considered as damage, though they influence the measurement of modal parameters and hinder damage detection.

  5. Salt bridges: geometrically specific, designable interactions.

    Science.gov (United States)

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

    2011-03-01

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

  6. Structure Design of Basket Handle Arch Bridge of Zhengzhou-Xi'an High-speed Railway%郑州至西安铁路客运专线提篮拱桥结构设计特点

    Institute of Scientific and Technical Information of China (English)

    李义发

    2015-01-01

    尼尔森体系提篮拱桥造型美观,可一孔简支,主桥短,建筑高度低,跨越能力强,结构的竖、横向刚度大,适应整体桥面,造价经济,施工养护方便,设计成系列孔跨应用到铁路客运专线前景广阔,经济和社会效益显著。文中从国内外拱桥的现状出发,介绍了尼尔森提篮拱特征,并结合工程实例介绍了尼尔森提篮拱的构造设计。%Nielsen system basket arch bridge has attractive appearance and can be designed as a single-span bridge that will be simply supported.The length of main bridge of the type of the arch bridge is short,building height is low,spanning capacity is great,vertical and lateral stiffness of the structure is strong,and the bridge is also adapt to the overall bridge deck,cost-effectiveness,easy construction and maintenance.If the bridge is designed to have series of span of different length for selection and applied to the passenger dedicated railway line,it will have wide vista of application and the economic and social benefits will be significant.From the present situation of the arch bridge at home and a-broad,this paper introduces the characteristics and structure of nelson basket handle arch combined with an engineering example.

  7. Synthesis and Crystal Structure of the Ladder-like Organotin Complex: μ-pentaoxygen bridged penta(bis-benzyltin) bis-salicylate

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-Qiu; CHEN Zhi-Min; ZENG Rong-Ying; KUANG Dai-Zhi; FENG Yong-Lan; ZHANG Fu-Xing

    2005-01-01

    A novel organotin complex of μ-pentaoxygen bridged penta(bis-benzyltin) bis- salicylate has been synthesized by the reaction of bis-benzyltin oxide and salicylic acid and its struc- ture has been determined by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 1.7206(5), b = 2.1401(6), c = 2.1488(6) nm, β = 93.325(5)o, V = 7.899(4) nm3, Z = 4, Dc = 1.564 g/cm3, μ(MoKα) = 16.17 cm-1, Mr = 1859.94, F(000) = 3692, R1 = 0.0755 and wR2 = 0.1557. According to structural analysis, the coordination geometry of tin is a distorted trigonal bipyramid, and the ladder-like structure is shaped by four Sn2O2 planar four-membered rings.

  8. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex K3(TMS)2(H2O)2Cr(CN)6 [TMS = Tetramethylene Sulfone

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; CHE Yun-Xia; ZHENG Ji-Min

    2005-01-01

    The cyano-bridged bimetallic complex K3(TMS)2(H2O)2Cr(CN)6 with three- dimensional microporous structure was synthesized and characterized. The title complex (C14H20CrK3N, Mr = 601.78) crystallizes in monoclinic, space group C2/c with a = 14.357(4), b = 9.331(3), c = 19.180(6)(A), β = 96.754(5)o, V = 2551.6(13) (A)3, Z = 4, Dc = 1.567 g/m3, μ(MoKα) = 1.141 mm-1, F(000) = 1228, the final R = 0.0440 and wR = 0.0990 for 1760 observed reflections (I > 2σ(I)). In the crystal, two [Cr(CN) 6]3- units, four K+ ions and two oxygen atoms of two TMS molecules are linked to form a sixteen-membered ring and an extended three-dimensional structure.

  9. Identification of minute damage in composite bridge structures equipped with fiber optic sensors using the location of neutral axis and finite element analysis

    Science.gov (United States)

    Li, Xi; Glisic, Branko

    2016-04-01

    By definition, the neutral axis of a loaded composite beam structure is the curve along which the section experiences zero bending strain. When no axial loading is present, the location of the neutral axis passes through the centroid of stiffness of the beam cross-section. In the presence of damage, the centroid of stiffness, as well as the neutral axis, shift from the healthy position. The concept of neutral axis can be widely applied to all beam-like structures. According to literature, a change in location of the neutral axis can be associated with damage in the corresponding cross-section. In this paper, the movement of neutral axis near locations of minute damage in a composite bridge structure was studied using finite element analysis and experimental results. The finite element model was developed based on a physical scale model of a composite simply-supported structure with controlled minute damage in the reinforced concrete deck. The structure was equipped with long-gauge fiber optic strain and temperature sensors at a healthy reference location as well as two locations of damage. A total of 12 strain sensors were installed during construction and used to monitor the structure during various loading events. This paper aims to explain previous experimental results which showed that the observed positions of neutral axis near damage locations were higher than the predicted healthy locations in some loading events. Analysis has shown that finite element analysis has potential to simulate and explain the physical behavior of the test structure.

  10. Spin crossover and polymorphism in a family of 1,2-bis(4-pyridyl)ethene-bridged binuclear iron(II) complexes. A key role of structural distortions.

    Science.gov (United States)

    Matouzenko, Galina S; Jeanneau, Erwann; Verat, Alexander Yu; Bousseksou, Azzedine

    2011-10-07

    Two polymorphic modifications 1 and 3 of binuclear compound [{Fe(dpia)(NCS)(2)}(2)(bpe)] and pseudo-polymorphic modification [{Fe(dpia)(NCS)(2)}(2)(bpe)]·2CH(3)OH (2), where dpia = di-(2-picolyl)amine, bpe = 1,2-bis(4-pyridyl)ethene, were synthesized, and their structures, magnetic properties, and Mössbauer spectra were studied. Variable-temperature magnetic susceptibility measurements of three binuclear compounds show different types of magnetic behaviour. The complex 1 exhibits a gradual two-step spin crossover (SCO) suggesting the occurrence of the mixed [HS-LS] (HS: high spin, LS: low spin) pair at the plateau temperature (182 K), at which about 50% of the complexes undergoes a thermal spin conversion. The complex 2 displays an abrupt full one-step spin transition without hysteresis, centred at about 159 K. The complex 3 is paramagnetic over the temperature range 20-290 K. The single-crystal X-ray studies show that all three compounds are built up from the bpe-bridged binuclear molecules. The structure of 1 was solved for three spin isomers [HS-HS], [HS-LS], and [LS-LS] at three temperatures 300 K, 183 K, and 90 K. The crystal structures for 2 and 3 were determined for the [HS-HS] complexes at room temperature. The analysis of correlations between the structural characteristics and different types of magnetic behaviour for new 1-3 binuclear complexes, as well as for previously reported binuclear compounds, revealed that the SCO process (occurrence of full one-step, two-step, or partial (50%) SCO) is specified by the degree of distortion of the octahedral geometry of the [FeN(6)] core, caused by both packing and strain effects arising from terminal and/or bridging ligands. The comparison of the magnetic properties and the networks of intra- and inter-molecular interactions in the crystal lattice for the family of related SCO binuclear compounds suggests that the intermolecular interactions play a predominant role in the cooperativeness of the spin transition

  11. Performance-Based Seismic Financial Risk Assessment for Bridge Structure%桥梁结构基于性能的地震经济风险评估

    Institute of Scientific and Technical Information of China (English)

    张凯; 朱晞; 倪永军; 江辉

    2011-01-01

    A performance-based practical procedure is established for the direct seismic financial risk assessment to bridge structure in China.According to the code seismic fortification, the seismic hazard is determined using the earthquake intensity measure and a modified capacity-spectrum method is applied to determine the seismic demand levels corresponding to the damage states of bridge structure.The seismic financial risk for bridge structure can be quantified with the expected annual loss by integrating bridge damage fragility and loss ratio with seismic hazard.The method is applied to assess the seismic financial risk to an urban rail transit bridge using OpenSees simulation platform.The result indicates that the direct seismic financial risk is mainly resulted from minus damage and intermediate damage with relative high annual frequency, which takes 82.4% of the total under scenario earthquakes.And the verification shows that the procedure provides a relative conservative outcome of the seismic financial risk assessment in such a way that the relative errors tend to decrease at lower annual frequencies in comparison with that from the incremental dynamic analysis.%针对我国桥梁结构的地震直接经济风险评估,建立基于件能的实用评估方法.规范设防下利用地震动参数确定地震危险件,将改进能力谱方法用于确定桥梁结构各损伤状态的地震需求水平,结合桥梁损伤脆弱性以及相应的损失比,使桥梁结构的地震经济风险定量蛙表达为年预期损失形式.并借助OpenSees地震工程仿真平台应用本方法对一座城市轨道交通桥梁进行地震经济风险订估.结果表明,在设定地震下桥梁结构的地震直接经济风险损失主要来自年超越概率较高的轻微破坏和中等破坏,约占风险损火的82.4%;而运用增量动力分析对该评估方法的验证结果表明,该方法的评估结果与增量动力分析结果相比较为保守,二者相对误差随

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

    Science.gov (United States)

    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.

  13. Synthesis, Crystal Structure and Magnetic Properties of a Novel Azide-bridged Copper(Ⅱ) Coordination Polymers Containing Nitroxy Nitroxide

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Fang; ZHANG Yong-Hua; WANG Li-Ya

    2011-01-01

    A novel azide-bridged copper(Ⅱ) coordination polymer, [Cu3(NITpPy)4(N3)6]n (NITpPy = 4-pyridyl-4,4,5,5-tetramethylimidazline-3-oxide-1-oxyl), was structurally and magnetically characterized. It crystallizes in the triclinic space group P with a = 7.6932(10), b = 14.5556(19), c = 16.122(2) , α = 108.443(2), β = 95.251(2), γ = 104.236(2)°, V = 1631.7(4) 3, C48H64Cu3N30O8, Mr = 1379.87, Z = 1, Dc = 1.404 g/cm3, μ(MoKα) = 1.041 mm-1, F(000) = 713, the R = 0.0510 and wR = 0.1185 for 4285 observed reflections with I 2σ(I). X-ray analysis reveals that the Cu(Ⅱ) ions are linked by nitrogen atom of μ1,1 azido ligands to form a Cu-Cu-Cu unit. The units are linked by μ1,3 azido ligands through a bridging style to form a one-dimensional coordination polymer. The variable-temperature magnetic susceptibility data of the complex show ferromagnetic interactions in the complex.

  14. Syntheses, Structures and Fluorescent Properties of Copper(II) and Manganese(II) Helical Complexes Bridged by 4,4'-Dipyridylsulfide

    Institute of Scientific and Technical Information of China (English)

    LI Jun-Xia; DU Zhong-Xiang

    2012-01-01

    Two isostructural helical coordination polymers, {[Cu(dps)2(Hssa)-(H2O)2]'3H2O}n (1) and {[Mn(dps)2(Hssa)(H2O)2]'2H2O}n (2), have been synthesized by the solvothermal reaction of dps and Hsssa with CuCI2 or Mn(CH3COO)2 (dps = 4,4'-dipyridylsulfide, H3ssa -- 5- sulfosalicylic acid). Both compounds crystallize in monoclinic, space group P21/n. In either complex, the central metal ion (Cu11 for compound 1 and MnIt for compound 2) is surrounded by one Hssa2- ligand, two coordinated aquas and three dps molecules with a N303 donor set in a distorted octahedral coordination geometry. Half of the dps is monodentate and another half acts as μ2-bridging ligands. It is through the bridging function of dps that the neighbouring metal centers are connected and a one-dimensional helical structure of compound 1 or 2 forms. Fluorescence studies indicate that compounds 1 and 2 have blue emission bands centered at 403 and 405 nm, respectively.

  15. Synthesis and Crystal Structure of a New One-dimensional Zn(II) Nitronyl Nitroxide Complex Bridged by Pyridine-2,4-dicarboxylate Anion

    Institute of Scientific and Technical Information of China (English)

    GAO Dong-Zhao; LI Li-Cun; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping

    2006-01-01

    A new one-dimensional (1-D) Zn(II) nitronyl nitroxide complex bridged by pyri- dine-2,4-dicarboxylate anion, [Zn(NIT4Py)(2,4-PDA)(H2O)2]n (NIT4Py = 2-(4'-pyridyl)-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide and 2,4-PDA = pyridine-2,4-dicarboxylate anion), has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.834(2), b = 7.4376(10), c = 18.295(3) (A), β = 102.848(2)°, V = 2233.2(5)(A)3, C19H23N4O8Zn, Mr = 500.78, Dc = 1.489 g/cm3, μ(MoKα) = 1.152 mm-1, F(000) = 1036, Z = 4, the final R = 0.0390 and wR = 0.0915 for 3234 observed reflections. In the complex, each zinc(II) ion is six-coordinated by one nitrogen atom of the radical ligand (NIT4Py), one nitrogen atom and two oxygen atoms of two 2,4-PDA anions and two oxygen atoms of two water molecules. Each 2,4-PDA anion bridges two Zn(II) ions via a tridentate mode into a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.

  16. Examples of Solutions for Steel-Concrete Composite Structures in Bridge Engineering / Przykłady Konstrukcji Zespolonych W Budownictwie Mostowym

    Science.gov (United States)

    Flaga, Kazimierz; Furtak, Kazimierz

    2015-03-01

    The aim of the article [1] was to discuss the application of steel-concrete composite structures in bridge engineering in the aspect of structural design, analysis and execution. It was pointed out that the concept of steel-concrete structural composition is far from exhausted and new solutions interesting from the engineering, scientific and aesthetic points of view of are constantly emerging. These latest trends are presented against the background of the solutions executed in Poland and abroad. Particular attention is focused on structures of double composition and steel-concrete structures. Concrete filled steel tubular (CFST) structures are highlighted. W artykule [1] omówiono problemy konstrukcyjne, obliczeniowe i realizacyjne, związane z zastosowaniem konstrukcji zespolonych stal-beton w mostownictwie. Wskazano tam, że idea konstrukcyjnego zespolenia stali z betonem jest jeszcze daleka do wyczerpania i że wciąż pojawiają się nowe rozwiązania interesujące z inżynierskiego, naukowego i estetycznego punktu widzenia. W artykule niniejszym pokazano te nowoczesne trendy na tle rozwiązań zrealizowanych w Polsce i na świecie. Szczególną uwagę poświęcono konstrukcjom podwójnie zespolonym oraz konstrukcjom stalowobetonowym. Wyeksponowano tu szczególnie konstrukcje z rur stalowych wypełnionych betonem, typu CFST. Dają one nadzieję na ich szersze zastosowanie w warunkach polskich.

  17. Demixing transition, structure, and depletion forces in binary mixtures of hard-spheres: the role of bridge functions.

    Science.gov (United States)

    López-Sánchez, Erik; Estrada-Álvarez, César D; Pérez-Ángel, Gabriel; Méndez-Alcaraz, José Miguel; González-Mozuelos, Pedro; Castañeda-Priego, Ramón

    2013-09-14

    Asymmetric binary mixtures of hard-spheres exhibit several interesting thermodynamic phenomena, such as multiple kinds of glassy states. When the degrees of freedom of the small spheres are integrated out from the description, their effects are incorporated into an effective pair interaction between large spheres known as the depletion potential. The latter has been widely used to study both the phase behavior and dynamic arrest of the big particles. Depletion forces can be accounted for by a contraction of the description in the multicomponent Ornstein-Zernike equation [R. Castañeda-Priego, A. Rodríguez-López, and J. M. Méndez-Alcaraz, Phys. Rev. E 73, 051404 (2006)]. Within this theoretical scheme, an approximation for the difference between the effective and bare bridge functions is needed. In the limit of infinite dilution, this difference is irrelevant and the typical Asakura-Osawa depletion potential is recovered. At higher particle concentrations, however, this difference becomes important, especially where the shell of first neighbors is formed, and, as shown here, cannot be simply neglected. In this work, we use a variant of the Verlet expression for the bridge functions to highlight their importance in the calculation of the depletion potential at high densities and close to the spinodal decomposition. We demonstrate that the modified Verlet closure predicts demixing in binary mixtures of hard spheres for different size ratios and compare its predictions with both liquid state and density functional theories, computer simulations, and experiments. We also show that it provides accurate correlation functions even near the thermodynamic instability; this is explicitly corroborated with results of molecular dynamics simulations of the whole mixture. Particularly, our findings point toward a possible universal behavior of the depletion potential around the spinodal line.

  18. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

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

    2012-01-01

    , considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  19. Ligand effects on the structure and magnetic properties of alternating copper(II) chains with 2,2'-bipyrimidine- and polymethyl-substituted pyrazolates as bridging ligands.

    Science.gov (United States)

    Castro, Isabel; Calatayud, M Luisa; Barros, Wdeson P; Carranza, José; Julve, Miguel; Lloret, Francesc; Marino, Nadia; De Munno, Giovanni

    2014-06-02

    A novel series of heteroleptic copper(II) compounds of formulas {[Cu2(μ-H2O)(μ-pz)2(μ-bpm)(ClO4)(H2O)]ClO4·2H2O}n (1), {[Cu2(μ-H2O)(μ-3-Mepz)2(μ-bpm)](ClO4)2·2H2O}n (2), and {[Cu2(μ-OH)(μ-3,5-Me2pz)(μ-bpm)(H-3,5-Me2pz)2](ClO4)2}n (3) [bpm = 2,2'-bipyrimidine, Hpz = pyrazole, H-3-Mepz = 3-methylpyrazole, and H-3,5-Me2pz = 3,5-dimethylpyrazole] have been synthesized and structurally characterized by X-ray diffraction methods. The crystal structures of 1 and 2 consist of copper(II) chains with regular alternating bpm and bis(pyrazolate)(aqua) bridges, whereas that of 3 is made up of copper(II) chains with regular alternating bpm and (pyrazolate)(hydroxo) bridges. The copper centers are six- (1) or five-coordinate (2) in axially elongated, octahedral (1) or square-pyramidal (2) environments in 1 and 2, whereas they are five-coordinate in distorted trigonal-bipyramidal surroundings in 3. The values of the copper-copper separations across the bpm/pyrazolate bridges are 5.5442(7)/3.3131(6) (1), 5.538(1)/3.235(1) (2), and 5.7673(7)/3.3220(6) Å (3). The magnetic properties of 1-3 have been investigated in the temperature range of 25-300 K. The analysis of their magnetic susceptibility data through the isotropic Hamiltonian for an alternating antiferromagnetic copper(II) chain model [H = -J∑i=1-n/2 (S2i·S2i-1 + αS2i·S2i+1), with α = J'/J and Si = SCu = 1/2] reveals the presence of a strong to moderate antiferromagnetic coupling through the bis(pyrazolate)(aqua) [-J = 217 (1) and 215 cm(-1) (2)] and (pyrazolate)(hydroxo) bridges [-J = 153 cm(-1) (3)], respectively, whereas a strong to weak antiferromagnetic coupling occurs through the bis-bidentate bpm [-J' = 211 (1), 213 (2), and 44 cm(-1) (3)]. A simple orbital analysis of the magnetic exchange interaction within the bpm- and pyrazolate-bridged dicopper(II) fragments of 1-3 visualizes the σ-type pathways involving the (dx(2)-y(2)) (1 and 2) or d(z(2)) (3) magnetic orbitals on each metal ion, which account

  20. Crystal structure of dimeric cardiac L-type calcium channel regulatory domains bridged by Ca[superscript 2+]·calmodulins

    Energy Technology Data Exchange (ETDEWEB)

    Fallon, Jennifer L.; Baker, Mariah R.; Xiong, Liangwen; Loy, Ryan E.; Yang, Guojun; Dirksen, Robert T.; Hamilton, Susan L.; Quiocho, Florante A.; (Baylor); (Rochester-Med)

    2009-11-10

    Voltage-dependent calcium channels (Ca(V)) open in response to changes in membrane potential, but their activity is modulated by Ca(2+) binding to calmodulin (CaM). Structural studies of this family of channels have focused on CaM bound to the IQ motif; however, the minimal differences between structures cannot adequately describe CaM's role in the regulation of these channels. We report a unique crystal structure of a 77-residue fragment of the Ca(V)1.2 alpha(1) subunit carboxyl terminus, which includes a tandem of the pre-IQ and IQ domains, in complex with Ca(2+).CaM in 2 distinct binding modes. The structure of the Ca(V)1.2 fragment is an unusual dimer of 2 coiled-coiled pre-IQ regions bridged by 2 Ca(2+).CaMs interacting with the pre-IQ regions and a canonical Ca(V)1-IQ-Ca(2+).CaM complex. Native Ca(V)1.2 channels are shown to be a mixture of monomers/dimers and a point mutation in the pre-IQ region predicted to abolish the coiled-coil structure significantly reduces Ca(2+)-dependent inactivation of heterologously expressed Ca(V)1.2 channels.

