WorldWideScience

Sample records for arch bridges

  1. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

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

    2015-01-01

    A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post......-tensioning cables, the rise to span ratio, the height of the filling, and the height of the Super-Light Decks. We find that Pearl-Chain Bridges can be adjusted to resist specific moment loads by changing the normal force in the arch cross section by altering the above parameters. It is also found that the negative...

  2. Excitation of Arch and Suspension Bridges by Subwires

    Directory of Open Access Journals (Sweden)

    Noriaki Hiwatashi

    1993-01-01

    Full Text Available A force generation method using a subwire for arch and suspension bridges is proposed. The subwire is connected to the arch or the cable of the bridge through rollers. The uniform force produced by pulling and releasing the pretensioned subwires acts on the bridge as an externalforce. A new device called “the resonance force generator” is also developed to excite the bridges by applying a small force. To verify the proposed concept, a stress ribbon bridge was excited with the resonance force generator.

  3. Excitation of Arch and Suspension Bridges by Subwires

    OpenAIRE

    Noriaki Hiwatashi; Yoji Mizuta; Yutaka Ishihara; Itio Hirai

    1993-01-01

    A force generation method using a subwire for arch and suspension bridges is proposed. The subwire is connected to the arch or the cable of the bridge through rollers. The uniform force produced by pulling and releasing the pretensioned subwires acts on the bridge as an externalforce. A new device called “the resonance force generator” is also developed to excite the bridges by applying a small force. To verify the proposed concept, a stress ribbon bridge was excited with the resonance force ...

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

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2013-01-01

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

  5. Seismic vulnerability of historical arch type bridge structures in Italy

    OpenAIRE

    Qadir Bhatti, Abdul

    2009-01-01

    Italy is located on a earthquake prone area and old bridges were desinged without any seismic provision. In the years (2009), tremors were felt in Italy due to the strong earthquakes at Abruzzo, which highlight the earthquake threat to Italy. This study focuses on seismic vulnerability of arch type masonry bridge structures in Italy, designed primarily for gravity loads, when they are subjected to earthquakes. A case study has been carried out for the vulnerability study for a ...

  6. 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.

  7. 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.

  8. An Analytical Solution for Lateral Buckling Critical Load Calculation of Leaning-Type Arch Bridge

    Directory of Open Access Journals (Sweden)

    Ai-rong Liu

    2014-01-01

    Full Text Available An analytical solution for lateral buckling critical load of leaning-type arch bridge was presented in this paper. New tangential and radial buckling models of the transverse brace between the main and stable arch ribs are established. Based on the Ritz method, the analytical solution for lateral buckling critical load of the leaning-type arch bridge with different central angles of main arch ribs and leaning arch ribs under different boundary conditions is derived for the first time. Comparison between the analytical results and the FEM calculated results shows that the analytical solution presented in this paper is sufficiently accurate. The parametric analysis results show that the lateral buckling critical load of the arch bridge with fixed boundary conditions is about 1.14 to 1.16 times as large as that of the arch bridge with hinged boundary condition. The lateral buckling critical load increases by approximately 31.5% to 41.2% when stable arch ribs are added, and the critical load increases as the inclined angle of stable arch rib increases. The differences in the center angles of the main arch rib and the stable arch rib have little effect on the lateral buckling critical load.

  9. Approach for analyzing the ultimate strength of concrete filled steel tubular arch bridges with stiffening girder

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-cheng; XIE Xu; ZHANG He; CHEN Heng-zhi

    2007-01-01

    A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders isinvestigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.

  10. Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

    Directory of Open Access Journals (Sweden)

    Ding Youliang

    2016-01-01

    Full Text Available Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

  11. An Automatic Method for Geometric Segmentation of Masonry Arch Bridges for Structural Engineering Purposes

    Science.gov (United States)

    Riveiro, B.; DeJong, M.; Conde, B.

    2016-06-01

    Despite the tremendous advantages of the laser scanning technology for the geometric characterization of built constructions, there are important limitations preventing more widespread implementation in the structural engineering domain. Even though the technology provides extensive and accurate information to perform structural assessment and health monitoring, many people are resistant to the technology due to the processing times involved. Thus, new methods that can automatically process LiDAR data and subsequently provide an automatic and organized interpretation are required. This paper presents a new method for fully automated point cloud segmentation of masonry arch bridges. The method efficiently creates segmented, spatially related and organized point clouds, which each contain the relevant geometric data for a particular component (pier, arch, spandrel wall, etc.) of the structure. The segmentation procedure comprises a heuristic approach for the separation of different vertical walls, and later image processing tools adapted to voxel structures allows the efficient segmentation of the main structural elements of the bridge. The proposed methodology provides the essential processed data required for structural assessment of masonry arch bridges based on geometric anomalies. The method is validated using a representative sample of masonry arch bridges in Spain.

  12. Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-01-01

    Full Text Available In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

  13. Finite element model for arch bridge vibration dynamics considering effect of suspender length adjustment on geometry stiffness matrix

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yi-feng; WANG Rui; YING Xue-gang; CHEN Huai

    2006-01-01

    In this paper, we established a finite element (FEM) model to analyze the dynamic characteristics of arch bridges. In this model, the effects of adjustment to the length of a suspender on its geometry stiffness matrix are stressed. The FEM equations of mechanics characteristics, natural frequency and main mode are set up based on the first order matrix perturbation theory. Applicantion of the proposed model to analyze a real arch bridge proved the improvement in the simulation precision of dynamical characteristics of the arch bridge by considering the effects of suspender length variation.

  14. Dynamic Behavior of Tied-Arch Bridges under the Action of Moving Loads

    Directory of Open Access Journals (Sweden)

    Paolo Lonetti

    2016-01-01

    Full Text Available The dynamic behavior of tied-arch bridges under the action of moving load is investigated. The main aim of the paper is to quantify, numerically, dynamic amplification factors of typical kinematic and stress design variables by means of a parametric study developed in terms of the structural characteristics of the bridge and moving loads. The basic formulation is developed by using a finite element approach, in which refined schematization is adopted to analyze the interaction between the bridge structure and moving loads. Moreover, in order to evaluate, numerically, the influence of coupling effects between bridge deformations and moving loads, the analysis focuses attention on usually neglected nonstandard terms in the inertial forces concerning both centripetal acceleration and Coriolis acceleration. Sensitivity analyses are proposed in terms of dynamic impact factors, in which the effects produced by the external mass of the moving system on the dynamic bridge behavior are evaluated.

  15. Design and stability analysis of continuous skew tied-arch bridge over Bin Jiang River

    Institute of Scientific and Technical Information of China (English)

    Jiancheng YU; Hao TONG; Wei HUANG

    2008-01-01

    A tied arch bridge without wind bracing was built over the Bin Jiang River, with oblique angle of 20°. Its main design details are described and mechanical performances are analyzed. The stability analytical types are also introduced and the first elastic stability theory is used. A space finite element model has been built to analyze the stability performances in both construction and operation stages for single span or continuous, orthogonal or oblique bridge. The influence of stiffness of the end crossbeam is also analyzed. The result shows that out-plane buckling occur for a rigid tie and similar no matter whether it is single span or continuous and orthogonal or oblique. When there are more and stronger inner crossbeams, the influence of the end crossbeams on arch stability becomes unremarkable.

  16. Numerical analysis of ultimate strength of concrete filled steel tubular arch bridges

    Institute of Scientific and Technical Information of China (English)

    XIE Xu; CHEN Heng-zhi; Li Hui; SONG Shi-rui

    2005-01-01

    The calculation of ultimate bearing capacity is a significant issue in the design of Concrete Filled Steel Tubular (CFST)arch bridges. Based on the space beam theory, this paper provides a calculation method for determining the ultimate strength of CFST structures. The accuracy of this method and the applicability of the stress-strain relationships were validated by comparing different existing confined concrete uniaxial constitutive relationships and experimental results. Comparison of these results indicated that this method using the confined concrete uniaxial stress-strain relationships can be used to calculate the ultimate strength and CFST behavior with satisfactory accuracy. The calculation results are stable and seldom affected by concrete constitutive relationships. The method is therefore valuable in the practice of engineering design. Finally, the ultimate strength of an arch bridge with span of 330 m was investigated by the proposed method and the nonlinear behavior was discussed.

  17. Attenuating resonant behavior of a tied arch railway bridge using increased hanger damping

    OpenAIRE

    Andersson, Andreas; Karoumi, Raid

    2012-01-01

    In this paper, dynamic analyses and field measurements of a tied arch railway bridge is presented. Excessive vibrations of the hangers were obtained, caused by resonance during train passages. The resulting increase of the stress level and number of stress cycles were shown to decrease the fatigue service life significantly. The most critical section is a threaded turnbuckle connection of the hangers. Due to low damping of the hangers, more than 50 % of the cumulative fatigue damage was relat...

  18. Finding the lost arches of the Medieval Avignon's Bridge (Avignon, Provence, South France): a geoarchaeological approach

    Science.gov (United States)

    Ghilardi, M.; Vella, M. A.; Hermitte, D.; Parisot, J. C.; Dussouillez, P.; Fleury, T. J.; Provansal, M.; Delanghe-Sabatier, D.; Demory, F.; Mathé, P. E.; Quesnel, Y.; Danos, S.; Balossino, S.; Delpey, Y.; Hartmann-Virnich, A.; Berthelot, M.

    2012-04-01

    This papers aims to precisely locate the medieval arches of the so called Avignon's (Saint Bénézet) Bridge (South France) and to reconstruct the fluvial dynamics of the Rhone River from Early Medieval Times to the 19th century. Until now, just four remnant arches are still visible (near Avignon) and it is estimated that 22 arches (which represents a total length of approximately 920 meters) were built to span over one of the largest French Rivers. The late roman and early mediaeval dates of several foundation poles extracted from the river bed might suggest the existence of an earlier bridge, though it remains uncertain if any of such an earlier structure was still visible when the first mediaeval bridge was built. The mediaeval bridge was erected from 1177 until 1185 (in less than 10 years), but modified a few decades later when stone arches were erected, thus raising the road level substantially. The structure of the bridge being vulnerable, seasonal floods proved a neverending threat and cause of damage which was frequently repaired with masonry or wood. Final abandon of the edifice could be placed in the late 1660s - Early 1670s according to historical sources. Questions arose about the location of the "lost arches" and evident flood events dated back to the Little Ice Age (e.g. 1500 to 1850) could be responsible of the partial destruction of the bridge. Few archaeological, architectural, historical and palaeoenvironmental works have been undertaken in order to determine the precise shape of the Saint Bénézet Bridge at certain stages of its history. Since 2010, a joint team composed by laboratories affiliated to the French Public Research Centre (CNRS) and to Universities of Avignon and of Aix-Marseille 1 is trying to link the different phases of constructions/destructions of the monument with the fluvial dynamics of the Rhone River for the concerned period (ANR PAVAGE). The geoarchaeological approach adopted comprises bathymetric surveys (SONAR and

  19. GEOTECHNICAL MODELS OF THE ARCH FOUNDATIONS OF THE MASLENICA BRIDGE

    Directory of Open Access Journals (Sweden)

    Tomislav Novosel

    1998-12-01

    Full Text Available On the site of Maslenica bridge structural tectonic, geophysical and engineering geological investigations, geotechnical drilling and laboratory sample testings were performed. Maslenica anticline is characteristic for the investigated area. It is built from the limestone of Cretaceous age. The anticline has an asymmetrical form with the vergence of the axial plane towards the north. Reverse faults with recent activities are present. The recent activity was proved by the discovery of the broken stalactite with the displacement of 11 cm, whose age is 36000 years. On quite young stalactites (stalagmites in the cave on the west side, no displacements were noticed. For the next period of 500 years the maximal possible displacement of 2.0 cm is foreseen. Smaller caves with the dimensions of 1 m3, were formed on the intersections of the reverse faults and greater joints. The canyon Novsko ždrilo was formed in the fault shear zone with tectonic transport to the right. According to the range of fracture, three characteristic types of rock masses were separated by engineering geological investigations. According to »Geomechanical classification« (RMR the first type corresponds to II to III class, while the second type corresponds to IV class, and the third type corresponds to V class (mylonite. Because of the complexity of the terrain structure, original engineering geological bases of design have not enabled the direct application of the analysis of stress-strain behaviour. Because of that the simplified geotechnical models were done. They enabled the projecting of foundation in the rock mass and renewal of poor quality rock mass.

  20. Reinforcement and numerical analysis on the corbel of a half-through arch bridge

    Institute of Scientific and Technical Information of China (English)

    LIAO Bi-hai; WANG Yuan-han; CHENG Hong-guang; MIAO Yu

    2009-01-01

    Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial software ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.

  1. Traveling wave effect on the seismic response of a steel arch bridge subjected to near fault ground motions

    Institute of Scientific and Technical Information of China (English)

    Xu Yan; George C Lee

    2007-01-01

    In the 1990s, several major earthquakes occurred throughout the world, with a common observation that near fault ground motion (NFGM) characteristics had a distinct impact on causing damage to civil engineering structures that could not be predicted by using far field ground motions. Since then, seismic responses of structures under NFGMs have been extensively examined, with most of the studies focusing on structures with relatively short fundamental periods, where the traveling wave effect does not need to be considered. However, for long span bridges, especially arch bridges, the traveling wave (only time delay considered) effect may be very distinct and is therefore important. In this paper, the results from a case study on the seismic response of a steel arch bridge under selected NFGMs is presented by considering the traveling wave effect with variable apparent velocities. The effects of fling step and long period pulses of NFGMs on the seismic responses of the arch bridge are also discussed.

  2. 斜靠式系杆拱桥拱肋安装技术%The Installation Technology of Arch Ribs of Leaning Type CFST Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    柳明佳

    2011-01-01

    通过南通新开北路通启运河大桥施工实例,介绍了斜靠式系杆拱桥的拱肋安装施工技术,并对影响拱肋安装精度的因素进行了分析,对如何控制做了简述。%This article introduces the installation and construction technology of arch ribs of leaning-type CFST arch bridge with the construction example of Nantong Tongqi canal bridge on North Xinkai road. And it also analyzes the factors of the accuracy of rib installation and makes a brief introduction of how to control.

  3. Longitudinal force in continuously welded rail on long-span tied arch continuous bridge carrying multiple tracks

    Institute of Scientific and Technical Information of China (English)

    YAN Bin; DAI Gong-lian; GUO Wen-hua; XU Qing-yuan

    2015-01-01

    Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube (CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a (77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail (CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load. Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.

  4. Stochastic subspace identification for operational modal analysis of an arch bridge

    Science.gov (United States)

    Loh, Chin-Hsiung; Chen, Ming-Che; Chao, Shu-Hsien

    2012-04-01

    In this paer the application of output-only system identification technique, known as Stochastic Subspace Identification (SSI) algorithms, for civil infrastructures is carried out. The ability of covariance driven stochastic subspace identification (SSI-COV) was proved through the analysis of the ambient data of an arch bridge under operational condition. A newly developed signal processing technique, Singular Spectrum analysis (SSA), capable to smooth noisy signals, is adopted for pre-processing the recorded data before the SSI. The conjunction of SSA and SSICOV provides a useful criterion for the system order determination. With the aim of estimating accurate modal parameters of the structure in off-line analysis, a stabilization diagram is constructed by plotting the identified poles of the system with increasing the size of data Hankel matrix. Identification task of a real structure, Guandu Bridge, is carried out to identify the system natural frequencies and mode shapes. The uncertainty of the identified model parameters from output-only measurement of the bridge under operation condition, such as temperature and traffic loading conditions, is discussed.

  5. The behaviour of a historic masonry arch bridge regarding dynamic loads

    Directory of Open Access Journals (Sweden)

    Yesid Mauricio Ospina

    2010-05-01

    Full Text Available This article describes the analysis of a historic brick arch bridge constructed in Colombia during the 18th century for predicting its behavior in response to loads produced by seismic activity and determining its vulnerability. Two studies were carried out prior to the seismic analysis to obtain basic information regarding the structure's overall behavior (modal analysis and linear static analy- sis, both stemming from a three-dimensional model constructed by the finite elements method. Seismic excitation was simulated in the conditions proposed by 1998 Colombian seismic-resistant norms (NSR-98. The results obtained agreed with the bridge’s history and with its response to earthquakes; the comparison between seismic loads and the resistance capacity of the materials constituting the structure confirms the vulnerability of these types of constructions regarding localised damage and the possibility of collapse. The results suggest that this procedure can be applied to other historic structures in Colombia.

  6. Data processing in subspace identification and modal parameter identification of an arch bridge

    Science.gov (United States)

    Fan, Jiangling; Zhang, Zhiyi; Hua, Hongxing

    2007-05-01

    A data-processing method concerning subspace identification is presented to improve the identification of modal parameters from measured response data only. The identification procedure of this method consists of two phases, first estimating frequencies and damping ratios and then extracting mode shapes. Elements of Hankel matrices are specially rearranged to enhance the identifiability of weak characteristics and the robustness to noise contamination. Furthermore, an alternative stabilisation diagram in combination with component energy index is adopted to effectively separate spurious and physical modes. On the basis of identified frequencies, mode shapes are extracted from the signals obtained by filtering measured data with a series of band-pass filters. The proposed method was tested with a concrete-filled steel tubular arch bridge, which was subjected to ambient excitation. Gabor representation was also employed to process measured signals before conducting parameter identification. Identified results show that the proposed method can give a reliable separation of spurious and physical modes as well as accurate estimates of weak modes only from response signals.

  7. Explosion on the reinforcement design and construction methods of stone arch bridge%石拱桥加固设计及施工方法探讨

    Institute of Scientific and Technical Information of China (English)

    周勇

    2015-01-01

    结合工程案例,对拱背增大截面加固石拱桥的设计方案进行了介绍,并对拱上建筑拆除、主拱圈加固、更换拱腔填料等施工工艺进行了阐述,通过实践证明,采用该加固方法既可大大减少工程投资,又能提高石拱桥的整体承载能力,具有显著的社会和经济效益,对石拱桥的加固具有积极的推广意义。%Combining with engineering examples,the paper introduces the design scheme of arch enlarging section reinforced stone arch bridge, and describes top arch building demolishment,main arch circle reinforcement,and replacing arch filling materials and other construction technol-ogies. Practice proves that:the reinforcement methods can not only reduce engineering investment,but also improve integral bearing capability of stone arch bridge,and has obvious social and economic benefits,which has positive meaning for reinforcing stone arch bridge.

  8. Optimal Design of Concrete Tied Arch Bridge%混凝土系杆拱桥优化设计

    Institute of Scientific and Technical Information of China (English)

    乔建东; 吴慧山; 杨伟

    2015-01-01

    为探讨混凝土系杆拱桥的多参数优化设计方法,选取计算矢高、拱肋截面尺寸、系梁截面尺寸、吊杆面积和系梁纵向预应力筋数目作为设计变量,规范限值为约束条件,全桥总造价为目标函数,建立了混凝土系杆拱桥的优化模型;采用大型通用程序ANSYS和桥梁结构平面分析程序,结合混合整型序列二次规划法,混合编程求解优化模型.以某拱桥为工程背景,建立并求解优化模型,将优化结果与设计值进行比较.结果表明:系梁混凝土用量减少40.98%,拱肋混凝土用量减少23.81%,预应力钢筋数目减少28.23%,全桥材料总造价降低28.63%.%In order to investigate the multi-parameter optimal design method of concrete tied arch bridges,an optimal model was established. In this model,rise,cross section dimensions of arch ribs and tied beams,area of each suspender and number of pre-stressed steel bars in each hole are selected as the design variables,code values as the constraint conditions,and total cost of whole bridge as the objective function. A plane analysis program for bridge structure,the software ANSYS and the mix-integer sequence quadratic program method were used together to program and solve the optimal model. The optimal model was solved by taking an arch bridge as engineering background,the optimal results were compared with the design values. The comparison results show that the concrete consumptions of tied beams and arch ribs is respectively reduced by 40 . 98% and 23 . 81%,the number of pre-stressed steel bars is decreased by 28 . 23%,and the total material cost is cut by 28 . 63%.

  9. 结合梁桥面系异形钢箱拱肋系杆拱桥设计%Design of Special-shaped Steel Box Arch Rib Bowstring Arched Bridge of Bonding Beam Deck System

    Institute of Scientific and Technical Information of China (English)

    李文勃

    2009-01-01

    The main bridge of Putian Chenggang Avenue Bridge crossing Molan River is the special-shaped bowstring arched bridge of 2-span simple-supported double-rib half-through steel box arch rib bonding beam deck system. The single span is 72 m long and the bridge is 47.5 m wide with city-Class A load and double-direction of 8 lanes. Taking the preliminary design and construction drawing design of this bridge as the basis, the article introduces the scheme study of bridge type, structural design of main bridge and analysis of structural calculation of the special-shaped bowstring arched bridge, and analyzes some technical characteristics of this bridge. The design method of the main bridge inclined crossed with the curve river, the design thinks of bonding beam in the arched bridge, the temporary constructed supporting point for improving the structural bearing, and the design method of special arch rib modeling can be referred for the design of the similar bridges.%莆田城港大道跨木兰溪大桥主桥是两跨简支的双肋下承式钢箱拱肋结合梁桥面系的异形系杆拱桥,单跨跨径72m,桥宽47.5m,城一A级荷载,双向8车道.该文以该桥的初步设计和施工图设计为基础,介绍了异形系杆拱桥的桥型方案研究、主桥结构设计、结构计算分析等内容,并分析了该桥的一些技术特点.该桥的弯曲河道斜交主桥设计方法、结合梁在拱桥中的设计思想、结合梁横梁设置临时支点改善结构受力、独特拱肋造型的设计方法等内容,可供类似桥梁设计时参考.

  10. Construction Technology of Support Lifting of Steel Arch Bridge across Railway%钢管拱桥跨铁路支架吊装施工技术

    Institute of Scientific and Technical Information of China (English)

    张翠芹

    2011-01-01

    The article summarizes and describes the construction technology and processes of support lifting of the steel arch bridge by the construction practice of Shihuan Road 307 State Road East Interchange, which has a good guide for the steel arch bridge, especially the construction tool of steel arch bridge under limited construction.%文章通过石环公路307国道东互通立交桥的施工实践,总结介绍了钢管拱桥支架吊装法施工技术和工艺.对钢管拱桥,特别是施工场地受限条件下的钢管拱桥施工具有很好的指导作用.

  11. A comparative study between China and U.S. on seismic design philosophy and practice of a long span arch bridge

    Institute of Scientific and Technical Information of China (English)

    Xu Yan; George C Lee; Fan Lichu; Hu Shide

    2006-01-01

    This paper presents the first of a series of case studies on the seismic design of long span bridges (cablestayed bridges, suspension bridges and arch bridges) under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that (1) the selected near field ground motions cause larger responses to key components (critical sections) of the bridge (such as arch rib ends) with a maximum increase of more than twice those caused by the site specific ground motions; (2) piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and (3) large vertical components of near field ground motions may not significantly affect the bridge's internal forces provided that their peak acceleration spectra ordinates only appear at periods

  12. The Reinforcement and Reconstruction Design of a Hollow Type Arch Bridge%某空腹式拱桥加固改造设计

    Institute of Scientific and Technical Information of China (English)

    聂立力

    2014-01-01

    拱桥最为我国最常用的一种桥梁形式,其使用时间较长时容易出现病害。本文以一山区空腹式拱桥为例,对其病害情况、加固措施及施工要点等进行了分析与研究,希望能为相关工程提供借鉴。%Arch bridge is the most commonly used bridge form in China, which can easily cause diseases when use for a long time. This article takes a hol ow type arch bridge in a mountain as an example and carries on the analysis and study of the disease situation, the reinforcement measures, and the main points of construction, and hope to provide reference for related projects.

  13. 多种加固方法应用于双曲拱桥主拱圈的提载加固%Reinforcement for Improving Bearing Capacity of A Double Arch Bridge Main Arch by Strengthen Methods

    Institute of Scientific and Technical Information of China (English)

    黄伟; 申波; 薛守宝; 梁影

    2012-01-01

    In this paper, reinforcement for improving the bearing capacity of a double arch bridge is studied. Based on the test results of a double-arched bridge of Anshun in Guizhou province, the strengthening program of the main arch is proposed. At the section of arch feet, the moment bearing capacity is improved by enlarged upper edge concrete and lower edge concrete of the section, the section is changed to box section. At the other section of the arch, the negative moment bearing capacity is improved by enlarged upper edge concrete of the section, and the positive moment bearing capacity is improved. For the deficiencies of the positive moment bearing capacity, the bonding steel plate is recommended at the arch rib of the other section. The results show that the reinforcement methods can improve load level of the bridge effectively. The construction of the bridge is convenient and can satisfy the design goals.%针对双曲拱桥的提载加固,基于贵州省安顺市木浪河大桥的检测结果,提出了在主拱圈的拱脚上缘增大截面、下缘增大截面改造为箱形断面,以提高拱脚抵抗负弯矩、正弯矩的承载能力;对其它截面采用拱背增大截面以提高抵抗负弯矩的承载能力,相应也提高了抵抗正弯矩的承载能力;对正弯矩承载能力不足的截面,采用粘贴钢板的加固方法.结果表明:采用这种提载加固的设计方法,达到了提高荷载等级的目的,同时方便施工,便于达到加固效果.

  14. Construction Points of Tied-arch Bridge across High-speed Rail:Case Study of the Construction of Tied-arch Bridge across Jihuang High-speed Rail%高速铁路桥施工要点探析--以跨绩黄高速铁路系杆拱桥施工为例

    Institute of Scientific and Technical Information of China (English)

    杨乐绪

    2015-01-01

    系杆拱桥是一种外形美观、成本较低的梁拱组合体系桥,钢管混凝土组合材料在系杆拱桥中的应用能够解决材料高强化、施工轻型化问题,有助于提高拱桥材料的稳定性、耐久性、抗腐蚀性、抗压强度等性能,施工快捷方便,造价较低,且可以缩短工期,因而得到十分广泛的应用。本文以跨绩黄高速大桥1-96m下承钢管混凝土系杆拱桥为例对其施工要点进行分析,以此得出系杆拱桥的优越性。%Tied-arch bridge is the girder and arch combination bridge with beautiful appearance and low-cost. The application of steel concrete composite materials in the tied-arch bridge can solve the problems of highly fortified material and lightweight construction, can improve the stability, durability, corrosion resistance, compressive strength and other properties of bridge material, and its construction is convenient, cost is low, and duration is short, and it has a very wide range of applications. This paper analyzes the construction points of 1-96m below bearing steel concrete tied-arch bridge across the Jihuang high-speed rail to obtain superiority of tied-arch bridge.

  15. Research on Multi-Parameter of Butterfly Arched Bridge Stability%蝴蝶拱桥稳定性多参数影响研究

    Institute of Scientific and Technical Information of China (English)

    段锋

    2012-01-01

    以某蝴蝶拱桥为工程背景,建立该桥的空间有限元计算模型,分4个工况计算了该桥的稳定安全系数。通过改变拱肋外倾角度、拱肋刚度、端横梁刚度以及吊杆布置形式计算了不同设计参数下结构在恒栽工况以及恒载+活载工况的失稳特征值。结果表明,拱肋的刚度对稳定性起着决定性作用;吊杆的布置形式只改变拱肋的面内刚度,对于面外刚度没有影响。%Taking some butterfly arched bridge as the engineering background, the study establishes tile spatial finite ele- ment computation model of the bridge, and the stability safety index is calculated in four kinds of construction conditions. Through the change of arch rib camber angle, rigidity of the arch rib, the end beam rigidity as well as the arrangement of suspension bar, imbalance eigen values of the structure are calculated in the dead load operating mode as well as the dead load + live load operating mode. The result indicates that, the arch rib rigidity plays a decisive role in the stability; The suspension bar arrangement only changes the arch rib in plane rigidity and has nothing to do without plane rigidity.

  16. Reverse engineering of mandible and prosthetic framework: Effect of titanium implants in conjunction with titanium milled full arch bridge prostheses on the biomechanics of the mandible.

    Science.gov (United States)

    De Santis, Roberto; Gloria, Antonio; Russo, Teresa; D'Amora, Ugo; Varriale, Angelo; Veltri, Mario; Balleri, Piero; Mollica, Francesco; Riccitiello, Francesco; Ambrosio, Luigi

    2014-12-18

    This study aimed at investigating the effects of titanium implants and different configurations of full-arch prostheses on the biomechanics of edentulous mandibles. Reverse engineered, composite, anisotropic, edentulous mandibles made of a poly(methylmethacrylate) core and a glass fibre reinforced outer shell were rapid prototyped and instrumented with strain gauges. Brånemark implants RP platforms in conjunction with titanium Procera one-piece or two-piece bridges were used to simulate oral rehabilitations. A lateral load through the gonion regions was used to test the biomechanical effects of the rehabilitations. In addition, strains due to misfit of the one-piece titanium bridge were compared to those produced by one-piece cast gold bridges. Milled titanium bridges had a better fit than cast gold bridges. The stress distribution in mandibular bone rehabilitated with a one-piece bridge was more perturbed than that observed with a two-piece bridge. In particular the former induced a stress concentration and stress shielding in the molar and symphysis regions, while for the latter design these stresses were strongly reduced. In conclusion, prosthetic frameworks changed the biomechanics of the mandible as a result of both their design and manufacturing technology.

  17. 中承单肋式钢拱桥静力性能分析%Half-through single-rib steel arch bridge static performance analysis

    Institute of Scientific and Technical Information of China (English)

    高铭霖

    2015-01-01

    Taking Xiamen Tianyuan Bridge as the project background , based on static-state load test , the paper collects strain data and deflection data , analyzes static performance of bridge , provides technical support for conservation and management of half -through single-rib steel arch bridge.%本文以厦门市天圆大桥为工程背景,通过静力荷载试验,测试桥梁主要控制截面的应变、挠度数据,分析桥梁的静力性能,为今后中承单肋式钢拱桥的养护管理提供技术依据。

  18. 浅论拱桥的技术进步与挑战%On Technical Advancement and Challenge of Arch Bridges

    Institute of Scientific and Technical Information of China (English)

    李亚东; 姚昌荣; 梁艳

    2012-01-01

    The basic characteristics of span length development of some arch bridges (including the steel, reinforced concrete and concrete-filled steel tube arch bridges) having been built in the world in the rcccnt one century are surveyed and with reference to the thc basic characteristics of the techniques having been applied to construction of the different types of the bridges, the construction methods for the bridges arc summrized into three major kinds, that is, the scaffolding method, cantilever method and large component shifting method. On the basis of the techniques for the construction of the bridges, several technical issues on the structures and durability of the arch bridges in China in their development process are studied. To clarify the relationship between the structures and architectural style of the bridges and the relationship between the mechanics and aesthetics, the determination of a bridge type scheme is divided into two aspects of the bridge type selection and bridge configuration and the related basic principles are put forward, that is, for the bridge type selection, the principle is that of the "clear force conditions and simple structure" , for the bridge configuration, the principle is the "simple configuration and integral coordination" , for the construction investment, the principle is the "easy construction and rational cost" while for thc features of the bridge itself, the principle is the "harmony with environment and distinguished features" and further all these principles mentioned herewith are elaborated and analyzed by way of case study of practical bridges.%通过分析百年来拱桥(包括钢拱桥、钢筋混凝土拱桥、钢管混凝土拱桥)跨度发展的基本特点,并根据各种拱桥施工技术的基本特征,把拱桥施工方法分为3大类,即支架法、悬臂法和大件转移法.基于拱桥施工技术,探讨了中国拱桥发展历程中的构造、耐久性等技术问题.为厘清桥梁结构与建筑的关

  19. 大跨度连续梁拱组合桥梁轨互制特征%Track-bridge Interaction of Combination Bridge with Long-span Continuous Beam Arch

    Institute of Scientific and Technical Information of China (English)

    王伟民

    2016-01-01

    To study the characteristics of track-beam interaction of the combination bridge with long-span continuous beam arch, a rigid frame arch combination bridge with (34+160+34) m continuous steel-box girder tied-arch on Meizhou-Chaoshan railway line is referenced. A track-arch-beam-pier integration space model is established to simulate track longitudinal resistance with ideal elastic-plastic model. The distribution of track longitudinal force is analyzed. The girder stress, the rotation angle at bridge end, and the longitudinal reaction at pier bottom are compared with or without track effects. Results show that rail longitudinal force is great at the beam end farther away from the fixed support of the combination bridge with continuous beam arch; the maximum expansion stress reaches to 114. 0 MPa, but the rail strength meets the requirements without rail expansion devices;the track structure has great impact on the stress of girder under the action of temperature load or braking force and it also has great impact on rotation angle at bridge end and on the distribution of longitudinal reaction at pier bottom.%为研究大跨度连续梁拱组合桥梁轨相互作用特征,以梅汕线上某(34+160+34) m刚架系杆拱钢箱连续梁组合桥为背景,采用理想弹塑性模型模拟线路纵向阻力,建立“轨拱梁墩”一体化空间模型,对钢轨纵向力的分布规律进行分析,对是否考虑轨道作用下的主梁应力、梁端转角、墩底纵向反力进行比较。结果表明:连续梁拱组合桥远离固定支座的梁端处钢轨纵向力较大,其中最大伸缩应力达到114.0 MPa,在不设钢轨伸缩调节器时钢轨强度仍满足要求;轨道结构对温度荷载和制动力作用下的主梁应力影响较大;轨道结构对梁端转角及墩底纵向反力的分配亦有较大影响。

  20. Enlarged Cross-section of The Stone Arch Bridge Strengthened by Technology Application%增大截面法加固石拱桥的技术应用

    Institute of Scientific and Technical Information of China (English)

    吴跃梓; 章劲松

    2012-01-01

    石拱桥是极具中华民族气息与特色的桥型,该桥型结构实用、美观.然而随着时代的变迁及交通运输业的发展,大量的石拱桥出现了各种各样的病害,很多桥甚至已发展成危桥.为改善交通状况,消除安全隐患,结合当前经济状况,加固利用旧危石拱桥是合理的.石拱桥加固的方法很多,结合工程实例重点阐述增大截面加固法加固石拱桥的基本原理、方法和步骤.%Stone arch bridge is a Chinese national flavor and characteristics of the bridge, the bridge type structure, beautiful and practical. However, with the change of times and the development of transportation industry, large stone arch bridges the emergence of a variety of diseases, many bridges has developed the deserted bridge. In order to improve traffic conditions, to eliminate potential safety problems, combined with the current economic situation, strengthening the old stone arch bridge is reasonable. Stone arch bridge reinforcement method, this paper focuses on the section- enlarging reinforcing method for reinforcing stone arch bridge, the basic principle of the method and steps.

  1. 双肋斜拉拱桥横向稳定性的实用计算%Practical Calculation of the Lateral Destabilization of Double Rib Cable-stayed Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    陆伟; 罗世东

    2011-01-01

    The cable-stayed arch bridge is a new form of bridge structure, which combines characteristis of the cable-stayed bridge and the arch bridge. The stability of arch is different from the normal arch bridge because the cable shares the load with the arch rib. On the basis of the energy principle, the text deduces a practical method for calculation of the lateral destabilization critical loading of the double rib cable-stayed arch under the premise of considering the factors of the stiffness of bridge floor and non-oriented conservative loadings of hanger and cable. The precision of the method is verified via an example. Analysis on the influence of parameters of the cable-stayed arch bridge on its lateral destabilization critical loading is made with the practical method. The parameters include the pretension stress, the inclination of cable, the scope of cables arranged on the arch and the distance between bridge tower and arch.%斜拉拱桥是一种将斜拉桥和拱桥相结合的新型桥梁结构形式,索拱共同受力使得拱的稳定性区别于一般拱桥.本文基于能量原理,在综合考虑桥面刚度、吊杆非保向力、斜拉索非保向力的前提下,推导双肋斜拉拱横向失稳临界荷载的实用计算方法,并通过算例验证实用计算方法的正确性,借助实用方法分析斜拉索参数:斜拉索预张拉力、斜拉索倾角、在拱上布索范围、主塔与拱的距离等对双肋斜拉拱横向失稳临界荷载的影响.

  2. Live-Load Testing and Finite-Element Analysis of a Steel Cantilever Deck Arched Pratt Truss Bridge for the Long-Term Bridge Performance Program

    OpenAIRE

    Laurendeau, Matthew P.

    2011-01-01

    The Long Term Bridge Performance (LTBP) program is an organization within the Federal Highway Administration that inspects, tests, analyzes, and observes, for an extended period of time, a variety of bridge types throughout the United States. Part of the program includes periodic testing of select bridges of a span of 20 years. The Kettle River Bridge located outside of Sandstone, Minnesota was selected for study due to its unique design. The Kettle River Bridge is a historical steel can...

  3. 下套拱加固石拱桥复合拱圈极限承载力研究%Research on ultimate load -carrying capacity of composite arch ring ofstone arch bridge reinforced by concrete arch -lifted method

    Institute of Scientific and Technical Information of China (English)

    孙潮; 刘明; 陈宝春; 吴庆雄

    2012-01-01

    The composite arch ring formed by soffitting method for stone arch consists four materials, i.e. , stone, mortar, concrete and steel bars. It is a secondary loaded structure, so its behavior is complicated. A finite element method (FEM) to calculate the ultimate load -carrying capacity of the composite arch ring is proposed by using both smeared model and discrete model. The computing results from FEM agrees well with the test results, which indicates that the behavior of the composite arch ring can be depicted well by the proposed FEM. Analysis of a real engineering have been done by using this FEM. Analysis results shows that under the half span distributed load and quarter point load, the failure mode of the composite arch ring is a four - hinges mechanism. The load reaches 77.9% of the ultimate load when the second hinge appears. Ultimate load - carrying capacity decreases with the increase of the ratio of concentrated live load to the total live load, also increases with the increase of the thickness of reinforcement layer and reinforcement ratio. The concrete strength has a little influence on the ultimate load - carrying capacity of composite arch ring, so high strength concrete is not necessary to be adopted in this method.%下套拱加固石拱桥形成的复合拱圈由石块、砂浆、混凝土和钢筋四种材料组成,而且属于二次受力结构,受力复杂.采用分离模型和整体连续体模型相结合的方法,提出复合拱圈的极限承载力有限元计算方法.有限元计算结果与试验结果吻合良好,表明有限元计算方法能够反映复合拱圈的受力性能.应用该方法,对某实桥进行了分析,结果表明,复合拱圈在半跨均布活载和L/4集中活载联合作用下的破坏模式为四铰破坏,第二个铰出现时荷载已达极限荷载的77.9%.复合拱圈的极限承载力随着集中活载占总活载的比例的增大而减小,随加固层厚度和配筋率的增大而增大.

  4. Research on elastic-plastic constitutive relation of stone arch bridge reinforced by composite main arch circle method%复合主拱圈加固石拱桥弹塑性本构关系研究

    Institute of Scientific and Technical Information of China (English)

    乔文靖; 宋一凡; 陈书生

    2013-01-01

    根据复合主拱圈加固石拱桥时截面以承受轴力为主,弯矩较小的受力特点,基于原拱圈和加固层共同工作、协调变形原理,针对加固后的石拱桥,推导出适合有限元分析的混凝土与砌体理想弹塑性复合材料的本构关系.对某复合主拱圈加固的石拱桥应用推导的本构关系,采用有限元软件ANSYS建立了数值分析模型,并对该本构关系进行校核检验.结果表明:采用混凝土与砌体理想弹塑性复合材料非线性计算结果和混凝土与砌体分开的两种材料非线性计算结果非常接近,复合材料非线性的计算值比两种材料非线性的计算值小,轴力小3% ~5%,弯矩小7%~8%.给出的混凝土和砌体的理想弹塑性本构关系在复合主拱圈加固石拱桥时有足够的可靠性,可供同类桥梁结构分析应用.%Because all sections of stone arch bridge reinforced by composite main arch circle method bear axial forces and only bear very small bending moment, the constitutive relation of an ideal elastic-plastic structure of concrete and masonry, which can be applied to finite element analysis is deduced based on the theory that original arch and reinforced layer can work together and coordinate deformation. This constitutive relation is applied to reinforced stone arch bridges, and it is verified by finite element models that are established with ANSYS software. The results show that the calculated nonlinear value of ideal elastic-plastic composite material of concrete and masonry is close to that of concrete and masonry when they are analyzed respectively. The calculated nonlinearity value of the composite material is smaller than that of the two materials: axis force can be reduced by 3% to 5%, and bending moment can be reduced by 7% to 8%. The constitutive relation of ideal elastic-plastic composite material of concrete and masonry is reliable, and can be applicable in the analysis of the same kind of bridge

  5. Comprehensive Construction Technology for All Kinds of Arch Bridges Demolition on Navigable Channel%通航河道各类拱桥拆除综合施工技术研究

    Institute of Scientific and Technical Information of China (English)

    张广义

    2016-01-01

    基于航道整治过程中老桥改建工程,介绍通航河道各类拱桥老桥拆除施工技术,着重说明不同拱桥结构类型、不同航道等级以及不同作业环境下老桥拆除施工技术的应用。通过分析上承式、中承式和下承式拱桥拆除施工中的关键工序和安全控制措施,并应用空间有限元分析程序,解决了通航河道拱桥拆除施工中的各项难题,形成了完整的拱桥拆除综合施工技术。%Based on the bridge rebuilding project during waterway regulation process,this paper makes a brief introduction of the construction technology of all kinds of old arch bridges demolition on navigable channel,emphasizes the application of old bridge demolition construction technology under different kinds of arch bridges structure,different channel levels and different working environment.Through the analysis of the key working procedure of construction and safety control meas-ures of deck-type,half through and through arch bridge,and the application of the space finite element analysis program,it solves the difficult problems during the construction of arch bridge demolition on navigable channel,and forms a compre-hensive construction technology for arch bridge demolition.

  6. 钢管混凝土系杆拱桥施工监控%The Construction Monitoring of Tied Concrete-filled Steel Tubular Arch Bridges

    Institute of Scientific and Technical Information of China (English)

    宋维侠; 晋智斌; 沈建华

    2013-01-01

    在钢管混凝土系杆拱桥整个施工过程中施工现场布置了应力和变形监测点,实时监测桥梁结构的实际状态,运用现代控制理论对误差进行识别,调整预测,使桥梁施工状态最大限度地接近理想状态,保证桥梁结构在施工过程中的安全。钢管混凝土系杆拱桥施工监控就施工控制的各阶段较好地控制了施工中的结构应变行为,保证了大桥的顺利施工,为钢管混凝土系杆拱桥的安全施工提供了可靠依据。%Bymeansofsettingupstressanddeformationmonitoringpointsintheconstructionsitefortheconstructionprocessofconcrete-filled steeltubulararchbridgeandmonitoringtheactualstateofthebridgestructureinrealtime,coupledwiththeerrorsidentification,adjustment and prediction based on modern control theory. It is feasible to achieve rational complete bridge state and to ensure the safety of constructing bridge. In order to provide the theory basis for the smooth and safe construction of the concrete-filled steel tubular arch bridge, it has been dis-cussed on how to scientifically monitor the stress and deformation in different construction procedures.

  7. Monolithic Lithium Disilicate Full-Contour Crowns Bonded on CAD/CAM Zirconia Complete-Arch Implant Bridges With 3 to 5 Years of Follow-Up.

    Science.gov (United States)

    Pozzi, Alessandro; Tallarico, Marco; Barlattani, Alberto

    2015-08-01

    This study was carried on to assess the clinical performance of a novel restorative concept consisting in single monolithic lithium disilicate full-contour crowns bonded on computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia complete-arch implant bridges, to overcome the drawbacks related to the chipping of porcelain fused to zirconia restorations. Sixteen patients received 18 implant-supported hybrid screw-cement-retained complete-arch restorations, consisting of single monolithic lithium disilicate full-contour crowns bonded on CAD/CAM zirconia frameworks. The restorations were supported by 4-8 implants. All patients were followed up for at least 3 years on function (range 36 to 60 months, mean 49.3 months). Clinical controls were scheduled every 4 months. The outcomes were implant and prosthetic survival and success rates, any complications, patient satisfaction, and soft tissue parameters. No dropouts occurred. The overall implant and prosthesis survival rates were 100%. One of 18 restorations (1 of 236 dental units) showed a chip-off fracture of the veneering ceramic that was polished intraorally without any additional treatment, scoring a cumulative prosthetic success rate of 100%, according to the California Dental Association index. All patients were functionally and esthetically highly satisfied with their restorations. Successful soft tissue parameters were found around all implants. Single monolithic lithium disilicate full-contour crowns, bonded on CAD/CAM screw-retained complete-arch zirconia frameworks, showed favorable preliminary outcomes with medium-term follow-up. However, randomized controlled studies of this technique are required for further conclusive recommendations.

  8. Discussion on Yun-Gui Railway Nanpanjiang Grand CFST Arch Bridge Construction Technology%云桂铁路南盘江特大劲性混凝土拱桥施工技术探讨

    Institute of Scientific and Technical Information of China (English)

    冯丛

    2012-01-01

    The paper, taking Yun-Gui Railway Nanpanjiang Grand CFST Arch Bridge as research object, and referring to construction technology of domestic and international long-span deck CFST arch bridges, discusses the 416 m deck CFST arch construction method of the Nanpanjiang Grand CFST Arch Bridge, and then decides the construction plan, technical difficulties and countermeasures, which can offer reference for bridge construction under the same conditions.%以云桂铁路南盘江特大劲性混凝土拱桥为研究对象,参考国内外大跨度上承式劲性混凝土拱桥施工技术,对南盘江特大劲性混凝土拱桥的416 m上承式劲性混凝土拱的施工方法进行探讨,确定施工方案、研究技术难点及相应施工工艺,可为同类条件桥梁施工提供借鉴。

  9. Influence of Void on Stress of Concrete Filled Steel Tubular Arch Bridge%脱空对钢管混凝土拱桥受力的影响分析

    Institute of Scientific and Technical Information of China (English)

    刘龙

    2014-01-01

    Effect of void on the stress characteristics of concrete filled steel tubular arch bridge relates pa-rameters of arch bridge, such as void ratio, steel ratio, truss higher parameters, and so on.Using finite ele-ment analysis method, the article analyzes the state of concrete filled steel tubular arch bridge in void con-dition, and get result about the effect of void on different parameters of concrete filled steel tubular arch bridge, such as stiffness, stability and dynamic characteristics. It will provide reference on theory for relat-ed design in future.%脱空对钢管混凝土拱桥受力特性的影响与拱桥的脱空率、含钢率、桁高等参数有关。采用有限元分析方法对脱空状态下的钢管混凝土拱桥状态进行了具体分析,得到脱空对不同拱桥参数如刚度、稳定性及动力特性等的影响结果,为今后钢管混凝土拱桥的设计提供一定的理论参考。

  10. 上承式拱梁组合桥设计%Design of combined deck type arch bridge

    Institute of Scientific and Technical Information of China (English)

    严国香

    2012-01-01

    结合某桥的工程地理位置及沿河景观要求,对该桥的结构设计特点、构造与施工要点等进行了简要介绍,目前该桥运营情况良好,并取得了一定的经济、社会效益,为同类型桥梁施工积累宝贵经验。%This paper synthesized the engineering geographic location and river landscape requirements of a bridge,simply introduced the structure design features,structure and construction key points of this bridge,present the bridge was operating in good condition,and achieved certain economic,social effect,accumulated valuable experience for the same type bridge construction.

  11. 摩擦摆支座在钢管混凝土拱桥中减震效果研究%Effect of friction pendulum bearings on vibration damping of concrete-filled steel tubular arch bridge

    Institute of Scientific and Technical Information of China (English)

    黄清云; 汪甲; 张克

    2016-01-01

    The effect of friction pendulum vibration isolation and damping bearings on the vibration damping of simply supported arch structure of a rigid concrete-filled steel tubular arch bridge was an-alysed.The arch bridge has a span of 120 m with flexible column lower bearing.Finite element model MIDAS was employed to simulate the multidimensional artificial seismic wave input to investi-gate the damping effect of the friction pendulum bearing system.The results indicate that the friction pendulum bearing system is effective in the vibration damping of the large span concrete filled steel tubular arch bridge.%以跨度为120 m的刚性拱肋柔性系杆的下承式钢管混凝土拱桥为分析模型,利用摩擦摆减震隔震支座对简支体系的桥跨结构进行减震研究,运用MIDAS有限元软件模拟多维人工地震波输入以检验摩擦摆系统的减震效果。分析结果证明了在大跨度钢管混凝土拱桥中应用摩擦摆隔震支座系统的有效性。

  12. 某异型系杆拱桥空间力学特性分析%Analysis of Spatial Mechanical Properties of an Irregular-Shape Tied Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    肖雄杰

    2012-01-01

    为研究斜吊杆异型系杆拱桥的空间力学特性,以某异型系杆拱桥为研究对象,采用MIDAS Civil建立该桥空间有限元模型,分析其在施工和使用阶段的静、动力特性及结构稳定性.分析结果表明:该桥斜吊杆附加应力对拱肋影响较大,全桥纵、横梁框架体系整体刚度较大,拱肋挠度对整体降温比较敏感,使用阶段各吊杆应力幅比较均匀,为50 MPa左右;拱肋侧倾刚度较小,拱肋刚度对全桥刚度贡献较大,各阶段稳定系数均较高;吊杆调索对全桥应力水平有较大影响,施工中应予注意.%To study the spatial mechanical properties of irregular-shape tied arch bridges with inclined hangers, a tied arch bridge of the same type was taken as the research object, the MIDAS Civil was used to set up the spatial finite element model for the bridge, the static, dynamic prop-erties and structural stability of the bridge at construction and service stages were analyzed. The results of the analysis indicate that the impact of additional stress of the inclined hangers on the arch ribs is great. The global rigidity of the stringer and cross beam frame system of the whole bridge is considerable. The deflection of the arch ribs is sensitive to temperature fall. The stress amplitude of the hangers at service stage is uniform and is about 50 Mpa. The lateral inclination rigidity of the arch ribs is little, the contribution of the rigidity of the arch ribs to the rigidity of the whole bridge is great and the stability factors of various stages are high. The adjustment of the hanger cables has considerable impact on the stress levels of the whole bridge, to which atten-tion should be paid in the process of construction.

  13. 钢管混凝土拱桥桥面铺装动力学特性研究%Research on Dynamics Characteristics of Deck Pavement of Concrete-Filled Steel Tube Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    杨咏梅; 庄月明

    2011-01-01

    首先,建立了千岛湖钢管混凝土拱桥的3D有限元模型.通过有限元计算,得到了该钢管混凝土拱桥前8阶的自振频率和自振振型.同时,计算了该钢管混凝土拱桥的水平自振基频与竖向自振基频.接着,选用移动恒载研究车辆荷载作用下的钢管混凝土拱桥桥面铺装结构动力学特性.计算得到该钢管混凝土拱桥的共振速度并分析了桥梁共振响应的可能性.计算了不同车速下跨中节点的竖向最大位移与纵向拉应力,并进一步计算了冲击系数,提出了钢管混凝土拱桥的荷载冲击系数参考值.最后,考虑施工荷载,计算了梁底最大拉应力与最大剪应力,分析了Dynapac CC522型振动压路机施工时对桥梁结构的影响.%First of all, finite element 3D model of the concrete-filled steel tube arch bridge above Qian-dao Lake is established. By calculation of finite element method, the initial eight stages auto-oscillation frequency and mode of the concrete-filled steel tube arch bridge are acquired. Meanwhile, horizontal and vertical auto-oscillation fundamental frequency of the concrete-filled steel tube arch bridge is calculated. Secondly, moving constant load is used to research the dynamics characteristics of deck pavement of the concrete-filled steel tube arch bridge. Resonance velocity of the concrete-filled steel tube arch bridge above Qiandao Lake is computed to analyze the probability of bridge resonance. The maximum vertical displacement and longitudinal tensile stress of mid-span node under different vehicle speeds are calculated. Furthermore, impact coefficient reference value of the concrete-filled steel tube arch bridge is put forward. Finally, considering construction loads, the maximum tensile stress and shearing stress of beam bottom are calculated to analyze the influence of construction exploiting "Dynapac CC522" vibratory roller.