  1. Industrial steel hall with bridge grane

    OpenAIRE

    Jurejevčič, Nejc

    2016-01-01

    In introduction this diploma thesis describes all main characteristics of (single block)? industrial steel hall with bridge crane. Load arrangement on the supporting structure which covers general actions (snow load and wind action), self-weight and dynamic load of bridge crane was designed with moment resisting frame in transverse direction and frame with concentric diagonal bracing in longitudinual direction. Actions induced by crane bridge was considered in design of runway beam. Steel hal...

  2. 23 CFR 650.805 - Bridges not requiring a USCG permit.

    Science.gov (United States)

    2010-04-01

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

  3. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...

  4. Seismic response of steel suspension bridge

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  5. Synthesis, structure and magnetic properties of 5-(4-Sulfophenylazo) salicylate-bridged 1D coordination polymers containing linear trinuclear metal clusters

    Science.gov (United States)

    Liu, Hong; Song, Li-jun; Ju, Zhan-feng; Li, Wei; Zhang, Jie

    2008-03-01

    Three new trinuclear metal complexes with an azobenzene-containing ligand [M 3(Sasa) 2(Py) 2(H 2O) 8] (Na 2HSasa = 5-(4-Sulfophenylazo) salicylic acid disodium salt; Py = pyridine; M = Cu, Co, Zn), are synthesized through the interface diffusion and structurally characterized by single crystal X-ray diffraction, XRPD analysis and spectral methods. The metal ions in distorted octahedral coordination environments are connected by Sasa ligands to form 1D coordination polymer chain containing the linear trinuclear units with single syn-anti carboxylate bridges. The extensive hydrogen bonding interactions hold these chains together into 3D supramolecular network. Weak antiferromagnetic interactions between adjacent metal ions with J = -1.85 cm -1 and J = -2.81 cm -1 dominate the magnetic properties of Cu(II) and Co(II) complexes, separately.

  6. Synthesis and Crystal Structure of a Spiral-chain Manganese(Ⅲ) Complex Containing Azide Bridge, [Mn(bzan)N3]n

    Institute of Scientific and Technical Information of China (English)

    冯云龙

    2002-01-01

    The title complex, C22H22MnN5O2, crystallizes in orthorhombic system, space group P212121 with a = 6.887(1), b = 11.718(2), c = 25.721(5) (A。), V = 2075.7(7) (A。)3, Z = 4, Mr = 443.39, F(000) = 920, Dc = 1.419 g/cm3 and ( = 0.665mm(1 (MoK(). The structure was refined to R = 0.0593 and wR = 0.1427 for 3576 observed reflections with I ≥ 2((I). The Mn(Ⅲ) atom is coordinated to one bzan2-[bzan2- = N,N-ethylenebis(benzoylacetoneiminato)] ligand binding in the equatorial mode and two N3- ions in the axial positions. The azide acts as a trans-μ-(1, 3) bridge, resulting in an infinite helical chain propagating along the b axis.

  7. 桥梁加铺结构层方案研究%Research for the Overlay Structure Layer Program of Bridges

    Institute of Scientific and Technical Information of China (English)

    王婷宇

    2014-01-01

    Engineering background with a bridge span of 8 m which need top up 30.5 cm,this pa-per intends to use the way that directly paving the structural layer instead of jacking,make it contact with the road surface.By theoretical calculations verified that the scheme is feasible,provide reference for simi-lar projects.%以耒宜高速公路需顶升30.5 cm 且跨径为8 m的桥梁为工程背景,拟采用不顶升,直接加铺结构层方式,使之与路面顺接。通过理论计算验证了该方案切实可行,为类似工程提供参考。

  8. Synthesis, crystal structure and photo luminescent property of a 3D metal-organic hybrid of Cd(II) constructed by two different bridging carboxylate

    Indian Academy of Sciences (India)

    Biswajit Bhattacharya; Rajdip Dey; Debajyoti Ghoshal

    2013-05-01

    A solvothermal reaction of cadmium (II) nitrate with succinic acid and isonicotinic acid creates a novel 3D metal-organic framework, [Cd3(isonicotinate)2(suc)2] (1). Single crystal X-ray structure determination reveals that complex 1 posses two crystallographically independent Cd(II) centres. The succinate anion acts here as a heptadented ligand and binds five Cd(II) centre simultaneously. The heptacoordinated Cd(II) centres are oxo-bridged by succinate moiety and the hexacoordinated metal centres are terminally connected through four different succinate moiety to make the overall 2D sheet arrangement. In unit cell, the ratio of hexadented Cd(II) and heptadented Cd(II) is 1:2. The new compound was also characterized by luminescence spectra and compared with the luminescence spectra of the pure isonicotinic acid.

  9. Rare-earth metal hydrides supported by silicon-bridged boratabenzene fluorenyl ligands: synthesis, structure and reactivity.

    Science.gov (United States)

    Wang, Chunhong; Xiang, Li; Leng, Xuebing; Chen, Yaofeng

    2017-01-24

    The reactions of rare-earth metal benzyl complexes supported by silicon-bridged boratabenzene fluorenyl ligands with PhSiH3 in toluene gave the corresponding dinuclear hydrides [{μ-[Me2Si(C13H8)(C5H4BNEt2)]}Ln(μ-H)(THF)]2 (3-Ln; Ln = La, Nd, Gd), wherein the rare-earth metal ions are linked by both silicon-bridged boratabenzene fluorenyl ligands and hydrido ligands. The reactivity of these hydrides toward unsaturated substrates was studied. Among these, alkynides [{μ-[Me2Si(C13H8)(C5H4BNEt2)]}Ln(μ-CCPh)]2 (4-Ln; Ln = La, Nd) were obtained via the σ-bond metathesis reaction, when 3-Ln (Ln = La, Nd) was treated with phenylacetylene. While reacting with 3-hexyne, the mono-addition product [{μ-[Me2Si(C13H8)(C5H4BNEt2)]}Ln]2(μ-H)[μ-C(Et)[double bond, length as m-dash]C(H)Et] (5-Ln; Ln = La, Nd) was formed. Further investigations on the reactivity of 3-La displayed that benzonitrile and tert-butyl isonitrile readily inserted into the La-H bonds, affording an azomethine complex [{μ-[Me2Si(C13H8)(C5H4BNEt2)]}La{μ-N[double bond, length as m-dash]C(H)Ph}]2 (6-La) and an N-tert-butylformimidoyl complex [{μ-[Me2Si(C13H8)(C5H4BNEt2)]}La{μ,η(2)-C(H)[double bond, length as m-dash]N(t)Bu}]2 (7-La), respectively. The reaction with N,N'-diisopropylcarbodiimide at room temperature or at 75 °C gave a dimeric complex [{μ-[Me2Si(C13H8)(C5H4BNEt2)]}La]2(μ-H)[μ-N((i)Pr)CHN((i)Pr)] (8-La) or a monomeric complex [Me2Si(C13H8)(C5H4BNEt2)]La[N((i)Pr)CHN((i)Pr)] (9-La), respectively.

  10. Advanced structural materials for the suspension bridge solution of the project to establish a permanent link over the strait of Gibraltar; Materiales estructurales para la solucion puente, relacionados con el proyecto de enlace fijo a traves del estrecho de Gibraltar

    Energy Technology Data Exchange (ETDEWEB)

    Galligo Esteve, J. M.

    2015-07-01

    In 1995, the Spanish-moroccan Mixed Committee for the Gibraltar Strait Fixed Link selected the excavated tunnel solution, as preferred to the suspension bridge one. This was based on detailed scientific and technical studies. Nonetheless, further geology studies on the tunnel layout have detected sections of difficult excavation, which would entail increases in the length, the term of execution and the cost of the tunnel. Taking this into account, and due to the important technology development in bridge construction that has taken place over the last 20 years, the paper presents a state-of-the-art of the most advanced structural materials (high performance concrete, ultra-high performance concrete, suspension cables, structural steel, reinforcing and prestressing steel, stainless steel) available for an eventual reconsideration of the suspension bridge solution for the Gibraltar Strait Fixed Link. (Author)

  11. Copper(II) complex as a precursor for formation of cyano-bridged pentanuclear FeIII-CuII bimetallic assembly: Synthesis, characterization, crystal structure and antibacterial activity

    Indian Academy of Sciences (India)

    SURACHAI KONGCHOO; KITTIPONG CHAINOK; ANOB KANTACHA; SUMPUN WONGNAWA

    2017-04-01

    [CuL(ClO ₄) ₂] (1) (L = 3,10-diisobutyl-1,3,5,8,10,12-hexaazacyclotetradecane) was synthesized by condensation reaction of ethylenediamine, formaldehyde and iso-butylamine in absolute ethanol. Characterization of 1 utilized various spectroscopic techniques, viz. elemental analysis, electrospray ionization-mass spectrometry (ESI-MS), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), diffuse reflectance spectroscopy (DRS) and thermogravimetric analysis (TGA). Based on these techniques, the structure of 1 was proposed as Cu(II) ion occupying octahedral geometry with four secondary amine nitrogens of the hexaazamacrocyclic ligand and two perchlorato anions. 1 was used as a precursor in the preparation of cyano-bridged bimetallic compound, [CuL] ₃ [Fe(CN) ₆] ₂•5H ₂O (2), by reaction with K ₃ [Fe(CN) ₆] in aqueous solution. Single-crystal X-ray analysis indicated that 2 crystallized in the monoclinic system with space group P21/n. The structure of 2 consisted of cyano-bridged FeIII-CuII pentanuclear molecules having two [Fe(CN) ₆] ³⁻ anions connected to three cis-[CuL] ²⁺ cations via two cis-cyanide ligands from each ferrate unit. In each of pentanuclear unit, the central [CuL] ²⁺ cation exhibited a distorted octahedral geometry while the other two units exhibited a distorted square pyramidal geometry. The room temperature magnetic moments of both complexes were measured to be 1.92 B.M. for 1 and 5.61 B.M. for 2. The in vitro antibacterial activity of 1 against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 strains were studied and compared with standard drugs, which showed moderate antibacterial activity compared with Penicillin and Gentamicin.

  12. [Edge effect of the plant community structure on land-bridge islands in the Thousand Island Lake].

    Science.gov (United States)

    Su, Xiao-Fei; Yuan, Jin-Feng; Hu, Guang; Xu, Gao-Fu; Yu, Ming-Jian

    2014-01-01

    The research was conducted on 29 land-bridge islands in the Thousand Island Lake (TIL), where long-term monitoring plots were set up during 2009-2010. The community attributes including species richness, Shannon index, plant mean height, plant mean diameter at breast height (DBH) and plant density along the edge-interior gradient from edge to interior forest were calculated to investigate the edge effect. The results showed that the species richness and Shannon index were affected through the whole gradient (larger than 50 m), while the range of edge effect was 20-30 m on mean plant height, and 10 m on plant density and mean DBH. Community attributes differed significantly among the edge gradients. The species richness and Shannon index peaked at the intermediate edge gradient. Plant density decreased and plant mean height increased along the edge to interior gradient. All five community attributes were significantly associated with the edge gradient, also different functional groups, evergreen or deciduous species, trees or shrubs, shade tolerant or shade intolerant species, were differentially influenced by the edge effect. It was demonstrated the influence of edge effect on the fragmented forest community varied with community attributes and functional groups.

  13. Land use patterns and landscape structures on the islands in Jeonnam Province’s Shinan County occasioned by the construction of mainland bridges

    Directory of Open Access Journals (Sweden)

    Jae-Eun Kim

    2016-06-01

    Full Text Available Land use in a specific region reflects the prevailing socioeconomic circumstances and cultures within that region. To this end, the current study analyzes the landscape structure of Shinan County using landscape indices based on land use to compare various socio-economic factors of the culture found on the islands of Shinan County. In addition, a cluster analysis was conducted to learn about the characteristics of islands exhibiting the same landscape structure. This analysis revealed that the landscape of the second largest island in Shinan County, Jido, was more fragmented than that of the biggest island Aphae. The cluster analysis led to the creation of three groups of islands exhibiting similar landscape structures. Group 1 is composed of the islands which are connected by a mainland bridge (called ‘yeonyukgyo’ in Korean. Group 2 and 3 also include the upper islands (those islands located in the northern area and lower islands (those islands located in the southern area in Shinan County. The presence of more advanced transportation systems and structures occasioned by their proximity to the island of Jido which was connected at an early date to the mainland ensured that the upper islands have historically been more frequently visited.

  14. 地震对桥梁的危害、抗震措施及结构振动控制%Earthquake Damage to Bridge,Aseismatic Measures and Structural Vibration Control

    Institute of Scientific and Technical Information of China (English)

    刘春; 刘长宏; 宋俊杰

    2011-01-01

    针对桥梁在地震中暴露出来的薄弱环节,通过慎重选择桥位,并对结构的薄弱部位予以局部加强,来提高桥梁的抗震能力。国内外多次地震经验证明,只要桥梁能满足场地有利、结构合理、整体性强、施工质量良好和措施得当,一般均能提高桥梁结构的抗震防灾能力。%On account of weak link of bridge exposed in earthquake,earthquake experience at home and abroad demonstrate that the bridge should be with aseismatic and disaster prevention capacity as long as the bridge can meet the requirements of advantageous site,reasonable structure,strong wholeness,good construction quality and appropriate measures.Improve the aseismatic capacity of the bridge by carefully selecting the bridge location and partially strengthening the weak part of the structure.

  15. MTMDs控制高速铁路简支箱梁桥车致振动噪声的研究%Structure-borne noise control with MTMDs for a high-speed railway simply supported box-girder bridge

    Institute of Scientific and Technical Information of China (English)

    张迅; 李小珍; 刘全民; 张志俊; 李亚东

    2013-01-01

    轨道不平顺性激励引起桥梁结构振动,进而向空间辐射噪声.为了探明多重调谐质量阻尼器(MTMDs)对桥梁结构噪声的影响,选取32 m双线混凝土简支箱梁为研究对象,建立了移动集中力-桥梁-MTMDs耦合振动模型,根据桥梁的挠曲频响函数,求取了MTMDs的最优控制参数.在此基础上,采用瞬态有限元法和声学边界元法研究了不同数量调谐质量阻尼器对桥梁的减振、降噪效果.研究结果表明:MTMDs能有效控制桥梁的最大振动响应;由于MTMDs仅对一阶竖弯频率处的结构振动控制有效,使得其对结构噪声的控制效果不甚明显,对近轨侧25 m处声场的平均降噪效果约0.5 dB.%When a train runs across a bridge,the bridge is excited by dynamic forces acting on it because of the track irregularities,and the structure-borne noise radiated by the bridge raises evidently.To explore the influence of multiple tuned mass dampers (MTMDs) on structure-borne noise,the dynamic behavior of a two-track simply supported box-girder bridge with a span of 32 m was simulated as a case study.Based on a moving forces-bridge-MTMDs coupling vibration model,the optimal MTMDs parameters were derived and calculated with the flexural frequency response functions of the bridge,and then,the vibration and noise control effectivenesses of the bridge with and without MTMDs were compared respectively by applying the transient FEM and the acoustic BEM.The results showed that MTMDs are an effective device in reducing dynamic responses of a box-girder bridge ; however,as the vibration control of MTMDs aims at the first flexural mode of the bridge,the structure-borne noise reduction is not as effective as the vibration reduction,and the average reduction of sound pressure level (SPL) is about 0.5 dB for the sound filed being 25 m far from the track.

  16. Assessment of the Reliability of Concrete Bridges

    DEFF Research Database (Denmark)

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

    a significant shift in emphasis for the highways authorities around the world away from the design of new structures over to maintaining the existing infrastructure. As a result, bridge owners are seeking improved ways of inspecting, assessing, maintaining and repairing their existing stock of bridges...... in the wake of ever increasing traffic loads and volumes, and an ageing population of bridges subject to various mechanisms of deterioration. The goal is to optimise the allocation of limited resources whilst maintaining their bridges in a safe and serviceable condition. Reliability analysis is one tool being...

  17. Evaluation method research on prestressed concrete bridges

    Institute of Scientific and Technical Information of China (English)

    HUANG Qiao; LIN Yang-zi; REN Yuan

    2008-01-01

    Considering the construction features of prestressed concrete bridge, the comprehensive evaluation method about the bridge damage conditions are studied. Particular attentions are paid on establishing a multi-level evaluation model for damaged prestressed concrete bridge, and the evaluation indices of the model as well as the rating standards are defined in the model. A normal relative function about the evaluation indices of each element is developed to calculate the relative degree, and for each element which is no sub-level elements. When evaluating the elements in sub-item level or index level of the model, the weights of elements that are pertained to one element are adopted, taking account of their deterioration degree. At the same time, the dam-age conditions of bridge are characterized by relative degree, element evaluation scale and structural technology mark of bridge ,so it agrees with Code for Maintenance of Highway Bridges and Culvers.

  18. A data management infrastructure for bridge monitoring

    Science.gov (United States)

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

    2015-04-01

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

  19. Floating liquid bridge charge dynamics

    Science.gov (United States)

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

    2016-01-01

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

  20. Bridges in Complex Networks

    CERN Document Server

    Wu, Ang-Kun; Liu, Yang-Yu

    2016-01-01

    A bridge in a graph is an edge whose removal disconnects the graph and increases the number of connected components. We calculate the fraction of bridges in a wide range of real-world networks and their randomized counterparts. We find that real networks typically have more bridges than their completely randomized counterparts, but very similar fraction of bridges as their degree-preserving randomizations. We define a new edge centrality measure, called bridgeness, to differentiate the importance of a bridge in damaging a network. We find that certain real networks have very large average and variance of bridgeness compared to their degree-preserving randomizations and other real networks. Finally, we offer an analytical framework to calculate the bridge fraction and average bridgeness for uncorrelated random networks with arbitrary degree distributions.

  1. 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.

    Science.gov (United States)

    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.

  2. Role of a salt bridge in the model protein crambin explored by chemical protein synthesis: X-ray structure of a unique protein analogue, [V15A]crambin-alpha-carboxamide.

    Science.gov (United States)

    Bang, Duhee; Tereshko, Valentina; Kossiakoff, Anthony A; Kent, Stephen B H

    2009-07-01

    We have used total chemical synthesis to prepare [V15A]crambin-alpha-carboxamide, a unique protein analogue that eliminates a salt bridge between the delta-guanidinium of the Arg(10) side chain and the alpha-carboxylate of Asn(46) at the C-terminus of the polypeptide chain. This salt bridge is thought to be important for the folding and stability of the crambin protein molecule. Folding, with concomitant disulfide bond formation, of the fully reduced [V15A]crambin-alpha-carboxamide polypeptide was less efficient than folding/disulfide formation for the [V15A]crambin polypeptide under a standard set of conditions. To probe the origin of this less efficient folding/disulfide bond formation, we separately crystallized purified synthetic [V15A]crambin-alpha-carboxamide and chemically synthesized [V15A]crambin and solved their X-ray structures. The crystal structure of [V15A]crambin-alpha-carboxamide showed that elimination of the Arg(10)-Asn(46) salt bridge caused disorder of the C-terminal region of the polypeptide chain and affected the overall 'tightness' of the structure of the protein molecule. These studies, enabled by chemical protein synthesis, strongly suggest that in native crambin the Arg(10)-Asn(46) salt bridge contributes to efficient formation of correct disulfide bonds and also to the well-ordered structure of the protein molecule.