  14. 大跨度系杆拱桥荷载试验方案与计算分析%Loading Test and Calculation Analysis for Tied Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    李凯; 马虎

    2013-01-01

    This paper is about loading test and calculation analysis for tied arch bridge. Firstly, the principal of loading test is introduced briefly; And then, specific methods on static and dynamic tests are stated;Finally, preliminary analysis about static and dynamic test is conducted by using FEA software-Mi-das Civil. Combined specific test results, the information of bearing capacity, stiffness and cracks can be obtained. There-fore, the healthy evaluation of this kind of bridges is clear. This paper provides the basis for healthy evaluation of the same kind of bridges.%本文对大跨系杆拱桥荷载试验方案及其计算进行了分析。首先,对桥梁荷载试验原理做了简要介绍,又以某大跨系杆拱桥为依托,对具体的静载试验和动载试验具体方案做了阐述;最后,采用Midas Civil 有限元计算软件对静载试验及动载试验相关指标进行了初步分析。结合具体的试验结果,即可实现对桥梁承载力、裂缝、刚度及动力特性的评定。本文为同类桥梁的评定提供了依据,具有一定的工程实践意义。

  15. Design of Half-through Anomalistic Arch Bridge on Changsha-Kunming Passenger-dedicated Line%长昆客运专线铁路中承式异型拱桥设计研究

    Institute of Scientific and Technical Information of China (English)

    施威; 孙大斌

    2015-01-01

    为解决长昆客运专线斜跨潭韶高速公路的问题,通过桥式方案比选,结构构造优化,结构静力、动力计算分析,设计研究出拱肋沿桥轴线非对称错位布置、吊杆扇形布设、无风撑拱肋的中承式斜置拱桥。该桥已投入实际运营,应用良好。%To resolve the problem in design to allow Changsha-Kunming passenger dedicated railway to cross over Xiangtan-Shaoshan highway, this paper, on the basis of bridge scheme comparison, construction structure optimization, calculation and analysis of structural statistics and dynamics, comes to the conclusion that the half-through anomalistic arch bridge is recommended and arranged unsymmetrically and misplaced with its arch ribs along the bridge axial line, with its suspenders placed in fan-shape and its arch ribs without wind bracing. This bridge has been put into use with good results.

  16. 多跨连孔双曲拱桥地震反应分析%Seismic response analysis of multi-span continuous hole and double-curved arch bridge

    Institute of Scientific and Technical Information of China (English)

    张云; 周晓蓉; 燕柳斌

    2012-01-01

    To take certain multi-span continuous hole and double-curved arch bridge as an example,build a space beam finite element model of double-curved arch bridge and choose three natural seismic spectrums to time-history analysis,contrast the analysis results under the action of E1 earthquake and the response spectrum analysis results under the same conditions,analyze response of the bridge under the action of E2 earthquake,it obtains beneficial conclusions.As a result,it has laid a foundation for seismic response analysis of multiple-span and continuous hole and double-curved arch bridge.%以某多跨连孔双曲拱桥为例,建立双曲拱桥空间梁单元有限元模型,选择3条天然地震波及1条人工波进行时程分析;对比其在E1地震作用下的分析结果与相同条件下的反应谱分析结果情况,并分析桥梁在E2地震作用下的反应,得出有益结论,从而为多跨连孔双曲拱桥地震反应分析研究奠定基础。

  17. 某双曲拱桥的动静力测试及承载能力评估%The Dynamic and Static Test and Capacity Evaluation on a Double Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    杨勇; 刘能文; 金晶; 李儒

    2012-01-01

    Taking a double arch bridge as the evaluation example, based on the summarization of several finite element discrete methods, in combination with the structure type of double arch bridge, the simulation method combining beam-plate was pointed out in this paper, and finite element model for double arch bridges was established by using large general finite element software ANSYS. At the same time, dynamic load and the static load test method for double arch bridges were elaborated, including using equivalent load method to determine load vehicle, step loading under different conditions, the layout of measuring points in dynamic and static test. According to the comparative analysis between finite element analysis results and dynamic and static test results, the structure performance and the current situation can be obtained. The results show that the correct calculation model is the key of the bearing capacity evaluation for double arch bridges. And the combination of the finite element method of beam-plate method and structure form of double arch bridges is an effective method for space structure analysis of double arch bridges. Using the combination of finite element theory analysis and dynamic and static load test method can comprehensively evaluate the bearing capacity of double arch bridges, which can provide the reference for the calculation analysis and bearing capacity evaluation for the same kind of bridges.%本文以某双曲拱桥的承载力评估为例,在总结几种有限元模型离散方法的基础上,结合双曲拱桥的结构形式,提出采用梁板结合的模拟方法,用大型通用有限元软件ANSYS进行了双曲拱桥的模型建立.同时,阐述了双曲拱桥的动载及静载试验的试验方法与过程,包括用等代荷载的方法确定荷载车辆、各种工况的分级加载、动载及静载试验测点的布置.依据有限元分析结果与动静力荷载结果的对比分析,对工程实例桥的承载能力进行了评

  18. Comparison of Erection Schemes for Steel Tube Arch of Main Bridge of Huanghe River Bridge on Zhungeer-Shuozhou Railway%准朔铁路黄河特大桥主桥钢管拱架设方案比选

    Institute of Scientific and Technical Information of China (English)

    赵剑发

    2015-01-01

    准朔铁路黄河特大桥主桥为主跨380 m的上承式钢管混凝土拱桥,主拱肋为钢管混凝土主弦杆和箱形钢腹杆组成的空间桁架结构。针对该桥结构特点和施工难点,提出了支架拼装并竖转合龙方案、单拱肋单元吊装与双拱肋单元整体吊装的“缆扣法”施工方案,通过技术可行性、经济性、安全性等方面的比选,采用单拱肋和双拱肋单元整体吊装相结合的“缆扣法”施工方案。重量超过缆索吊设计吊重的节段采用单拱肋分别吊装两侧的单肢拱肋,安装K撑和横撑,在空中形成设计节段;其余节段在拼装场形成设计节段,整体运输到缆索吊下方,整体吊装后与前一节段在空中对接,然后扣索,依次形成半拱,最后完成合龙,并灌注钢管混凝土。%The main bridge of the Huanghe River Bridge on Zhungeer‐Shuozhou Railway is a concrete‐filled steel tube (CFST) deck arch bridge with a main span of 380 m .The main arch ribs of the bridge are the spatial truss structure that is composed of the CFST main chords and box steel web members .In the light of the structural features and construction difficulties of the bridge ,the scheme of assembling the main arch ribs on scaffoldings and closing the arch ribs by vertically rotating and the construction scheme of fastening stay method for lifting the single arch rib element and integrally lifting the double arch ribs element were proposed .Through compari‐son of the technical feasibility and the construction cost and safety ,it was determined that the construction scheme of fastening stay method for both lifting the single arch rib element and inte‐grally lifting the double arch ribs element should be adopted .For the arch rib element that was heavier than the designed lifting capacity of the cable crane ,the single arch rib element was lifted only ,the single‐leg rib at each side of the element was respectively lifted and the K

  19. Study of Key Construction Control Technique of Steel Pipe Concrete Arched Bridge%钢管混凝土拱桥施工控制关键技术研究

    Institute of Scientific and Technical Information of China (English)

    王亚超; 张晋

    2009-01-01

    该文结合湖州市奚家庄大桥主拱施工监控方案,运用有限元分析程序和现代测量手段相结合,对钢管混凝土拱桥施工控制中的关键技术进行了深入的研究,可供同类工程施工参考.%Combined with the main arch construction monitoring scheme of Huzhou City Xijiazhuang Bridge, the article uses the finite element analysis program and the modern measuring means to deeply study the key technique in the construction control of steel pipe concrete arched bridge, which can be referred for the similar projects.

  20. 钢管混凝土拱桥吊杆张拉方案比选%Comparison and Selection of Tensioning Scheme for Hangers of Concrete-Filled Steel Tube Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    韩保勤

    2015-01-01

    The main bridge of the Shahe River Bridge on Xingtai‐Fenyang Expressway is a con‐crete‐filled steel tube through arch bridge with a main span of 146 m .The hangers of the bridge were to be constructed by the unstressed state method .To determine the tensioning sequences and to ensure the safety of the tensioning process of the hangers in the construction ,4 types of the hanger tensioning schemes were proposed ,i .e .① the hangers were to be symmetrically tensioned from the arch springs at both ends of the bridge towards the arch crown ;② the hangers to be sym‐metrically tensioned from the arch crown towards the arch springs ;③ the hangers to be symmetri‐cally tensioned from the 1/4 or 3/4 arch ribs towards the arch springs and midspan and ④ the hangers to be tensioned in 3 batches .The software MIDAS Civil was used to set up the finite ele‐ment model for the whole bridge of the bridge ,the simulation calculation was conducted and the tensile forces of the hangers ,displacement of the arch ribs ,core concrete stress of the arch ribs and horizontal thrust of the arch springs of the completed bridge of the 4 tensioning schemes were analyzed .The results of the analysis show that for the scheme 4 ,the tensile forces of the hangers of the completed bridge are closest to the designed tensile forces ,the geometric shapes of the arch ribs are good ,the changing of the concrete compressive stress in the arch rib cross section is uni‐form .No great compressive stress occurs and the influence of the stress on the horizontal thrust of the arch springs is little .In the actual construction ,the scheme 4 is therefore selected .In the scheme ,the hangers of the bridge need not to be adjusted for the second time ,the construction progress of the bridge can be accelerated and the construction cost is also saved .%邢汾高速公路沙河特大桥主桥为主跨146 m的下承式钢管混凝土拱桥,吊杆采用无应力状态法施工。为确定该桥吊

  1. 模糊综合评价法在拱桥健康诊断中的应用研究%The Application of Fuzzy Synthetic Evaluation to Health Diagnosis of Arch Bridges

    Institute of Scientific and Technical Information of China (English)

    焦玲; 喻铮铮

    2011-01-01

    应用基于层次分析法的多级模糊综合评判原理来评价拱桥的工作状态,快捷、准确地了解桥梁的整体安全状况,为其加固、改造提供依据.%It is rapid and exact to make clear the safety situation of arch bridges by using multi-level fuzzy synthetic evaluation which is based on analytic hierarchy process. The result can be referred for the reinforcement and reconstruction of bridges.

  2. The Rotary Construction Technology of Beipanjiang Steel Tube Arch Bridge on Shuibai Railway in Guizhou%贵州水柏铁路北盘江大桥钢管拱转体施工技术

    Institute of Scientific and Technical Information of China (English)

    陶建山; 任旭初; 陈国祥

    2001-01-01

    Beipanjiang Bridge is the first single track deck arch bridge made of steel-tubes, with a spanlength of 236 m. In this paper, the method of factory-manufacture of the elements of steel-tube arch ribs, the welding tecnology in the job-site erection, the rotary structure of the steel-tube arch bridge, the control of the alignement as well as the method of closure with single-hinged rotary technology of the 10 thousand dwt halfarches are introduced.%北盘江大桥是第一座单线铁路上承式钢管拱桥,跨度为236 m。介绍钢管拱工厂单元制造、工地拼装焊接,钢管拱桥的转体结构、线形控制,以及半拱万吨单铰转体合龙的施工技术。

  3. Stability Research of Long Span Half-through Concrete Tied Arch Bridge with Steel Box Section%大跨度中承式钢箱混凝土系杆拱桥稳定性研究

    Institute of Scientific and Technical Information of China (English)

    王明明

    2012-01-01

    Tied-arch continuous-beam bridge is a kind of bridge structure with novel shape and complex stresses. So the stability issues should not be neglected. Spatial analysis model of an actual bridge was established by AN SYS finite element software and the first stability of this bridge under the actions of various kinds of load combinations were analyzed in this article. The secondary stability of this bridge under the actions of geometric nonlinearity, material nonlinearity and dual nonlinearities were also analyzed respectively in this article. The comparing result verifies that the material nonlinear effect on the stability of this bridge is very big. Also general computing methods of arch bridge stability were introduced in this article. The results can provide reference for similar kinds of bridges.%拱式连续梁系杆拱桥是一种造型新颖、受力复杂的桥梁结构,其稳定性问题是不可忽视的.采用ANSYS有限元分析软件对该桥建立计算分析模型,计算该桥梁在各种荷载组合作用下的第一类稳定性.同时计算了该桥在几何、材料以及几何材料双重非线性作用下的第二类稳定性,并将两者的结果作了对比.计算分析结果表明:材料非线性对该桥的稳定性影响很大,同时给出了拱桥稳定性计算的一般性方法,其结果可以为同类型桥梁提供参考.

  4. Design and Construction of Concrete Mixture Ratio for Steel Tube Arch Bridge%钢管拱桥混凝土配合比设计与施工

    Institute of Scientific and Technical Information of China (English)

    孙小伟

    2015-01-01

    西藏昌都澜沧江大桥为大跨度、薄壁钢管混凝土拱桥,其钢管混凝土施工采用泵送顶升法,施工难度大,对混凝土性能要求高。经混凝土配合比设计与优化,制备出满足设计要求的C50微膨胀钢管混凝土,并进行混凝土的拌合物性能、物理力学性能及微观结构分析研究,结果表明,所配制的混凝土不离析、不泌水,坍落度23 cm,混凝土拌和物3 h后的坍落度不小于18 cm,混凝土具有早强、高弹性模量和补偿收缩等性能,完全满足西藏昌都澜沧江大桥钢管混凝土拱桥的工程设计及施工要求。%The Qamdo Lancang river bridge of Tibet is big span, thin-walled concrete-filled steel tube arch bridge. The concrete filled steel tube uses pumping jack-up construction method, which is difficult in construction and has high performance requirements of concrete. Through concrete mixture ratio design and optimization, C50 micro expansive concrete filled steel tube is prepared to meet the design requirements, and the mixture performance physical and mechanical properties and microstructure analysis of concrete are studied. The results show that the mixed concrete has no segregation and no bleeding, 23 cm slump. The slump of concrete mixing content after 3 h is no less than 18 cm. Concrete has high early strength, elastic modulus and shrinkage compensation, fully meeting the engineering design and construction requirements of the bridge.

  5. 浙闽木拱桥类型学研究——以桥板苗系统为视角%Typological study on timber arch bridges in Zhe-Min provinces:with focus on bridge-deck-beam-system

    Institute of Scientific and Technical Information of China (English)

    刘妍

    2011-01-01

    The timber arch bridge in Zhejiang (Zhe) and Fujian (Min) provinces is a unique beamweaving-arch structure, and has a close genetic relationship with the Rainbow Bridge in the famous Song-dynasty painting the scene of the upriver at pure brightness festival ". By a study of typological analysis focusing on the timber structure, it is pointed out in this paper that there is an important distinction between the timber arch bridge in Zhe-Min provinces and the Rainbow Bridge over the Bian River. Throughout the development of the former, the bridge-deck-beam-system has hold a significant role, and should be seen as the third system aside from the first and second systems, viz. the tri-segment arch, and the penta-segment arch. The signification in the bridgedeck-beam-system of timber arch bridge in Zhe-Min provinces includes: functionally, it provides a gentle-sloped floor for the bridge-deck; structurally, it shares the load of the arch, and serves the structural stability; typologically, the method of the combination of the bridge-deck-beam-system and the arch system provides an important factor of depicting the development of the typology of timber bridges. And an essential character of the evolvement of the structure of timber bridges is structure addition and simplification. The simplification and stabilization are the main motivation in the evolvement of timber arch bridges.%浙闽木拱桥独特的编梁拱形结构与汴水虹桥有着密切的关系.对木拱桥结构的类型学分析结果表明,浙闽木拱桥与汴水虹桥的一个重要区别在于,在浙闽木拱桥的发展历程中,桥板苗系统自始至终占有重要的地位,可视作三节苗、五节苗体系之外的第三套体系.浙闽木拱桥桥板苗系统的重要性体现在使用功能上,可保证桥面的平缓;在结构上有效地分担了拱架荷载,并保证结构的稳定;在类型学上,桥板苗系统与编织拱系统的结合方式的多样做法,是探讨木拱桥类型学

  6. Techniques for the Construction of the Arch Ribs of the 113.3 m Bow-String Arch Bridge of the Da-Xi Passenger-Oriented Railway%大西客专113.3m系杆拱桥拱肋施工技术

    Institute of Scientific and Technical Information of China (English)

    赵方刚; 李君君

    2012-01-01

    对大西客专l临汾特大桥113.3m系杆拱桥的主拱肋施工技术进行了介绍,主要包括钢管混凝土主拱肋的制造、安装以及泵送钢管混凝土材料的技术性能指标、施工配合比和顶升施工注意事项等,可为同类桥梁施工提供有益的参考。%Introduced in detail in the paper are the construction techniques for the main arch ribs of the 113.3 m Linfen mega tie arch bridge of the Da-Xi Passengers-oriented Railway, including the manufacturing and installation of the arch ribs, technical targets for pump-conveying concrete materials for steel tubes, construction mixture ratios and points for attention for jacking-up construction techniques, etc. The paper may serve as a useful reference for the construction of other similar bridges.

  7. Biological properties of expandable bridge-arch interbody fusion cage%可膨胀桥拱式椎间融合器的生物学特性

    Institute of Scientific and Technical Information of China (English)

    李莹; 曾昭峰; 张春霖; 严旭

    2014-01-01

    背景:随着脊柱内窥镜等微创技术的发展,各种融合器尤其是膨胀式融合器成为一个研究热点。  目的:介绍自行研制的用于治疗腰椎退行性疾病新的“可膨胀桥拱式椎间融合器”的设计理念和生物学特性。方法:在万方数据库、中国生物医学数据库、中文科技期刊数据库中检索2000年1月至2011年4月有关融合器应用于腰椎退行性疾病的研究文章,关键词为“腰椎退行性疾病,融合器”。分析目前融合器存在的不足,从而提出一种治疗腰椎退行性疾病的新型融合器的构想。  结果与结论:经检索共查到相关文献50篇,排除筛选后纳入34篇进行评价。结合文献检索结果,提示了理想的膨胀式椎间融合器除体积小巧、便于植入等特性外,还应提供足够强度的椎体间支撑及稳定性,可有效防止植入后椎间隙高度丢失。参考以上条件,依据现有技术改良,研制出“可膨胀桥拱式椎间融合器”,十分便于微创植入,稳定性好,防下沉能力强,有很好的应用前景。%BACKGROUND:As spine endoscope and other microinvasive techniques develop, various fusion cages in particular expanded cage become the hot topic. OBJECTIVE:To introduce the design concept and biological characteristics of the novel expandable bridge-arch interbody fusion cage to treat lumbar degenerative disease. METHODS:A computer-based online search of Wanfang, CMB and VIP databases was performed for articles published between January 2000 and April 2011 related to the application of fusion cages in lumbar degenerative disease, with key words “lumbar degenerative disease, interbody fusion cage”. Insufficiency in present cages was analyzed and a novel cage should be designed. RESULTS AND CONCLUSION:A total of 50 relevant literatures were colected, and 27 were included. Results showed that ideal expandable cage should have smal size

  8. Fasting style collapse of a multi-span arch bridge analyze the causes of the box%某多跨空腹式箱形拱桥倒塌成因分析

    Institute of Scientific and Technical Information of China (English)

    饶奇志; 易汉斌; 俞博

    2014-01-01

    In this paper, a box-shaped multi-span arch bridge collapsed fasting accident, for example, ana-lyze the causes of its collapse. First, the bridge collapse accident scene investigation, proved a bit of geologi-cal bridge pier foundation and Conditions; secondly, according to the findings of the arch structure was seized count;moreover, considering the effect of cutting down on the pile bearing capacity of the river bed;the results show that under the riverbed leads to the bridge substructure cut transition from low pile platform for high pile caps, this time the stakes withstand compressive stress is greater than its carrying capacity, the stakes can not bear the weight of the upper structure, leading to the occurrence of arch collapsed.%本文以某多跨空腹式箱形拱桥倒塌事故为例,对其倒塌成因进行了分析。首先,对桥梁倒塌事故现场进行了调查,探明了桥墩基础及桥位地质条件情况;其次,根据调查结果对拱桥结构进行了检算;此外,考虑了河床下切对桩基承载力的影响;分析结果表明,河床下切导致该桥下部结构从低桩承台转变为高桩承台,此时木桩承受的压应力大于其承载能力,木桩已经不能承担上部结构自重的作用,导致拱桥发生倒塌。

  9. Line type control for construction of a basket-style tied bars arch bridge%某提篮式系杆拱桥施工过程的线形控制

    Institute of Scientific and Technical Information of China (English)

    莫增模

    2015-01-01

    以广州市南沙区凤凰三桥为工程背景,针对该桥拱肋拼装后整体吊装,主梁悬臂拼装的特殊施工过程,精确计算其钢箱拱及钢箱梁的三大线形(成桥线形、安装线形、预拼线形),结合具体的施工方法,揭示了三大线形之间的内部转化关系以及各种线形与施工方法的关联性。%This article took the third Fenghuang bridge located in Nansha district Guangzhou as engineering background. After the bridge arch rib assembly for lifting the overall and the main beam cantilever erection of special construction process,calculate accurately line type( line type of sus-pension bridge,alignment line type,preassembly line type)of the steel box arch and steel box girder. Contacting the specific construction methods, reveal internal transformation of the relationship between the three line type and the correlation of a variety of line type and construction methods.

  10. 刚架拱桥斜撑破坏及加固后可靠性分析%Bracing strut failure and its reliability analysis after reinforce in framed arch bridge

    Institute of Scientific and Technical Information of China (English)

    姚良云; 陈燊

    2013-01-01

    Based on the framed arch bridge mechanical behavior and its component structure defects, a solid model of batter brace by means of ANSYS program was established to simulate the reduction of the strength in the wet formed joint of the batter brace, resulting from the descent of the elastic modulus of the concrete. Based on its reliability analysis after reinforce in the framed arch bridge, the the residual service-life of bridge could be predicted.%根据刚架拱桥结构的受力特性和构件本身存在的缺陷,利用斜撑的ANSYS实体模型分析刚架拱桥斜撑的破坏机理,以弹模的降低来模拟斜撑湿接缝处混凝土强度的衰变.研究表明湿接缝处混凝土强度不足是斜撑破坏的主要原因,并对斜撑加固后的可靠性进行分析,预测了斜撑的剩余使用寿命.

  11. 高速铁路下承式钢箱系杆拱结合桥的受力分析%Mechanical analysis of through tied-arch composite bridge on high-speed railway

    Institute of Scientific and Technical Information of China (English)

    周德; 叶梅新; 罗如登

    2009-01-01

    To understand the force-bearing characteristics of through tied-arch composite bridge, a 1?8 scale model was designed and made according to a 140 m steel box tied-arch composite bridge on Wuhan-Guangzhou passenger special railway. Through the model test of 5 load cases including full-bridge uniform load, half-bridge uniform load, full-bridge bias load, half-bridge bias load and overload, the displacements and stresses of the bridge were analyzed. The results show that the displacement of the bridge under half-bridge uniform load is about twice as much as that of the bridge under the full-bridge uniform load. In the case of the bias load, the displacement ratio of the heavy load side to the light load side is less than that of the corresponding loads. The mechanical behavior of the arch ribs, tied-beams and the longitudinal beams in the case of the half-bridge uniform load are worse than those of the full-bridge uniform load. The ends of the first transverse beam are considered as fixed ends while those of the other transverse beams are more like hinge joints during in-plane bending moment. Adopting box beams and larger cross sectional dimensions, the out-of-plane bending problem of the first transverse beam is solved. The rigid hangers bear not only axial force but also bending moments. Owing to its greater bending moment compared with other hangers, special measures in design are needed for the first hanger. The concrete slab mainly withstands axial tensile force and bending moments under vertical load. Its crack width is controlled effectively if high ratio of reinforcement above 3% is used.%为了了解下承式系杆拱结合桥的受力性能,根据武广客运专线某140 m下承式钢箱系杆拱结合桥,设计制作1个比例尺为1-8的全桥试验模型,并对桥梁在全桥均布、半桥均布、全桥偏载、半桥偏载和超载共5种工况进行加载试验和分析.研究结果表明:在均布荷载作用下,半桥加载方式引起的竖向

  12. Numerical simulation and internal force analysis of large span wood arch lounge bridge%大跨木拱廊桥的数值模拟与内力分析

    Institute of Scientific and Technical Information of China (English)

    吕伟荣; 陈智; 王智丰; 梁炜; 周世军; 徐伟芬; 沈明燕

    2014-01-01

    木拱廊桥在中国乃至世界桥梁史上是一种独有的创造,它有着独特的构造特点与结构受力性能。运用Sap2000分析软件,对享有世界第一跨度的浙江丽水九龙国家湿地九龙木拱廊桥进行精细建模,研究廊桥在不同荷载工况下的结构内力和挠度,并对分析结果进行对比。分析结果表明,“三节苗”与“五节苗”在2类工况下均能实现各杆轴力均匀变化,而弯矩、剪力相对较小,实现了拱结构受力机制。%Timber arch lounge bridge is a unique creation in the history of China and even the world, it has a unique structure characteristics and structural performance. By using the ifnite element analysis software Sap2000, a reifned modeling has been carried out, for Jiulong Wood Arch Lounge Bridge in Zhejiang Lishui Jiulong National Wetland, which enjoys a worldwide reputation as a ifrst long-span bridge. The structural internal force and deflection under different load conditions were measured and studied. The results show that“Three bar”and“ifve bar”under two kinds of working conditions can both realize the uniform axial force changes, while the bending moment, shear force were relatively small, thus realizing the mechanism of arch structure.

  13. Construction Monitoring and Control of a Long Span CFST Basket Handle Tied Arch Bridge on High-Speed Railway%高速铁路大跨钢管混凝土提篮式拱桥施工监控

    Institute of Scientific and Technical Information of China (English)

    王君; 杨振伟; 王高彦

    2011-01-01

    To ensure that the geometric shape, stress and internal force of long span concrete-filled steel tube (CFST) basket handle tied arch bridge on high-speed railway can meet their requirements, the 128-m span CFST through basket handle tied arch bridge of Nielson system on Beijing-Shanghai High-Speed Railway spanning Shanghai-Nanjing Expressway was cited as an example. In accordance with the finite element analysis theory, the large scale software MIDAS Civil was used to set up the spatial model and to conduct the corresponding theoretic analysis, and the geometric shapes, stress and internal forces of the tie beams, arch ribs and hangers of the bridge were monitored and controlled. The results reveal that the settlement amount of the tie beams at the early construction stage is little. The settlement amount of the arch ribs at the construction stage after removal of temporary supports of the arch ribs is close to the theoretic valuesand the influence of the settlement amount on the global geometric shape of the bridge is not great. The changing tendencies of the stress measured from each cross section of the tie beams and arch ribs are coincident with the theoretic values and the tie beams and arch ribs are in the range of safety. The relative differences between the measured and target cable forces of the hangers are within +5% and the cable forces can meet the design requirements.%为确保高速铁路大跨度混凝土提篮式拱桥的线形、应力及内力满足要求,以京沪高铁跨沪宁高速公路128m下承式尼尔森体系钢管混凝土提篮式系杆拱桥为例,根据有限元分析理论,采用大型空间有限元分析软件MIDAS Civil建立空间模型进行理论分析,对系梁、拱肋、吊杆进行线形、应力及索力监控.结果显示,系梁在前期施工期间沉降量较小,拆除拱肋临时支架以后的施工阶段中拱肋沉降量与理论计算值较接近,对整体线形影响不大;系梁和拱肋各应力测试截面

  14. Analysis of Mechanical Behavior and Stability of CFST Tied Arch Bridge in Construction Process%钢管混凝土系杆拱桥施工中受力性能及稳定性分析

    Institute of Scientific and Technical Information of China (English)

    陈钒; 王建欣; 王江宇; 韩大勇

    2012-01-01

    To provide the theoretic bases for the construction monitoring and control of concrete-filled steel tube (CFST) tied arch bridge, the Yaowan Water Channel Highway Bridge in Nanyang City of the South-to-North Water Diversion Project was cited as an example, the finite element software was used to set up the three-dimensional model for the whole bridge of the bridge, the internal forces and deformation history of the bridge in the whole construction process and the force conditions of the scaffoldings for concreting of the tie beams were analyzed in detailed consideration of the various factors of the concreting sequences, concrete creep effect, hanger tensioning sequences and multi-time tensioning of the hangers. The results of the analysis show that the stress of the arch rib steel tubes and the concrete in the tubes in the construction process can meet the relevant requirements in the codes. The compressive stress of the concrete in the different branch steel tubes is related to the concreting sequences. The creep of the concrete in the tubes can cause the stress redistribution in the sections of the CFST and the scaffoldings for concreting of the arch ribs can meet the requirements of global and local stability.%为给钢管混凝土系杆拱桥施工监控提供理论依据,以南水北调工程南阳市姚湾跨渠公路桥为背景,采用有限元软件建立全桥三维空间模型,详细考虑混凝土灌注次序、混凝土徐变效应、吊杆张拉次序、系梁多次张拉等环节,对结构施工全过程的内力和变形历程及系梁浇筑过程中支架受力进行分析.结果表明,施工过程中拱肋钢管及管内混凝土应力满足规范要求;各分支钢管中混凝土的压应力与混凝土灌注次序有关;钢管内灌注混凝土的徐变会使钢管混凝土截面发生应力重分布;拱肋支架满足整体稳定性和分支稳定性要求.

  15. Mechanical Behaviors of Key Joints of Concrete-Filled Steel Tube Tied Arch Bridge%钢管混凝土系杆拱桥关键节点的受力行为

    Institute of Scientific and Technical Information of China (English)

    周列茅

    2012-01-01

    为研究钢管混凝土系杆拱桥关键节点的受力行为,以某钢管混凝土系杆拱桥为工程背景,采用有限元方法对其全过程非线性受力行为进行深入分析.首先,建立钢管混凝土拱桥整体模型,对其整体受力行为进行分析,提取系杆拱桥关键节点在设计荷载工况下的最不利内力情况;然后以力边界条件形式施加给节点三维精细有限元模型,对拱脚节点和拱肋吊装节点在设计荷载工况下进行应力分析,探讨2种节点在设计荷载工况下的受力行为;最后,考虑材料非线性行为,采用弧长法对2类节点极限承载力进行分析,探讨其承载非线性行为及安全储备.研究结果表明:这2种节点构造形式在设计荷载工况下均安全可靠,且具有较大的安全储备;拱脚节点区拱肋钢管与系梁上翼缘板相交处存在明显的应力集中现象,该处构造复杂,焊缝多,设计时应重点关注;吊装节点区下弦钢管径向刚度小,采用环向加劲肋加强后,对钢管刚度及承载力均有显著改善.%In order to study the mechanical behaviors of key joints of concrete-filled steel tube (CFST) tied arch bridge, the whole process of nonlinear mechanical behaviors of the key joints was analyzed by finite element method. First, the FEM model of the CFST arch bridge was established to analysis the global mechanical behaviors, and the most unfavorable internal forces of key joints of the tied arch bridge under design loads were extracted. Second, the extracted internal forces were applied to the spatial fine finite element model of joints, and the mechanical behaviors of arch foot joint and arch rib hoisting joint under design loads were analysed to discuss the mechanical behaviors of both kinds of joints under design loads. Finally , considered the nonlinear performance of material, the ultimate bearing capacities of two kinds of joint were calculated by using arc-length method to discuss the

  16. Structure and distribution of arches in shaken hard sphere deposits

    OpenAIRE

    Pugnaloni, Luis A.; Barker, G. C.

    2003-01-01

    We investigate the structure and distribution of arches formed by spherical, hard particles shaken in an external field after they come to rest. Arches (or bridges) are formed during a computer-simulated, non-sequential deposition of the spheres after each shaking cycle. We identify these arches by means of a connectivity criterion and study their structural characteristics and spatial distribution. We find that neither the size distribution nor the shape of the arches is strongly affected by...

  17. 大跨径钢箱提篮拱桥空间稳定性分析%Analysis of Spatial Stability of Long Span Steel Box Basket Handle Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    曹正洲; 冯玉涛; 沈逢俊

    2011-01-01

    随着提篮拱桥跨径的增加,其空间稳定性问题愈发突出,为对大跨径提篮拱桥稳定性以及各稳定性影响因素进行分析,可采用线性屈曲和非线性屈曲2种方法.重庆朝阳复建桥为主跨274 m的中承式钢箱提篮拱桥,通过建立空间有限元模型对结构线弹性稳定及几何非线性稳定进行分析表明:考虑几何非线性因素后结构的1阶稳定系数显著减小,几何非线性对结构稳定性影响显著.对影响结构整体稳定性的因素进行计算分析表明:拱肋内倾角变化对稳定性影响较大,提篮拱内倾角增大,结构的1阶稳定系数增加,但过大的内倾角将导致拱肋扭转失稳;随着矢跨比(宽跨比)的增加,结构的1阶稳定系数增大(减小);横撑、吊杆布置形式对结构稳定性影响较小.%With the increase of span length of basket handle arch bridge, the problem of spatial stability of the bridge becomes even more prominent.For analysis of the stability and the factors having influence on the stability of long span basket handle arch bridge, two methods of the linear buckling analysis and nonlinear buckling analysis may be used.The Chaoyang Rebuilt Bridge in Chongqing is a half-through steel box basket handle arch bridge with a main span 274 m.The linear elastic stability and geometric nonlinear stability of the structure are analyzed, using the spatial finite element models.The results of the analysis show that as the geometric nonlinear factors are taken into account, the 1st order stability coefficient of the structure apparently decreases and the influence of the geometric nonlinearity on the stability of the structure is apparent.The factors having influence on the global stability of the structure are also calculated and analyzed.The results of the calculation show that the influence of variations of the leaning angle of arch rib on the stability is great.As the leaning angle of the basket handle arch increases, the 1st order

  18. Key Technology Research on Stone Arch Bridge Strengthened by Composite Main Arch Circle Method%复合主拱圈加固石拱桥关键技术研究

    Institute of Scientific and Technical Information of China (English)

    周磊; 周建庭; 黄灿; 张力文; 孙伊圣

    2011-01-01

    针对目前规范采用换算截面面积和惯性矩的方法计算石拱桥加固中组合截面承载力无法反应其各部分应力状态的现象,依托实际工程,进行有限元分析.结果显示:加固后原拱圈各截面在承载能力极限状态下的压应力有不同幅度的减小,而新增加固层截面处于较为不利的受拉应力状态,并分析了此加固技术的力学特点.%A finite element analysis relying on actual project was conducted in view of the phenomenon that, the arch reinforcement of composite section bearing capacity calculated by converting section area and moment of inertia cannot reflect to the stress state of each part. The results shows the maximum compressive stress of original arch section have reduced after reinforcement, while the new reinforced layer is under the negative state of tensile stress. It illustrates the mechanical characteristics of the reinforcement technique.

  19. 连续梁拱组合桥梁上部结构施工关键技术研究%On the Key Construction Technology of the Superstructure of Continuous Beam-arch Combination Bridge

    Institute of Scientific and Technical Information of China (English)

    何永泉

    2015-01-01

    随着我国社会水平的提升,经济步伐的推进,我国的交通事业也在这个过程中得到了较大程度的发展。其中,连续梁拱组合桥梁是我国现今桥梁建设中非常重要的一个类型,近年来,已经有很多城市利用该种类型建设桥梁。本文将深入地研究分析连续梁拱组合桥梁上部结构施工关键技术,同时提出相应的政策建议。%With the ascension of social level and the progress of economic, the transportation industry of China also gets a larger degree of development in the process. The combination bridge of continuous beam-arc is a very important type in the current bridge construction of China. In recent years, there are many cities using this type to construct bridges. This paper deeply researches and analyzes the key construction technology of the superstructure of continuous beam-arch combination bridge and puts forward the related policy suggestions.

  20. Dynamic Stability of Long-Span CFST Arch Bridge under Action of Near-Fault Ground Motions%近断层地震作用下大跨CFST拱桥的动力稳定性

    Institute of Scientific and Technical Information of China (English)

    邢帆; 祝兵; 赵灿晖

    2012-01-01

    In order to research the dynamic stability performances of long-span CFST ( concrete-filled steel tubular) arch bridges under the action of near-fault ground motions, an arch bridge with a 132 m main span was taken as the engineering background, and seismic records of the Chi-Chi earthquake in Taiwan, China were set as transverse inputs. The incremental dynamic analysis (IDA) was adopted to determine the critical load of dynamic instability. To increase the efficiency of IDA, the parallel high-performance numerical computing was employed. In addition, the problem of strengthening IDA curve cluster convergence was discussed. The research result shows that near-fault pulse-like ground motions are likely to bring about a great damage and result in nonlinear dynamical limit-load instability, and the corresponding critical load is decreased evidently. Weighted average peak ground acceleration, an new intensity measure, can make the discreteness of IDA curve cluster be improved significandy to avail to reveal the dynamic instability characteristics of CFST arch bridges caused by near-fault ground motions.%为研究大跨度CFST(钢管混凝土)拱桥在近断层地震作用下的动力稳定性能,以主跨132 m的下承式钢管混凝土拱桥为工程背景,以台湾集集地震记录作为横向输入,采用动态增量分析(IDA)方法,对动力失稳临界荷载的确定进行了探讨.为提高IDA的分析效率,采用了高性能数值计算并行处理方法.此外,还讨论了加强IDA曲线簇收敛的问题.结果表明:脉冲型近震可导致非线性极值动力失稳,失稳临界荷载明显降低;采用加权平均加速度峰值作为地震强度指标,能显著改善IDA曲线簇的离散性,有利于揭示近断层地震对钢管混凝土拱桥造成动力失稳的特点.

  1. Study on the Relationship between the Features of the City and the Timber Arch Lounge Bridge in Eastern Fujian as the Background of West Coast of the Taiwan Straits%海西背景下闽东木拱廊桥与城市特色研究

    Institute of Scientific and Technical Information of China (English)

    赵兵; 郑立文; 何细树; 宋云珍

    2012-01-01

    Timber arch lounge bridge mainly located in Eastern Fujian, the Eastern Fujian oities with abundant resource* and cultural traditions in Timber arch lounge bridge need to fully exploit the relationship between the character and resources of the cities. In this paper, for local conditions and regional characteristics, we discussed the relationship between timber arch lounge bridge and the features of the city, and proposed to build a Featured Cities with Timber arch lounge bridge.%福建闽东地区是我国木拱廊桥的主要分布地.在海西发展背景下,有着丰富廊桥资源和悠久廊桥文化的闽东城市需要充分发掘城市资源与城市特色之间的关系.本文就这一问题,针对闽东地区的实际情况和地域特色,论述了闽东木拱廊桥与城市特色的关系,提出建设具有木拱廊桥特色城市的建议.

  2. Study of the longitudinal vehicle distance limit of a tied arch bridge section during the loading test%系杆拱桥拱肋截面荷载试验的纵向车距限值研究

    Institute of Scientific and Technical Information of China (English)

    邱恒雅

    2013-01-01

    Bridge loading test is the most reliable method of determining its bearing capacity. It is Necessary to impose restrictions on the operate miss, in order to make the whole process of loading test more economic, safer and more reliable, and it is more difficult to control the test vehicle arrangement. This thesis takes a tied arch bridge arch-sectional loading test as a case, simulates different load efficiency and using MIDAS software when longitudinal wheelbase changes. The study shows when the longitudinal wheelbase is 2.8-5.0m, the loading efficiencies meet the design requirements. That is to say the layout error of the vehicle distance should not exceed 1.0m during actual operations.%桥梁荷载试验是确定桥梁承载能力的最可靠手段,为了使整个荷载试验过程能够更经济、安全、可靠,必须对现场实际操作误差进行一定的限制,而试验车布置时的纵向轮轴距比较难把握。本文以某系杆拱桥跨中拱肋截面荷载试验为例,在常规设计的基础上,采用MIDAS计算软件模拟计算在不同纵向车轮轴距时的荷载效率的变化情况,从而得到纵向车轮轴距一般在2.8m-5.0m才能保证荷载效率满足设计要求,也就是说实际操作时,车距布置误差不超过1.0m为宜。

  3. 大跨度系杆拱桥减隔震支座参数分析%Parameter Analysis of Long-span Tied-arch Bridge Seismic Isolation Bearing

    Institute of Scientific and Technical Information of China (English)

    刘聪; 李建中

    2013-01-01

    结合一座大跨系杆拱桥实例,分析了不同减隔震支座参数对系杆拱桥减震性能的影响.通过对比发现,支座的球心距越大,减震效果越好.支座的摩擦系数越大,减震效果表现为先减小后变大的趋势,摩擦系数取0.02~0.03时,支座位移和墩台剪力达到最好的减震效果.但是支座参数的不同对承台底剪力总体的影响很小.%This paper takes a large span tied-arch bridge as an example, analyzes the damping performance of the tied-arch bridge with different minus isolation bearing. Through the contrast we find that the bigger of the distance of the two sphericalsurface' s center, the better of the damping effect. While the friction coefficient of the sliding spherical surface gets bigger, the damping effect displays the trend to get first smaller and then bigger. With the friction coefficient at 0.02 ~0.03, there is an optimal effect on the bearing displacement and the sheer force of the bottom section of the pier and the pile caps. But the overall effect is very small for the sheer force of the pile caps.

  4. 系杆拱桥吊杆节点足尺模型承载性能试验研究%Full-Scale Model Test Study of Load-Carrying Behavior of Hanger Joint of Tied Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    桂水荣; 陈水生; 万水

    2013-01-01

    To study if the strength of the anchor head in anchorage zone of the hanger joint of tied arch bridge could meet the load-carrying requirements, the Shengmi Bridge in Nanchang was cited as an example, the full-scale model for the anchorage zone of the hanger joint at arch crown of the bridge was fabricated and the load-carrying capacity of the joint under the action of the de signed load was tested. The spatial finite element model of the anchorage zone was established and the theoretic values of the finite element and the measurement values of the test were comparatively analyzed. The results of the analysis show that the global strength of the double-layer steel socket of the hanger joint can meet the requirements, however, the local compressive strength values of the contact between the stiffening plates and the steel padding plate exceed the allowable values and the stiffening plates should be reinforced. The fabrication accuracy of the model has influence on the proportions of the load shared by the inner layer and outer layer of the steel socket and in the future tests of the similar kind, attention should be paid.%为研究系杆拱桥吊杆节点锚固区锚头强度是否满足受力要求,以南昌生米大桥为研究背景,制作拱顶吊杆节点锚固区的足尺模型,测试在设计荷载作用下吊杆节点承载力,并建立空间有限元模型,对比分析有限元理论值与试验实测值.研究结果表明:双层钢套筒整体强度满足要求,但加劲板与钢垫板接触位置局部抗压强度超过允许值,应对加劲板予以补强.模型试件的制作精度影响内钢管与外钢套筒分担荷载比例,在今后的类似试验过程中应予以重视.

  5. 波司登长江大桥拱肋高性能混凝土设计与试验%Design and test of high-performance arch rib concrete of Bosideng Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    王建军; 李冉; 谢开仲

    2015-01-01

    为得到主跨530 m的中承式钢管混凝土桁架拱桥———波司登长江大桥的拱肋管内C60高性能混凝土混凝土基准配合比,采用密实骨架堆积法进行设计,得到初步配合比为水泥:粉煤灰:砂:石子:水=430:140:701:1041:156。以初步配合比为基础进行制备和试验,优化了胶凝材料体系,硅灰掺量确定为30 kg/m3,经过对混凝土的工作性能和力学性能进行试验检验,最终确定满足大桥使用性能要求的基准配合比为水泥:粉煤灰:硅灰:砂:石:水=430:110:30:701:1041:156。%To determine the reference mixing proportion of the high-performance C60 concrete used in the arch rib of Bosideng Yangtze River Bridge which is a half-through concrete filled steel tube ( CFST) truss arch bridge with a main span of 530 m, the dense frame accumulation method was a-dopted in design, and a preliminary mixing proportion of cement :fly ash( FA) :sand :gravel :water=430:140:701:1041:156 was obtained. Based on the proportion, the concrete was prepared, a test was conducted and the cementitious material system was optimized. The mixing amount of silica fume was determined to be 30 kg/m3 . After the test verification about the working performance and mechanical properties, a reference mixing proportion of the concrete for the bridge was determined as cement :FA :Silica fume(SF) :sand :gravel :water=430:110:30:701:1041:156.

  6. 钢主梁拱桥组合桥面系力学性能分析%MECHANICAL BEHAVIOR ANALYSIS OF COMPOSITE DECK FLOOR OF ARCH BRIDGE WITH STEEL GIRDER

    Institute of Scientific and Technical Information of China (English)

    苏庆田; 李杰; 董冰

    2012-01-01

    钢-混凝土组合结构桥面系近几年开始在拱桥结构中使用,拱桥中组合桥面系受力复杂,其力学性能受钢与混凝土是否连接、是否张拉系杆以及混凝土的浇注顺序等影响.该文采用空间有限元模型,开展了钢主梁拱桥组合桥面系的力学性能研究.研究表明:在钢主梁拱桥结构中混凝土桥面板与钢主梁是否结合对桥面系的整体受力影响甚微,只对桥面系局部位置的混凝土桥面板应力分布有所影响;拱桥中是否安装系杆对桥面系的受力影响较大,而且桥面系的受力与系杆张拉力有密切关系;对于组合桥面系的拱桥采用一次浇筑混凝土桥面板施工方法的桥面系受力要明显优于采用分段浇筑混凝土桥面板的方法.%A steel-concrete composite deck has been used in acrh bridges recently. The mechanism of a composite deck is complex, and was affected by the factors of setting connections between concrete decks and steel girder or not, setting tied bars or not, different deck concrete casting sequences etc. In this paper, mechanical behaviors of a composite deck floor of an arch bridge with steel girders are analyzed by a spatial finite element model. The research results show that whether setting connections between concrete decks and a steel girder or not slightly affects the total mechanical behavior of a deck floor but influents the local stress of the deck; whether setting tied bar affects the deck floor mechanical property greatly and the deck floor stress depends on the tension force of tied bars heavily; as to arch bridge with a composite deck floor, the mechanical behavior of deck floors with casting deck concrete by one time is superior to that of deck floors with casting deck concrete by several times.

  7. Interaction between long -span continuous arch bridge and continuously welded rail%大跨度铁路连续梁-拱组合桥与无缝线路相互作用研究

    Institute of Scientific and Technical Information of China (English)

    戴公连; 刘瑶

    2015-01-01

    To study the interaction between continuous arch bridge and CWR (Continuously Welded Rail), nonlinear bar elements were used to simulate the track -bridge contact.Taking the (82.9 +172 +82.9)m prestressed concrete continuous arch bridge with concrete -filled steel tube as an example,a model was estab-lished by considering arch,derrick,girder,track and neighboring structures.The distributions of the longitudinal forces of CWR and the horizontal forces at the top of piers were systematically analyzed under the actions of ben-ding,braking,thermal effect,wind,shrinkage and creep as well as settlement of bearing.The following conclu-sions are obtained:The temperature load in beam has the greater influence on the track that lies in the middle of the beam than at the end of the beam.Under the action of live load and the braking force,the impact that the load position on the middle of structure is bigger.When strong wind reaches at the speed of 1 kN /m,it is neces-sary to consider the effect of wind load.Creep and shrinkage of concrete with drop in temperature have adverse effects on the rail.Under uneven settlement,the maximum stress in track is 4.9 MPa.When designing the rail track,the above factors should be considered.%研究大跨度铁路连续梁-拱组合桥与无缝线路的相互作用问题,采用非线性弹簧单元模拟梁轨接触,以某桥(82.9+172+82.9)m 连续梁拱桥为例,建立考虑拱肋、横撑、斜撑、吊杆、主梁、轨道以及相邻路基梁轨相互作用模型,系统分析温度荷载、活载、制动力、风荷载、混凝土收缩徐变、支座不均匀沉降作用下连续梁-拱桥无缝线路纵向力的分布规律。研究结果表明:钢轨在跨中位置对梁体升温敏感程度大于梁端位置;单线活载与制动或牵引作用下,钢轨应力在中间加载时比左、右侧加载大;纵向风力达到1 kN /m 以上的地区,须考虑风荷载的影响;同时,混凝土收缩

  8. Not In-Service Railway Arched Bridges and Their Future/ Nieużytkowane Kolejowe Mosty Sklepione I Ich Przyszłość

    Science.gov (United States)

    Juszczyk, Artur; Dankowski, Marek; Wysokowski, Adam

    2015-06-01

    At the turn of the 19th and 20th century, on the areas of today northern and western Poland, the railway infrastructure was developing rapidly. In the late 80's of the previous century many of the railway lines, together with the whole infrastructure including bridges, were being closed down. The example of such practices can be the brick bridge located near Nojewo, Voivodeship wielkopolskie. This article presents the technical parameters of these bridges and their damages as well as ideas for the future development of the railway facilities. Na przełomie XIX i XX wieku na terenie dzisiejszej Polski zachodniej i północnej bardzo intensywnie rozwijana była infrastruktura kolejowa. W efekcie tych działań powstała sieć dróg żelaznych o dużym zagęszczeniu. Pod koniec lat 80-tych ubiegłego stulecia wiele z tych linii było stopniowo zamykanych. Na skutek tych przemian wiele linii oraz obiektów z nimi związanych, w tym obiekty mostowe, zostały pozostawione niekorzystnemu działaniu czasu. Przykładem takich wyłączonych z eksploatacji obiektów są mosty i wiadukty położone w okolicy miejscowości Nojewo. Wspomniane obiekty inżynierskie to ceglane konstrukcje sklepione znajdujące się w ciągu linii kolejowej nr 368 łączącej Szamotuły i Międzychód. W artykule zaprezentowano problem rewitalizacji nieużytkowanych mostów kolejowych na przykładzie obiektów w miejscowości Nojewo w województwie wielkopolskim. Opisano podstawowe parametry techniczne mostów oraz ich uszkodzenia. Przedstawiono propozycje zagospodarowania obiektów.

  9. 大跨度梁拱组合桥的梁轨相互作用设计参数研究%Study of Design Parameters of Beam-Track Interaction of Long Span Hybrid Bridge of Beam and Arch

    Institute of Scientific and Technical Information of China (English)

    戴公连; 刘瑶

    2015-01-01

    为了解梁轨相互作用设计参数对大跨度梁拱组合桥无缝线路的影响,以兰渝线广元段某(82.9+172+82.9) m梁拱组合桥为例,采用ANSYS 软件建立了考虑拱肋—吊杆—主梁—桥墩—桩基—轨道梁轨系统一体化有限元模型,分析了拱肋与吊杆升温、纵向阻力模型、吊杆间距、桥墩高度、制动力率、风荷载等参数对钢轨纵向力的传递规律。结果表明:拱肋升温对钢轨应力的影响较大,计算钢轨伸缩力时,按梁体升温15℃考虑较为安全;梁拱组合桥的梁轨相互作用根据《铁路无缝线路设计规范》计算较为安全;钢轨制动力随固定墩高度的增加而增大,固定墩的墩顶水平力与其墩高基本呈线性递减关系;钢轨应力随吊杆间距的增大而增加;钢轨的最大制动拉、压应力和固定墩的墩顶水平力均与制动力率呈线性关系;风荷载作用下,钢轨应力可达5.8 M Pa以上,风速较大区域需考虑风荷载对钢轨的影响。%To understand the effect of the design parameters of beam‐track interaction on the continuously welded rail on long span hybrid bridge of beam and arch ,a hybrid bridge of beam and arch with span arrangement (82 .9 + 172 + 82 .9 ) m on the Guangyuan section of Lanzhou‐Chongqing Railway was taken as an example ,a finite element model considering the integration of the arch rib -hanger-main beam -pier-pile foundation -beam‐track system was established ,u‐sing the software ANSYS and the effect of the design parameters ,such as the temperature rise in the arch rib and hanger ,longitudinal resistance model ,hanger spacing ,pier height ,braking force ratio and wind load ,on the longitudinal force transmission laws of the steel rail were analyzed . T he results of the analysis show that the effect of the temperature rise in the arch rib on the steel rail stress is great and w hen the steel rail expansion force is calculated

  10. 单跨双曲拱桥的检测与分析%Testing and Analysis of Single-span Double-curve Arched Bridge

    Institute of Scientific and Technical Information of China (English)

    冷冰峰; 马文滢

    2009-01-01

    According to a single-span double-curve bridge constructed in the early stage, the article sets forth in detail how to carry out the safety testing, and puts forward the suitable handling suggestion on the practical background of the project.%该文针对某早期建造的单跨双曲拱桥如何进行安全性检测进行了具体阐述,并根据工程实际背景条件提出了适当的处理建议.

  11. Stress analysis of cable-pylon anchorage zones of an arch-tower cable-stayed bridge%拱塔斜拉桥索塔锚固区应力分析

    Institute of Scientific and Technical Information of China (English)

    郝翠; 王建国; 曹新垒

    2011-01-01

    Taking an arch-tower cable-stayed bridge as the research obi ect, the spatial stress analysis of its cable-pylon anchorage zones is carried out with finite element analysis software ANSYS. Based on the stress analysis of the cable-pylon anchorage zones under different operation conditions, the features of stress distribution of the anchorage zones are summarized and the stress attenuation along the pylon height which is induced by the cable tension or pre-stress is studied. The results obtained can provide useful suggestions for the related designs.%文章以某拱塔斜拉桥为研究对象,运用有限元分析软件ANSYS对其索塔锚固区进行空间应力分析;通过索塔锚固区不同工况下的应力分析,总结了锚固区应力分布特性,并研究了锚固区应力在索力及预应力单独作用时沿高度方向的衰减情况,为相关设计给出了相应的建议.