  3. Structure Optimization of Large Double Feed Honing Stone Bridge%大型双进给珩磨头油石座的结构优化∗

    Institute of Scientific and Technical Information of China (English)

    侯运丰; 廖秋岩; 张龙波; 樊思敏

    2015-01-01

    对于大型珩磨机的珩磨头,珩磨头的刚度大小主要依靠油石座等零件的刚度大小来衡量。文章以大型双进给珩磨头油石座为研究对象,运用ANSYS软件对直径为ϕ400 mm的大型珩磨头油石座进行刚度模拟计算,在保证油石座基本尺寸不变的情况下,进行结构优化,并通过材料力学的理论计算验证其正确性,进而采用模拟计算与理论计算对比的方法,得出最佳油石座导向支柱数量为四个的结论,最终得出刚度优化方案,为大型珩磨头油石座刚度优化设计研究提供了参考。%For large honing head of honing machine, the rigidity of the honing head size mainly rely on oil-stone seat stiffness measured size. Based on the large double feed honing stone bridge as the research object, by using the ANSYS software to a diameter of 400 mm large honing stone stiffness simulation calculation, in guarantee under the condition of invariable oilstone seat basic size, structure optimization, and its correctness is proved by the theory of mechanics of materials, then adopt the method of simulation compared with the theoretical calculation, it is concluded that the best oilstone seat number for the four pillars of the conclu-sion, finally concluded that stiffness optimization scheme, for large honing stone bridge rigidity as reference for optimizing design and research.

  4. Heteronuclear, mixed-metal Ag(I)-Mn(II) coordination polymers with bridging N-pyridinylisonicotinohydrazide ligands: synthesis, crystal structures, magnetic and photoluminescence properties.

    Science.gov (United States)

    Bikas, Rahman; Hosseini-Monfared, Hassan; Vasylyeva, Vera; Sanchiz, Joaquín; Alonso, Javier; Barandiaran, Jose Manuel; Janiak, Christoph

    2014-08-21

    Mixed-metal dicyanoargentate-bridged coordination polymers of Ag(i)-Mn(ii) have been prepared and their structure and magnetic properties were determined. Reaction of manganese(ii) chloride and potassium dicyanoargentate(i) with (X)(pyridin-2-ylmethylene)isonicotinohydrazide ligands (HL(1) X = Ph, HL(2) X = Me, HL(3) X = H) produced the coordination polymer 2D-[Mn(μ-L(1))(Cl)(μ-NCAgCN)Mn0.5(CH3OH)]n (), 1D-{[Mn(L(2))(Cl)(μ-NCAgCN)Mn0.5(CH3OH)]CH3OH}n () and [Mn(L(3))(Cl)(μ-NCAgCN)Mn0.5(CH3OH)]n () in good yields. Trinuclear {Mn(μ-L(1))Mn(μ-L(1))Mn} and [Ag(CN)2](-) building units form a two-dimensional slab in and 1D strands in . Variable temperature magnetic susceptibility measurements showed that despite the long distance among the high spin Mn(ii) ions [10.4676(12) Å and 10.522(1) Å, for and , respectively], weak antiferromagnetic coupling takes place through the long NC-Ag-CN bridge. The best fit parameters to the model led to the magnetic coupling constant of J = -0.1 and J = -0.47 cm(-1) for and , respectively. The photoluminescence behaviour of compounds and was studied. The spectrum of compound shows a broad emission centered at about 450 nm and two excitation maxima at 270 and 310 nm.

  5. Two-Dimensional Simulation of Flow and Evaluation of Bridge Scour at Structure A-1700 on Interstate 155 over the Mississippi River near Caruthersville, Missouri

    Science.gov (United States)

    Huizinga, Richard J.

    2007-01-01

    The evaluation of scour at bridges throughout the State of Missouri has been ongoing since 1991, and most of these evaluations have used one-dimensional hydraulic analysis and application of conventional scour depth prediction equations. Occasionally, the complex conditions of a site dictate a more thorough assessment of the stream hydraulics beyond a one-dimensional model. This was the case for structure A-1700, the Interstate 155 bridge crossing the Mississippi River near Caruthersville, Missouri. To assess the complex hydraulics at this site, a two-dimensional hydrodynamic flow model was used to simulate flow conditions on the Mississippi River in the vicinity of the Interstate 155 structure A-1700. The model was used to simulate flow conditions for three discharges: a flood that occurred on April 4, 1975 (the calibration flood), which had a discharge of 1,658,000 cubic feet per second; the 100-year flood, which has a discharge of 1,960,000 cubic feet per second; and the project design flood, which has a discharge of 1,974,000 cubic feet per second. The project design flood was essentially equivalent to the flood that would cause impending overtopping of the mainline levees along the Mississippi River in the vicinity of structure A-1700. Discharge and river-stage readings from the flood of April 4, 1975, were used to calibrate the flow model. The model was then used to simulate the 100-year and project design floods. Hydraulic flow parameters obtained from the three flow simulations were applied to scour depth prediction equations to determine contraction, local pier, and abutment scour depths at structure A-1700. Contraction scour and local pier scour depths computed for the project design discharge generally were the greatest, whereas the depths computed for the calibration flood were the least. The maximum predicted total scour depth (contraction and local pier scour) for the calibration flood was 66.1 feet; for the 100-year flood, the maximum predicted total

  6. Vibration analysis of the Second Saikai Bridge—a concrete filled tubular (CFT) arch bridge

    Science.gov (United States)

    Yoshimura, Mistuhiro; Wu, Qingxiong; Takahashi, Kazuo; Nakamura, Shozo; Furukawa, Kazuyoshi

    2006-02-01

    Concrete-filled steel tubular (CFT) arch bridges have been rapidly developing in China since 1990. Research has focused on the static behavior, thermal stress and erection technique, however, and there has been very little research of natural vibrations and dynamic responses of these bridges. Japan's first CFT arch bridge in highway bridges, the Second Saikai Bridge, is now under construction in Nagasaki Prefecture. Furthermore, this bridge has a pedestrian bridge that is suspended under the girder, which is rare. Therefore, the natural vibration properties are examined, and the influence of pedestrian bridge structure on the natural vibration of main bridge is discussed first. Response analysis under a moving vehicle and pedestrian is carried out, and the response characteristics and response level are clarified. The natural vibrations and responses are compared to those of CFT arch bridges that have been constructed in China. Results show the fine performance of both main bridge and pedestrian bridge of the Second Saikai Bridge.

  7. Assessment of seismic performance of skew reinforced concrete box girder bridges

    Science.gov (United States)

    Abdel-Mohti, Ahmed; Pekcan, Gokhan

    2013-12-01

    The seismic vulnerability of highway bridges remains an important problem and has received increased attention as a consequence of unprecedented damage observed during several major earthquakes. A significant number of research studies have examined the performance of skew bridges under service and seismic loads. The results of these studies are particularly sensitive to modeling assumptions in view of the interacting parameters. In the present study, three-dimensional improved beam-stick models of two-span highway bridges with skew angles varying from 0° to 60° are developed to investigate the seismic response characteristics of skew box girder bridges. The relative accuracy of beam-stick models is verified against counterpart finite element models. The effect of various parameters and conditions on the overall seismic response was examined such as skew angle, ground motion intensity, soil condition, abutment support conditions, bridge aspect ratio, and foundation-base conditions. The study shows that the improved beam-stick models can be used to conduct accurate nonlinear time history analysis of skew bridges. Skew angle and interacting parameters were found to have significant effect on the behavior of skewed highway bridges. Furthermore, the performance of shear keys may have a predominant effect on the overall seismic response of the skew bridges.

  8. External Prestressing Bridge Reinforcement Technology Review

    Directory of Open Access Journals (Sweden)

    Zhu Hanbing

    2015-01-01

    Full Text Available Externally prestressed bridge can not only limit and reduce the cracks and deformation of the structure, improve the rigidity and bearing capacity of structure, improve the stress state of structure, but also have less interference for bridge operation when it is operating and have the good economic efficiency. This paper introduces the advantages and disadvantages of external prestressed strengthening technique, its calculation theory and construction technology described in detail, and finally the paper discusses the deficiency of existing research.

  9. Architectural engineering of FRP bridges

    OpenAIRE

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on architectural application of FRP's derived from the authors architectural practice.

  10. Architectural engineering of FRP bridges

    NARCIS (Netherlands)

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on archit

  11. Synthesis, crystal structure and magnetic properties of novel heterobimetallic malonate-bridged MIIReIV complexes (M = Mn, Fe, Co and Ni).

    Science.gov (United States)

    Cuevas, Alicia; Kremer, Carlos; Suescun, Leopoldo; Russi, Silvia; Mombrú, Alvaro W; Lloret, Francesc; Julve, Miguel; Faus, Juan

    2007-12-07

    Five novel ReIV-MII bimetallic complexes of formula [ReCl4(mu-mal)M(dmphen)2].MeCN [M = Co (1), Fe (2) and Ni (3)], [ReCl4(mu-mal)Ni(dmphen)(MeCN)2(H2O)].(MeCN)0.5(H2O)0.5 (4), and [ReCl4(mu-mal)Mn(dmphen)(H2O)2].dmphen.MeCN.H2O (5) (mal = malonate dianion, dmphen = 2,9-dimethyl-1,10-phenanthroline) have been synthesized, and the structures of 1, 2, 4, and 5 determined by single-crystal X-ray diffraction. The structures of 1 and 2 consist of neutral [ReCl4(mu-mal)M(dmphen)2] dinuclear units where the metal ions are linked through a malonate ligand which adopts simultaneously the bidentate (at ReIV) and monodentate (at MII) coordination modes. The bridging carboxylate-malonate group in them exhibits the anti-syn conformation. The rhenium atom is six-coordinated with four chloro atoms and two carboxylate-oxygens from a bidentate malonate group in a distorted octahedral environment. The M atom is five-coordinated being surrounded by four nitrogen atoms of two bidentate dmphen ligands and one oxygen atom of the malonato ligand. There are also ReIV(mu-mal)NiII dinuclear units in 4 with the same type of bridge, but the nickel atom is six-coordinated with one bidentate dmphen, two molecules of acetonitrile and one water molecule as peripheral ligands. Compound 5 is a neutral chain compound with regular alternating rhenium(IV) and manganese(II) ions. The [ReCl4(mal)]2- units in each chain act as bismonodenate ligands through two carboxylate-oxygen atoms toward [Mn(dmphen)(H2O)2]2+ entities. Variable-temperature magnetic measurements of 1-5 in the temperature range 2.0-300 K show the occurrence of weak antiferromagnetic interactions which are rationalized on the basis of the structural knowledge and simple orbital considerations. Very noticeable is compound 5, a ferrimagnetic chain with regular alternating ReIV and MnII cations.

  12. Synthesis and Structural Characterization of a New Cadmium(Ⅱ) Complex Bridged by Endo-norbornene-cis-5,6-dicarboxylic Acid

    Institute of Scientific and Technical Information of China (English)

    CAI Xiao-Qing; HU Mao-Lin; CHEN Fan

    2007-01-01

    A polynuclear complex [Cd(endc)(H2O)]n·nH2O (endc = endo-norbomene-cis5,6-dicarboxylate anion) has been synthesized by the hydrothermal reaction of cadmium nitrate tetrahydrate with endo-norbomene-cis-5,6-dicarboxylic acid in 1:1 molar ratio,and structurally characterized by single-crystal X-ray diffraction.It crystallizes in monoclinic,space group P21/c with a = 1.16471(7),b = 0.95334(7),c = 0.91109(9) nm,Z = 4,V= 1.01035(14)nm3,Dc.= 2.160 g/cm3,μ= 2.172 mm-1,F(000) = 648,R =0.0302 and wR = 0.0752.According to structural analysis,each Cd(Ⅱ) ion is coordinated to six O atoms from three endc anions and one water molecule,giving a distorted octahedral geometry.Two- dimensional layer arrangement of the title complex is constructed from the bridging nature of endc.It is worth notice that adjacent two-dimensional layers are joined together to form a three-dimensional supramolecular framework via intermolecular hydrogen bonding interactions.

  13. Influence of Bridge Structure Stiffness on the Dynamic Performance of High-Speed Train-Track-Bridge Coupled System%桥梁结构刚度对高速列车—轨道—桥梁耦合系统动力特性的影响

    Institute of Scientific and Technical Information of China (English)

    翟婉明; 王少林

    2012-01-01

    The dynamic performances of high-speed train-track bridge coupled system are significantly affected by the structure stiffness of bridge, which directly influences the running safety and ride comfort of a train on the bridge. Based on train-track-bridge dynamic interaction theory, the influences of structure stiffness of bridge on the dynamic responses of the coupled system were analyzed using the train-track-bridge dynamic simulation software TTBSIM2. 0, in which a simply supported bridge and double-block ballastless track both commonly used in high-speed railway were chosen to be the study object. Results show that when the stiffness of beam or the lateral stiffness of piers is insufficient, the major dynamic indexes of train and bridge increase dramatically with the decrease of the stiffness, and the running safety and the ride comfort of the train are deteriorated severely. In particular, the resonance of beam excited by passing train may occur if the vertical stiffness of beam is insufficient. When the structure stiffness of bridge satisfies the design code, the dynamic responses of train-bridge system vary little with the change of stiffness. The running speed and track irregularities become the main factors to influence the running safety and ride comfort of train.%桥梁结构刚度对高速列车—轨道—桥梁耦合系统的动力学特性具有重要的影响,直接关系到桥上列车的行车安全性和运行平稳性.基于列车—轨道—桥梁动力相互作用理论,以高速铁路常用的简支箱梁桥和双块式无砟轨道为研究对象,采用列车—轨道—桥梁动力学仿真通用软件TTBSIM2.0,研究桥梁结构刚度对高速列车—轨道—桥梁耦合系统动力性能的影响规律.结果表明:当桥梁梁体的刚度或者桥墩的横向刚度不足时,车辆和桥梁的相关动力性能指标将随着刚度的减少而急剧增大,严重影响列车过桥时的安全性和平稳性;当梁体垂向刚度不足

  14. Review of Energy Harvesters Utilizing Bridge Vibrations

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

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

  15. River ice jams at bridges

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D. [New Brunswick Dept. of Transportation, Fredericton, NB (Canada); Beltaos, S. [National Water Research Institute, Burlington, ON (Canada)

    2000-12-01

    Ice jamming, known to cause high water levels at even moderate river flows, is described as both the main and least understood source of ice-related bridge damages. This paper describes a joint study by the New Brunswick Department of Transportation, the Department of the Environment, local governments, and the National Water Research Institute, designed to address problems associated with the interaction of ice jams and bridges. The study consists of collecting information at each of four sites in New Brunswick including: historical data on ice jam locations, causes, and water levels; channel bathymetry, width and slope within each study centred at the respective bridge; and documentation of ice conditions throughout the ice season, including measurement of ice cover thickness, observation of breakup mechanisms, times, causes, characteristics and possible impacts of ice jam release. Data analysis will include determination of high stages due to ice jams or surges caused by upstream ice jam releases, scour potential of surges, and quantification of the structure's capacity to restrain ice movement and to cause jams. The principal objective of the study is to advance beyond empiricism and to develop rational design criteria for bridges by anticipating the effects of climate changes and by incorporating local meteorological and hydrometric records into bridge design for added safety.

  16. Bridging the gap between individual-level risk for HIV and structural determinants: using root cause analysis in strategic planning.

    Science.gov (United States)

    Willard, Nancy; Chutuape, Kate; Stines, Stephanie; Ellen, Jonathan M

    2012-01-01

    HIV prevention efforts have expanded beyond individual-level interventions to address structural determinants of risk. Coalitions have been an important vehicle for addressing similar intractable and deeply rooted health-related issues. A root cause analysis process may aid coalitions in identifying fundamental, structural-level contributors to risk and in identifying appropriate solutions. For this article, strategic plans for 13 coalitions were analyzed both before and after a root cause analysis approach was applied to determine the coalitions' strategic plans potential impact and comprehensiveness. After root cause analysis, strategic plans trended toward targeting policies and practices rather than on single agency programmatic changes. Plans expanded to target multiple sectors and several changes within sectors to penetrate deeply into a sector or system. Findings suggest that root cause analysis may be a viable tool to assist coalitions in identifying structural determinants and possible solutions for HIV risk.

  17. Renovation techniques for fatigue cracked orthotropic steel bridge decks

    NARCIS (Netherlands)

    de Jong, F.B.P.

    2007-01-01

    This dissertation presents the research into renovation techniques for orthotropic steel bridge decks. These techniques are needed to solve fatigue problems in the decks of these bridges, as several fatigue cracks have been detected in the deck structure of these bridges the last decade. A well-know

  18. Future Trends in Reliability-Based Bridge Management

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

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

  19. Syntheses, structures, and magnetic properties of three new cyano-bridged complexes based on the [Mn(CN)₆](³⁻) building block.

    Science.gov (United States)

    Zhang, Shao-Liang; Zhao, Xin-Hua; Wang, Xin-Yi

    2015-09-14

    With three pentadentate macrocyclic ligands, three new [Mn(CN)6](3-) based complexes, [Mn(L(N3O2))(H2O)]2[Mn(CN)6](ClO4)·3H2O (1), {[Mn(L(N5))]3[Mn(CN)6]2}n (2) and {[Mn(L(N5Me))]3[Mn(CN)6]2}n·10nH2O (3) (L(N3O2) = 2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene, L(N5) = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo-[12.3.1]octadeca-1(18),2,12,14,16-pentaene, L(N5Me) = 2,6-bis[1-(2-(N-methylamino)ethylimino)ethyl]-pyridine), have been synthesized and characterized structurally and magnetically. The structure of 1 was found to be a linear Mn2(II)Mn(III) trinuclear cluster with two Mn(II) capping groups and one Mn(III) ion connected via two trans-cyano groups. In contrast, compounds 2 and a3 re cyano-bridged 2D networks. Magnetic investigation revealed antiferromagnetic coupling between the Mn(III) and Mn(II) ions via the bridging cyanide groups. Complex 1 showed paramagnetic behavior down to 2.0 K with no sign of SMM behavior. The magnetic coupling constant of J = -1.63 cm(-1) with the Hamiltonian H = -2J(S(Mn(III))·SMn(II)1 + SMn(III)·S(Mn(II)2)) was obtained from the fitting of the magnetic susceptibility. For 2 and 3, ferrimagnetic ordering was observed with magnetic phase transition temperatures (Tc) being 7.5 K and 7.0 K, respectively. These compounds are rare examples of a small number of [Mn(CN)6](3-) based magnetic materials.

  20. 桥梁结构安全监测的动力响应法与评估系统%The Dynamic Response Method and Evaluation System on the Safety Monitoring of Bridge Structure

    Institute of Scientific and Technical Information of China (English)

    骆红军

    2011-01-01

    针对桥梁管理需要,在国内外现有桥梁管理系统的研究基础上,根据目前的技术条件及经济条件,对桥梁管理的安全动态监测系统进行了研究,明确地阐述了桥梁安全性动态监测与分析系统的概念,进行了该系统的结构设计,并对其核心部分结构安全性评估子系统进行了研究:给出了选取的监测参数、评估框架流程、参数识别方法、承载能力评定、荷载模式识别方法以及结构状态评估方法.该系统的使用可以使桥梁管理者及时了解桥梁结构的工作性能状况,正确作出桥梁维修决策,及时消除结构安全隐患.%The thesis does research on the safety-dynamic monitoring system of the bridge on the basis of the existing bridge management system, according to the current economic and technical conditions and the needs for bridge management at home and abroad. It elaborates on the concept of the safety-dynamic monitoring and evaluation system of the bridge, designs the structure of the system and discuss the safety evaluation subsystem, which gives the selected monitoring parameters, evaluation framework, parameter identification method, bearing capacity assessment, load carrying capacity of pattern recognition method and structural condition evaluation method. The use of the system can make bridges managers promptly understand the bridge structure work performance, correctly make bridge maintenance decision and timely to eliminate safety hidden troubles on structure.