  12. Research on reasonable side and mid-span ratio of railway long-span continuous beam-arch bridge%大跨度铁路连续梁拱组合桥的合理边中跨比研究

    Institute of Scientific and Technical Information of China (English)

    戴公连; 唐立新; 汪禹

    2015-01-01

    为了解边中跨比对大跨度铁路连续梁拱组合桥受力特性的影响,对目前大跨度铁路梁拱组合桥的边中跨比进行统计,并以兰渝线某(82+172+82)m 连续梁拱组合桥为工程背景,分析边中跨比对该桥内力、变形、支反力、稳定性等方面影响。研究结果表明:大跨度铁路连续梁拱组合桥的合理边中跨比取值为0.46~0.51;边中跨比取值较小时,对结构受力和变形有利,但边支座负反力的出现限制其值应大于0.43;边中跨比的取值对该桥基频和结构稳定性影响较小,随边中跨比由0.447增加到0.506,该桥的稳定安全系数仅增大7.6%。%Span ratio is one of the important design parameters in continuous beam -arch bridge,which directly affects the structural stress reasonably.In order to learn the effects of span ratio on the structural force of railway continuous beam -arch bridge,statistics of span ratio in the current long -span railway beam -arch bridges was analyzed.Taking an (82 +172 +82)m long -span continuous beam -arch bridge on the Lanzhou -Chongqing railway as an example,the effects of span ratio on its internal force,displacement,support reaction,stability and so on were analyzed.The analysis results show that the span ratio of long -span railway continuous beam -arch bridge varies from 0.46 to 0.51.Small span ratio is in favor of structural stress and deformation,but the e-mergence of negative support reaction limits its value should be greater than 0.43.While the contribution of span ratio to natural frequency and structural stability is small.Moreover,it is found that the value of stability factors only increased 7.6% with the span ratio increasing from 0.447 to 0.506.

  13. Analysis of Comparison Among Reinforcing Scheme of Negative Moment Area at Button of Aging and Decreased Arch Bridge%老化损伤石拱桥拱脚负弯矩区加固方案比选分析

    Institute of Scientific and Technical Information of China (English)

    梁啸; 杨军珊; 向波

    2014-01-01

    相比于钢筋混凝土增大截面加固法,CFRP(Carbon Fiber Reinforce Polymer)筋材对老化损伤石拱桥拱脚负弯矩区进行加固具有自重轻、可操作性好、受天气影响小等优点,并充分利用 CFRP 筋材的高强性能。通过在一座服役20 a 并受到损伤的石拱桥加固设计中,对 CFRP 加固的可行性进行了计算分析,并与钢筋混凝土加固方法进行对比,结果表明其在施工运输、工期、自重方面具有明显优势,被优先选用。可为以后的加固设计提供参考。%Reinforcing negative moment area at button of aging and decreased arch bridge with CFRP(Carbon Fiber Reinforce Polymer)bar has advantage of light weight,good operability,and it has little influence on whether,even it can make good use of high strength function of CFRP bar compare to the method of reinforcing by adding area with reinforced concrete.Practicability of reinforcement of CFRP bars was made,as well as and the comparison with the reinforced concrete method.The result showed that reinforced by CFRP bars were advanced in transporting,schedule,and load,of course it was cho-sen.It will supply reference in the future.

  14. Floating-hauling Construction Technique for Large-span,Heavy-weight Leaning-type Tied Arch Bridge%大跨度、大重量斜靠式系杆拱桥浮拖法施工技术研究

    Institute of Scientific and Technical Information of China (English)

    刘强华

    2016-01-01

    基于100 m 跨径云梨桥斜靠式钢箱系杆拱桥工程,介绍浮拖法施工技术在大跨度、大重量偏心斜靠式系杆拱桥施工中的应用,分析系杆拱桥整体浮拖中的关键工序和控制措施,针对云梨桥浮拖过程中的复杂性,应用空间有限元分析程序,进行了关键施工阶段的应力、变形分析,解决了浮拖过程中的稳定性问题。%Based on the project of leaning-type steel-box-tied arch Yunli Bridge with 100 m span,this paper introduces the construction technology of floating-hauling method in large-span and large-weight leaning-type eccentric tied arch bridge construction,then it analyzes the application of the key working procedure in tied arch bridge during overall floating-hauling construction and its control measures.For the complexity in floating-hauling construction of Yunli Bridge,space finite ele-ment analysis program is applied to analyze the stress and deformation in the key construction stage,and it solves the stabil-ity problem in the process of floating-hauling construction.

  15. 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

  16. Aortic arch malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kellenberger, Christian J. [University Children' s Hospital, Department of Diagnostic Imaging, Zuerich (Switzerland)

    2010-06-15

    Although anomalies of the aortic arch and its branches are relatively uncommon malformations, they are often associated with congenital heart disease. Isolated lesions may be clinically significant when the airways are compromised by a vascular ring. In this article, the development and imaging appearance of the aortic arch system and its various malformations are reviewed. (orig.)

  17. 考虑非线性影响的大跨度钢管混凝土拱桥的静风响应分析%Analysis of Static Wind Response of large-span CFST Arch Bridge Considering the Nonlinear Effect

    Institute of Scientific and Technical Information of China (English)

    杨万标; 范存新

    2015-01-01

    以巫峡长江大桥为研究背景,分别研究几何非线性以及几何和材料双重非线性对大桥拱肋在静风荷载作用下内力与位移响应的影响。结果表明:在静风荷载作用下,几何非线性和双重非线性对该桥拱顶的横向位移和扭转位移以及拱肋的面外弯矩影响比较显著,故在进行大跨度钢管混凝土拱桥静风响应分析时不可忽略非线性的影响。%Taking the Wu Gorge Bridge over Yangtse River as the research background, the effect of geometrical nonlinearity and geometric and material double nonlinear to the internal force and displacement response of the arch rib of the bridge under the action of static wind load were studied. The results showed that: under the static wind load, geometry nonlinear and double non-linear have an obvious influence on the lateral displacement, the torsion displacement and the out-of-plane bending moment of the arch. The influence of the nonlinearity can not be ignored in the process of long-span concrete-filled steel tube arch bridge static wind response analysis.

  18. 基于Kriging模型的钢管混凝土连续梁拱桥有限元模型修正%CFST arch/continuous beam bridge FEM model updating based on Kriging model

    Institute of Scientific and Technical Information of China (English)

    胡俊亮; 颜全胜; 郑恒斌; 崔楠楠; 余晓琳

    2014-01-01

    A new method for FEM updating based on Kriging model was developed.The Kriging model is a linear unbiased minimum variance estimation to the unknown data in a region according to some characteristic information of region’s samples which have similar features with the unknown data.This method can obtain higher accuracy predicted results based on a small number of samples.Through a planar truss FEMupdating example,the feasibility and accuracy of the Kriging model were verified.And then the Kriging model was applied to a concrete-filled-steel-tubular (CFST)arch/continuous beam bridge FEM updating and the results were compared with those by the method of genetic algorithm (GA) combined with BP neural network.The analysis results show that the Kriging model needs only a certain amount of measured frequency data for FEM updating.There is no iterative calculation like in the FEM,which will exhaust much calculation time in updating program.This method can accurately predict the modal information outside the active frequency range.The results testify the high computational efficiency,accuracy and feasibility of the method applied in actual engineering.%提出基于Kriging模型的有限元模型修正方法。Kriging模型为据区域内若干信息样品某种特征数据对该区域同类特征未知数作线性无偏、最小方差估计方法,其只用少量样本即可获得较高精度预测结果。用Kriging模型对平面桁架进行有限元模型修正,验证该方法的可行性与准确性;对一连续梁拱桥进行模型修正,并与GA算法、BP神经网络方法模型修正结果比较分析。Kriging模型仅需一定量测量频率信息即可完成模型修正,能避免修正过程中进行有限元模型迭代计算。结果表明,该方法能准确预测有效频率范围(active frequency range)外模态信息,计算效率、精度较高,可用于工程实践。

  19. 圬工拱桥重要性系数分布与倒塌模式相关性研究%Study on correlation between importance coefficient distribution and collapse mode of masonry arch bridge

    Institute of Scientific and Technical Information of China (English)

    彭卫兵; 史贤豪; 刘萌成; 谢波

    2013-01-01

    系统研究基于广义刚度法的构件重要性评价理论在桥梁结构倒塌过程分析中的应用,具体包括以下内容:①推导基于实体单元高斯点应力计算的单元重要性系数计算公式;②用C#和VS.net 2005编程实现单元重要性系数的计算和显示程序的开发;③采用上述程序研究悬臂梁重要性系数的分布以及在重要性系数最大的单元旁进行加固后结构重要性系数的变化;④进一步研究双跨圬工拱桥在试验荷载作用下的重要性系数分布与倒塌模式的关系,并与试验结构进行对比验证.研究结果表明:①在重要性系数最大的单元处进行加固将有效降低最大结构重要性系数,并能使单元重要性系数分布均匀;②结构重要性系数分布局部峰值对应着破坏时可能出现塑性铰的最大个数,且塑性铰出现的顺序由重要性系数局部峰值高的位置向重要性系数局部峰值低的位置传递;③线弹性计算结构重要性系数局部峰值分布位置与考虑结构材料非线性计算结果一致,但方差更大.%The application of the component importance evaluation theory in collapsing process analysis of bridge is studied based on the Generalized Rigidity Method.The research includes the following aspects:① the calculation formula of unit importance coefficient is deduced on the basis of Gauss point stress calculation in solid element,② the calculation of unit importance coefficient and the display program are realized using C # and VS.net 2005,③ the importance coefficient distribution of cantilever beam structure and the changes of importance coefficient after reinforcement in the side of the maximum unit are also discussed,④ the further research will focus on the correlation between importance coefficient distribution and collapse mode of two-span masonry arch bridge under the test load.The results indicate that the reinforcement on the element with maximum coefficient

  20. 津秦客运专线113m简支系杆拱桥平转施工技术%Construction Techniques for Horizontal Rotation of 113-m Span Simply-Supported Tied Arch Bridge on Tianjin-Qinhuangdao Passenger Dedicated Railway

    Institute of Scientific and Technical Information of China (English)

    黄旺明

    2012-01-01

    The Fengnan Bridge on Tianjin-Qinhuangdao Passenger Dedicated Railway crosses both the down line of Tianjin-Shanhaiguan Railway and the link line of Fengxu Railway with its 113-m span simply-supported tied arch bridge. In order not to interfere with the normal operation of the two railway lines under the bridge, the superstructure of the bridge was constructed by the method of completing the whole structure on scaffolding closely off the designed bridge site and integrally horizontally rotating the structure in place to the bridge site. The scaffolding had three parts of the bored pile foundations, steel pipe piles and Bailey truss and was located outside and in parallel to the down line of the Tianjin-Shanhaiguan Railway. The horizontal rotation system for erection of the bridge was composed of the large tonnage spherical hinge bearing, temporary piers and curved slipway beams over the railway lines. After the tied arch bridge became a stable structure system, the bridge was pushed about 33. 53 m along the slipway beams, horizontally rotated about 17?around the center of the spherical hinge bearing and the bridge would cross the existing railway lines to the designed bridge site. At the both ends of the girder of the bridge, the girder was then jacked up or down alternatively to finally seat the bridge on the bearings atop the permanent piers.%津秦客运专线丰南特大桥以113 m简支系杆拱桥同时跨越津山铁路下行线和丰胥联络线,为不影响津山铁路和丰胥联络线的正常运行,该桥上部结构采用异位支架成桥,整体平转至设计桥位的方法施工.异位支架由钻孔桩基础、钢管桩及贝雷梁组成,位于津山线的下行线外侧并与之平行.平转系统由大吨位球形铰支座、临时墩和圆弧形跨线滑道梁组成.拱桥形成稳定的结构体系后,沿圆弧形滑道梁顶推约33.53m,以球形铰支座为中心平转约17°后跨越既有线上空到达设计桥位,在梁体两端交替进

  1. Non-linear Seismic Response of CFST Arch Bridge Considering Foundation-structure Interaction%考虑地基-结构相互作用的钢管混凝土拱桥非线性地震响应

    Institute of Scientific and Technical Information of China (English)

    张波; 李术才; 杨学英; 张峰; 孙国富

    2012-01-01

    The linear and non-linear seismic responses of deck type long span concrete filled steel tube (CFST) arch bridge were analyzed considering foundation-structure interaction. Taking a deck type CFST arch bridge as studying object, a 3D viscoelastic artificial boundary was constructed to simulate the radiation damping and the elasticity recovery capacity of the medium at the far field, and the whole analytic model including the foundation and arch bridge was established. Inputting the Qian'an seismic wave which has amax - 0- 2g amplitude, the linear and nonlinear seismic responses of deck type long-span CFST arch bridge were analyzed considering foundation-structure interaction. The result shows that (1) the nonlinear influences are not ignorable when analyzing the bridge seismic response displacement, the displacement and bending moments My and Mz of main arch ribs of nonlinear seismic response are bigger than those of linear seismic response analysis; (2) the lower chord axial force at springer of nonlinear seismic response analysis is a bit bigger than that of linear seismic response analysis, the lower chord axial force at mid-span of nonlinear seismic response analysis is less than that of linear seismic response analysis.%考虑地基-结构相互作用情况,研究了上承式大跨度钢管混凝土拱桥线性及非线性地震响应.以其上承式钢管混凝土拱桥为工程背景,以三维粘弹性人工边界模拟远场地基的辐射阻尼和弹性恢复性能,建立了包括基岩和上部桥梁的整体分析模型,沿纵桥向输入amax=0.2g迁安地震波,在考虑地基-结构相互作用条件下研究了上承式大跨度钢管混凝土拱桥线性及非线性地震响应.研究表明非线性行为在桥梁进行地震响应位移分析时是不可忽视的,考虑非线性后拱肋地震响应位移计算结果增大,主拱肋部分截面弯矩My、Mz大于线性计算时结果;下弦管轴力在拱脚附近非线

  2. 浅埋式桩基础钢筋混凝土拱桥桥墩防撞安全性评价与加固技术研究%Pier anti-collision safety evaluation of reinforced concrete arch bridge with shallow-buried piles and its strengthening technology research

    Institute of Scientific and Technical Information of China (English)

    吴超; 李德建; 宁夏元; 胡先春

    2013-01-01

    On the background of Yuan River bridge in Wuqiangxi,a method of pier anti-cillision safety evaluation,based on "Highway Bridge Code for Design",was put forward for reinforced concrete arch bridge with shallao-buried piles.On the basis of safety evaluation of Yuan River Bridge pier,a pier strengthening project of Yuan River Bridge in Wuqiangxi was proposed.In order to simulate the interaction of new and old concrete after strengthening of foundation,three-dimensional solid elements were adopted,where two situations of the interface between new and old concrete,i.e.,fully bonded or sliding were taken into account.The feasibility of this pier reinforcement project was studied,which can also provide reference for the similar bridge strengthening engineering.%以五强溪沅水大桥为工程背景,针对浅埋式桩基础钢筋混凝土拱桥,提出基于我国公路桥涵设计规范桥墩防撞安全性评价方法.通过对该桥的桥墩防撞安全性评价提出了相应的桥墩加固方案.采用三维实体单元来模拟基础加固后新老混凝土的共同作用,同时考虑新老混凝土接触面按完全粘结与滑动2种情况建立计算模型,对桥墩防撞加固方案的可行性进行了研究,亦可供同类桥梁加固参考.

  3. Application of Hydraulic-Walking Incremental Launching to Steel Arch Girder Construction of Shen′an Huanghe River Bridge in Lanzhou%兰州深安黄河大桥钢拱梁步履式顶推施工技术

    Institute of Scientific and Technical Information of China (English)

    顾乾岗

    2014-01-01

    The main bridge of Shen′an Huanghe River Bridge in Lanzhou is designed as a bow -string steel arch composite girder bridge with a main span of 156 m .The two arch ribs splay out-ward like a butterfly .The main girder is the steel-concrete composite girder with constant cross section .The main bridges characterized by its heavy weight and long spans ,weighs about 4 000 t after all the components are installed .The main bridge construction is likely to impose impact on the navigation channel and the transportation .Due to these reasons ,the steel arch girder is de-signed to be constructed by the hydraulic-walking incremental launching scheme and by way of multiple-point simultaneous incre mental launching .The specialist hydraulic-walking incremental launching equipment was used to carry out the overall incremental launching construction of the main bridge .During the incremental launching construction ,the truss support structure made of steel tubes was added so as to ensure that the load bearing capacity of the bridge in the incremental launching process could meet the requirements .During the construction ,the technique of incre-mental launching along varying vertical curve was adopted ,the elevation of the temporary piers was optimized and determined by optimizing the preliminary elevation and improving the equip -ment .The construction technique was made better by placing the launching nose on the piers and enhancing applicability of the positioning equipment ,achieving the goal of reducing cost and im-proving safety . The engineering experience proves that the incremental launching technique en-sured the safety of the construction process and the geometrical shape of the completed bridge meets the requirements .%兰州深安黄河大桥主桥为主跨156 m 的下承式蝶形钢拱组合梁桥,主梁为等截面钢-混凝土结合梁,主桥全部拼装完总重约4000 t 。针对主桥重量大、跨度大的特点,以及施工对航道、交通的影

  4. Glossary to ARCH (GARCH)

    DEFF Research Database (Denmark)

    Bollerslev, Tim

    The literature on modeling and forecasting time-varying volatility is ripe with acronyms and abbreviations used to describe the many different parametric models that have been put forth since the original linear ARCH model introduced in the seminal Nobel Prize winning paper by Engle (1982......).  The present paper provides an easy-to-use encyclopedic reference guide to this long list of ARCH acronyms.  In addition to the acronyms associated with specific parametric models, I have also included descriptions of various abbreviations associated with more general statistical procedures and ideas...

  5. Application of space entity the unit model calculations in the testing of the carrying capacity of the stone arch bridge%空间实体单元模型计算在石拱桥承载能力检测试验中的应用

    Institute of Scientific and Technical Information of China (English)

    吴安杰

    2012-01-01

      Currently, domestic and international bridge design software is mostly beam element modeling. In recent years, the space grillage method is the more common.Beam elements for most of the beam bridge analysis relatively simple to apply, but the stone arch bridge analysis is not so ap-ply. Bridge calculation and analysis of the most concern is the the transverse stiffness size and load lateral distribution unit of space entity model can be used to solve this kind of problem. Testing of the carrying capacity of the stone arch bridge engineering background, space solid element modeling in detector design and application of static and dynamic load test calculations, analysis and comparison of the solid element modeling cal-culations,beam element modeling calculations as well as the results of the tests measured.%  目前,国内外桥梁计算设计软件大部分采用梁单元建模。近年来,空间梁格法应用较普遍。梁单元对于大部分梁桥分析比较简单适用,但对于石拱桥分析就不那么适用了。桥梁计算分析中最关注的是结构横向刚度大小和荷载横向分布的问题,空间实体单元模型能很好地解决这类问题。以石拱桥承载能力检测试验为工程背景,介绍了空间实体单元建模在检测方案设计和静、动载试验计算中的应用,并分析对比了实体单元建模计算结果、梁单元建模计算结果以及试验实测结果。

  6. Analysis of the Wind-induced Buffeting Response of Steel Arch Pylon of Single Tower Cable-stayed Bridge During Vertical Rotation Construction%独塔斜拉桥钢拱塔竖转施工风致抖振响应分析

    Institute of Scientific and Technical Information of China (English)

    王向阳; 夏小勇; 韩丽丽

    2016-01-01

    Taking the single tower cable‐stayed bridge on Gaoxin 2nd Road in Wuhan as the research background ,this paper studies the wind‐induced vibration problem during the vertical rotation con‐struction of steel arch pylon of single tower cable‐stayed bridge and analyzes the wind‐induced respon‐ses of steel arch pylon waiting for installation of cables using the finite element analysis software AN‐SYS .Firstly ,the static force coefficients of the arch section for different wind attach angles are calcu‐lated by the combined use of ICEMCFD and FLUENT .By using MATLAB ,linear filtering method is adopted to simulate the fluctuatng wind to calculate the fluctuating wind matrix of key nodes of the steel arch pylon and the time series of wind speed are graphed .The buffeting forces are computed based on the time series of wind speed and then transformed into the time domain .Finally ,wind loads are applied to the FEM model in ANSYS and the wind‐induced vibrations of the steel arch pylon are obtained by the time domain analysis of buffeting using the transient state analysis method .The re‐sults shows that the stability and security of steel arch pylon under wind load can be guaranteed for the one month wating period for the installation of cables .%针对独塔斜拉桥钢拱塔竖转过程中由风荷载引起的振动问题,以武汉市高新二路独塔斜拉桥竖转施工为研究背景,利用有限元分析软件ANSYS对等待挂索的钢拱塔进行风致响应分析。首先运用ICEMCFD和FLUENT结合的方式模拟计算钢拱塔截面在多个风攻角下的静力三分力系数;接着选择线性滤波法进行脉动风模拟,通过MATLAB计算得到钢拱塔关键节点的脉动风速矩阵,并绘制风速时程曲线。根据脉动风速时程曲线计算抖振力的大小并进行时域化处理,在有限元模型上施加风荷载,用瞬态分析法对钢拱塔进行抖振时域分析,获得钢拱塔的振动响应。计算

  7. Comprehensive Real-Time Bridge Health Monitoring System of Tongtai Bridge

    OpenAIRE

    Lei Su-su; Gao Yong-tao; Pan Dan-guang

    2015-01-01

    Tongtai Bridge is the world’s largest suspension curve-girder-skew-arch bridge, which is located in Zhangjiakou, China. The understanding of mechanics characteristics is limited to such complex bridges, so it is necessary to establish reliable health monitoring system to investigate the static and dynamic responses and monitor the safety of the bridge. A comprehensive real-time bridge health monitoring system is establish, which includes four aspects: sensor system, data acquisition and trans...

  8. Burmese Arched Harp

    Science.gov (United States)

    Williamson, Robert M.

    Our knowledge of the history, construction, and tunings of the Burmese arched harp (saùng gauk) comes from a variety of sources. Conversations with master harpists, together with recordings made of their performances between 1960 and 1980, provide richly detailed examples of the effect of Western music on a non-Western musical tradition. Scholars' essays and conference proceedings complement these first-hand accounts, expanding our understanding of Burmese music and musical instruments.

  9. The ARCHES Project

    Science.gov (United States)

    Motch, C.; Arches Consortium

    2015-09-01

    The Astronomical Resource Cross-matching for High Energy Studies (ARCHES) project is a FP7-Space funded programme started in 2013 and involving the Observatoire Astronomique de Strasbourg including the CDS (France), the Leibniz- Institut für Astrophysik Potsdam (Germany), the University of Leicester (UK), the Universidad de Cantabria (IFCA, Spain) and the Instituto Nacional de Tecnica Aeroespacial (Spain). ARCHES will provide the international astronomical community with well-characterised multi-wavelength data in the form of spectral energy distributions (SEDs) for large samples of objects extracted from the 3XMM X-ray catalogue of serendipitous sources. The project develops new tools implementing fully probabilistic simultaneous cross-correlation of several catalogues and a multi-wavelength finder for clusters of galaxies. SEDs are based on an enhanced version of the 3XMM catalogue and on a careful selection of the most relevant multi-wavelength archival catalogues. In order to ensure the largest audience, SEDs will be distributed to the international community through CDS services and through the Virtual Observatory. These enhanced resources are tested in the framework of several science cases. More information may be found at http://www.arches-fp7.eu/

  10. Stability of clogging arches in a silo submitted to vertical vibrations

    Science.gov (United States)

    Lozano, C.; Zuriguel, I.; Garcimartín, A.

    2015-06-01

    We present experimental results on the endurance of arches that block the outlet of a two-dimensional silo when subjected to vertical vibration. In a recent paper [C. Lozano et al., Phys. Rev. Lett. 109, 068001 (2012), 10.1103/PhysRevLett.109.068001], it was shown that the arch resistance against vibrations is determined by the maximum angle among those formed between each particle in the bridge and its two neighbors: the larger the maximum angle is, the weaker the bridge. It has also been reported that the breaking time distribution shows a power-law tail with an exponent that depends on the outlet size, the vibration intensity, and the load [I. Zuriguel et al., Sci. Rep. 4, 7324 (2014), 10.1038/srep07324]. Here we connect these previous works, demonstrating the importance of the maximum angle in the arch on the exponent of the breaking time distribution. Besides, we find that the acceleration needed to break an arch does not depend on the ramp rate of the applied acceleration, but it does depend on the outlet size above which the arch is formed. We also show that high frequencies of vibration reveal a change in the behavior of the arches that endure very long times. These arches have been identified as a subset with special geometrical features. Therefore, arches that cannot be broken by means of a given external excitation might exist.

  11. 基于行波效应的大跨度钢-混凝土组合拱桥地震响应分析%Analysis for Seismic Response of Large-span Steel-concrete Combined Arch Bridges Based on Traveling Wave Effect

    Institute of Scientific and Technical Information of China (English)

    高月琪

    2015-01-01

    研究大跨度结构的地震响应时,有必要考虑地震波的行波效应。针对一种特殊的钢-混凝土组合拱桥进行地震响应研究。以重庆市万县长江大桥为建模依据,使用大型通用有限元软件sap2000建立跨径为420 m的钢-混凝土组合拱桥计算模型,并对该模型多种激励状态进行分析。在一致激励状态下进行几何非线性时程分析,并基于多点激振理论和相对位移法,采用7种不同的时差对计算模型进行行波效应下的地震响应分析。对比研究表明行波效应对大跨度桥梁结构地震响应有很大影响。%In research on seismic response of large -span structures , it is necessary to consider traveling wave effect of seismic wave .This paper researches seismic response in allusion to a special steel -concrete combined arch bridge .With Chongqing Wan County Yangtze River Bridge as the basis for modeling , the paper establishes a computational model of steel -concrete combined arch bridge at a span of 420 m by means of large-scale universal finite element software sap 2000, and analyzes multiple excited states of the model.The paper carries out geometric nonlinear time -history analysis in consistent excited states and seismic response analysis for the computational model under the traveling wave effect by means of 7 different time differences .Comparative research shows that traveling wave effect exhibits great influences on seismic response of structures .

  12. The ARCHES project

    CERN Document Server

    Motch, C; Genova, F; Esteban, F Jiménez-; López, M; Michel, L; Mingo, B; Mints, A; Gómez-Morán, A Nebot; Pineau, F -X; Rosen, S; Sanchez, E; Schwope, A; Solano, E; Watson, M

    2016-01-01

    ARCHES (Astronomical Resource Cross-matching for High Energy Studies) is a FP7-Space funded project whose aim is to provide the international astronomical community with well-characterised multi-wavelength data in the form of spectral energy distributions (SEDs) for large samples of objects extracted from the 3XMM DR5 X-ray catalogue of serendipitous sources. The project has developed new tools implementing fully probabilistic simultaneous cross-correlation of several catalogues for unresolved sources and a multi-wavelength finder for clusters of galaxies for extended sources. These enhanced resources have been tested in the framework of several science cases.

  13. 环境振动下的钢管混凝土拱桥试验与分析%Ambient Vibration Testing and Analysis of Concrete Filled Steel Tube Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    王立宪; 狄生奎; 刘云帅; 花尉攀

    2011-01-01

    环境振动试验是检测大型桥梁结构的主要方法,检测得到的模态参数是判定桥梁健康状况的重要依据.本文基于随机振动理论,从雁滩黄河大桥在环境激励下获得的加速度测试信号中提取高信噪比的响应信号,采用频域峰值法和时域随机子空间法识别得到了该桥的固有频率、阻尼比和振型等模态参数,并与有限元模型计算结果进行了对比,验证了识别结果的可靠性,结果可作为该桥的损伤检测、使用状态评估和健康监测的基础.%Ambient vibration test is the main method of detecting a large bridge structure, Modal parameters is important to determine the health status of the bridge. Based on random vibration theory, as a high signal-to-noise ratio response,virtual response is obtained from the measured acceleration signal of Yantan Yellow River Bridge of Lanzhou under ambient excitation. Yantan Yellow River bridge's modal parameters, such as natural frequency, damping ratio and mode of vibration, are identified by using the peak picking and stochastic subspace identification, and are compared with the finite element model results and verified the reliability of recognition results. The identified dynamic properties can be served as the basis in the finite element model updating, damage detection, condition assessment and health monitoring of the bridge.

  14. Semi- and Nonparametric ARCH Processes

    Directory of Open Access Journals (Sweden)

    Oliver B. Linton

    2011-01-01

    Full Text Available ARCH/GARCH modelling has been successfully applied in empirical finance for many years. This paper surveys the semiparametric and nonparametric methods in univariate and multivariate ARCH/GARCH models. First, we introduce some specific semiparametric models and investigate the semiparametric and nonparametrics estimation techniques applied to: the error density, the functional form of the volatility function, the relationship between mean and variance, long memory processes, locally stationary processes, continuous time processes and multivariate models. The second part of the paper is about the general properties of such processes, including stationary conditions, ergodic conditions and mixing conditions. The last part is on the estimation methods in ARCH/GARCH processes.

  15. Simple Way of Recording Dental Arch Forms

    OpenAIRE

    Gupta, Shreya; Ratre, Ram Kishore; Jain, Sandhya; Chandki, Rita

    2015-01-01

    Like finger prints each individual has a unique dental arch form design. Recording patient’s dental arch form may be required in various fields in dentistry be it longitudinal studies for evaluating growth, forensic dentistry and most importantly in orthodontic practice for fabricating arch wires for individual patients. An easy and practical method to obtain individual arch form for each patient is explained.

  16. Super-light pearl-chain arch vaults

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl; Halding, Philip Skov

    2014-01-01

    are assembled on the erection site by means of post-tensioning and lifted in place in buildings and bridges. The super-light SL-deck element is developed by the company Abeo Ltd and The Technical University of Denmark for plane floor structures in buildings. However, this deck element is designed in such a way...... that it is also applicable as basic elements for super-light pearl-chain vaults. Machines and software have been developed for automatic mass production of the elements, and the first factory has started production in Denmark in 2014 delivering SL-deck elements for a variety of building projects. This means...... that the basic elements have become affordable and arch vaults can now be applied at a very low cost and much cheaper than ever before. The new technology is therefore capable of re-introducing the arch vault in construction. The application of SLdecks means that the advantages of these elements are incorporated...

  17. Theory of Arched Structures Strength, Stability, Vibration

    CERN Document Server

    Karnovsky, Igor A

    2012-01-01

    Theory of Arched Structures: Strength, Stability, Vibration presents detailed procedures for analytical analysis of the strength, stability, and vibration of arched structures of different types, using exact analytical methods of classical structural analysis. The material discussed is divided into four parts. Part I covers stress and strain with a particular emphasis on analysis; Part II discusses stability and gives an in-depth analysis of elastic stability of arches and the role that matrix methods play in the stability of the arches; Part III presents a comprehensive tutorial on dynamics and free vibration of arches, and forced vibration of arches; and Part IV offers a section on special topics which contains a unique discussion of plastic analysis of arches and the optimal design of arches.

  18. 大跨钢桁拱钢-混组合桥面板极限承载力试验%Experiment on Ultimate Bearing Capacity of Steel and Concrete Composite Deck Slab of Long Span Steel Truss Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    卢彭真; 赵人达; 任剑

    2012-01-01

    To assess the ultimate bearing capacity of the steel-concrete composite deck slab subject to highway load, ultimate bearing capacity tests were carried out. According to Saint Venant Principle, by taking the part steel-concrete deck slab in column area with positive and negative bending moments as finite element models of the actual bridge, the study focused on the ultimate bearing capacity of the steel-concrete deck slab in column area with positive and negative bending moments for 2 composite deck slab specimens (model A and model B). The results show that tensile failure has occurred in the concrete slab of model A. The upper and lower flange plates of I beam, web plate and longitudinal reinforcement have not yielded under ultimate load, but steel bottom plate, PBL and lateral reinforcement have yielded before failure. The failure load of model A is 1 750 kN. As for model B, concrete slab has compression failure, PBL has yielded before failure, and the failure load of model B is 2 200 kN. Research results provide reference for design calculation of the ultimate bearing capacity of steel-concrete composite deck slab.%为评估钢一混组合桥面板结构在公路荷栽作用下的极限承载力,对其进行极限承载力性能试验研究。根据圣维南原理,选取正负双向弯矩受力的立柱区部分桥面板作为实桥的有限元分析模型,并试验制作了2个等尺模型试件A和B,用于考察钢一混组合桥面板正负双向弯矩区的极限承载力性能。试验结果表明:模型A混凝土板被拉坏,工.字钢上下翼缘板、腹板以及纵向钢筋始终未屈服,PBL、钢底板以及横向钢筋均在破坏之前屈服,模型A的破坏荷载为1750kN;模型B混凝土板被压坏,PBL在破坏之前屈服,模型B的破坏荷载为2200kN。研究结果可为钢一混组合桥面板极限承栽能力设计计算提供参考。

  19. Experimental behavior of FRP strengthened masonry arches

    OpenAIRE

    Oliveira, Daniel V.; Basílio, Ismael; Lourenço, Paulo B.

    2010-01-01

    This paper deals with the experimental behavior of solid clay brick masonry arches strengthened with glass fiber reinforced polymer composites. Twelve half-scaled segmental masonry arches subjected to a load applied at the quarter span were tested under displacement control up to failure. The arches were built using handmade low strength bricks and a commercial lime-based mortar, trying to mimic ancient structures. Besides reference unreinforced arches, five different strengthening arrangemen...

  20. Comparison of Commercially Available Arch Wires with Normal Dental Arch in a Group of Iranian Population

    OpenAIRE

    Zohreh Hedayati; Farnaz Fakhri; Vahid Moshkel Gosha

    2015-01-01

    Statement of the Problem The stability of orthodontic treatment depends on preserving the patient’s pretreatment arch form and arch size during and after treatment. Purpose This investigation was aimed to study the size and shape of Iranian mandibular dental arch and evaluate the correlation of their average dental arch with commercially available preformed rectangular nickel-titanium arch wires. Materials and Method In this study, 148 subjects were selected among students of Shiraz Universit...

  1. Comparison of Commercially Available Arch Wires with Normal Dental Arch in a Group of Iranian Population

    Directory of Open Access Journals (Sweden)

    Zohreh Hedayati

    2015-06-01

    Full Text Available Statement of the Problem: The stability of orthodontic treatment depends on preserving the patient’s pretreatment arch form and arch size during and after treatment. Purpose: This investigation was aimed to study the size and shape of Iranian mandibular dental arch and evaluate the correlation of their average dental arch with commercially available preformed rectangular nickel-titanium arch wires. Materials and Method: In this study, 148 subjects were selected among students of Shiraz University of Medical Sciences. The inclusion criteria were having Angle class I in molar and canine relationships, and normal growth pattern. Intercanine and intermolar widths were measured after scanning their mandibular dental casts. Three main arch form templates; square, ovoid and tapered (Orthoform TM; 3M, Unitek, CA, USA and 12 commercially available preformed mandibular nickel-titanium arch wires were scanned. Intercanine and intermolar widths of arch wires were compared with dental arch widths of the study samples. Arch width, arch form and the most appropriate arch wire were determined for each cast. Student’s t-test was used to compare arch widths and arch depths of male and female sub-jects. Coefficient of variance was used to determine the variability of indices in the study samples. Results: Most preformed arch wires were wider than the average width of the nor-mal Iranian dental arch. The most frequent arch form in Iranian population was tapered. Inter molar width was the only statistically significant variable between males and females. Conclusion: Variation in available preformed arch wires does not entirely cover the range of diversity of the normal dental arch of our population. Narrow arc

  2. The Arches Cluster Mass Function

    CERN Document Server

    Kim, S S; Kudritzki, R P; Najarro, F; Kim, Sungsoo S.; Figer, Donald F.; Kudritzki, Rolf P.

    2006-01-01

    We have analyzed H and K_s-band images of the Arches cluster obtained using the NIRC2 instrument on Keck with the laser guide star adaptive optics (LGS AO) system. With the help of the LGS AO system, we were able to obtain the deepest ever photometry for this cluster and its neighborhood, and derive the background-subtracted present-day mass function (PDMF) down to 1.3 Msun for the 5 arcsec-9 arcsec annulus of the cluster. We find that the previously reported turnover at 6 Msun is simply due to a local bump in the mass function (MF), and that the MF continues to increase down to our 50 % completeness limit (1.3 Msun) with a power-law exponent of Gamma = -0.91 for the mass range of 1.3 < M/Msun < 50. Our numerical calculations for the evolution of the Arches cluster show that the Gamma values for our annulus increase by 0.1-0.2 during the lifetime of the cluster, and thus suggest that the Arches cluster initially had Gamma of -1.0 ~ -1.1, which is only slightly shallower than the Salpeter value.

  3. 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...

  4. Evaluation of the fit of preformed nickel titanium arch wires on normal occlusion dental arches

    Directory of Open Access Journals (Sweden)

    Rakhn G. Al-Barakati

    2016-01-01

    Conclusions: Using an archwire form with the best fit to the dental arch should produce minimal changes in the dental arch form when NiTi wires are used and require less customization when stainless-steel wires are used.

  5. Tranverse Deck Reinforcement for Use in Tide Mill Bridge

    OpenAIRE

    Bajzek, Sasha N

    2013-01-01

    The objective of the research presented in this thesis was to study and optimize the transverse deck reinforcement for a skewed concrete bridge deck supported by Hybrid Composite Beams (HCB\\'s).  An HCB consists of a Glass Fiber Reinforced Polymer outer shell, a concrete arch, and high strength seven wire steel strands running along the bottom to tie the ends of the concrete arch together.  The remaining space within the shell is filled with foam.  The concrete arch does not need to be cast u...

  6. Tympanic ossicles and pharyngeal arches.

    Science.gov (United States)

    Whyte, J; Cisneros, A; Yus, C; Fraile, J; Obón, J; Vera, A

    2009-02-01

    We have performed a study on 11 human embryos regarding the development of the tympanic ossicles and their relationship with the first pharyngeal arch. After performing measurements to date the embryos and foetuses chronologically, we performed a meticulous dissection of the temporal bones. Subsequently, they were fixed in 10% formol, decalcified with 2% nitric acid, embedded in Paraplast, sectioned in 7-mm sequences and stained with Martin's trichrome technique. In the 21- and 24-mm cranium-raquis (CR) length human embryos, we have observed the head of the malleus and the body of the incus close to Meckel's cartilage, in addition to the handle of the malleus, the long limb of the incus and the stapes. Between them there was a mesenchymal band inside the primordium of the tympanic cavity. In the 27-mm CR embryo, the various components of the malleus and incus were fusing, and in the 30-mm CR embryo the union was complete. From our observations, we can conclude that the malleus and the incus are derived from the first and second pharyngeal arches.

  7. Maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width groups

    Science.gov (United States)

    Shahid, Fazal; Alam, Mohammad Khursheed; Khamis, Mohd Fadhli

    2015-01-01

    Objective: To investigate the maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width (intercanine, interpremolar, and intermolar) groups. Materials and Methods: The calculated sample size was 128 subjects. The crown width/height, arch length, arch perimeter, and arch width of the maxilla and mandible were obtained via digital calliper (Mitutoyo, Japan). A total of 4325 variables were measured. The sex differences in the crown width and height were evaluated. Analysis of variance was applied to evaluate the differences between arch length, arch perimeter, and arch width groups. Results: Males had significantly larger mean values for crown width and height than females (P ≤ 0.05) for maxillary and mandibular arches, both. There were no significant differences observed for the crown width/height ratio in various arch length, arch perimeter, and arch width (intercanine, interpremolar, and intermolar) groups (P ≤ 0.05) in maxilla and mandible, both. Conclusions: Our results indicate sexual disparities in the crown width and height. Crown width and height has no significant relation to various arch length, arch perimeter, and arch width groups of maxilla and mandible. Thus, it may be helpful for orthodontic and prosthodontic case investigations and comprehensive management. PMID:26929686

  8. Techniques for aortic arch endovascular repair.

    Science.gov (United States)

    kHONGKU, Kiattisak; Dias, Nuno; Sonesson, Bjorn; Resch, Timothy

    2016-06-01

    This article reviews endovascular strategies for aortic arch repair. Open repair remains the gold standard particularly for good risk patients. Endovascular treatment potentially offers a less invasive repair. Principles, technical considerations, devices and outcomes of each technique are discussed and summarized. Hybrid repair combines less invasive revascularization options, instead of arch replacement while extending stent-graft into the arch. Outcomes vary with regard to extent of repair and aortic arch pathologies treated. Results of arch chimney and other parallel graft techniques perhaps make it a less preferable choice for elective cases. However, they are very appealing options for urgent or bailout situations. Fenestrated stent-grafting is subjected to many technical challenges in aortic arch due to difficulties in stent-graft orientation and fenestration positioning. In situ fenestration techniques emerge to avoid these problems, but durability of stent-grafts after fenestration and ischemic consequences of temporary carotid arteries coverage raises some concern total arch repair using this technique. Arch branched graft is a new technology. Early outcomes did not meet the expectation; however the results have been improving after its learning curve period. Refining stent-graft technologies and implantation techniques positively impact outcomes of endovascular approaches. PMID:26940011

  9. Pervious concrete fill in Pearl-Chain Bridges: Using small-scale results in full-scale implementation

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Truelsen, R.;

    2016-01-01

    Pearl-Chain Bridge technology is a new prefabricated arch solution for highway bridges. This study investigates the feasibility of pervious concrete as a filling material in Pearl-Chain Bridges. The study is divided into two steps: (1) small-scale tests where the variation in vertical void...

  10. Nonlinear Dynamics of Electrostatically Actuated MEMS Arches

    KAUST Repository

    Al Hennawi, Qais M.

    2015-05-01

    In this thesis, we present theoretical and experimental investigation into the nonlinear statics and dynamics of clamped-clamped in-plane MEMS arches when excited by an electrostatic force. Theoretically, we first solve the equation of motion using a multi- mode Galarkin Reduced Order Model (ROM). We investigate the static response of the arch experimentally where we show several jumps due to the snap-through instability. Experimentally, a case study of in-plane silicon micromachined arch is studied and its mechanical behavior is measured using optical techniques. We develop an algorithm to extract various parameters that are needed to model the arch, such as the induced axial force, the modulus of elasticity, and the initially induced initial rise. After that, we excite the arch by a DC electrostatic force superimposed to an AC harmonic load. A softening spring behavior is observed when the excitation is close to the first resonance frequency due to the quadratic nonlinearity coming from the arch geometry and the electrostatic force. Also, a hardening spring behavior is observed when the excitation is close to the third (second symmetric) resonance frequency due to the cubic nonlinearity coming from mid-plane stretching. Then, we excite the arch by an electric load of two AC frequency components, where we report a combination resonance of the summed type. Agreement is reported among the theoretical and experimental work.

  11. Determinant factors of Yemeni maxillary arch dimensions

    Directory of Open Access Journals (Sweden)

    Nabil Muhsen Al-Zubair

    2015-01-01

    Conclusion: Measurements of palatal depth and relationships of the canines to one another and to other teeth thus had the widest ranges, implying that these dimensions are the strongest determinants of maxillary arch size.

  12. Measurement evaluation and FEM simulation of bridge dynamics

    OpenAIRE

    Andersson, Andreas; Malm, Richard

    2004-01-01

    The aim of this thesis is to analyse the effects of train induced vibrations in a steel Langer beam bridge. A case study of a bridge over the river Ljungan in Ånge has been made by analysing measurements and comparing the results with a finite element model in ABAQUS. The critical details of the bridge are the hangers that are connected to the arches and the main beams. A stabilising system has been made in order to reduce the vibrations which would lead to increased life length of the bridge...

  13. State-of-the-art of long-span bridge engineering in China

    Institute of Scientific and Technical Information of China (English)

    XIANG Haifan; GE Yaojun

    2007-01-01

    This paper introduces the state-of-the-art of long-span bridge engineering in China with emphases on recent long-span bridge projects,bridge deck configuration and material,design codes of long-span bridges and improvement of aerodynamic performance.The recent long-span bridge projects include thirty-eight completed suspension bridges,cable-stayed and arch bridges with a main span over 400 m,and eighteen major bridges are under construction.The bridge deck configuration and material,with prestressed concrete decks,steel-concrete composite decks and steel box decks together with several popular cross-sections,are presented.The third part briefly outlines four design codes,including static and dynamic design for highway long-span bridges,and the recent engineering experiences gained from several aerodynamic vibration control projects of long-span bridges are shared in the last part.

  14. 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.

  15. Comprehensive Real-Time Bridge Health Monitoring System of Tongtai Bridge

    Directory of Open Access Journals (Sweden)

    Lei Su-su

    2015-01-01

    Full Text Available Tongtai Bridge is the world’s largest suspension curve-girder-skew-arch bridge, which is located in Zhangjiakou, China. The understanding of mechanics characteristics is limited to such complex bridges, so it is necessary to establish reliable health monitoring system to investigate the static and dynamic responses and monitor the safety of the bridge. A comprehensive real-time bridge health monitoring system is establish, which includes four aspects: sensor system, data acquisition and transmission system, data processing and control system, structure early warning and security assessment system. The paper systematically describes the system design principles, sensor layout, and monitoring content, then expounds system integration and function of each subsystem.

  16. Experimental Study of Properties of Pervious Concrete used for Bridge Superstructure

    DEFF Research Database (Denmark)

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

    2014-01-01

    -Chain Bridges are a new patented bridge technology consisting of a number of Super-Light Deck elements, which are post-tensioned to create an arch bridge used for example for highways. The present study investigates how pervious concrete can be applied as a stabilizing filling materi-al between the arch...... substructure and the wearing course. One pervious concrete mixture contain-ing air entrainment is designed and tested. The tests include investigations of compaction meth-ods, compressive strength, stiffness, frost resistance and permeability....

  17. Arch Index: An Easier Approach for Arch Height (A Regression Analysis

    Directory of Open Access Journals (Sweden)

    Hironmoy Roy

    2012-04-01

    Full Text Available Background: Arch-height estimation though practiced usually in supine posture; is neither correct nor scientific as referred in literature, which favour for standing x-rays or arch-index as yardstick. In fact the standing x-rays can be excused for being troublesome in busy OPD, but an ink-footprint on simple graph-sheet can be documented, as it is easier, cheaper and requires almost no machineries and expertisation. Objective: So this study aimed to redefine the inter-relationship of the radiological standing arch-heights with the arch-index for correlation and regression so that from the later we can derive the radiographical standing arch-height values indirectly, avoiding the actual maneuver. Methods: The study involved 103 adult subjects attending at a tertiary care hospital of North Bengal. From the standing x-rays of foot, the standing navicular, talar heights were measured, and ‘normalised’ with the foot length. In parallel foot-prints also been obtained for arch-index. Finally variables analysed by SPSS software. Result: The arch-index showed significant negative correlations and simple linear regressions with standing navicular height, standing talar height as well as standing normalised navicular and talar heights analysed in both sexes separately with supporting mathematical equations. Conclusion: To measure the standing arch-height in a busy OPD, it is wise to have the foot-print first. Arch-index once get known, can be put in the equations as derived here, to predict the preferred standing arch-heights in either sex.

  18. 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.

  19. Dental Arch Dimension of Malay Ethnic Group

    Directory of Open Access Journals (Sweden)

    H. A. Mohammad

    2011-01-01

    Full Text Available Problem statement: Many previous studies tried to define and put specific measurements for dental arches dimension in different ethnics groups. However, these studies may be specific to an ethnic group and cannot always be applied to other ethnic types. The aim of this study: is to obtain specific dental arch dimensions for Malaysian Malay ethnic groups and compare between both genders. Approach: Involved clinical examination, collection and analysis of 60 dental cast of Malaysian Malay subjects from pure ethnic group (30 males and 30 females, 20-24 years old. All dental landmarks were located and determined and subsequently measurements had been done according to specific points have been selected. Statistical analysis were done using t-test. Results: Dental arch dimension were established in normal occlusion for Malaysian Malay ethnic group in this study. No significant difference was observed in arch dimensions between male and female of Malaysian Malay. Conclusion: These measurement should be considered during treatment, especially in prosthodontics and orthodontics where arch dimension can be modified appreciably.

  20. Tubular Steel Arch Stabilized by Textile Membranes

    Directory of Open Access Journals (Sweden)

    Ondrej Svoboda

    2016-10-01

    Full Text Available Tubular steel arch supporting textile membrane roofing is investigated experimentally and numerically. The stabilization effects of the textile membrane on in-plane and out-of-plane behavior of the arch is of primary interest. First a model of a large membrane structure tested in laboratory is described. Prestressed membranes of PVC coated polyester fabric Ferrari® Précontraint 702S were used as a currently standard and excellent material. The test arrangement, loading and resulting load/deflection values are presented. The supporting structure consisted of two steel arch tubes, outer at edge of the membrane and inner supporting interior of the membrane roofing. The stability and strength behavior of the inner tube under both symmetrical and asymmetrical loading was monitored and is shown in some details. Second the SOFiSTiK software was employed to analyze the structural behavior in 3D, using geometrically nonlinear analysis with imperfections (GNIA. The numerical analysis, FE mesh sensitivity, the membrane prestressing and common boundary conditions are validated by test results. Finally a parametrical study concerning stability of mid arch with various geometries in a membrane structure with several supporting arches is presented, with recommendations for a practical design.

  1. The fundamental concepts of the limit design of stone arches; La verifica degli archi a conci lapidei

    Energy Technology Data Exchange (ETDEWEB)

    Clemente, Paolo [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1997-07-01

    Stone arches represent one of the most interesting topics in the field of the preservation of historic and monumental structures. The reason of this interest is related to the conservation of ancient structures, which have arrived until our age and to the relatively recent construction, especially railway bridges, of this century. In this paper the fundamental concepts of the limit design of stone arches are discussed. The simple case of funicular arch is first shown. Then the two classical shape are studied, parabolic and circular, subject to dead loads only. Finally, the effects of live loads and seismic loads are analyzed. The numerical analysis were carried out by means of computer codes. The results are plotted in diagrams to be used for the structural check.

  2. Assembly and lifting of Pearl-Chain arches

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Viebæk, N.E.;

    2015-01-01

    Pearl-Chain arches were invented at the Technical University of Denmark in cooporation with the company Abeo A/S. The system uses specially designed, pre-fabricated concrete elements that are post-tensioned together into an arch shape, which is then lifted into place. The arches can be used both ...

  3. Arch Coal focuses on its future

    International Nuclear Information System (INIS)

    Arch Coal, Inc (ACI) has emerged as the second largest US coal producer, with nearly 5000 employees producing 110 million tons of coal per year. The article discusses the company's philosophy, as stated by Steve Leer, President and CEO, and reports interviews with six other senior executives talking about policy on finances, sales, marketing, business development and operations. 8 photos

  4. 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.......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....

  5. Programmevaluierung Bridge

    OpenAIRE

    Warta, Katharina; Good, Barbara; Geyer, Anton

    2009-01-01

    BRIDGE is an initiative funded by the Ministry for Transport, Innovation and Technology (BMVIT) that aims to close the “funding gap” between basic and applied research in stand-alone projects with the primary objective of jointly developing the potential of basic and applied research. BRIDGE acts as an  umbrella structure under which the Austrian Science Fund (FWF) and the  Austrian Research Promotion Agency (FFG) coordinate two thematically open funding programmes: The ...

  6. Design and construction of the Aoba bridge; Aoba ohashi no keikaku to seko

    Energy Technology Data Exchange (ETDEWEB)

    Kuroki, H.; Wakamatsu, T. [Miyazaki Prefectural Government Office, Miyazaki (Japan); Akizuki, T. [P.S. Corp., Tokyo (Japan); Uchida, H. [Oriental Construction Co. Ltd., Tokyo (Japan)

    1997-05-30

    This paper describes the design and construction of a ferro-concrete fixed arch bridge (Aoba Bridge) in Takachiho Town, Miyazaki Prefecture. The bridge face height is 100 m above the river bed, wherein, since constructing roads for the construction is impossible near the site, and considerations were given on the scenic viewpoint, the bridge took a structure to stride the valley with a single span. The construction is characterized by adopting a construction method using truss and assembled arch simultaneously, and a cantilever overhanging erection using special large mobile erection vehicles. An optimum arrangement length in the simultaneous construction method was discussed on the length of the assembled arch. Since the site is in the quasi-national park where there is a promenade to enjoy nature under the bridge, excavation was carried out by using blasting and drilling machines simultaneously paying attention not to drop excavated rock lumps into the valley. Because the structure system makes extremely complicated changes from one time to another during the erection, the safety of construction was ensured by measuring stress and deformation in each construction phase and comparing the measurements with the planned values. Dynamic analyses and vibration tests were also carried out in each phase. The bridge was completed in December 1996 requiring four years without causing a single problem. The simultaneous truss and assembled arch using construction method was demonstrated for the first time in the world. 8 refs., 29 figs., 7 tabs.

  7. 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,...

  8. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    CAI JianGuo; FENG Jian; CHEN Yao; HUANG LiFeng

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves-tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym-metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposedto simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch's modified slenderness.

  9. 乌溪江大桥方案设计%Scheme Design of Wuxijiang Bridge

    Institute of Scientific and Technical Information of China (English)

    张红星; 刘德宝; 余茂峰

    2011-01-01

    乌溪江大桥为浙江省遂昌县西南部跨越乌溪江水库的一座特大型桥梁.根据桥梁建设条件、景观、造价等因素,拟定了钢管混凝土拱桥、劲性骨架混凝土拱桥、连续刚构三种桥型方案.通过综合比较,确定钢管混凝土拱桥作为推荐桥型方案.%Wuxijiang Bridge is a long span bridge across Wuxijiang Reservoir in the southwest of Suichang County, Zhejiang Province. On the basis of the conditions of bridge construction, landscape, cost and other factors, three shemes of concrete-filled steel pipe arch bridge, concrete arch bridge with stiff skeleton, continuous rigid frame bridge are put forward. Through comprehensive comparison, concrete-filled steel pipe arch bridge is determined as recommended bridge type.

  10. Evolution Characteristic Analysis of Pressure-arch of a Double-arch Tunnel in Water-rich Strata

    Directory of Open Access Journals (Sweden)

    C. L. Li

    2016-03-01

    Full Text Available It is of importance to analyze the morphological characterization, the evolution process and the skewed effect of pressure-arch of a double-arch tunnel in the water-rich strata. Taking a buried depth 80 m double-arch tunnel as an example, a computational model of the double-arch tunnel was built by using FLAC3D technique. Then considering some aspects including groundwater conditions, tunnel depth, construction sequences and permeability coefficients, the coupling effect of stress field and seepage field in the pressure-arch of the double-arch tunnel was analyzed. The results show that the thickness of the pressure-arch induced by step-by-step excavation and display a step-descent skewed distribution from the left to the right of the double-arch tunnel. The permeability coefficient has a significant influence on the shape and the skewed effect of the pressure arch. The excavation of the bench method has a better arching condition than that of the expanding method. The abtained results provide a basic reference for the rock reinforcement design and safety construction of double-arch tunnels in the water-rich strata.

  11. Biotechnologie des archées

    OpenAIRE

    Querellou, Joel

    2010-01-01

    La majorité des enzymes utilisées dans l’industrie provient des bactéries et des levures. Mais les conditions extrêmes dans lesquelles se développent de nombreuses espèces d’archées font que leurs constituants cellulaires possèdent des propriétés et une stabilité propices à leur utilisation en biotechnologie.

  12. 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...

  13. Recurrent Pneumonia due to Double Aortic Arch

    Directory of Open Access Journals (Sweden)

    I. Sedighi

    2012-04-01

    Full Text Available Introduction: Pneumonia is one of the most common infections during childhood. In children with recurrent bacterial pneumonia complete evaluation for underlying factors is necessary. The most common underlying diseases include: antibody deficiencies , cystic fibrosis , tracheoesophageal fistula and increased pulmonary blood flow. Vascular ring and its pressure effect is a less common cause of stridor and recurrent pneumonia. Congenital abnormalities in aortic arch and main branches which form vascular ring around esophagus and trachea with variable pressure effect cause respiratory symptoms such as stridor , wheezing and recurrent pneumoniaCase Report: A 2 year old boy was admitted in our hospital with respiratory distress and cough . Chest x-Ray demonstrated right lobar pneumonia. He had history of stridor and wheezing from neonatal period and hospitalization due to pneumonia for four times. The patient received appropriate antibiotics. Despite fever and respiratory distress improvement, wheezing continued. Review of his medical documents showed fixed pressure effect on posterior aspect of esophagus in barium swallow. In CT angiography we confirmed double aortic arch.Conclusion: Double aortic arch is one of the causes of persistant respiratory symptom and recurrent pneumonia in children for which fluoroscopic barium swallow is the first non-invasive diagnostic method.(Sci J Hamadan Univ Med Sci 2012;19(1:70-74

  14. Variations among the primary maxillary dental arch forms using a polynominal equation model.

    Science.gov (United States)

    Tsai, Hung-Huey

    2003-01-01

    This study identifies arch symmetry and describes arch form variations in normal primary maxillary dental casts. Sixty-two percent of casts had asymmetrical arches, and 38% had symmetrical arches. Six types of arch form were identified according to the ratio of arch width to length. There were more long types than short types. The rounded and short types tended to have a more-symmetrical arch than did the long type. PMID:12739689

  15. Neural Network in Developing Software for Indentifying Arch Form

    Directory of Open Access Journals (Sweden)

    Johan Arief Budiman

    2013-06-01

    Full Text Available The treatment of Class I malocclusion treatment is to arrange the teeth position in a good arch form. Archform consists of tooth size and arch dimension (intercanine width, canine depth, intermolar width, molardepth. Several ways are developed to describe arch form. A lot of methods usedto describe arch formqualitatively.The objectiveofthis studyistodevelop qualitative arch form diagnostic references usingartificial neural network from pre-post treatment dental cast scanning result. Pre-post orthodontictreatment dental casts (1990-2006 from Post Graduate Clinic Faculty of Dentistry University of Indonesiaand 3 other orthodontistswere gathered andscanned.Dataweremeasured usingImage Toolandanalyzedusing Stata 9.ANOVA was used to compare arch forms (square, oval, tapered and gender (male andfemale, with each component of arch dimension upper and lowerjaw, before and after treatment; and alsoarch perimeter to kinds of treatmentThe results were compiled todeterminevariables inbuildingthesoftware for analyzing arch form qualitatively.The data from190 pre-post orthodontic treatment dentalcasts consisted of42 male (22.1% and 148 female (77.9% treated without extraction (32.63%,4Premolars extraction (48.42%, Upper Premolars extraction (11.05%, atypical extraction (7.90%.Gender and allvariables from pre treatment did not influence arch form, except kinds of treatment.Therefore, only post treatment data are included for arch form analysis. The shape of arch form (square,oval and tapered can be described qualitatively by software using artificial neural network.This softwarecoulddescribe arch form with the accuracy of 76.3158%.This studyconcludedthatIntercanine width,Canine depth, Intermolar width, and molar depth were variables that influencedarch form. A softwareusing artificial neural network to describe arch formqualitatively couldbe used for diagnostic reference toClass I malocclusion orthodontic post treatment.

  16. 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...

  17. 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.

  18. Evaluation of the fit of preformed nickel titanium arch wires on normal occlusion dental arches

    OpenAIRE

    Al-Barakati, Rakhn G.; Nasser D. Alqahtani; Abdulaziz AlMadi; Sahar F. Albarakati; ALKofide, Eman A.

    2016-01-01

    Aim: To determine the fits of preformed nickel titanium (NiTi) archwires on dental arches with normal occlusion. Methods: Forty sets of upper and lower plaster models were obtained from men and women with Class I occlusions. Preformed 0.016″ × 0.022″ NiTi archwires from Rocky Mountain Orthodontics (RMO), 3 M Unitek, Ormco, and Dentaurum were evaluated in terms of their fits on dental arches from male, female, and combined cases. Data were analyzed by using fourth- and sixth-order polynomia...

  19. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves- tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym- metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposed to simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch’s modified slenderness.

  20. An Electrostatically Actuated MEMS Arch Band-Pass Filter

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2013-01-01

    Full Text Available This work presents an investigation of the dynamics of micromachined arches resonators and their potential to be utilized as band-pass filters. The arches are actuated by a DC electrostatic load superimposed to an AC harmonic load. The dynamic response of the arch is studied analytically using a Galerkin-based reduced-order model when excited near its fundamental and third natural frequencies. Several simulation results are presented demonstrating interesting jumps and snap-through behavior of the arches and their attractive features for uses as band-pass filters, such as their sharp roll-off from pass bands to stop bands and their flat response.

  1. Normal azygos arch: retrotracheal visualization on frontal chest tomograms.

    Science.gov (United States)

    Austin, J H; Thorsen, M K

    1981-12-01

    Anteroposterior, linear tomograms of 78 adult subjects in the supine position revealed visualization of pleural reflections off the retrotracheal part of the normal azygos arch in 38 (49%). The course of the arch varied by about 3 cm. Five distinct patterns were found, mainly depending on the course of the inferior margin of the arch. The inferior margin varied from relatively superior retrotracheal positions to intermediate positions appearing to intersect the carina, to relatively inferior and right-sided positions posterior to the proximal right main bronchus. Recognition of these normal variations of the azygos arch should serve to differentiate them from abnormalities in this region. PMID:6976093

  2. Normal azygos arch: retrotracheal visualization on frontal chest tomograms

    International Nuclear Information System (INIS)

    Anteroposterior, linear tomograms of 78 adult subjects in the supine position revealed visualization of pleural reflections off the retrotracheal part of the normal azygos arch in 38 (49%). The course of the arch varied by about 3 cm. Five distinct patterns were found, mainly depending on the course of the inferior margin of the arch. The inferior margin varied from relatively superior retrotracheal positions to intermediate positions appearing to intersect the carina, to relatively inferior and right-sided positions posterior to the proximal right main bronchus. Recognition of these normal variations of the azygos arch should serve to differentiate them from abnormalities in this region

  3. Normal azygos arch: retrotracheal visualization on frontal chest tomograms

    Energy Technology Data Exchange (ETDEWEB)

    Austin, J.H.M. (Columbia-Presbyterian Medical Center, New York); Thorsen, M.K.

    1981-12-01

    Anteroposterior, linear tomograms of 78 adult subjects in the supine position revealed visualization of pleural reflections off the retrotracheal part of the normal azygos arch in 38 (49%). The course of the arch varied by about 3 cm. Five distinct patterns were found, mainly depending on the course of the inferior margin of the arch. The inferior margin varied from relatively superior retrotracheal positions to intermediate positions appearing to intersect the carina, to relatively inferior and right-sided positions posterior to the proximal right main bronchus. Recognition of these normal variations of the azygos arch should serve to differentiate them from abnormalities in this region.

  4. 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.

  5. A Functional Version of the ARCH Model

    CERN Document Server

    Hormann, Siegfried; Reeder, Ron

    2011-01-01

    Improvements in data acquisition and processing techniques have lead to an almost continuous flow of information for financial data. High resolution tick data are available and can be quite conveniently described by a continuous time process. It is therefore natural to ask for possible extensions of financial time series models to a functional setup. In this paper we propose a functional version of the popular ARCH model. We will establish conditions for the existence of a strictly stationary solution, derive weak dependence and moment conditions, show consistency of the estimators and perform a small empirical study demonstrating how our model matches with real data.

  6. Cathodic Protection of the Yaquina Bay Bridge

    Energy Technology Data Exchange (ETDEWEB)

    Bullard, Sophie J.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Russell, James H.; Laylor, H.M.; Cryer, C.B.

    2001-02-01

    The Yaquina Bay Bridge in Newport, Oregon, was designed by Conde B. McCullough and built in 1936. The 3,223-foot (982 m) structure is a combination of concrete arch approach spans and a steel through arch over the shipping channel. Cathodic protection is used to prevent corrosion damage to the concrete arches. The Oregon Department of Transportation (Oregon DOT) installed a carbon anode coating (DAC-85) on two of the north approach spans in 1985. This anode was operated at a current density of 6.6 mA/m2(0.6 mA/ft2). No failure of the conductive anode was observed in 1990, five years after application, or in 2000, 15 years after application. Thermal-sprayed zinc anodes 20 mils (0.5 mm) thick were applied to half the south approach spans beginning in 1990. Thermal-sprayed zinc anodes 15 mils (0.4 mm) thick were applied to the remaining spans in 1996. These anodes were operated at a current density of 2.2 mA/m2(0.2 mA/ft2). In 1999, four zones on the approach spans were included in a two-year field trial of humectants to improve zinc anode performance. The humectants LiNO3 and LiBr were applied to two zones; the two adjacent zones were left untreated as controls. The humectants substantially reduced circuit resistance compared to the controls.

  7. Three-dimensional measurement of foot arch in preschool children

    Directory of Open Access Journals (Sweden)

    Chang Hsun-Wen

    2012-09-01

    Full Text Available Abstract Background The prevalence of flexible flatfoot is high among preschool-aged children, but the effects of treatment are inconclusive due to the unclear definitions of normal flatfoot. To date, a universally accepted evaluation method of the foot arch in children has not been completely established. Our aims of this study were to establish a new method to evaluate the foot arch from a three dimensional perspective and to investigate the flexibility of the foot arch among children aged from two to six. Methods A total of 44 children aged from two to six years of age were put into five age groups in this study. The navicular height was measured with one leg standing, and both feet were scanned separately in both sitting and one leg standing positions to compute the foot arch volume. The arch volume index, which represents the ratio of the difference in volume between sitting and one leg standing positions to the volume when sitting was calculated to demonstrate the flexibility of the foot arch. The differences of measured parameters between each aged group were analyzed by one-way ANOVA. Results The arch volumes when sitting and standing were highly correlated with the navicular height. The navicular height ranged from 15.75 to 27 mm, the arch volume when sitting ranged from 6,223 to 11,630 mm3, and the arch volume when standing from 3,111 to 7,848 mm3 from two to six years of age. The arch volume index showed a declining trend as age increased. Conclusion This study is the first to describe the foot arch with volume perspective in preschool-aged children. The foot arch volume was highly correlated with the navicular height. Research results show both navicular height index and arch volume index gradually increase with age from two to six. At the same time the arch also becomes rigid with age from two to six. These results could be applied for clinical evaluation of the foot arch and post-treatment evaluation.

  8. Wildlife use of existing culverts and bridges in North Central Pennsylvania

    OpenAIRE

    Brudin, Carl O. III

    2003-01-01

    The Pennsylvania Department of Transportation (PENNDOT) District 3-0 initiated a study in North Central Pennsylvania evaluating existing bridges and culverts for use as underpasses by wildlife. This project was a two-phase study to investigate animal passage through existing drainage box culverts, arch culverts and bridges on existing highway systems. The objective of this study was to (1) determine whether wildlife are using existing structures as passageways based on wildlife sign and remot...

  9. Frost Resistance and Permeability of Cement Stabilized Gravel used as Filling Material for Pearl-Chain Bridges

    DEFF Research Database (Denmark)

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

    2014-01-01

    The Pearl-Chain Bridge Technology introduces a new innovative arch bridge solution which com-bines the statical advantages of an arch bridge with a minimum of traffic disturbance. The arch-shaped substructure is stabilized by a filling material, e.g. cement stabilized gravel, which should meet...... several requirements on its moisture properties. In this paper the frost resistance, the liquid water permeability and the water vapour permeability of cement stabilized gravel are examined for two different cement contents. It is found that a small increase in cement content from 4% to 5% increases...... the 28-days compressive strength from 6.2 MPa to 12.3 MPa. The frost resistance of cement stabilized gravel with 5% cement content is better than for cement stabilized gravel with 4% cement content. The liquid water permeability coefficient and the water vapour permeability coefficient are significantly...

  10. Blood flow characteristics in the aortic arch

    Science.gov (United States)

    Prahl Wittberg, Lisa; van Wyk, Stevin; Mihaiescu, Mihai; Fuchs, Laszlo; Gutmark, Ephraim; Backeljauw, Philippe; Gutmark-Little, Iris

    2012-11-01

    The purpose with this study is to investigate the flow characteristics of blood in the aortic arch. Cardiovascular diseases are associated with specific locations in the arterial tree. Considering atherogenesis, it is claimed that the Wall Shear Stress (WSS) along with its temporal and spatial gradients play an important role in the development of the disease. The WSS is determined by the local flow characteristics, that in turn depends on the geometry as well as the rheological properties of blood. In this numerical work, the time dependent fluid flow during the entire cardiac cycle is fully resolved. The Quemada model is applied to account for the non-Newtonian properties of blood, an empirical model valid for different Red Blood Cell loading. Data obtained through Cardiac Magnetic Resonance Imaging have been used in order to reconstruct geometries of the the aortic arch. Here, three different geometries are studied out of which two display malformations that can be found in patients having the genetic disorder Turner's syndrome. The simulations show a highly complex flow with regions of secondary flow that is enhanced for the diseased aortas. The financial support from the Swedish Research Council (VR) and the Sweden-America Foundation is gratefully acknowledged.

  11. HADRIAN’S ARCHES FROM ROMAN PERIOD, JORDAN: A COMPARATIVE STUDY

    OpenAIRE

    Nassar, Mohammad

    2014-01-01

    This article provides a study of Hadrian arches from three main locations: Jordan, Turkey, and Greece. Collectively within these countries, four arches have been found the Hadrian arch at Jerash (Gerasa) in Jordan, the Hadrian arch in Antalya and Ephesus, both in Turkey, and the Hadrian arch in Athens, Greece. The units of our analysis include all the different designs and plans used in constructing these arches. The analyzed design and planning units constitute a database that enables the...

  12. Level-ARCH Short Rate Models with Regime Switching

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    This paper introduces regime switching volatility into level- ARCH models for the short rates of the US, the UK, and Germany. Once regime switching and level effects are included there are no gains from including ARCH effects. It is of secondary importance exactly how the regime switching...

  13. Adult presentation with vascular ring due to double aortic arch.

    Science.gov (United States)

    Kafka, Henryk; Uebing, Anselm; Mohiaddin, Raad

    2006-11-01

    This is a case report on the use of cardiovascular magnetic resonance imaging to diagnose vascular ring due to double aortic arch in an adult presenting with an abnormal chest X-ray. The experience in this case and the literature review identify the benefits of using cardiovascular magnetic resonance imaging to clarify complex aortic arch anatomy.

  14. Double aortic arch and nasogastric tubes: A fatal combination

    Institute of Scientific and Technical Information of China (English)

    Julia Massaad; Kelly Crawford

    2008-01-01

    Double aortic arch is a common form of complete vascular ring that encircles both the trachea and the esophagus, and presents with various respiratory and esophageal symptoms, usually in the pediatric population.We present a case of double aortic arch in an adult patient that manifested as massive upper gastrointestinal bleeding after prolonged nasogastric intubation.

  15. Swallowing threshold parameters of subjects with shortened dental arches.

    NARCIS (Netherlands)

    Kreulen, C.M.; Witter, D.J.; Tekamp, F.A.; Slagter, A.P.; Creugers, N.H.J.

    2012-01-01

    OBJECTIVES: To quantify swallowing threshold parameters of subjects with a moderate shortened dental arch dentition (SDA: missing molar teeth, but premolar teeth in occluding position and uninterrupted anterior regions) compared to subjects with a complete dental arch dentition (CDA). METHODS: Fourt

  16. Modelling subset multivariate ARCH model via the AIC principle

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper we consider the problem of identifying a parsimonious subset multivariate ARCH model based on the AIC principle. The proposed approach can reduce the number of parameters in the final ARCH specification and allows for non-constant correlations between the components. Some simulation results illustrate the viability of the proposed procedure.

  17. Aortic arch vessel anomalies associated with persistent trigeminal artery.

    Science.gov (United States)

    Lotfi, Mehrzad; Nabavizadeh, Seyed Ali; Foroughi, Amin Abolhasani

    2012-01-01

    Developmental anomalies of the aortic arch vessels and persistent trigeminal artery that is the most common of the four anomalous carotid-basilar anastomoses are repeatedly reported in the literature as separate entities. Herein we report a previously undescribed variant including the coexistence of persistent trigeminal artery, truncus bicaroticus and direct origin of left vertebral artery from aortic arch. PMID:22542381

  18. Seismic multi-arch structures in East China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In previous papers (Wencai, 2002, 2003), the author has analyzed the deep seismic reflection profiles along some of the Mesozoic plutons in East China, and has pointed out that the crustal structures around these intrusions usually correlate with a special seismic fabric called the seismic multi-arch structure. This paper will continue to show main characteristics of the seismic multi-arch structures and discuss their relationship with mantle-origin magmatism and the lithospheric thinning process. Calibration of seismic reflectors in Chinese continental drilling sites shows that small-scale arch-like reflectors can be generated by fractured eclogites or other plutons, they do not belong to the multi-arch structure specially discussed in the paper. The multi-arch structure is characterized by several arch-like reflectors distributed in both the upper and lower crust with granitoid plutons or stocks exposed on the surface, which do not have obvious negative Europium anomalies. Based on the distribution pattern of arch reflectors, the multi-arch magmatic structures can be divided into three main types, namely the simple vertical combination type, the spread arch magmatic structure and the arch-bouquet structure. All of them correlate to mantle-origin magmatism, but occur in different places. The spread arch magmatic structures occur within a Mesozoic/Cenozoic rift zone with very thin and hot lithosphere. The vertical combination type of the multi-arch structures occurred near the rift zones where lithosphere was thin and hot. The arch-bouquet magmatic structures occur far from the rift zones where the lithosphere is not hot. The continental rifting acted as the late episode of the lithospheric thinning process seeing that the rift zones usually coincide with the thinnest parts of the lithosphere in East China. In different locations within the lithospheric thinning areas, mantle-origin magmatic activities have different characteristics, which might generate different

  19. 紧水滩大桥桥型方案设计%The Bridge Type Design Scheme of Jinshuitan Bridge

    Institute of Scientific and Technical Information of China (English)

    杨成峰; 邱白

    2014-01-01

    This paper introduces the design scheme of bridge type of Jinshuitan Bridge, compares the three kinds of schemes of the deck concrete arch bridge, prestressed concrete T beams and prestressed concrete continuous rigid frame bridge, and gi-ves the relevant conclusions and recommendations. Its design experience can be used for reference in the professional design personnel.%本文介绍了紧水滩大桥的桥型方案设计,比较了上承式混凝土拱桥、预应力砼 T 梁及预应力砼连续刚构等三种桥型方案,并给出相关结论和建议。其设计经验可供专业设计人员参考。

  20. Left testicular artery arching over the ipsilateral renal vein

    Institute of Scientific and Technical Information of China (English)

    Munekazu Naito; Hayato Terayama; Yoichi Nakamura; Shogo Hayashi; Takayoshi Miyaki; Masahiro Itoh

    2006-01-01

    Aim: To report two cases of the left testicular artery arching over the left renal vein (LRV) before running downward to the testis. Methods: The subjects were obtained from two Japanese cadavers. During the student course of gross-anatomical dissection, the anatomical relationship between the testicular vessels and the renal vein was specifically observed. Results: The arching left testicular artery arose from the aorta below the LRV and made a loop around the LRV, which appeared to be mildly compressed between the arching artery and the psoas major muscle.Conclusion: Clinically, compression of the LRV between the abdominal aorta and the superior mesenteric artery occasionally induces LRV hypertension, resulting in varicocele, orthostatic protenuria and hematuria. Considering that the incidence of a left arching testicular artery is higher than that of a right one, an arching left artery could be an additional cause of LRV hypertension.

  1. Effect of Obesity on Arch Index in Young Adults

    Directory of Open Access Journals (Sweden)

    Sneha Sameer Ganu

    2013-01-01

    Full Text Available Background: Excessive increases in weight bearing forces caused by obesity may negatively affect the lower limbs and feet but minimal research has examined the long-term loading effects of obesity on the musculoskeletal system, particularly in reference to the feet. Objectives: The purpose of the study was to investigate the effect of obesity on medial longitudinal arch of foot in young adults. Method: 60 subjects, 30 obese & 30 non obese were assessed for height & weight using standard technique. Radiographic images under static condition were used for calculating the arch index. Result: The arch index of obese subjects was significantly lower than the non obese subjects & there is a negative correlation between the BMI & the arch index. Conclusion: These results suggests that obesity lowers the medial longitudinal arch of foot.

  2. Seismic behavior of concrete filled steel tubular arch structures

    Institute of Scientific and Technical Information of China (English)

    Xiong Feng; Sashi K Kunnath; Liu Haowu

    2005-01-01

    Shaking table tests of a 1:10 scale arch model performed to investigate the seismic behavior and resistance of concrete filled steel tubular (CFT) arch structures are described in this paper. The El-Centro record and Shanghai artificial wave were adopted as the input excitation. The entire test process can be divided into three stages depending on the lateral brace configurations, i.e., fully (five) braced, two braces removed, and all braces removed. A total of 46 tests, starting from the elastic state to failure condition, have been conducted. The natural vibration frequencies, responses of acceleration,displacement and strain were measured. From the test results, it is demonstrated that the CFT arch structures are capable of resisting severe ground motions and that CFT arches offer a credible alternative to reinforced concrete arches, especially in regions of high seismic intensity.

  3. Implant restoration of edentulous jaws with 3D software planning, guided surgery, immediate loading, and CAD-CAM full arch frameworks

    OpenAIRE

    Silvio Mario Meloni; Giacomo De Riu; Milena Pisano; Francesco Maria Lolli; Alessandro Deledda; Guglielmo Campus; Antonio Tullio

    2013-01-01

    Purpose. The aim of this study was to analyze the clinical and radiographic outcomes of 23 edentulous jaws treated with 3D software planning, guided surgery, and immediate loading and restored with CAD-CAM full arch frameworks. Materials and Methods. This work was designed as a prospective case series clinical study. Twenty patients have been consecutively rehabilitated with an immediately loaded implant supported fixed full prosthesis. A total of 120 fixtures supporting 23 bridges were place...

  4. Mission archéologique islamique

    Directory of Open Access Journals (Sweden)

    Claire Hardy-Guilbert

    1997-11-01

    Full Text Available La troisième mission exploratoire du programme de recherches archéologiques sur la période islamique au Yémen s'est déroulée du 1 au 22 décembre 1995, en collaboration avec le Dr Ahmad Bataya, et a porté sur la côte méridionale, entre Abyan et Sayhut. Outre une étude approfondie de la ville d'al-Shihr, les prospections ont porté sur les régions d'Abyan, Ahwar et Sayhut. Prospection de la côte : Si Aden-même, le plus grand port yéménite depuis le 10ème siècle, est aujourd'hui trop urba...

  5. The assessment of crowding without the need to record arch perimeter. Part I: Arches with acceptable alignment.

    Science.gov (United States)

    Battagel, J M

    1996-05-01

    A simplified, mathematically determined technique for calculating arch perimeter (the overlap method) is described and its validity in determining an accurate assessment of crowding is tested. Indices, expressed in millimetres of crowding or spacing, were computed for both the whole arch and the labial segment alone. Study casts of 36 individuals with clinically acceptable lower arches were used to validate the method. The degree of crowding or spacing calculated was compared with a "clinical' assessment of each arch, in which the irregularity was measured directly using a steel ruler. Various calculation schemes were tested. Depending on exactly how the overlap was determined, the results varied slightly. Although the arches showed acceptable alignment, it was preferable to include a strategy for normalizing the positions of any rotated teeth before the overlaps were calculated. Repositioning any bucco-lingually displaced teeth into the line of the arch, however, was not useful. For the complete arch good agreement with the clinical assessment was reached on 31 occasions and for the labial segment, all but one appraisals were within 0.5 mm of each other. In the remaining instances (five complete arches and one labial segment), the degree of crowding or spacing was between 0.5 and 1 mm of the clinical assessment. Considering that clinical measurement of minor degrees of crowding and spacing cannot be precise, these results were considered acceptable. The method was easy to use, relying only on the recording of mesio-distal tooth widths and was acceptably reproducible. The technique would therefore appear to provide a valid yet simple research tool with which to record the degree of crowding. Its ability to cope with irregular and crowded arches will be the subject of a subsequent review.

  6. Arch development with trans-force lingual appliances.

    Science.gov (United States)

    Clark, William J

    2005-01-01

    Trans-Force lingual appliances are designed to correct arch form in patients with contracted dental arches. Interceptive treatment with this new series of pre-activated lingual appliances offers new possibilities for arch development, in combination with fixed appliances. Palatal and lingual appliances insert in horizontal lingual sheaths in molar bands. No activation is required after the appliance is fitted, and this principle is extended to a series of appliances for sagittal and transverse arch development. Both sagittal and transverse appliances have additional components to achieve 3-way expansion where this is indicated. The invisible lingual appliances may be used in correction of all classes of malocclusion at any stage of development, from mixed dentition through permanent dentition, and this approach has wide indications in adult treatment. PMID:15794037

  7. Nonstationary ARCH and GARCH with t-distributed Innovations

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Søndergaard; Rahbek, Anders

    Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t-distribut......Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t......-distribution. With T denoting sample size, classic square-root T-convergence is shown to hold with closed form expressions for the multivariate covariances....

  8. Clarifying the anatomy of the fifth arch artery

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Gupta

    2016-01-01

    Full Text Available The artery allegedly forming in the fifth pharyngeal arch has increasingly been implicated as responsible for various vascular malformations in patients with congenitally malformed hearts. Observations from studies on developing embryos, however, have failed to provide support to substantiate several of these inferences such that the very existence of the fifth arch artery remains debatable. To the best of our knowledge, in only a solitary human embryo has a vascular channel been found that truly resembled the artery of the fifth arch. Despite the meager evidence to support its existence, the fifth arch artery has been invoked to explain the morphogenesis of double-barreled aorta, some unusual forms of aortopulmonary communications, and abnormalities of the brachiocephalic arteries. In most of these instances, the interpretations have proved fallible when examined in the light of existing knowledge of cardiac development. In our opinion, there are more plausible alternative explanations for the majority of these descriptions. Double-barreled aorta is more likely to result from retention of the recently identified dorsal collateral channels while abnormalities of brachiocephalic arteries are better explained on the basis of extensive remodeling of aortic arches during fetal development. Some examples of aortopulmonary communications, nonetheless, may well represent persistence of the developing artery of the fifth pharyngeal arch. We here present one such case - a patient with tetralogy of Fallot and pulmonary atresia, in whom the fifth arch artery provided a necessary communication between the ascending aorta and the pulmonary arteries. In this light, we discuss the features we consider to be essential before attaching the tag of "fifth arch artery" to a candidate vascular channel.

  9. A comparison of four methods of predicting arch length.

    Science.gov (United States)

    Gardner, R B

    1979-04-01

    1. Four arch length prediction equations (Nance, Johnston-Tanaka, Moyers, and Hixon-Oldfather) were compared by examining pretreatment casts, pretreatment intraoral radiographs, and posttreatment casts of forty-one patients of mixed-dentition age. 2. A comparison of correlation coefficients and slopes of the predicted arch length versus the actual arch lengths revealed that the Hixon-Oldfather method conformed closest to the ideal. 3. No combination of the four methods produced a more accurate equation than the single most accurate method. 4. Neither the sex of the patient nor the type of occlusion affected the prediction accuracy of any of the four equations. 5. All methods tend to overpredict the arch length size by 1 to 3 mm., with the exception of the Hixon-Oldfather equation, which underpredicted by approximately 0.5 mm. 6. An analysis of the intrainvestigator error showed a very low standard error of estimate for individual tooth measurements and for the prediction values. 7. A variance analysis showed that most of the variation was due to arch length (85%), a slight amount was due to the prediction method (8%), and 6% of the variation was due to the rater. 8. A low correlation was found between space available versus actual discrepancy and space available versus actual arch length. 9. High correlation coefficients were found for the predicted arch lengths when compared with the actual arch lengths. As expected, the correlation coefficients for the predicted widths of only the canines and premolars compared with the actual widths were not quite as high. PMID:285614

  10. Comparison of arch forms between Turkish and North American

    OpenAIRE

    Ahmet A. Celebi; Hakan Keklik; Enes Tan; Ucar, Faruk I.

    2016-01-01

    ABSTRACT Objective: The aim of this study was to clarify the morphological differences in the mandibular arches of Turkish and North American white subjects. Methods: The sample included 132 Turkish (34 Class I, 58 Class II, and 40 Class III) and 160 North American (60 Class I, 50 Class II, and 50 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of patients' mandibular dental arches. Clinical bracket points were calculated for ...

  11. Comparison of arch forms between Turkish and North American

    Directory of Open Access Journals (Sweden)

    Ahmet A. Celebi

    2016-04-01

    Full Text Available ABSTRACT Objective: The aim of this study was to clarify the morphological differences in the mandibular arches of Turkish and North American white subjects. Methods: The sample included 132 Turkish (34 Class I, 58 Class II, and 40 Class III and 160 North American (60 Class I, 50 Class II, and 50 Class III subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of patients' mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The subjects were grouped according to arch form types (tapered, ovoid and square in order to have frequency distribution compared between ethnic groups in each Angle classification. Results: The Turkish group showed significantly lower molar depth and more significant molar width-depth (W/D ratio in all three Angle classifications. On the other hand, the Turkish group also showed a significantly larger intercanine width in Class III malocclusion and intermolar width in Class II malocclusion. The most frequent arch forms seen were the ovoid arch form in the Turkish group and the tapered form in the white group. Conclusions: Our results demonstrate that when treating Turkish patients, one should expect to use preformed ovoid arch form orthodontic wires in a significant percentage of patients.

  12. Developmental feature of the lumbosacral vertebral arch in childhood

    International Nuclear Information System (INIS)

    We investigated a developmental feature of the lumbosacral vertebral arch in childhood that has rarely been reported previously. Sixty-seven patients underwent functional posterior rhizotomy from September 2000 to June 2006 at National Center for Child Health and Development. Sixty of these patients, who had no deformity in their lumbosacral spine, were included in this study and their Computed Tomography (CT) images were analyzed retrospectively. There were 36 boys and 24 girls, aged from 2-12 years. The rate and mean number of non-union vertebral arches between L1 and S3 were 78.3% (95% CI, 65.8-87.9%) and 1.7 (standard deviation (SD), 1.3). The non-union arch was most frequently found at the S1 level, and was more significantly observed in the younger age group (2-5 years of age). The S4 and S5 arches, which often remained open as the sacral hiatus, were constantly open in childhood. This study demonstrates that the vertebral arches of the lumbosacral spine in normal development are often not fused during childhood. It is important to differentiate normal non-union arches from pathological spina bifida. (author)

  13. Assessing Static Performance of the Dashengguan Yangtze Bridge by Monitoring the Correlation between Temperature Field and Its Static Strains

    OpenAIRE

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

    2015-01-01

    Taking advantage of the structural health monitoring system installed on the steel truss arch girder of Dashengguan Yangtze Bridge, the temperature field data and static strain data are collected and analyzed for the static performance assessment of the bridge. Through analysis, it is found that the static strain changes are mainly caused by temperature field (temperature and temperature difference) and train. After the train-induced static strains are removed, the correlation between the rem...

  14. Design of Steel Arch Footbridge on Circular Curve%位于圆曲线上的人行钢拱桥设计

    Institute of Scientific and Technical Information of China (English)

    褚文涛; 夏刚; 杨帆

    2015-01-01

    为满足金象湖公园1号人行桥跨越公园水域、景观要求,以及保障行人和消防车辆通行,采用“空间曲线桥型、网状异形支撑”设计思路进行桥梁设计。该桥设计为全长79.48 m的上承式钢结构刚架拱桥,拱肋及主梁均采用异形钢箱梁,拱梁结合段处拱肋与主梁结合为一整体,基础采用斜 PHC管桩基础。通过将拱桥平面投影设置于圆曲线上,达到“空间曲线桥型”的桥梁造型要求;在拱座顶部设置树杈形装饰构件既实现了“网状异形支撑”的生态景观效果,也使得主体结构受力模式更明确、合理;通过优化拱桥平曲线半径,使结构静、动力性能与景观需求达到平衡;采用斜向 PHC管桩群桩基础,增强了基础抗推刚度、节省了工程投资。结构分析结果表明,桥梁结构应力、变形及自振竖向频率结果均满足规范要求。%To address the requirements of water conservancy and landscape effect and ensure the safety of the passing pedestrians and fire engines ,the No .1 Footbridge in the Golden Elephant Lake Park is designed following the concept of “a spatial curved bridge with irregular network sup‐ports” .The bridge is a deck‐type rigid‐frame steel arch bridge with a total length of 79 .48 m .The arch ribs and main girder adopt the irregular steel box cross section ,at the arch‐rib joint section , the arch ribs and the girder are connected to be an integrated structure .The foundation of the foot‐bridge adopts the oblique PHC pipe piles .By projecting the plan of the arch bridge on a circular curve ,the shaping requirements of spatial curved bridge w as realized .Branch‐shaped decorative components were placed on the top of the arch seats to realize the ecological landscape effect of “ir‐regular network supports” ,which also enables the load bearing mode of main structure be more clear and rational .The static and dynamic performance

  15. Branched and fenestrated options to treat aortic arch aneurysms.

    Science.gov (United States)

    Maurel, Blandine; Mastracci, Tara M; Spear, Rafaelle; Hertault, Adrien; Azzaoui, Richard; Sobocinski, Jonathan; Haulon, Stephan

    2016-10-01

    Conventional surgical repair of aortic arch aneurysms using cardiopulmonary bypass and hypothermic circulatory arrest remains the gold standard, however it is associated with a substantial mortality and morbidity rate, especially in the elderly. Hybrid techniques avoid aortic cross-clamping and circulatory arrest, but are of limited use and are only applicable to selected patients. The development of new devices to treat aortic arch aneurysms endovascularly has the potential to offer a treatment modality to patients unfit for an open repair. We present the challenges specific to endovascular arch repair based on our experience and the literature available from the first experience in 1999 to the third generation graft currently commonly used. Following an initial learning curve associated with the use of the third generation arch branch device, along with careful patient selection and operator experience, early results are promising. Technical success was achieved in all cases, there was no early mortality and strokes were noted in 11%. As with branched and fenestrated technology for thoracoabdominal aneurysm repair, the use of total endovascular repair for arch pathology will require an evolution in endovascular practice and device design. However, at present, the early use of the latest generation device offers a novel approach to patients who previously had no surgical options. PMID:27332680

  16. Three-dimensional stiffness of the carpal arch.

    Science.gov (United States)

    Gabra, Joseph N; Li, Zong-Ming

    2016-01-01

    The carpal arch of the wrist is formed by irregularly shaped carpal bones interconnected by numerous ligaments, resulting in complex structural mechanics. The purpose of this study was to determine the three-dimensional stiffness characteristics of the carpal arch using displacement perturbations. It was hypothesized that the carpal arch would exhibit an anisotropic stiffness behavior with principal directions that are oblique to the conventional anatomical axes. Eight (n=8) cadavers were used in this study. For each specimen, the hamate was fixed to a custom stationary apparatus. An instrumented robot arm applied three-dimensional displacement perturbations to the ridge of trapezium and corresponding reaction forces were collected. The displacement-force data were used to determine a three-dimensional stiffness matrix using least squares fitting. Eigendecomposition of the stiffness matrix was used to identify the magnitudes and directions of the principal stiffness components. The carpal arch structure exhibited anisotropic stiffness behaviors with a maximum principal stiffness of 16.4±4.6N/mm that was significantly larger than the other principal components of 3.1±0.9 and 2.6±0.5N/mm (pcarpal tunnel which is accounted for by the stiff transverse ligaments that tightly bind distal carpal arch. The minimal principal stiffness is attributed to the less constraining articulation between the trapezium and scaphoid. This study provides advanced characterization of the wrist׳s three-dimensional structural stiffness for improved insight into wrist biomechanics, stability, and function.

  17. Studies on Technical Development of Railway Steel-Concrete Composite Cirider Bridges in China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Steel-concrete composite girder bridge boasts the advantages of strong rigidity,low noise and low construction height.Along with the large-scale construction of passengerdedicated lines (PDL) and high-speed lines (HSL),tests and researches on steel-concrete composite girder bridges have been conducted with the main types of which including steel plate girder-concrete composite girder bridge,deck steel truss girder-concrete composite girder bridge,through steel truss girder-concrete composite girder bridge and through type tied arch composite girder bridge.Based on the application and researches on steel-concrete composite technology and in combination with the engineering construction of railway bridges,the construction of HSL and PDL and upgrading of existing lines for speed-up in China,this paper analyzes the main structural forms of through steel truss girder-concrete composite girder bridges with different spans and structure systems,carries out studies on the force acted upon these bridges and the related theory and methods for design and computation,and puts forward the solutions required in relation to the key technologies for further development of railway steel-concrete composite girder bridges.

  18. Experiment on interface separation detection of concrete-filled steel tubular arch bridge using accelerometer array

    Science.gov (United States)

    Pan, Shengshan; Zhao, Xuefeng; Zhao, Hailiang; Mao, Jian

    2015-04-01

    Based on the vibration testing principle, and taking the local vibration of steel tube at the interface separation area as the study object, a real-time monitoring and the damage detection method of the interface separation of concrete-filled steel tube by accelerometer array through quantitative transient self-excitation is proposed. The accelerometers are arranged on the steel tube area with or without void respectively, and the signals of accelerometers are collected at the same time and compared under different transient excitation points. The results show that compared with the signal of compact area, the peak value of accelerometer signal at void area increases and attenuation speed slows down obviously, and the spectrum peaks of the void area are much more and disordered and the amplitude increases obviously. whether the input point of transient excitation is on void area or not is irrelevant with qualitative identification results. So the qualitative identification of the interface separation of concrete-filled steel tube based on the signal of acceleration transducer is feasible and valid.

  19. 历史上的拱桥%THE ARCH BRIDGES IN HISTORY

    Institute of Scientific and Technical Information of China (English)

    罗福午

    2002-01-01

    @@ 拱,作为一种结构,在荷载作用下主要承受轴向压力,用拱券或拱肋作为主要承重结构的桥梁称为拱桥.显然,受压性能极好的石拱桥是历史上最先发展的桥梁之一.在古代,拱桥起源于模仿石灰岩溶洞中天然形成的"天生桥".据说美索不达米亚(Mesopotamia,中亚底格里斯河和幼发拉底河流域间的古王国,现今伊拉克所在地)人,曾在古罗马人建造石拱桥以前的2000多年,就造过这种桥梁.

  20. 淦河桥梁方案设计研究%Design and Research on Bridge Scheme of Gan River

    Institute of Scientific and Technical Information of China (English)

    蔡忠华

    2016-01-01

    Following the principal of applicable,economical,safe and beautiful and taking the bridge crossing Gan River in Jingui west road in Xianning City as the engineering background,four types of bridge design schemes are introduced,namely simple supported girder bridge,continuous girder bridge,through tied-arch bridge,and cable-stayed bridge without backstays.The tied arch bridge is chosen as the recommended proposal by taking bridge design,landscape feature,construction feasibil-ity and economy into comprehensive consideration.%遵循“适用、经济、安全、美观”的桥梁设计基本原则,以咸宁市金桂西路跨淦河大桥为工程背景,提供了4种桥梁设计方案:无背索斜拉桥,预应力混凝土连续梁桥、预应力混凝土简支 T梁桥、下承式系杆拱桥。综合考虑论证桥梁构造设计、景观特色、施工可行性和经济性等因素,选取下承式系杆拱桥作为推荐方案。

  1. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

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

  2. Evaluation of dental arch width and form changes after orthodontic treatment and retention with a new computerized method.

    Science.gov (United States)

    Taner, Tülin Ugur; Ciger, Semra; El, Hakan; Germeç, Derya; Es, Alphan

    2004-10-01

    The purpose of this study was to evaluate longitudinal arch width and form changes and to define arch form types with a new computerized method. Maxillary and mandibular models of 21 Class II Division 1 patients were examined before treatment (T(0)), after treatment (T(1)), and an average of 3 years after retention (T(2)). Arch width measurements were made directly on scanned images of maxillary and mandibular models. Arch form changes at T(0)-T(1) and T(1)-T(2) were evaluated by superimposing the computer-generated Bezier arch curves with a computer program. Types of dental arch forms were defined by superimposing them with the pentamorphic arch system, which included 5 different types of arch forms: normal, ovoid, tapered, narrow ovoid, and narrow tapered. Maxillary arch widths were increased during orthodontic treatment. Mandibular posterior arch widths were also increased. The expansion of the mandibular arch forms was less than in the maxillary arch forms. Arch width changes were generally stable, except for reduction in maxillary and mandibular interlateral, inter-first premolar, and mandibular intercanine widths. Pretreatment maxillary arch forms were mostly tapered; mandibular arch forms were tapered and narrow tapered. In maxillary arch forms, 76% of the treatment changes were maintained. Mandibular arch form was maintained in 67% of the sample, both during treatment and after retention. In mandibular arches, 71% of orthodontically induced arch form changes were maintained. PMID:15470349

  3. [A treatment chart adapted to the arch form].

    Science.gov (United States)

    Bocquet-Moreau, E; Danguy, Ch; Bertrand, J; Danguy, M

    2005-12-01

    Arch wires used in orthodontic treatment must conform to the shape of the dental arches so that in their final positions teeth will be set in a pathway of neuromuscular equilibrium. However, sometimes distortions of the alveoli deform the shape of the arch. In such cases the treatment charts constructed on the actual alveolo-dental relationship will not reflect desired objectives. We believe that the transverse muco-gingival dimension Andrews called the Wala line responds better to therapeutic requirements. Moreover, molar attachments, key elements of a full-banded appliance, are in harmony with it. So the type of chart that the authors propose for use with the Straight Wire technique, one based on the Wala line, will help orthodontists place teeth at the conclusion of orthodontic treatment in the best possible relationships to patients' specific anatomic configurations. PMID:16471375

  4. In-Plane MEMS Shallow Arch Beam for Mechanical Memory

    Directory of Open Access Journals (Sweden)

    Md Abdullah Al Hafiz

    2016-10-01

    Full Text Available We demonstrate a memory device based on the nonlinear dynamics of an in-plane microelectromechanical systems (MEMS clamped–clamped beam resonator, which is deliberately fabricated as a shallow arch. The arch beam is made of silicon, and is electrostatically actuated. The concept relies on the inherent quadratic nonlinearity originating from the arch curvature, which results in a softening behavior that creates hysteresis and co-existing states of motion. Since it is independent of the electrostatic force, this nonlinearity gives more flexibility in the operating conditions and allows for lower actuation voltages. Experimental results are generated through electrical characterization setup. Results are shown demonstrating the switching between the two vibrational states with the change of the direct current (DC bias voltage, thereby proving the memory concept.

  5. Game model of safety monitoring for arch dam deformation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Arch dam deformation is comprehensively affected by water pressure,temperature,dam’s structural behavior and material properties as well as other factors.Among them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam’s structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance factors.Therefore,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of dam.On the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

  6. LANGER’S AXILLARY ARCH AND ITS CLINICAL IMPLICATIONS

    Directory of Open Access Journals (Sweden)

    Jyothi K C

    2014-09-01

    Full Text Available Introduction: The axillary arch muscle of Langer is the most common anatomical variant of axillary musculature which is of clinical and surgical importance. It may lead to neurovascular compression syndrome in the cervicoaxillary region and can be misinterpreted while examining axilla and also impairs movements of shoulder joint. Observation: During routine dissection of axilla for undergraduate teaching, an unusual muscular slip in the left axilla was observed .The muscular slip was extending from lattisimus dorsi muscle to undersurface of pectoralis major muscle, arching over axillary vessels and cords of brachial plexus. Conclusion: The axillary arch may cause obstruction to axillary vessels and nerves and may be involved in thoracic outlet syndrome and shoulder instability. The knowledge of this muscular variant could help to minimize intraoperative complications related to surgeries in or nearby axilla such as mastectomy, breast reconstruction and axillary lymphadenectomy or lymph node biopsy.

  7. 福建廊桥的形态与文化研究%Research on the morphology and culture of Fujian covered bridges

    Institute of Scientific and Technical Information of China (English)

    戴志坚

    2012-01-01

    福建廊桥尤其木拱廊桥造型美观、结构科学,具有鲜明的地方特色和重要的文物价值。从福建廊桥的结构、功能入手,分析平梁木廊桥、八字撑木廊桥、木拱廊桥、石拱廊桥的类型特征,总结廊桥丰富的文化内涵,提出福建廊桥的研究内容和方向。%The Fujian covered bridges, especially the wooden arched covered bridges, are beautiful with scientific structures. They have distinctive local features and important cultural values. This paper analyzes the structural typology of the flat beam covered bridges, the Chinese- Eight-type tie covered bridges, the wooden arched covered bridges and the stone arched covered bridges through structures and functions. It summarizes the abundant cultural values of the covered bridges, and suggests the future research content and orientation.

  8. Optical silencing of C. elegans cells with arch proton pump.

    Directory of Open Access Journals (Sweden)

    Ayako Okazaki

    Full Text Available BACKGROUND: Optogenetic techniques using light-driven ion channels or ion pumps for controlling excitable cells have greatly facilitated the investigation of nervous systems in vivo. A model organism, C. elegans, with its small transparent body and well-characterized neural circuits, is especially suitable for optogenetic analyses. METHODOLOGY/PRINCIPAL FINDINGS: We describe the application of archaerhodopsin-3 (Arch, a recently reported optical neuronal silencer, to C. elegans. Arch::GFP expressed either in all neurons or body wall muscles of the entire body by means of transgenes were localized, at least partially, to the cell membrane without adverse effects, and caused locomotory paralysis of worms when illuminated by green light (550 nm. Pan-neuronal expression of Arch endowed worms with quick and sustained responsiveness to such light. Worms reliably responded to repeated periods of illumination and non-illumination, and remained paralyzed under continuous illumination for 30 seconds. Worms expressing Arch in different subsets of motor neurons exhibited distinct defects in the locomotory behavior under green light: selective silencing of A-type motor neurons affected backward movement while silencing of B-type motor neurons affected forward movement more severely. Our experiments using a heat-shock-mediated induction system also indicate that Arch becomes fully functional only 12 hours after induction and remains functional for more than 24 hour. CONCLUSIONS/SGNIFICANCE: Arch can be used for silencing neurons and muscles, and may be a useful alternative to currently widely used halorhodopsin (NpHR in optogenetic studies of C. elegans.

  9. Management of hypoplastic aortic arch associated with neonatal coarctation.

    Science.gov (United States)

    Caspi, J; Ilbawi, M N; Muster, A; Roberson, D; Arcilla, R

    1994-12-01

    Controversy still exists as to whether hypoplastic aortic arch frequently associated with neonatal coarctation, should be enlarged at the time of coarctation repair. To determine the indications for and the outcome of repair of hypoplastic aortic arch, pre- and postoperative angiograms/echocardigraphy of 77 cases with isolated (n = 25, Group 1) or complex (n = 52, Group 2) neonatal coarctation operated upon between 1/80 and 12/89 were reviewed. Age was 5-14 days (mean 8 +/- 1.6). Aortic arch/ascending aorta diameter ratio (AR/AA) as a measure of the degree of aortic arch hypoplasia was 0.39-0.64 (0.52 +/- 0.04) in isolated and 0.15-0.47 (0.34 +/- 0.06) in complex coarctation (p < 0.05). Left subclavian flap aortoplasty was used in 72 patients; alone in 25, in combination with pulmonary artery banding in 43 patients, and simultaneously with intracardiac repair in 4 patients. Extensive reconstruction of aortic arch and coarctation with synthetic patch was performed in the remaining 5 patients (AR/AO = 0.16 +/- 0.03) using cardiopulmonary by-pass at the time of intracardiac repair. Operative mortality was 2/76 (2.5%). Follow-up is 6.6 +/- 1.4 years. Recoarctation occurred in 3 patients (4%). AR/AA increased to 0.86 +/- 0.1 in isolated (p < 0.05 vs preoperative) and to 0.7 +/- 0.1 in complex coarctation (p < 0.05 vs preoperative). In the majority of cases, hypoplastic aortic arch associated with coarctation grows satisfactorily following simple repair of coarctation with no significant residual narrowing.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Planning and Analysis of an Arched Indoor Stadium

    Directory of Open Access Journals (Sweden)

    Alice T V

    2014-04-01

    Full Text Available This paper deals with planning and designing of a multilevel indoor stadium with hanging table tennis court and Olympic standard swimming pool. In order to support the large span the stadium is designed as an arched structure. The materials for the construction are chosen so as to have a minimum carbon di-oxide foot print. Static and earthquake analysis were done by using STAAD.Pro V8i. The paper also does a comparison between arched structure and plane frame structure.

  11. The shortened dental arch: a review of the literature.

    Science.gov (United States)

    Armellini, Debora; von Fraunhofer, J Anthony

    2004-12-01

    The functional demands of patients are highly variable and individual, requiring dental treatment to be tailored to the individual's needs and adaptive capability. The World Health Organization indicates that a functional, esthetic, natural dentition has at least 20 teeth, while the literature indicates that dental arches comprising the anterior and premolar regions meet the requirements of a functional dentition. The English-language peer-reviewed literature pertaining to the short dental arch (SDA) was identified through the Medline search engine covering the period between 1966 and the present and critically reviewed. This treatment option for the partially dentate patient may provide oral functionality, improved oral hygiene, comfort, and, possibly, reduced costs.

  12. Stabilization of medial longitudinal foot arch by peroneus longus transfer.

    Science.gov (United States)

    Lui, T H

    2016-06-01

    The mechanical integrity of the medial longitudinal arch depends on the dynamic support of muscles and the static support of ligaments. Although the posterior tibial tendon is the main dynamic stabilizer of the arch, the static structures provide the most support especially while the person is standing. After rupture of the posterior tibial tendon, the spring ligament may be compromised under increased stress and leads to talar derotation and peritalar subluxation. Surgical repair of the spring ligament has become an important adjunct to treating posterior tibial tendon abnormalities. A technique of peroneus longus transfer to augment the static stabilizers of the medial column is described in this article. PMID:27058034

  13. 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.

  14. Aortic arch in neonates with esophageal atresia: Preoperative assessment using CT

    Energy Technology Data Exchange (ETDEWEB)

    Day, D.L.

    1985-04-01

    Preoperative localization of the aortic arch is important in infants with esophageal atresia to prevent morbidity and death from an ipsilateral surgical approach. Computed tomography is an accurate, noninvasive technique for determining the position of the aortic arch.

  15. The surgical importance of an axillary arch in sentinel node biopsy.

    LENUS (Irish Health Repository)

    Ridgway, P F

    2011-03-01

    When Carl Langer described the aberrant axillary arch in 1846 its relevance in sentinel node biopsy (SNB) surgery could not have been contemplated. The authors define an incidence and elucidate relevance of the arch in SNB of the axilla.