  1. 某大跨石拱桥水淹状态结构验算及加固处理%Reinforcement Treatment and Structure Calculation for Stone Arch Bridge under Water Logging

    Institute of Scientific and Technical Information of China (English)

    董亮; 肖勃; 张炯

    2011-01-01

    Taking the Youyang Gongtan bridge as a background,the article uses the bridge structure finite element calculation model to simulate and analysis the structure safety of stone arch bridge under water logging.Combined with bridge reinforcement theory,the arti-cle proposes some method such as strengthen concrete and rebar implanting for the arching,arch springing and abutment to increase its loading ability.%文章以酉阳龚滩大桥为背景,采用桥梁结构有限元计算模型模拟分析库区石拱桥在蓄水后处于部分水淹状态下的结构安全性,并结合桥梁加固理论,对石拱桥的拱圈、拱脚及桥台提出相应的混凝土补强、植筋等加固措施,以提高其承载能力。

  2. Calculations in bridge aeroelasticity via CFD

    Energy Technology Data Exchange (ETDEWEB)

    Brar, P.S.; Raul, R.; Scanlan, R.H. [Johns Hopkins Univ., Baltimore, MD (United States)

    1996-12-31

    The central focus of the present study is the numerical calculation of flutter derivatives. These aeroelastic coefficients play an important role in determining the stability or instability of long, flexible structures under ambient wind loading. A class of Civil Engineering structures most susceptible to such an instability are long-span bridges of the cable-stayed or suspended-span variety. The disastrous collapse of the Tacoma Narrows suspension bridge in the recent past, due to a flutter instability, has been a big impetus in motivating studies in flutter of bridge decks.

  3. The structure of the SBP-Tag–streptavidin complex reveals a novel helical scaffold bridging binding pockets on separate subunits

    Energy Technology Data Exchange (ETDEWEB)

    Barrette-Ng, Isabelle H.; Wu, Sau-Ching; Tjia, Wai-Mui; Wong, Sui-Lam; Ng, Kenneth K. S., E-mail: ngk@ucalgary.ca [University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4 (Canada)

    2013-05-01

    The structure of the SBP-Tag–streptavidin complex reveals a novel mode of peptide recognition in which a single peptide binds simultaneously to biotin-binding pockets from adjacent subunits of streptavidin. The molecular details of peptide recognition suggest how the SBP-Tag can be further modified to become an even more useful tag for a wider range of biotechnological applications. The 38-residue SBP-Tag binds to streptavidin more tightly (K{sub d} ≃ 2.5–4.9 nM) than most if not all other known peptide sequences. Crystallographic analysis at 1.75 Å resolution shows that the SBP-Tag binds to streptavidin in an unprecedented manner by simultaneously interacting with biotin-binding pockets from two separate subunits. An N-terminal HVV peptide sequence (residues 12–14) and a C-terminal HPQ sequence (residues 31–33) form the bulk of the direct interactions between the SBP-Tag and the two biotin-binding pockets. Surprisingly, most of the peptide spanning these two sites (residues 17–28) adopts a regular α-helical structure that projects three leucine side chains into a groove formed at the interface between two streptavidin protomers. The crystal structure shows that residues 1–10 and 35–38 of the original SBP-Tag identified through in vitro selection and deletion analysis do not appear to contact streptavidin and thus may not be important for binding. A 25-residue peptide comprising residues 11–34 (SBP-Tag2) was synthesized and shown using surface plasmon resonance to bind streptavidin with very similar affinity and kinetics when compared with the SBP-Tag. The SBP-Tag2 was also added to the C-terminus of β-lactamase and was shown to be just as effective as the full-length SBP-Tag in affinity purification. These results validate the molecular structure of the SBP-Tag–streptavidin complex and establish a minimal bivalent streptavidin-binding tag from which further rational design and optimization can proceed.

  4. Structure of Dihydroorotate Dehydrogenase B: Electron Transfer between Two Flavin Groups Bridged by an Iron-Sulphur Cluster

    DEFF Research Database (Denmark)

    Rowland, Poul; Nørager, Sofie; Jensen, Kaj Frank;

    2000-01-01

    , belonging to each of the two subgroups of family 1. The B enzyme (DHODB) is a prototype for DHODs in Gram-positive bacteria that use NAD+ as the second substrate. DHODB is a heterotetramer composed of two different proteins (PyrDB and PyrK) and three different cofactors: FMN, FAD, and a [2Fe-2S] cluster....... RESULTS: Crystal structures have been determined for DHODB and its product complex. The DHODB heterotetramer is composed of two closely interacting PyrDB-PyrK dimers with the [2Fe-2S] cluster in their interface centered between the FMN and FAD groups. Conformational changes are observed between...

  5. Synthesis, Crystal Structures and Catalysis of Dinuclear Cd(Ⅱ) Complexes Bridged by Unusual (N,O,O')-Coordinated a-Amino Acids

    Institute of Scientific and Technical Information of China (English)

    DENG Dong-sheng; WANG Li; PEI Ya-mei; FENG Lu; LIU Chang-lin

    2012-01-01

    Four dinuclear amino acid cadmium(Ⅱ) complexes [Cd2(tren)2(dl-alaninato)](ClO4)3·H2O(Ⅰ),[Cd2(tren)2·(l-alaninato)](ClO4)3·H2O(Ⅱ),[Cd2(tren)2(dl-phenylalaninato)](ClO4)3(Ⅲ) and [Cd2(tren)2(l-phenylalaninato)]·(ClO4)3(Ⅳ),constructed from mixed ligands of tris(2-aminoethyl)amine(tren) and racemic or natural amino acids(amino acids=dl- or l-alanine,and dl- or l-phenylalanine),have been synthesized and characterized by X-ray crystallography.The structural analysis of complexes Ⅰ and Ⅲ reveals that the cadmium centers are coordinated by one tren ligand and one amino acid molecule with the unusual (N,O,O')-bridged mode,resulting in asymmetric chromophores of CdN4O and CdN5O in complex Ⅰ,CdN4O2 and CdN5O in complex Ⅲ,respectively.The utility of the four complexes as efficient water-compatible Lewis acid catalysts for the direct aldol reaction in water was examined.The reaction proceeded smoothly to afford the corresponding β-hydroxy ketones in up to 99% yield.Moreover,the diastereoselectivity of the reaction favors the formation of the syn-isomers.

  6. Synthesis and Crystal Structure of a Dicyanamide-bridged One-dimensional Gadolinium(Ⅲ) Complex [Gd(dca)3(phen)2(H2O)]n

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-Fang; KOU Jian-Yi; KOU Hui-Zhong; NI Zhong-Hai; CUI Ai-Li; WANG Ru-Ji

    2005-01-01

    A chainlike coordination polymer [Gd(dca)3(phen)2(H2O)]n (dca = dicyanamide,phen = 1,10-phenanthroline) has been synthesized, and its crystal structure was characterized by X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group P21/n with a = 10.6581(13), b = 15.6129(16), c = 17.733(3) (A), β = 90.499(5)°, V = 2950.8(7) (A)3, Z = 4,C30H18GdN13O, Mr = 733.82, Dc= 1.652 g/cm3, F(000) = 1444, λ(MoKα) = 0.71073 (A),μ = 2.297 mm-1, R = 0.0258 and wR = 0.0616 for 4570 observed reflections (I > 2σ(Ⅰ)). In this complex, the gadolinium atom is nine-coordinated by four dca anions, two chelated phen ligands and one H2O molecule in a distorted tricapped trigonal prism. Two bridging dca anions connect the Gd(Ⅲ) ions yielding chainlike polymers that are linked by hydrogen bonds and π-π interactions to form a three-dimensional network.

  7. Comparative Study of f-Element Electronic Structure across a Series of Multimetallic Actinide, Lanthanide-Actinide and Lanthanum-Actinide Complexes Possessing Redox-Active Bridging Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Schelter, Eric J.; Wu, Ruilian; Veauthier, Jacqueline M.; Bauer, Eric D.; Booth, Corwin H.; Thomson, Robert K.; Graves, Christopher R.; John, Kevin D.; Scott, Brian L.; Thompson, Joe D.; Morris, David E.; Kiplinger, Jaqueline L.

    2010-02-24

    A comparative examination of the electronic interactions across a series of trimetallic actinide and mixed lanthanide-actinide and lanthanum-actinide complexes is presented. Using reduced, radical terpyridyl ligands as conduits in a bridging framework to promote intramolecular metal-metal communication, studies containing structural, electrochemical, and X-ray absorption spectroscopy are presented for (C{sub 5}Me{sub 5}){sub 2}An[-N=C(Bn)(tpy-M{l_brace}C{sub 5}Me4R{r_brace}{sub 2})]{sub 2} (where An = Th{sup IV}, U{sup IV}; Bn = CH{sub 2}C{sub 6}H{sub 5}; M = La{sup III}, Sm{sup III}, Yb{sup III}, U{sup III}; R = H, Me, Et) to reveal effects dependent on the identities of the metal ions and R-groups. The electrochemical results show differences in redox energetics at the peripheral 'M' site between complexes and significant wave splitting of the metal- and ligand-based processes indicating substantial electronic interactions between multiple redox sites across the actinide-containing bridge. Most striking is the appearance of strong electronic coupling for the trimetallic Yb{sup III}-U{sup IV}-Yb{sup III}, Sm{sup III}-U{sup IV}-Sm{sup III}, and La{sup III}-U{sup IV}-La{sup III} complexes, [8]{sup -}, [9b]{sup -} and [10b]{sup -}, respectively, whose calculated comproportionation constant K{sub c} is slightly larger than that reported for the benchmark Creutz-Taube ion. X-ray absorption studies for monometallic metallocene complexes of U{sup III}, U{sup IV}, and U{sup V} reveal small but detectable energy differences in the 'white-line' feature of the uranium L{sub III}-edges consistent with these variations in nominal oxidation state. The sum of this data provides evidence of 5f/6d-orbital participation in bonding and electronic delocalization in these multimetallic f-element complexes. An improved, high-yielding synthesis of 4{prime}-cyano-2,2{prime}:6{prime},2{double_prime}-terpyridine is also reported.

  8. Designing dinuclear iron(II) spin crossover complexes. Structure and magnetism of dinitrile-, dicyanamido-, tricyanomethanide-, bipyrimidine- and tetrazine-bridged compounds.

    Science.gov (United States)

    Batten, Stuart R; Bjernemose, Jens; Jensen, Paul; Leita, Ben A; Murray, Keith S; Moubaraki, Boujemaa; Smith, Jonathan P; Toftlund, Hans

    2004-10-21

    In order to expand the few known examples of dinuclear iron(II) compounds displaying (weak) intradinuclear exchange coupling and spin-crossover on one or both of the iron(II) centres, various dinuclear compounds have been synthesised and assessed for their spin-crossover and exchange coupling behaviour. The key aim of the work was to prepare and structurally characterise 'weakly linked' and 'covalently bridged' systems incorporating bridging ligands such as alkyldinitriles (e.g.NC(CH(2))(4)CN), bipyrimidine (bpym), dicyanamide (dca(-)), tricyanomethanide (tcm(-)), 3,6-bis(2-pyridyl)tetrazine (bptz) and 3,6-bis(2-pyridyl)2,5-dihydrotetrazine (H(2)bptz). The 'end groups', which complete the Fe(ii)N(6) chromophores, include tris(2-pyridylmethyl)amine (tpa), di(2-pyridylethyl)(2-pyridylmethyl)amine (tpa'), 3-(2-pyridyl)pyrazole (pypzH), 1,10-phenanthroline (1,10-phen), tris(pyrazolyl)methane (tpm) and NCX(-)(X = S, Se). It was quite difficult to achieve the spin-crossover condition, many ligand combinations yielding high-spin/high-spin (HS-HS) Fe(II)Fe(II) spin states at all temperatures (300-2 K) with very weak antiferromagnetic coupling (J spin-crossover beginning above 300 K. 'Half crossover' examples, yielding HS-LS states below the spin transition, similar to those noted by Real and coworkers in some mu-bpym systems, were noted for [(1,10-phen)(NCS)(2)Fe(mu-bpym)Fe(NCS)(2)(1,10-phen)], 2, [(pypzH)(NCSe)(2)Fe(mu-bpym)Fe(NCSe)(2)(pypzH)], 4, and [(tpa)Fe(mu-H(2)bptz)Fe(tpa)](ClO(4))(4), 8. Interestingly, the mu-bptz analogue, 7, remained LS-LS at all temperatures with the start of a broad spin crossover evident above 300 K. No thermal hysteresis was evident in the spin transitions of these new dinuclear crossover species indicating a lack of intra- or interdinuclear cooperativity.

  9. OGLE-ing the Magellanic System: Three-dimensional structure of the Clouds and the Bridge using classical Cepheids

    CERN Document Server

    Jacyszyn-Dobrzeniecka, Anna M; Mróz, P; Skowron, J; Soszyński, I; Udalski, A; Pietrukowicz, P; Kozłowski, S; Wyrzykowski, Ł; Poleski, R; Pawlak, M; Szymański, M K; Ulaczyk, K

    2016-01-01

    We analyzed a sample of 9418 fundamental-mode and first-overtone classical Cepheids from the OGLE-IV Collection of Classical Cepheids. The distance to each Cepheid was calculated using the period-luminosity relation for the Wesenheit magnitude, fitted to our data. The classical Cepheids in the LMC are situated mainly in the bar and in the northern arm. The eastern part of the LMC is closer to us and the plane fit to the whole LMC sample yields the inclination i=24.2+-0.6 deg and position angle P.A.=151.4+-1.5 deg. We redefined the LMC bar by extending it in the western direction and found no offset from the plane of the LMC contrary to previous studies. On the other hand, we found that the northern arm is offset from a plane by about -0.5 kpc, which was not observed before. The age distribution of the LMC Cepheids shows one maximum at about 100 Myr. We demonstrate that the SMC has a non-planar structure and can be described as an extended ellipsoid. We identified two large ellipsoidal off-axis structures in t...

  10. Road Bridges and Culverts, Road Structures, Published in 2005, 1:1200 (1in=100ft) scale, Iowa Department of Transportation.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Road Bridges and Culverts dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Orthoimagery information as of 2005. It is described...

  11. Thermal bridges. Causes and impacts, information on reduction and avoidance; Waermebruecken. Ursachen und Auswirkungen, Hinweise zur Verringerung und Vermeidung

    Energy Technology Data Exchange (ETDEWEB)

    Feist, Wolfgang; Born, Rolf

    2012-11-15

    Thermal bridges increase the heat demand, affect the thermal comfort, facilitate mould cultures and cause structural damage. Many thermal bridges can be avoided by proper building construction details. At least the impact of thermal bridges can be avoided.

  12. Molecular and electronic structure of osmium complexes confined to Au(111) surfaces using a self-assembled molecular bridge

    Energy Technology Data Exchange (ETDEWEB)

    Llave, Ezequiel de la; Herrera, Santiago E.; Adam, Catherine; Méndez De Leo, Lucila P.; Calvo, Ernesto J.; Williams, Federico J., E-mail: fwilliams@qi.fcen.uba.ar [INQUIMAE-CONICET, Departamento de Química Inorgánica, Analítica y Química-Física, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Buenos Aires C1428EHA (Argentina)

    2015-11-14

    The molecular and electronic structure of Os(II) complexes covalently bonded to self-assembled monolayers (SAMs) on Au(111) surfaces was studied by means of polarization modulation infrared reflection absorption spectroscopy, photoelectron spectroscopies, scanning tunneling microscopy, scanning tunneling spectroscopy, and density functional theory calculations. Attachment of the Os complex to the SAM proceeds via an amide covalent bond with the SAM alkyl chain 40° tilted with respect to the surface normal and a total thickness of 26 Å. The highest occupied molecular orbital of the Os complex is mainly based on the Os(II) center located 2.2 eV below the Fermi edge and the LUMO molecular orbital is mainly based on the bipyridine ligands located 1.5 eV above the Fermi edge.

  13. Comprehensive photoelectron spectroscopic study of anionic clusters of anthracene and its alkyl derivatives: Electronic structures bridging molecules to bulk

    Science.gov (United States)

    Ando, Naoto; Mitsui, Masaaki; Nakajima, Atsushi

    2007-12-01

    The evolution of the electronic structure of molecular aggregates is investigated using anion photoelectron (PE) spectroscopy for anionic clusters of anthracene (Ac) and its alkyl derivatives: 1-methylanthracene (1MA), 2-methylanthracene (2MA), 9-methylanthracene (9MA), 9,10-dimethylanthracene (DMA), and 2-tert-butylanthracene (2TBA). For their monomer anions (n=1), electron affinities are confined to the range from 0.47to0.59eV and are well reproduced by density functional theory calculations, showing the isoelectronic character of these molecules. For cluster anions (n=2-100) of Ac and 2MA, two types of isomers I and II coexist over a wide size range: isomers I and II-1 (4⩽nVDEs) of isomer I in all the anionic clusters depend almost linearly on n-1/3. In contrast, the VDEs of isomers II-1 (n⩾14) and II-2 (n=40-100), appeared only in Ac and 2MA cluster anions, remain constant with n and are ˜0.5eV lower than those of isomer I. The PE spectra revealed the characteristics of each isomer: isomer I possesses a monomeric anion core that is gradually embedded into the interior of the cluster with increasing n. On the other hand, isomers II-1 and II-2 possess a multimeric (perhaps tetrameric) anion core, but they differ in the number of layers from which they are made up; monolayer (isomer II-1) and multilayers (isomer II-2) of a two-dimensionally ordered, finite herringbone-type structure, in which electron attachment produces only little geometrical rearrangement. Moreover, the agreement of the constant VDEs of isomer II-2 with the bulk data demonstrates the largely localized nature of the electronic polarization around the excess charge in a crystal-like environment, where about 50molecules provide a charge stabilization energy comparable to the bulk.

  14. Substituent effects of N4 Schiff base ligands on the formation of fluoride-bridged dicobalt(ii) complexes via B-F abstraction: structures and magnetism.

    Science.gov (United States)

    Cho, Yae In; Ward, Meredith L; Rose, Michael J

    2016-09-14

    We report the synthesis of two fluoride bridged cobalt(ii) dimers - [Co(μ-F)(pnN4-PhCl)2(OH2)(MeCN)](BF4)3 (1) and [Co(μ-F)2(pnN4-PhCl)2](BF4)2 (2) - and related complexes derived from propyl-bridged N4 Schiff base plus pyridine ligands. Notably, the bridging fluoride ion(s) emanate from B-F abstraction processes on the BF4 anions in the starting salt, [Co(H2O)6](BF4)2. Two types of bridging motifs are generated - mono-bridged (μ-F) or di-bridged (μ-F)2- synthetically differentiated by the absence or presence of pyridine, respectively, during metalation. The synergistic roles of pyridine and the (ClPh)N4 ligand in promoting B-F abstraction were clarified by the isolation and crystallization of the simple tetrakis-pyridine monomeric complex [Co(py)4(MeCN)2](BF4)2 (4) [no B-F abstraction]; subsequent addition of the (ClPh)N4 ligand to 4 resulted in formation of the dimeric, di-bridged complex 2. Omission of pyridine during metalation resulted in formation of the mono-bridged dimer 1. The bulky chlorophenyl substituents were obligate for B-F abstraction, as metalation of the unsubstituted N4 ligand resulted in the non-fluoride-bridged dimer, [Co(pnN4)3](BF4)4 (3). In magnetic studies, complexes 1 (μeff = 6.24μB, 298 K) and 2 (μeff = 7.70μB, 298 K) both exhibit antiferromagnetic (AFM) coupling, but to different extents. Temperature-dependent magnetic susceptibility measurements (SQUID, 2 → 300 K) reveal that the linearity of the mono-fluoride bridge in 1 [∠Co-F-Co = 159.47(11)°] results in very strong AFM coupling (J = -14.9 cm(-1)). In contrast, the more acute Co2F2 diamond core [∠Co-F-Co = 98.8(2)°, 99.1(2)°] results in a smaller extent of AFM coupling (J = -2.97 cm(-1)). Overall, the results indicate the 'non-innocence' of the BF4 counterion in cobalt(ii) chemistry, and dimers 1 and 2 affirm the effect of the geometry of the bridging fluoride ion(s) in determining the extent of AFM coupling.