  16. Influence of space of double row piles on soil arching effect

    Directory of Open Access Journals (Sweden)

    Zhao bo

    2015-02-01

    Full Text Available FLAC3d software, based on continuous theory, is used to analysis influence of space of double row piles on soil arching effect. The result shows that different from single row pile, double row piles will produce soil arching effect at front pile and rear pile severally, this phenomenon is called multiple soil arching effect; the residual load of front of front row pile will increase,the soil arch zone and the soil arching effect will decrease with the continuous increase of double row pile spacing.At the same time the soil arching effect of rear pile decreases, while the soil arching effect of front pile increases and finally the soil arching effect between front pile and rear pile will be equal.

  17. Rock-Arch Instability Characteristics of the Sandstone Plate under Different Loading Conditions

    OpenAIRE

    Shuren Wang; Paul Hagan; Baowen Hu; Kanchana Gamage; Cheng Yan; Dianfu Xu

    2014-01-01

    Under the concentrated loading and the uniform loading, the tests on the brittle fracture and the hinged arching until the rock-arch instability of the sandstone plate were conducted using self-developed loading device, and the sensitivity of influent factors on the rock-arch failure was analyzed by numerical test based on the particle flow code (PFC). The results showed that sandstone plate instability presented four phases: small deformation elastic stage, brittle fracture arching stage, ...

  18. A secondary analysis to determine variations of dental arch measurements with age and gender among Ugandans

    OpenAIRE

    Okori, Hilda; Apolot, Pricilla S.; Mwaka, Erisa; Tumusiime, Gerald; Buwembo, William; Munabi, Ian G.

    2015-01-01

    Background Dental arch dimensions are useful in dental practice and in forensic odontology. Local data is essential because ethnic differences exist in dental arch dimensions. In the Ugandan population no studies had been done on dental arch dimensions. The objective of the current study was to determine the variations in dental arch dimensions with age and gender in a sample of dental casts from the Ugandan population. Method This was a secondary analysis of dental casts previously prepared ...

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2014-01-01

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

  1. Comparison of arch forms between Korean and North American white populations.

    Science.gov (United States)

    Kook, Yoon-Ah; Nojima, Kunihiko; Moon, Hong-Beom; McLaughlin, Richard P; Sinclair, Peter M

    2004-12-01

    The purpose of this study was to evaluate morphologic differences in the mandibular arches of Korean and North American white subjects. The subjects were grouped according to arch form (tapered, ovoid, and square) to compare the frequency distribution of the 3 arch forms between the ethnic groups in each Angle classification. The sample included 160 white (60 Class I, 50 Class II, and 50 Class III) and 368 Korean (114 Class I, 119 Class II, and 135 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth according to mandibular tooth thickness data, and then 4 linear and 2 proportional measurements were taken. Arch width was statistically significantly smaller in the white group than in the Korean group, but arch depth did not differ. In the Korean group, the most frequent arch form was square, whereas in the white group the tapered arch form predominated. When the subjects were regrouped by arch form, the Korean arches had a tendency to be larger and deeper than the white arches within each of the 3 arch form types. PMID:15592215

  2. 49 CFR 230.61 - Arch tubes, water bar tubes, circulators and thermic siphons.

    Science.gov (United States)

    2010-10-01

    ... MAINTENANCE STANDARDS Boilers and Appurtenances Washing Boilers § 230.61 Arch tubes, water bar tubes, circulators and thermic siphons. (a) Frequency of cleaning. Each time the boiler is washed, arch tubes and... 49 Transportation 4 2010-10-01 2010-10-01 false Arch tubes, water bar tubes, circulators...

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  6. Double aortic arches, esophageal atresia and tracheal compression

    OpenAIRE

    Majid Yameen; Warade Monali; Aziz Zarina; Karthik G

    2009-01-01

    We report a case of double aortic arch in a 12-month-old male infant well delineated on 64 slice computed tomography scan. It formed a complete vascular ring around the trachea compressing it. The symptoms resolved after surgical division of the ring.

  7. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    Science.gov (United States)

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-06-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems.

  8. Athenry Castle, exterior east wall, door, jamb and arch

    OpenAIRE

    O'Donovan, Danielle

    2001-01-01

    Jamb and arch of pointed door that might be called Transitional or Early English in style. The mouldings perhaps too large and simple to be Early English. Moulding comprises: angle roll flanked at either side by quarter roll, and to front face by hollow chamfer.

  9. Dental arch diameters and relationships to oral habits.

    Science.gov (United States)

    Aznar, T; Galán, A F; Marín, I; Domínguez, A

    2006-05-01

    The objective was to analyze variations in dental arch width in relation to oral habits. Maxillary and mandibular intercanine and intermolar distance were determined in relation to certain oral habits in 1297 children (ages 3 to 6 years). After an oral examination, the parents of each child completed a questionnaire about oral habits, including the use of a dummy or a bottle (or both), finger sucking, mouth breathing, breast- or bottle-feeding, and duration of these habits. Data were subjected to statistical analysis by the chi-square test for qualitative variables and analysis of variance for quantitative variables with homogeneous variances. Statistical significance was P oral habits, the maxillary intercanine distance was less in children who used a dummy, especially one of a round design (P = .003). The maxillary intercanine distance was also less in children who breathed through their mouth (P = .002). In most cases, dummy use and mouth breathing were associated with a reduction in the intercanine distance in the maxillary arch. A dummy habit leads to a reduction in maxillary arch width, and mouth breathing causes a reduction in the size of both arches.

  10. How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

    Directory of Open Access Journals (Sweden)

    Andreas Habertheuer

    2015-01-01

    Full Text Available Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP and retrograde cerebral perfusion (RCP. Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data.

  11. UNILATERAL INCOMPLETE SUPERFICIAL PALMAR ARCH: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Subhankar Chakraborty

    2015-12-01

    Full Text Available The functional importance of hand is revealed by its rich vascularity contributed by superficial and deep palmar arches (SPA and DPA.Superficial palmar arch is located superficial to flexor tendons, and deep palmar arch deep to lumbrical muscles. Variations are found more often in SPA than DPA, later being more or less constant. During routine undergraduate dissection, we observed, unilateral incomplete SPA being formed by superficial palmar branches of ulnar and radial artery in the right hand of a male cadaver. These two arteries remained independent without anastomosis forming incomplete arch (SPA.The superficial branch of ulnar artery entered hand superficial to flexor retinaculum and supplied middle, ring and little finger by three branches. The superficial branch of radial artery via its two branches supplied index finger and thumb. Classical SPA formation was seen on left side. The presence of an incomplete SPA as in this case is a potential danger in RA harvesting for CABG.Variations in SPA play a pivotal role in microvascular surgical procedures of hand, RAinterventions and arterial graft applications.

  12. Strengthening of certain types of arch dams at broad sites

    Energy Technology Data Exchange (ETDEWEB)

    Kaganov, G. M.; Volkov, V. I.; Uchevatkin, A. A. [FGOU VPO Moscow State University of the Natural Environment (Russian Federation)

    2012-01-15

    The problem of strengthening defective and damaged arch dams is formulated, and methodical calculations are performed to substantiate a set of structural and production measures permitting substantial improvement in the stress-strain state and an increase in the safety factor of the structure. Feasibility of practical implementation of the results is foreseen.

  13. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography.

    Science.gov (United States)

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems.

  14. Bare Metal Stenting for Endovascular Exclusion of Aortic Arch Thrombi

    Energy Technology Data Exchange (ETDEWEB)

    Mahnken, Andreas H., E-mail: mahnken@med.uni-marburg.de [University Hospital Giessen and Marburg, Philipps University of Marburg, Department of Diagnostic Radiology (Germany); Hoffman, Andras; Autschbach, Ruediger; Damberg, Anneke L. M., E-mail: anneke.damberg@rwth-aachen.de [University Hospital RWTH Aachen, Department of Thoracic, Cardiac and Vascular Surgery (Germany)

    2013-08-01

    BackgroundAortic thrombi in the ascending aorta or aortic arch are rare but are associated with a relevant risk of major stroke or distal embolization. Although stent grafting is commonly used as a treatment option in the descending aorta, only a few case reports discuss stenting of the aortic arch for the treatment of a thrombus. The use of bare metal stents in this setting has not yet been described.MethodsWe report two cases of ascending and aortic arch thrombus that were treated by covering the thrombus with an uncovered stent. Both procedures were performed under local anesthesia via a femoral approach. A femoral cutdown was used in one case, and a total percutaneous insertion was possible in the second case.ResultsBoth procedures were successfully performed without any periprocedural complications. Postoperative recovery was uneventful. In both cases, no late complications or recurrent embolization occurred at midterm follow-up, and control CT angiography at 1 respectively 10 months revealed no stent migration, freely perfused supra-aortic branches, and no thrombus recurrence.ConclusionTreating symptomatic thrombi in the ascending aorta or aortic arch with a bare metal stent is feasible. This technique could constitute a minimally invasive alternative to a surgical intervention or complex endovascular therapy with fenestrated or branched stent grafts.

  15. Visualization of soil arching in flexible piled embankments

    Indian Academy of Sciences (India)

    Tuğba Eskışar

    2015-10-01

    Piled embankments rely on soil arching, but, when geogrid reinforcements are used, membrane action within the reinforcement contributes to load distribution. The arching of soil in unreinforced and reinforced piled embankments is evaluated in this study. A small-scale test apparatus is used to model the settlement up to 5 mm in an embankment with four pile elements. Visual inspection of the soil settlement and soil-reinforcement interaction is important to explain the mechanism of arching. In this study, X-ray Computed Tomography (CT) method was used as a non-destructive technique. The arching of soil between the piles was observed in the case of rigid piles and in the case of flexible piles with grid type of reinforcement. The load carrying capacity increased up to 33% in the case of geogrid reinforcement, and the differential settlement decreased around 35%, proving the efficiency of piled embankments with geogrid reinforcements. It is also shown that, using X-ray CT method and visualization techniques provides a better understanding of soil behavior in a reinforced embankment with the flexible pile foundation system.

  16. Arch of opportunity : Peace country operators expand, undeterred by vandalism

    Energy Technology Data Exchange (ETDEWEB)

    Jaremko, D.

    2006-01-15

    Activity levels in the Peace River Arch (Para) area of northwest Alberta are continuing despite reports of oilfield vandalism. Devon Energy is continuing its development of the 2 trillion cubic feet of original gas in place in the Dunevegan field and is also planning activities in the Triassic halfway formation in the southwest Arch. At depths between 2500 and 2800 metres, initial gas-flow rates from sour wells range from 2 to 5 million cubic feet per day. Devon is also targeting medium gravity oil in the northwest arch, and light gravity oil in the eastern part of the PRA. EnCana is expected to exit 2005 with production of 350 MMcf of gas equivalent per day from the PRA after having drilled more than 200 wells. A number of juniors are also expressing interest in the area. Galleon Energy has increased its focus in the PRA to 9000 barrels of oil equivalent per day and has separated its strategy into 4 areas: multi-zone drilling; a tight gas resource play; light, sweet crude development; and deep exploration in the arch's southwest corner. Talisman Energy has 4 rigs working in the area and plans to spend $168 million in the Grande Prairie area, with plans to drill 85 wells. Details of the Peace Arch Operators Group were provided, who meet with regulatory bodies like the Alberta Energy and Utilities Board (EUB), Alberta Environment, regional governments and the RCMP. A rash of oilfield sabotage in the late 1990s led to notoriety for the area. In October 2005, more sabotage occurred near a drilling rig. Satellite connected, web-interface cameras were installed by Anadarko, the rig's owner. Most people in the area are in favour of development, since oil and gas activity in the area will lead to economic benefits for the region. 3 figs.

  17. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    Directory of Open Access Journals (Sweden)

    EIGBEONAN Andrew B.

    2013-01-01

    Full Text Available The aim of this paper is to search and find methods of fostering creativity or ideas relating to creativity in teaching the arch-design studio. Teaching creativity through its methods will be making the students grounded in designing with creativity ideas and therefore we can have professionals that design and build with satisfaction, safety and complementary. It means we can have real buildings and places that satisfy our clients, the society and in harmony with the environment. Although there are similarities in the curricula of training architects all over the world, but educators go about it in their own convenient and suitable ways and styles. The ideas of creativity have been part of architecture from the onset, but are not deligently applied and also not formally incorporated in the curricula of training. The topic is also very relevant and timely as arch-educators and other stakeholders are of the opinion that something has to be done to improve the ways and methods of training architects, especially the teaching of the arch-design studio with regards to creativity. Through exploration of literature and interviews (physical and telephone call this paper finds methods of stimulating creativity ideas in the teaching of arch-design studio. Some of the methods of motivating creativity found in teaching the arch-design studio are: analogy, metaphors, biomimicry, brainstorming, attribute listing, mental map, TRIZ, restrictions, charrette, browsing, excursions, focus groups, other peoples viewpoints, using crazy ideas, using experts, visualizing a goal, working with dreams and images and giving students design tools such as drawings CAD and model making.

  18. Three-dimensional stiffness of the carpal arch.

    Science.gov (United States)

    Gabra, Joseph N; Li, Zong-Ming

    2016-01-01

    The carpal arch of the wrist is formed by irregularly shaped carpal bones interconnected by numerous ligaments, resulting in complex structural mechanics. The purpose of this study was to determine the three-dimensional stiffness characteristics of the carpal arch using displacement perturbations. It was hypothesized that the carpal arch would exhibit an anisotropic stiffness behavior with principal directions that are oblique to the conventional anatomical axes. Eight (n=8) cadavers were used in this study. For each specimen, the hamate was fixed to a custom stationary apparatus. An instrumented robot arm applied three-dimensional displacement perturbations to the ridge of trapezium and corresponding reaction forces were collected. The displacement-force data were used to determine a three-dimensional stiffness matrix using least squares fitting. Eigendecomposition of the stiffness matrix was used to identify the magnitudes and directions of the principal stiffness components. The carpal arch structure exhibited anisotropic stiffness behaviors with a maximum principal stiffness of 16.4±4.6N/mm that was significantly larger than the other principal components of 3.1±0.9 and 2.6±0.5N/mm (p<0.001). The principal direction of the maximum stiffness was pronated within the cross section of the carpal tunnel which is accounted for by the stiff transverse ligaments that tightly bind distal carpal arch. The minimal principal stiffness is attributed to the less constraining articulation between the trapezium and scaphoid. This study provides advanced characterization of the wrist׳s three-dimensional structural stiffness for improved insight into wrist biomechanics, stability, and function. PMID:26617368

  19. Idea of Design Scheme of Oujiang Bridge in Wenzhou City%温州瓯江大桥设计方案构思

    Institute of Scientific and Technical Information of China (English)

    罗嗣碧; 唐方清; 孔祥升; 杨华振

    2012-01-01

    Based on city bridge landscape requirements, a basket-type arch bridge scheme and a self anchored suspension bridge are presented for Oujiang Bridge. The two schemes are good fusion bridge located in natural environment. The basket type arch bridge scheme and the self-anchored suspension bridge scheme are in the top three on the bridge design competition at the same time. The projects and its landscape effect are introduced to provide the references for the same types of bridge landscape design.%基于城市桥梁的景观要求,对瓯江大桥提出了提篮式拱桥方案和自锚式悬索桥方案,两种方案均能很好地融合桥位处的自然环境.提篮式拱桥方案和高低塔自锚式悬索桥方案同时进入本桥方案竞赛的前三名.介绍了此方案的构思及其景观效果,为同类型的桥梁景观设计提供借鉴及参考.

  20. Lucy's flat feet: the relationship between the ankle and rearfoot arching in early hominins.

    Directory of Open Access Journals (Sweden)

    Jeremy M DeSilva

    Full Text Available BACKGROUND: In the Plio-Pleistocene, the hominin foot evolved from a grasping appendage to a stiff, propulsive lever. Central to this transition was the development of the longitudinal arch, a structure that helps store elastic energy and stiffen the foot during bipedal locomotion. Direct evidence for arch evolution, however, has been somewhat elusive given the failure of soft-tissue to fossilize. Paleoanthropologists have relied on footprints and bony correlates of arch development, though little consensus has emerged as to when the arch evolved. METHODOLOGY/PRINCIPAL FINDINGS: Here, we present evidence from radiographs of modern humans (n = 261 that the set of the distal tibia in the sagittal plane, henceforth referred to as the tibial arch angle, is related to rearfoot arching. Non-human primates have a posteriorly directed tibial arch angle, while most humans have an anteriorly directed tibial arch angle. Those humans with a posteriorly directed tibial arch angle (8% have significantly lower talocalcaneal and talar declination angles, both measures of an asymptomatic flatfoot. Application of these results to the hominin fossil record reveals that a well developed rearfoot arch had evolved in Australopithecus afarensis. However, as in humans today, Australopithecus populations exhibited individual variation in foot morphology and arch development, and "Lucy" (A.L. 288-1, a 3.18 Myr-old female Australopithecus, likely possessed asymptomatic flat feet. Additional distal tibiae from the Plio-Pleistocene show variation in tibial arch angles, including two early Homo tibiae that also have slightly posteriorly directed tibial arch angles. CONCLUSIONS/SIGNIFICANCE: This study finds that the rearfoot arch was present in the genus Australopithecus. However, the female Australopithecus afarensis "Lucy" has an ankle morphology consistent with non-pathological flat-footedness. This study suggests that, as in humans today, there was variation in arch

  1. Concrete bridge prioritization system

    OpenAIRE

    Kesselring, Debbie Anne

    1995-01-01

    An alternative method of prioritization for concrete bridge maintenance, repair, and rehabilitation activities is required due to the inability of the current system to manage the increasing nmnber of aging concrete bridges. The Concrete Bridge Prioritization System was proposed because of its ability to address the critical technical parameters of safety and cost benefit in prioritization of funding and work allocation. The analysis includes four parts, service life assessment, s...

  2. Correlation between arch form and facial form: A cross sectional study

    Directory of Open Access Journals (Sweden)

    Sanjna Nayar

    2015-01-01

    Full Text Available Arch form is a key determinant in teeth position. Teeth selection and placement must be based on the functional and esthetic needs of the patient. Keeping in mind, the biomechanics involved with the prosthesis. The aim of the study was to evaluate the correlation between arch form and facial form. About 40 individuals in the age group of 20-25 years were involved in the study. The arch form and facial form were analyzed statistically to check for any correlation. It was found that, 63.63% of leptoprosophic individuals had squarish arch form while, 54.6% of mesoprosophic faces had ovoid arch form.

  3. The effect of clinical use and sterilization on selected orthodontic arch wires.

    Science.gov (United States)

    Smith, G A; von Fraunhofer, J A; Casey, G R

    1992-08-01

    The effect of clinical use and various sterilization/disinfection protocols on three types of nickel-titanium, and one type each of beta-titanium and stainless steel arch wire was evaluated. The sterilization/disinfection procedures included disinfection alone or in concert with steam autoclave, dry heat, or cold solution sterilization. No clinically significant differences were found between new and used arch wires. The direction of load application to the arch wire and the particular segment of arch wire tested was found to cause substantial differences in generated loads for certain arch wire types.

  4. 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....

  5. 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...

  6. 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.

  7. 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...

  8. The floating water bridge

    International Nuclear Information System (INIS)

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

  9. Antenatal evaluation of fetal interrupted aortic arch type B

    Directory of Open Access Journals (Sweden)

    Ali Babacan

    2015-06-01

    Full Text Available Interruption of the aortic arch (IAA is a rare, severe form of congenital heart defect characterized by complete anatomical discontinuity between two adjacent segments of the aortic arch. The data on the features and outcomes of fetal IAA are limited. Three anatomical types have been described according to the site of interruption. The current recommendations for screening on the obstetric fetal anomaly scan include identification of a 4-chamber view, all 4 valves, and the outflow tracts, all of which can appear to be normal to the ultrasonographer in fetuses with conotruncal anomalies. Although the identification of IAA on a prenatal echocardiogram can be challenging, a number of anatomic features can facilitate the diagnosis. We aim to present the features and outcome of a case of IAA type B referred to our centre in the light of literatures.

  10. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    OpenAIRE

    EIGBEONAN, Andrew B.

    2013-01-01

    The aim of this paper is to search and find methods of fostering creativity or ideas relating to creativity in teaching the arch-design studio. Teaching creativity through its methods will be making the students grounded in designing with creativity ideas and therefore we can have professionals that design and build with satisfaction, safety and complementary. It means we can have real buildings and places that satisfy our clients, the society and in harmony with the environment. Although the...

  11. A Review of Diseases of Aortic Arch: Diagnosis by CTA

    OpenAIRE

    S. Sabouri

    2007-01-01

    The noninvasive revolution in cardiovascular imaging has altered the diagnostic algorithm for all types of acquired and congenital cardiovascular disease. CT techniques are commonly used in the diagnosis of aortic arch and its major branch vessels as well as thoracic and abdominal aortic diseases. CT angiogra-phy combines with CT scans obtained detailed in-formation on precise morphology and extent of dis-ease. Studies were performed on an MDCT unit (4row GE light speed). In infants and small...

  12. Giant aortic arch aneurysm complicating Kawasaki′s disease

    OpenAIRE

    Kaouthar Hakim; Rafik Boussada; Lilia Chaker; Fatma Ouarda

    2014-01-01

    Kawasaki disease (KD) is a common acute vasculitis in pediatric population that usually involves small- and middle-sized arteries, commonly coronary arteries. Although the incidence and natural course of coronary aneurysms after KD are well documented in studies, related reports on peripheral arterial and aortic aneurysms are scarce. We report the occurrence of a giant aortic aneurysm involving the horizontal part of aortic arch in a 28-month-old boy diagnosed with KD. This complication was m...

  13. Quasi-MLE for quadratic ARCH model with long memory

    OpenAIRE

    Grublytė, Ieva; Surgailis, Donatas; Škarnulis, Andrius

    2015-01-01

    We discuss parametric quasi-maximum likelihood estimation for quadratic ARCH process with long memory introduced in Doukhan et al. (2015) and Grublyt\\.e and \\v{S}karnulis (2015) with conditional variance given by a strictly positive quadratic form of observable stationary sequence. We prove consistency and asymptotic normality of the corresponding QMLE estimates, including the estimate of long memory parameter $0< d < 1/2$. A simulation study of empirical MSE is included.

  14. MODELING EXCHANGE RATES USING ARCH FAMILY OF MODELS

    Directory of Open Access Journals (Sweden)

    Ştefan Cristian CIUCU

    2016-06-01

    Full Text Available In this study, after a brief literature review, the RON / EURO exchange rate time series over the 03.01.2005 - 05.02.2015 time period is analyzed. After checking the stationarity of the data - ARCH, GARCH, EGARCH and TARCH models will be developed and compared. Next the best model is chosen and the serial correlation and the Jarque-Bera test are further analyzed with various conclusions being drawn.

  15. The Randomized Shortened Dental Arch Study: Tooth Loss

    OpenAIRE

    Walter, M H; Weber, A; Marré, B; Gitt, I.; Gerß, J.; Hannak, W.; Hartmann, S.; Heydecke, G; Huppertz, J.; Jahn, F; Ludwig, A.; Mundt, T.; Kern, M; Klein, V; Pospiech, P.

    2010-01-01

    The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA ...

  16. Space maintainer effects on intercanine arch width and length.

    Science.gov (United States)

    Dincer, M; Haydar, S; Unsal, B; Turk, T

    1996-01-01

    In order to investigate the effects of space maintainers in intercanine arch width and length, twenty cases, characterized with the early loss of mandibular primary molars were selected and divided into two groups. The treatment group used removable space maintainers, while the other ten cases served as the control group. The first dental casts of the treatment and control groups were obtained when the primary canines were in the mouth. After the eruption of permanent canines second dental casts were obtained in both groups. Six measurements were made on the dental casts of each patient. No parameter was found to be statistically significant in the treatment group. In the control group the increase in intercanine arch width and perimeter were found to be statistically significant. Also the increase at the buccal and lingual bone measurements were found to be statistically significant. These results showed that space maintainers might cease the increase in intercanine arch width and length during the transition period between the primary and permanent canines.

  17. First and second branchial arch syndromes: multimodality approach

    Energy Technology Data Exchange (ETDEWEB)

    Senggen, Elodie; Laswed, Tarek; Meuwly, Jean-Yves; Maestre, Leonor Alamo; Meuli, Reto; Gudinchet, Francois [University Hospital of Lausanne, Radiology Department, Lausanne (Switzerland); Jaques, Bertrand [University Hospital of Lausanne, Department of Otorhinolaryngology, Lausanne (Switzerland)

    2011-05-15

    First and second branchial arch syndromes (BAS) manifest as combined tissue deficiencies and hypoplasias of the face, external ear, middle ear and maxillary and mandibular arches. They represent the second most common craniofacial malformation after cleft lip and palate. Extended knowledge of the embryology and anatomy of each branchial arch derivative is mandatory for the diagnosis and grading of different BAS lesions and in the follow-up of postoperative patients. In recent years, many new complex surgical approaches and procedures have been designed by maxillofacial surgeons to treat extensive maxillary, mandibular and external and internal ear deformations. The purpose of this review is to evaluate the role of different imaging modalities (orthopantomogram (OPG), lateral and posteroanterior cephalometric radiographs, CT and MRI) in the diagnosis of a wide spectrum of first and second BAS, including hemifacial microsomia, mandibulofacial dysostosis, branchio-oto-renal syndrome, Pierre Robin sequence and Nager acrofacial dysostosis. Additionally, we aim to emphasize the importance of the systematic use of a multimodality imaging approach to facilitate the precise grading of these syndromes, as well as the preoperative planning of different reconstructive surgical procedures and their follow-up during treatment. (orig.)

  18. C-arm guided closed reduction of zygomatic arch fracture

    Energy Technology Data Exchange (ETDEWEB)

    Eo, Yoon Ki; Lee, Dong Kun [College of Medicine, Wonkwang Univ., Iksan (Korea, Republic of); Kim, Jeong Sam; Jang, Young Il [Kwangyang College, Kwangyang (Korea, Republic of)

    1999-04-01

    The zygomatic arch is structurally protruded and is easily fractured. The classic management of zygomatic arch fracture has been mentioned the Keen, Lothrop, Dingman and Alling and threaded K-wire. All of the above methods have advantages and disadvantages. To minimize the disadvantages, we performed threaded K-wire for the first time using C-arm image intensifier. The subjects were 16 patients with Knight North group II (Zygomatic arch fracture). Among them the C-arm was used in 12 patients and the operator used sensitivity general method in 4 patients and confirmed the operation by mobile X-ray equipment. In conclusion, both groups were satisfied surgically and cosmetically. Using the C-arm, actual image at the time operation was clear and satisfied, the surrounding tissue damage was minimized and at was more accurately completed. The operation time was shortened by 30 to 60 minutes proving it to be an efficient method. We suggest though that further studies be needed to evaluate the radiation effect on these patients.

  19. Modelling autogenous expansion for magnesia concrete in arch dams

    Institute of Scientific and Technical Information of China (English)

    Feng JIN; Guoxin ZHANG; Xiaoqing LUO; Chuhan ZHANG

    2008-01-01

    Magnesia Concrete is a kind of expansive con-crete used in Chinese hydraulic engineering more and more widely. To evaluate the effects of autogenous expan-sion on the stresses of arch dams, a simple model of auto-genous expansion for Magnesia Concrete in dam engineering is presented. This model is based on three assumptions: 1) the total amount of autogenous expan-sion of Magnesia Concrete is related only to the properties of materials and mixing of concrete; 2) the autogenous expansion of Magnesia Concrete is irreversible due to the irreversibility of hydration reaction of Magnesia in the concrete; 3) the autogenous expansion strain rates of Magnesia Concrete bear a relation between temperature and residual Magnesia per unit volume of concrete. The model is verified by some experimental data of autogen-ous expansion of Magnesia Concrete and field-measured data of an arch dam in China. Embedded into finite ele-ment arch dam simulation software, this model is employed to simulate the effects of autogenous expansion of Magnesia Concrete in hydraulic engineering.

  20. The Foot’s Arch and the Energetics of Human Locomotion

    Science.gov (United States)

    Stearne, Sarah M.; McDonald, Kirsty A.; Alderson, Jacqueline A.; North, Ian; Oxnard, Charles E.; Rubenson, Jonas

    2016-01-01

    The energy-sparing spring theory of the foot’s arch has become central to interpretations of the foot’s mechanical function and evolution. Using a novel insole technique that restricted compression of the foot’s longitudinal arch, this study provides the first direct evidence that arch compression/recoil during locomotion contributes to lowering energy cost. Restricting arch compression near maximally (~80%) during moderate-speed (2.7 ms−1) level running increased metabolic cost by + 6.0% (p < 0.001, d = 0.67; unaffected by foot strike technique). A simple model shows that the metabolic energy saved by the arch is largely explained by the passive-elastic work it supplies that would otherwise be done by active muscle. Both experimental and model data confirm that it is the end-range of arch compression that dictates the energy-saving role of the arch. Restricting arch compression had no effect on the cost of walking or incline running (3°), commensurate with the smaller role of passive-elastic mechanics in these gaits. These findings substantiate the elastic energy-saving role of the longitudinal arch during running, and suggest that arch supports used in some footwear and orthotics may increase the cost of running. PMID:26783259

  1. Mechanics Evolution Characteristics Analysis of Pressure-arch in Fully-mechanized Mining Field

    Directory of Open Access Journals (Sweden)

    S.R. Wang

    2014-09-01

    Full Text Available Based on a practical engineering, the three-dimension computational model was built using FLAC3D under the fullymechanized mining condition. Considering four variation factors, such as the distance of mining advancing, the strength of the surrounding rock, the speed of mining advancing and the dip angle of the coal seam, the mechanics evolution characteristics of the pressure-arch were analyzed. The result showed that for the horizontal seam, the geometric shape of the pressure-arch varied from flat arch to round arch gradually and the height and thickness of the pressure-arch also increased; the maximum principal stress in the skewback also increased with the working face advancing. With the strength of the surrounding rock from soft to hard, the arch thickness reduced, and the arch loading decreased. To improve the mining speed can do some contributions to the stability of the pressure-arch in the mining field. With the increase of dip angle of the seam, the pressure-arch displayed an asymmetric shape, the vault was tilted and moved to the upward direction. At the same time, the thickness of the pressure-arch increased, and the stress concentration in the skewback tended to be further intensified.

  2. A STUDY ON SUPERFICIAL PALMAR ARCH AND IT’S VARIATIONS

    Directory of Open Access Journals (Sweden)

    Venkateswara Rao

    2015-03-01

    Full Text Available INTRODUCTION: Knowledge of the frequency of anatomical variations of arterial pattern of hand is crucial for safe and successful hand surgical approach, diagnostic and therapeutic procedures. The superficial pal mar arch is a major blood supply to the hand. Various ano malous patterns in the superficial arch of hand are reported. The superficial pal mar arch is formed predominantly by ulnar artery with a contribution from superficial branch of radial artery. OBSERVATIONS: Superficial palmar arch is dissected within the p alm and observed from its origin to termination. Variations in its origin, branches were observed. A classic superficial palmar arch was found in 10% [5/50]. O ut of dissected specimens complete arch found in 67% and incomplete arch was 33%. Incomplete arch is formed by ulnar artery alone. It supply four and half fingers and give five branches. Majority of arches is supplied by three and half fingers and gives four branches. DISCUSSION: Many attempts have been made to classify these variations. A complex cla ssification of superficial pal mar arch by Coleman & Anson [1961]. S ince then, many other classification have been suggested by different authors [Karlsson & N iechajev, 1982; al - Turk & Metcalf, 1984; Doscher et al. 1985; Ruengsakulrachh et al. 2001;] provi des simplest understanding of distribution of the arches. Although the classical pattern of the arch occurs in frequently, anatomical presence of a complete superficial palmar arch varies from 84% to 66% [Coleman & Anson]. This incidence was lower in the c urrent study and might be a reflection of sample size [52 hands]. The median artery was found in 10% of the hands, similar frequency to that reported by McCormack et al. [1953].

  3. 大跨度连续刚构柔性拱组合结构受力效应分析%Analysis of Force Effect of Long Span Hybrid Structure of Continuous Rigid-Frame and Flexible Arch

    Institute of Scientific and Technical Information of China (English)

    谌启发

    2012-01-01

    为研究大跨度连续刚构柔性拱组合结构受力效应,以宜万铁路宜昌长江大桥为背景,在总结该类结构体系特点的基础上,采用桥梁博士分析软件建立全桥平面有限元模型,对全桥桥面施加竖向均布荷载(二期恒载),分析拱梁内力、竖向荷载及跨中截面弯矩的分配;将该桥与孔跨组成及截面尺寸完全相同的连续刚构桥在恒、活载作用下的结构内力进行对比,分析组合结构的拱梁组合效应.分析结果表明:在竖向均布荷载作用下,连续刚构柔性拱组合结构跨中范围吊杆轴力增加较大;结构跨中截面总弯矩绝大部分已转化为拱肋压力与主梁拉力;与连续刚构相比,活载作用下,连续刚构柔性拱组合结构的主梁弯矩显著减小,结构刚度提高较大,柔性拱作用明显.%To study the force effect of the long span hybrid structure of continuous rigid-frame and flexible arch, the Yichang Changjiang River Bridge on Yichang-Wanzhou Railway was cited as example. On the basis of summarization of the characteristics of such type of the structure system, the analysis software Bridge Doctor was used to establish the planar finite element model for the whole bridge of the bridge, the vertical uniform load (the second phase dead load) was applied to the deck of the whole bridge and the distribution of internal forces, vertical load and midspan section bending moment of the arch and girder of the bridge was analyzed. The structural internal forces of the bridge under the action of static and dynamic loads were compared to those of a continuous rigid-frame bridge having completely the same span compositions and sectional dimensions and the effect of the hybrid structure of the arch and girder was analyzed. The results of the analysis demonstrate that under the action of the vertical uniform load, the increase of the hanger axial forces in the range of the midspan of the hybrid structure of the continuous rigid

  4. The Layout and Simulation of Logarithmic Spiral Double Curved Arch Dam Transverse Joints%The Layout and Simulation of Logarithmic Spiral Double Curved Arch Dam Transverse Joints

    Institute of Scientific and Technical Information of China (English)

    DU Ting-na; DU Qi-lu; HUI Yuan

    2011-01-01

    Because of its good condition with mechanics, logarithmic spiral double curve arch bam has been widely used in the practical engineering. The introduction of a new method in how to divide transverse joint in arch dam will be given and the further research of its calculation has been done. The C++ is used in electronic procedure and the 3D simulation has been finished with AutoCAD, which will provide the object model for computer simulation of the arch dam and the division of finite element mesh. Meanwhile, this method in dividing the transverse joint in arch dam also can be taken as the calculated basis for the design and calculation of arch dam, construction lofting and the calculation of the work amount.

  5. ARCHES: Advancing Research & Capacity in Hydrologic Education and Science

    Science.gov (United States)

    Milewski, A.; Fryar, A. E.; Durham, M. C.; Schroeder, P.; Agouridis, C.; Hanley, C.; Rotz, R. R.

    2013-12-01

    Educating young scientists and building capacity on a global scale is pivotal towards better understanding and managing our water resources. Based on this premise the ARCHES (Advancing Research & Capacity in Hydrologic Education and Science) program has been established. This abstract provides an overview of the program, links to access information, and describes the activities and outcomes of student participants from the Middle East and North Africa. The ARCHES program (http://arches.wrrs.uga.edu) is an integrated hydrologic education approach using online courses, field programs, and various hands-on workshops. The program aims to enable young scientists to effectively perform the high level research that will ultimately improve quality of life, enhance science-based decision making, and facilitate collaboration. Three broad, interlinked sets of activities are incorporated into the ARCHES program: (A1) the development of technical expertise, (A2) the development of professional contacts and skills, and (A3) outreach and long-term sustainability. The development of technical expertise (A1) is implemented through three progressive instructional sections. Section 1: Students were guided through a series of online lectures and exercises (Moodle: http://wrrs.uga.edu/moodle) covering three main topics (Remote Sensing, GIS, and Hydrologic Modeling). Section 2: Students participated in a hands-on workshop hosted at the University of Georgia's Water Resources and Remote Sensing Laboratory (WRRSL). Using ENVI, ArcGIS, and ArcSWAT, students completed a series of lectures and real-world applications (e.g., Development of Hydrologic Models). Section 3: Students participated in field studies (e.g., measurements of infiltration, recharge, streamflow, and water-quality parameters) conducted by U.S. partners and international collaborators in the participating countries. The development of professional contacts and skills (A2) was achieved through the promotion of networking

  6. 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

  7. Inspection and Numerical Analysis of an Ottoman Railway Bridge in Jordan

    Directory of Open Access Journals (Sweden)

    Amin H. Almasri

    2016-01-01

    Full Text Available The construction of bridges represents a big challenge, since they require enormous economic effort and specialized technical skills. Bridges were historically important as they help connecting people and thus diffusing cultures, sharing ideas, and providing the backbone of transportation networks. This study focuses on the inspection and structural analysis of a 20th-century Ottoman railway stone arched bridge located on the Hejaz railway network in Jordan. The bridge has a very important cultural heritage value which stems from its history. The bridge stone material was cut and tested to determine its strength, in order to be used in the analysis. The structural analysis was carried out to assess the structural condition of the bridge and its suitability for reuse. The study includes static analysis under gravity loads and seismic analysis under earthquake loads. Despite the existence of deterioration in the bridge body construction materials due to a combination of human and natural factors, the analysis results proved enough structural capability to sustain the imposed gravity loads, but not a strong earthquake.

  8. 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...

  9. Dermatoglyphic assessment in subjects with different dental arch forms: an appraisal.

    Science.gov (United States)

    Sachdeva, Shabina; Tripathi, Arvind; Kapoor, Pranav

    2014-09-01

    Successful rehabilitation of edentulous individuals involves selection and arrangement of artificial teeth in accordance with the patient's original arch form. Various criteria exist for harmonious tooth arrangement but none is accepted universally. Finger and palm prints are unique to an individual and once formed in the sixth week of intra-uterine life, remain constant thereafter. Since dental arches are also formed during the same prenatal period, it is believed that the similar genetic factors may be involved in formation of dental arches and dermal patterns. This study was conducted to identify the association if any between type of dental arch forms and type of dermatoglyphic patterns. If specific dermal characteristics exist in individuals with specific dental arch forms, dermatoglyphic assessment of long standing edentulous subjects may help identify the patients preexisting dental arch form and thus aid in proper tooth arrangement. Ninety dentulous subjects were categorized into three groups on the basis of dental arch form (square, tapering or ovoid) and their finger and palm prints were recorded. The type of fingertip patterns, distribution of palmar patterns, Total Finger Ridge Count and angle atd were assessed. Subjects with square arches demonstrated a significantly high frequency of loops and a large atd angle with palmar patterns being most frequent in I3 region. Subjects with tapering arches showed a high frequency of whorls, a small atd angle and greatest distribution of palmar patterns in I4 region. In ovoid arched subjects, loops were the most common and palmar patterns were mostly observed in I4. Since distinctive dermal patterns were observed in subjects with different dental arch forms, it is believed that dermatoglyphics may be used as a reliable tool for identifying original arch form in edentulous patients. PMID:25183912

  10. Gender identification and morphologic classification of tooth, arch and palatal forms in Saudi population

    OpenAIRE

    Mohammad, Aljanakh; Koralakunte, Pavankumar Ravi

    2015-01-01

    Aims: To determine various tooth form, arch form, and palatal form with gender identification between males and females of the Saudi population. Materials and Methods: Irreversible hydrocolloid impressions were made of the maxillary teeth of 100 dentate male and female subjects to obtain study casts. A standardized procedure was adopted to photograph the maxillary dental arches and the maxillary central incisors on the study casts taken from each subject. The outline form of tooth, arch, and ...

  11. Initial arch wires for alignment of crooked teeth with fixed orthodontic braces.

    LENUS (Irish Health Repository)

    Wang, Yan

    2010-01-01

    The initial arch wire is the first arch wire to be inserted into the fixed appliance at the beginning of orthodontic treatment and is used mainly for correcting crowding and rotations of teeth. With a number of orthodontic arch wires available for initial tooth alignment, it is important to understand which wire is most efficient, as well as which wires cause the least amount of root resorption and pain during the initial aligning stage of treatment.

  12. 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 Europ...

  13. [The form of the dental arch according to the Tweed-Merrifield philosophy: individualization and attempt at standardization].

    Science.gov (United States)

    Amm, E W; Bou-Serhal, J P

    2003-12-01

    A literature review reveals that changes from the initial arch form lead to a proportionate amount of subsequent relapse and that there is great variation among human arch forms. A persistent search for the ideal arch form is still going on. Many authors presented different techniques for its individualization. A new software ("Arch form generator") was developed to create the arch form following the Tweed-Merrifield concepts. The form and dimensions of 169 mandibular arches were evaluated along with Angle classification and facial type as variables. The reliability of the Ricketts pentamorphic arch forms was questioned and a new arch guide was developed as part of a trial for standardization. The Class III cases showed greater width and smaller cuspid depth when compared to the Class I and Class II cases. The hypodivergent cases showed greater width when compared to the hyperdivergent and normodivergent cases. There is no characteristic form for the human dental arch. PMID:15301362

  14. KD loop for increasing arch perimeter in cleft and noncleft cases.

    Science.gov (United States)

    Dholakia, Kartik D; Bhat, Shweta R

    2012-01-01

    One of the many indications for dental arch expansion in treating malocclusion is to achieve arch compatibility, especially in surgical cases with severe Bolton discrepancies or collapsed arches due to congenitally missing anterior teeth. These cases usually require expansion in both the sagittal and transverse plane to achieve normal arch compatibility. Arch compatibility can be achieved by either dentoalveolar or skeletal expansion or both. Orthodontically, dentoalveolar expansion can be achieved by means of expanded arch form, vertical loops, or an added assembly such as a quad helix or Ni-Ti expander from the palatal or lingual aspect of the arch. However, these modalities normally provide expansion along transverse plane. If any expansion along sagittal plane is required, then additional appliances such as TransForce or modifications in the appliance system (eg, a quad helix with extension on anterior teeth) are necessary. Vertical loops do overcome these drawbacks to a certain extent; however, at the expense of generating moments during preactivation, which may lead to tipping of segments adjacent to the loop and precludes its use for larger changes of arch dimension. This article describes a new loop design--the KD loop--that increases the arch perimeter by sagittal and transverse expansion without generating significant moments along vertical plane. PMID:22567644

  15. Congenital aortic arch anomalies: diagnosis using contrast enhanced magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    ZHU Ming; ZHONG Yu-min; LI Yu-hua; SUN Ai-min; JIN Biao

    2005-01-01

    @@ Congenital aortic arch anomalies occur most commonly in children. The disease can be classified into three types: ① obstructive congenital abnormalities, including coarctation of aorta (CoA) and interruption of aortic arch (IAA); ② non-obstructive congenital abnormalities, including double aortic arch and others; ③ congenital shunt abnormalities, including different types of patent ductus arteriosus (PDA). Management of patients with congenital aortic arch anomalies relies on imaging. Routine imaging modalities, such as conventional X-ray plain film and transthoracic echocardiography (TTE), have been recently complemented by magnetic resonance imaging (MRI).

  16. Ennis Franciscan Friary, eastern tomb niche, north nave wall, jamb and arch moulding

    OpenAIRE

    O'Donovan, Danielle

    2005-01-01

    Jamb and arch of tomb niche. From intrados moulding comprises: ogee, quadrant. Similar tomb niches can be found at Quin, Adare Franciscan, Adare Augustinian, Askeaton, Lislaughtin, Abbeydorney, Kilconnell.

  17. Study on Simplified Model Construction Method of Dumbbell Shape Steel Pipe Concrete Arch Rib%哑铃形钢管混凝土拱肋简化建模方法研究

    Institute of Scientific and Technical Information of China (English)

    唐必刚; 张小华; 彭益华

    2012-01-01

    As the main stress component of steel pipe concrete arch bridge, whether the model construction method of dumbbell shape steel pipe concrete arch rib is reasonable is very significant to the structural safety of the whole bridge.By using MIDAS software, the arti- cle made various simplified simulation of the dumbbell shape steel pipe concrete arch db, and compared the calculations based on these simplified model with those based on the plates and solid element models constructed by using ANSYS software, so as to study and discuss simplified model construction methods which are more reasonable and more applicable.%哑铃形钢管混凝土拱肋作为钢管混凝土拱桥的主要受力构件,其建模方法是否合理对全桥结构的安全性具有重要的意义。文章采用MIDAS软件,对哑铃形钢管混凝土拱肋进行了多种简化模拟,并将这些简化模型计算结果与运用AN—SYS软件建立的板、实体单元模型的计算结果进行了比较,以研究探讨较为合理适用的简化建模方法。

  18. Construction and Design of Post-Tensioned Pearl-Chain Bridges using SL-Technology

    DEFF Research Database (Denmark)

    Halding, Philip Skov

    2016-01-01

    a filling layer of lower stiffness above the arches to level the road surface. The present Ph.D. thesis is part of a larger development project about Pearl‐Chain Bridges funded by Innovationsfonden. The project also included another Ph.D. study about the developed materials used in Pearl‐Chain Bridges......, and numerical modelling. Despite of high levels of normal force in PC‐Bridges, the result showed that a Mesnager inspired hinge type had a response similar to what was predicted in the literature. A specially designed saddle bearing also had elastic and plastic rotational resistance, but this hinge type......) A test to fracture to observe the ductility in the system, and fracture type. The collapse occurred after two plastic hinges were formed in the 3/8, and 5/8 points of the span. Several warnings signs were observed when approaching the maximum loading....

  19. Vibration monitoring of long bridges and their expansion joints and seismic devices

    Directory of Open Access Journals (Sweden)

    Islami Kleidi

    2015-01-01

    Full Text Available This paper presents a number of recently installed Structural Health Monitoring (SHM systems: a on a 2km double suspension bridge; b on a long railway viaduct that has experienced cracking; and c on a steel arch bridge in a seismically active area. Damage detection techniques have been applied based on high-frequency measurements of vibrations, pressure and strain, enabling a proper understanding of the structures’ behaviour to be gained. The diverse range of applications presented, designed in collaboration with structure owners and design engineers, includes damage detection on expansion joints of suspension bridges, crack analysis and correlation with accelerations of high-speed trains, and high-frequency performance monitoring of seismic devices. These case studies, based on both static and dynamic approaches, demonstrate the usefulness and ease of use of such systems, and the enormous gains in efficiency they offer.

  20. Integral Abutment and Jointless Bridges

    OpenAIRE

    Cristian-Claudiu Comisu

    2005-01-01

    Integral bridges, or integral abutment and jointless bridges, as they are more commonly known in the USA, are constructed without any movement joints between spans or between spans and abutments. Typically these bridges have stub-type abutments supported on piles and continuous bridge deck from one embankment to the other. Foundations are usually designed to be small and flexible to facilitate horizontal movement or rocking of the support. Integrally bridges are simple or multiple span ones t...

  1. Earthquake safety assessment of concrete arch and gravity dams

    Institute of Scientific and Technical Information of China (English)

    Lin Gao; Hu Zhiqiang

    2005-01-01

    Based on research studies currently being carried out at Dalian University of Technology, some important aspects for the earthquake safety assessment of concrete dams are reviewed and discussed. First, the rate-dependent behavior of concrete subjected to earthquake loading is examined, emphasizing the properties of concrete under cyclic and biaxial loading conditions. Second, a modified four-parameter Hsieh-Ting-Chen viscoplastic consistency model is developed to simulate the rate-dependent behavior of concrete. The earthquake response of a 278m high arch dam is analyzed, and the results show that the strain-rate effects become noticeable in the inelastic range. Third, a more accurate non-smooth Newton algorithm for the solution of three-dimensional frictional contact problems is developed to study the joint opening effects of arch dams during strong earthquakes. Such effects on two nearly 300m high arch dams have been studied. It was found that the canyon shape has great influence on the magnitude and distribution of the joint opening along the dam axis. Fourth, the scaled boundary finite element method presented by Song and Wolf is employed to study the dam-reservoir-foundation interaction effects of concrete dams. Particular emphases were placed on the variation of foundation stiffness and the anisotropic behavior of the foundation material on the dynamic response of concrete dams. Finally, nonlinear modeling of concrete to study the damage evolution of concrete dams during strong earthquakes is discussed. An elastic-damage mechanics approach for damage prediction of concrete gravity dams is described as an example. These findings are helpful in understanding the dynamic behavior of concrete dams and promoting the improvement of seismic safety assessment methods.

  2. Two ARCH Models and Their Limitations as Diffusion Processes

    Institute of Scientific and Technical Information of China (English)

    杨海波; 叶俊

    2002-01-01

    Two typical ARCH models: the ASDARCH model and the APARCH model are analyzed. Let Yk and σ2k denote the log returns and the volatility. When the time interval h goes to zero, (Yk,σ2k), as a discrete time Markov chain system, weakly converges to a continuous time diffusion process. The continuous time approximation of the ASDARCH model is done using two different methods. With some transformation, these two results are equivalent to high frequency data. The continuous time approximation of the APARCH model is obtained by a different procedure.

  3. On monolithic stability and reinforcement analysis of high arch dams

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Monolithic stability safety and reinforcement based on monolithic stability are very important for arch dam design.In this paper,the issue is addressed based on deformation reinforcement theory.In this approach,plastic complementary energy norm can be taken as safety Index for monolithic stability.According to deformation reinforcement theory,the areas where unbalanced force exists require reinforcement,and the required reinforcement forces are just the unbalanced forces with opposite direction.Results show that areas with unbalanced force mainly concentrate in dam-toes,dam-heels and faults.

  4. Design for Huaxi Bridge in Highway around Guiyang City%贵阳环城高速公路花溪大桥设计

    Institute of Scientific and Technical Information of China (English)

    金令

    2012-01-01

    Huaxi Bridge is a super large bridge across above Huaxi reservoir in the south line of Guiyang City Highway. The main bridge, which is a 192 m half-through concrete-filled steel tube arch bridge with 29.3 m in full width ( bi-direction four lanes plus sidewalks) and 100 km/h design speed, is the key bridge and controlling project of the whole line. The author illustrates the general design situation of the bridge, including bridge-type selection, design parameters, structure details and construction methods. According to the situations at the bridge site, Huaxi Bridge is the first bridge using the technologies such as triangular space truss arch, cutting caisson foundation, self-compacting concrete-filled steel tube in Guizhou region, which can give some references for the same type of bridge constructions in mountainous karst area.%花溪大桥为贵阳环城高速公路南环线跨越花溪水库的一座特大型桥梁,主桥为192 m的中承式钢管混凝土拱桥,大桥全宽29.3 m(双向四车道+人行道),设计速度100 km/h,是全线重点桥梁和控制性工程.介绍该桥的总体设计情况,包括桥式选择、设计参数、构造细节、施工方法.根据桥址处的条件大桥在贵州地区首次采用了三角形空间桁架拱、挖井基础、自密实钢管混凝土等技术,对多山岩溶地区同类型桥梁建设具有参考意义.

  5. Narrowing carpal arch width to increase cross-sectional area of carpal tunnel – a cadaveric study

    Science.gov (United States)

    Li, Zong-Ming; Gabra, Joseph N.; Marquardt, Tamara L.; Kim, Dong Hee

    2013-01-01

    Background Carpal tunnel morphology plays an essential role in the etiology and treatment of carpal tunnel syndrome. The purpose of this study was to observe the morphological changes of the carpal tunnel as a result of carpal arch width narrowing. It was hypothesized carpal arch width narrowing would result in increased height and area of the carpal arch. Methods The carpal arch width of eight cadaveric hands was narrowed by a custom apparatus and cross-sectional ultrasound images were acquired. The carpal arch height and area were quantified as the carpal arch width was narrowed. Correlation and regression analyses were performed for the carpal arch height and area with respect to the carpal arch width. Findings The carpal tunnel became more convex as the carpal arch width was narrowed. The initial carpal arch width, height, and area were 25.7 (SD 1.9) mm, 4.1 (SD 0.6) mm, and 68.5 (SD 14.0) mm2, respectively. The carpal arch height and area negatively correlated with the carpal arch width, with correlation coefficients of −0.974 (SD 0.018) and −0.925 (SD 0.034), respectively. Linear regression analyses showed a 1 mm narrowing of the carpal arch width resulted in proportional increases of 0.40 (SD 0.14) mm in the carpal arch height and 4.0 (SD 2.2) mm2 in the carpal arch area. Interpretation This study demonstrates that carpal arch width narrowing leads to increased carpal arch height and area, a potential mechanism to reduce the mechanical insult to the median nerve and relieve symptoms associated with carpal tunnel syndrome. PMID:23583095

  6. Building problem solving environments with the arches framework

    Energy Technology Data Exchange (ETDEWEB)

    Debardeleben, Nathan [Los Alamos National Laboratory; Sass, Ron [U NORTH CAROLINA; Stanzione, Jr., Daniel [ASU; Ligon, Ill, Walter [CLEMSON UNIV

    2009-01-01

    The computational problems that scientists face are rapidly escalating in size and scope. Moreover, the computer systems used to solve these problems are becoming significantly more complex than the familiar, well-understood sequential model on their desktops. While it is possible to re-train scientists to use emerging high-performance computing (HPC) models, it is much more effective to provide them with a higher-level programming environment that has been specialized to their particular domain. By fostering interaction between HPC specialists and the domain scientists, problem-solving environments (PSEs) provide a collaborative environment. A PSE environment allows scientists to focus on expressing their computational problem while the PSE and associated tools support mapping that domain-specific problem to a high-performance computing system. This article describes Arches, an object-oriented framework for building domain-specific PSEs. The framework was designed to support a wide range of problem domains and to be extensible to support very different high-performance computing targets. To demonstrate this flexibility, two PSEs have been developed from the Arches framework to solve problem in two different domains and target very different computing platforms. The Coven PSE supports parallel applications that require large-scale parallelism found in cost-effective Beowulf clusters. In contrast, RCADE targets FPGA-based reconfigurable computing and was originally designed to aid NASA Earth scientists studying satellite instrument data.