  15. Implementation of Bridge Management System on Interurban Bridge in Maluku Province

    Directory of Open Access Journals (Sweden)

    Erwin Marasabessy

    2015-05-01

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

  16. Analysis of the Influence of Organic Corrosion Inhibitors on Corrosion of Reinforcement in Concrete Bridge Structure Under Simulated Field Service Environment

    OpenAIRE

    Shi, Liang; Ye, J.; C. C. CHEN; Wu, Y; Liu, J. Z.

    2014-01-01

    For concrete bridge projects in marine environments, attention must be paid to the reinforcement corrosion problems caused by chloride intrusion. As kinds of functional admixtures, which can reduce the reinforcement corrosion rate, corrosion inhibitors are becoming very popular in China in new bridge projects. Corrosion inhibitors cover both inorganic and organic inhibitors. Nitrite is representative of inorganic corrosion inhibitors, but its carcinogenicity has hindered its further developme...

  17. Heterobimetallic oxalato-bridged M(II)Re(IV) complexes (M = Mn, Fe, Co, Ni): synthesis, crystal structure, and magnetic properties.

    Science.gov (United States)

    Chiozzone, Raúl; González, Ricardo; Kremer, Carlos; De Munno, Giovanni; Armentano, Donatella; Lloret, Francesc; Julve, Miguel; Faus, Juan

    2003-02-24

    Four rhenium(IV)-M(II) bimetallic complexes of formula [ReCl(4)(mu-ox)M(dmphen)(2)].CH(3)CN with M = Mn (1), Fe (2), Co (3), and Ni (4) (ox = oxalate anion, dmphen = 2,9-dimethyl-1,10-phenanthroline) have been synthesized and the crystal structures of 1 and 3 determined by single-crystal X-ray diffraction. 1 and 3 are isostructural and crystallize in the monoclinic system, space group P2(1)/c, with a = 16.008(4) A, b = 12.729(2) A, c = 18.909(5) A, beta = 112.70(2) degrees, and Z = 4 for 1 and a = 15.998(4) A, b = 12.665(2) A, c = 18.693(5) A, beta = 112.33(2) degrees, and Z = 4, for 3. The structure of 1 and 3 is made up of neutral [ReCl(4)(mu-ox)M(dmphen)(2)] bimetallic units (M = Mn (1), Co (3)) and acetonitrile molecules of crystallization. M(II) and Re(IV) metal ions exhibit distorted octahedral coordination geometries being bridged by a bis(bidentate) oxalato ligand. The magnetic behavior of 1-4 has been investigated over the temperature range 2.0-300 K. A very weak antiferromagnetic coupling between Re(IV) and Mn(II) occurs in 1 (J = -0.1 cm(-)(1)), whereas a significant ferromagnetic interaction between Re(IV) and M(II) is observed in 2-4 [J = +2.8 (2), +5.2 (3), and +5.9 cm(-)(1) (4)].

  18. Bridging gaps: On the performance of airborne LiDAR to model wood mouse-habitat structure relationships in pine forests.

    Science.gov (United States)

    Jaime-González, Carlos; Acebes, Pablo; Mateos, Ana; Mezquida, Eduardo T

    2017-01-01

    LiDAR technology has firmly contributed to strengthen the knowledge of habitat structure-wildlife relationships, though there is an evident bias towards flying vertebrates. To bridge this gap, we investigated and compared the performance of LiDAR and field data to model habitat preferences of wood mouse (Apodemus sylvaticus) in a Mediterranean high mountain pine forest (Pinus sylvestris). We recorded nine field and 13 LiDAR variables that were summarized by means of Principal Component Analyses (PCA). We then analyzed wood mouse's habitat preferences using three different models based on: (i) field PCs predictors, (ii) LiDAR PCs predictors; and (iii) both set of predictors in a combined model, including a variance partitioning analysis. Elevation was also included as a predictor in the three models. Our results indicate that LiDAR derived variables were better predictors than field-based variables. The model combining both data sets slightly improved the predictive power of the model. Field derived variables indicated that wood mouse was positively influenced by the gradient of increasing shrub cover and negatively affected by elevation. Regarding LiDAR data, two LiDAR PCs, i.e. gradients in canopy openness and complexity in forest vertical structure positively influenced wood mouse, although elevation interacted negatively with the complexity in vertical structure, indicating wood mouse's preferences for plots with lower elevations but with complex forest vertical structure. The combined model was similar to the LiDAR-based model and included the gradient of shrub cover measured in the field. Variance partitioning showed that LiDAR-based variables, together with elevation, were the most important predictors and that part of the variation explained by shrub cover was shared. LiDAR derived variables were good surrogates of environmental characteristics explaining habitat preferences by the wood mouse. Our LiDAR metrics represented structural features of the forest

  19. 基于荷载试验数据修正桥梁结构有限元计算模型的研究%Study of bridge structure FEM updating based on load test experimental data

    Institute of Scientific and Technical Information of China (English)

    张征文; 李永庆

    2014-01-01

    以浙江省长兴县上莘大桥为对象,采用一般方法建立桥梁分析的初始有限元计算模型,根据桥梁交工验收荷载试验采集的静、动载试验数据,通过建立考虑变形、频率及振型等静、动力信息的多目标函数对初始有限元模型进行修正,得到能够反映桥梁结构真实状况的基准有限元模型。修正后基准有限元模型计算结果与不同静载试验工况下实测数值、动载试验工况下实测振动频率、模态等响应结果进行了对比,结果表明:利用桥梁荷载试验实测数据对桥梁有限元计算模型修正后,有限元计算模型计算结果与荷载试验实测响应结果均能保持一致,利用荷载试验数据修正桥梁结构有限元计算模型是可行的。%With the Shangshen Bridge in Zhejiang province as an example,an initial finite element model is established(developed) under the bridge design drawings,According to the bridge Completion Acceptance of load test collected static and dynamic load test data were collected, considering the deformation, frequency and mode shapes static and dynamic information through the establishment of multi-objective function of the initial finite element model of the amendment, the reference finite element model to reflect the true state of the bridge structure. Amended Baseline Finite Element Model calculations with different static load test conditions, the measured value, measured vibration frequency of the dynamic load test conditions, And the modal response results were compared. The results showed that: the use of bridge load test measured data is limited to the bridge element calculation model correction and the finite element model calculations and load test measured response results are consistent. The load test data correction of bridge structure with finite element model is feasible.

  20. 桥梁管理系统与结构健康监测系统的信息融合%The information fusion of bridge management system and structural health monitoring system

    Institute of Scientific and Technical Information of China (English)

    常军

    2012-01-01

    通过对桥梁管理系统与结构健康监测系统的应用现状分析,发现两大系统没有进行良好地融合,各自独立,造成资源浪费、所获得的结果不全面等问题。论文基于对两系统的特点及应用情况研究,进而对两种系统融合的必要性和可行性进行了分析。最后,通过对桥梁管理系统中的主要模块之一——状态评估中两系统如何进行信息融合,给出了两系统融合的具体做法。信息融合后的桥梁管理系统可以得出更加实际的桥梁状态评估结果及桥梁的剩余寿命预测结果,进而为桥梁管理的决策者制定出更加实际有效的桥梁维护策略提供依据。%Through the application status investigation of the bridge management system and the structural health monitoring system, it was found that the two systems were not fused well, which resulted in resources waste and inaccurate outcomes. Based on the research of status and application of the two systems, the paper analyzed the necessity and feasibility of the information fusion of the two systems. Finally, the specific information fusion of the two systems is presented through the exact information fusion of the systems in the bridge structural condition assessment, one of the most important modules of the bridge management system. More accurate results of the condition assessment and remaining life prediction of bridges can be obtained by the bridge management system after the fusion, which will offer some evidence for the bridge maintenance strategy made by bridge management decision-makers.

  1. Analysis of the Natural Vibration Characteristics of the Upper and Lower Structure of Arch Bridge Based on MIDAS/CIVIL%基于MIDAS/CIVIL的拱桥上下部结构自振特性分析

    Institute of Scientific and Technical Information of China (English)

    汪玉容; 岑晓倩

    2016-01-01

    On the spandrel arch bridge has the advantages of reasonable economy,beautiful appear-ance,is a bridge in the mountainous area of our country is widely used. In this paper,the MIDAS/CIVIL finite element software is used to establish the spatial dynamic model of the upper and lower structures of the upper and lower arch bridges,and the natural vibration characteristics are analyzed. By calculating the natural frequency and the vibration mode analysis,it shows that the dynamic per-formance of the upper and lower part of the existing arch bridge is satisfied.%上承式空腹式拱桥具有经济合理、造型美观等优点,是我国山区使用很广的一种桥型。运用MIDAS/CIVIL有限元软件建立既有上承式空腹式拱桥上下部结构整体的空间动力模型,并对其自振特性进行分析。通过计算自振频率及对振型的分析,表明既有上承式空腹式拱桥上下部整体的动力性能满足要求。

  2. Blue-emitting platinum(II) complexes bearing both pyridylpyrazolate chelate and bridging pyrazolate ligands: synthesis, structures, and photophysical properties.

    Science.gov (United States)

    Chang, Sheng-Yuan; Chen, Jing-Lin; Chi, Yun; Cheng, Yi-Ming; Lee, Gene-Hsiang; Jiang, Chang-Ming; Chou, Pi-Tai

    2007-12-24

    A new Pt(II) dichloride complex [Pt(fppzH)Cl2] (1), in which fppzH = 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole, was prepared by the treatment of a pyridylpyrazole chelate fppzH with K2PtCl4 in aqueous HCl solution. Complex 1 could further react with its parent pyrazole (pzH), 3,5-dimethylpyrazole (dmpzH), or 3,5-di-tert-butylpyrazole (dbpzH) to afford the monometallic [Pt(fppz)(pzH)Cl] (2), [Pt(fppz)(dmpzH)Cl] (3), [Pt(fppz)(dmpzH)2]Cl (4), or two structural isomers with formula [Pt(fppz)(dbpzH)Cl] (5a,b). Single-crystal X-ray diffraction studies of 2, 4, and 5a,b revealed a square planar Pt(II) framework, among which a strong interligand hydrogen bonding occurred between fppz and pzH ligands in 2. This interligand H-bonding is replaced by dual N-H...Cl interaction in 4 and both intermolecular N-H...O (with THF solvate) and N-H...Cl interaction in 5a,b, respectively; the latter are attributed to the bulky tert-butyl substituents that force the dbpzH ligand to adopt the perpendicular arrangement. Furthermore, complex 2 underwent rapid deprotonation in basic media to afford two isomeric complexes with formula [Pt(fppz)(mu-pz)]2 (6a,b), which are related to each other according to the spatial orientation of the fppz chelates, i.e., trans- and cis-isomerism. Similar reaction exerted on 3 afforded isomers 7a,b. Both 6a,b (7a,b) are essentially nonemissive in room-temperature fluid state but afford strong blue phosphorescence in solid state prepared via either vacuum-deposited thin film or 77 K CH2Cl2 matrix. As also supported by the computational approaches, the nature of emission has been assigned to be ligand-centered triplet pipi* mixed with certain metal-to-ligand charge-transfer character.

  3. Proceedings of the International Workshop on Structural Analyses Bridging over between Amorphous and Crystalline Materials (SABAC2008); January 10-11, 2008, Tokai-mura, Naka-gun, Ibaraki-ken, Japan, Techno Community Square "RICOTTI"

    OpenAIRE

    社本 真一; 樹神 克明

    2008-01-01

    International workshop entitled "Structural Analyses Bridging over between Amorphous and Crystalline Materials" (SABAC2008) was held on January 10 and 11, 2007 at Techno Community Square "RICOTTI" in Tokai. Amorphous and crystalline materials are studied historically by various approaches. Recent industrial functional materials such as optical memory material, thermoelectric material, hydrogen storage material, and ionic conductor have intrinsic atomic disorders in their lattices. These local...

  4. Structural differences between the avian and human H7N9 hemagglutinin proteins are attributable to modifications in salt bridge formation: a computational study with implications in viral evolution.

    Directory of Open Access Journals (Sweden)

    Marni E Cueno

    Full Text Available Influenza A hemagglutinin (HA is a homotrimeric glycoprotein composed of a fibrous globular stem supporting a globular head containing three sialic acid binding sites responsible for infection. The H7N9 strain has consistently infected an avian host, however, the novel 2013 strain is now capable of infecting a human host which would imply that the HA in both strains structurally differ. A better understanding of the structural differences between the avian and human H7N9 strains may shed light into viral evolution and transmissibility. In this study, we elucidated the structural differences between the avian and human H7N9 strains. Throughout the study, we generated HA homology models, verified the quality of each model, superimposed HA homology models to determine structural differences, and, likewise, elucidated the probable cause for these structural differences. We detected two different types of structural differences between the novel H7N9 human and representative avian strains, wherein, one type (Pattern-1 showed three non-overlapping regions while the other type (Pattern-2 showed only one non-overlapping region. In addition, we found that superimposed HA homology models exhibiting Pattern-1 contain three non-overlapping regions designated as: Region-1 (S1571-A1601; Region-3 (R2621-S2651; and Region-4 (S2701-D2811, whereas, superimposed HA homology models showing Pattern-2 only contain one non-overlapping region designated as Region-2 (S1371-S1451. We attributed the two patterns we observed to either the presence of salt bridges involving the E1141 residue or absence of the R1411:D771 salt bridge. Interestingly, comparison between the human H7N7 and H7N9 HA homology models showed high structural similarity. We propose that the putative absence of the R1411:D771 salt bridge coupled with the putative presence of the E1141:R2621 and E1141:K2641 salt bridges found in the 2013 H7N9 HA homology model is associated to human-type receptor binding

  5. Synthesis, crystal structures and magnetic properties of cyanide- and phenolate-bridged [M(III)NiII]2 tetranuclear complexes (M=Fe and Cr).

    Science.gov (United States)

    Toma, Liviu; Toma, Luminita Marilena; Lescouëzec, Rodrigue; Armentano, Donatella; De Munno, Giovanni; Andruh, Marius; Cano, Joan; Lloret, Francesc; Julve, Miguel

    2005-04-21

    The binuclear complex NiII2L(H2O)2(ClO4)2(1) and the neutral tetranuclear bimetallic compounds [{M(III)(phen)(CN)4}2{NiII2L(H2O)2}].2CH3CN with M=Fe (2) and Cr (3)[H2L=11,23-dimethyl-3,7,15,19-tetraazatricyclo[19.3.1.1(9,13)]hexacosa-2,7,9,11,13(26),14,19,21(25),22,24-decaene-25,26-diol] have been synthesized and the structures of and determined by single crystal X-ray diffraction. and are isostructural compounds whose structure is made up of centrosymmetric binuclear cations [Ni2(L)(H2O)2]2+ and two peripheral [M(phen)(CN)4]- anions [M=Fe (2) and Cr (3)] acting as monodentate ligands towards the nickel atoms through one of their four cyanide nitrogen atoms. The environment of the metal atoms in 2 and 3 is six-coordinated: two phen-nitrogen and four cyanide-carbon atoms at the iron and chromium atoms and a water molecule, one cyanide-nitrogen and two phenolate-oxygens and two imine-nitrogens from the binucleating ligand L2- at the nickel atom build distorted octahedral surroundings. The values of the FeNi and CrNi separations through the single cyanide bridge are 5.058(1) and 5.174(2)A respectively, whereas the Ni-Ni distances across the double phenolate bridge are 3.098(2)(2) and 3.101(1) A (3). The magnetic properties of have been investigated in the temperature range 1.9-290 K. The magnetic behaviour of corresponds to that of an antiferromagnetically coupled nickel(II) dimer with J=-61.0(1) cm-1, the Hamiltonian being defined as H=-J S(A).S(B). An overall antiferromagnetic behaviour is observed for and with a low-lying singlet spin state. The values of the intramolecular magnetic couplings are J(Fe-Ni)=+17.4(1) cm-1 and J(Ni-Ni(a))=-44.4(1) cm-1 for and J(Cr-Ni)=+11.8(1) cm-1 and J(Ni-Ni(a))=-44.6(1) cm-1 for [H=-J(M-Ni)(S(M).S(Ni)+S(Ma).S(Nia))-J(Ni-Nia)S(Ni)S(Nia)]. Theoretical calculations using methods based on density functional theory (DFT) have been employed on in order to analyze the efficiency of the exchange pathways involved and also to substantiate

  6. Aluminum Complexes Stabilized by Piperazidine-Bridged Bis(phenolate) Ligands: Syntheses, Structures, and Applica- tion in the Ring-Opening Polymerization of ε-Caprolactone

    Institute of Scientific and Technical Information of China (English)

    李文艺; 姚英明; 张勇; 沈琪

    2012-01-01

    The synthesis and characterization of aluminum alkoxide and alkyl complexes stabilized by piperazidine- bridged bis(phenolate) ligands are described. Treatment of ligand precursors Hz[ONNO]^1 {Hz[ONNO]^1= 1,4-bis(2-hydroxy-3-tert-butyl-5-methylbenzyl)piperazidine} and Hz[ONNO]2 {H2[ONNO]2=1,4-bis(2-hydroxy3,5-di-tert-butylbenzyl)piperazidine} with A1Et2(OCH2Ph) and A1Etz(OPr-i), which were generated in situ by the reactions of AIEt3 with equivalent of the corresponding alcohols, in a 1: 1 molar ratio in THF gave the corresponding aluminum alkoxide complexes [ONNO]IAI(OCH2Ph) (1) and [ONNO]2Al(OPr-i) (2), respectively. The reaction of H2[ONNO]^1 with A1Etz(OCHzPh) in a 1 : 2 molar ratio in THF afforded a mixture of monometallic aluminum ethyl complex [ONNO] 1A1Et (3) and complex 1, which can be isolated by stepwise crystallization. Similarly, Hz[ONNO]2 reacted with A1Etz(OPr-0 in a 1: 2 molar ratio in THF to give a mixture of aluminum ethyl complex [ONNO]2AlEt (4) and complex 2. Complexes 1 and 2 were also available via treatment of complexes 3 and 4 with 1 equiv, of benzyl alcohol and isopropyl alcohol, respectively. All of these complexes were fully characterized including X-ray structural determination. It was found that complexes 1 to 4 can initiate the ring-opening polymerization of e-caprolactone, and complexes 1 and 2 showed higher catalytic activity in comparison with com- plexes 3 and 4.

  7. I-5/Gilman advanced technology bridge project

    Science.gov (United States)

    Lanza di Scalea, Francesco; Karbhari, Vistasp M.; Seible, Frieder

    2000-04-01

    The UCSD led I-5/Gilman Advanced Technology Bridge Project will design and construct a fully functional traffic bridge of advanced composite materials across Interstate 5 in La Jolla, California. Its objective is to demonstrate the use of advanced composite technologies developed by the aerospace industry in commercial applications to increase the life expectancy of new structures and for the rehabilitation of aging infrastructure components. The structure will be a 450 ft long, 60 ft wide cable-stayed bridge supported by a 150 ft A-frame pylon with two vehicular lanes, two bicycle lanes, pedestrian walkways and utility tunnels. The longitudinal girders and pylon will be carbon fiber shells filled with concrete. The transverse deck system will consist of hollow glass/carbon hybrid tubes and a polypropylene fiber reinforced concrete deck with an arch action. Selected cables will be composite. The bridge's structural behavior will be monitored to determine how advanced composite materials perform in civil infrastructure applications. The bridge will be instrumented to obtain performance and structural health data in real time and, where possible, in a remote fashion. The sensors applied to the bridge will include electrical resistance strain gages, fiberoptic Bragg gratings and accelerometers.

  8. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

    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.

  9. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

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

  10. Bridging the Gap

    DEFF Research Database (Denmark)

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

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

  11. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  12. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  13. Parabolic metamaterials and Dirac bridges

    Science.gov (United States)

    Colquitt, D. J.; Movchan, N. V.; Movchan, A. B.

    2016-10-01

    A new class of multi-scale structures, referred to as `parabolic metamaterials' is introduced and studied in this paper. For an elastic two-dimensional triangular lattice, we identify dynamic regimes, which corresponds to so-called `Dirac Bridges' on the dispersion surfaces. Such regimes lead to a highly localised and focussed unidirectional beam when the lattice is excited. We also show that the flexural rigidities of elastic ligaments are essential in establishing the `parabolic metamaterial' regimes.