  7. archAR: an archaeological augmented reality experience

    Science.gov (United States)

    Wiley, Bridgette; Schulze, Jürgen P.

    2015-03-01

    We present an application for Android phones or tablets called "archAR" that uses augmented reality as an alternative, portable way of viewing archaeological information from UCSD's Levantine Archaeology Laboratory. archAR provides a unique experience of flying through an archaeological dig site in the Levantine area and exploring the artifacts uncovered there. Using a Google Nexus tablet and Qualcomm's Vuforia API, we use an image target as a map and overlay a three-dimensional model of the dig site onto it, augmenting reality such that we are able to interact with the plotted artifacts. The user can physically move the Android device around the image target and see the dig site model from any perspective. The user can also move the device closer to the model in order to "zoom" into the view of a particular section of the model and its associated artifacts. This is especially useful, as the dig site model and the collection of artifacts are very detailed. The artifacts are plotted as points, colored by type. The user can touch the virtual points to trigger a popup information window that contains details of the artifact, such as photographs, material descriptions, and more.

  8. Design and construction of prestressed arch using plastic shoppers waste

    Directory of Open Access Journals (Sweden)

    Ali Khan, S.

    2012-12-01

    Full Text Available Since the development of plastic in the last century, being versitile it has become very popular for diversified uses. The problem appears when these plastics, particularly shoppers are disposed as waste. The current reuse and recycling rates for the plastic shoppers waste are very low. Construction Industry has a great potential for the reuse of shoppers waste. Shoppers waste has been compressed to fabricate compressed shoppers waste (CSW blocks. This study is related to an innovative reuse of CSW-blocks for the construction of prestressed structural arch. This paper is dedicated to the design and construction of structural arch using shoppers waste as a material.

    Desde su desarrollo durante el siglo pasado y debido a su versatilidad, el plástico se ha hecho ubicuo en la sociedad actual. Los problemas surgen cuando este material, sobre todo cuando conforma bienes de consumo, se desecha. Actualmente, los índices de valorización y reciclado de residuos plásticos de origen doméstico son muy bajos. El sector de la construcción tiene una enorme potencial para reutilizar este tipo de residuos, que se pueden comprimir para fabricar bloques. Este artículo presenta un uso innovador de los bloques de residuos plásticos: la construcción de un arco estructural pretesado. Describe el proyecto y la ejecución de un arco estructural construido con estos materiales de desecho.

  9. Micron narrowband adaptive optics imaging in the arches cluster

    CERN Document Server

    Blum, R D; Pasquali, A; Heydari-Malayeri, M; Conti, P S; Schmutz, W

    2001-01-01

    Canada-France-Hawaii-Telescope adaptive optics bonnette images through narrow-band filters in the $K-$band are presented for the Arches cluster. Continuum fluxes, line fluxes, and equivalent widths are derived from high angular resolution images, some near diffraction limited, for the well known massive stars in the Arches cluster. Images were obtained in the lines of \\ion{He}{1} 2.06 \\mic, \\ion{H}{1} Br$\\gamma$ (2.17 \\mic), and \\ion{He}{2} 2.19 \\mic as well as continuum positions at 2.03 \\mic, 2.14 \\mic, and 2.26 \\mic. In addition, fluxes are presented for \\ion{H}{1} P$\\alpha$ (1.87 \\mic) and a nearby continuum position (1.90 \\mic) from Hubble Space Telescope archival data. The 2 \\mic and P$\\alpha$ data reveal two new emission-line stars and three fainter candidate emission-line objects. Indications for a spectral change of one object between earlier observations in 1992/1993 and our data from 1999 are found. The ratio of \\ion{He}{2} 2.19 \\mic to Br$\\gamma$ emission exhibits a narrow distribution among the s...

  10. THE EVOLUTION OF PROTOPLANETARY DISKS IN THE ARCHES CLUSTER

    International Nuclear Information System (INIS)

    Most stars form in a cluster environment. These stars are initially surrounded by disks from which potentially planetary systems form. Of all cluster environments, starburst clusters are probably the most hostile for planetary systems in our Galaxy. The intense stellar radiation and extreme density favor rapid destruction of circumstellar disks via photoevaporation and stellar encounters. Evolving a virialized model of the Arches cluster in the Galactic tidal field, we investigate the effect of stellar encounters on circumstellar disks in a prototypical starburst cluster. Despite its proximity to the deep gravitational potential of the Galactic center, only a moderate fraction of members escapes to form an extended pair of tidal tails. Our simulations show that encounters destroy one-third of the circumstellar disks in the cluster core within the first 2.5 Myr of evolution, preferentially affecting the least and most massive stars. A small fraction of these events causes rapid ejection and the formation of a weaker second pair of tidal tails that is overpopulated by disk-poor stars. Two predictions arise from our study. (1) If not destroyed by photoevaporation protoplanetary disks of massive late B- and early O-type stars represent the most likely hosts of planet formation in starburst clusters. (2) Multi-epoch K- and L-band photometry of the Arches cluster would provide the kinematically selected membership sample required to detect the additional pair of disk-poor tidal tails.

  11. Behaviour of Steel Arch Stabilized by a Textile Membrane

    Science.gov (United States)

    Svoboda, O.; Machacek, J.

    2015-11-01

    Behaviour of the slender steel arch supporting textile membranes in a membrane structure with respect to in-plane and out-of plane stability is investigated in the paper. In the last decades the textile membranes have been widely used to cover both common and exclusive structures due to progress in new membrane materials with eminent properties. Nevertheless, complex analysis of such membranes in interaction with steel structure (carbon/stainless steel perimeter or supporting elements) is rather demanding, even with specialized software. Laboratory model of a large membrane structure simulating a shelter roof of a concert stage was tested and the resulting stress/deflection values are presented. The model of a reasonable size was provided with prestressed membrane of PVC coated polyester fabric Ferrari® Précontraint 702S and tested under various loadings. The supporting steel structure consisted of two steel arch tubes from S355 grade steel and perimeter prestressed cables. The stability behaviour of the inner tube was the primary interest of the investigation. The SOFiSTiK software was used to analyse the structural behaviour in 3D. Numerical non-linear analysis of deflections and internal forces of the structure under symmetrical and asymmetrical loadings covers various membrane prestressing and specific boundary conditions. The numerical results are validated using test results. Finally, the preliminary recommendations for appropriate numerical modelling and stability design of the supporting structure are presented.

  12. Deformation reinforcement theory and its application to high arch dams

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,the deformation reinforcement theory(DRT) proposed by the authors is elaborated with a new definition of instability that an elasto-plastic structure is not stable if it cannot satisfy simultaneously equilibrium condition,kinematical admissibility and constitutive equations under the prescribed loading.Starting from the definition,a proof is established to the principle of minimum plastic complementary energy for failured structures.It is revealed that the principle of mini-mum plastic complementary energy results in relaxed constitutive equations,especially,yield conditions.It is demonstrated with case studies that many key issues in arch dam design,e.g.,global stability,dam-toe reinforcement,dam-toe cracking,dam-abut-ment reinforcement,can be well solved within the framework of the deformation reinforcement theory.The structural global stability can be described by the curve of the plastic complementary energy vs overloading factor.The unbalanced-forces obtained by elasto-plastic FEM can be used as the basis of analysis of global stability,dam-heel cracking,dam-toe anchorage and reinforcement of faults of high arch dams and their foundations.

  13. Designing light responsive bistable arches for rapid, remotely triggered actuation

    Science.gov (United States)

    Smith, Matthew L.; Shankar, M. Ravi; Backman, Ryan; Tondiglia, Vincent P.; Lee, Kyung Min; McConney, Michael E.; Wang, David H.; Tan, Loon-Seng; White, Timothy J.

    2014-03-01

    Light responsive azobenzene functionalized polymer networks enjoy several advantages as actuator candidates including the ability to be remotely triggered and the capacity for highly tunable control via light intensity, polarization, wavelength and material alignments. One signi cant challenge hindering these materials from being employed in applications is their often relatively slow actuation rates and low power densities, especially in the absence of photo-thermal e ects. One well known strategy employed in nature for increasing actuation rate and power output is the storage and quick release of elastic energy (e.g., the Venus ytrap). Using nature as inspiration we have conducted a series of experiments and developed an equilibrium mechanics model for investigating remotely triggered snap-through of bistable light responsive arches made from glassy azobenzene functionalized polymers. After brie y discussing experimental observations we consider in detail a geometrically exact, planar rod model of photomechanical snap-through. Theoretical energy release characteristics and unique strain eld pro les provide insight toward design strategies for improved actuator performance. The bistable light responsive arches presented here are potentially a powerful option for remotely triggered, rapid motion from apparently passive structures in applications such as binary optical switches and positioners, surfaces with morphing topologies, and impulse locomotion in micro or millimeter scale robotics.

  14. Evolution of magnetic topology of an erupting arched laboratory magnetoplasma

    Science.gov (United States)

    Tripathi, S.; Gekelman, W. N.

    2013-12-01

    Arched magnetoplasma structures ubiquitously exist in the solar atmosphere and affect energetic phenomena such as flares and coronal mass ejections. Presence of an electrical current in such structures generates a twisted magnetic-field and the term arched magnetic flux rope (AMFR) is used for them. In the limit of low electrical current (compared to the current-threshold for the kink instability), the magnetic twist in an AMFR becomes small and it resembles the structure of an arched magnetic flux tube. However, the term arched magnetic flux rope can be used for arched magnetoplasma structures without any loss of generality. We report results on the evolution of the magnetic topology of an erupting laboratory AMFR during its eruption. The AMFR (plasma β ≈ 10-3, Lundquist number ≈ 102-105, AMFR radius/ion-gyroradius ≈ 20, B ≈ 1000 Gauss at footpoints) is created using a lanthanum hexaboride (LaB6) plasma source and it evolves in an ambient magnetoplasma produced by another LaB6 source (See Ref. [2] for details of the experiment). The eruption is triggered by gradually increasing the electrical current in the AMFR and its evolution is captured by a fast-CCD camera. The relative magnitudes of the parameters of the AMFR and the ambient magnetoplasma can be varied to simulate a variety of conditions relevant to solar eruptions. The experiment runs continuously with a 0.5 Hz repetition rate. Hence, the plasma parameters of the AMFR are recorded with a good spatiotemporal resolution (spatial-resolution/AMFR-length ≈ 10-2 - 10-3, temporal-resolution/eruption-time ≈ 10-3) using computer-controlled movable probes. The three-dimensional magnetic-field of the AMFR is directly measured using a three-axis magnetic-loop probe. The pre-eruption phase of the AMFR remains quiescent for ≈ 100 Alfven transit times and the camera images evince a persistent appearance of the AMFR during this phase. In contrast, the post-eruption phase of the AMFR is associated with

  15. 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.

  16. Application of Automatic Submerged -arc Welding in Girth Welding of Arch Rib of Tube Arch%埋弧自动焊在钢管拱拱肋环焊缝中的应用

    Institute of Scientific and Technical Information of China (English)

    宇文德成; 张丽惠

    2011-01-01

    Research purposes: According to the structural characteristics of the arch rib of the steel tube of polygonal line (arc shape) , this paper tries to find out the negative factors which affect the welding position, speed changes and structural mass balance when joining the segment of arch rib into the polygonal line (Arc shape) during automatic submerged - arc welding, and offers the solution to the problem with kinematic analysis and calculation for making the processing of arch rib of steel tube in workshop fulfilled by submerged - arc welding.Research conclusions:Based on the theoretical analysis and according to the actual production process, the negative factors were overcome by determining the reasonable support location of roller and properly configuring weight equalizer. Based on it, a method to do girth welding of polygonal line tube with submerged - arc welding was found. With this method, the 100% of automatic welding of girth joint in factory workshop can be realized, which is up to 90% of the full - bridge tube girth joint with features of less welding defects, stable welding quality and improving welding efficiency.%研究目的:根据钢管拱折线(弧形)拱肋的结构特点,找出将拱肋节段对接成折线(弧形)时,影响采用埋弧自动焊时焊点位置、速度变化和结构质量平衡的不利因素.并通过运动学分析与计算,提出解决问题的方法.使钢管拱拱肋厂内加工全部实现采用埋弧自动焊工艺.研究结论:根据理论分析,在实际生产过程中,采取确定滚轮合理的支撑位置及适当配置平衡重物这两种措施,克服了不利因素,摸索出了一套在滚轮架上用自动埋弧焊工艺焊接折线管对接环焊缝的方法,实现了工厂内加工环焊缝100%的自动化焊接,占全桥所有管对接环焊缝的90%以上,焊缝缺陷频率低、质量稳定、提高了工效.

  17. The effect of minimal shoes on arch structure and intrinsic foot muscle strength

    Directory of Open Access Journals (Sweden)

    Elizabeth E. Miller

    2014-06-01

    Conclusion: These results suggest that endurance running in minimal support footwear with 4 mm offset or less makes greater use of the spring-like function of the longitudinal arch, thus leading to greater demands on the intrinsic muscles that support the arch, thereby strengthening the foot.

  18. Rock-Arch Instability Characteristics of the Sandstone Plate under Different Loading Conditions

    Directory of Open Access Journals (Sweden)

    Shuren Wang

    2014-01-01

    Full Text Available Under the concentrated loading and the uniform loading, the tests on the brittle fracture and the hinged arching until the rock-arch instability of the sandstone plate were conducted using self-developed loading device, and the sensitivity of influent factors on the rock-arch failure was analyzed by numerical test based on the particle flow code (PFC. The results showed that sandstone plate instability presented four phases: small deformation elastic stage, brittle fracture arching stage, rock-arch bearing stage, and rock-arch instability stage. Under the uniform loading, the maximum vertical force of the rock-arch instability was much higher than that under the concentrated loading condition, but the maximum lateral force was almost the same. The number of acoustic emission (AE and its positioning results of the sandstone plate showed that the extent of the plate damage under the uniform loading was higher than that under the concentrated loading condition. The friction coefficient effect, size effect, loading rate effect, and the initial horizontal force effect on the rock-arch instability were analyzed by the PFC3D numerical experiment.

  19. Clinical Advantages and Limitations of Monolithic Zirconia Restorations Full Arch Implant Supported Reconstruction: Case Series

    Directory of Open Access Journals (Sweden)

    Joao Carames

    2015-01-01

    Full Text Available Purpose. The purpose of this retrospective case series is to evaluate the clinical advantages and limitations of monolithic zirconia restorations for full arch implant supported restorations and report the rate of complications up to 2 years after insertion. Materials and Methods. Fourteen patients received implant placement for monolithic zirconia full arch reconstructions. Four implants were placed in seven arches, eleven arches received six implants, two arches received seven implants, two arches received eight implants, and one arch received nine implants. Results. No implant failures or complications were reported for an implant survival rate of 100% with follow-up ranging from 3 to 24 months. Conclusions. Monolithic zirconia CAD-/CAM-milled framework restorations are a treatment option for full arch restorations over implants, showing a 96% success rate in the present study. Some of the benefits are accuracy, reduced veneering porcelain, and minimal occlusal adjustments. The outcome of the present study showed high success in function, aesthetics, phonetics, and high patient satisfaction.

  20. Cephalic arch stenosis in autogenous brachiocephalic hemodialysis fistulas: results of cutting balloon angioplasty

    DEFF Research Database (Denmark)

    Heerwagen, Søren Thorup; Lönn, Lars; Schroeder, Torben V;

    2010-01-01

    Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose...... of this retrospective study was to report outcomes after cutting balloon angioplasty (CBA) of cephalic arch stenosis....

  1. "Roller coaster maneuver via lateral orbital approach" for reduction of isolated zygomatic arch fractures.

    Science.gov (United States)

    Pilanci, Ozgur; Basaran, Karaca; Datli, Asli; Kuvat, Samet Vasfi

    2013-11-01

    Numerous techniques have been reported for the reduction of zygomatic arch fractures. In this article, we aimed to describe a technique we named as "roller coaster maneuver via lateral orbital approach" to closed reduction of the isolated-type zygomatic arch fractures. Surgical outcomes of 14 patients treated with this method were outlined. PMID:24220411

  2. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

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

  3. Predictors of long-term stability of maxillary dental arch dimensions in patients treated with a transpalatal arch followed by fixed appliances

    OpenAIRE

    Raucci, Gaetana; Elyasi, Maryam; Pachêco-Pereira, Camila; Grassia, Vincenzo; d’Apuzzo, Fabrizia; Flores-Mir, Carlos; Perillo, Letizia

    2015-01-01

    Background The aim of this retrospective study was to identify which dental and/or cephalometric variables were predictors of long-term maxillary dental arch stability in patients treated with a transpalatal arch (TPA) during the mixed dentition phase followed by full fixed appliances in the permanent dentition. Methods Thirty-six patients, treated with TPA followed up by full fixed appliances, were divided into stable and relapse groups based on the long-term presence or not of relapse. Inte...

  4. 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.

  5. Analysis on the dynamic properties of Zhaoqing Xijiang Bridge%肇庆西江特大桥动力特性分析

    Institute of Scientific and Technical Information of China (English)

    翟建平

    2011-01-01

    Zhaoqing Xijiang Bridge on Nanning - Guangzhou Railway is a steel box x - style arch bridge with the largest span (450 meters) in China. Based on the construction drawings and structural characteristics, the spatial finite element model was established by ANSYS software, and the natural frequencies as well as vibration modes of the bridge were calculated with Lanbcos method. Besides, the influence of arch' s introverted inclination angle to the dynamic properties of long - span steel box x - style arch bridge was discussed, which could not merely act as the premise of health monitoring, wind stability analysis and seismic analysis, but also provide reference for the design as well as dynamic behavior of long - span steel box x - style arch bridge.%南广铁路肇庆西江特大桥为我国目前跨度最大(450 m)的钢箱提篮拱桥,根据大桥的结构特点,采用ANSYS建立了全桥空间有限元模型,利用分块兰卡斯方法计算了该桥的自振频率和振型,并探讨了拱肋内倾角对大跨度钢箱提篮拱桥动力特性的影响,可为该桥的健康监测、抗风和抗震分析提供前提条件和依据,并可为大跨度钢箱提篮拱桥的设计与动力特性研究提供参考.

  6. Dynamic stability analysis of circular arch subjected to follower forces with small disturbances; Judo kaju wo ukeru enkei arch no yuran ni yoru doteki kyodo to anteisei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Fukuchi, N.; Okada, K. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Hirano, Y. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1997-09-04

    This paper describes the deformation and dynamic stability of circular arch subjected to follower forces in a submerged membrane type marine structure reinforced by arch frames. Governing equations for finite deformations of the circular arch subjected to follower forces are introduced using an embedded curve coordinate, which are formulated by applying Galerkin method. In addition, equations of motion due to small disturbances under given condition of loading are introduced. Based on these equations, dynamic stability of the arch is analyzed by means of Runnge-Kutta-Gill method, to clarify the relationship between disturbances and instability regions and the resulting phenomena. Near the boundary regions of stability, both amplitude and cycle of deformation are greatly affected by the amplitude of disturbances. The dynamic instability is governed by the inverse symmetry primary mode with minimum characteristic frequency which is specific for the circular arch. The dynamic stability has high parameter dependency, and the instability regions have a complicated shapes. Although flattened arch has a smaller static critical load, it provides the dynamic stability against the disturbance. 5 refs., 10 figs.

  7. Markedly hypoplastic circumflex retroesophageal right aortic arch: MR imaging and surgical implications

    International Nuclear Information System (INIS)

    Circumflex retroesophageal right aortic arch with a markedly hypoplastic retroesophageal segment is a rare anomaly of the aortic arch. Adequate surgical management relies on precise diagnosis, which might not be feasible with echocardiography. To demonstrate the utility of MR imaging in establishing the diagnosis and to describe potential pitfalls in making the diagnosis. Three patients with a circumflex retroesophageal right aortic arch with a markedly hypoplastic retroesophageal segment were retrospectively evaluated. All patients underwent evaluation by echocardiography and MR imaging. The MR imaging consisted of 3-D MR angiography in two patients and fast gradient recalled echo with cardiac-triggered segmented acquisition in one patient. Surgical confirmation was obtained on all three patients. The arch anatomy was accurately depicted in all three patients by MR imaging and in none of the patients by echocardiography. MR imaging is extremely useful in establishing the diagnosis of markedly hypoplastic retroesophageal circumflex right aortic arch and thus helps in surgical planning. (orig.)

  8. A shared role for sonic hedgehog signalling in patterning chondrichthyan gill arch appendages and tetrapod limbs.

    Science.gov (United States)

    Gillis, J Andrew; Hall, Brian K

    2016-04-15

    Chondrichthyans (sharks, skates, rays and holocephalans) possess paired appendages that project laterally from their gill arches, known as branchial rays. This led Carl Gegenbaur to propose that paired fins (and hence tetrapod limbs) originally evolved via transformation of gill arches. Tetrapod limbs are patterned by asonic hedgehog(Shh)-expressing signalling centre known as the zone of polarising activity, which establishes the anteroposterior axis of the limb bud and maintains proliferative expansion of limb endoskeletal progenitors. Here, we use loss-of-function, label-retention and fate-mapping approaches in the little skate to demonstrate that Shh secretion from a signalling centre in the developing gill arches establishes gill arch anteroposterior polarity and maintains the proliferative expansion of branchial ray endoskeletal progenitor cells. These findings highlight striking parallels in the axial patterning mechanisms employed by chondrichthyan branchial rays and paired fins/limbs, and provide mechanistic insight into the anatomical foundation of Gegenbaur's gill arch hypothesis. PMID:27095494

  9. Preliminary research on cycloid as a line type of the arch dam

    Institute of Scientific and Technical Information of China (English)

    DU Tingna; YE Rongbo; ZHAO Haifeng

    2012-01-01

    Currently, there are a wide range of line types in the field of arch dam designing and construction, and each of them may have their own strength and weakness disparately. A trade-off between the size, stress, as well as the construction cost and complex- ity of the dam needs to be made in order to arrive at a new solution called the cycloid arch dam. Through redevelopment of VBA us- ing AutoCAD, the arch ring and the center of the arch line have been designed. Also, the stress analysis on parabola and cycloid have been done, which provides a theoretical principle that the cycloid could be regarded as a new line type of the arch dam.

  10. Automatic dental arch detection and panoramic image synthesis from CT images.

    Science.gov (United States)

    Sa-Ing, Vera; Wangkaoom, Kongyot; Thongvigitmanee, Saowapak S

    2013-01-01

    Due to accurate 3D information, computed tomography (CT), especially cone-beam CT or dental CT, has been widely used for diagnosis and treatment planning in dentistry. Axial images acquired from both medical and dental CT scanners can generate synthetic panoramic images similar to typical 2D panoramic radiographs. However, the conventional way to reconstruct the simulated panoramic images is to manually draw the dental arch on axial images. In this paper, we propose a new fast algorithm for automatic detection of the dental arch. Once the dental arch is computed, a series of synthetic panoramic images as well as a ray-sum panoramic image can be automatically generated. We have tested the proposed algorithm on 120 CT axial images and all of them can provide the decent estimate of the dental arch. The results show that our proposed algorithm can mostly detect the correct dental arch.

  11. Abnormal aortic arch morphology in Turner syndrome patients is a risk factor for hypertension.

    Science.gov (United States)

    De Groote, Katya; Devos, Daniël; Van Herck, Koen; Demulier, Laurent; Buysse, Wesley; De Schepper, Jean; De Wolf, Daniël

    2015-09-01

    Hypertension in Turner syndrome (TS) is a multifactorial, highly prevalent and significant problem that warrants timely diagnosis and rigorous treatment. The objective of this study was to investigate the association between abnormal aortic arch morphology and hypertension in adult TS patients. This was a single centre retrospective study in 74 adult TS patients (age 29.41 ± 8.91 years) who underwent a routine cardiac MRI. Patients were assigned to the hypertensive group (N = 31) if blood pressure exceeded 140/90 mmHg and/or if they were treated with antihypertensive medication. Aortic arch morphology was evaluated on MRI images and initially assigned as normal (N = 54) or abnormal (N = 20), based on the curve of the transverse arch and the distance between the left common carotid-left subclavian artery. We additionally used a new more objective method to describe aortic arch abnormality in TS by determination of the relative position of the highest point of the transverse arch (AoHP). Logistic regression analysis showed that hypertension is significantly and independently associated with age, BMI and abnormal arch morphology, with a larger effect size for the new AoHP method than for the classical method. TS patients with hypertension and abnormal arch morphology more often had dilatation of the ascending aorta. There is a significant association between abnormal arch morphology and hypertension in TS patients, independent of age and BMI, and not related to other structural heart disease. We suggest that aortic arch morphology should be included in the risk stratification for hypertension in TS and propose a new quantitative method to express aortic arch morphology.

  12. Abnormal aortic arch morphology in Turner syndrome patients is a risk factor for hypertension.

    Science.gov (United States)

    De Groote, Katya; Devos, Daniël; Van Herck, Koen; Demulier, Laurent; Buysse, Wesley; De Schepper, Jean; De Wolf, Daniël

    2015-09-01

    Hypertension in Turner syndrome (TS) is a multifactorial, highly prevalent and significant problem that warrants timely diagnosis and rigorous treatment. The objective of this study was to investigate the association between abnormal aortic arch morphology and hypertension in adult TS patients. This was a single centre retrospective study in 74 adult TS patients (age 29.41 ± 8.91 years) who underwent a routine cardiac MRI. Patients were assigned to the hypertensive group (N = 31) if blood pressure exceeded 140/90 mmHg and/or if they were treated with antihypertensive medication. Aortic arch morphology was evaluated on MRI images and initially assigned as normal (N = 54) or abnormal (N = 20), based on the curve of the transverse arch and the distance between the left common carotid-left subclavian artery. We additionally used a new more objective method to describe aortic arch abnormality in TS by determination of the relative position of the highest point of the transverse arch (AoHP). Logistic regression analysis showed that hypertension is significantly and independently associated with age, BMI and abnormal arch morphology, with a larger effect size for the new AoHP method than for the classical method. TS patients with hypertension and abnormal arch morphology more often had dilatation of the ascending aorta. There is a significant association between abnormal arch morphology and hypertension in TS patients, independent of age and BMI, and not related to other structural heart disease. We suggest that aortic arch morphology should be included in the risk stratification for hypertension in TS and propose a new quantitative method to express aortic arch morphology. PMID:24935217

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

    Full Text Available InP.Emb.20.AllAg.Maxillary_arch_junction mm9 Input control Embryo Maxillary arch jun...ction http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Emb.20.AllAg.Maxillary_arch_junction.bed ...

  1. Frontal plane multi-segment foot kinematics in high- and low-arched females during dynamic loading tasks.

    Science.gov (United States)

    Powell, Douglas W; Long, Benjamin; Milner, Clare E; Zhang, Songning

    2011-02-01

    The functions of the medial longitudinal arch have been the focus of much research in recent years. Several studies have shown kinematic differences between high- and low-arched runners. No literature currently compares the inter-segmental foot motion of high- and low-arched recreational athletes. The purpose of this study was to examine inter-segmental foot motion in the frontal plane during dynamic loading activities in high- and low-arched female athletes. Inter-segmental foot motions were examined in 10 high- and 10 low-arched female recreational athletes. Subjects performed five barefooted trials in each of the following randomized movements: walking, running, downward stepping and landing. Three-dimensional kinematic data were recorded. High-arched athletes had smaller peak ankle eversion angles in walking, running and downward stepping than low-arched athletes. At the rear-midfoot joint high-arched athletes reached peak eversion later in walking and downward stepping than the low-arched athletes. The high-arched athletes had smaller peak mid-forefoot eversion angles in walking, running and downward stepping than the low-arched athletes. The current findings show that differences in foot kinematics between the high- and low-arched athletes were in position and not range of motion within the foot.

  2. Quantum Bidding in Bridge

    Science.gov (United States)

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

    2014-04-01

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

  3. Bridge of Light

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Lying gleaming white under a brooding sky,the Lhasa River Railway Bridge forms a gate to Lhasa City.Built as a part of Qinghai-Tibet Railway,on July 1,2011, the highest altitude railway in the world has been in service for five years. Lhasa,Tibet

  4. 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...

  5. Building Bridges to China.

    Science.gov (United States)

    Wasta, Stephanie; Scott, Margaret

    1998-01-01

    Describes a theme cycle called "Building Bridges to China" developed for third grade students that focuses on the similarities between the lives of children and families in China and the United States. Explains that the theme cycle addresses the National Geography Standards and three of the National Council for the Social Studies standards. (CMK)

  6. Measuring medial longitudinal arch deformation during gait. A reliability study

    DEFF Research Database (Denmark)

    Bencke, Jesper; Christiansen, Ditte; Jensen, Anne Kathrine Bendrup;

    2012-01-01

    Clinical evaluation of medial longitudinal arch deformation (MLAD) during walking gait is often estimated from static measures of e.g. navicular drop (ND) measured during quiet standing. The aim of the present study was to test the reliability of a new three-dimensional method of measuring the MLAD...... during gait and to compare this method with a static measure and a 2D dynamic method. Fifty-two feet (26 healthy male participants) were tested twice 4-9 days apart in a biomechanical gait analysis laboratory using a 3D three-marker foot model, a 2D video-based model for the measurement of MLAD during...... and showed that ND obtained during quiet standing could not predict the MLAD during gait. The 3D method, or alternatively the 2D method, may be used in clinical settings as reliable methods for easy estimation of the foot longitudinal stability....

  7. The Evolution of Protoplanetary Discs in the Arches Cluster

    CERN Document Server

    Olczak, C; Harfst, S; Pfalzner, S; Zwart, S Portegies

    2012-01-01

    Most stars form in a cluster environment. These stars are initially surrounded by discs from which potentially planetary systems form. Of all cluster environments starburst clusters are probably the most hostile for planetary systems in our Galaxy. The intense stellar radiation and extreme density favour rapid destruction of circumstellar discs via photoevaporation and stellar encounters. Evolving a virialized model of the Arches cluster in the Galactic tidal field we investigate the effect of stellar encounters on circumstellar discs in a prototypical starburst cluster. Despite its proximity to the deep gravitational potential of the Galactic centre only a moderate fraction of members escapes to form an extended pair of tidal tails. Our simulations show that encounters destroy one third of the circumstellar discs in the cluster core within the first 2.5 Myr of evolution, preferentially affecting the least and most massive stars. A small fraction of these events causes rapid ejection and the formation of a we...

  8. Variation in the Branching Pattern of the Superficial Palmar Arch

    Directory of Open Access Journals (Sweden)

    Sumalatha S

    2016-05-01

    Full Text Available In this article we describe a rare variation in the superficial palmar arch (SPA encountered during routine cadaveric dissection. SPA was formed by the superficial branches of ulnar and radial arteries which provided a proper digital branch to the ulnar side of the little finger and three common palmar digital branches to the medial four digits. Additionally a first common digital artery was seen to emerge from the radial side of SPA which further divided into the arteria princeps pollicis and arteria radialis indicis. We also found a small communicating branch between the arteria princeps pollicis and the radial artery in the anatomical snuff box. Such arterial variations in the palm due to alteration in the developmental sequence remains a crucial issue in the reconstructive hand surgeries, especially while dealing with the innovative microsurgical procedures, where these varied patterns act as pivotal points around which successful results of various advanced surgical procedures revolve.

  9. Bacteroides fragilis aortic arch pseudoaneurysm: case report with review

    Directory of Open Access Journals (Sweden)

    Yang Yu-Jen

    2008-05-01

    Full Text Available Abstract We present a case of 58-year-old woman with underlying diabetes mellitus, hepatitis C virus-related liver cirrhosis, and total hysterectomy for uterine myoma 11 moths ago, who was diagnosed ruptured aortic arch mycotic pseudoaneurysm after a certain period of survey for her unknown fever cause. After emergent surgery with prosthetic graft interposition, all her blood cultures and tissue cultures revealed pathogen with Bacteroides fragilis. Although mycotic aneurysms have been well described in literatures, an aneurysm infected solely with Bacteroides fragilis is unusual, with only eight similar cases in the literature. Here we reported the only female case with her specific clinical and management course and summarized all reported cases of mycotic aneurysm caused by Bacteroides fragilis to clarify their conditions and treatments, alert the difficulty in diagnosis, and importance of highly suspicious.

  10. Parallel computation of seismic analysis of high arch dam

    Institute of Scientific and Technical Information of China (English)

    Chen Houqun; Ma Huaifa; Tu Jin; Cheng Guangqing; Tang Juzhen

    2008-01-01

    Parallel computation programs are developed for three-dimensional meso-mechanics analysis of fully-graded dam concrete and seismic response analysis of high arch dams (ADs), based on the Parallel Finite Element Program Generator (PFEPG). The computational algorithms of the numerical simulation of the meso-structure of concrete specimens were studied. Taking into account damage evolution, static preload, strain rate effect, and the heterogeneity of the meso-structure of dam concrete, the fracture processes of damage evolution and configuration of the cracks can be directly simulated. In the seismic response analysis of ADs, all the following factors are involved, such as the nonlinear contact due to the opening and slipping of the contraction joints, energy dispersion of the far-field foundation, dynamic interactions of the dam-foundation-reservoir system, and the combining effects of seismic action with all static loads. The correctness, reliability and efficiency of the two parallel computational programs are verified with practical illustrations.

  11. The randomized shortened dental arch study: tooth loss.

    Science.gov (United States)

    Walter, M H; Weber, A; Marré, B; Gitt, I; Gerss, J; Hannak, W; Hartmann, S; Heydecke, G; Huppertz, J; Jahn, F; Ludwig, A; Mundt, T; Kern, M; Klein, V; Pospiech, P; Stumbaum, M; Wolfart, S; Wöstmann, B; Busche, E; Böning, K; Luthardt, R G

    2010-08-01

    The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA concept. First tooth loss after treatment was the primary outcome measure. This event occurred in 13 patients in the RDP group and nine patients in the SDA group. The respective Kaplan-Meier survival rates at 38 months were 0.83 (95% CI: 0.74-0.91) in the RDP group and 0.86 (95% CI: 0.78-0.95) in the SDA group, the difference being non-significant. PMID:20400723

  12. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

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

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

  13. 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. 

  14. Outcomes of single-stage total arch replacement via clamshell incision

    Directory of Open Access Journals (Sweden)

    Ishizaka Toru

    2011-09-01

    Full Text Available Abstract Background Treatment of complex aortic pathologies involving the transverse arch with extensive involvement of the descending aorta remains a surgical challenge. Since clamshell incision provides superior exposure of the entire thoracic aorta, we evaluated the use of this technique for single-stage total arch replacement by arch vessel reconstruction. Methods The arch-first technique combined with clamshell incision was used in 38 cases of aneurysm and aortic disease in 2008 and 2009. Extensive total arch replacement was used with clamshell incision for reconstruction of arch vessels under deep hypothermic circulatory arrest. Results Overall 30-day mortality was 13%. The mean operating time was approximately 8 hours. Deep hypothermia resulted in mean CPB time exceeding 4.5 hours and mean duration of circulatory arrest was 25 minutes. The overall postoperative temporary and permanent neurologic dysfunction rates were 3% and 3% for elective and 3% and 0% for emergency surgery, respectively. All patients except the five who died in hospital were discharged without nursing care after an average post-operative hospital stay of 35 days. Conclusions The arch-first technique, combined with clamshell incision, provides expeditious replacement of the thoracic aorta with an acceptable duration of hypothermic circulatory arrest and minimizes the risk of retrograde atheroembolism by using antegrade perfusion.

  15. [Effects of removable partial dentures on the quality of life in people with shortened dental arches].

    Science.gov (United States)

    Armellini, D B; Heydecke, G; Witter, D J; Creugers, N H J

    2009-12-01

    In order to assess the enhanced value of removable partial dentures on the quality of life, patients at 2 university clinics were screened for the presence of complete or shortened dental arches. Those selected were assigned to 1 of 5 subgroups: 1) a shortened dental arch with all frontal teeth, 2) a shortened dental arch with one or more frontal diastemas, 3) a shortened dental arch with all frontal teeth, restored by a removable partial denture, 4) a shortened dental arch and several diastemas, restored by a removable partial denture, 5) a complete dental arch. The participants completed the Oral Health Impact Profile (OHIP-49) and the Short Form Health Survey (SF-36). Clinical data recorded were: whether any teeth were missing and if so which, whether or not these had been replaced by a removable partial denture, and the number of occluding pairs of (pre)molars. The results revealed that a shortenend dental arch has a certain impact on the quality of life. However, the participants only experienced benefits from a removable partial denture if the denture also replaced frontal teeth. PMID:20101937

  16. Effect of antipronation foot orthosis geometry on compression of heel and arch soft tissues

    Directory of Open Access Journals (Sweden)

    Declan Sweeney, BSc (Hon

    2016-09-01

    Full Text Available This study aimed to understand how systematic changes in arch height and two designs of heel wedging affect soft tissues under the foot. Soft tissue thickness under the heel and navicular was measured using ultrasound. Heel pad thickness was measured while subjects were standing on a flat surface and also while they were standing on an orthosis with 4 and 8 degree extrinsic wedges and 4 and 8 mm intrinsic wedges (n = 27. Arch soft tissue thickness was measured when subjects were standing and when standing on an orthosis with –6 mm, standard, and +6 mm increments in arch height (n = 25. Extrinsic and intrinsic heel wedges significantly increased soft tissue thickness under the heel compared with no orthosis. The 4 and 8 degree extrinsic wedges increased tissue thickness by 28.3% and 27.6%, respectively, while the 4 and 8 mm intrinsic wedges increased thickness by 23.0% and 14.6%, respectively. Orthotic arch height significantly affected arch soft tissue thickness. Compared with the no orthosis condition, the –6 mm, standard, and +6 mm arch heights decreased arch tissue thickness by 9.1%, 10.2%, and 11.8%, respectively. This study demonstrates that change in orthotic geometry creates different plantar soft tissue responses that we expect to affect transmission of force to underlying foot bones.

  17. O' Connell bridge inspection by means of Ground Penetrating Radar

    Science.gov (United States)

    Santos Assuncao, Sonia, ,, Dr

    2016-04-01

    Ground Penetrating Radar (GPR) is a well-known technique successfully applied in different areas. In structural inspection the methodology may expose information about structural arrangement and pathologies. GPR emits high frequency electromagnetic impulses allowing to detect changes on the electromagnetic properties: electrical conductivity, dielectric constant and magnetic permeability. The central frequency of the each antenna is characterized by a specific resolution and penetration depth. Therefore, different scales of structures can be analysed. High frequency antennas output high resolution images/signals about the shallowest elements such as rebar and the thickness of the first layer. On the other hand, intermediate or lower frequency antennas locate deeper structures, such as the thickness of the arch. The compilation of distinct frequencies gives a better understanding and a more accurate detection of elements in the inner structure. O'Connell Bridge (1877) is one of 24 bridges along River Liffey and one the most famous historical structures in Dublin. It is composed by sandstones and granite and covered by asphalt which represents a suitable structure to evaluate by means of GPR. The lack of inner structural information, especially the thickness of the layer, presence of reinforcement or other metallic elements of support required, at least, a dual frequency analysis of the bridge. In this case, it was applied the (200 MHz and 600 MHz) Multi-Channel Stream EM combined with 1.6 GHz GSSI high frequency antenna. The inspection of bridges by means of GPR may provide not exclusively interesting structural data but historical information and the state of conservation.

  18. Research on Selections of Bridge Site and Type of Hutiaoxia Jinsha River Bridge%虎跳峡金沙江大桥方案研究

    Institute of Scientific and Technical Information of China (English)

    刘伟; 陈克坚; 游励晖

    2013-01-01

    Research purposes:The Hutiaoxia Jinsha River Bridge is the key project of Lijiang-Xianggelila Railway and is located in the sensitive environmental and high seismic intensity region with the active fault.The reasonable bridge site and type should be selected for this bridge on consideration of the railway alignment,environment protection,topography,geological condition and the plan of hydraulic engineering on the midstream of the river.Research conclusions:(1)Using the deck type steel braced arch at the No.8 bridge site(416m) of the Hutaioxia Jinsha River Bridge is the best engineering plan.Using the steel truss suspension bridge at No.27 bridge site (98 + 660 +98 m) can remain the condition for the hydroelectric plan of river and can get the better economic and social benefits.(2) The deck type steel braced arch has features of the good load bearing capacity,good rigidity and nice looking and is suitable for the high mountain and deep valley area,but it produces the impact on the water storage and shipping under bridge because the arch rib is installed on bottom of the structure.(3) The steel truss suspension bridge has the features of the fine anti-seismic performance and good rigidity to meet the train requirement.(4) The research result can provide the reference to the type selection of the large span railway bridge in mountain and deep valley area.%研究目的:虎跳峡金沙江大桥为丽香铁路的重点控制性工程.大桥桥址位于环境敏感区、高烈度地震区及断裂发育带,需要综合线路走线、环保、地形、地质情况及金沙江中游水电开发规划的影响,选择虎跳峡金沙江大桥的合理桥位及桥式方案.研究结论:(1)虎跳峡金沙江大桥的8号桥位416 m上承式钢桁拱桥是最优的工程方案,27号桥位(98+660 +98)m钢桁梁悬索桥可以为规划中的水电开发预留条件,整体上经济、社会效应更好;(2)上承式钢桁拱桥承载能力高、刚度大、造型优美,适用于

  19. The Role of Arch Compression and Metatarsophalangeal Joint Dynamics in Modulating Plantar Fascia Strain in Running.

    Directory of Open Access Journals (Sweden)

    Kirsty A McDonald

    Full Text Available Elastic energy returned from passive-elastic structures of the lower limb is fundamental in lowering the mechanical demand on muscles during running. The purpose of this study was to investigate the two length-modulating mechanisms of the plantar fascia, namely medial longitudinal arch compression and metatarsophalangeal joint (MPJ excursion, and to determine how these mechanisms modulate strain, and thus elastic energy storage/return of the plantar fascia during running. Eighteen runners (9 forefoot and 9 rearfoot strike performed three treadmill running trials; unrestricted shod, shod with restricted arch compression (via an orthotic-style insert, and barefoot. Three-dimensional motion capture and ground reaction force data were used to calculate lower limb kinematics and kinetics including MPJ angles, moments, powers and work. Estimates of plantar fascia strain due to arch compression and MPJ excursion were derived using a geometric model of the arch and a subject-specific musculoskeletal model of the plantar fascia, respectively. The plantar fascia exhibited a typical elastic stretch-shortening cycle with the majority of strain generated via arch compression. This strategy was similar in fore- and rear-foot strike runners. Restricting arch compression, and hence the elastic-spring function of the arch, was not compensated for by an increase in MPJ-derived strain. In the second half of stance the plantar fascia was found to transfer energy between the MPJ (energy absorption and the arch (energy production during recoil. This previously unreported energy transfer mechanism reduces the strain required by the plantar fascia in generating useful positive mechanical work at the arch during running.

  20. The Role of Arch Compression and Metatarsophalangeal Joint Dynamics in Modulating Plantar Fascia Strain in Running.

    Science.gov (United States)

    McDonald, Kirsty A; Stearne, Sarah M; Alderson, Jacqueline A; North, Ian; Pires, Neville J; Rubenson, Jonas

    2016-01-01

    Elastic energy returned from passive-elastic structures of the lower limb is fundamental in lowering the mechanical demand on muscles during running. The purpose of this study was to investigate the two length-modulating mechanisms of the plantar fascia, namely medial longitudinal arch compression and metatarsophalangeal joint (MPJ) excursion, and to determine how these mechanisms modulate strain, and thus elastic energy storage/return of the plantar fascia during running. Eighteen runners (9 forefoot and 9 rearfoot strike) performed three treadmill running trials; unrestricted shod, shod with restricted arch compression (via an orthotic-style insert), and barefoot. Three-dimensional motion capture and ground reaction force data were used to calculate lower limb kinematics and kinetics including MPJ angles, moments, powers and work. Estimates of plantar fascia strain due to arch compression and MPJ excursion were derived using a geometric model of the arch and a subject-specific musculoskeletal model of the plantar fascia, respectively. The plantar fascia exhibited a typical elastic stretch-shortening cycle with the majority of strain generated via arch compression. This strategy was similar in fore- and rear-foot strike runners. Restricting arch compression, and hence the elastic-spring function of the arch, was not compensated for by an increase in MPJ-derived strain. In the second half of stance the plantar fascia was found to transfer energy between the MPJ (energy absorption) and the arch (energy production during recoil). This previously unreported energy transfer mechanism reduces the strain required by the plantar fascia in generating useful positive mechanical work at the arch during running.

  1. Correlation between arch form and facial form: A cross sectional study

    OpenAIRE

    Sanjna Nayar; Aruna; Santhosh MR; Wasim Manzoor

    2015-01-01

    Arch form is a key determinant in teeth position. Teeth selection and placement must be based on the functional and esthetic needs of the patient. Keeping in mind, the biomechanics involved with the prosthesis. The aim of the study was to evaluate the correlation between arch form and facial form. About 40 individuals in the age group of 20-25 years were involved in the study. The arch form and facial form were analyzed statistically to check for any correlation. It was found that, 63.63% of ...

  2. Changes in lower dental arch dimensions and tooth alignment in young adults without orthodontic treatment

    OpenAIRE

    Bruno Aldo Mauad; Robson Costa Silva; Mônica Lídia Santos de Castro Aragón; Luana Farias Pontes; Newton Guerreiro da Silva Júnior; David Normando

    2015-01-01

    OBJECTIVE: The aim of this longitudinal study, comprising young adults without orthodontic treatment, was to assess spontaneous changes in lower dental arch alignment and dimensions. METHODS: Twenty pairs of dental casts of the lower arch, obtained at different time intervals, were compared. Dental casts obtained at T1 (mean age = 20.25) and T2 (mean age = 31.2) were compared by means of paired t-test (p < 0.05). RESULTS: There was significant reduction in arch dimensions: 0.43 mm for interca...

  3. Influence of Process Parameters on Forming of Arched Aircraft Skin with Aluminum Alloy 2024

    Science.gov (United States)

    Yan, Huajun; Zhang, Shuangjie; Gao, Ying

    To solve these problems such as easily springback and hardly controlling the loading direction when arched aircraft skin is formed, stretch forming of steel plate with aluminium alloy 2024 was simulated by the finite element software Abaqus, and the shape of the stretch forming die was the arc with radius 350mm. The influence of process parameters, such as stretch forming track and dangling length on forming of arched aircraft skin was researched, and the reasonable range of stretch forming length track and dangling length was given. The results have significance for research the forming law of arched aircraft skin.

  4. Seismic response analysis of arch dam-water-rock foundation systems

    Institute of Scientific and Technical Information of China (English)

    杜修力; 王进廷

    2004-01-01

    The effect of water compressibility on the seismic responses of arch dams is not well understood. In this paper, a numerical model is developed with rigorous representation of the dynamic interaction between arch dam-waterrock foundation. The model is applied to the seismic response analysis of an arch dam with a height of 292m designed to a seismic intensity of Ⅸ. It is shown that consideration of the water compressibility clearly decreases the stress responses at key positions of the dam, while the added mass model gives a conservative estimate.

  5. CORRELATION BETWEEN DURATION OF BOTTLE-FEEDING AND DENTAL ARCH MEASUREMENT IN DECIDUOUS DENTITION

    OpenAIRE

    Meldo Mahniza; Retno Hayati; Sri Harini

    2015-01-01

    The purpose of this study was to observe the correlation between duration of bottle feeding and dental arch measurement in deciduous dentition. Duration of bottle feeding was divided into 4 groups: ≤ 24 months, 25 – 36 months, 37 – 48 months, and > 48 months. The subjects were 120 kindergarten pupils, aged 3 – 5 years old. Measurements was done on the models of maxilla and mandible with digital caliper for the width and length of dental arch and using flexible curve for dental arch circumf...

  6. [Retention of adhesive bridges].

    Science.gov (United States)

    Raes, F; De Boever, J

    1994-04-01

    Since the development of adhesive bridges in the early seventies, the retention and therefore the durability of these bridges has been tremendously improved. Conditioning of the non-precious metal by silanisation, careful acid etching of the enamel and the use of the appropriate composite resin are of prime importance. Furthermore, the meticulous preparation with enough interproximal embrace, occlusal rests, interocclusal clearance and cingulum stops is equally important. Including more teeth in the design does not necessarily lead to an improved retention. Besides the material and technical aspects, the whole clinical procedure needs much attention. The retention does not depend on one single factor, but on the precision of all the necessary clinical steps and on a well-defined selection of the material. In this way a five-year survival rate of close to 80% can be obtained. PMID:11830965

  7. BRIDGING SERVICE QUALITY GAPS

    OpenAIRE

    BARKATH UNISSA

    2012-01-01

    Bridging the Service quality gaps is one of the foremost areas of concern for amarketer. Service marketing is inherently different from product or goods marketing.Services are distinctively characterized by their intangible, heterogeneous, inseparableand perishable nature. The importance of the service sector in today's world is a verywidely accepted and renowned idea. “We are already experiencing a service society“services do have some basic characteristics which make them fundamentally diff...

  8. Bridging as Coercive Accommodation

    CERN Document Server

    Bos, J W; Mineur, A M; Bos, Johan; Buitelaar, Paul; Mineur, Anne-Marie

    1995-01-01

    In this paper we discuss the notion of "bridging" in Discourse Representation Theory as a tool to account for discourse referents that have only been established implicitly, through the lexical semantics of other referents. In doing so, we use ideas from Generative Lexicon theory, to introduce antecedents for anaphoric expressions that cannot be "linked" to a proper antecedent, but that do not need to be "accommodated" because they have some connection to the network of discourse referents that is already established.

  9. Nematic liquid crystal bridges

    Science.gov (United States)

    Doss, Susannah; Ellis, Perry; Vallamkondu, Jayalakshmi; Danemiller, Edward; Vernon, Mark; Fernandez-Nieves, Alberto

    We study the effects of confining a nematic liquid crystal between two parallel glass plates with homeotropic boundary conditions for the director at all bounding surfaces. We find that the free surface of the nematic bridge is a surface of constant mean curvature. In addition, by changing the distance between the plates and the contact angle with the glass plates, we transition between loops and hedgehogs that can be either radial or hyperbolic.

  10. Dental arch changes associated with rapid maxillary expansion: A retrospective model analysis study

    Directory of Open Access Journals (Sweden)

    Ivor M D′Souza

    2015-01-01

    Full Text Available Introduction: Transverse deficiency of the maxilla is a common clinical problem in orthodontics and dentofacial orthopedics. Transverse maxillary deficiency, isolated or associated with other dentofacial deformities, results in esthetic and functional impairment giving rise to several clinical manifestations such as asymmetrical facial growth, positional and functional mandibular deviations, altered dentofacial esthetics, adverse periodontal responses, unstable dental tipping, and other functional problems. Orthopedic maxillary expansion is the preferred treatment approach to increase the maxillary transverse dimension in young patients by splitting of the mid palatal suture. This orthopedic procedure has lately been subject of renewed interest in orthodontic treatment mechanics because of its potential for increasing arch perimeter to alleviate crowding in the maxillary arch without adversely affecting facial profile. Hence, the present investigation was conducted to establish a correlation between transverse expansion and changes in the arch perimeter, arch width and arch length. Methods: For this purpose, 10 subjects (five males, five females were selected who had been treated by rapid maxillary expansion (RME using hyrax rapid palatal expander followed by fixed mechanotherapy (PEA. Pretreatment (T1, postexpansion (T2, and posttreatment (T3 dental models were compared for dental changes brought about by RME treatment and its stability at the end of fixed mechanotherapy. After model measurements were made, the changes between T1-T2, T2-T3 and T1-T3 were determined for each patient. The mean difference between T1-T2, T2-T3 and T1-T3 were compared to assess the effects of RME on dental arch measurements. Results are expressed as mean ± standard deviation and are compared by repeated measures analysis of variance followed by a post-hoc test. Arch perimeter changes are correlated with changes in arch widths at the canine, premolar and molar

  11. Environmental life cycle assessment comparison between two bridge types: reinforced concrete bridge and steel composite bridge

    DEFF Research Database (Denmark)

    Du, Guangli; Karoumi, Raid

    2013-01-01

    not been integrated into the decision-making process. This paper presents a systematic LCA method for quantifying the environmental impacts for bridges. The comparison study is performed between a reinforced concrete bridge and a steel bridge as an alternative design, with several key maintenance and EOL......The concept of sustainable construction has attracted an increased attention. Bridge infrastructures and their belonged construction activities consume considerable material and energy, which is responsible for large environmental burdens. However, the environmental assessment of bridges has...

  12. A Review of Diseases of Aortic Arch: Diagnosis by CTA

    Directory of Open Access Journals (Sweden)

    S. Sabouri

    2007-05-01

    Full Text Available The noninvasive revolution in cardiovascular imaging has altered the diagnostic algorithm for all types of acquired and congenital cardiovascular disease. CT techniques are commonly used in the diagnosis of aortic arch and its major branch vessels as well as thoracic and abdominal aortic diseases. CT angiogra-phy combines with CT scans obtained detailed in-formation on precise morphology and extent of dis-ease. Studies were performed on an MDCT unit (4row GE light speed. In infants and small children, the seda-tion rate for CT was lower than that used for patients of similar age undergoing cardiac MR imaging. Seda-tion times ranged between 5 and 10 min, in the pedi-atric population, MDCT was performed with a 1- to 2.5-mm slice thickness in adults, MDCT was per-formed with a 2.5-mm slice thickness with 50% re-construction overlap, pitch 0.75-1.CT angiographic studies were performed with nonionic contrast mate-rial with iodine concentrations of 300 mg/mL admin-istered at a dose of 2-3 mL/kg. Contrast material was injected by power injection, followed by normal sa-line, an automated bolus-tracking technique was used at an injection rate of 2-4 mL/sec. the bolus-tracking device was placed on the ascending aorta. For pa-tients with thoracic outlet syndrome, CT angiogram was performed with neutral position of arm and ab-duction of the arm. Radiologist studied the CT image data in an axial cine paging mode as well as multiplanar reformations. To plan effective management of Aorta disease, CTA is displayed using a combination of 3D images, such as those obtained by multiplanar reformation (MPR, curved planar reformation (CPR, maximum intensity projection (MIP and volume rendering (VR. Case reports include coarctation of aorta, vascular ring, right sided aorta, interrupted aortic arch, abber-ant vessels, paitent ductus arteriosus, subclavian steel syndrome, aneurysm, dissection, thoracic outlet syn-drome, arthritis and atherosclerotic stenosis.

  13. 南广铁路西江桥位、桥式方案的选择%Selection of the Site and Type of Xijiang River Bridge on Nanning-Guangzhou Railway

    Institute of Scientific and Technical Information of China (English)

    陈达建

    2011-01-01

    为了使南广铁路以较经济合理的桥位、桥式跨越西江,并满足国家内河Ⅱ级通航等级要求,对适合设桥的小湘河段和三榕峡河段两桥位根据水文地质、通航条件、桥墩防撞设置、施工难易程度等方面进行比选.小湘河段桥位设计桥式为1跨450 m钢箱拱桥,三榕峡河段桥位设计桥式为连续钢桁粱斜拉桥.比较结论为:南广铁路宜在肇庆市内小湘河段跨越西江,设计为1跨过江的450 m钢箱提篮拱桥,提篮拱采用缆索吊机分段吊装.%In order to find out economic and rational bridge site and type for Nanning-Guangzhou Railway to traverse Xijiang river and to satisfy the II class nevigation requirements of domestic rivers, comparative selection has been carried out between two suitable bridge sites; Xiaoxiang river section and Sanrongxia river section, in terms of hydrogeology, nevigation condition, impact-protection installation of piers, construction feasibility, etc. Bridge type of Xiaoxiang site will be a simple span 450 m steel box arch bridge, bridge type of Sanrongxia site will be continuous steel truss cable stayed bridge. It has been concluded that, Naning-Guangzhou railway is recommended to traverse Xijiang river at Xiaoxiang river section in Zhaoqin city, the designed bridge will be a 450 m steel box basket arch bridge, the basket arch will be erected by cable crane by sections.

  14. The Comparison of Different Degree of Convexity and 3D Modeling of Involute Hyperbolic Arch Dam

    Institute of Scientific and Technical Information of China (English)

    DU Qi-lu; DU Ting-na; ZHAO Hai-feng

    2011-01-01

    Because of good quality of compressive resistance, the hyperbolic arch dam is being increasingly applied to engineering projects. In order to satisfy the needs of compressive resistance under the conditions of high water pressure, a stress analysis is required for the dam. During the stress analysis process however, due to the complexity of the three-dimensional modeling, it is very hard to form a model. Therefore, the stress analysis process is a barrier for the arch dam. In this article, based on the research of the new line-type arch dam, a mathematical model in different degree of convexity conditions of the dam is established; using the C + + language program, a computer three-dimensional model simulation is realized on AutoCAD. The accurate three-dimensional model is providing a finite element optimization design of the involute hyperbolic arch dam for the next step.

  15. RCC Arch Dam Structure on the Taxi River and Water Storage Measure During Construction

    Institute of Scientific and Technical Information of China (English)

    刘光廷; 李鹏辉; 胡昱; 张富德; 谢树南

    2002-01-01

    The new structure of roller compacted concrete (RCC) arch dams is presented for extremely cold and earthquake prone areas. The influence of construction plans and improved materials on the stresses in the Taxi River dam is also given. Earlier impoundment of water is shown to not only benefit the engineering design but also improve the stresses during construction in winter. Low cement content in the concrete and artificial short joints improved the monolithic structure and the transmitted forces. The concrete plug installed in the first cooled part of the arch dam provides excellent force transmission in the arch, which increases the monolith of the earlier arch, reduces the increasing thermal stresses that occur later, and improves the deformation flexibility of the dam.

  16. Right aortic arch with aberrant left innominate artery arising from Kommerell's diverticulum*

    Science.gov (United States)

    Faistauer, Ângela; Torres, Felipe Soares; Faccin, Carlo Sasso

    2016-01-01

    We report a case of an uncommon thoracic aorta anomaly-right aortic arch with aberrant left innominate artery arising from Kommerell's diverticulum-that went undiagnosed until adulthood. PMID:27777481

  17. Numerical Analysis on Protecting Performance of Layered Arch Structures Subjected to Blast Loading

    Directory of Open Access Journals (Sweden)

    Dong Yongxiang

    2009-03-01

    Full Text Available Dynamic responses of layered arch structure composed of different materials subjected to blast loading are analysed by numerical simulation. The deflection, the particle velocity and the particle acceleration of the arch inwall and stress curves versus time are obtained comparing properties of blast resistance of different arch structures with the same amount of charge. The results show that the arch structure composed of foam concrete-SFRC-steel has good blast resistance. furthermore, the dynamic performance of the foam concrete-SFRC-steel composite structures is studied with different amount of charge. Additionally, coupling relationship of blast resistance and explosion charge is analysed. Comparison of numerical results with experimental results, show that they are in good agreement. This numerical analysis may provide important guidance for blastresistant design and analysis of underground structures.Defence Science Journal, 2009, 59(2, pp.131-136, DOI:http://dx.doi.org/10.14429/dsj.59.1500

  18. Kilconnell Franciscan Friary, north chancel wall, tomb niche, jamb and arch

    OpenAIRE

    O'Donovan, Danielle

    2001-01-01

    Jamb and arch moulding of canopied niche in north chancel wall. Moulding from intrados comprises: quadrant, hollow chamfer, quadrant, flat surface running into hollow, mitre, hollow chamfer, quadrant, hollow chamfer.

  19. Timoleague Franciscan Friary, north nave wall, tomb niche, jamb, arch and hood

    OpenAIRE

    O'Donovan, Danielle

    2004-01-01

    Jamb, arch and hood moulding of tomb niche. From intrados, moulding comprises quardant, right-angled rebate, quadrant. The hood, from outer moulding to inner, comprises a frontal fillet, hollow chamfer quadrant.

  20. Computed tomography angiography of hybrid thoracic endovascular aortic repair of the aortic arch.

    Science.gov (United States)

    Akhtar, Nila J; Oderich, Gustavo S; Vrtiska, Terri J; Williamson, Eric E; Araoz, Philip A

    2013-05-01

    Endovascular repair of the aorta has traditionally been limited to the abdominal aorta and, more recently, the descending thoracic aorta. However, recently hybrid repairs (a combination of open surgical and endovascular repair) have made endovascular repair of the aortic arch possible. Hybrid repair of the aortic arch typically involves an open surgical debranching procedure that allows for revascularization of the aortic arch vessels and subsequent endovascular stent placement. These approaches avoid the deep hypothermic circulatory arrest required for full, open surgical repair of the aortic arch. In hybrid repairs, the stent landing zone determines which branch vessels will be covered and therefore need revascularization. This article will review the preprocedure assessment with computed tomography angiography, techniques for revascularization and postprocedure complications. PMID:23621141

  1. Patterns of attachment of the myodural bridge by the rectus capitis posterior minor muscle.

    Science.gov (United States)

    Yuan, Xiao-Ying; Yu, Sheng-Bo; Li, Yun-Fei; Chi, Yan-Yan; Zheng, Nan; Gao, Hai-Bin; Luan, Bing-Yi; Zhang, Zhao-Xi; Sui, Hong-Jin

    2016-03-01

    The myodural bridge was first described by Hack in 1995 and was thought to be related to chronic cervicogenic headaches. For a long time, few studies revealed the patterns of the myodural bridge considering the rectus capitis posterior minor muscle. In this study, P45 plastination technology and anatomical dissection were performed on head specimens, and four different terminal region types of the rectus capitis posterior minor muscle were observed, including the posterior atlanto-occipital interspace, posterior arch of the atlas and posterior atlanto-axial interspace. We propose that the myodural complex structures in the posterior atlanto-occipital and posterior atlanto-axial interspace have cooperative effects on cerebrospinal fluid and work together. This force might be an important source for the circulation of cerebrospinal fluid. PMID:25859757

  2. In-service performance and behavior characterization of the hybrid composite bridge system - a case study

    CERN Document Server

    Civitillo, John M; Gheitasi, Amir; Saliba, Mark; Kassner, Bernard L

    2014-01-01

    The Hybrid Composite Beam (HCB) system is an innovative structural technology that has been recently used in bridge construction within the U.S. transportation network. In this system, the superstructure consists of a conventional reinforced concrete deck supported by Hybrid Composite Beams. Each beam is comprised of a glassfiber reinforced polymer (FRP) box shell containing a tied parabolic concrete arch. Inclined stirrups provide shear integrity and enforce composite action between the HCBs and the concrete deck. This paper focuses on evaluating the in-service performance of a newly constructed HCB bridge superstructure located on Route 205 in Colonial Beach, Virginia. A live load test was conducted using tandem axle dump trucks under both quasi-static and dynamic conditions. Results obtained from the experimental investigation were used to determine three key behavior characteristics. Dynamic amplification and lateral load distribution were found to be reasonable in comparison to the assumed design values....

  3. Unusual Displacement of a Mobilised Dental Bridge during Orotracheal Intubation

    Directory of Open Access Journals (Sweden)

    Paolo Feltracco

    2011-01-01

    Full Text Available Dental trauma during tracheal intubation mostly happens in case of poor dentition, restricted mouth opening, and/or difficult laryngoscopy. 57-year-old man undergoing laparoscopic radiofrequency ablation of unresectable hepatocellular carcinoma had his dental work detached at induction of anesthesia. Oropharyngeal direct view, manual inspection, fibreoptic nosendoscopy, tracheobronchoscopy, and fiberoptic inspection of the esophagus and stomach were unsuccessful in locating the dislodged bridge. While other possible exams were considered, such as lateral and AP x-ray of head and neck, further meticulous manual “sweepings” of the mouth were performed, and by moving the first and second fingers below the soft palate deep towards the posterolateral wall of the pharynx, feeling consistent with a dental prosthesis was detected in the right pharyngeal recess. Only after pulling the palatopharyngeal arch upward was it possible to grasp it and extract it out with the aid of a Magill Catheter Forceps. Even though the preexisting root and bridge deficits were well reported by the consultant dentist, the patient was fully reimbursed. The lack of appropriate documentation of the advanced periodontal disease in the anesthesia records, no mention of potential risks on anesthesia consent, and insufficient protective measures during airway instrumentation reinforced the reimbursement claim.

  4. Stationarity and geometric ergodicity of a class of nonlinear ARCH models

    OpenAIRE

    Saidi, Youssef; Zakoian, Jean-Michel

    2006-01-01

    A class of nonlinear ARCH processes is introduced and studied. The existence of a strictly stationary and $\\beta$-mixing solution is established under a mild assumption on the density of the underlying independent process. We give sufficient conditions for the existence of moments. The analysis relies on Markov chain theory. The model generalizes some important features of standard ARCH models and is amenable to further analysis.

  5. Dermatoglyphic Assessment in Subjects with Different Dental Arch Forms: An Appraisal

    OpenAIRE

    Sachdeva, Shabina; Tripathi, Arvind; Kapoor, Pranav

    2013-01-01

    Successful rehabilitation of edentulous individuals involves selection and arrangement of artificial teeth in accordance with the patient’s original arch form. Various criteria exist for harmonious tooth arrangement but none is accepted universally. Finger and palm prints are unique to an individual and once formed in the sixth week of intra-uterine life, remain constant thereafter. Since dental arches are also formed during the same prenatal period, it is believed that the similar genetic fa...

  6. Comparison of arch form between ethnic Malays and Malaysian Aborigines in Peninsular Malaysia

    OpenAIRE

    Othman, Siti Adibah; Xinwei, Eunice Soh; Lim, Sheh Yinn; Jamaludin, Marhazlinda; Mohamed, Nor Himazian; Yusof, Zamros Yuzaidi Mohd; Shoaib, Lily Azura; Nik Hussein, Nik Noriah

    2012-01-01

    Objective: To determine and compare the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups. Methods: We examined 120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular). We marked 18 buccal tips and incisor line angles on each model, and digitized them using 2-dimens...

  7. Continuum analysis of common branching patterns in the human arch of the aorta.

    Science.gov (United States)

    Zamir, M; Sinclair, P

    1990-01-01

    A model is proposed for describing common variations in the arrangement of branches on the arch of the human aorta, and the model is used to analyze data from 123 human arches. The analysis allows the observed variations to fall freely along a continuous spectrum, rather than be confined to discrete categories as is commonly done at present. The results thus describe these variations in a more natural way and throw some new light on their likely source.

  8. Comparison Of Medial Arch-Supporting Insoles And Heel Pads In The Treatment Of Plantar Fasciitis

    Directory of Open Access Journals (Sweden)

    Malkoc Melih

    2015-03-01

    Full Text Available Plantar fasciitis is a disorder caused by inflammation of the insertion point of the plantar fascia over the medial tubercle of the calcaneus. Foot orthotics are used to treat plantar fasciitis. Heel pads medialise the centre of force, whereas medial arch supporting insoles lateralise the force. We assessed the clinical results of the treatment of plantar fasciitis with silicone heel pads and medial arch-supported silicone insoles.

  9. Dentures as Learning Materials for Maxillomandibular Fixation by Erich Arch Bars.

    Science.gov (United States)

    Aksam, Ersin; Aksam, Berrak

    2016-03-01

    Maxillomandibular fixation with Erich arch bars is an economic method for handling mandibular fractures. Unfortunately, this method has some disadvantages, such as long operating time, periodontal trauma, and risk of puncture injury to the operator. To overcome these disadvantages, we propose teaching the pits and pearls of maxillomandibular fixation with Erich arch bars to trainees using dentures of a patient. Experiencing the method on dentures will shorten the learning curve.

  10. ARCH and GARCH Models vs. Martingale Volatility of Finance Market Returns

    OpenAIRE

    Joseph L. McCauley

    2008-01-01

    ARCH and GARCH models assume either i.i.d. or (what economists lable as) white noise as is usual in regression analysis while assuming memory in a conditional mean square fluctuation with stationary increments. We will show that ARCH/GARCH is inconsistent with uncorrelated increments, violating the i.i.d. and white assumptions and finance data and the efficient market hypothesis as well.

  11. Evaluation of arch width variations among different skeletal patterns in South Indian population

    OpenAIRE

    Prasad, Mandava; Kannampallil, Senny Thomas; Talapaneni, Ashok Kumar; George, Suja Ani; Shetty, Sharath Kumar

    2013-01-01

    Background: Anterior cranial base can be taken as a reference line (SN) to determine the steepness of mandibular plane. Subjects with high mandibular plane angle tend to have a long face and one with low MP-SN angle has a shorter face. Objective: This study was done to investigate if dental arch widths correlated with vertical facial types and if there are any differences in arch widths between untreated male and female adults in South Indian population. Materials and Methods: Lateral cephalo...

  12. Calculation and Analysis of Internal Force in Arch Structure of Frozen Soil

    Institute of Scientific and Technical Information of China (English)

    YUE Feng-tian; ZHANG Yong; SHI Rong-jian

    2005-01-01

    Aimed at the frozen soil arch reinforcement form of upside shed used for the shield machine launching in tunneling the internal force of the structure was calculated with the aid of the structural mechanics theory. Considering the space characteristics of the structure,this calculating method is suitable for practical engineering.Moreover,the behavior of the freezing arch reinforcement structure was analyzed combined with an engineering case.

  13. Edentulism and shortened dental arch in Brazilian elderly from the National Survey of Oral Health 2003

    Directory of Open Access Journals (Sweden)

    Marco Túlio Freitas Ribeiro

    2011-10-01

    Full Text Available OBJECTIVE: To describe the distribution of edentulism and estimate the prevalence of functional dentition and shortened dental arch among elderly population. METHODS: A population-based epidemiological study was carried out with a sample of 5,349 respondents aged 65 to 74 years obtained from the 2002 and 2003 Brazilian Ministry of Health/Division of Oral Health survey database. The following variables were studied: gender; macroregion of residence; missing teeth; percentage that met the World Health Organization goal for oral health in the age group 65 to 74 years (50% having at least 20 natural teeth; presence of shortened dental arch; number of posterior occluding pairs of teeth. The Chi-square test assessed the association between categorical variables. The Kruskal-Wallis and Mann-Whitney tests were used to assess differences of mean between number of posterior occluding pairs teeth, macro-region and gender. RESULTS: The elderly population had an average of 5.49 teeth (SD: 7.93 with a median of 0. The proportion of completely edentulous respondents was 54.7%. Complete edentulism was 18.2% in the upper arch and 1.9% in the lower arch. The World Health Organization goal was achieved in 10% of all respondents studied. However, only 2.7% had acceptable masticatory function and aesthetics (having at least shortened dental arch and a mean number of posterior occluding pairs of 6.94 (SD=2.97. There were significant differences of the percentage of respondents that met the World Health Organization goal and presence of shortened dental arch between men and women. There were differences in shortened dental arch between macroregions. CONCLUSIONS: The Brazilian epidemiological oral health survey showed high rate of edentulism and low rate of shortened dental arch in the elderly population studied, thus suggesting significant functional and aesthetic impairment in all Brazilian macroregions especially among women.

  14. 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...

  15. Geology of the Juanita Arch quadrangle, Mesa county, Colorado

    Science.gov (United States)

    Shoemaker, Eugene M.

    1954-01-01

    The Juanita Arch quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore ro large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstone of favorable construction.

  16. The massive star Initial Mass Function of the Arches cluster

    CERN Document Server

    Espinoza, Pablo; Melnick, Jorge

    2009-01-01

    The massive Arches cluster near the Galactic Center is in principle an ideal laboratory to investigate massive star formation under extreme conditions. But it comes at a high price: the cluster is hidden behind several tens of magnitudes of visual extinction. Severe crowding requires space or AO-assisted instruments to resolve the stellar populations, and even with the best instruments the interpretation of the data is far from direct. Several investigations using NICMOS and the most advanced AO imagers on the gro und revealed an overall top-heavy IMF for the cluster, with a very flat IMF near the center. There are a number of effects, however, that could potentially bias these results, in particular the strong differential extinction and the problem of transforming the observations to a standard photometric system in the presence of strong reddening. We present new observations obtained with the NAOS-Conica (NACO) AO-imager on the VLT. The problem of photometric transformation is avoided by working in the na...

  17. Correlation between maxillary central incisor crown morphology and mandibular dental arch form in normal occlusion subjects.

    Science.gov (United States)

    Paranhos, Luiz Renato; Lima, Carolina Souto; da Silva, Ricardo Henrique Alves; Daruge Júnior, Eduardo; Torres, Fernando Cesar

    2012-01-01

    The aim of this study was to evaluate the correlation between the morphology of the mandibular dental arch and the maxillary central incisor crown. Cast models from 51 Caucasian individuals, older than 15 years, with optimal occlusion, no previous orthodontic treatment, featuring 4 of the 6 keys to normal occlusion by Andrews (the first being mandatory) were observed. The models were digitalized using a 3D scanner, and images of the maxillary central incisor and mandibular dental arch were obtained. These were printed and placed in an album below pre-set models of arches and dental crowns, and distributed to 12 dental surgeons, who were asked to choose which shape was most in accordance with the models and crown presented. The Kappa test was performed to evaluate the concordance among evaluators while the chi-square test was used to verify the association between the dental arch and central incisor morphology, at a 5% significance level. The Kappa test showed moderate agreement among evaluators for both variables of this study, and the chi-square test showed no significant association between tooth shape and mandibular dental arch morphology. It may be concluded that the use of arch morphology as a diagnostic method to determine the shape of the maxillary central incisor is not appropriate. Further research is necessary to assess tooth shape using a stricter scientific basis. PMID:22666773

  18. Size-dependent bistability of an electrostatically actuated arch NEMS based on strain gradient theory

    International Nuclear Information System (INIS)

    This paper deals with the investigation of the size-dependent nature of nonlinear dynamics, in a doubly clamped shallow nano-arch actuated by spatially distributed electrostatic force. We employ strain gradient theory together with the Euler–Bernoulli and shallow arch assumptions in order to derive the nonlinear partial differential equation governing the transverse motion of the arch with mid-plane stretching effects. Using the Galerkin projection method, we derive the lumped single degree of freedom model which is then used for the study of the size effects on the nonlinear snap-through and pull-in instabilities of the arch nano-electro-mechanical-system (NEMS). Moreover, using strain gradient theory, the size-dependent bistability and fundamental frequencies of the nano-arch are scrutinized, revealing that, despite what is predicted by the classical theory, the bistability region in the parameter space of the nano-structure shrinks as the structure scales down. Also, we show that the minimum initial elevation, required for bistability, increases as the nano-arch scales down. (paper)

  19. Analysis of the pedestrian arching at bottleneck based on a bypassing behavior model

    Science.gov (United States)

    Tang, Ming; Jia, Hongfei; Ran, Bin; Li, Jun

    2016-07-01

    A bypassing behavior model was proposed, in which the local optimal decision behavior in the strategy level was modeled in velocity-time domain, to describe how pedestrians bypass the local obstacles considering the relative speed. The model contains (1) pedestrian visual and contact information acquisition; (2) motion state prediction of the local obstacles based on the visual and contact information; (3) pedestrian bypass strategy modeling in the velocity-time domain; (4) moving and overlapping solution. In the numerical solution, velocity domain was divided into n equal angle, the value of n ranges from 2 to infinity, the Manhattan space was refined gradually to Euclid Space accordingly, in which the movement of pedestrians was described. The model was applied to the analysis of pedestrian arching at the bottleneck in the emergent evacuation situation. (1) The results showed that the formation of the pedestrian arching at the bottleneck was deformation pressure, because many pedestrians try to pass through the bottleneck simultaneously, even in the absence of friction, the pedestrian arching still occurs; (2) In the emergent situation, we are more concerned about the bottleneck attribution of resistance to form the arching, the calculation and simulation results showed that the probability of an arching and the bottleneck width is an exponential function relationship, so when the stampede occurs in the middle of the bottleneck, the probability of arching will increase exponentially.

  20. SOFIA/FORCAST Observations of the Arched Filamentary Region in the Galactic Center

    Science.gov (United States)

    Hankins, Matthew; Lau, Ryan M.; Morris, Mark; Herter, Terry L.

    2016-06-01

    Abstract: We present 19.7, 25.2, 31.5, and 37.1 μm maps of the Thermal Arched Filament region in the Galactic Center taken with the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST) with an angular resolution of 3.2-3.8". We calculate the integrated infrared luminosity of the Arched Filaments and show that they are consistent with being heated by the nearby Arches cluster. Additionally, using our observations, we infer dust temperatures (75 – 90 K) across the Arched Filaments which are remarkably consistent over large spatial scales (∼ 25 pc). We discuss the possible geometric effects needed to recreate this temperature structure. Additionally, we compare the observed morphology of the Arches in the FORCAST maps with the Paschen-α emission in the region to study what fraction of the infrared emission may be coming from dust in the HII region versus the PDR beneath it. Finally, we use Spitzer/IRAC 8 μm data to look for spatial variations in PAH abundance in the rich UV environment of the young (~2-4 Myr) and massive Arches cluster.

  1. Study on real working performance and overload safety factor of high arch dam

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Considering the fact that high arch dams have problems such as complicated stress,high cost,and hazards after being damaged,this paper intends to study the effects of load,material strength,and safety analysis method on dam safety and working performance of arch dams.In this article,the effects of temperature,self weight exaction way and water loading on structure response are first discussed,and a more reasonable way of considering is then put forward.By taking into consideration the mechanical property of materials and comparing the effects of different yield criteria on overloading safety of high arch dams,this paper concludes that brittle characteristics of concrete should be fully considered when conducting safety assessment for high arch dams to avoid overestimating the bearing capacity of the dams.By comparing several typical projects,this paper works out a safety assessment system of multiple safety and relevant engineering analogical analysis methods,which is closer to the actual situation,and thus is able to assess the response of high arch dam structure in a more comprehensive way,elicit the safety coefficients in different situations,and provide a new way of considering the safety assessment of high arch dams.

  2. Nonlinear simulation of arch dam cracking with mixed finite element method

    Directory of Open Access Journals (Sweden)

    Ren Hao

    2008-06-01

    Full Text Available This paper proposes a new, simple and efficient method for nonlinear simulation of arch dam cracking from the construction period to the operation period, which takes into account the arch dam construction process and temperature loads. In the calculation mesh, the contact surface of pair nodes is located at places on the arch dam where cracking is possible. A new effective iterative method, the mixed finite element method for friction-contact problems, is improved and used for nonlinear simulation of the cracking process. The forces acting on the structure are divided into two parts: external forces and contact forces. The displacement of the structure is chosen as the basic variable and the nodal contact force in the possible contact region of the local coordinate system is chosen as the iterative variable, so that the nonlinear iterative process is only limited within the possible contact surface and is much more economical. This method was used to simulate the cracking process of the Shuanghe Arch Dam in Southwest China. In order to prove the validity and accuracy of this method and to study the effect of thermal stress on arch dam cracking, three schemes were designed for calculation. Numerical results agree with actual measured data, proving that it is feasible to use this method to simulate the entire process of nonlinear arch dam cracking.

  3. Prediction of Collapse Scope of Deep-Buried Tunnels Using Pressure Arch Theory

    Directory of Open Access Journals (Sweden)

    Yingchao Wang

    2016-01-01

    Full Text Available Tunnel collapse remains a serious problem in practice. Effective prediction methods on tunnel collapse are necessary for tunnel engineering. In this study, systematic study on the pressure arch was presented to predict tunnel collapse. Multiple factors under different conditions were considered. First, the pressure arch was described as a certain scope in comparison with the lowest pressure arch line. Then, a deep-buried circular tunnel was selected as the investigated object. Its collapse scope was analyzed using the lowest pressure arch line. Meanwhile, the main influence from the ground stress field was considered. Different modes of ground stress fields were investigated in detail. The results indicate that the collapse scope varies with different ground stress fields. Determination on the collapse scope is strongly affected by the judgment standard of the pressure arch. Furthermore, a selected case was analyzed with the pressure arch. The area and the height of tunnel collapse were calculated with multiple factors, including ground stress field, judgment standard, and lateral pressure coefficient. Finally, selected results were compared with relevant previous researches, and reasonable results were obtained. The present results are helpful for further understanding of the tunnel collapse and could provide suitable guidance for tunnel projects.

  4. Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam

    Science.gov (United States)

    Zhang, Jingkui; Zhang, Liaojun

    2014-06-01

    Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code (3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, influence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far field energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice.

  5. Dental crowding in primary dentition and its relationship to arch and crown dimensions among preschool children of Davangere.

    Science.gov (United States)

    Prabhakar, A R; Ravi, G R; Kurthukoti, Ameet J; Shubha, A B

    2008-01-01

    The purpose of the present study was to evaluate dental crowding in the deciduous dentition and its relationship to the crown and the arch dimensions among preschool children of Davangere. Stratified randomized selection of one hundred, 3-4 year old healthy children with all primary teeth erupted was done and divided into two groups. One group had children with anterior crowding in both the arches while the other had spacing. Alginate impressions of the upper and lower arches were made and the study casts were obtained. The tooth and arch dimensions were determined. Mesiodistal dimensions of all the teeth were significantly larger in the crowded arch group. However, the buccolingual dimensions of the maxillary right central incisor, mandibular lateral incisors and the maxillary molars and the crown shape ratio of maxillary lateral incisors, mandibular canines and mandibular right second molar was statistically different. No significant correlation was found between the arch width and the presence of crowding of deciduous dentition. The arch depth of the spaced dentition was greater when compared to the crowded ones. The arch perimeter of the crowded arches was significantly less than the spaced arches.

  6. Theory of bridge aerodynamics

    CERN Document Server

    Strømmen, Einar

    2006-01-01

    This text book is intended for studies in wind engineering, with focus on the stochastic theory of wind induced dynamic response calculations for slender bridges or other line ?like civil engineering type of structures. It contains the background assumptions and hypothesis as well as the development of the computational theory that is necessary for the prediction of wind induced fluctuating displacements and cross sectional forces. The simple cases of static and quasi-static structural response calculations are for the sake of completeness also included. The text is at an advanced level in the

  7. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

    The UK has a long history in the railway industry with a large number of railway assets. Railway bridges form one of the major asset groups with more than 35,000 bridges. The majority of the bridge population are old being constructed over 100 years ago. Many of the bridges were not designed to meet the current network demand. With an expected increasing rate of deterioration due to the increasing traffic loads and intensities, the management authorities are faced with the difficult task of k...

  8. The randomized shortened dental arch study (RaSDA: design and protocol

    Directory of Open Access Journals (Sweden)

    Kern Matthias

    2010-02-01

    Full Text Available Abstract Background Various treatment options for the prosthetic treatment of jaws where all molars are lost are under discussion. Besides the placement of implants, two main treatment types can be distinguished: replacement of the missing molars with removable dental prostheses and non-replacement of the molars, i.e. preservation of the shortened dental arch. Evidence is lacking regarding the long-term outcome and the clinical performance of these approaches. High treatment costs and the long time required for the treatment impede respective clinical trials. Methods/design This 14-center randomized controlled investigator-initiated trial is ongoing. Last patient out will be in 2010. Patients over 35 years of age with all molars missing in one jaw and with at least both canines and one premolar left on each side were eligible. One group received a treatment with removable dental prostheses for molar replacement (treatment A. The other group received a treatment limited to the replacement of all missing anterior and premolar teeth using fixed bridges (treatment B. A pilot trial with 32 patients was carried out. Two hundred and fifteen patients were enrolled in the main trial where 109 patients were randomized for treatment A and 106 for treatment B. The primary outcome measure is further tooth loss during the 5-year follow-up. The secondary outcome measures encompassed clinical, technical and subjective variables. The study is funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG WA 831/2-1, 2-2, 2-3, 2-4, 2-5. Discussion The particular value of this trial is the adaptation of common design components to the very specific features of complex dental prosthetic treatments. The pilot trial proved to be indispensable because it led to a number of adjustments in the study protocol that considerably improved the practicability. The expected results are of high clinical relevance and will show the efficacy of two common

  9. Proper motions of the Arches cluster with Keck-LGS Adaptive Optics: the first kinematic mass measurement of the Arches

    CERN Document Server

    Clarkson, Will; Morris, Mark; Lu, Jessica; Stolte, Andrea; McCrady, Nate; Do, Tuan; Yelda, Sylvana

    2011-01-01

    We report the first detection of the intrinsic velocity dispersion of the Arches cluster - a young (~2 Myr), massive (~10,000 Solar Mass) starburst cluster located near the Galactic center. This was accomplished using proper motion measurements within the central region of the cluster, obtained with the laser guide star adaptive optics system at Keck Observatory over a 3 year time baseline (2006-2009). This uniform dataset results in proper motion measurements that are improved by a factor ~5 over previous measurements from heterogeneous instruments, yielding internal velocity dispersion estimates 0.15 +/- 0.01 mas/yr, which corresponds to 5.4 +/- 0.4 km/s at a distance of 8.4 kpc. Projecting a simple model for the cluster onto the sky to compare with our proper motion dataset, in conjunction with surface density data, we estimate the total present-day mass of the cluster to be 15,000 (+7400 -6000) Solar masses. The mass in stars observed within a cylinder of radius R=0.4 pc is found to be 9000 (+4000 -3500) ...

  10. 张家口市清水河工业南桥荷载试验分析%Load Test Analysis of Industrial South Bridge over Qingshui River in Zhangjiakou City

    Institute of Scientific and Technical Information of China (English)

    刘剑

    2014-01-01

    张家口市清水河工业南桥属于钢结构下承式系杆拱桥。采用Madis Civil有限元软件对该桥的承载能力进行了分析计算,介绍了该种结构桥梁的静载、动载情况及施工方案,为相关桥梁荷载试验分析积累经验。%Industrial South Bridge over Qingshui River in Zhangjiakou City is a typical steel-structure through tied-arch bridge.This paper analyzes and calculates the bearing capacity of the bridge using Mad-is Civil finite element software. Moreover, the paper introduces the static load, dynamic load and related construction scheme of this bridge. It hopes to accumulate experience for relevant bridge load test analy-sis.

  11. Foot medial longitudinal-arch deformation during quiet standing and gait in subjects with medial tibial stress syndrome

    DEFF Research Database (Denmark)

    Bandholm, Thomas Quaade; Boysen, Lisbeth; Haugaard, Stine;

    2008-01-01

    . Medial longitudinal-arch deformation was measured during walking gait using 3-dimensional gait analysis. Subjects with medial tibial stress syndrome demonstrated a significantly larger navicular drop (mean +/- 1 SD, 7.7 +/- 3.1 mm) and medial longitudinal-arch deformation (5.9 +/- 3.2 degrees) during...... and increased medial longitudinal-arch deformation during gait compared to healthy subjects. Medial longitudinal-arch deformation during quiet standing did not correlate with medial longitudinal-arch deformation during gait in either of the 2 groups. ACFAS Level of Clinical Evidence: 5 Udgivelsesdato: 2008/3......The objective of this study was to investigate (1) if subjects with medial tibial stress syndrome demonstrate increased navicular drop and medial longitudinal-arch deformation during quiet standing and gait compared with healthy subjects, and (2) the relationship between medial longitudinal...

  12. Numerical analyses in the design of umbrella arch systems

    Institute of Scientific and Technical Information of China (English)

    J. Oke; N. Vlachopoulos; M.S. Diederichs

    2014-01-01

    Due to advances in numerical modelling, it is possible to capture complex support-ground interaction in two dimensions and three dimensions for mechanical analysis of complex tunnel support systems, although such analysis may still be too complex for routine design calculations. One such system is the forepole element, installed within the umbrella arch temporary support system for tunnels, which warrants such support measures. A review of engineering literature illustrates that a lack of design standards exists regarding the use of forepole elements. Therefore, when designing such support, de-signers must employ complex numerical models combined with engineering judgement. With reference to past developments by others and new investigations conducted by the authors on the Driskos tunnel in Greece and the Istanbul metro, this paper illustrates how advanced numerical modelling tools can facilitate understanding of the influences of design parameters associated with the use of forepole ele-ments. In addition, this paper highlights the complexity of the ground-support interaction when simulated with two-dimensional (2D) finite element software using a homogenous reinforced region, and three-dimensional (3D) finite difference software using structural elements. This paper further il-lustrates sequential optimisation of two design parameters (spacing and overlap) using numerical modelling. With regard to capturing system behaviour in the region between forepoles for the purpose of dimensioning spacing, this paper employs three distinctive advanced numerical models:particle codes, continuous finite element models with joint set and Voronoi blocks. Finally, to capture the behaviour/failure ahead of the tunnel face (overlap parameter), 2D axisymmetric models are employed. Finally, conclusions of 2D and 3D numerical assessment on the Driskos tunnel are drawn. The data enriched case study is examined to determine an optimum design, based on the proposed optimisation of

  13. Role of aortic arch vascular mechanics in cardiovagal baroreflex sensitivity.

    Science.gov (United States)

    Klassen, Stephen A; Chirico, Daniele; Dempster, Kylie S; Shoemaker, J Kevin; O'Leary, Deborah D

    2016-07-01

    Cardiovagal baroreflex sensitivity (cvBRS) measures the efficiency of the cardiovagal baroreflex to modulate heart rate in response to increases or decreases in systolic blood pressure (SBP). Given that baroreceptors are located in the walls of the carotid sinuses (CS) and aortic arch (AA), the arterial mechanics of these sites are important contributors to cvBRS. However, the relative contribution of CS and AA mechanics to cvBRS remains unclear. This study employed sex differences as a model to test the hypothesis that differences in cvBRS between groups would be explained by the vascular mechanics of the AA but not the CS. Thirty-six young, healthy, normotensive individuals (18 females; 24 ± 2 yr) were recruited. cvBRS was measured using transfer function analysis of the low-frequency region (0.04-0.15 Hz). Ultrasonography was performed at the CS and AA to obtain arterial diameters for the measurement of distensibility. Local pulse pressure (PP) was taken at the CS using a hand-held tonometer, whereas AA PP was estimated using a transfer function of brachial PP. Both cvBRS (25 ± 11 vs. 19 ± 7 ms/mmHg, P = 0.04) and AA distensibility (16.5 ± 6.0 vs. 10.5 ± 3.8 mmHg(-1) × 10(-3), P = 0.02) were greater in females than males. Sex differences in cvBRS were eliminated after controlling for AA distensibility (P = 0.19). There were no sex differences in CS distensibility (5.32 ± 2.3 vs. 4.63 ± 1.3 mmHg(-1) × 10(-3), P = 0.32). The present data demonstrate that AA mechanics are an important contributor to differences in cvBRS.

  14. 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

  15. 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

  16. A Comparison Study of Stress Distribution Around Dental Implants in Three Mandibular Arch Types by Finite lement Analysis

    OpenAIRE

    Monzavi A.; Farhang Gh R

    2000-01-01

    The geometric shape of dental arch (square, tapering, ovoid) is an important factor in stress distribution pattern around dental implant. The aim of this study was to evaluate the role of arch form and the amount of bone loss (normal, moderate, high) in stress distribution around dental implant by considering different load direction. Three arch forms; square, ovoid, and tapering with three different stages of bone loss were designed. Models were divided into three-dimensional elements, which...

  17. Aortic arch thrombectomy in a 2.8 kilogram neonate--a case report and review of the literature.

    Science.gov (United States)

    Omeje, Ikenna; Ram, Awat; Kostolny, Martin

    2013-02-01

    Aortic arch thrombus is a rare occurrence in neonates. In the few described cases, this has mainly been associated with sepsis or early postnatal interventions, such as insertion of umbilical arterial line. We describe a case of occlusive aortic arch thrombus in a neonate who presented with signs of critical coarctation and successfully underwent surgical thrombectomy on deep hypothermic circulatory arrest. We also present a review of the most recently published cases of aortic arch thrombus in neonates and the treatment options employed.

  18. Dental arch dimensions in the mixed dentition: a study of Brazilian children from 9 to 12 years of age

    OpenAIRE

    Fabiane Louly; Paulo Roberto Aranha Nouer; Guilherme Janson; Arnaldo Pinzan

    2011-01-01

    OBJECTIVE: This study evaluated dental arch dimensional changes of Brazilian children. MATERIAL AND METHODS: Dental casts were taken from 66 children (29 males; 37 females) with normal occlusion selected among 1,687 students from public and private schools aged 9, 10, 11 and 12 years, according to the following criteria: Class I canine and molar relationships; well-aligned upper and lower dental arches; mixed dentition; good facial symmetry; no previous orthodontic treatment. Dental arch dime...

  19. 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.

  20. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

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

  1. MATHEMATICAL ANALYSIS OF DENTAL ARCH OF CHILDREN IN NORMAL OCCLUSION: A LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    M. Abu-Hussein DDS, MScD, MSc, DPD

    2012-03-01

    Full Text Available AIM. This paper is an attempt to compare and analyze the various mathematical models for defining the dental arch curvature of children in normal occlusion based upon a review of available literature. Background. While various studies have touched upon ways to cure or prevent dental diseases and upon surgical ways for teeth reconstitution to correct teeth anomalies during childhood, a substantial literature also exists, attempting to mathematically define the dental arch of children in normal occlusion. This paper reviews these dental studies and compares them analytically. Method. The paper compares the different mathematical approaches, highlights the basic assumptions behind each model, underscores the relevancy and applicability of the same, and also lists applicable mathematical formulae. Results. Each model has been found applicable to specific research conditions, as a universal mathematical model for describing the human dental arch still eludes satisfactory definition. The models necessarily need to include the features of the dental arch, such as shape, spacing between teeth and symmetry or asymmetry, but they also need substantial improvement. Conclusions. While the paper shows that the existing models are inadequate in properly defining the human dental arch, it also acknowledges that future research based on modern imaging techniques and computeraided simulation could well succeed in deriving an allinclusive definition for the human dental curve till now eluding the experts.

  2. Rearfoot alignment and medial longitudinal arch configurations of runners with symptoms and histories of plantar fasciitis

    Directory of Open Access Journals (Sweden)

    Ana Paula Ribeiro

    2011-01-01

    Full Text Available OBJECTIVE: To evaluate and compare rearfoot alignment and medial longitudinal arch index during static postures in runners, with and without symptoms and histories of plantar fasciitis (PF. INTRODUCTION: PF is the third most common injury in runners but, so far, its etiology remains unclear. In the literature, rearfoot misalignment and conformations of the longitudinal plantar arch have been described as risk factors for the development of PF. However, in most of the investigated literature, the results are still controversial, mainly regarding athletic individuals and the effects of pain associated with these injuries. METHODS: Forty-five runners with plantar fasciitis (30 symptomatic and 15 with previous histories of injuries and 60 controls were evaluated. Pain was assessed by a visual analogue scale. The assessment of rearfoot alignment and the calculations of the arch index were performed by digital photographic images. RESULTS: There were observed similarities between the three groups regarding the misalignments of the rearfoot valgus. The medial longitudinal arches were more elevated in the group with symptoms and histories of PF, compared to the control runners. CONCLUSIONS: Runners with symptoms or histories of PF did not differ in rearfoot valgus misalignments, but showed increases in the longitudinal plantar arch during bipedal static stance, regardless of the presence of pain symptoms.

  3. Children with flat feet have weaker toe grip strength than those having a normal arch

    Science.gov (United States)

    Tashiro, Yuto; Fukumoto, Takahiko; Uritani, Daisuke; Matsumoto, Daisuke; Nishiguchi, Shu; Fukutani, Naoto; Adachi, Daiki; Hotta, Takayuki; Morino, Saori; Shirooka, Hidehiko; Nozaki, Yuma; Hirata, Hinako; Yamaguchi, Moe; Aoyama, Tomoki

    2015-01-01

    [Purpose] This study investigated the relationship between toe grip strength and foot posture in children. [Subjects and Methods] A total of 619 children participated in this study. The foot posture of the participants was measured using a foot printer and toe grip strength was measured using a toe grip dynamometer. Children were classified into 3 groups; flatfoot, normal, and high arch, according to Staheli’s arch index. The differences in demographic data and toe grip strength among each foot posture group were analyzed by analysis of variance. Additionally, toe grip strength differences were analyzed by analysis of covariance, adjusted to body mass index, age, and gender. [Results] The number of participants classified as flatfoot, normal, and high arch were 110 (17.8%), 468 (75.6%), and 41 (6.6%), respectively. The toe grip strength of flatfoot children was significantly lower than in normal children, as shown by both analysis of variance and analysis of covariance. [Conclusion] A significant difference was detected in toe grip strength between the low arch and normal foot groups. Therefore, it is suggested that training to increase toe grip strength during childhood may prevent the formation of flat feet or help in the development of arch. PMID:26696732

  4. The proper motion of the Arches cluster with Keck Laser-Guide Star Adaptive Optics

    CERN Document Server

    Stolte, Andrea; Morris, Mark; Lu, Jessica R; Brandner, Wolfgang; Matthews, Keith

    2007-01-01

    We present the first measurement of the proper motion of the young, compact Arches cluster near the Galactic center from near-infrared adaptive optics (AO) data taken with the recently commissioned laser-guide star (LGS) at the Keck 10-m telescope. The excellent astrometric accuracy achieved with LGS-AO provides the basis for a detailed comparison with VLT/NAOS-CONICA data taken 4.3 years earlier. Over the 4.3 year baseline, a spatial displacement of the Arches cluster with respect to the field population is measured to be 24.0 +/- 2.2 mas, corresponding to a proper motion of 5.6 +/- 0.5 mas/yr or 212 +/- 20 km/s at a distance of 8 kpc. In combination with the known radial velocity of the cluster, we derive a 3D space motion of 232 +/- 22 km/s of the Arches relative to the field. The large proper motion of the Arches cannot be explained with any of the closed orbital families observed in gas clouds in the bar potential of the inner Galaxy, but would be consistent with the Arches being on a transitional trajec...

  5. The Origin of the Dust Arch in the Halo of NGC 4631 An Expanding Superbubble?

    CERN Document Server

    Taylor, C L; Taylor, Christopher L.

    2003-01-01

    We study the nature and the origin of the dust arch in the halo of the edge-on galaxy NGC 4631 detected by Neininger & Dumke (1999). We present CO observations made using the new On-The-Fly mapping mode with the FCRAO 14m telescope, and find no evidence for CO emission associated with the dust arch. Our examination of previously published HI data shows that if previous assumptions about the dust temperature and gas/dust ratio are correct, then there must be molecular gas associated with the arch, below our detection threshold. If this is true, then the molecular mass associated with the dust arch is between 1.5 x 10^8 M(sun)and 9.7 x 10^8 M(sun), and likely towards the low end of the range. A consequence of this is that the maximum allowed value for the CO-to-H_2 conversion factor is 6.5 times the Galactic value, but most likely closer to the Galactic value. The kinematics of the HI apparently associated with the dust arch reveal that the gas here is not part of an expanding shell or outflow, but is inste...

  6. Study on Optimal Grouting Timing for Controlling Uplift Deformation of a Super High Arch Dam

    Science.gov (United States)

    Lin, Peng; Zhu, Xiaoxu; Li, Qingbin; Liu, Hongyuan; Yu, Yongjun

    2016-01-01

    A grouting model is developed for use during the grouting of the complex foundation of a super high arch dam. The purpose as to determine the optimal grouting timing and appropriate grouting pressure involved in controlling the uplift deformation of the dam. The model determines the optimal grouting time as the height of the arch dam increases with the concrete pouring, by checking the tensile stresses in the dam against standard specifications. The appropriate grouting pressures are given on the basis of the actual grouting pressures monitored during the upstream riverbed foundation grouting. An engineering procedure, applying the model, was then proposed and used during foundation grouting under the toe block of the Xiluodu super high-arch dam in south-western China. The quality of the foundation grouting was evaluated against the results from pressurized water permeability tests, acoustic wave velocity tests, elastic modulus tests and panoramic photographing of the rockmass on completion of the foundation grouting. The results indicated that the proposed grouting model can be applied to effectively reduce the uplift deformation and associated cracking risk for super high arch dams, and it can be concluded that the proposed engineering grouting procedure is a valuable tool for improving foundation grouting under the toe blocks of a super high arch dam.

  7. Study on Structure of Arched Longitudinal Beams of Deep Water Wharf

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    High-pile and beam-slab quays have been widely used after several years development. They are mature enough to be one of the most important structural types of wharves in China coastal areas. In order to accommodate large tonnage vessels, wharves should be constructed in deep water gradually. However, conventional high-pile and beam-slab structures are hard to meet the requirements of large deep-water wharf. According to arch's stress characteristics, a new type of wharf with catenary arched longitudinal beams is presented in this paper. The new wharf structure can make full use of arch's overhead crossing and reinforced concrete compression resistance, improve the interval between transverse bents greatly, and decrease underwater construction quantity. Thus, the construction cost cab be reduced. Take the third phase project of the Yangshan Deep-water Port for example, comparative analysis on catenary arched longitudinal beams and conventional longitudinal beams has been made. The result shows that with the same wharf length and width, the same loads and same longitudinal beam moment, catenary arch structure can improve the interval between bents up to 28 m, decrease the number of piles and underwater construction quantity.

  8. Liquid-Bridge Breaking Limits

    Science.gov (United States)

    Macner, Ashley; Steen, Paul

    2011-11-01

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

  9. Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

    Data.gov (United States)

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

  10. National Bridge Inventory - National Geospatial Data Asset (NGDA) Bridges

    Data.gov (United States)

    Department of Transportation — The NBI (NTAD 2015) is a collection of information (database) describing the more than 610,000 of the Nation's bridges located on public roads, including Interstate...

  11. Complex Testing of the Bridges

    Directory of Open Access Journals (Sweden)

    Savić Adrijana

    2016-01-01

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

  12. 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.

  13. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.; Nielsen, Anker;

    2013-01-01

    With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even...... if the window has an U-factor of 1 W/(m2·K) or lower. This paper describes the development of modern, energy efficient Danish windows with reduced thermal bridges. It focuses on materials, geometry, and sealing of window panes based on a literature review. Examples of modern windows are presented. Experience...

  14. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

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

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

  15. An Investigation into the Response of GFRP-Reinforced Glue-Laminated Tudor Arches

    Directory of Open Access Journals (Sweden)

    S. Alshurafa

    2012-01-01

    Full Text Available This paper presents the results of an experimental and computational investigation tailored to examine the response of glass fiber-reinforced-plastic-(GFRP- reinforced glue-laminated curved beams and arches. The main objective was to ascertain the viability of GFRP as an effective reinforcement for enhancing the load carrying capacity and stiffness of such curved structures. The study included optimization of the length and thickness of the GFRP reinforcement. In doing so, first a parametric finite element study was conducted to evaluate the influence of unidirectional GFRP reinforcement applied onto the arch using eleven possible configurations and different thicknesses. Subsequently, an experimental investigation was conducted to verify the results established by the finite element method as well as the integrity of actual GFRP-reinforced glue-laminated curved structures. The results indicate that GFRP can be considered as an effective and economically viable solution for strengthening and stiffening glulam arches, without adding any appreciable weight to the structure.

  16. Unilateral hyperplasia of the left posterior arch and associated vertebral schisis at C6 level

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, Giuseppe; Bonis, Pasquale de; Tamburrini, Gianpiero; Massimi, Luca; Rocco, Concezio di [Catholic University, School of Medicine, Department of Pediatric Neurosurgery, Rome (Italy); Byvaltsev, Vadim [Irkutsk Railway Clinical Hospital, Department of Neurosurgery, Irkutsk (Russian Federation); Leone, Antonio [Catholic University, School of Medicine, Department of Bioimaging and Radiological Sciences, Rome (Italy)

    2009-12-15

    We report on a 5-year-old girl with unilateral hyperplasia of the left posterior arch of C6 associated with spina bifida occulta at the same level. Anteroposterior and lateral radiographs of the cervical spine showed hypertrophy of the left lamina as well as overgrowth and elongation of the left spinous process of the sixth cervical vertebra. Computed tomography (CT) examination better depicted this congenital variant and clearly showed the associated schisis of the posterior arch at the same level. Magnetic resonance (MR) imaging examination ruled out other spinal anomalies. The neck pain, the young age of the patient and the local aesthetic abnormality contributed to the surgical indication. To the best of our knowledge, this is the first case in the English literature of unilateral hyperplasia of a posterior cervical arch. Only one previous study has reported a similar congenital anomaly, but it was limited to the left side of the spinous process. (orig.)

  17. The origin and significance of secondary flows in the aortic arch.

    Science.gov (United States)

    Black, M M; Hose, D R; Lawford, P V

    1995-01-01

    This paper comprises a study of the secondary flow patterns that can develop in the human aortic arch. Clinical evidence of these secondary flows has been obtained by Kilner et al. using magnetic resonance velocity mapping techniques. Some of their results are presented for comparison in this paper. Four difference parametric models of the aortic arch have been analysed using computational fluid dynamic techniques. Both steady and transient flow conditions have been considered and two different commercially available software packages were used, namely FIDAP and FLOTRAN. A satisfactory comparison of the theoretical analysis with the results, both in vivo and in vitro, obtained by Kilner et al. for their out-of-plane inlet model was found. The theoretical analysis can now be extended to analyse the effect of different configurations and orientations of artificial aortic valves on the resulting aortic arch flow patterns.