  14. Syntheses, Crystal Structures and Fluorescence of Cadmium(Ⅱ) Coordination Polymers with Pyrazine-1,4-dioxide, 2-Methylpyrazine-1,4-dioxide and Thiocyanate as Mixed Bridge Ligands

    Institute of Scientific and Technical Information of China (English)

    SHI Jing-Min; ZHANG Feng-Xia; ZHANG Xia; XU Hai-Yan; LIU Lian-Dong; MA Jian-Ping

    2006-01-01

    Two Cd(Ⅱ) coordination polymers have been synthesized with pyrazine-1,4-dioxide(L1), 2-methylpyrazine-1,4-dioxide (L2), and thiocyanate anion as mixed bridge ligands. Crystal data for complex 1 [Cd(μ13-SCN-)2(L1)]n: monoclinic system, space group P21/n with a =6.8342(11), b = 14.349(2), c = 10.5443(16) (A), β = 98.534(2)°, V = 1022.5(3) (A)3, Z = 4,C6H4CdN4O2S2, Mr = 340.65, Dc. = 2.213 g/cm3, F(000) = 656 andμ = 2.527 mm-1; and those for2: triclinic system, space group P1 with a = 7.877(3), b = 8.693(3), c = 8.754(3) (A), α =102.297(6), β= 102.464(6), γ= 98.480(6)°, V = 560.0(3) (A)3, Z = 2, C7H6CdN4O2S2, Mr = 354.68,Dc = 2.103 g/cm3, F(000) = 344 and μ = 2.311 mm-1. 1 shows a three-dimensional network structure, and along the c direction a one-dimensional chain is constructed by the coordination of Cd(Ⅱ) ions withμ1,3-SCN- ligands, and the L1 bridging ligands made the chains connect each other leading to the formation of a three-dimensional structure. For 2, the one-dimensional chains along the b axis are generated by the coordination of L2 bridging ligands with Cd(Ⅱ) ions, and the chains are further joined byμ1,3-SCN- bridging ligands forming a two-dimensional sheet structure on the (1 0 -1) plane. Both complexes 1 and 2 exhibit strong fluorescence emission.

  15. Practical Approach to Fragility Analysis of Bridges

    Directory of Open Access Journals (Sweden)

    Yasamin Rafie Nazari

    2012-12-01

    Full Text Available Damages during past earthquakes reveal seismic vulnerability of bridge structures and the necessity of probabilistic approach toward seismic performance evaluation of bridges and its interpretation in terms of decision variables such as repair cost, downtime and life loss. This Procedure involves hazard analysis, structural analysis, damage analysis and loss analysis. The purpose of present study is reviewing different methods developed to derive fragility curves for damage analysis of bridges and demonstrating a simple procedure for fragility analysis using Microsoft Office Excel worksheet to reach probability of occurring predefined level of damage due to different levels of seismic demand parameters. The input of this procedure is the intensity of ground motion and the output is an appropriate estimate of the expected damage. Different observed damages of the bridges are discussed and compared the practical definition of damage states. Different methods of fragility analyses are discussed and a practical step by step example is illustrated.

  16. Monitoring system of arch bridge for safety network management

    Science.gov (United States)

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

    2010-03-01

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

  17. Application of Microtremor Measurement Techniques to Detection of Structural Damage of an Ancient Arch Bridge%微动测试技术在古建筑拱桥结构检测中的应用①微动测试技术在古建筑拱桥结构检测中的应用

    Institute of Scientific and Technical Information of China (English)

    范岩旻; 车爱兰; 陈峰; 曹永康

    2015-01-01

    在古桥梁建筑结构保护中,无损高精度检测一直是一个重要的研究课题。为识别古桥梁拱桥的结构损伤问题,以上海青浦迎祥桥为研究对象,采用全站仪对桥梁结构的变形进行观测及分析,评价桥梁的变形及受力状态;采用微动测试技术,获取结构的损伤动力特性参数,包括固有频率及振动模态。通过分析现有桥梁的模态分布,观测振动模态的突变位置确定结构损伤位置,比较结构的变形特性,对结构的损伤程度进行评价。%There are vast territorial and crisscrossing rivers in China.During thousands of years,the Chinese people have built hundreds of thousands of bridges.With diverse structures composed of various materials,these bridges,which are treasures of Chinese architecture,represent,to some extent,the history of Chinese culture.These ancient bridges,though witnessing extreme weather, have been,and are being,damaged due to construction limitations,long time of loading,and the continuous dynamics of erosion and other natural and human factors.Given this situation,it is critical to protect these ancient bridges with detection technology that does not damage the bridg-es.For the protection of ancient bridge structures,high precision detection technology that does not damage the detected targets has been an important research topic.To identify damages to ancient bridges with arch-bridge structures,the Shanghai Yingxiang Bridge in the Qingpu District is analyzed in this study.The structural features are analyzed and the deformed part of the struc-ture is determined with the help of a total station device to evaluate the deformation and stress states of the bridge.Furthermore,with the application of micro-motion testing technology,the dynamic characteristic parameter of the structural damage,which includes the intrinsic frequency and vibration mode,is determined.After the analysis of the mode distribution of existing bridges and

  18. Structural analysis and evaluation of actual PC bridge using 950 keV/3.95 MeV X-band linacs

    Science.gov (United States)

    Takeuchi, H.; Yano, R.; Ozawa, I.; Mitsuya, Y.; Dobashi, K.; Uesaka, M.; Kusano, J.; Oshima, Y.; Ishida, M.

    2017-07-01

    In Japan, bridges constructed during the strong economic growth era are facing an aging problem and advanced maintenance methods have become strongly required recently. To meet this demand, we develop the on-site inspection system using 950 keV/3.95 MeV X-band (9.3 GHz) linac X-ray sources. These systems can visualize in seconds the inner states of bridges, including cracks of concrete, location and state of tendons (wires) and other imperfections. At the on-site inspections, 950 keV linac exhibited sufficient performance. But, for thicker concrete, it is difficult to visualize the internal state by 950 keV linac. Therefore, we proceeded the installation of 3.95 MeV linac for on-site bridge inspection. In addition, for accurate evaluation, verification on the parallel motion CT technique and FEM analysis are in progress.

  19. Damage Detection of a Continuous Bridge from Response of a Moving Vehicle

    Directory of Open Access Journals (Sweden)

    Z. H. Li

    2014-01-01

    Full Text Available This paper presents a multistage multipass method to identify the damage location of a continuous bridge from the response of a vehicle moving on the rough road surface of the bridge. The vehicle runs over the bridge several times at different velocities and the corresponding responses of the vehicle can be obtained. The vertical accelerations of the vehicle running on the intact and damaged bridges are used for identification. The multistage damage detection method is implemented by the modal strain energy based method and genetic algorithm. The modal strain energy based method estimates the damage location by calculating a damage indicator from the frequencies extracted from the vehicle responses of both the intact and damaged states of the bridge. At the second stage, the identification problem is transformed into a global optimization problem and is solved by genetic algorithm techniques. For each pass of the vehicle, the method can identify the location of the damage until it is determined with acceptable accuracy. A two-span continuous bridge is used to verify the method. The numerical results show that this method can identify the location of damage reasonably well.

  20. Synthesis, structural characterization and antimicrobial activities of diorganotin(IV) complexes with azo-imino carboxylic acid ligand: Crystal structure and topological study of a doubly phenoxide-bridged dimeric dimethyltin(IV) complex appended with free carboxylic acid groups

    Science.gov (United States)

    Roy, Manojit; Roy, Subhadip; Devi, N. Manglembi; Singh, Ch. Brajakishor; Singh, Keisham Surjit

    2016-09-01

    Diorganotin(IV) complexes appended with free carboxylic acids were synthesized by reacting diorganotin(IV) dichlorides [R2SnCl2; R = Me (1), Bu (2) and Ph (3)] with an azo-imino carboxylic acid ligand i.e. 2-{4-hydroxy-3-[(2-hydroxyphenylimino)methyl]phenylazo}benzoic acid in presence of triethylamine. The complexes were characterized by elemental analysis, IR and multinuclear NMR (1H, 13C and 119Sn) spectroscopy. The structure of 1 in solid state has been determined by X-ray crystallography. Crystal structure of 1 reveals that the compound crystallizes in monoclinic space group P21/c and is a dimeric dimethyltin(IV) complex appended with free carboxylic acid groups. In the structure of 1, the Sn(IV) atoms are hexacoordinated and have a distorted octahedral coordination geometry in which two phenoxy oxygen atoms and the azomethine nitrogen atom of the ligand coordinate to each tin atom. One of the phenoxy oxygen atom bridges the two tin centers resulting in a planar Sn2O2 core. Topological analysis is used for the description of molecular packing in 1. Tin NMR spectroscopy study indicates that the complexes have five coordinate geometry around tin atom in solution state. Since the complexes have free carboxylic acids, these compounds could be further used as potential metallo-ligands for the synthesis of other complexes. The synthesized diorganotin(IV) complexes were also screened for their antimicrobial activities and compound 2 showed effective antimicrobial activities.

  1. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex[La(DMSO)3(H2O)3Cr(CN)6]·H2O (DMSO = Dimethylsulfoxide) with One-dimensional Chain Molecular Structure

    Institute of Scientific and Technical Information of China (English)

    梁淑惠; 车云霞; 郑吉民

    2004-01-01

    The title complex [La(DMSO)3(H2O)3Cr(CN)6](H2O was obtained by the reaction of LaCl3(7H2O, DMSO and K3[Cr(CN)6] in aqueous solution on a hot water bath. The crystal crystallizes in orthorhombic, space group P212121 with a = 9.827(3), b = 15.037(4), c = 17.633(5)A, C12H26CrLaN6O7S3, Mr = 653.48, Z = 4, V = 2605.7(13) A3, Dc = 1.666 g/m3, μ (MoKα) = 2.314 mm-1, F(000) = 1300, R = 0.0205 and wR = 0.0481 for 5038 observed reflections (I > 2σ(I)). La3+ ion is eight-coordinated by three DMSO molecules, three H2O molecules and two [Cr(CN)6]3- units. The structure of the title complex possesses a cyano-bridged onedimensional zigzag chain structure with alternating La(DMSO)3(H2O)3 and Cr(CN)6 moieties, which are linked by some hydrogen bonds to form a 3D network structure.

  2. Syntheses and structures of zirconium(IV) complexes supported by 2,6-di-adamantylaryloxide ligands and formation of arene-bridged dizirconium complexes with an inverse sandwich structure.

    Science.gov (United States)

    Watanabe, Takahito; Ishida, Yutaka; Matsuo, Tsukasa; Kawaguchi, Hiroyuki

    2010-01-14

    The reaction of 2,6-di-adamantyl-4-R-phenol (Ar(R)OH, R = Me, tBu) with nBuLi in THF gave good yields of the lithiated derivatives (Ar(R)O)Li(THF)2. Addition of 2 equiv. of (ArRO)Li(THF)2 to ZrCl4(THF)2 in THF afforded the base-free dichloride complexes (Ar(R)O)ZrCl2 (R = Me 1a, tBu 1b). The dibenzyl derivative (Ar(Me)O)2Zr(CH2Ph)2 2 was synthesized by addition of 2 equiv. of PhCH2MgCl to 1a in toluene. Reduction of the dichloride complexes 1a and 1b with KC8 in toluene led to the formation of the toluene-bridged dizirconium complexes [(Ar(R)O)2Zr]2(-6:6-C7H8) (R = Me 3a, tBu 3b). A similar reaction was carried out in benzene to produce the corresponding benzene-bridged analogue [(Ar(R)O)2Zr]2(mu-eta(6):eta(6)-C6H6) (R = Me 4a, tBu 4b). Treatment of 3a with 2 equiv. of 1-azidoadamantane (AdN3) in THF resulted in the release of toluene and N2, generating the monomeric imide complex (Ar(Me)O)2Zr(NAd)(thf) 5. When the analogous reaction was carried out in toluene, (Ar(Me)O)2Zr(AdNN=NNAd) 6 was obtained. Structures of (Ar(R)O)Li(THF)2, 1a, 2 and 5 were determined by X-ray crystallography.

  3. Crystal structure and spectroscopic analysis of a new oxalate-bridged MnII compound: catena-poly[guanidinium [[aquachloridomanganese(II]-μ2-oxalato-κ4O1,O2:O1′,O2′] monohydrate

    Directory of Open Access Journals (Sweden)

    Hiba Sehimi

    2016-05-01

    Full Text Available As part of our studies on the synthesis and the characterization of oxalate-bridged compounds M–ox–M (ox = oxalate dianion and M = transition metal ion, we report the crystal structure of a new oxalate-bridged MnII phase, {(CH6N3[Mn(C2O4Cl(H2O]·H2O}n. In the compound, a succession of MnII ions (situated on inversion centers adopting a distorted octahedral coordination and bridged by oxalate ligands forms parallel zigzag chains running along the c axis. These chains are interconnected through O—H...O hydrogen-bonding interactions to form anionic layers parallel to (010. Individual layers are held together via strong hydrogen bonds involving the guanidinium cations (N—H...O and N—H...Cl and the disordered non-coordinating water molecule (O—H...O and O—H...Cl, as well as by guanidinium π–π stacking. The structural data were confirmed by IR and UV–Visible spectroscopic analysis.

  4. 桥梁结构监测数据预处理方法及其应用%Research on Method of Data Preprocessing and Its Application for Bridge Structural Monitoring

    Institute of Scientific and Technical Information of China (English)

    雷旺龙; 孙洪鑫; 郭雪涛

    2012-01-01

    介绍了桥梁结构监测数据预处理的几种方法,并基于九江大桥健康监测系统,对系统采集的数据首先选用其中的两种数据预处理方法,分别判别数据中的异常值,剔除粗大误差,其次采用数据平滑方法对噪声数据进行处理,采取这些合理的数据预处理方法最终可以获得对桥梁结构健康状态评估起重要作用的有效数据.%This paper introduces several methods of monitoring data preprocessing for the bridge structure. Based on Jiujiang Bridge health monitoring system, firstly, choose two kinds of data preprocessing methods from the data collected by the system are chosen; abnormal data is discriminated respectively and the bulky error is eliminated. Then the noise data is processed by the smoothing method. Finally, these reasonable data preprocessing methods are used to get the effective data which plays an important role in the bridge structure health condition assessment.

  5. Sustainable Bridge Infrastructure Procurement

    DEFF Research Database (Denmark)

    Safi, Mohammed; Du, Guangli; Simonsson, Peter

    2016-01-01

    The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use...

  6. Bridge the Gap

    DEFF Research Database (Denmark)

    Marselis, Randi Lorenz

    2017-01-01

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

  7. Operational Modal Analysis of Bridge Structure Based on DataDriven Stochastic Subspace Identification Algorithm%数据驱动随机子空间算法的桥梁运营模态分析

    Institute of Scientific and Technical Information of China (English)

    单德山; 徐敏

    2011-01-01

    以某自锚式悬索桥模型试验为研究背景,采用数据驱动随机子空间识别算法和改进稳定图方法对桥梁结构运营模态分析进行研究.为解决数据驱动随机子空间识别中的系统定阶和虚假模态问题,采用奇异熵增量进行系统定阶,并对稳定图进行改进,实现了虚假模态的识别与剔除,最终达到了精确识别桥梁结构模态参数的目的.采用模型试验在不同数据采集方案下的测试数据,识别该模型桥相应测试条件下的模态参数,将识别结果分别与ANSYS理论计算值、DASY-Lab模态参数识别结果进行比较,验证了所提方法及自编程序的正确性,该方法可应用于桥梁结构的运营模态分析中.%The model test of a self-anchored suspension bridge is taken as the research background, the data-driven stochastic subspace identification (Data-Driven SSI) algorithm and the improved stabilization diagram method are employed to study the operational modal analysis of bridge structure. For solving the problem of the system order determination and false modal parameters in the Data-Driven SSI, the singular entropy increment is introduced to determine the system order and to improve the stability diagram, the false modal parameters are therefore identified and eliminated and eventually the goal of accurately identifying the modal parameters of the bridge structure is attained. By using the testing data of the model test under different data acquisition cases, the modal parameters of the bridge structure Under the corresponding testing condi-tions are identified, the identified modal parameters are respectively compared to the values of the ANSYS theoretic calculation and to the results of DASYLab modal parameter identification. The correctness of the method proposed herewith and the self-complied program has been verified and the method can be applied to the operational model analysis of the bridge structure.

  8. Optimal design of initative horizontal bracing structure of middle tower column of southern cable stayed bridge of Xiazhang sea-crossing bridge%厦漳跨海大桥南汊斜拉桥索塔中塔柱主动横撑的设计计算

    Institute of Scientific and Technical Information of China (English)

    林寅

    2011-01-01

    本文介绍了厦漳跨海大桥南汊斜拉桥索塔施工中,为消除中塔柱倾斜塔柱根部混凝土的不良应力状态所采用的主动横撑结构的构造特点,以及考虑了施工因素的该结构的设计计算方法,确保中塔柱根部在施工过程中不开裂。该计算方法对类似工程具有一定的指导意义。%This paper intensively introduces the structural characteristics of the adoption of initiative horizontal bracing structure in order to eliminate the bad stress of concrete in the root of leaned tower column during the cable tower construction of Southern Cable Stayed Bridge of Xia Zhang Sea-crossing Bridge,as well as the structural design calculation method considering the construction factors,which can make sure that the root of leaned tower would not cracked during the construction process,and thie could be a reference for similar engineering.

  9. Polymeric salt bridges for conducting electric current in microfluidic devices

    Science.gov (United States)

    Shepodd, Timothy J.; Tichenor, Mark S.; Artau, Alexander

    2009-11-17

    A "cast-in-place" monolithic microporous polymer salt bridge for conducting electrical current in microfluidic devices, and methods for manufacture thereof is disclosed. Polymeric salt bridges are formed in place in capillaries or microchannels. Formulations are prepared with monomer, suitable cross-linkers, solvent, and a thermal or radiation responsive initiator. The formulation is placed in a desired location and then suitable radiation such as UV light is used to polymerize the salt bridge within a desired structural location. Embodiments are provided wherein the polymeric salt bridges have sufficient porosity to allow ionic migration without bulk flow of solvents therethrough. The salt bridges form barriers that seal against fluid pressures in excess of 5000 pounds per square inch. The salt bridges can be formulated for carriage of suitable amperage at a desired voltage, and thus microfluidic devices using such salt bridges can be specifically constructed to meet selected analytical requirements.

  10. Transient response of piles-bridge under horizontal excitation

    Institute of Scientific and Technical Information of China (English)

    朱斌; 陈仁朋; 陈云敏

    2003-01-01

    Moving ships and other objects drifting on water often impact a bridge's pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach. The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.

  11. Transient response of piles-bridge under horizontal excitation

    Institute of Scientific and Technical Information of China (English)

    朱斌; 陈仁朋; 陈云敏

    2003-01-01

    Moving ships and other objects drifting on water often impact a bridge' s pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach.The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.

  12. Sulfato-bridged ECE-pincer palladium(II) complexes: structures in the solid-state and in solution, and catalytic properties

    NARCIS (Netherlands)

    Kruithof, C.A.; Berger, A.; Dijkstra, H.P.; Soulimani, F.; Visser, T.; Lutz, M.; Spek, A.L.; Klein Gebbink, R.J.M.; van Koten, G.

    2009-01-01

    ECE-pincer sulfato palladium complexes (pincer = [C(6)H(3)(CH(2)E)(2)-2,6](-); E = SPh (), SMe (), S(t)Bu (), NMe(2) ()) were synthesized and characterized. In the solid-state (X-ray determinations) and exist as neutral ECE-pincer palladium sulfato complexes with a mu(2)-O,O' bridging sulfato ligand

  13. Shear capacity of ASR damaged structures – in-depth analysis of some in-situ shear tests on bridge slabs

    DEFF Research Database (Denmark)

    Hansen, Søren Gustenhoff; Barbosa, Ricardo Antonio; Hoang, Linh Cao

    2016-01-01

    This paper deals with the influence of alkali-silica reaction (ASR) on the shear capacity for concrete slabs without shear reinforcement. An experimental full-scale in-situ program consisting of four slabs from a bridge (Vosnæsvej) has been carried out and the results have been published in ref. [1...