  18. Unilateral hyperplasia of the left posterior arch and associated vertebral schisis at C6 level

    International Nuclear Information System (INIS)

    We report on a 5-year-old girl with unilateral hyperplasia of the left posterior arch of C6 associated with spina bifida occulta at the same level. Anteroposterior and lateral radiographs of the cervical spine showed hypertrophy of the left lamina as well as overgrowth and elongation of the left spinous process of the sixth cervical vertebra. Computed tomography (CT) examination better depicted this congenital variant and clearly showed the associated schisis of the posterior arch at the same level. Magnetic resonance (MR) imaging examination ruled out other spinal anomalies. The neck pain, the young age of the patient and the local aesthetic abnormality contributed to the surgical indication. To the best of our knowledge, this is the first case in the English literature of unilateral hyperplasia of a posterior cervical arch. Only one previous study has reported a similar congenital anomaly, but it was limited to the left side of the spinous process. (orig.)

  19. Numerical simulation of damage in high arch dam due to earthquake

    Institute of Scientific and Technical Information of China (English)

    Hong ZHONG; Gao LIN; Hongjun LI

    2009-01-01

    Based on the assumption that concrete is macroscopic homogeneous, the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesos-cale. The bilinear damage evolution model and the damage evolution model expressed in power function with descending section are adopted to combine with the Mohr-Coulomb criterion with tension cut-off to investigate the crack development and fracture mode of high arch dams under the action of an earthquake. The analysis result of a high arch dam in China under design shows that cracks that take place in concrete are caused by excessive tensile stress. The cracks initiate at the middle of the dam top and distribute at the upper half of the dam while the rest of the parts remain intact. This conclusion agrees with the model test result.

  20. Theory and methods of global stability analysis for high arch dam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The global stability of high arch dam is one of the key problems in the safety study of arch dams,but no feasible method with theoretical basis is available.In this paper,based on the stability theory of mechanical system,it is demonstrated that the global failure of high arch dams belongs to a physical instability starting from local strength failure,which is the extreme point instability according to the characteristics of load-displacement curve obtained from the failure process of dam-foundation system. So the global failure of dam-foundation system should be studied with the stability theory of mechanical system.It is also pointed out that the current stability analysis methods used in engineering are consistent with the stability theory,but not established according to the mechanical system stability theory directly.A perfect method can be obtained through the study of physical disturbance equations.

  1. FLOOD DISCHARGE AND ENERGY DISSIPATION BY JETS FROM OUTLETS IN HIGH ARCH DAM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this thesis, the downstream local rock-bed scour by multiple layered jets and by the collision of water jets in vertical and transverse directions were studied and the stability of the inverted arch cushion pool were analyzed. The velocity distribution of an aerated jet running dwon in the pool is obtained, a new method to calculate the scour depth by multiple layered jets and by the collision of water jets was proposed, and a muthematical model to forecast the critical downstream depth as a slab with various specific gravity destructions was established. The results were verified by experimental research on the hydrodynamic pressure produced at gaps of the inverted arch type of wate cushion pool and by using an advanced measurement and the imitation method experiments on forces at both arch spandrels were carried out to find their characteristics.

  2. Research of air-cushion isolation effects on high arch dam reservoir

    Institute of Scientific and Technical Information of China (English)

    Shao-Jie Zhang; Jiang Chen; Yuan-Ze Zhang; Hao-Wu Liu

    2011-01-01

    A three-dimensional (3D) finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account.In this model,the displacement formulation in Lagrange method,pressure formulation in Euler method,nonlinear contact model based on Coulomb friction law are applied to the air-cushion,reservoir and contraction joint domain,respectively.The dynamic response of Jinping I arch dam with a height of 305m is analyzed using the seismic records of the Wenchuan Earthquake in 2008.Numerical resuits show that the air-cushion isolation reduces significantly the hydrodynamic pressure as well as the opening width for the contraction joints of high arch dam.

  3. Correlation analysis of craniomandibular index and gothic arch tracing in patients with craniomandibular disorders

    Directory of Open Access Journals (Sweden)

    Todić Jelena

    2011-01-01

    Full Text Available Background/Aim. Complex etiology and symptomatology of craniomandibular dysfunction make the diagnosing and therapy of this disorder more difficult. The aim of this work was to assess the value of clinical and instrumental functional analyses in diagnosing of this type of disorders. Methods. In this study 200 subjects were examined, 15 with temporomandibular joint disorder. They were subjected to clinical functional analysis (Fricton-Shiffman and instrumental functional analysis by using the method of gothic arch. The parameters of the gothic arch records were analyzed and subsequently compared among the subjects of the observed groups. Results. In the examined group of the population 7.5% of them were with craniomandibular dysfunction. The most frequent symptoms were sound in temporomandibular joint, painful sensitivity of the muscles on palpation and lateral turning of the lower jaw while opening the mouth. By analyzing the gothic arch records and comparing the obtained values between the observed groups it was assessed that: lateral and protrusion movements, lateral amplitude and the size of gothic arch were much bigger in the healthy subjects, and latero-lateral asymmetry was larger in the sick subjects. Latero-lateral dislocation of apex was recorded only in the sick subjects with average values of 0.22 ± 0.130 mm. The correlation between the values of Fricton-Shiffman craniomandibular index and the parameters of the gothic arch records and latero-lateral amplitude and dislocation of apex records were established by correlative statistical analysis. Conclusion. Functional analysis of orofacial system and instrumental analysis of lower jaw movements (gothic arch method can be recommended as precise and simple methods in diagnosing craniomandibular dysfunctions.

  4. CORRECTION OF ALVEOLAR ARCH MALALIGNMENT AFTER TOTAL CORRECTION IN UNILATERAL AND BILATERAL GR III CLEFTS

    Directory of Open Access Journals (Sweden)

    Mohana Rao

    2015-06-01

    Full Text Available AIMS AND OBJECTIVES: Aim of this study is to document and analyse the pre - operative and postoperative alveolar arch impressions . MATERIALS AND METHODS: 20 cases of both unilateral and bilateral GR III clefts selected for this study. These pati ents were operated at the age of not less than 9 months, preferably below the age of 18 months. Below the age of 9 months general condition of these children may not cope up the duration of general anesthesia and amount of surgical trauma. After intubating the patient preoperatively, with the help of custom made metal arch plates, at first, Medical grade Alginate material with optimal hydration used to get negative impression, from these , positive impressions were obtained by the use of optimally hydrated m edical grade stone powder routinely used by dental surgeons. These positive impressions along with negative impression s and metal plates allowed to settle down for 10 hours undisturbed, after that positive impressions retrieved carefully without breaking a nd stored for analysis. Similarly postoperative impressions were taken after a gap of 2 years in the same manner like that of pre - operative ones under general anesthesia. Both impressions w ere compared and analysis was done regarding alveolar arch malalign ment, asymmetry and arch collapse correction. RESULTS & CONCLUSION: The status of the alveolar arch after single stage operation for cleft lip and palate in the unilateral cleft was much improved and there was considerable correction of the arch collapse a s well; in the bilateral cleft the correction of the premaxillary protrusion was better appreciated than the degree of correction of the alveolar gap.

  5. Arch height change during sit-to-stand: an alternative for the navicular drop test

    Directory of Open Access Journals (Sweden)

    McPoil Thomas G

    2008-07-01

    Full Text Available Abstract Background A study was conducted to determine the reliability and validity of a new foot mobility assessment method that utilizes digital images to measure the change in dorsal arch height measured at 50% of the length of the foot during the Sit-to-Stand test. Methods Two hundred – seventy five healthy participants participated in the study. The medial aspect of each foot was photographed with a digital camera while each participant stood with 50% body weight on each foot as well as in sitting for a non-weight bearing image. The dorsal arch height was measured at 50% of the total length of the foot on both weight bearing and non-weight bearing images to determine the change in dorsal arch height. The reliability and validity of the measurements were then determined. Results The mean difference in dorsal arch height between non-weight bearing and weight bearing was 10 millimeters. The change in arch height during the Sit-to-Stand test was shown to have good to high levels of intra- and inter-reliability as well as validity using x-rays as the criterion measure. Conclusion While the navicular drop test has been widely used as a clinical method to assess foot mobility, poor levels of inter-rater reliability have been reported. The results of the current study suggest that the change in dorsal arch height during the Sit-to-Stand test offers the clinician a reliable and valid alternative to the navicular drop test.

  6. 涪陵乌江大桥复线桥船撞风险研究%Research on Ship Collision Risk of Double-line Bridge in Fuling Wujiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    曹佰杨; 李嵩林

    2016-01-01

    对拟建涪陵乌江大桥复线桥进行船撞风险研究.根据该桥桥址处的水流速度,典型水位,通航船舶密度、航速,通航净空尺度,航迹线以及桥梁的极限抗船撞能力等,采用三概率积分法,确定该桥拱圈碰撞频率和倒塌频率.另外,依据行业风险水平和风险评价矩阵,并结合三概率积分法计算结果来确定该桥船撞风险等级.%The paper studies ship collision risk of double-line bridge in Fuling Wujiang River Bridge to be constructed.In accordance with water flow rate,typical water level,navigation density and speed of ships,net clearance dimension of navigation,track line and limit resistance of bridge to ship collision, etc.,the paper determines collision frequency and collapse frequency of arch ring of the bridge by means of the three probability integral method.In addition,the paper determines the risk grade of ship collision the bridge according to the risk level of industry and risk assessment matrix and in combination with the calculated results of the three probability integral method.

  7. The Higgs Bridge

    CERN Document Server

    Allen, Roland E

    2013-01-01

    The particle recently discovered at the Large Hadron Collider near Geneva is almost certainly a Higgs boson, the long-sought completion of the Standard Model of particle physics. But this discovery, an achievement by more than six thousand scientists (including students), is actually much more than a mere capstone of the Standard Model. It instead represents a bridge from the Standard Model to exciting discoveries of the future, at higher energies or in other experiments, and to the properties of matter at very low temperatures. The mere existence of a particle with zero spin implies a need for new physics, with the most likely candidate being supersymmetry, which requires that every known particle has a superpartner yet to be discovered. And phenomena similar to the Higgs are seen in superconducting metals and superfluid gases at low temperatures, which extend down to a millionth or even a billionth of a degree Kelvin. So the discovery of a Higgs boson has a central place in our attempts both to achieve a tr...

  8. Isogeometric analysis: a powerful numerical tool for the elastic analysis of historical masonry arches

    Science.gov (United States)

    Cazzani, Antonio; Malagù, Marcello; Turco, Emilio

    2016-03-01

    We illustrate a numerical tool for analyzing plane arches such as those frequently used in historical masonry heritage. It is based on a refined elastic mechanical model derived from the isogeometric approach. In particular, geometry and displacements are modeled by means of non-uniform rational B-splines. After a brief introduction, outlining the basic assumptions of this approach and the corresponding modeling choices, several numerical applications to arches, which are typical of masonry structures, show the performance of this novel technique. These are discussed in detail to emphasize the advantage and potential developments of isogeometric analysis in the field of structural analysis of historical masonry buildings with complex geometries.

  9. Properties of some statistics for AR-ARCH model with application to technical analysis

    Science.gov (United States)

    Huang, Xudong; Liu, Wei

    2009-03-01

    In this paper, we investigate some popular technical analysis indexes for AR-ARCH model as real stock market. Under the given conditions, we show that the corresponding statistics are asymptotically stationary and the law of large numbers hold for frequencies of the stock prices falling out normal scope of these technical analysis indexes under AR-ARCH, and give the rate of convergence in the case of nonstationary initial values, which give a mathematical rationale for these methods of technical analysis in supervising the security trends.

  10. Neonate with VACTERL Association and a Branchial Arch Anomaly without Hydrocephalus.

    Science.gov (United States)

    Velazquez, Danitza; Pereira, Elaine; Havranek, Thomas

    2016-03-01

    VACTERL (vertebral anomalies, anal atresia, cardiac defect, tracheoesophageal fistula, renal anomaly, limb anomalies) is an association of anomalies with a wide spectrum of phenotypic expression. While the majority of cases are sporadic, there is evidence of an inherited component in a small number of patients as well as the potential influence of nongenetic risk factors (maternal diabetes mellitus). Presence of hydrocephalus has been reported in VACTERL patients (VACTERL-H) in the past, with some displaying branchial arch anomalies. We report the unique case of an infant of diabetic mother with VACTERL association and a branchial arch anomaly-in the absence of hydrocephalus.

  11. Carpal arch and median nerve changes during radioulnar wrist compression in carpal tunnel syndrome patients.

    Science.gov (United States)

    Marquardt, Tamara L; Evans, Peter J; Seitz, William H; Li, Zong-Ming

    2016-07-01

    The purpose of this study was to investigate the morphological changes of the carpal arch and median nerve during the application of radiounlarly directed compressive force across the wrist in patients with carpal tunnel syndrome. Radioulnar compressive forces of 10 N and 20 N were applied at the distal level of the carpal tunnel in 10 female patients diagnosed with carpal tunnel syndrome. Immediately prior to force application and after 3 min of application, ultrasound images of the distal carpal tunnel were obtained. It was found that applying force across the wrist decreased the carpal arch width (p 1234-1240, 2016. PMID:26662276

  12. Mycotic aneurysm of the aortic arch presenting with left vocal cord palsy.

    Science.gov (United States)

    Tokmaji, George; Gosev, Igor; Kumamaru, Kanako Kunishima; Bolman, Ralph Morton

    2013-07-01

    We report a case of a 71-year-old man with a mycotic aneurysm of the aortic arch who presented with progressive hoarseness. Three weeks prior to this event the patient was admitted to an outside hospital in septic condition and was diagnosed with a mycotic abdominal aortic aneurysm. Resection of the infected abdominal aortic aneurysm with right axillofemoral and femoral-femoral bypass grafts was performed and the patient was discharged home on intravenous antibiotics. At our institution, the aortic arch aneurysm was treated with extensive debridement and replaced with a Dacron prosthesis under circulatory arrest with antegrade cerebral perfusion through the axillofemoral bypass. PMID:23816081

  13. Endovascular Treatment for Proximal Anastomotic Pseudoaneurysm after Total Arch Replacement in Behcet's Disease.

    Science.gov (United States)

    Sakata, Tomoki; Ueda, Hideki; Watanabe, Michiko; Kohno, Hiroki; Tamura, Yusaku; Abe, Shinichiro; Inage, Yuichi; Ikeuchi, Hiroki; Kanda, Tomoyoshi; Fujii, Masahiko; Matsumiya, Goro

    2016-07-01

    A 17-year-old patient underwent total arch replacement for aortic arch aneurysm due to vascular Behcet's disease (BD). Follow-up computed tomography, performed 6 months after the operation, demonstrated pseudoaneurysm formation at the proximal anastomotic site. We performed endovascular treatment and used a short stent graft that was originally designed for abdominal aortic aneurysm. To avoid the occlusion of the coronary or brachiocephalic artery (BCA) due to stent graft migration, we used right ventricular rapid pacing and BCA ballooning. Thus, we believe that endovascular treatment can be used for anastomotic complications in the ascending aorta after open surgery for connective tissue disorders including BD. PMID:27174345

  14. Median deficiency in the posterior arch of the atlas vertebra: a case report

    Directory of Open Access Journals (Sweden)

    Kaushal P

    2011-04-01

    Full Text Available Isolated cases of partial agenesis of atlas were initially considered benign variations, without any clinical or pathological significance. However, there is increasing evidence that neurological symptoms may occur even after minor cervical trauma in subjects with defects in the posterior arch of the atlas. The present case study describes a rare case of median deficiency in the posterior arch of atlas vertebra. The knowledge of this benign variation is crucial as it may aid clinicians in correct management of subjects presenting with resolution of symptoms and avoid excessive investigations.

  15. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    Directory of Open Access Journals (Sweden)

    H. Mirzabozorg

    2014-01-01

    Full Text Available The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams.

  16. Classification of the height and flexibility of the medial longitudinal arch of the foot

    Directory of Open Access Journals (Sweden)

    Nilsson Mette

    2012-02-01

    Full Text Available Abstract Background The risk of developing injuries during standing work may vary between persons with different foot types. High arched and low arched feet, as well as rigid and flexible feet, are considered to have different injury profiles, while those with normal arches may sustain fewer injuries. However, the cut-off values for maximum values (subtalar position during weight-bearing and range of motion (ROM values (difference between subtalar neutral and subtalar resting position in a weight-bearing condition for the medial longitudinal arch (MLA are largely unknown. The purpose of this study was to identify cut-off values for maximum values and ROM of the MLA of the foot during static tests and to identify factors influencing foot posture. Methods The participants consisted of 254 volunteers from Central and Northern Denmark (198 m/56 f; age 39.0 ± 11.7 years; BMI 27.3 ± 4.7 kg/m2. Navicular height (NH, longitudinal arch angle (LAA and Feiss line (FL were measured for either the left or the right foot in a subtalar neutral position and subtalar resting position. Maximum values and ROM were calculated for each test. The 95% and 68% prediction intervals were used as cut-off limits. Multiple regression analysis was used to detect influencing factors on foot posture. Results The 68% cut-off values for maximum MLA values and MLA ROM for NH were 3.6 to 5.5 cm and 0.6 to 1.8 cm, respectively, without taking into account the influence of other variables. Normal maximum LAA values were between 131 and 152° and normal LAA ROM was between -1 and 13°. Normal maximum FL values were between -2.6 and -1.2 cm and normal FL ROM was between -0.1 and 0.9 cm. Results from the multivariate linear regression revealed an association between foot size with FL, LAA, and navicular drop. Conclusions The cut-off values presented in this study can be used to categorize people performing standing work into groups of different foot arch types. The results of this

  17. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

    We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200 nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (> 100 nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (< 60 nm), earlier reported to be mineral bridges, found to be such.

  18. Simulation of multivariate diffusion bridges

    DEFF Research Database (Denmark)

    Bladt, Mogens; Finch, Samuel; Sørensen, Michael

    We propose simple methods for multivariate diffusion bridge simulation, which plays a fundamental role in simulation-based likelihood and Bayesian inference for stochastic differential equations. By a novel application of classical coupling methods, the new approach generalizes a previously...

  19. Applications of overburden conveyor bridges

    Energy Technology Data Exchange (ETDEWEB)

    Schachtschneider, H.

    1987-06-01

    In large scale surface mines of the capacities required today, a cross-pit operation with overburden conveyor bridges is the most economical method of overburden removal and disposal. In order to provide the production capacity required in surface mining equipment by the GDR brown coal industry, VEB Schwermaschinenbau Lauchhammerwerk undertook the design and manufacture of standard overburden conveyor bridges for cut heights of 34 m, 45 m and 60 m. All three base types may be equipped to match the site specific geological and geotechnical conditions, and to meet customer's demands. Specifications of the bridges are given as well as details of conveyor belt speeds, modifications to the standards, and number manufactured. Design problems faced with the 60 m bridge are discussed, together with details of the superstructure, method of operation, transportation rates, structural steel used, assembly and power supply. 5 refs.

  20. Bridge Culture of Langde Village

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Langde, a village in Leishan County ofsouthwestern Guizhou province, is known for itslarge number of unique bridges bearing the distinctdesign style of the Miao ethnic group. Animpressive variety of well-preserved ancient

  1. ANGIOGRAPHIC ASPECTS OF MYOCARDIAL BRIDGES

    Directory of Open Access Journals (Sweden)

    Sujatha. M

    2015-12-01

    Full Text Available Introduction: The segment of epicardial coronary artery that traverses intramurally through the myocardium and bridged by a bunch of cardiac muscle fibers is called tunneled artery or intramural artery. The band of cardiac muscle fibers passing over the tunneled artery segment is named as myocardial bridge. During angiography milking effect is observed during systole due to the external pressure of muscle fibers on the tunneled artery that leads to narrowing of vessel lumen and further ischemia. Materials & Methods: It is a prospective study performed from 2012- 2015 in cardiac centers available around Tirupati, Andhra Pradesh, South India. A total number of 2015 adult patients who underwent diagnostic coronary angiography were evaluated to detect myocardial bridges. With the informed consent the relevant data was collected from the patients and analyzed. Results: The prevalence of myocardial bridges was 3.17%. Among the 2015 patients 70.7% are males and 29.2% are females. Among 64 myocardial bridge positive cases 62.5% were male and 37.5% were female patients. Regarding coronary dominance 84% were right dominant and 14.4% were left dominant and 1.6% are balanced. The percentage incidence of myocardial bridging according to dominance was 3.01% for right dominant patients, 4.12% for left dominant patients and 3.1% for balanced dominant patients. In all the myocardial bridge positive cases they were located on the left anterior descending artery (LAD. According to diagnosis the patients with normal coronaries were 22.6%, patients with MILD CAD were 17.9%, patients with single vessel disease were 23.4%, patients with two vessel disease were 14.7% and the patients with triple vessel disease were 21.3%. The 64 myocardial bridging cases were grouped in to three groups according to their age. Incidence of double bridges was observed in 3 cases of which 66.7% males & 33.3% in females. Conclusion: These results show that Andhra Pradesh population are

  2. The stories of two bridges in Ghana

    DEFF Research Database (Denmark)

    Andreasen, Jørgen

    2004-01-01

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

  3. An Expert System for Concrete Bridge Management

    DEFF Research Database (Denmark)

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

    1997-01-01

    The importance of bridge repair versus new bridge construction has risen in recent decades due to high deterioration rates that have been observed in these structures. Budgets both for building new bridges and keeping the existing ones are always limited. To help rational decision-making, bridge...

  4. Stability of liquid crystalline bridges

    Science.gov (United States)

    Mahajan, Milind P.; Tsige, Mesfin; Taylor, P. L.; Rosenblatt, Charles

    1999-02-01

    The stability of cylindrical bridges of the liquid crystal octylcyanobiphenyl in an immiscible liquid bath was investigated in the nematic and smectic A phases. In the nematic phase the bridge was found to destabilize at a length-to-diameter (slenderness) ratio R similar to that of ordinary Newtonian fluids. On the other hand, the Bingham behavior of the smectic A phase, i.e., an apparent yield stress, enabled the formation of stable columns with R well in excess of π.

  5. Dental arch dimensions in the mixed dentition: a study of Brazilian children from 9 to 12 years of age

    Directory of Open Access Journals (Sweden)

    Fabiane Louly

    2011-04-01

    Full Text Available OBJECTIVE: This study evaluated dental arch dimensional changes of Brazilian children. MATERIAL AND METHODS: Dental casts were taken from 66 children (29 males; 37 females with normal occlusion selected among 1,687 students from public and private schools aged 9, 10, 11 and 12 years, according to the following criteria: Class I canine and molar relationships; well-aligned upper and lower dental arches; mixed dentition; good facial symmetry; no previous orthodontic treatment. Dental arch dimensions were taken by one examiner using the Korkhaus' compass and a digital pachymeter. ANOVA test was applied to compare the arch dimensions at the different ages and the t-test was used to compare the arch dimensions of male and female subjects. Arch forms were compared by means of chi-square tests. RESULTS: Only the maxillary anterior segment length showed a statistically signifcant increase from 10 to 12 years of age. Males had a signifcantly larger maxillary depth than females at the age range evaluated. The predominant dental arch form found was elliptical. CONCLUSIONS: In the studied age range, anterior maxillary length increased from 10 to 12 years of age, males had larger maxillary depth than females and the predominant arch form was elliptical.

  6. Tracheal compression due to an elongated aortic arch in patients with congenital heart disease: evaluation using multidetector-row CT

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Noriko; Hayabuchi, Yasunobu; Inoue, Miki; Sakata, Miho; Nabo, Manal Mohamed Helmy; Nakagawa, Ryuji; Saijo, Takahiko; Kagami, Shoji [University of Tokushima, Department of Pediatrics, Tokushima (Japan)

    2009-10-15

    The airway can become obstructed as a result of compression by an elongated aortic arch. In this study we evaluated tracheal compression using multidetector-row CT in patients with congenital heart disease and an elongated aortic arch. The trachea was measured at the level of the aortic arch in 205 children and young adults and then the severity of tracheal compression was determined by measuring the tracheal diameter ratio (short axis diameter/long axis diameter). Patients were divided as follows: group I (normal aortic arch; n=166), group II (transversely running aortic arch; n=22), and group III (elongated aortic arch; n=17). From the viewpoint of the relationship of the great arteries, group II had D-malposition, and group III had L-malposition. Age, height, weight and body surface area were significantly correlated with the short and long axis diameter in group I. There was a negative correlation between tracheal diameter ratio and the physical size parameters. The tracheal diameter ratio in group III was 0.50{+-}0.13, which was significantly lower than in groups I and II (P<0.01 and 0.05, respectively). Even apparently asymptomatic patients with an elongated aortic arch can have tracheal compression. An elongated aortic arch may be a useful predictor of tracheal compression. (orig.)

  7. Maxillary Arch Dimensions and Spectral Characteristics of Children with Cleft Lip and Palate Who Produce Middorsum Palatal Stops

    Science.gov (United States)

    Zajac, David J.; Cevidanes, Lucia; Shah, Sonam; Haley, Katarina L.

    2012-01-01

    Purpose: The purpose of this study was twofold: (a) to determine maxillary arch dimensions of children with repaired cleft lip and palate (CLP) who produced middorsum palatal stops and (b) to describe some spectral characteristics of middorsum palatal stops. Method: Maxillary arch width, length, and height dimensions and first spectral moments of…

  8. Treatment of flaring of the costal arch after the minimally invasive pectus excavatum repair (Nuss procedure) in children.

    NARCIS (Netherlands)

    Bosgraaf, R.P.; Aronson, D.C.

    2010-01-01

    Flaring of the costal arch may be part of the pectus excavatum deformity. This aspect will in rare cases be even worsen after the Nuss repair. This remaining deformity can be treated with a minimal subperichondral partial resection of the costal arch cartilage. In 5 patients, this additional techniq

  9. Treatment of flaring of the costal arch after the minimally invasive pectus excavatum repair (Nuss procedure) in children

    NARCIS (Netherlands)

    R.P. Bosgraaf; D.C. Aronson

    2010-01-01

    Flaring of the costal arch may be part of the pectus excavatum deformity. This aspect will in rare cases be even worsen after the Nuss repair. This remaining deformity can be treated with a minimal subperichondral partial resection of the costal arch cartilage. In 5 patients, this additional techniq

  10. Signs and symptoms related to temporomandibular disorders--Follow-up of subjects with shortened and complete dental arches.

    NARCIS (Netherlands)

    Witter, D.J.; Kreulen, C.M.; Mulder, J.; Creugers, N.H.J.

    2007-01-01

    OBJECTIVE: To assess prevalence of cardinal signs and symptoms related to temporomandibular disorders (TMD) in subjects with shortened dental arches and to clarify the individual course of these signs and symptoms. METHODS: In this 9-year follow-up study, subjects with shortened dental arches (n=74)

  11. Aortic Arch Vessel Anomalies Associated with Persistent Trigeminal Artery: (Report of a Case

    Directory of Open Access Journals (Sweden)

    M. Lotfi

    2008-01-01

    Full Text Available Introduction: Developmental anomalies of the aortic arch vessels are well described entities. Persistent trigeminal artery (PTA is the most common type of the four anomalous carotid-basilar anastomoses, and is due to abnormal persistence of what are normal transient communications between the embryonic forebrain and hindbrain arterial systems. Herein we report a previously undescribed variant consisting of coexistence of the PTA, truncus bicaroticus, and di-rect origin of left vertebral artery from aortic arch. "nCase Presentation: A 46 year-old man was admitted in the Namazi hospital with severe nausea, vomiting, severe headache, and decreased level of conscious-ness. Computed tomography scan revealed intraven-tricular hemorrhage with no evidence of subarach-noid hemorrhage. The patient was referred for four-vessel cerebral arteriography to evaluate the entire cerebral vascular anatomy. Arch aortography demon-strated the right subclavian artery as the first branch of the arch. The left vertebral artery arose directly from the arch as the second branch. The third branch consisted of a common trunk giving rise to the right and left common carotid arteries (Truncus Bicaroti-cus. The left subclavian artery arose as the final branch of the aortic arch. Selective angiography con-firmed that left vertebral artery did not arise from the left subclavian artery. Left vertebral artery angiogra-phy revealed a persistent trigeminal artery, with fill-ing of left internal carotid artery and its branches. No aneurysm or any other vascular abnormality was de-tected in this patient. The patient was subsequently managed by evacuation of IVH and ventriculostomy."nDiscussion: The usual configuration of three branches from the aortic arch is found in 60-80% of popula-tion. The left vertebral artery normally originate along the superior portion of the left subclavian ar-tery. However, this artery is subject to a number of variations; among all; the most common

  12. An Experimental Investigation of the Dynamic Behavior of an In-Plane MEMS Shallow Arch Under Electrostatic Excitation

    KAUST Repository

    Ramini, Abdallah

    2016-01-20

    We present experimental investigation of the nonlinear dynamics of a clamped-clamped in-plane MEMS shallow arch when excited by an electrostatic force. We explore the dynamic behaviors of the in-plane motion of the shallow arches via frequency sweeps in the neighborhood of the first resonance frequency. The shallow arch response is video microscopy recorded and analyzed by means of digital imaging. The experimental data show local softening behavior for small DC and AC loads. For high voltages, the experimental investigation reveals interesting dynamics, where the arch exhibits a dynamic snap-Through behavior. These attractive experimental results verify the previously reported complex behavior of in-plane MEMS arches and show promising results to implement these structures for variety of sensing and actuation applications. © Copyright 2015 by ASME.

  13. A quadrant tray and bite registration as an alternative to dual-arch impressions for fixed prosthetics: a clinical and dental laboratory technique.

    Science.gov (United States)

    Hammond, Barry D; Myers, Michael L; Haywood, Van B

    2011-01-01

    To perform fixed prosthodontic procedures, dentists take a full-arch or quadrant impression and articulate the casts. The dual-arch impression technique is a popular quadrant technique for crown fabrication. The technique described in this article, which uses a quadrant impression and separate interocclusal record, offers several advantages over the traditional dual-arch method.

  14. C1 anterior arch preservation in transnasal odontoidectomy using three-dimensional endoscope: A case report

    Directory of Open Access Journals (Sweden)

    Francesco Zenga

    2015-01-01

    Conclusions: The stereoscopic perception augmented the precision of the surgical gesture in the deep field. The importance of a 3D view relates to the depth of field, which a two-dimensional endoscopy cannot provide. This affects the preservation of the C1 anterior arch because of the presence of critical structures that are exposed to potential damage if not displayed.

  15. Optimization design of foundation excavation for Xiluodu super-high arch dam in China

    Directory of Open Access Journals (Sweden)

    Qixiang Fan

    2015-04-01

    Full Text Available With better understanding of the quality and physico-mechanical properties of rocks of dam foundation, and the physico-mechanical properties and structure design of arch dam in association with the foundation excavation of Xiluodu arch dam, the excavation optimization design was proposed for the foundation surface on the basis of feasibility study. Common analysis and numerical analysis results demonstrated the feasibility of using the weakly weathered rocks III1 and III2 as the foundation surface of super-high arch dam. In view of changes in the geological conditions at the dam foundation along the riverbed direction, the design of extending foundation surface excavation area and using consolidating grouting and optimizing structure of dam bottom was introduced, allowing for harmonization of the arch dam and foundation. Three-dimensional (3D geomechanics model test and finite element analysis results indicated that the dam body and foundation have good overload stability and high bearing capacity. The monitoring data showed that the behaviors of dam and foundation correspond with the designed patterns in the construction period and the initial operation period.

  16. A quantitative approach for measuring crowding in the dental arch: Fourier descriptors.

    Science.gov (United States)

    Lestrel, Pete E; Takahashi, Osamu; Kanazawa, Eisaku

    2004-06-01

    Dental crowding is defined as a discrepancy between tooth size and jaw size that results in a misalignment of the tooth row. Proposed reasons for crowding include excessively large teeth, small jaws, and a combination of both. Nevertheless, the parameters that would allow the prediction of crowding have not been identified. This study compared the shape of crowded and uncrowded dental arches, matched for size and sex. The application of elliptical Fourier functions (EFFs) provided an accurate numeric description of the dental arch form. Dental casts from the Nihon University School of Dentistry at Matsudo, Chiba, Japan, were studied. Group I, the control group, consisted of 118 dental cast pairs (49 female, 69 male, aged 20.40 +/- 1.68 years [mean +/- SD]) with little or no crowding. Group II, which exhibited crowding, consisted of 78 dental cast pairs (64 female, 14 male, aged 19.67 +/- 4.95 years). From photographs, a set of 24 homologous points describing the tooth row was identified. These points were then fitted with EFFs. Each maxillary and mandibular outline was subsequently standardized for size by scaling the bounded area to a constant 10,000 mm(2). These "shape only" data were used to assess differences between arches in the 2 groups. By multivariate analysis of variance, statistically significant shape differences between groups I and II were obtained for both arches. Patients with crowding exhibited more variability than did the controls. This variability was illustrated with canonical axes derived from discriminant function analysis. PMID:15179396

  17. A longitudinal study of dental arch morphology in children with the syndrome of Crouzon or Apert

    NARCIS (Netherlands)

    J.H. Reitsma; P. Elmi; E.M. Ongkosuwito; P.H. Buschang; B. Prahl-Andersen

    2013-01-01

    The aim of this study was to compare changes in dental arch morphology between patients with Crouzon syndrome or Apert syndrome and controls. Children between 4 and 14 yr of age with Crouzon syndrome (n = 40) or Apert syndrome (n = 28) were compared with non-syndromic controls (n = 457) in terms of

  18. Double aortic arch as a source of airway obstruction in a child

    Directory of Open Access Journals (Sweden)

    Sambhunath Das

    2015-01-01

    Full Text Available Double aortic arch (DAA is a congenital vascular anomaly. The diagnosis was difficult till the child was symptomatic, and other causes were ruled out. We present the interesting images of a child of respiratory distress because of tracheal compression from DAA.

  19. Right-sided aortic arch with anomalous origin of the left subclavian artery: Case report

    Directory of Open Access Journals (Sweden)

    Vučurević Goran

    2011-01-01

    Full Text Available Introduction. A right-sided aortic arch is a rare congenital defect of the aorta with incidence of 0.05% to 0.1% reported in published series. Usually it is associated with congenital heart anomalies and esophageal and tracheal compression symptoms. We present a case of a right-sided aortic arch of anomalous left subclavian artery origin, accidentally revealed during multislice CT (MSCT supraaortic branches angiography. Case Outline. A 53-year-old female patient was examined at the Outpatients’ Unit of the Vascular Surgery University Clinic for vertigo, occasional dizziness and difficulty with swallowing. Physical examination revealed a murmur of the left supraclavicular space, with 15 mmHg lower rate of arterial tension on the left arm. Ultrasound of carotid arteries revealed 60% stenosis of the left subclavian artery and bilateral internal carotid artery elongation. MSCT angiography revealed a right-sided aortic arch with aberrant separation of the left subclavian artery that was narrowed 50%, while internal carotid arteries were marginally elongated. There was no need for surgical treatment or percutaneous interventions, so that conservative treatment was indicated. Conclusion. A right-sided aortic arch is a very rare anomaly of the location and branching of the aorta. Multislice CT angiography is of great importance in the diagnostics of this rare disease.

  20. Carbon Dioxide in the Aortic Arch: Coronary Effects and Implications in a Swine Study

    International Nuclear Information System (INIS)

    Purpose: CO2 angiography is considered dangerous in the aortic arch where bubbles may cause critical cerebral and cardiac ischemia. We investigated CO2distribution, physiologic effects in the heart, methods of detection and treatments. Methods: Eight pigs had CO2and iodinated contrast arch angiograms in supine and both lateral decubitus positions. An electrocardiogram, physiologic data and cardiac ultrasound were obtained. Therapies included precordial thumps and rolls to lateral decubitus positions. Results: Supine high descending aorta CO2 injections floated retrograde up the arch during diastole and preferentially filled the right coronary artery (RCA): mean score 3.5 (of 4), in nominate artery 2.4, left coronary artery 1.2; n = 17; p = 0.0001. Aortic root injections preferentially filled the RCA when the animal was supine, left coronary in the right decubitus position, and showed a diffuse pattern in the left decubitus position. Right decubitus rolls filled both coronaries causing several lethal arrhythmias. Precordialthumps successfully cleared CO2. Ultrasound is a sensitive detector of myocardial CO2. Conclusion: Arch distribution of CO2 primarily involves the RCA. Diagnostic ultrasound detects cardiac CO2 well. Precordial thumps are an effective treatment

  1. Evaluation of the Occlusion and Arch Dimensions in the Primary Dentition of an Iranian Population

    Directory of Open Access Journals (Sweden)

    Maryam Talebi

    2013-12-01

    Full Text Available Introduction: The objective of this study was to gather information about normal occlusion and arch dimensions in the primary teeth of the children belonging to an Iranian population. Methods: This descriptive cross-sectional study was performed on 68 children from the city of Mashhad in the 3-5 age range. Dental arch dimensions, interrelationships of primary canine and second molars, overbite and overjet were evaluated. Results: Primate space was observed on both sides of the arch in 82.2% of the subjects. The most prevalent type of primary molar relationship was flush terminal plane (52.1% followed by distal step (31.3% and then mesial step (16.7%. The primary canine relationship was ranked in the descending order of prevalence as Class I (77.1%, Class II (13.5%, end-to-end (5.2% and Class III (4.2%. Normal overbite and normal overjet was observed in 50% and 81.3% of cases, respectively. Conclusion: This study provides an insight into the dental arch dimensions, occlusion, spacing and crowding in primary dentition in Iranian children. In most of the cases, primate space and flush terminal plane were observed.

  2. Evaluation of the Occlusion and Arch Dimensions in the Primary Dentition of an Iranian Population

    Directory of Open Access Journals (Sweden)

    Maryam Talebi

    2013-01-01

    Full Text Available Introduction: The objective of this study was to gather information about normal occlusion and arch dimensions in the primary teeth of the children belonging to an Iranian population. Methods: This descriptive cross-sectional study was performed on 68 children from the city of Mashhad in the 3-5 age range. Dental arch dimensions, interrelationships of primary canine and second molars, overbite and overjet were evaluated. Results: Primate space was observed on both sides of the arch in 82.2% of the subjects. The most prevalent type of primary molar relationship was flush terminal plane (52.1% followed by distal step (31.3% and then mesial step (16.7%. The primary canine relationship was ranked in the descending order of prevalence as Class I (77.1%, Class II (13.5%, end-to-end (5.2% and Class III (4.2%. Normal overbite and normal overjet was observed in 50% and 81.3% of cases, respectively. Conclusion: This study provides an insight into the dental arch dimensions, occlusion, spacing and crowding in primary dentition in Iranian children. In most of the cases, primate space and flush terminal plane were observed.

  3. Effect of dental arch convexity and type of archwire on frictional forces

    NARCIS (Netherlands)

    Fourie, Zacharias; Ozcan, Mutlu; Sandham, John

    2009-01-01

    Introduction: Friction measurements in orthodontics are often derived from models by using brackets placed on flat models with various straight wires. Dental arches are convex in some areas. The objectives of this study were to compare the frictional forces generated in conventional flat and convex

  4. Estimation and asymptotic inference in the first order AR-ARCH model

    DEFF Research Database (Denmark)

    Lange, Theis; Rahbek, Anders; Jensen, Søren Tolver

    2011-01-01

    This article studies asymptotic properties of the quasi-maximum likelihood estimator (QMLE) for the parameters in the autoregressive (AR) model with autoregressive conditional heteroskedastic (ARCH) errors. A modified QMLE (MQMLE) is also studied. This estimator is based on truncation of individual...

  5. Three-Dimensional Aquila Rift: Magnetized HI Arch Anchored by Molecular Complex

    CERN Document Server

    Sofue, Yoshiaki

    2016-01-01

    Three dimensional structure of the Aquila Rift of magnetized neutral gas is investigated by analyzing HI and CO line data. The projected distance on the Galactic plane of the HI arch of the Rift is ~250 pc from the Sun. The HI arch emerges at l~ 30 deg, reaches to altitudes as high as ~ 500 pc above the plane at l~ 350deg, and returns to the disk at l~270 deg. The extent of arch at positive latitudes is ~1 kpc and radius is ~100 pc. The eastern root is associated with the giant molecular cloud complex, which is the main body of the optically defined Aquila Rift. The HI and molecular masses of the Rift are estimated to be M_HI~1.4x10^5Msun and M_H2 ~3x10^5 Msun. Gravitational energies to lift the gases to their heights are E_grav: HI ~1.4x10^51 and E_grav: H_2 ~0.3x10^51 erg, respectively. Magnetic field is aligned along the HI arch of the Rift, and the strength is measured to be B~10 microG using Faraday rotation measures of extragalactic radio sources. The magnetic energy is estimated to be E_mag~1.2x10^51 e...

  6. Prenatal diagnosis of the rare association of common arterial trunk and double aortic arch

    OpenAIRE

    Rock, Andrea; Eltayeb, Osama; Camarda, Joseph; Gotteiner, Nina

    2016-01-01

    Key Clinical Message Common arterial trunk with associated double aortic arch is a very rare constellation of congenital heart disease. Prenatal diagnosis allows for surgical repair prior to development of respiratory morbidity, which is otherwise described in all cases with this association.

  7. The impact of foot arch height on quality of life in 6-12 year olds

    Directory of Open Access Journals (Sweden)

    Daniel López López

    2015-01-01

    Full Text Available Objective:To determine whether arch height has an effect on the health-related quality of life of schoolchildren.Methods:One hundred and thirteen schoolchildren attended an out-patient centre where self-reported data were recorded, their feet were classified into one of three groups according to their arch index (high, normal or low and the scores obtained from the Foot Health Status Questionnaire (FHSQ - Spanish version were compared.Results:The groups with high, low and normal arch recorded lower scores in Section One for the general foot health and footwear domains and higher scores in foot pain and foot function. In Section Two they obtained lower scores in general health and higher scores in physical activity, social capacity and vigour.Conclusions:Comparison of the scores obtained reveals that arch height has a negative impact on quality of life. Given the limited extent of available evidence in respect of the aetiology and treatment of foot diseases and deformities, these findings reveal the need to implement programmes to promote foot health and carry out further research into this commonly occurring disabling condition.

  8. ENTRAINMENT OF THE BREATHING RHYTHM OF THE CARP BY IMPOSED OSCILLATION OF THE GILL ARCHES

    NARCIS (Netherlands)

    DEGRAAF, PJF; ROBERTS, BL

    1991-01-01

    Artificial oscillation imposed onto the gill arches could modify the respiratory rhythm in the carp Cyprinus carpio. The degree of modification depended upon the frequency and amplitude of the applied movement. Oscillation at frequencies close to the spontaneous respiratory rhythm and at amplitudes

  9. Ross Errilly Franciscan Friary, north chancel wall, tomb niche, jamb, arch and hood moulding

    OpenAIRE

    O'Donovan, Danielle

    2002-01-01

    Moulding of tomb niche, jamb and arch moulding from intrados comprises: hollow chamfer, right-angled rebate, hollow chamfer, quadrant. Hood comprises frontal fillet, hollow chamfer. In design, the tomb niche looks like those from Quin and Ennis, which are related to the Limerick/Kerry examples. The moulding looks very like that of the west door.

  10. The Diversity of High- and Intermediate-Velocity Clouds Complex C versus IV Arch

    CERN Document Server

    Richter, P; Wakker, B P; Savage, B D; Tripp, T M; Murphy, E M; Kalberla, P M W; Jenkins, E B

    2001-01-01

    We present Far Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS) observations of interstellar ultraviolet absorption lines in the Galactic high-velocity cloud Complex C and the Intermediate Velocity Arch (IV Arch) in direction of the quasar PG 1259+593 (l=120,b=+58 deg). Absorption lines from CII, NI, NII, OI, AlII, SiII, PII, SII, ArI, FeII, and FeIII are used to study the atomic abundances in these two halo clouds at V_LSR=-130 km/s (Complex C) and V_LSR=-55 km/s (IV Arch). The OI/HI ratio provides the best measure of the overall metallicity in the diffuse interstellar medium, because ionization effects do not alter the ratio, and oxygen is at most only lightly depleted from the gas into dust grains. For Complex C, we find an oxygen abundance of 0.093 (+0.125, -0.047) solar, consistent with the idea that Complex C represents the infall of low metallicity gas onto the Milky Way. In contrast, the oxygen abundance in the IV Arch is 0.98 (+1.21,-0.46) solar, which indicat...

  11. [Antegrade unilateral perfusion of the brain through the brachiocephalic trunk in operations on the aortic arch].

    Science.gov (United States)

    Kozlov, B N; Panfilov, D S; Kuznetsov, M S; Ponomarenko, I V; Nasrashvili, G G; Shipulin, V M

    2016-01-01

    Presented herein is a technique of unilateral antegrade perfusion of the brain in operations on the aortic arch. The method makes it possible to perform both systemic artificial circulation and adequate physiological perfusion of the brain, promoting minimization of the number of neurological complications. PMID:27100557

  12. Multimodal optical measurement in vitro of surface deformations and wall thickness of the pressurized aortic arch.

    Science.gov (United States)

    Genovese, Katia; Humphrey, Jay D

    2015-04-01

    Computational modeling of arterial mechanics continues to progress, even to the point of allowing the study of complex regions such as the aortic arch. Nevertheless, most prior studies assign homogeneous and isotropic material properties and constant wall thickness even when implementing patient-specific luminal geometries obtained from medical imaging. These assumptions are not due to computational limitations, but rather to the lack of spatially dense sets of experimental data that describe regional variations in mechanical properties and wall thickness in such complex arterial regions. In this work, we addressed technical challenges associated with in vitro measurement of overall geometry, full-field surface deformations, and regional wall thickness of the porcine aortic arch in its native anatomical configuration. Specifically, we combined two digital image correlation-based approaches, standard and panoramic, to track surface geometry and finite deformations during pressurization, with a 360-deg fringe projection system to contour the outer and inner geometry. The latter provided, for the first time, information on heterogeneous distributions of wall thickness of the arch and associated branches in the unloaded state. Results showed that mechanical responses vary significantly with orientation and location (e.g., less extensible in the circumferential direction and with increasing distance from the heart) and that the arch exhibits a nearly linear increase in pressure-induced strain up to 40%, consistent with other findings on proximal porcine aortas. Thickness measurements revealed strong regional differences, thus emphasizing the need to include nonuniform thicknesses in theoretical and computational studies of complex arterial geometries.

  13. Changes in lower dental arch dimensions and tooth alignment in young adults without orthodontic treatment

    Directory of Open Access Journals (Sweden)

    Bruno Aldo Mauad

    2015-06-01

    Full Text Available OBJECTIVE: The aim of this longitudinal study, comprising young adults without orthodontic treatment, was to assess spontaneous changes in lower dental arch alignment and dimensions. METHODS: Twenty pairs of dental casts of the lower arch, obtained at different time intervals, were compared. Dental casts obtained at T1 (mean age = 20.25 and T2 (mean age = 31.2 were compared by means of paired t-test (p 0.05. Furthermore, incisors irregularity at T2 could not be predicted due to the severity of this variable at T1 (p = 0.5051. CONCLUSION: Findings suggest that post-growth maturation of the lower dental arch leads to a reduction of dental arch dimensions as well as to a mild, yet significant, increase in dental crowding, even in individuals without orthodontic treatment. Furthermore, dental alignment in the third decade of life cannot be predicted based on the severity of dental crowding at the end of the second decade of life.

  14. Optimization design of foundation excavation for Xiluodu super-high arch dam in China

    Institute of Scientific and Technical Information of China (English)

    Qixiang Fan; Shaowu Zhou; Ning Yang

    2015-01-01

    With better understanding of the quality and physico-mechanical properties of rocks of dam foundation, and the physico-mechanical properties and structure design of arch dam in association with the foun-dation excavation of Xiluodu arch dam, the excavation optimization design was proposed for the foundation surface on the basis of feasibility study. Common analysis and numerical analysis results demonstrated the feasibility of using the weakly weathered rocks III1 and III2 as the foundation surface of super-high arch dam. In view of changes in the geological conditions at the dam foundation along the riverbed direction, the design of extending foundation surface excavation area and using consolidating grouting and optimizing structure of dam bottom was introduced, allowing for harmonization of the arch dam and foundation. Three-dimensional (3D) geomechanics model test and finite element analysis re-sults indicated that the dam body and foundation have good overload stability and high bearing capacity. The monitoring data showed that the behaviors of dam and foundation correspond with the designed patterns in the construction period and the initial operation period.

  15. Cephalic arch stenosis in autogenous brachiocephalic hemodialysis fistulas: results of cutting balloon angioplasty

    DEFF Research Database (Denmark)

    Heerwagen, Søren Thorup; Lönn, Lars; Schroeder, Torben V;

    2010-01-01

    Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose...

  16. Truncus arteriosus with aortic arch interruption: cardiovascular magnetic resonance findings in the unrepaired adult

    OpenAIRE

    Cook Stephen C; Thavendiranathan Paaladinesh; Arruda Janine; Verhaert David; Raman Subha V

    2010-01-01

    Abstract Truncus arteriosus (TA) is a rare congenital condition defined as a single arterial vessel arising from the heart that gives origin to the systemic, pulmonary and coronary circulations. We discuss the unique case of a 28 year-old female patient with unrepaired TA and interruption of the aortic arch who underwent cardiovascular magnetic resonance (CMR).

  17. Double aortic arch with double aneuploidy-rare anomaly in combined Down and Klinefelter syndrome

    NARCIS (Netherlands)

    M.F. Gerretsen; W. Peelen; L.A.J. Rammeloo; D.R. Koolbergen; J. Hruda

    2009-01-01

    A 14-month-old boy with double aneuploidy and a double aortic arch suffered from frequently recurrent severe feeding and respiratory problems. Chromosomal analysis showed a 48,XXY + 21 karyotype: a double aneuploidy of Down syndrome (DS) and Klinefelter syndrome (KS). Only four cases of double aneup

  18. Influence of underground water seepage flow on surrounding rock deformation of multi-arch tunnel

    Institute of Scientific and Technical Information of China (English)

    LI Xi-bing; ZHANG Wei; LI Di-yuan; WANG Qi-sheng

    2008-01-01

    Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in 3 dimensions(FLAC3D) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underground water seepage flow was taken into account or not. The distribution of displacement field around the multi-arch tunnel, which is influenced by the seepage field, was gained. The result indicates that the settlement values of the vault derived from coupling analysis are bigger when considering the seepage flow effect than that not considering. Through the contrast of arch subsidence quantities calculated by two kinds of computation situations, and the comparison between the calculated and measured value of tunnel vault settlement, it is found that the calculated value(5.7-6.0 mm) derived from considering the seepage effect is more close to the measured value(5.8-6.8 mm).Therefore, it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design.

  19. Earthquake analysis of arch and gravity dams including the effects of foundation inhomogeneity

    Institute of Scientific and Technical Information of China (English)

    LIN Gao; DU Jianguo; HU Zhiqiang

    2007-01-01

    Dam-foundation interaction plays an important role in the design of earthquake-resistant concrete arch and gravity dams.Geological conditions of the dam canyon are usually very complicated;however,in the literature,the damfoundation interaction analysis is often carried out based on the premise of a homogeneous unbounded foundation.In this paper,the effect of foundation inhomogeneity on the seismic response of arch and gravity dams was studied by means of scaled boundary finite element method (SBFEM).In order to satisfy the similarity requirement of SBFEM and simplify the computational effort,a subdomain approach and a conical representation of an unbounded foundation were proposed.The way of partitioning the domain and the selection of open angle and bottom radius of the cone model on the accuracy of the result were examined.Numerical examples show that the proposed approach is rational and efficient.Cases of foundation inhomogeneity with stiffness varying in accordance with an exponential function along the radial direction,and cases of foundation inhomogeneity with stiffness discontinuity and with weak interlayer strata on the earthquake response of concrete arch dams as well as gravity dams were analyzed.It was found that a homogeneous idealization of the unbounded foundation may sometimes greatly underestimate the maximum earthquake stress response of the dam.Therefore,taking into account the effect of foundation inhomogeneity for the earthquake safety assessment of concrete arch and gravity dams has great significance.

  20. The Application of 3D Laser Scanning in the Survey and Measuring of Guyue Bridge of Song Dynasty in Yiwu City

    Science.gov (United States)

    Lu, N.; Wang, Q.; Wang, S.; Zhang, R.

    2015-08-01

    It is believed that folding-arch is the transitional form from beam to curved arch. Guyue Bridge, built in JiaDing 6year (A.D 1213) of Southern Song Dynasty, located in Yiwu City, Zhejiang Province in China, is one of typical objective examples for this transition. It possesses high historical, scientific, artistic, cultural and social values. Facing severe environmental problems and deteriorated heritage situation, our conservation team selected 3D laser scanning as basic recording method, then acquired the precise threedimensional model. Measured the fundamental dimension and components' sizes, we analysed its stable state. Moreover, combined with historic documents, we reasonably speculated and calculated the original sizes and important scales at the building time. These findings have significant research values as well as evidential meanings for future conservation.