  14. Global monitoring concept for bridges

    Science.gov (United States)

    Bergmeister, Konrad; Santa, Ulrich

    2000-06-01

    Knowledge of the integrity of in-service structures on a continuous time basis is an ultimate objective for owners and maintenance authorities. The development of a life extension and/or replacement strategy for highway structures is a crucial point in an effective bridge management system. A key component of such a bridge management system is a means of surveillance techniques and determining the condition of an existing structure within the normative and budgetary constraints. Recent advances in sensing technologies and material/structure damage characterization combined with current developments in computations and communications have resulted in a significant interest in developing diagnostic technologies for monitoring the integrity of and for the detection of damages of structures. To identify anomalies and deterioration processes, it is essential to understand the relationships between the signal measurements and the real occurred phenomena. Therefore, the comparison of measured and calculated data in order to tune and validate the mechanical and numerical model assumptions is an integral part of any system analysis. Finally, the interpreted results of all measurements should be the basis for the condition assessment and the safety evaluation of a structure to facilitate replacement and repair decisions.

  15. Heteropentanuclear Oxalato-Bridged nd–4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity

    KAUST Repository

    Kuhn, Paul-Steffen

    2015-08-10

    A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d–4f) metal complexes of the general formula (nBu4N)5[Ln{RuCl3(μ-ox)(NO)}4], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu4N)2[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by 13C NMR spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)]2− are coordinated to YIII and DyIII, respectively, with formation of [Ln{RuCl3(μ-ox)(NO)}4]5− (Ln=Y, Dy). While YIII is eight-coordinate in 2, DyIII is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu4N+ ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2–5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d–4f) analogues (nBu4N)5[Ln{OsCl3(ox)(NO)}4] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2–5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d–4f metal complexes 6–9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4 μM was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells.

  16. Structural, MALDI-TOF-MS, magnetic and spectroscopic studies of new dinuclear copper(II), cobalt(II) and zinc(II) complexes containing a biomimicking μ-OH bridge.

    Science.gov (United States)

    Núñez, Cristina; Bastida, Rufina; Macías, Alejandro; Valencia, Laura; Neuman, Nicolás I; Rizzi, Alberto C; Brondino, Carlos D; González, Pablo J; Capelo, José Luis; Lodeiro, Carlos

    2010-12-28

    The Py(2)N(4)S(2) octadentate coordinating ligand afforded dinuclear cobalt, copper and zinc complexes and the corresponding mixed metal compounds. The overall geometry and bonding modes have been deduced on the basis of elemental analysis data, MALDI-TOF-MS, IR, UV-vis and EPR spectroscopies, single-crystal X-Ray diffraction, conductivity and magnetic susceptibility measurements. In the copper and zinc complexes, a μ-hydroxo bridge links the two metal ions. In both cases, the coordination geometry is distorted octahedral. Magnetic and EPR data reveal weakly antiferromagnetic high spin Co(II) ions, compatible with a dinuclear structure. The magnetic characterization of the dinuclear Cu(II) compound indicates a ferromagnetically coupled dimer with weak antiferromagnetic intermolecular interactions. The intra-dimer ferromagnetic behaviour was unexpected for a Cu(II) dimer with such μ-hydroxo bridging topology. We discuss the influence on the magnetic properties of non-covalent interactions between the bridging moiety and the lattice free water molecules.

  17. The first 3D malonate bridged copper [Cu(O{sub 2}C-CH{sub 2}-CO{sub 2}H){sub 2}{center_dot}2H{sub 2}O]: Structure, properties and electronic structure

    Energy Technology Data Exchange (ETDEWEB)

    Seguatni, A., E-mail: seguatni@gmail.com [LBPC-INSERM U 698, Institut Galilee, Universite Paris XIII, 99, avenue J. B. Clement 93430, Villetaneuse (France); Fakhfakh, M. [Unite de recherche UR 12-30, Synthese et Structure de Materiaux Inorganiques, Faculte des Sciences de Bizerte, 7021 Zarzouna (Tunisia); Departement de Chimie, Universite du Quebec a Montreal, C.P. 8888, Succ. Centre-ville, Montreal, Que., H3C 3P8 (Canada); Smiri, L.S. [Unite de recherche UR 12-30, Synthese et Structure de Materiaux Inorganiques, Faculte des Sciences de Bizerte, 7021 Zarzouna (Tunisia); Gressier, P.; Boucher, F. [Institut des Materiaux Jean Rouxel, Universite de Nantes, CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes Cedex 3 (France); Jouini, N. [Departement de Chimie, Universite du Quebec a Montreal, C.P. 8888, Succ. Centre-ville, Montreal, Que., H3C 3P8 (Canada)

    2012-03-15

    A new inorganic-organic compound [Cu(O{sub 2}C-CH{sub 2}-CO{sub 2}H){sub 2}{center_dot}2H{sub 2}O] ([Cumal]) was hydrothermally synthesized and characterized by IR spectroscopy, thermal analysis and single crystal X-ray diffraction. [Cumal] is the first three-dimensional compound existing in the system Cu(II)-malonic acid-H{sub 2}O. Its framework is built up through carboxyl bridged copper where CuO{sub 6} octahedra are elongated with an almost D{sub 4h} symmetry (4+2) due to the Jahn-Teller effect. The magnetic properties were studied by measuring its magnetic susceptibility in the temperature range of 2-300 K indicating the existence of weak ferromagnetic interactions. The electronic structure of [Cumal] was calculated within the density functional theory (DFT) framework. Structural features are well reproduced using DFT structural optimizations and the optical spectra, calculated within the dielectric formalism, explain very well the light blue colour of the compound. It is shown that a GGA+U approach with a U{sub eff} value of about 6 eV is necessary for a better correlation with the experiment. - Graphical abstract: [Cu(O{sub 2}C-CH{sub 2}-CO{sub 2}H){sub 2}{center_dot}2H{sub 2}O]: the first 3D hybrid organic-inorganic compound built up carboxyl groups. The network presents a diamond-like structure achieved via carboxyl. Highlights: Black-Right-Pointing-Pointer A new organic-inorganic material with an unprecedented topology is synthesized. Black-Right-Pointing-Pointer Crystallographic structure is determined using single crystal X-ray diffraction. Black-Right-Pointing-Pointer Electronic structure is obtained from DFT, GGA+U calculation. Black-Right-Pointing-Pointer Framework can be described as formed from CuC{sub 4} tetrahedron sharing four corners. Black-Right-Pointing-Pointer This structure can be classified as an extended diamond structure.

  18. A Unique Prestressed Concrete Pedestrian Bridge in Spain

    OpenAIRE

    Ivorra Chorro, Salvador; Alvado Bañón, Joaquín; Crespo Zaragoza, Miguel Ángel

    2014-01-01

    This paper describes the so-called Kiss Bridge. This structure resembles a kiss, a subtle touch of structures. The beams have been structurally designed to adapt the Japanese art of paper folding called "origami." The material used for constructing the floating beams is white reinforced concrete in the form of folded shells. The two geometrically different parts have distinct structural behaviors. The length of the main pathway of both structures is over 60 m. The pedestrian bridge crosses an...

  19. Implementation of a bridge management system in the municipal environment

    CSIR Research Space (South Africa)

    Nordengen, Paul A

    2006-10-01

    Full Text Available is structures, which includes bridges and culverts. During the past few decades, little attention has been given by many municipalities to the overall condition of structures in general, and to a large extent structure rehabilitation projects that were... type of asset for which municipalities are responsible is structures, which includes bridges and culverts. During the past few decades, little attention has been given by many municipalities to the overall condition of structures in general, and to a...

  20. Bridge technology report

    CERN Document Server

    2013-01-01

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

  1. Measurements of bridges' vibration characteristics using a mobile phone

    Directory of Open Access Journals (Sweden)

    Z. M. C. Pravia

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

  2. The mechanics of ship impacts against bridges

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    a glancing blow between the ship and the bridge structure. This model is based on rigid body mechanics and well suited for inclusion in a probabilistic analysis procedure. Finally, some empirical expressions are presented which relate the energy absorbed by crushing of ship structures to the maximum impact...

  3. Knowledge integrated visual analysis system for in-depth management of bridge safety and maintenance

    Science.gov (United States)

    Wang, Xiaoyu; Dou, Wenwen; Vatcha, Rashna; Liu, Wanqiu; Chen, Shen-En; Lee, Seok-Won; Chang, Remco; Ribarsky, William

    2009-05-01

    Infrastructure safety affects millions of U.S citizens in many ways. Among all the infrastructures, the bridge plays a significant role in providing substantial economy and public safety. Nearly 600,000 bridges across the U.S are mandated to be inspected every twenty-four months. Although these inspections could generate great amount of rich data for bridge engineers to make critical maintenance decisions, processing these data has become challenging due to the low efficiency from those traditional bridge management systems. In collaboration with North Carolina Department of Transportation (NCDOT) and other regional DOT collaborators, we present our knowledge integrated visual analytics bridge management system. Our system aims to provide bridge engineers a highly interactive data exploration environment as well as knowledge pools for corresponding bridge information. By integrating the knowledge structure with visualization system, our system could provide comprehensive understandings of the bridge assets and enables bridge engineers to investigate potential bridge safety issues and make maintenance decisions.

  4. Construction techniques of super-length main cable of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Shen Liangcheng; Liang Jinda

    2011-01-01

    Taizhou Bridge is a highway three-pylon two-span bridge with span arrangement of 1 080 m + 1 080 m and the length of the main cable is more than 3 100 m. It is the longest cable in China. As the erection of the main cable needs to cross over three towers and the cables undulate acutely, general problems like the twist, spread and swell of strands and shedding of the zinc coating are prone to arise, which make it difficult to guarantee the quantity of cable traction construction. In this paper, the hauling, shaping and saddling of strands and sag adjusting are illustrated in detail and how to execute the refined construction control to guarantee the erection quality is also covered.

  5. The seismic response of concrete arch bridges (with focus on the Bixby Creek bridge Carmel, California)

    Energy Technology Data Exchange (ETDEWEB)

    Hoehler, M; McCallen, D; Noble, C

    1999-06-01

    The analysis, and subsequent retrofit, of concrete arch bridges during recent years has relied heavily on the use of computational simulation. For seismic analysis in particular, computer simulation, typically utilizing linear approximations of structural behavior, has become standard practice. This report presents the results of a comprehensive study of the significance of model sophistication (i.e. linear vs. nonlinear) and pertinent modeling assumptions on the dynamic response of concrete arch bridges. The study uses the Bixby Creek Bridge, located in California, as a case study. In addition to presenting general recommendations for analysis of this class of structures, this report provides an independent evaluation of the proposed seismic retrofit for the Bixby Creek Bridge. Results from the study clearly illustrate a reduction of displacement drifts and redistribution of member forces brought on by the inclusion of material nonlinearity. The analyses demonstrate that accurate modeling of expansion joints, for the Bixby Creek Bridge in particular, is critical to achieve representative modal and transient behavior. The inclusion of near-field displacement pulses in ground motion records was shown to significantly increase demand on the relatively softer, longer period Bixby Creek Bridge arch. Stiffer, shorter period arches, however, are more likely susceptible to variable support motions arising from the canyon topography typical for this class of bridges.

  6. Syntheses and Crystal Structures of Two Cyano-bridged Bimetallic Complexes [Ln(DMSO)2(H2O)(μ-CN)4Fe(CN)2](Ln= Ce and Eu, DMSO= Dimethylsulfoxide) with Layered Structure

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhen-Qian; CAI Li-Zhen; CHEN Wen-Tong; GUO Guo-Cong; HUANG Jin-Shun

    2008-01-01

    Two new bimetallic cyano-bridged complexes [Ln(DMSO)2(H2O)(μ-CN)4Fe(CN)2] (Ln = Ce 1, Eu 2) have been prepared by the grinding reaction method and structurally characterized by X-ray single-crystal structure analysis. Crystallographic data for 1: C10H14CeFeN6O3S2, Mr = 526.36, monoclinic, P2/n, a = 7.852(4), b = 10.729(5), c = 11.181(5) (A), β = 96.992(8)°, V = 935.0(7) A3, Z = 2, Dc = 1.870 g/cm3, μ = 3.421 mm-1, F(000) = 512, R = 0.0363 and wR = 0.0971; and those for 2: C10H14EuFeN6O3S2, Mr = 538.20, monoclinic, P2/n, a = 7.739(5), b = 10.668(7), c = 11.008(7) A, β = 96.943(3)°, V = 902.1(11) A3, Z = 2, Dc = 1.981 g/cm3, μ= 4.499 mm-1, F(000) = 522, R = 0.0345 and wR = 0.0855. In each complex the lanthanide ion is seven-coordinated in a pentagonal bipyramidal arrangement, and the Fe(Ⅲ) ion is in a nearly regular octahedral environment. The title complexes can be described as two-dimensional (2-D) stair-like structures, which are further connected by hydrogen bonds to form three-dimensional (3-D) frameworks.

  7. A robust metal-organic framework constructed from alkoxo-bridged binuclear nodes and hexamethylenetetramine spacers: crystal structure and sorption studies.

    Science.gov (United States)

    Ilyes, Elena; Florea, Mihaela; Madalan, Augustin M; Haiduc, Ionel; Parvulescu, Vasile I; Andruh, Marius

    2012-08-06

    A neutral 3D metal-organic framework, (3)(∞)[Cu(2)(mand)(2)(hmt)]·H(2)O (1), was constructed from binuclear Cu(2)O(2) alkoxo-bridged nodes, generated by the doubly deprotonated mandelic acid. The nodes are connected by hexamethylenetetramine (hmt) spacers, which act as biconnective bridging ligands, and by carboxylato groups. Channels are observed along the crystallographic c axis. The water molecules from the channels can be easily removed, preserving the architecture of the crystal, which is stable up to 280 °C. The Langmuir surface area was found to be 610 m(2) g(-1). The sorption ability of 1 was investigated using H(2) and CO(2).

  8. Bridges of the sella turcica - anatomy and topography.

    Science.gov (United States)

    Skrzat, Janusz; Mroz, Izabela; Marchewka, Justyna

    2012-01-01

    This paper presents anatomy and topography of the inconstant osseous bridges that may occur in the sella turcica region. The interclinoid bridge and the caroticoclinoid bridge can be formed in consequence of abnormal ossification of the dural folds or disturbances in development of the sphenoid bone. Their presence may be of clinical importance because of potential influence on the neurovascular structures passing in the vicinity of the clinoid processes of the sphenoid bone.

  9. Study and Application of Highway Bridge-erecting Machine JQC40A%JQC40A型公路架桥机的研究与应用

    Institute of Scientific and Technical Information of China (English)

    党春太; 叶文

    2000-01-01

    This paper introduces advanced bridge-erecting structure with taking beam laterally,bridge-erecting program and the work situation.Development trend of highway bridge-erecting machine in the future in China is predicted.

  10. Bridging Humanism and Behaviorism.

    Science.gov (United States)

    Chu, Lily

    1980-01-01

    Humanistic behaviorism may provide the necessary bridge between behaviorism and humanism. Perhaps the most humanistic approach to teaching is to learn how certain changes will help students and how these changes can be accomplished. (Author/MLF)

  11. State's First Bridge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Article with details on the state's first bridge that crossed the Noxubee River adjacent to the Noxubee National Wildlife Refuge Boundary. Details also included...

  12. Bridged Race Population Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — Population estimates from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 Office of Management and Budget (OMB) race and ethnicity...

  13. Synthesis and structural characterization of a novel peroxo bridged dinuclear cobalt(III) complex of succinimide showing three varieties of hydrogen bonding interactions

    Indian Academy of Sciences (India)

    Murat Taş; Orhan Büyükgüngör

    2009-05-01

    The reaction of aqueous cobaltous nitrate hexahydrate with the anion of succinimide (sucH) in the presence of excess ethylenediamine (en) in air results in the formation of a dinuclear complex -peroxo-bis[bis(ethylenediamine)succinimidato-cobalt(III)] dinitrate dihydrate, 1, in good yield. Compound 1 was characterized by elemental analysis, IR, visible spectra and magnetic susceptibility studies. The explosive nature of [Co(en)2(suc)(-O2)Co(en)2(suc)](NO3)2.2H2O, 1, precluded its thermal characterization. Compound 1 crystallises in the monoclinic space group 21/ and a half of the molecule, constitutes its asymmetric unit. In the centrosymmetric dinuclear complex 1, two Co(III) centres are linked by a planar peroxide bridge. Each cobalt atom is surrounded by four nitrogen atoms of ethylenediamine ligands, a nitrogen atom of succinimidato anion and an oxygen atom of peroxo bridge resulting in a slightly distorted {CoN5O} octahedron. Due to steric hindrance between the two Co(III) centres, the peroxide bridge is planar with a Co-O-O-Co torsion angle of 180°. The dinuclear complex cation, the nitrate anion and the lattice water are involved in three varieties of H-bonding interactions namely N-H$\\cdots$O, O-H$\\cdots$O and C-H$\\cdots$O.

  14. Investigation of Aerodynamic Interference of Double Deck Bridges

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-01

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

  15. LC-UV-Guided Isolation and Structure Determination of Lancolide E: A Nortriterpenoid with a Tetracyclo[5.4.0.0(2,4).0(3,7)]undecane-Bridged System from a "Talented" Schisandra Plant.

    Science.gov (United States)

    Shi, Yi-Ming; Cai, Song-Liang; Li, Xiao-Nian; Liu, Miao; Shang, Shan-Zhai; Du, Xue; Xiao, Wei-Lie; Pu, Jian-Xin; Sun, Han-Dong

    2016-01-01

    Lancolide E (1) featuring a complex tetracyclo[5.4.0.0(2,4).0(3,7)]undecane-bridged system that is constructed by an eight-, a three-, and two five-membered carbon rings in a sterically congested region was obtained in trace amounts from a "talented" schinortriterpenoid producer Schisandra lancifolia. Its structure was fully characterized by combining 2D NMR spectroscopy, theoretical calculations, and X-ray diffraction analysis. The biogenetic pathway of 1 was proposed to involve a Prins cyclization.

  16. Analysis and Experimental on Aircraft Insulation Thermal Bridge Effect

    Directory of Open Access Journals (Sweden)

    XIA Tian

    2017-06-01

    Full Text Available Two kinds of typical aircraft insulation structures were designed for the heat bridge in the metal ribs of aircraft insulation structures. In order to study the influence of heat bridge effect on thermal insulation performance, each configuration was analyzed by the transient heat transfer FEA, check point temperature was obtained in the hot surface temperature of 100 ℃, 200 ℃, 300 ℃, 424 ℃ respectively, and the validity of FEA was proved by insulation performance experiment. The result showed that the thermal bridge has a great influence to the insulation performance of insulation structure, and the thermal bridge influence should be considered adequately when the insulation structure designed. Additionally, the blocking method for thermal bridge is also put forward.

  17. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

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

  18. Framework for Bridges Maintenance in Egypt

    Directory of Open Access Journals (Sweden)

    Hesham Abd Elkhalek

    2016-01-01

    Full Text Available The traditional approaches for bridges maintenance is proven to be inefficient as they lead to random way of spending maintenance budget and deteriorating bridge conditions. In many cases, maintenance activities are performed due to user complaints. The objective of this paper is to develop a practical and reliable framework to manage the maintenance and repair activities of Bridges network in Egypt considering performance and budget limits. The model solves an optimization problem that maximizes the average condition of the network given the limited budget using Genetic Algorithm (GA. The main tasks of the system are bridge inventory, condition assessment, deterioration using markov model, and maintenance optimization. The developed model takes into account multiple parameters including serviceability requirements, budget allocation, element importance on structural safety and serviceability, bridge impact on network, and traffic. A questionnaire is conducted to complete the research scope. The proposed model is implemented in software, which provides a friendly user interface. The results of the framework are multi – year maintenance plan for the entire network for up to five years. A case study is presented for validating and testing the model with Data collected from “General Authority for Roads, Bridges and Land Transport” in Egypt.

  19. Construction Technology of Long Span Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    2000-01-01

    A large variety of construction methods are used during construction of major bridges, and in many cases the final structural system must be chosen with due respect to the construction process. Today the preferred construction methods are: the free-cantilever method, the launching method and the ......A large variety of construction methods are used during construction of major bridges, and in many cases the final structural system must be chosen with due respect to the construction process. Today the preferred construction methods are: the free-cantilever method, the launching method...

  20. Identification of a bridge's structural damage and vehicular parameters based on dynamic response sensitivity analysis%基于响应灵敏度分析的桥梁结构损伤和车辆参数的识别

    Institute of Scientific and Technical Information of China (English)

    张春丽; 吕中荣

    2016-01-01

    基于响应灵敏度分析利用车-桥耦合系统的加速度响应进行桥梁结构的局部损伤和车辆参数识别。在正问题中建立了连续桥梁结构和车辆耦合系统的有限元模型,利用 Newmark 直接积分法求出在移动车载作用下系统的动态响应,并进一步推导出动态响应对系统物理参数的时域响应灵敏度。在反问题中利用该响应灵敏度矩阵进行系统的有限元模型修正,识别出桥梁的局部损伤和车辆参数,讨论了人工噪声对识别结果的影响。算例表明该方法具有精度高、对测量噪声不敏感等特点。%Here,both local damages in a bridge's deck and parameters of moving vehicles were identified with a bridge-vehicle coupled system's dynamic responses induced by vehicles moving on the top of the bridge deck.The local damage is simulated by a reduction in the elemental flexural rigidity of the beam.The dynamic model of the bridge-vehicle coupled system was established using the finite element method and the dynamic responses of the system were obtained using Newmark direct integration method.In the inverse analysis,a dynamic response sensitivity-based finite element model updating approach was used to identify both local damages of the bridge deck in element level and parameters of vehicles.The solution was obtained iteratively with the penalty function method and the regularization from the measured structural dynamic responses.A multi-span continuous beam was studied as an numerical example to illustrate the correctness and efficiency of the proposed method.The effects of measurement noise,and measurement time duration on the identification results were investigated.The results indicated that the proposed method is efficient and robust for both damage identification and vehicular parametric identification;good identified results can be obtained with time histories of several measurement points.

  1. Field Tests and Simulation of Lion-Head River Bridge

    Directory of Open Access Journals (Sweden)

    Yao-Min Fang

    2007-01-01

    Full Text Available Lion-Head River Bridge is a twin bridge in parallel position. The east-bounded was designed and constructed as a traditional prestress concrete box girder bridge with pot bearings; and the west-bounded was installed with seismic isolation devices of lead rubber bearings. The behavior of the isolated bridge is compared with that of the traditional bridge through several field tests including the ambient vibration test, the force vibration test induced by shakers, the free vibration test induced by a push and fast release system, and the truck test. The bridges suffered from various extents of damage due to the Chi-Chi and the Chi-I earthquakes of great strength during the construction and had been retrofitted. The damage was reflected by the change of the bridges' natural frequencies obtained from the ambient vibration tests. The models of the two bridges are simulated by the finite element method based on the original design drawings. Soil-structure interaction was also scrutinized in this study. The simulation was then modified based on the results from the field tests. Dynamic parameters of bridges are identified and compared with those from theoretical simulation. The efficiency is also verified to be better for an isolated bridge.

  2. A pile-soil-bridge structure with dynamic interaction under Rayleigh wave excitation%Rayleigh波作用下桩-土-桥梁结构动力相互作用问题研究

    Institute of Scientific and Technical Information of China (English)

    谷音; 于志敏

    2011-01-01

    A 2D finite element model for a semi-infinite space with layered media and Rayleigh wave input was built by using equivalent viscous-elastic artificial boundary elements. The responses in free-field of even and layered media were computed. The results indicated that the finite element method has excellent estimation precision compared with the theore tical solutions. The dynamic response of a pile-soil-bridge structure with dynamic interaction under Rayleigh waves was analyzed. A typical rigid frame bridge was included in this case study. The influence of different site conditions, changes of location of soft interlayer, different Rayleigh wave input and pile length on Rayleigh wave propagation and the seismic response were considered. The influencing factors of the rigid frame bridge structure were also discussed.%基于等效粘弹性人工边界单元建立了可考虑成层介质及Rayleigh波输入的二维有限元时域模型,计算了Sayleih波作用下成层介质与均匀介质的自由场反应,与理论解比较表明有限元计算结果具有较好的工程精度.针对Rayleigh波作用下桩-土-典型刚构桥梁结构动力反应进行了分析,考虑了场地条件的不同、软夹层位置的改变、不同频率Rayleigh波的输入以及桩长对Rayleigh波传播与场地地震反应的影响,对影响因素进行了讨论.

  3. Estruturas mistas em madeira-concreto: uma técnica racional para pontes de estradas vicinais Timber-concrete composite structures: a rational technique for bridges of vicinal roads

    Directory of Open Access Journals (Sweden)

    Julio Soriano

    2009-07-01

    in rural buildings, making composite structures, constitutes a possible solution for presenting adequate structural and economical performances and durability too. In particular, the effectiveness of this structural system must be assured by a connection at the interface of the materials, and it can be of discrete (metallic elements: screws, steel bars, nails etc or continuous types (epoxy adhesive. Several kinds of civil construction applications can be contemplated by this structural system, as in restorations or construction of new bridges. In fact, along the vicinal roads, there is a large number of timber bridges that need restorations and there is a need to construct new bridges as well. General speaking, bridges are exposed to severe weather and loading conditions, and, thus, they must be carefully studied, so that the connection mechanisms can be more precisely evaluated, as well as the composite structure behavior during its entire life. In this context, by analyzing the several aspects that involve the performance of the timber-concrete composite structures and, also the mechanical behavior of the connections in these structures, we conclude, in this article, that this construction technique is feasible for bridges in vicinal roads. Further, additional research on the long-term loading effects, temperature and moisture variations, is necessary to improve the simulation models.

  4. The Effect of Deck Width Addition Toward Stability of Cable Stayed Bridge: Case Study of Siak Sri Indrapura Bridge, Riau

    Directory of Open Access Journals (Sweden)

    Supriyadi Bambang

    2017-01-01

    Full Text Available An aeroelastic interaction always take places in long-span bridge, i.e. the dynamic relationship between wind forces (aerodynamic and bridge structural motion (dynamics. Wind forces may lead to serviceability and safety problems, and may even cause instability of the whole bridge structure due to the flexibility nature of long span bridge structures.The slimer girder plate will make the structure more unstable as can be seen from the occurrence of lateral deformation. This paper presents the results analysis of cable stayed bridge that has total span of 640 m, two planes configuration of harp-typed hanger cable, the A shape pylons span along 320 m (main span,and side span of 160m. Structural analysis was conducted to determine the optimum ratio between width and spans of cable stayed bridge. The bridge was modeled with various width of 7 to 22 m. Structural modelling was conducted using SAP2000 software to analyze the structural stability of cable stayed bridge under wind load at speed of 35 m/s.The influence of wind loads to the cable stayed bridge stability can be seen based on the bridge deck deformation at the Y-axis (U2, in which for the width of the bridge deck of 7 m, 8 m, 9 m and 10 m, the deformation of U2 are 0.26 m; 0.17 m; 0.12 m and 0.10 m, respectively. Meanwhile, for bridge’s width of 11-22 m, the value of U2 axis deformation is relatively constant between 0.08 m to 0.07 m. This finding suggests that the ratio between width and length of bridge greatly affect the stability of the cable stayed bridge. Cable-stayed bridge, especially for concrete bridge, with two plain system having optimum ratio of width and length show no sign of an aerodynamic instability when fulfills the requirements of B ≥ L / 3.

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

    Directory of Open Access Journals (Sweden)

    Chinh Luong Minh

    2016-01-01

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

  6. Aerodynamic stability of cable-stayed-suspension hybrid bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan

    2005-01-01

    Three-dimensional nonlinear aerodynamic stability analysis was applied to study the aerodynamic stability of a cable-stayed-suspension (CSS) hybrid bridge with main span of 1400 meters, and the effects of some design parameters (such as the cable sag, length of suspension portion, cable plane arrangement, subsidiary piers in side spans, the deck form, etc.) on the aerodynamic stability of the bridge are analytically investigated. The key design parameters, which significantly influence the aerodynamic stability of CSS hybrid bridges, are pointed out, and based on the wind stability the favorable structural system of CSS hybrid bridges is discussed.

  7. Influences of Loads on Vehicles and Lanes on Reliability of Bridge Structures%车辆荷载和车道荷载对桥梁结构可靠度的影响

    Institute of Scientific and Technical Information of China (English)

    陈名扬; 王起才

    2012-01-01

    公路桥梁结构的整体计算采用车道荷载,结构的局部计算采用车辆荷载,车辆荷载与车道荷载的作用不得叠加.将采用这2种荷载设计的结构进行可靠度对比,结果表明,按车辆荷载设计的结构满足正常使用功能的可靠度偏低,更容易发生损坏,这些损坏会影响到结构的正常使用.提出通过调整重型车辆通过桥梁时的交通行驶规则,增大结构按正常使用极限状态设计时车辆荷载的代表值,从而提高按车辆荷载设计的结构可靠度.%Integral calculation for highway bridge structures adopts loads on lanes, local calculation for structures employs loads on vehicles, and the effects of loads on vehicles and lanes should not be superimposed. This paper compares reliabilities of structures designed by means of these two loads, the result show that the reliability of structures designed based on loads on vehicles to satisfy normal functions of use is lower and easier to damages, which will affect normal use of structures. The paper proposes to increase effect values of actions of loads on vehicles during design in limit state of normal use by adjusting traffic driving rules as heavy vehicles pass bridges so as to improve reliability of structures designed on the basis of loads on vehicles.

  8. Building bridges within the bacterial chromosome.

    Science.gov (United States)

    Song, Dan; Loparo, Joseph J

    2015-03-01

    All organisms must dramatically compact their genomes to accommodate DNA within the cell. Bacteria use a set of DNA-binding proteins with low sequence specificity called nucleoid-associated proteins (NAPs) to assist in chromosome condensation and organization. By bending or bridging DNA, NAPs also facilitate chromosome segregation and regulate gene expression. Over the past decade, emerging single-molecule and chromosome conformation capture techniques have investigated the molecular mechanisms by which NAPs remodel and organize the bacterial chromosome. In this review we describe how such approaches reveal the biochemical mechanisms of three NAPs that are believed to facilitate DNA bridging: histone-like nucleoid structuring protein (H-NS), ParB, and structural maintenance of chromosomes (SMC). These three proteins form qualitatively different DNA bridges, leading to varied effects on transcription and chromosome segregation.

  9. Vibration characteristics and damage detection in a suspension bridge

    Science.gov (United States)

    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.

  10. Strengthening of a railway bridge with NSMR and CFRP tubes

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bennitz, Anders; Danielsson, Georg

    2008-01-01

    Strengthening of structures with CFRP is today considered an accepted method to upgrade concrete structures. In this paper two different CFRP strengthening systems are combined to give extended service life to a Swedish double-trough-double-track railway bridge, constructed in concrete with a 10...... meter span. One system is the reliable NSMR (Near Surface Mounted Reinforcement) system while the other one is new; intended to strengthen the interior of a concrete structure, and the other system uses CFRP tubes integrated in drilled holes in the bridge. Both systems are used to increase tensile...... flexural strength of the slab transverse to the tracks. NSMR bars are positioned in the concrete cover on the underside of the bridge, while the new system is inserted in holes drilled through the bridge, in the cross direction and located in the upper part of the bridge slab. In connection...

  11. Advanced aerostatic analysis of long-span suspension bridges

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    As the span length of suspension bridges increases, the diameter of cables and thus the wind load acting on them, the nonlinear wind-structure interaction and the wind speed spatial non-uniformity all increase consequently, which may have unnegligible influence on the aerostatic behavior of long-span suspension bridges. In this work, a method of advanced aerostatic analysis is presented firstly by considering the geometric nonlinearity, the nonlinear wind-structures and wind speed spatial non-uniformity. By taking the Runyang Bridge over the Yangtze River as example, effects of the nonlinear wind-structure interaction, wind speed spatial non-uniformity, and the cable's wind load on the aerostatic behavior of the bridge are investigated analytically. The results showed that these factors all have important influence on the aerostatic behavior, and should be considered in the aerostatic analysis of long and particularly super long-span suspension bridges.

  12. A one-dimensional coordination polymer based on Cu3-oximato metallacrowns bridged by benzene-1,4-dicarboxylato ligands: structure and magnetic properties.

    Science.gov (United States)

    Croitor, Lilia; Coropceanu, Eduard B; Petuhov, Oleg; Krämer, Karl W; Baca, Svetlana G; Liu, Shi-Xia; Decurtins, Silvio; Fonari, Marina S

    2015-05-07

    A one-dimensional linear coordination polymer {[Cu3(μ3-OH)(2-pyao)3(bdc)]·6(H2O)}n () composed of trinuclear [Cu3(μ3-OH)(2-pyao)3](2+) metallacrown cores bridged by bis-carboxylato linkers has been obtained by treatment of copper(ii) fluoride with pyridine-2-aldoxime (2-pyaoH) ligand and benzene-1,4-dicarboxylic acid (H2bdc). Magnetic susceptibility measurements show strong antiferromagnetic interactions between Cu(ii) centers within the trinuclear metallacrown core with J = -430 cm(-1).

  13. The Internet Inter-Orb Protocol Security Bridge

    Directory of Open Access Journals (Sweden)

    Pawel Slowikowski

    1999-01-01

    Full Text Available In this paper, we present a security bridge for the Internet protocol of interoperability amongst CORBA objects and the Internet inter-ORB Protocol (IIOP. The bridge helps in making accessible objects in the Internet and makes possible the access control to them. The bridge was realized in the popular request broker the Visigenic's VisiBroker under Windows 95/NT and Solaris 2.X operating systems. We describe two ways of locating the bridge in the request broker. The first means uses one name domain of broker and is not transparent for client. The second one uses two name domains and provides objects protection on the level of the Naming Service and is transparent lor the client. We also describe the variant ofthe second means with using GateKeeper server to support IIOP tunneling within HTTP. We emphasize the importance of a firewall, cooperating with a bridge. which is required for the purpose of providing object protection. The paper presents an original conception of security managing, basing on the ideas of users, groups and resources defined using the standard terms of CORBA, IIOP and TCP/IP, that allows to control positively and negatively the access to classes (interfaces, objects and also to their individual methods. This conception was effectively implemented in a functioning bridge. Further chapters describe the foundations and some details of the bridge implementation sueli as the use ofthe Interface Repository, cache memory application, thread synchronization and the way of synchronization of the configuration applet with the bridge's objects. We discuss the influence of these solutions on the efficiency ofthe bridge and its source code portability. We also present the general structure of the component objects ofthe bridge with a scheme. ln the next part we characterize the implementation foundations ofthe bridge manager, realized as an applet in Java, with the stress on the possibility of the bridge configuration through the

  14. Reliability assessment of welded steel details in bridges using inspection

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard; Yalamas, T.

    2014-01-01

    of the membrane stresses are estimated using a generic bridge structure and traffic measurements. The optimal reliability level for a welded detail in a bridge subjected to fatigue are estimated by cost benefit-analysis taking into account the risk of human lives through the Life Quality Index. Since the optimal...

  15. Fragility curves for bridges under differential support motions

    DEFF Research Database (Denmark)

    Konakli, Katerina

    2012-01-01

    This paper employs the notion of fragility to investigate the seismic vulnerability of bridges subjected to spatially varying support motions. Fragility curves are developed for four highway bridges in California with vastly different structural characteristics. The input in this analysis consists...

  16. Probabilistic FE analysis of a cable stayed composite bridge

    NARCIS (Netherlands)

    Boer, A. de; Waarts, P.H.

    1999-01-01

    This paper describes the design of a new cable stayed composite bridge near Kampen in the Netherlands. In the design process, the safety of bridges is insured by means of partial safety factors for both strength and load parameters. As a result it is generally accepted that the structure as a whole

  17. 镶嵌式框架围护结构典型节点热桥模拟分析%Simulation Analysis on Thermal Bridge of Typical Nodes of Inlaid Frame Structure in Building Envelope System

    Institute of Scientific and Technical Information of China (English)

    周静; 高岩; 于崇明; 刘然

    2014-01-01

    The building envelope system of inlaid frame structure is introduced. Taking the typical weather condition in Beijing as the computational parameter, it analyzes the temperature distribution on thermal bridge of typical nodes of different inlaid frame structure in building envelope system with simula-tion, the result shows that the system can avoid condensation problems on thermal bridges. Studies about the heat flux distribution in different nodes indicate that the system can basically meet the design standard for energy efficiency of residential buildings in Beijing.%介绍了镶嵌式框架围护结构体系,以北京地区气候条件为计算参数,利用模拟软件,模拟分析了不同形式镶嵌式框架围护结构中典型节点的温度分布规律,结果表明该体系能够避免热桥部分产生结露问题;还分析了不同节点处的热流分布,表明该体系的节能效果可基本满足北京市居住建筑的节能设计要求。

  18. 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.

    Science.gov (United States)

    Kartal, Zeki

    2016-01-05

    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 3500-400cm(-1) and 3500-100cm(-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(CN) 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.

  19. Synthesis and crystal structure of binuclear copper(II) complex bridged by N-(2-hydroxyphenyl)-N'-[3-(diethylamino)propyl]oxamide: in vitro anticancer activity and reactivity toward DNA and protein.

    Science.gov (United States)

    Gao, Yang; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2013-08-01

    A new oxamido-bridged bicopper(II) complex, [Cu2(pdpox)(bpy)(CH3OH)](ClO4), where H3pdpox and bpy stand for N-(2-hydroxyphenyl)-N'-[3-(diethylamino)propyl]oxamide and 2,2'-bipyridine, respectively, has been synthesized and characterized by elemental analyses, molar conductivity measurements, infrared and electronic spectra studies, and X-ray single crystal diffraction. In the crystal structure, the pdpox(3-) ligand bridges two copper(II) ions as cisoid conformation. The inner copper(II) ion has a {N3O} square-planar coordination geometry, while the exo- one is in a {N2O3} square-pyramidal environment. There are two sets of interpenetrating two-dimensional hydrogen bonding networks parallel to the planes (2 1 0) and (21¯0), respectively, to form a three-dimensional supramolecular structure. The bicopper(II) complex exhibits cytotoxic activity against the SMMC7721 and A549 cell lines. The reactivity toward herring sperm DNA and bovine serum albumin revealed that the bicopper(II) complex can interact with the DNA by intercalation mode, and the complex binds to protein BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism.

  20. Synthesis and Crystal Structure of a One-dimensional Azido-bridged Manganese (II) Compound [Mn(N3)2(H2O)3·C6H12N4]n

    Institute of Scientific and Technical Information of China (English)

    CHEN Hui; WANG Wen-Guo; ZHANG Xiao-Feng; CHEN Chang-Neng; LIU Qiu-Tian

    2006-01-01

    A new one-dimensional azido-bridged manganese compound has been prepared and structurally characterized by X-ray diffraction. The complex [Mn(N3)2(H2O)3·C6H12N4]n crystallizes in space group Pnma with a = 6.5252 (5), b = 9.3226(7), c = 22.2070(15)(A), V = 1350.89(17)(A)3, Z = 4, Mr = 333.24, Dc = 1.639 g/cm3, μ= 1.005 mm-1 and F(000) = 692. The final refinement gave R = 0.0328 and wR = 0.0777 for 1085 observed reflections with I > 2σ(I). The structure contains [Mn- (N3)2(H2O)3]n polymeric chains and uncoordinated hexamethylenetetramine (HMTA) molecules with Mn/HMTA molar ratio of 1:1. The Mn atoms are bridged by end-to-end azido ligands to construct one-dimensional zig-zag infinite chains. Each Mn atom is six-coordinated by three N atoms of three azido ligands and three water O atoms, resulting in an octahedral geometry. Extending hydrogen- bonding interactions involving water O atoms, azido and HMTA N atoms link the chains and HMTA molecules into a three-dimensional network.